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APPLICATION

S OF GASCHROMATOGRAPHY

Edited by Reza

Davarnejadand MahboubehJafarhan!

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Applications of Gas Chromatography

Edited by Reza Davarnejad and Mahboubeh Jafarkhani

Published by InTech

Janeza Trdine 9, 51000 Rijeka, Croatia

Copyright 2012 InTech

A !ha"ter# are $"en A!!e## di#tributed under the Creative Co%%on# Attribution &'0

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en#ure# %a*i%u%di##e%inationand a(ider i%"a!t of our "ubi!ation#' After thi# (ork

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A""i!ation# of 2a# Chro%ato)ra"hy,

Edited by Reza Davarnejad and MahboubehJafarkhani

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Content#

Preface $II

Cha"ter 1 Gas Chromatography Application

in %upercritical &luid !'traction Process 1

Reza Davarnejad and Mo#tafa 8e#havarz Moraveji

Cha"ter / Interaction Parametersof %urfactant

i'tures by In"erse Gas Chromatography 1(

Eeuterio 9ui# Aran!ibia, abo C' !huz and u#ana M'3ardavid

Cha"ter & Applications of Chromatography )yphenated

Techni*ues in the &ield of +igninPyrolysis ,1

hubin :u, 2aojin 9v and Rui 9ou

Cha"ter ; #egradation Phenomena of

-eforming Catalyst in #I-.C&C /08i%ihiko u)iura

Cha"ter 5 -ecent %trategies in rganic -eactions

Catalyed by Phase Transfer Catalysts

and Analy2ed by Gas Chromatography 34

' A'

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refa!e

This book presents a critical review of various chromatography techniques for a

limited number of processes. Most techniques are illustrated by examples.

The processes described are necessarily limited to those which appear to the authors to

have the greatest validity and practical use. Wherever possible, we have includedrecommendations delineating the best techniques for analyzing each sample.

Recommended techniques are often illustrated by detailed examples.

Although the book is intended to serve primarily the practicing engineer, especially

the process or chemical engineer, other engineers (such as environmental engineers)

and chemists concerned with analyzing techniques may find it useful.

Most new techniques are still empirical in nature, although there are often theoretical

bases for the correlation; wherever possible, the theory is outlined to provide the user

with the foundation of the proposed chromatography techniques.

Special thanks are due to all respectful authors for their excellent contributions to this

book and to Ms. Martina Durovic and Ms. Daria Nahtigal for extensive assistance and

support.

Reza DavarnejadandMahboubeh Jafarkhani

Department of Chemical Engineering,

Faculty of Engineering,

Arak University

Iran

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1

Gas Chromatography Application inSupercritical Fluid Extraction Process

Reza Davarnejad* and Mostafa KeshavarzMoraveji Department of Chemical Engineering, Faculty of

Engineering, Arak University, Iran

1. Introduction

There are two types of application for gas chromatography (!" in thes#percritical $#id e%traction process& as chromatography is a type ofs#percritical e%traction apparat#ses which can separate a component from am#lti'component mi%t#re d#ring s#percritical e%traction& Therefore thisapplication can be the alternative to conventional gas chromatographywhich needs high temperat#res for the evaporation of the feed mi%t#re andfor li)#id chromatography where li)#id solvents may be replaced& This processres#lts in a dierent transport velocity along the stationary phase fordierent molec#les& Molec#les having wea+ interaction forces with thestationary phase are transported )#ic+ly while others with strong interactionsare transported slowly& ,eside the interactions with the stationary phase the

solvent power of the mobile phase determines the distrib#tion of thecomponents& -#rthermore s#percritical gases have a high solvent powerand e%ert this solvent power at low temperat#res&

.nother application of ! in s#percritical fl#id e%traction is consideration andanalysis of e%traction prod#ct& The obtained prod#cts from vario#s types ofs#percritical apparat#ses (s#ch as phase e)#ilibri#m and rate test apparat#s"sho#ld be analyzed& /owever dierent types of analyzer can be #sed b#t theconventional ! with a s#itable col#mn has widely been recommended&.ltho#gh several col#mns for detecting a lot of components have been designedand fabricated by some companies b#t d#e to lac+ing of s#itable col#mns forsome components or #nclear pea+s obtained from some col#mns an e%tra

process (s#ch as esteri0cation of the fractionated fish oil" before ! analyzeis sometimes re)#ired& 1n this application the samples obtained from thes#percritical e%traction apparat#s are not #nder press#re or their press#res havebro+en down by a damper (in online !"&

1n this chapter both types of ! application in s#percritical $#id e%traction withe%amples will be ill#strated&

2. Gas chromatography apparatus

1n s#percritical $#id chromatography (2-!" the mobile phase is a s#percriticalgas or a near critical li)#id& !ompared to gas chromatography (!" where

a gas is #nder ambient

* !orresponding.#thor

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2 Applications of Gas Chromatography

press#re (for e%ample in the second type of apparat#s applied in s#percriticalprocess" and li)#id chromatography (3!" where a li)#id is #sed as mobilephase the solvent power of the li)#id mobile phase in 2-! can be variedby density e&g& by press#re changes at constant temperat#re& 2ol#bility

increases in general with press#re #nder s#percritical conditions of themobile phase temperat#re sensitive compo#nds can be processed& Thechromatographic separation can be carried o#t at constant press#re (isobaricoperation" or with increasing press#re (press#re programmed"& 1n additiontemperat#re can be varied& 2-! has one more adj#stable variable foroptimization of el#tion than ! or 3! (,r#nner4556"& . s#percritical $#id has properties similar to a gas and also similar to ali)#id& 7hiledensity and solvent power may be compared to those of li)#ids transportcoe8cients aremore those of a gas& 2-! beca#se of its mobile phase can cover anintermediate regionbetween ! and 3! as ill#strated in -ig#re 4 with respect to density anddi#sioncoeicient& -or preparative and prod#ction scale operations 2-! has theadvantage of easyseparation of mobile phase from separated compo#nds& . disadvantage isthat stronglypolar and ionic molec#les are not dissolved by s#percritical gaseswhich can be advantageo#sly #sed in 2!- (,r#nner 4556"&

-ig& 4& .reas for the dierent mobile phases in chromatographic separationswith respect to component properties (2choenma+ers and 9#n+ 45:;"&

Most gases which can be #sed in 2-! are non'polar& Therefore polars#bstances of a feed mi%t#re can only be el#ted by adding a polar modi0er&

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3Gas Chromatography Application in Supercritical Fluid Extraction Processwhich are easier to handle than ammonia or s#lf#r dio%ide may instead beapplied& To ma+e eective #se of the possibilities of 2-! allowable press#ressho#ld be high&

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4 Applications of Gas Chromatography

!omposition of the mobile phase can s#bstantially in$#ence separation in 2-!(,r#nner4556"& Retention times of s#bstances may be very m#ch dierent d#e topolarity or other physico'chemical properties of the components of the

mobile phase& "investigated large dierences in the separation of aromatic hydrocarbons with!=? @?= !A/: and !A/>&

ases applied in 2-! are mostly non'polar& The polarity of carbon dio%ide at lowdensities is comparable to that of n'he%ane and at higher densities to thatof methylene chloride& @itro#s o%ide and the al+anes b#tane or pentane behavesimilar&

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5Gas Chromatography Application in Supercritical Fluid Extraction Processn#mber of theoretical stages remains nearly constant over a wide rangeof $ow rate& . more detailed disc#ssion of

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Applications of Gas Chromatography

chromatographic f#ndamentals and especially analytical applications of 2-!can be fo#nd in the ab#ndant literat#re on analytical 2-! (ere et al& 45:?B3ee and Mar+ides 455CB 2mith 45::B 7enclawia+ 455?B 7hite 45::"&

The apparat#s (as shown in -ig#re ?" consists of the separation col#mn as centralpart in a temperat#re controlled environment (4" the reservoir for the mobilephase (?" a #nit for establishing maintaining and controlling press#re (A" anoptimal #nit for adding a modi0er (6" the injection part for introd#cing the feedmi%t#re (" a meas#ring device (detector" for determining concentration of theel#ted s#bstances (>" a sample collection #nit (;" a #nit for processing themobile phase (:" and another one for processing data and controlling the totalapparat#s (5" (,r#nner 4556"&

The $ow of the s#percritical gas #nder press#re is maintained by long'stro+episton'p#mps reciprocating piston'p#mps or membrane'p#mps whichdeliver the mobile phase in li)#e0ed form& The fl#id is then heated to

s#percritical conditions before entering the col#mn&

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!Gas Chromatography Application in Supercritical Fluid Extraction Process

n#mber of theoretical stages veri0ed& 2eparations with capillary col#mns can benearly as eective as in gas chromatography& 7hile in early applications steelcapillaries had been #sed in 2-! since 45:C f#sed silica capillary col#mnshave replaced the steel capillaries& 2tationary phases mostly stem from

polysilo%anes and polyglycols& -re)#ently #sed stationary phases have beenlisted in the literat#re (,r#nner 4556"&

9nder conditions of 2-! the compo#nds of the stationary phases may be slightlysol#ble in the mobile phase and are therefore 0%ed by lin+ing them by chemicalreactions& @#mero#s pac+ed col#mns are available many from /C mm inner diameter and >CC mm length with

particles of 4C'? m .l+io et al. (45::" a 5CC mm long col#mn with 6C'A> mdiameter particles&

The length of the col#mn is dependent on the allowable press#re drop&

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" Applications of Gas Chromatography

The #ltraviolet spectroscopy detector (9G" is a nondestr#ctive detectorwhich can be applied at col#mn press#re& 1t is widely #sed b#t islimited to s#bstances with chromophoric gro#ps& 2at#rated hydrocarbonsfatty acids and glycerides may be di8c#lt to detect )#antitatively& These

s#bstances may be detected with a refractive increment detector (R1D" wherethe variation of refractive inde% of the mobile phase ca#sed by dissolveds#bstances is applied for detection& =ther detectors are the $#orescencedetector and the light'scattering detector (,r#nner 4556"&

1n a light'scattering detector the mobile phase is intensively mi%ed with aninert gas and heated while $owing downward a t#be (9pnmoor and,r#nner 45:5B 9pnmoor and ,r#nner 455?"& The inert gas and thetemperat#re increase red#ce solvent capacity of the mobile phase& The el#teds#bstances precipitate and are carried o#t droplets or particles into the detectionchamber& 1nto this chamber a t#ngsten lamp delivers visible light which isdispersed by droplets or particles& The dispersed light is detected by a

photom#ltiplier #nder an angle of >CH& The signal is proportional to the massof light'scattering particles& Therefore the light'scattering detector acts as massdetector and its signal is independent on chromatographic gro#ps& 1t can beapplied for detection of chromatographic and non' chromatographics#bstances in a mi%t#re as for e%ample in fatty acids and glycerides(,r#nner 4556"&

