Water – Ionic Liquid Interaction Studies New Definition of · Ionic Liquids Under Study ......

BL 06/2007

Water – Ionic Liquid Interaction Studiesby MIR and THz

New Definition ofProcess Gas

Chromatography

Probing intermolecular interactions in water/ionic

liquid mixtures by THz spectroscopy

Introduction

Ionic Liquids

MIR Studies

2DCoS

MCR -ALS

FIR Studies

MCR-ALS

Conclusions

Bernhard Lendl

Institute of Chemical Technologies and Analytics, TU Vienna, Austria

BL 06/2007


Introduction / Motivation

Ionic Liquids – molten salts at room temperature

Flow Injection System – to generate spectra

Data Analysis Techniques

- MCR

- 2DCoS

Results

MIR Studies

THz (FIR) Studies

Outline

Introduction

Ionic Liquids

MIR Studies

2DCoS

MCR -ALS

FIR Studies

MCR-ALS

Conclusions

BL 06/2007


Ionic Liquids

Properties of Ionic Liquids

Salts containing organic cations and inorg. or organic anionsMolten salts at or slightly above room temperature (max.

100°C)Good solvation powerGood thermal stability (ca. 300ºC)Negligible volatilityGood electrical conductivity

Typical Building Blocks

Introduction

Ionic Liquids

MIR Studies

2DCoS

MCR -ALS

FIR Studies

MCR-ALS

Conclusions

BL 06/2007


Ionic Liquids Under Study

Selected Ionic Liquids

tetrafluoroborate hexafluorophosphate

1-ethyl-3-methylimidazolium

“emim+”

1-butyl-3-methylimidazolium

“bmim+”

Liquid at room temperature



Solid at room temperature

Introduction

Ionic Liquids

MIR Studies

2DCoS

MCR -ALS

FIR Studies

MCR-ALS

Conclusions

BL 06/2007


MIR Spectra of Ionic Liquids Under Study

ATR (1 bounce) spectra of dry Ionic Liquids

3500 3000 2500 2000 1500 1000 500

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8Ab

sorb

ance

Wavenumber, 1/cm

emimBF4 bmimBF4 bmimPF6

3400 3200 3000 2800 26000.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

Abso

rban

ce

Wavenumber, 1/cm

Introduction

Ionic Liquids

MIR Studies

2DCoS

MCR -ALS

FIR Studies

MCR-ALS

Conclusions

BL 06/2007


FIR Spectra of Ionic Liquids Under Study

600 500 400 300 200 100

0,0

0,5

1,0

1,5

2,0 emimBF4 bmimBF4 bmimPF4

Abso

rban

ce u

nits

Wavenumber (cm-1)

25 µm transmission cell (PE windows)

Introduction

Ionic Liquids

MIR Studies

2DCoS

MCR -ALS

FIR Studies

MCR-ALS

Conclusions

BL 06/2007


Motivation

Traces of co-solvents change properties of ionic liquids

Get fundamental understanding on formation of small water clusters

Fun

Results

MIR Studies

THz (FIR) Studies

Water - Ionic Liquid Interaction

Introduction

Ionic Liquids

MIR Studies

2DCoS

MCR -ALS

FIR Studies

MCR-ALS

Conclusions

BL 06/2007

Water – Ionic Liquid Interaction Studiesby MIR and THz Type of anion influence position of OH-stretch vibrations


0,000,02

0,040,060,08

0,100,120,140,16

0,180,20

325033503450355036503750

Wavenumber 1/cm

Abs

orba

nce

emimBF4

bmimBF4

bmimPF6

Introduction

Ionic Liquids

MIR Studies

2DCoS

MCR -ALS

FIR Studies

MCR-ALS

Conclusions

BL 06/2007

Water – Ionic Liquid Interaction Studiesby MIR and THz Change in ν-OH-stretch region as function of water

concentration


0,00

0,20

0,40

0,60

0,80

1,00

1,20

325033503450355036503750

Wavenumber 1/cm

Arb

itrar

y U

nits

high concentration

low concentration

Introduction

Ionic Liquids

MIR Studies

2DCoS

MCR -ALS

FIR Studies

MCR-ALS

Conclusions

BL 06/2007



Pure IL

in out

Sample

Holding coil500μl

Syringe pump1000μl

Waste

ThermostatedFlow cell

Bruker IFS 88Sagitarius V3

Introduction

Ionic Liquids

MIR Studies

2DCoS

MCR -ALS

FIR Studies

MCR-ALS

Conclusions

BL 06/2007


H2O in emim+[BF4]- and bmim+[BF4]-

3300340035003600370038000

0.2

0.4

0.6

0.8

1

Wavenumber / cm-1

Abs

orba

nce

3640

3564

3450

3640

Set of spectra covering 0-5% m/m of H2O in [BF4]- based ionic liquids

Introduction

Ionic Liquids

MIR Studies

2DCoS

MCR -ALS

FIR Studies

MCR-ALS

Conclusions

BL 06/2007


2DCoS - Concept

( ) ( )2121 ,, νννν Ψ+Θ i

( ) ( )ϖϖπ 2

01

1 YiYT

+= ∫∞

Time resolved spectra Time/pressure/Temperature,..