2. Expansion o! mo"ile phase and sample collecting system

1n analytical 2-! the mobile phase is either e%panded after or beforedetection& Downstream to a detector which is operated #nder col#mn

press#re e%pansion can be achieved by normal e%pansion valves& They canact as bac+ press#re reg#lators may be controlled by a central #nit& .tinteresting alternative to an e%pansion valve was designed by 2aito and

Fama#chi who #se time'controlled opening and closing of an #nrestrictedt#be for e%pansion& This has the advantage that bloc+ing of the t#be byprecipitating s#bstances is avoided& .nother e%pansion techni)#e wasadapted from !I . glass capillary is formed into long thin capillary as so'called restrictor&

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#Gas Chromatography Application in Supercritical Fluid Extraction Process

1n preparative 2-! so far mostly e%tracts from plants li+e lemon peel oiltocopherols from wheat germ or #bichinones have been treated& 9nsat#ratedfatty acids from 0sh oil mostly processed as esters is a s#bject investigatedheavily in recent years (Davarnejad et al. ?CC:"&

-ig& A& -low scheme of a preparative 2-! with recycle of the mobile phase(

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$% Applications of Gas Chromatographyill#strated in -ig#re &

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$$Gas Chromatography Application in Supercritical Fluid Extraction Process

-ig& 6& M#ltiposition'valves for injection of samples into a 2-! (,r#nner 4556"&

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$2 Applications of Gas Chromatography

-ig& & !o#pling of 2-E with 2-!& !oncentration of compo#nds in acollecting col#mn(Fama#chi and 2aito455C"&

.ccording to this type of apparat#s some e%amples in details have been shownby ,r#nner(4556"&

. General gas chromatography apparatus

The obtained prod#cts from vario#s types of s#percritical apparat#ses(s#ch as phase e)#ilibri#m and rate test apparat#s" sho#ld be analyzed&/owever dierent types of analyzer can be #sed b#t the conventional !with a s#itable col#mn has widely been recommended& .ltho#gh severalcol#mns for detecting a lot of components have been designed andfabricated by some companies b#t d#e to lac+ing of s#itable col#mns forsome components or #nclear pea+s obtained from some col#mns an e%traprocess (s#ch as esteri0cation of the fractionated 0sh oil" before ! analyze isre)#ired& 1n this application the samples obtained from the s#percritical

e%traction apparat#s are not #nder press#re or their press#res have bro+endown by a damper (in the online !"&

2ince this type of apparat#s has been e%plained in detail in the other chapterstherefore an e%ample from its application is ill#strated in this section&

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$3Gas Chromatography Application in Supercritical Fluid Extraction Process

.1 &riacylglycerols analysis

.1.1 Introduction

Most of the fatty acids of palm oil are present as triacylglycerols (T.s"&

The dierent placements of fatty acids and fatty acid types on the glycerolmolec#le prod#ce a n#mber of dierent T.s& .bo#t ; to 4C percent ofsat#rated T.s are predominantly tripalmitin (Karles+ind and 7olff 455>"and the f#lly #nsat#rated triglycerides constit#te > to 4? percent(Karles+ind and 7ol 455>B Ki$i 45:4"& The T.s in palm oil are partiallyde0ned most as of the physical characteristics of the palm oil s#ch asthe melting point and crystallization behavior (2ambantham#rthi et al.?CCC"& Detailed information abo#t Malaysian tenera palm oil T.s have beengiven in vario#s references (2ambantham#rthi et al. ?CCCB Kifli 45:4B 2ow45;5"& -ato#h et al. (?CC;" st#died the s#percritical e%traction of T.s fromb#alo b#tter oil #sing carbon dio%ide solvent& They concl#ded that increasing

the press#re and temperat#re of the e%traction led to increasing the solvatingpower of the s#percritical carbon dio%ide& 1n these st#dies the T.s weree%tracted d#ring the early stage of the fractionation thereby creating low'melting fractions& !onversely T.s were concentrated in the fractions (i&e&high'melting fractions" obtained towards the end of the process&

.ccording to the literat#re mole fraction sol#bility data of p#re triacylglycerols in!=? were reported at temperat#res of 6C >C and :C H! in the range of 4C '4C to4C'? (2oares et al. ?CC;"& These data depended on the type of triacylglycerolsand operating press#re& That means high press#re had a good eect onsol#bility of triacylglycerols in !=?& -#rthermore tricaprylin had the highersol#bility in !=? (aro#nd 4C'? at high press#res" than the rest (ensen and

Moller#p 455;B ,amberger et al. 45::B 7eber et al. 4555"&

1n this research phase e)#ilibri#m of T.s from cr#de palm oil in s#band slightly s#percritical !=? is st#died& -or this p#rpose the samplesobtained from the phase e)#ilibri#m s#percritical fl#id e%traction apparat#sare caref#lly analyzed by a /

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$4 Applications of Gas Chromatography

-or T.s analysis the following stages are carried o#t step by step #sing a/

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$5Gas Chromatography Application in Supercritical Fluid Extraction Process

Pre""ure#MPa$

TN:C

H!

L!%u!d&ha"e' CO()o*e fra+,!on

-a&or&ha"e' CO()o*e fra+,!on

4C&: C&5 4

;&C C&5 4

?&; 4 4

4&; 4 4

TN4CC H!

44&4 4 4

;&> 4 4

>&4 4 4

4&4 4 4TN4?C H!

;&6 C&5 4

&6 C&5 4

A&A 4 4

C&> 4 4

Table 4& Two'phase e)#ilibri#m calc#lated data based on !=? at :C4CC and4?C H! in order to

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Pre""ure#MPa$

TN:CH!

L!%u!d&ha"e' CO()o*e fra+,!on

-a&or&ha"e' CO()o*e fra+,!on

4C&: C&5 4

;&C C&5 4

?&; 4 4

4&; 4 4

TN4CCH!

44&4 C&5 4

;&> 4 4

>&4 4 44&4 4 4

TN4?CH!

;&6 C&5 4

&6 C&5 4

A&A 4 4

C&> 4 4

Table A& Two'phase e)#ilibri#m calc#lated data based on !=? at :C4CC and

4?C H! in order to 2== analysisThe mole fractions of !=? in the e)#ilibri#m s#percritical e%traction of the

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The mole fractions of !=? in the e)#ilibri#m s#percritical e%traction of the 2==s#bstance for the li)#id and vapor phases are shown in Table A& The 2==s#bstance mole fractions in

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the vapor phase increased with increasing the press#re at :C H!B thistrend was also observed in the li)#id phase& . reg#lar trend was notobserved in the vapor and li)#id phases at 4CC H! and 4?C H!& 2ince 2== alsois from T.s gro#p this s#bject is reasonable as it was legitimized for

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,r#nner & (4556"& as E%tractionI an 1ntrod#ction to -#ndamentals of2#percritical -l#ids and the .pplication to 2eparation &

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dio%ide asmobile phase". )igh *esolution Chromatography Gol& 44 @o& 4C pp& ;64';6A&

2aito M& Fama#chi F& 1nomata K& Kott+amp 7& (45:5"& Enrichment oftocopherols in

wheat germ by directly co#pled s#percritical $#id e%traction with semi'

preparative s#percritical chromatography". Chromatographic !cienceGol& ?; @o& ? pp& ;5':&

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2aito M& Fama#chi F& (455C"& 1solation of tocopherols from wheat germ oil byrecycle semi' preparative s#percritical $#id chromatography ".Chromatography A Gol& C @o&4 pp& ?;'?;4&

2choenma+ers "& Eect of press#re onretention in s#percritical fl#id chromatography with pac+ed col#mns".Chromatography A Gol&A? pp& A4'A?:&

2ambantham#rthi R& 2#ndram K Tan F&.& (?CCC"& !hemistry andbiochemistry of palm oil Progress in 'ipid *esearch Gol& A5 @o& > pp&C;':&

2choenma+ers &9pnmoor D& ,r#nner & (45:5"& Retention of acidic and basic compo#ndsin pac+ed

col#mn s#percritical $#id chromatography Chromatographia Gol& ?: @o&5'4C pp&665'66&

9pnmoor D& ,r#nner & (455?"& C&

7eber 7&

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on !upercritical Fluids&Fama#chi F& 2aito M& (455C"& -ractionation of lemon'peel oil by semi'

preparative s#percritical $#id chromatography ". Chromatography AGol& C @o& 4 pp& ?A;'?6>&

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2

Interaction Parameters o! Sur!actant(ixtures "y In)erse Gas Chromatography

Ele#terio 3#is .rancibia4

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455?" has allowed the determination of reliable polymer'polymer interactionparameters by 1!& /#angPs later proposal (/#ang ?CCAa ?CCAb" based on amethodology similar to the latest

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$" Applications of Gas Chromatography

has been applied to several systems and has been compared with the previo#smethodology #sing retention data in polymer materials (,enabdelghani et al&?CC>"&

1n the case of li)#id crystals they have been thoro#ghly investigated asstationary phases by gas li)#id chromatography (3!" from an analyticalpoint of view (anini et al& 45;B anini et al& 45:CB Martire et al& 45>:"&

They have also been #sed in st#dies of sol#tion thermodynamic by inversegas chromatography (1!" of sol#tes in li)#id crystals (!3" and in polymer li)#idcrystals (!3B -lory 45:6"& The treatment of the dataobtained via 1! in order to get thermodynamic properties #sing -loryPs classicmodel has been more fre)#ently applied to mesophases than to -loryPs li)#idcrystal model& 1n the derivation of this model the e%pression thatcorresponds to the non'combinatory contrib#tion has been discarded (.be V-lory 45;:B -lory V .be 45;:"B th#s the interaction parameter 4? betweenprobe sol#te and stationary phase that represents the energy e%change ofinteractions has not been incl#ded& This might be one of the reasons beca#sethe interaction parameter is obtained preferably by -loryPs classic model ofpolymers&

2ince the probe sol#te is at near in0nite dil#tion the order of the li)#id crystalphase is not destroyed by the probe sol#te incl#sion& The accessibility ofthe probe molec#les in a mesophase co#ld be limited by its ordering& Thismeans that the main interaction occ#rs with the hydrocarbon chains of thebilayers and the interactions are mainly of dispersive character& 7e canestimate the degree of interaction sol#te O stationary phase by -lory/#gginsP interaction parameter obtained by 1! #sing s#rfactants as stationaryphase&