Correlation analysis

Spectral Variable

I. Noda Lecture 2DCoS-3, 2005

Looking for correlation in the experimental output D

Introduction

Ionic Liquids

MIR Studies

2DCoS

MCR -ALS

FIR Studies

MCR-ALS

Conclusions

BL 06/2007


2DCoS - Output

I. Noda Lecture 2DCoS-3, 2005

Correlation Maps

Spectral variable, ν1

Spe

ctra

lvar

iabl

e, ν

2

Spectral variable, ν1

Spe

ctra

lvar

iabl

e, ν

2

Synchronous map Asynchronous mapIntroduction

Ionic Liquids

MIR Studies

2DCoS

MCR -ALS

FIR Studies

MCR-ALS

Conclusions

BL 06/2007


Asynchronous Correlation Map : H2O in emim+[BF4]- and bmim+[BF4]-

Peaks in asynchronous correlation map:3640 – 3610 cm-1; 3640 - 3450 cm-1; 3610 - 3560 cm-1 and 3560 - 3450 cm-1

No correlation between 3610 - 3450 cm-1 and 3640 - 3560 cm-1

=> presence of 2 different species 1st Specie: Bands at 3640 - 3560 cm-1

2nd Species: Bands at 3610 and 3450 cm-1W

aven

umbe

r / c

m-1

Wavenumber / cm-1340036003800

3300

3400

3500

3600

3700

3800

Wav

enum

ber /

cm

-1

Wavenumber / cm-1340036003800

3300

3400

3500

3600

3700

3800

3640

3610 3450 3560

36103560

3450

Introduction

Ionic Liquids

MIR Studies

2DCoS

MCR -ALS

FIR Studies

MCR-ALS

Conclusions

BL 06/2007


Multivariate Curve Resolution (MCR-ALS)

Concept: Modeling of experimental data matrix D

D = CST + E

D(r × c) is the original data matrix C(r × n) and ST(n×c) contain pure response profiles related to the data variation in the row (r) and column (c) direction of D(r × c)E(r × c) is the error matrix

• Multi-component systems can be often be described witha simple model consisting of the composition-weightedsum of signals of their pure components

• Only condition: linear structure of data set

Introduction

Ionic Liquids

MIR Studies

2DCoS

MCR -ALS

FIR Studies

MCR-ALS

Conclusions

BL 06/2007


Multivariate Curve Resolution:

ci...concentration profiles with time si...spectra of pure substances

= ++c1

s1T

c3

s3T

c2

s2T

=C

ST

exp. dataD

ν

t =

ci...concentration profiles with time si...spectra of pure substances

= ++c1

s1T

c1

s1T

c3

s3T

c2

s2T

=C

ST

exp. dataD

exp. dataD

exp. dataD

ν

t = + E

+ E

Graphical Representation

Introduction

Ionic Liquids

MIR Studies

2DCoS

MCR -ALS

FIR Studies

MCR-ALS

Conclusions

BL 06/2007


2DCoS vs. MCR-ALS

Two complementary approaches which help to gain understanding of dynamic processes

2DCoS: Looking for correlation in the data set

Output: synchronous and asynchronous correlation mapsrequires some art to read the maps

MCR-ALS: Modeling of the data set

Output: spectra and concentration profiles of compounds requires definition of compounds rather objective criteria whether modeling was successful

Introduction

Ionic Liquids

MIR Studies

2DCoS

MCR -ALS

FIR Studies

MCR-ALS

Conclusions

BL 06/2007


0 100 200 3000

1

2

3

4

5

Time / sec

Arb

itrar

y U

nits

0 100 200 3000

1

2

3

4

5

6

Time / sec

Arb

itrar

y U

nits

3 3 0 03 4 0 03 5 0 03 6 0 03 7 0 03 8 0 00

0 .0 3

0 .0 6

0 .0 9

0 .1 2

0 .1 5

W a v e numbe r / c m-1A

rbitr

ary

Uni

ts

bmim+[BF4]- emim+[BF4]-

[BF4]-

Spectra of encountered compounds

Concentration of encountered compounds

Introduction

Ionic Liquids

MIR Studies

2DCoS

MCR -ALS

FIR Studies

MCR-ALS

Conclusions

Results of MCR-ALS

BL 06/2007


Influence of the Cation

0 100 200 3000

0.5

1

1.5

2

2.5

3

3.5

Time / sec

Arb

itrar

y U

nits

0 100 200 3000

1

2

3

4

5

Time / sec

Arb

itrar

y un

itsbmim+ emim+

Theory of FIA explains the form of the FIA peaks as a result ofconvection (dominating) and diffusionUpon increasing viscosity, radial diffusion is less pronounced => higher dispersion

radial diffusion convection

Cation determines the dispersion profile of the FIA peaks

0 100 200 3000

0.5

1

1.5

2

2.5

Time / sec

Arb

itrar

y U

nits bmim+

Introduction

Ionic Liquids

MIR Studies

2DCoS

MCR -ALS

FIR Studies

MCR-ALS

Conclusions

BL 06/2007


Only type present in PF6- based I.F.