The amphiphilic molec#lar str#ct#re of s#rfactants has a signi0cant in$#ence inthe crystals phase str#ct#re& The pac+ing of the s#rfactants is prod#ced so thatthe liphophilic gro#ps of the dierent molec#les are associated with every

lipophilic region& Their hydrophilic gro#ps are e)#ally associated within the polarregion& 1n this way they form the so called bilayers which are #s#ally formedin crystals of simple or do#ble hydrocarbon chain s#rfactants& 2omes#rfactant crystals do not melt in a li)#id phase directly b#t go thro#ghanhydro#s li)#id crystal phases (thermotropic li)#id crystals" before reaching theisotropic li)#id state& The li)#id crystals of anhydro#s s#rfactants arethermotropic since they res#lt only from the temperat#re increase on anhydro#scrystals (3a#ghlin 4556"&

This chapter is part of a series of wor+s done in this laboratory where severals#rfactant properties s#ch as sol#bility parameters s#rfactant's#rfactantinteraction parameters in several systems made #p by cationic s#rfactants ofdierent hydrocarbon length chain have been determined by 1! (,ardavid etal& ?CCA ?CC;B

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$#&nteraction Parameters of Surfactant 'ixtures (y &n)erse Gas Chromatographyprod#ct performance& -or s#rfactant mi%t#res the characteristic phenomenaare the formation of mi%ed monolayers at the

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2% Applications of Gas Chromatography

interface and mi%ed micelles in the b#l+ sol#tion& 1n s#ch sol#tions adsorptionbehavio#r aggregatesP microstr#ct#re and rheological properties can bemanip#lated to tailor the properties of the dierent prod#cts&

1n ionic anhydro#s s#rfactant systems the str#ct#res of li)#id crystals andcrystals are based on the sim#ltaneo#s f#l0llment of two +inds ofinteractionsI van der 7aals interactions in the hydrocarbon bilayers andthe electrostatic interactions in the ionic bilayers& 2ometimes stericinteractions can appear in the hydrocarbon bilayers and polar interactions orhydrogen bonds can appear in the ionic bilayers (2ch#lz et al& 455>"& .combination of these interactions can be especially disclosed in mi%edamphiphiles systems and their st#dy can lead to a better #nderstanding of theirin$#ence in the formation and stability of the microstr#ct#res mentioned above&

The cationic s#rfactants mi%ed systems are becoming more important and inthe f#t#re additional comple% form#lation a and m#ltiple technological prod#cts

will be re)#ired& The e%tension to a thermodynamic appro%imation ofm#lticomponents incl#ding additional phenomena li+e sol#bility will allow theestablishment of more comple% systems (/olland V R#bingh 455C"& There is notm#ch information abo#t st#dies of cationic s#rfactant mi%t#re phases (Garadeet al& ?CC:" or the miscibility of p#re s#rfactant mi%t#res (,ardavid et al&?CC; ?C4C" that allow resemblance to the behavio#r of s#rfactant mi%t#resinteractions in mi%ed micelles&

1n this chapter we present the res#lts obtained from the st#dy of miscibilityof cationic s#rfactant mi%t#res of three systems made #p by mi%t#res ofs#rfactants of e)#al polar head and dierent hydrocarbon chains bydetermining s#rfactant's#rfactant interaction parameters thro#gh 1!& The

implementation of this techni)#e has also allowed #s to analyze the #se oftwo methodologies of meas#rement in order to obtain the parameter ,?A forcationic s#rfactants and to contrast them with the ones obtained in polymericmaterials& 7ith this wor+ we hope to enlarge the information abo#t thebehavio#r of p#re s#rfactant mi%t#res and analyze the non'ideality degree inthe mi%t#res and its possible ca#ses&

2. Experimental

2.1 (aterials

Dodecylpyridini#m chloride (D

bromide (DD.," and Dioctadecyldimethylammoni#m bromide (D=D.,"(2igma analytical grade 92." were #sed as received& .ll probe sol#tes werechromatographic )#ality or reagent grade and were #sed witho#t f#rtherp#ri0cation&

2.2 Di!!erential Scanning Calorimetry *DSC+

D2! was performed on a calorimeter between ?5A and

?A K with a scanning rate of 4C degree minW4 and #sing samples of O4C mgfor p#re s#rfactants and 4CO4 mg for materials collected over chromatography s#pport& The instr#ment wascalibrated with indi#m&

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2$&nteraction Parameters of Surfactant 'ixtures (y &n)erse Gas Chromatography

2. In)erse Gas Chromatography *IGC+

C:C which was employed as solids#pport& The col#mn 0ller was prepared #sing methanol as a solvent in arotary evaporator #nder a $ow of dry nitrogen and was +ept in a dryatmosphere before 0lling the col#mns (stainless steel pipes"& The col#mn wasloaded and conditioned for 4 h at A>A K #nder a $ow of carrier gas& Theamo#nt of stationary phase on the s#pport was determined by calcinationsof abo#t one gram of material& The data employed in the specific retentionvol#me comp#tation were obtained by #sing a col#mn 4CC cm long 46inch e%ternal diameter and the pac+ing characteristics are incl#ded in Table 4&

2ystem DD., (?" O D=D., (A"

2tationary phase Mass pac+ing 3oading(ww" 7eight fraction

(g" (J" (w?"DD., (?" X D=D., (A" ;&?>A 5&4? C&CCCC

DD., (?" X D=D., (A" ;&>6A? 5&?? C&4>6A

DD., (?" X D=D., (A" ;&:>A6 5&?A C&A?:4

DD., (?" X D=D., (A" ;&C?>: 5&A C&CA;

DD., (?" X D=D., (A" ;&C5C> 5&>C C&;A?

DD., (?" X D=D., (A" ;&::> 5&44 4&CCCC

2ystem D

2tationary phase Mass pac+ing 3oading(ww" 7eight fraction

(g" (J" (w?"

D

D ;&;? C&A6>4

D56 ;&6? C&6C5

D

D

2ystem DT., (?" O =T., (A"

2tationary phase Mass pac+ing 3oading(ww" 7eight fraction

(g" (J" (w?"

DT., (?" X =T., (A" ;&?AC4 4C&C5 C&CCCC

DT., (?" X =T., (A" >&;56; 4C&C6 C&44C?DT., (?" X =T., (A" ;&6?6C 4C&C? C&A>?

DT., (?" X =T., (A" ;&A?:4 5&55 C&5>A

DT., (?" X =T., (A" ;&?A5? 44&>6 C&:AA4

DT., (?" X =T., (A" ;&C;6> 4C&CA 4&CCCC

Table 4& !ol#mn loading data and the weight fraction at the dierent mi%t#res&

The retention time meas#rement for each sol#te was performed with a /ewlet:5C series ! 2ystem e)#ipped with a $ame ionization detector (-1D"& !ol#mn

temperat#re was meas#red in a range between A6A&4 and 6CA&4 K with an 1ron'!onstantan thermoco#ple

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g s

22 Applications of Gas Chromatography

placed in the direct environment of the col#mn& The temperat#re stability d#ringe%periments was Y C&? K& The employed sol#tes were n'he%ane n'heptane n'octane n'nonane cyclohe%ane methylcyclohe%ane benzenetol#ene ethyl acetate dichloromethane trichloromethane and carbon

tetrachloride& @itrogen was #sed as carrier gas&-low rates were meas#red at the beginning of each e%periment with an air'

jac+eted soap 0lm $owmeter placed at the o#tlet of the detector& 1nletpress#res were meas#red with a micrometry syringe (tro#gh the injectorsept#m" which was connected to an open branch merc#ry manometer& Toens#re that the res#lts were independent of sample size and $ow rate andthose meas#rements were being made at in0nite dil#tion the #s#al chec+swere made (!onder V Fo#ng 45;:"& 2ol#tes were injected with 4C Zl /amiltonsyringes as steam in e)#ilibri#m with p#re li)#id& -or all the sol#tes and for allthe range of stationary phase concentrations the pea+s were symmetric& Theinjector was +ept at 6?A K and the detector at

6AK&

Retention times (tR" were meas#red with a !hem 2tation system and theretention speci0c vol#mes (G Cg " were calc#lated with the following relationship(!onder V Fo#ng 45;:"I

5C

=6Ff

?;A&4

(tt )

(pC p ) (4"g $ * C p f C

where j is the ames'Martin compressibility correction factor pCrepresents the o#tlet col#mn press#re -f is the $ow rate meas#red atpress#re pC and temperat#re Tf w is the mass of the stationary phase into thecol#mn and pw is the water vapo#r press#re at TfB tC is the dead time whichwas meas#red by #sing the methane pea+ obtained with the -1D&

. Data reduction

2peci0c retention vol#mes were 0tted to the e)#ation (!onder VFo#ng 45;:"I

ln5

C

=)C

*$ +constan t (?"

where /s is the sorption heat& The val#es obtained for /s as well as theirrespective standard deviations were calc#lated #sing Mar)#artd'3evenbergPsalgorithm (Mar)#artd45>A" and can be seen in Table ?& Gal#es of standard deviations in /s smallerthan 4& J are obtained in the regression of specific retention val#es vs& 4Taltho#gh most of the val#es were near 4&C J&

The meaning of /s depends on the physical state of the stationary phase& -or asolid /s correspond to the molar adsorption enthalpy& -or the li)#idmesophase it was ass#med that the sol#te is dissolved in the stationary phaseso /s corresponds to the molar sol#tion enthalpy&

The average per cent error val#es /s for DDD., is C&:: % and C&;6% forD=D.,& -or the D

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23&nteraction Parameters of Surfactant 'ixtures (y &n)erse Gas Chromatography/s val#es is generally bigger than the previo#s ones and from the calc#latedval#es we get a val#e of 4&A: % for the average error in DT., and of 4&4C %forthe val#es in =T.,&

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2ystem DDD.,'

DDD., D=D.,

/s /s Dierence

n'/e%ane ?:&; C&A AC&; C&A ?&Cn'/eptane AA&6 C&6 A6&: C&6 4&6

n'=ctane A:&> C&? A5&A C&A C&;

,enzene AA& C&? AA&; C&6 C&?

Tol#ene A;& C&6 A;&> C&? C&4

!yclohe%ane ?5&: C&6 A4&4 C&? 4&A

Methylcyclohe%ane AA&> C&? AA&> C&? C&C

Dichloromethane AA&? C&A A?&A C&A 'C&5

Trichloromethane 6A&: C&6 6A&6 C&? 'C&6

!arbon tetrachloride A& C&? A6&A C&? '4&?

Ethyl acetate AA&A C&A A?&> C&4 'C&;2ystem D C&? A4&: C& '4&:

n'=ctane A:&4 C&? A&5 C&6 '?&?

,enzene A?&5 C&A AC&? C&A '?&;

Tol#ene A;&A C&? A&4 C&> '?&>

!yclohe%ane ?5&: C&? ?;&? C&6 '?&>

Methylcyclohe%ane A?&? C&A AC& C& '4&;Dichloromethane A4&6 C&6 ?;&4 C&? '6&A

Trichloromethane 6C&6 C&A A&5 C&A '6&

!arbon tetrachloride AA&5 C&A A4&6 C&? '?&

Ethyl acetate A4&> C&6 ?:&> C&A 'A&C

2ystem DT.,'=T.,

DT., =T.,

/s /s Dierencen'heptano A&C C& AA&4 C&A '4&5

n'=ctano A5&6 C&? A:&6 C&6 '4&C

n'nonano 6A&A C&; 6C&; C& '?&>,enceno A:& C&? A&? C&6 'A&A

Tol#eno 6?&> C&: A5&C C& 'A&>

!yclohe%ane AC&5 C&> ?:&; C&A '?&?

Methylcyclohe%ane AA& C&> A4&A C&6 '?&?

Dichloromethane AA&: C&? AC&: C&A 'A&C

Trichloromethane 6;&? C&: 6A&4 C&6 '6&4

!arbon tetrachloride A6&; C&: A?& C&6 '?&?

Ethyl acetate AA&> C&A ?5&; C&A 'A&5

Table ?& 2ol#tion heat (+&mol'4" and standard deviations for of the s#rfactant

mi%t#res&

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C

.ctivity coef0cients at in0nite dil#tion in terms of mole fraction wereobtained by the following e%pression ("& The sol#te densities at dierent temperat#res were estimated fromDreisbach[s compilation (Dreisbach 45"& The second virial coe8cient of thesol#tes was calc#lated by Tsonopo#los[s correlation #sing critical constantstab#lated in Reid et al& (Reid et al& 45:>"&

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7hen the stationary phase is a s#rfactant mi%t#re E)#ation (;" allows todetermine the ternary probe sol#te (4"'s#rfactant (?"'s#rfactant (A" interactionparameter 4(?A" ass#ming an additive speci0c vol#me for the s#rfactantmi%t#re mNw? ? X wA A where wi is the weight fraction of s#rfactant i inthe mi%t#re (Deshpande et al& 45;6"&

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5

?;A&4D*(? v? +A vA ) pC

(%44 54 ) 5

5

=ln 4 4 4

+ 4 4

(;"4(?A"

5C

pC

5

*$ ?

5

A

5

g 44

? A

where i stands for the vol#me fraction for i component in the stationaryphase& Gi is the molar vol#me of component i in the mi%t#re&

=n the contrary ass#ming the 2cott'Tompa appro%imation (Tompa 45>" whichdescribes a ternary system as a simple balance of the corresponding binarysystems it is possible to calc#late the s#rfactant's#rfactant interactionparameter ?A byI

=

+

54 (:"4(?A" ? 4? A 4A ? A ?A 5?

.s it has been indicated by dierent a#thors the polymer'polymer interactionparameter determined by 1! shows a clear dependence on the solvent #sedas a probe& 1n order to solve this problem dierent methods have beenproposed& The -aroo)#e and Deshpande (-aroo)#e V Deshpande 455?" andthe /#ang (/#ang ?CCAa ?CCAb" methodologies will be applied to retentiondata obtained from the #se of s#rfactant anhidro#s mi%t#res in order to carryo#t a comparative analysis of the behavio#r of these methodologies inthe determination of s#rfactant's#rfactant interaction parameters&

-aroo)#e and Deshpande (-aroo)#e V Deshpande 455?" methodology gives areliable tr#e interaction parameter after a rearrangement of E)& (:"I

4(?A"4A? (4?

4A )

=

?A

(5"

54 54? A

?

. plot of the left side of this e%pression vers#s the 0rst term of the right'hand

side yields a lineal f#nction from whose slope ? can be calc#lated and from theintercept ?A can beobtained& The physical meaning of the slope was interpreted in terms of aneective average col#mn composition that the sol#tes are probing&

/#ang (/#ang ?CCAa ?CCAb"et& al& have proposed an alternative rearrangementof E)&( :"I

4(?A" + =

? 4? A 4A

?A (4C"54 54 ? A 5?

. linear plot can be obtained from the left'hand side vs& first term of right'sideof E)&(4C"allowing that the interaction parameter can beobtained&

1n both methodologies if the conditions given by .l'2aigh and M#n+ (.l'2aighV M#n+

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45:6" are obeyed the s#rfactant's#rfactant interaction parameter can becalc#lated thro#gh the speci0c retention vol#me witho#t calc#lating theindivid#al parameter&

The val#es of the s#rfactant's#rfactant interaction parameters can be analyzedas ?AG? or as ?A when m#ltiplied by G? or as the e)#ivalent )#antity ,?A N RT

(?AG?" (in &cm'A" called energy density&

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#. 'esults and discussion

#.1 Sur!actants as stationary phases

1n this chapter both D2! and 1! were #sed to con0rm the stationary phase

stability with temperat#re& The phase transition temperat#res weredetermined with D2! on p#re s#rfactants between ?5A and ?A K& The sametechni)#e was also employed to analyze the thermal behavio#r of boths#rfactants deposited over the solid s#pport in a 4C J (ww" percentageappro%imately&

!how and Martire (!how V Martire 45;4" compared 1! and D2! st#dies ontwo azo%y li)#id crystals and reported no meas#rable adsorption effects fromthe interface above a 0lm thic+ness of 4CC nm& 7it+iewicz (Rayss & et al&45:C" reported s#rface orientation eects #p to depth of ? nm b#t in a laterwor+ reported constant speci0c retention vol#mes above a stationary phaseloading of above J (Marcinia+ V 7it+iewicz 45:4"& Qho# et al& (Qho# 4556"

in the ! and 1R st#dy of li)#id crystal deposited on dierent types of silicahave shown that for a percentage #nder of ; J of the stationary phase loadingthe ln Gg vs4T plot did not show discontin#ity& The loading #sed in this wor+ was near of4C J on!hromosorb 7 in all thecases&

The retention diagram of ln Gg vs 4T for sol#te probes in D=D., and DD.,coated on !hromosorb 7 @.7 >C:C is shown in -ig#re 4 (,ardavid etal& ?CC;"& -or both s#rfactants speci0c retention vol#mes were obtainedbetween ACA K and 6?A K& =n heating the crystalline solid the retention

decreases #ntil the crystalline solid'to'li)#id crystal transition is reached&Then there is a large increase in retention which once the system phasechange 0nished decreases with increasing temperat#re& -or DD., andD=D., changes in retention are observed at A6A&4 K and A:&4 K respectively&

-ig& 4& The retention diagram for sol#te probes in DD., (a" and D=D., (b"coated on!hromosorb 7& 2ol#tesI (\" tol#eneB (]" carbon tetrachlorideB (^"n'octane&

D2! meas#rements of the phase transition temperat#re for DD., y D=D.,have been described in the literat#re (2ch#lz et al& 4556 455:"& Thee%perimental meas#rements for DD., (,ardavid et al& ?CC;" D2! analysisshows a temperat#re transition between the solid phase and li)#id crystalmesophase thro#gh two pea+s at AA>&: K and A65&? K& These val#es were

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coincident with those obtained in bibliography (2ch#lz et al& 4556"& The0rst pea+

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*emperature+,-

corresponds to the melting of hydrocarbon tails of DD., and that at A65&? Kcorresponds to the melting of the DD., polar heads bilayer giving ananhydro#s lamellar li)#id crystal which in some circ#mstances (i&e& whenlamellae are parallel to the slide s#rface" appears as pse#do'isotropic& There is

another phase transition at 66&5 K that co#ld be the transition to isotropicli)#id& D2! val#es in the literat#re have been informed #p to 66&5 K&

D2! analysis for p#re D=D., shows a phase transition at A>4&: K (,ardavid etal& ?CC;"& .ccording to the literat#re (2ch#lz et al& 4556" this transitioncorresponds to the melting of D=D., crystals to a li)#id which was named apse#doisotropic li)#id (2ch#lz et al& 455:"& 7e have not detected in o#rthermogram the hydrocarbon tails transition temperat#re perhaps beca#seboth transitions (i&e& the melting of the polar and the apolar layer" occ#r atalmost the same temperat#re giving an overlapping of their pea+sB b#t we havedetected another transition temperat#re at 6A5&A K that we considered asthe transition from mesophase to isotropic li)#id& The transitions for DD., and

D=D., in literat#re (2ch#lz et al& 4556 455:" were st#died #p to smallertemperat#res than o#rs& DD., and D=D., s#pported on !hromosorb 7@.7 show a slight displacement toward smaller temperat#res withrespect to p#re s#rfactants& There is previo#s information abo#tdiscrepancies in the res#lts when li)#id and s#pported samples are analyzed byD2! with lower val#es of transition temperat#re for the last ones (2hillcoc+ V&4 K and 4A&4 K for D

(,ardavid et al& ?C44"&1n the case of !