as well as first water species in BF4-

containing I.L. is monomeric water:

First Water Species

3300340035003600370038000

0.03

0.06

0.09

0.12

0.15

Pastor et al. J Phys Chem. B 110 (2006) 10896-10902

Water species as resolved by MCR - ALS

Introduction

Ionic Liquids

MIR Studies

2DCoS

MCR -ALS

FIR Studies

MCR-ALS

Conclusions

BL 06/2007


Second Water Spezie

• Bands at 3610 cm-1 and 3450 cm-1

• Literatur: (Koeddermann et al.Absorptionen in CCl4):Water dimer at 3553 cm-1

Cyclic water trimer at 3409 cm-1330034003500360037003800

0

0.03

0.06

0.09

0.12

0.15

Our data suggest the following structure:

Pastor et al. J Phys Chem. B 110 (2006) 10896

Introduction

Ionic Liquids

MIR Studies

2DCoS

MCR -ALS

FIR Studies

MCR-ALS

Conclusions

BL 06/2007


Water - Ionic Liquid Interaction in the FIR

Pure IL

in out

Sample

Holding coil500μl

Syringe pump1000μl

Waste


Bruker IFS 66vSagitarius V3

Pure IL

in out

Sample

Holding coil500μl

Syringe pump1000μl

Waste


Bruker IFS 66vSagitarius V3

Introduction

Ionic Liquids

MIR Studies

2DCoS

MCR -ALS

FIR Studies

MCR-ALS

Conclusions

BL 06/2007


FIR (THz) Spectra Recorded at Bessy

500 400 300 200 1000,0

0,2

0,4

0,6 emimBF4 bmimBF4 emimPF6

Abso

rban

ce u

nits

Wavenumber (cm-1)

500 400 300 200 1000,0

1,0

2,0

3,0

Wavenumber (cm-1)

Inte

nsity

uni

ts

H HO

BF4-Single Beam Spectrum H H

O

FIR Spectra of 2% (w/w) of H2O in Ionic Liquids

Dominguez et al. J. Phys. Chem. B 11 (2007) 4446-4452

Introduction

Ionic Liquids

MIR Studies

2DCoS

MCR -ALS

FIR Studies

MCR-ALS

Conclusions

BL 06/2007


Matrix Augmentation in MCR Analysis

Simultaneous Analysis of Several Experiments

blank

emimBF45% H2O

Exp. withEnzymebmimBF45% H2O

Introduction

Ionic Liquids

MIR Studies

2DCoS

MCR -ALS

FIR Studies

MCR-ALS

Conclusions

BL 06/2007


Results of Matrix Augmentation

0 100 200 300 400 5000,0

1,0

2,0

3,0

4,0C

once

ntra

tion

(AU

)

Time (s)0 200 400 600 800 1000

0,0

1,0

2,0

3,0

4,0

Time (s)

350 300 250 200 150 100 50

0,00

0,05

0,10

0,15

0,20

Wavenumber (cm-1)

Abs

orba

nce

(AU

)

0 200 400 600 800 10000,0

1,0

2,0

3,0

4,0

Time (s)

Blank bmimBF4 emimBF4

148 cm-1

202 cm-1

H HO

BF 4-

O H O

Dominguez et al. J. Phys. Chem. B 11 (2007) 4446-4452

Introduction

Ionic Liquids

MIR Studies

2DCoS

MCR -ALS

FIR Studies

MCR-ALS

Conclusions

BL 06/2007


Conclusions

Spectra of Ionic Liquids from the MIR-FIRspectral region

Flow Injection Analysis very suitable for generate of binary mixtures of ionic liquids and water

In emimBF4 water dimers can be found and a cyclicstructure can be proposed

In bmimPF6 only water monomers could be detected

Successful use of 2DCoS and MCR-ALS ascomplementary techniques to resolve overlappingfeatures and components

Introduction

Ionic Liquids

MIR Studies

2DCoS

MCR -ALS

FIR Studies

MCR-ALS

Conclusions

BL 06/2007


Acknowledgements

Maria JoseAyora Canada

Ana Dominguez Vidal Mercedes Lopez Pastor

Nina Kaun - Ulli Schade

Introduction

Ionic Liquids

MIR Studies

2DCoS

MCR -ALS

FIR Studies

MCR-ALS

Conclusions

Water – Ionic Liquid Interaction Studies New Definition of · Ionic Liquids Under Study ......

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Transcript of Water – Ionic Liquid Interaction Studies New Definition of · Ionic Liquids Under Study ......