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AA5&4 K for D

7hen the st#died system consists of DT., and =T., either p#re or mi%eddeposited on !hromosorb 7 prod#ced lamellar mesophases at wor+temperat#re (3a#ghlin 455C"& D2! e%periments showed the phase changes fromcrystal to li)#id crystal occ#rring at A;?& K for DT., and at A;:&4 K for =T.,(,ardavid et al& ?C4C"& 1! meas#rements of the retentive behavior of n'octane and tol#ene between AA:&4 and 6?A&4 K indicate (in the ln Gg vs& 4Tplot" retention changes at A>:&4 K for DT., and A;A&4 K for =T.,& The anhydro#scrystal to lamellar phase transition in p#re dodecyltrimethylammoni#mchloride (DT.!" occ#rs at abo#t A>&4 K (,lac+more V Tiddy 455C"& Ta+inginto acco#nt the eect of changing the co#nterion the agreement is good&

The D2! techni)#e is very acc#rate in determining the p#re componentproperties and the 1! res#lts can be #sed as s#pplement to the D2! res#lts inthe case of s#rfactant deposited on solid s#pport& The val#es of transitiontemperat#res obtained by 1! are always lower than those obtained by D2!and even more when the very start detection method is #sed to obtain thetransition temperat#re by means of gas chromatography (,enabdelghani etal&?CC>B @astasovic V =njia ?CC:B 2hillcoc+ V

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et al& 45;6" especially of interaction parameters that play an importantrole in determining the miscibility of

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mi%t#res& The behavio#r of s#rfactant mi%t#res has been determined by 1!allowing the e%perimental determination of s#rfactant's#rfactant interactionparameters in systems with dierent characteristics (,ardavid et al& ?CC;?C4C ?C44"&

@egative val#es of ,?A are indicative of attractive interactions and hence highermiscibility& =n the contrary positive val#es of ,?A wo#ld indicate rep#lsiveinteractions between the two polymers and they are related to immiscibility (.l'2aigh V M#n+ 45:6B ,enabdelghani et al& ?CC>B Deshpande et al& 45;6BDi

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higher temperat#res (,enabdelghani et al& ?CC>"& . similar behavio#r can beobserved in the systems with the s#rfactants st#died&

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#. Faroo%ue,Deshpande and -uang methodology

-aroo)#e and Deshpande (-aroo)#e V Deshpande 455?" and /#angPs(/#ang ?CCAa

?CCAb" methodologies have been shown to be effective and reliable todetermine the interaction parameter ?A in polymers by 1! since theseparameters were )#estioned beca#se of their dependence on the probe sol#tes#sed&

7e have applied the thermodynamic relations determined by 1! for polymermi%t#res to anhydro#s s#rfactant mi%t#res and have proved that the res#ltsobtained show a behavio#r that is coherent among the systems st#died&2imilarly we have proved that the res#lts are coherent with some res#ltsobtained in a)#eo#s sol#tions of cationic s#rfactants& 1tPs worth noting that thee)#ations #sed in the meas#rement of ,?A wo#ld be only valid for misciblemi%t#res altho#gh they have been applied s#ccessf#lly to several

systems that show immiscibility (D# et al& 4555B Qhi+#an V 7alsh45:A"& ,enabdelghani et al& (,enabdelghani et al& ?CC>" have carried o#tan analysis of both methodologies in a st#dy of phase behavio#r ofpoly(styrene'co'methacrylic acid"poly(?>'dimethyl'46'phenylene o%ide"thro#gh 1! of polymer mi%t#res&

They have concl#ded that both methods show similar interaction parameterval#es and that both can be considered as reliable to determine the tr#e polymermi%t#re parameters&

The possibility to co#nt with e%perimental data in three binary systems ofanhydro#s s#rfactants their molar vol#me and to devise a method to classify

miscibility in mi%t#res has led #s to apply both methodologies to s#rfactantmi%t#res& ,esides this allows #s to prove if both methods can be #sed in thesetypes of s#bstances&

1n Table A we have incl#ded the val#es obtained from the intercept itserrors and the correlation coe8cients with the lineal 0tting of the data appliedto the e)#ations (5 and 4C" #sing both methodologies for the system DD., OD=D.,& This system presents positive val#es of ,?A that indicate the presenceof immiscibility in this mi%t#re&

2everal observations can be made on the obtained val#es& -irst the interceptionval#es in this system (DD., O D=D.," are nearly e)#al for both

methodologies& 9sing /#angPs methodology the errors are the do#ble orlarger& The correlation coe8cients of the lineal regression are e%cellent in/#angPs methodologies in contrast to -aroo)#e y DeshpandePs (-'D"(-aroo)#e V Deshpande 455?" which are good&

These res#lts are similar to those obtained from the comparison betweenboth methods made by ,enabdeghani et al& (,enabdelghani et al& ?CC>" inthe system

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val#es are similar and the errors obtained by /#ang are slightly higher&

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A>A&4 K - ' D /#ang

w?(DDD.," ord&4C6 &4C r _ ord&4C6 &4C r _C&4>6A 4:&>6 4&?: C&5;;5 4:&54 A&6C C&5555

C&A?:4 45&5: ?&C C&55C? 45&>4 ?&4 C&5555C&CA; 4:&A6 6&5C C&5;5> 4;&AC >&4 C&555>

C&;A? 4;&C> 6&4 C&55?> 4&C6 A&>A C&555:

.verage A&4: A&5?

A;A&4 K - ' D /#ang

w? ord&4C6 &4C r _ ord&4C6 &4C r _C&4>6A ?4&44 ?&5 C&5?>C ?4&A6 &4> C&555;

C&A?:4 ?A&6 A&44 C&5:4? ?A&64 &4C C&555;

C&CA; ?4&:4 A&:A C&55CC ?C&; >&A4 C&555>

C&;A? ?C&>? 6&>A C&55A4 45&6C >&C C&555>

.verage A&>A &>

A:A&4 K - ' D /#ang

w? ord&4C6 &4C r _ ord&4C6 &4C r _C&4>6A ?&5 4&:C C&5A: ?;&4; ;&4> C&555>

C&A?:4 ?;&:> ?&4? C&55C: ?:&AC &46 C&555:

C&CA; ?>&6; A&:C C&554? ?&?; ;&>: C&555

C&;A? ?6&6: ;&:4 C&5:C4 ?&>: 4A&>5 C&55:4

.verage A&:: :&6?

A5A&4 K - ' D /#ang

w? ord&4C6 &4C r _ ord&4C6 &4C r _C&4>6A A?&5 6&A4 C&::C A&CC :&?6 C&555

C&A?:4 AA&;> A&64 C&5:A A&A? &C5 C&555:

C&CA; AA&A> 6&?4 C&55C> A6&>C ;&C6 C&555>

C&;A? AC&5> >&4? C&554C AA&A6 4C&>4 C&555C

.verage 6&4 ;&;6

6CA&4 K - ' D /#ang

w? ord&4C6 &4C r _ ord&4C6 &4C r _C&4>6A 6C&C A&6: C&:5A> 6?&?: 4?&>6 C&5554

C&A?:4 64&45 &C5 C&5>:6 6?&6 4?&4: C&5554

C&CA; A5&;> >&C5 C&5:6; 6C&66 4A&?6 C&55::

C&;A? A;&6C ;&; C&5::> A5&6A 4:&;? C&55;6

.verage &>C 46&45

Table A& 1ntercepts (ord" standard deviations (" and correlationcoef0cients (r?" in the system DDD., O D=D.,&

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A6:&4 K - ' D /#ang

w?(D

1n /#angPs method the correlation coeicients for all percentages and at alltemperat#res are greater than C&555 and in the method - O D the val#e of thesecoe8cients is between C&5 and C&555&

1n Table the val#es obtained from the intercept their error and correlationcoefficients from the lineal 0tting of the data for the system DT., O =T., areincl#ded& This system presents a partial miscibility in accordance with theval#es of ,?A obtained by - O D the intercept val#es determined by bothmethodologies present major dierences between the systems st#diedB all theval#es determined by - ' D are negative e%cept for the 0rst val#es at the last twotemperat#res&

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A::&4 K - ' D /#ang

w?(DT.," ord&4C6 &4C r _ ord&4C6 &4C r _C&44C? '>&A4 6A&4 C&5;>A 4?&6 :4&?A C&56:

C&A>? '4A&? 6A&?; C&556C C&6 :C&:: C&5>6C&5>A '4&?C 64&C; C&5;6 '?&:4 ;6&?A C&5>A?

C&:AA4 '4A&:5 6&4 C&5?A '4&;? :C&?? C&5>>

.verage 6A&? ;5&46

A5A&4 K - ' D /#ang

w? ord&4C6 &4C r _ ord&4C6 &4C r _C&44C? '4&?C A5&;C C&5;A4 4:&:6 :C&;6 C&56:

C&A>? '5&>? A5&;6 C&556: &;5 ;5&6? C&5;

C&5>A '44&A4 64&4A C&5;A? ?&>> :?&C C&565

C&:AA4 '5&5: 64&:? C&5>A? A&A4 :4&C6 C&5:.verage 6C&>C :C&:4

A5:&4 K - ' D /#ang

w? ord&4C6 &4C r _ ord&4C6 &4C r _C&44C? ?&66 A>&5> C&5;4> ??&5; :4&>6 C&5A>

C&A>? '&;; A>&6 C&5;C 4C&A ;5&: C&5;A

C&5>A ';&:; A:&4C C&5;C ;&: :?&A: C&566

C&:AA4 '&5; A:&6 C&5A>6 :&44 :?&;4 C&56

.verage A;&A :4&:

- ' D /#ang

6CA&4 K ord&4C6 &4C r _ ord&4C6 &4C r _C&44C? &:5 AA&5> C&5>;6 ?>&A :?&C? C&5A6

C&A>? 'A&? A6&;5 C&554A 46&?5 :?&;; C&5A:

C&5>A '&?: A&56 C&5646 4C&:5 :>&?C C&5C>

C&:AA4 'A&C A;&C; C&5;5 4?&4? ::&?> C&56:;

.verage A&66 :6&:4

Table & 1ntercepts (ord" standard deviations (" and correlation

coef0cients (r?" in the system DT.,'=T.,&

1n /#angPs methodology the only negative intercept val#es correspond to thoseof the last two weight fractions at the 0rst temperat#re b#t in thismethodology the val#es show incoherence at the dierent temperat#res& Thehighest errors appear in /#angPs method (close to the do#ble" and thecorrelation coefficients are good and similar in both methodologies (C&56'C&55 in -'D and C&56'C&5> in /#ang"&

1n all systems we can point o#t that the major errors correspond to /#angPsmethodology with a good correlation of the lineal regression in this method&

This behavio#r is similar to that obtained by ,enabdelghani et al&(,enabdelghani et al& ?CC>" in polymers and as

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pointed o#t by these a#thors this co#ld be d#e to the fact that the e%perimentalpoints fitted in /#angPs method are far from the intercept and itsdetermination is s#bject to a major error& The enlargement of the val#esthat correspond to the intercept in /#angPs methodology leads to the

d#plication of errors and to res#lts that are less n#merically stable in relation to-'D methodology&

1t is worth mentioning that besides the intrinsic errors of the chromatographicmethod in the determination of the parameter ?AG? (obtained from a delicatebalance between a ternary system (4(?A"" and two binary systems (4? and4A"" there wo#ld be e%perimental errors of the method as pointed o#t byEt%eberria et al& (Et%eberria et al& ?CCC"& =ne way of red#cing the #ncertainty inthe val#es of ,?A is an ade)#ate selection of probe solvents& 1n this way wehave tried to cover all the possible chemical str#ct#res and polarities avoidingthe tests with similar retention among the retentive possibilities in this type of

s#rfactant& 7e have incl#ded hydrocarbons in the probe sol#tes altho#gh theyare not recommended for the e%perimental determination of polymerinteraction parameters (Et%eberria et al& ?CCC"&

1n Table ? we have incl#ded val#es of sol#tion enthalpies obtained of theretention time data vs& 4T their errors at a level of reliability of 5 J andthe dierences between the val#es of sol#tion enthalpies for each of thesystems st#died& 1n general terms we can point o#t that the system DD., OD=D., presents the slightest dierences between /Hs and the minor erroramong the systems st#died& ,esides both stationary phases wo#ld show amajor apolar character d#e to the major density of hydrocarbon chain& Theother two systems present similar val#es of sol#tion heat and the highest val#esin the component with a minor hydrocarbon chain&

7e have calc#lated the average errors in the sol#tion heat of the systemsst#died which are also incl#ded in Table ?& Th#s we can observe that thesystem DD., O D=D., presents a minor average error in the sol#tion heat ofC&:4 J the system D

dierence in the errors obtained from a retention time correlation as a f#nction of4T&

7e have observed that in the res#lts determined in the three systems by/#angPs methodology (/#ang ?CCAa ?CCAb" the val#e of the slope shows thatwhen the withdrawal from the #nit is greater the dierence between theintercept val#es is bigger in both methodologies&

1n Table > we have incl#ded the val#es obtained from the dierences betweenthe intercept val#es determined by both methods in the systems st#died andthe slope calc#lated by /#angPs methodology for the 0rst val#es oftemperat#re&

.s it can be seen in Table > the highest val#es of the differences betweenintercept val#es are visible when the deviation of the slope from the #nit ismajor& 7e have plotted the val#es of the dierences between the ordinateval#es in the method -'D (-aroo)#e V Deshpande 455?" and in /#angPsmethodology (/#ang ?CCAa ?CCAb" as a f#nction of the

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slope determined by /#angPs method& -ig#re A shows that in the systemsDD.,'D=D., and D

C&4>6A 4:&> 4:&5 ' 4&CC

C&A?:4 45&5 45&> C&A 4&CC

C&CA; 4:&A 4;&A 4&C 4&C4

C&;A? 4;&C 4&C ?&C 4&C?

D

C&45: 5&6 6&5 6&6 4&CA

C&A6>4 :&6 A&4 &A 4&C6

C&6C5 :&> A& &4 4&C6

C&;5C 4?&C 4C&4 4&5 4&C4

DT.,'=T.,

A::&4 K =rd&4C

w? -'D /#ang Dierence /#ang slope

C&44C? ' 4?&6 ' C&:5C

C&A>? ' C&6 ' C&:5CC&5>A '4&?C ' ' C&:;5

C&:AA4 '4A&:5 ' ' C&:>

Table >& Differences of the val#es between the intercept val#esdeterminate by both methodologies and the slope calc#lated by /#angPsmethodology&

The dots corresponding to the system DT.,'=T., are in a part of the graphopposite to the val#es fo#nd in the other two systems& 1n this system it canbe observed the higher dierences between the ordinate val#es the major

errors in both methodologiesB the errors in /#angPs method are twice as big asthose fo#nd in -'D the correlation coe8cients are similar and the slopes in/#angPs method are minor than the #nit&

1n general terms we can point o#t that the -'D method is n#merically morestable than /#angPs methodology in these systems& This wo#ld be d#e to thealgebraic treatment of the depart#re e%pression& The higher val#es of thecorrelation coeicient in the regression are the res#lt from the scale e%pansionin /#angPs methodology&

.s a concl#sion in these systems the res#lts of the comparison between themethodologies are in agreement with what ,enabdelghani et al&

(,enabdelghani et al& ?CC>" said& 7e also fo#nd that when the val#e ofwithdrawal of the slope from the #nit in /#angPs method is higher the val#esare less reliable and there are higher errors than in the method of -'D&

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-ig& A& Dierences between the ordinate val#es in the method -'D andin /#angPs methodology as a f#nction of the slope determined by/#angPs method&

. Conclusions

The st#died systems were different mi%t#res of anhydro#s cationic s#rfactantsdeposited on solid s#pport that has been #sed as stationary phases in 1! andthe res#lts were analyzed in term of mi%t#res miscibility&

The determination of the thermodynamic miscibility was realized by theval#es of s#rfactant's#rfactant interaction parameters obtained by thesame method #sed in polymeric materials&

The comparative #se of two phenomenological methodologies allowed #s tocalc#late the s#rfactant's#rfactant interaction parameter in anhydro#s cationics#rfactant mi%t#resB the obtained res#lts were similar to those obtained by,enabdelghaie et al& (,enabdelghani et al& ?CC>" in polymeric materials&

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7e also fo#nd that when the val#e of withdrawal of the slope from the #nit in/#angPs method is higher the val#es are less reliable and there are majorerrors than in the method of -'D&

/. Ac0noledgments

This wor+ was sponsored by !19@T (!onsejo de 1nvestigaciones de la9niversidad @acional de T#c#m`n" and partially by 9@2& E&3&.& is a memberof !=@1!ET (!onsejo @acional de 1nvestigaciones !ient0cas y Tcnicas de laRep#blica .rgentina"&

. 'e!erences

.be .& V -lory ;:'>:6

,ardavid 2& M& 2ch#lz "&The phase behavio#r of poly(styrene'co'methacrylic acid"poly(?>'

dimethyl'46'phenylene o%ide" by 1nverse as !hromatography& ".Chromatog. A 44?; ?A;'?6

,hat M& .& Dar .& .& .min .& Rashid

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Thermodynamic interactions in polymer2ystems by as'3i)#id'!hromatography& 1G&

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1nteractions between components in a mi%ed stationary phase&&acromolecules; AC'A&

Di

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-lory

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/#ang & !& (?CCAa"& .nalysis of the thermodynamic compatibility of poly(vinylchloride"

and nitrile r#bbers from 1nverse as !hromatography&". Appl. Polym. !ci.:5 4?6?'

4?65/#ang & !& (?CCAb"& Determination of polymer'polymer interactionparameters #sing

1nverse as !hromatography&". Appl. Polym. !ci. 5C >;4'>:C/#ang & !& !oca & V 3anger 2& /& (?CC;"& 3i)#id crystal sol#tions at in0nite

dil#tionI 2ol#te phase transfer free energy and sol#bility parametervariations at phase conversion temperat#res. Fluid Phase E-uili. ?A6?'6;

anini & M& ohnston K& V Qielins+i 7& 3& r& ( 45;"& 9se of a nematic li)#idcrystal for

gas' li)#id chromatographic separation of polyaromatic hydrocarbons&

Anal. Chem.6; >;C' >;6

anini & M& Manning 7& ,& Qielins+i 7& 3& r&V M#schi+ M& (45:C"&as'li)#id chromatographic separation of bile acids and steroids on anematic li)#id crystal&". Chromatogr. 45A 666'6C

3a#ghlin R& & (455C"& Cationic !urfactants A"& .n .lgorithm for 3east'2)#ares Estimation of@onlinear

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s#rfactants& Colloids and !urf. A, Physicochem. Eng. Aspects ?46 4>;'4;4

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Rayss & 7it+iewicz Q& 7a+sm#ndz+i .& V Dabrows+i R& (45:C"& Effect of thes#pport s#rface on the str#ct#re of the 0lm of li)#id crystallinestationary phase& ". Chromatgr. A., 4:: 4C;'44A

Reid R& !& 6C' 4>646

2ch#lz

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polymer'polymer interaction parameter by an improved 1nverse as!hromatographic approach& Polymer 6? 4C;'4C:4

Qhi+#an !& V 7alsh D& & (45:A"& 1nverse as !hromatography for the st#dy ofone phase

and two phase polymer mi%t#res& Eur. Polym. ". 45 45' ?6

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Qho# F& 7& aroniec M& /ann & 3& V ilpin R& K& (4556"& as!hromatographic and 1nfrared st#dies of 6P'cyano'6'biphenyl 6'(6'pentenylo%y"benzoate coated on poro#s silica&Anal. Chem& >> 466'46:

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Applications o! Chromatography -yphenated&echni%ues in the Field o! 3ignin Pyrolysis

2h#bin 7# aojin 3v and R#i3o# !outh China University of

$echnology, China

1. Introduction

D#e to the #rgency of the c#rrent world energy s#pply'and'demand sit#ation theneed for clean so#rces of energy is receiving an increasing attention& 1n theframewor+ of a f#t#re s#stainable development biomass is one of the mostoften considered so#rces of renewable energy (,ridgewater et al& 4555"& Thereare many ways of converting biomass into #sef#l prod#cts and energy s#chas direct comb#stion processes thermochemical processes biochemicalprocesses and agrochemical processes etc& =f these pyrolysis forms the foc#sof this st#dy (,ridgewater ?CC6B Mohan et al& ?CC>"& The pyrolysis oflignocell#lose is very comple% primarily d#e to the inherent comple%ity ofthe s#bstrate which changes contin#o#sly both chemically andstr#ct#rally thro#gho#t the decomposition process (/osoya et al& ?CC;B 3v et

al& ?C4Ca"&The chemical str#ct#re and major organic components in biomass are e%tremelyimportant in biomass pyrolysis processes& Knowledge of the pyrolysischaracteristics of the three main components is the basis and th#sessentially important for a better #nderstanding of biomass thermalchemical conversion& 3ignin is one of the main components of woodybiomass and the worldwide prod#ction of technical lignins as a by'prod#ct fromchemical p#lping processes stands at appro%imately C million tyr (/ar#mi etal& ?C4C"& /owever it is merely #sed as f#el to recover energy in conventionalp#lping ind#stry& =nly recently with the #pcoming foc#s on biore0nerieslignin has gained new interest as chemical reso#rces&

.nalytical pyrolysis is a well'+nown techni)#e to analyse lignin pyrolysis andvario#s a#thors p#blished dierent analytical methods to determinedecomposition characteristics of lignin& Many researchers presented that thepyrolysis of lignin primarily occ#rred in a wide temperat#re range (?CC'>CCo!" by means of thermogravimetric analysis method (Domng#ez et al&?CC:B 3v et al& ?C4Cb"& 2ome researchers (3i# et al& ?CC:B 7ang et al&?CC5" also compared the pyrolysis behavior of lignin from dierent treespecies #singthermogravimetryO-o#rier transform infrared spectroscopy (TO-T1R"&

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42 Applications of Gas Chromatography

=n lignin pyrolysis their prod#ct analysis and f#rther deriving the crac+ingmechanism many researchers have done considerable wor+s& -or e%ample,a#mlin et al& (?CC>" have reported the res#lts of e%periments performed onthe flash pyrolysis of two types of lignins i&e& +raft lignin and organocell lignin

to prod#ce hydrogen& @owa+ows+ia et al& (?C4C" presented an internationalst#dy of fast pyrolysis of lignin& egers and Klein (45:" had reported thatvario#s catechol (4?'dihydro%ybenzene" o'cresol (?'methylphenol" and otherphenols prod#cts go along with the formation of g#aiacols d#ring the co#rse oflignin pyrolysis the yields of those prod#cts are dierent corresponding to thedierent +inds of lignin and pyrolysis conditions& .ccording to ,ritt et al&(455" lignin pyrolysis occ#rred mainly by a free'radical reactionmechanism& The relative distrib#tion of prod#cts is dependent on pyrolysisconditions s#ch as so#rces of raw materials pyrolysis temperat#re heatingrate pyrolysis atmosphere and catalyst etc& (arcia et al& ?CC:"&

To s#m #p there have already emerged lots of st#dies abo#t lignin pyrolysisand their foc#s and concerns were also varied& ,#t so far to o#r +nowledge

limited information is available in the literat#re concerning the prod#ctgeneration and distrib#tion reg#larities of lignin pyrolysis #nder thein$#ence of parameters li+e temperat#res and catalysts& Therefore theobjectives of this wor+ were to attempt to carry o#t fast pyrolysis of severallignin samples (one enzymaticmild acidolysis lignin and two technical ligninswere #sed" and analyse the prod#cts by

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43Applications of Chromatography yphenated *echniues in the Field of ignin Pyrolysis

#ses of ! incl#de testing the p#rity of a partic#lar s#bstance or separating thedierent components of a comple% mi%t#re s#ch as bio oil&

7hen #sed to prepare p#re compo#nds from a mi%t#re ! can separatethe volatile components of mi%t#res by dierential migration thro#gh a col#mncontaining a li)#id or solid stationary phase (-# ?CC:"& 2ol#tes are transportedthro#gh the col#mn by a gaseo#s mobile phase and are detected as they areel#ted& 2ol#tes are generally el#ted in order of increasing boiling point e%ceptwhere there are speci0c interactions with the stationary phase& .n elevatedtemperat#re #s#ally in the range C'ACo! is normally employed to ens#rethat the sol#tes have ade)#ate volatility and are therefore el#ted reasonably)#ic+ly&

2.1.2 Identi!ication

Mass spectrometry (M2" is an analytical techni)#e in which gaseo#s ions formed

from the molec#les or atoms of a sample are separated in space or time anddetected according to their mass'to'charge ratio mz (2par+man ?CCC"& 1t is#s#ally #sed for determining masses of particles for determining theelemental composition of a sample or molec#le and for el#cidating thechemical str#ct#res of molec#les s#ch as phenols aldehydes and otherchemical compo#nds&

The M2 principle consists of ionizing chemical compo#nds to generate chargedmolec#les or molec#le fragments and meas#ring their mass'to'charge ratios&

The n#mbers of ions of each mass detected constit#te a mass spectr#m& Thespectr#m provides str#ct#ral information and often an acc#rate relativemolec#lar mass from which an #n+nown compo#nd can be identified or a

str#ct#re confirmed&

2.1. Com"ination

as chromatography'mass spectrometry (!'M2" is a common combinedtechni)#e comprising a gas chromatograph (!" co#pled to a massspectrometer (M2" by which comple% mi%t#res of chemicals may beseparated identi0ed and )#anti0ed& . schematic diagram of a !'M2 isshown in -ig& 4& 1n this techni)#e a gas chromatograph is #sed to separatedifferent compo#nds& This stream of separated compo#nds is fed onlineinto the ion so#rce a metallic filament to which voltage is applied& This 0lamentemits electrons which ionize the compo#nds& The ions can then f#rtherfragment yielding predictable patterns& 1ntact ions and fragments pass intothe mass spectrometer[s analyzer and are event#ally detected (.dams ?CC;B3ee V E#gene ?CC6"&

This ma+es it becoming an ideal tool of choice for the analysis of the h#ndreds ofrelatively low molec#lar weight compo#nds fo#nd in biomass pyrolysis li)#idprod#cts (bio oil"& 1n order to ma+e a compo#nd be analysed by !'M2 itm#st be s#8ciently volatile and thermally stable& 1n addition f#nctionalisedcompo#nds may re)#ire chemical modification (derivatization" prior to analysisto eliminate #ndesirable adsorption eects that wo#ld otherwise aect the)#ality of the data obtained (7# ?CC"& ,io oil samples are #s#ally needed

to be solvent e%tracted and dehydrated before !'M2 analysis&The prepared sample sol#tion is injected into the ! inlet where it is vaporizedand swept into a chromatographic col#mn by the carrier gas& The sample$ows thro#gh the col#mn and the compo#nds comprising the mi%t#re ofinterest are separated by virt#e of their

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44 Applications of Gas Chromatography

-ig& 4& 2chematic of a !'M2system

relative interaction with the coating of the col#mn (stationary phase" and thecarrier gas (mobile phase"& The latter part of the col#mn passes thro#gh aheated transfer line and ends at the entrance to ion so#rce (-ig& 4" wherecompo#nds el#ting from the col#mn are converted to ions& Then the ions areseparated in a mass analyser (0lter"& .fter that the ions enter a detector theo#tp#t from which is ampli0ed to boost the signal& The detector sendsinformation to a comp#ter that records all of the data prod#ced convertsthe electrical imp#lses into vis#al displays and hard copy displays& 1n

addition the comp#ter also controls the operation of the !'M2 system&

2.2 Pyrolysis,Gas Chromatography4(ass Spectrometry *Py,GC4(S+

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45Applications of Chromatography yphenated *echniues in the Field of ignin Pyrolysis

7hen analyzed the samples are 0rst inserted into a )#artz chamber in apyrolysis #nit (-ig&?" that is then heated resistively in an o%ygen free environment at a pre'settemperat#re for a n#mber of seconds (e&g& >CCH! for 4Cs"& This res#lts in a heat

mediated cleavage of chemicalbonds within the macromolec#lar str#ct#res of interest prod#cing a s#ite of lowmolec#lar weight chemical moieties which is indicative of specific types ofmacromolec#le (e&g& lignin cell#lose hemicell#loses etc&"& This mi%t#re ofcompo#nds is then swept into the analytical col#mn of the ! and !'M2proceeds as normal&

-ig& ?& 2chematic of a

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4 Applications of Gas Chromatographyreports (7# et al& ?CC:B Tan ?CC5"&

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4!Applications of Chromatography yphenated *echniues in the Field of ignin Pyrolysis

Elemental analysis of three types of lignin was implemented in a Gario E3elemental analyzer and an 1!< ind#ctively co#pled plasma emissionspectrometer& Table 4 lists the res#lts of the elemental analysis fromwhich the = content can be calc#lated by difference&

=rganic Elements

1norganic elements ppm

! / @ 2 .l !a @a Mg Mn K Qn !# -eEM.3

.3./3

:&;6 &;? ?&:C&C>>?&?C ;&A; C&C;

&;A 4&?> :C&45 C&A; ' 4?&C 46&6 A&;54C5&4C

' A:4&;5 ??>&;C ?>&4A A&> :C>&?; 5&:;

Table 4& Elemental analysis of the ligninsamples

.2 Analytical pyrolysis-ast pyrolysis of prepared samples was carried o#t in a

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4" Applications of Gas Chromatography

#. 'esults and discussion

#.1 Identi!ication o! pyrolysis products

.ccording to the previo#s introd#ction of !'M2 both )#alitative and

)#antitative analysis of the pyrolysis compo#nds can be achieved with !'M2easily& -or e%ample -ig& A shows T1! chromatogram of ,amboo ligninpyrolysis at >CC! in which each pea+ shown a compo#nd prod#cedd#ring lignin pyrolysis process& .n eective and eicient way to )#alitativeidentify these pea+s is to compare its e%perimental mass spectr#m againsta library of comp#terized mass spectra (Mistri+ ?CC6"&

-ig& A& Total ion chromatograms of ,amboo EM.3 pyrolyzed at>CC!

1n o#r e%periment analysis identification of the pyrolysis compo#nds wasachieved by comparison of their mass fragment with

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4#Applications of Chromatography yphenated *echniues in the Field of ignin Pyrolysis

-ig& 6& 2ome e%amples of mass spectra identified bysearching libraries

#.2 E!!ect o! temperature on E(A3 pyrolysis

,ased on the analysis method described earlier )#antitative information ofbamboo EM.3 pyrolysis prod#cts at dierent temperat#res are presented in

Table ?& .s can be seen from Table ? The major compo#ndsderived from p'hydro%yphenylpropanoid g#aiacylpropanoid andsyringylpropanoid of lignin #nits d#ring pyrolytic reactions were mainlyclassified as the heterocycles (?A'dihydrobenzof#ran" phenols and a smallamo#nt of acetic acid& The yield of phenolic compo#nds increased with anincrease of pyrolysis temperat#re and the highest fraction of phenols was>&6AJ at >CCo!&

.mong these pyrolysis prod#cts the small molec#le compo#nds of vanillin andacetic acid generated as a res#lt of the bond crac+ing of interlin+age !O! oflignin phenylpropane and the brea+age of !O! can ind#ce the prod#ction ofcarbo%ylic acid and carbon dio%ide (Fang et al& ?C4C"& ,ond brea+age of theside chains of lignin str#ct#ral #nits can lead to generate degradationprod#cts with the new hydro%yl and carbonyl gro#ps& Th#s with the contents of

the hydro%yl and carbonyl gro#ps increasing the side chains of aromaticcompo#nds connected to 'carbonyl 'carbo%yl or ester gro#ps appeared(3o# et al&?C4Ca"&

1n all the identi0ed prod#cts ? A'dihydrobenzof#ran (D)%F" acco#nted forthe largest )#antity in addition other compo#nds s#ch as ethenylg#aiacol ?>'di'tert'b#tyl'p'cresol (D$%C" A 'dimetho%yacetophenone (D&AP"metho%ye#genol etc& also acco#nt for considerable amo#nt& 2ome of theseselected compo#nds with higher yields d#ring lignin pyrolysis and theirchemical str#ct#res are shown in -ig& and their yield distrib#tions varying

with pyrolysis temperat#re are presented in -ig& >& The yields of obtainedcompo#nds possessing the syringyl #nit str#ct#re (metho%ye#genolsyringol and syringaldehyde" and ? A'dihydrobenzof#ran (D)%F" are shown in-ig& >(a" and the yield of compo#nds possessing g#aiacyl #nit str#ct#re(ethenylg#aiacol vanillin E'isoe#genol and sinapylaldehyde" are shown in -ig&>(b"&

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A?Co! 6CCo! >CCo! :CCo!

pO/ydro%yphenols 4 ?&55

o'!resol ' ' ' 4&>:

p'!resol ' ' 4&C4 A&:

?>'Di'tert'b#tyl'p'cresol >&54 &:5 ?&4C 4&>;

?6'%ylenol ' ' ' C&::

p'Ethylphenol ' ' C&;6 4&5

?'.llylphenol ' ' ' 4&:6

#aiacols #aiacol ' ' A&;: 4&C:

p'Methylg#aiacol ' ' 4&6 4&;?

Ethenylg#aiacol :&4: 5&?? ;&?A A&4>Ganillin ' ?&;> ?&>6 ?&4

E'isoe#genol ' 4&55 ?&>> ?&CC

2inapylaldehyde ' 4&C 4&5> ?&C4

!oniferylalcohol ' &A6 5&65 '

2yringols 2yringol ' A&; 5&>5 6&A

Methylsyringol ' ' ?&5: A&C4

2yringaldehyde ' ?&A> ?&6? 4&6

Metho%ye#genol 6&> &>; &C> ?&A5.cetosyringone ' ' ' 4&?A

/eterocycles ?A'Dihydrobenzof#ran >>&?> >&>? A>&C 45&4

=thers .cetic acid

A;'Dimethylnonane

'

'

'

'

'

'

C&5;

'A'Dimetho%yacetophenone(D&AP"

6&C5 &4C >&>A ?&?C

m' &;? ;&:5.llylphthalate C&:5 C&5; 4&A; ?&>5

Tetracosane ' ' ' A&>

?'A

Dotriacontane ' ' ' 6&:5

5% Applications of Gas Chromatography

!ompo#nd class

!ompo#nds

Field .rea percent (J" a

a based on the integrated areasB b not detected&

Table ?&

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5ield.

6

5ield.

6

5ield.

6

-ig& & & that almost all of the compo#nds derived from EM.3pyrolysis appeared at 6CCo! e%cept for D)%F metho%ye#genol andethenylg#aiacol emerged earlier at abo#t ACCo!& The formation fraction ofmetho%ye#genol syringaldehyde ethenylg#aiacol and vanillin reached ama%im#m at 6CCo! then the yields of these compo#nds decreased with theincrement of temperat#re which may be beca#se the secondarydecomposition too+ place at high temperat#res& The highest yield of ? A'dihydrobenzof#ran (D)%F" was>>&?>J at A?Co! as pyrolysis temperat#re increased to :CCo! the yield of D/,-decreased rapidly to 45&4J& This con0rms that in lignin pyrolysis process thema%im#m formation of D)%F occ#rred at aro#nd ACCo! (3o# et al&?C4Cb"& The yield of E'isoe#genol and sinapylaldehyde increased slowlybeca#se their chemical str#ct#res possessed the do#ble bonds of side chainand the benzene rings formed conj#gated system th#s became more stableeven at high temperat#re&

#. E!!ect o! catalysts on E(A3 pyrolysisThe eects of catalysts on the yield of prod#cts from EM.3 pyrolysis were st#diedin detail& The )#antitative analysis of pyrolysis prod#ct based on theintegrated areas is shown in Table A and the yield distrib#tions of val#ableprod#ct are present in -ig& ;&

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Field .rea percent(J"

X% 4&?4 4&:A4:&A4,enzenes ,enzene ' 4&4> 4&A 4&5 4&? 4&A5 4&:?

Tol#ene ' 4&:A 4&6C ?&>? ?&4A ?&?6 ?&C?m'ylene ' C&;? C&;6 4&? C&:A 4&?; C&562tyrene ' C&5 ' ' C&:4 ' '&4; &?5 &>6 &;5

pO/ydro%yphenols o'!resol 4&>: 4&5 ?&C6 A&?C 4&:A ?&?;4&:5 p' !resol A&: A&?C A&5>>&CA 6&A4 &?> 6&> o'.llylphenol

'

C&5C ?&C 4&44 4&? ?&?; 4&A m'ylenol C&:: 4&4C 4&;4 ?&C 4&>C ?&C;

?&46 p'Ethylphenol 4&5 ?&AA&4 6&;> ?&4; ?&;: ?&:5

,#tylatedhydro%ytol#ene

' 4&C6 4&>A 4&66 4&CC 4&C6 4&C5

#aiacols o'#aiacol 4&C: C&: 4&: 4&;> 4&;; 4&?; 4&?5Metho%yl phenol 4&;? A&A4 &;C >&A; 4&4 C&:4 4&A?'Dihydro%ytol#ene ' ?&>C A&?C 6&>> 4&;6 ?&5; 4&5:p'Ginylg#aiacol ' A&:6 6&?C 6&C6 &4 ?&A5 6&:6Ganillin ?&4 C&:> 4&?C 4&4C 4&6 4&55 4&5

E9:;'isoe#genol ?&CC ?&?A ?& A&44 ?&A; ?&?? 4&5;'/ydro%yisoe#genol ' C&: C&5C C&5? C&>> 4&CC 4&?A.cetog#aiacone ' ' ' ' C&>? C&> C&:A-er#lic acid ' :&6C 6&5A A&> C&>C C&6: C&A;

2yringols 2yringol 6&A 4&A? 4&55 4&4: &? 6&56 6&A6A6'Dimetho%yphenol

' 4&C; 4&;C 4&:> ' ' '

Metho%ye#genol ?&A5 4&A 4&C? C&:4 ?&?5 4&>> 4&>A2yringaldehyde 4&6 5&A? ?&66 4&? C&A> C&66 4&4.cetosyringone 4&?A ' ' ' C&:? C&:> 4&6?#aiacylacetone ' 4&> ' ' ' ' '

!atechols 6'Ethylcatechol ' ' 4&C; 4&C6 4&44 C&:6 C&;6A'Mmethyl'4?'benzenediol

' ?&?: A&6 A&;; ' ' '

?A'/eterocycles

Dihydrobezof#ran(D)%F"

45&4 4>&AC 4&6A 4A&C: ?4&6?A&;: ?6&45

=thers .cetic acid C&5; 4&:5 A&C &:6 A&; A&>: 6&C4-#rf#ral ' C&5; 4&C; 4&A5 4&C: 4&CA C&564?6'

Trimetho%ybenzene' 4&C; ?&C4 4&A? ?&:; ?&A6 ?&?>

A'Dimetho%yacetophen one (D&AP"

?&?C A& ?&? 4&5> A&4? ?&?? ?&4

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J 4CJ ?CJ J 4CJ ?CJ

p'pP'1sopropylidenebisph ;&:5 ?&54 4&A: 4&CC ' ' 'enol (IP%P"Dib#tyl phthalate 4&>A C&5C 4&64 C&;; ' ' '6'/ydro%y'A'dimetho%ybenzohy ' A&>? 4&46 C&;: ' ' 'azide

!ompo#nd class

!ompo#nds

Field .rea percent(J"

EM EM.3 X%@a!lEM.3

.3

X%

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5ield

.6

2" 5

DHBF Ethylphenol24 4

2% 3

$2

$2

49%%6 56 $%6 2%6

$

295%6 56 $%6 2%6

395

39%

DMAP Methoxyeugenol

29%

$95

295

29%

%6 56 $%6 2%6

(b"

$9%

%95%6 56 $%6 2%6

5

4

3

2

$

395

Syringol

%6 56 $%6 2%6

295

29%

$95

$9%

%95

$%

Vanillin

%6 56 $%6 2%6

39%

295

29%

$95

E(Z!i"oeugenol" Syringaldehyde

4

2

%%6 56 $%6 2%6

$%#PBP

"

4

2

%%6 56 $%6 2%6

%6 56 $%6 2%6

$%

" Ferulic acid

4

2

%%6 56 $%6 2%6

0osage ofcatalyst

(c"

-ig& ;&

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5ield

46

.dditive @a'salt and perm#tite promoted the formation of small molec#les& Theamo#nt of acetic acid phenol f#rf#ral and benzene varying with dosage ofcatalyst is shown in -ig&;(a"& 1t revealed that yields of acetic acid phenol f#rf#ral and benzene

increased with an increase of the dosage of two catalysts and the two catalystsin EM.3 pyrolysis promoted the generation of benzene and f#rf#ral& 7henthe dosage of perm#tite was J the formation rate of acetic acid phenoland f#rf#ral were the most distinct as the amo#nt of perm#tite f#rtherincreased the increase in yield of them was not obvio#s& /owever as theamo#nt of @a!l increased the yield enhanced considerably& 1n short theaddition of two catalysts promoted the cleavage of lignin and the generation ofsmall molec#le compo#nds&

1t can be obtained from -ig& ;(b" that with the additive catalyst increasing fromJ to ?CJ perm#tite has a signi0cant role in promoting the formation of D)%Ffrom 45&4J to ?6&45J however @a!l catalyst was eective to red#ce the

prod#ction of D)%F from 45&4J to4A&C:J& =n the yields of ethylphenol D&AP and metho%ye#genol d#ring EM.3catalytic pyrolysis the catalysts of perm#tite and @a!l had the sameimpact& !ompared with perm#tite @a!l catalyst had more prono#nced eect toimprove or s#ppress the generation of ethylphenol D&AP and metho%ye#genol&

-ig& ;(c" shows that when @a!l catalyst was J prod#ct of syringaldehyde andfer#lic acid reached their ma%im#m yield while with f#rther increase in theamo#nt of catalyst the yield decreased& This was similar to that of D&AP shownin -ig& ;(b"&

Two +inds of phenolsP generation trends (i&e& g#aiacols and syringols" aected by

variations of temperat#re and catalysts are shown in -ig& :& ,oth g#aiacols andsyringols reached their ma%im#m yields at >CCo!& The catalytic eects of@a!l and perm#tite for improving g#aiacols were the most prominent atdosage of J however the catalytic eect of perm#tite for syringols wasnot obvio#s&

Guaiacols3% Syringol

Guaiacols

3% Syringols

8aCl

999999999Permutite

2% 2%

$% $%

% %3%% 4%% 5%% %% !%% "%%

&emperature4 oC

% 56 $%6 2%6

Dosage o!catalyst

-ig& :& The total amo#nt of g#aiacols and syringols with pyrolysisconditions

To s#m #p the impact of dierent catalysts on the selectivity of pyrolysisprod#cts is dierent& !ompared with perm#tite the effect of catalyst @a!l wasconsidere