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1 F32 Fatty acids
Contents
1. Occurrence of the fatty acids 3
2. Chemical structure 4
3. Properties of the fatty acids 7
4. Reference numbers of the fatty acids 8
5. Extraction of the fatty acids 9
6. Technical variations and specialties 13
7. Application areas 17
8. Market data 18
9. Trade Names at Cognis 20
10. Keywords21
F32 Fatty acids 2
3 F32 Fatty acids
Chapter 1Occurrence of the fatty acids
Fatty acids are a component of the natural oils and fats. They are esterified with glycerine and form triglycerides.
glycerine part fatty acid part
c o c
RH c o c
H
o
R
RH c o co
o
2
2
Fig.. 1 Structure of the fatty acids
The percentage of fatty acids in the oils and fats is different from resource to resource. Coconuts or palm kernels deliver mainly C12 / C14, tallow or palm oil mainly C16 / C18, for example.The most important fatty acids in oleochemicals are found in the following natural oils and fats:
coconut
palm kernel
tallow
palm oil
rape rich
poor
sunflower
soya
8
C-c
hain
dis
trib
uti
on
an
d q
uan
tity
C8 C10 C12 C14 C16 C18 C20 C22
7 48 17 9 10
54 50 15 7 18
4 30 65
2 42 56
2 38 7 50
4 90 2 3
6 93 1
8 91
Fig. 2 C-chain distribution in natural oils and fats
F32 Fatty acids
Chapter 2Chemical structure
Fatty acids belong to the chemical group of the carboxylic acids. The carboxylic acids are characterized by a carboxylic (or carboxo) group (COOH) that is attached to a hydrocarbon chain (abbreviated R).The carboxylic group is responsible for the acidic effect of these substances, because it is able to set free a hydrogen ion (H+) when solved in water.
Fig. 3 Structure of the carboxylic acids
The chemical name "carboxylic acid" is derived from the basic hydrocarbon to which the addition "acid" is connected to.The following table shows a carboxylic acid that is very important in oleochemicals:
lauric acid, C12
H C
H
H
C
H
H
C
H
H
O HC
O
C
H
H
C
H
H
C
H
H
C
H
H
C
H
H
C
H
H
C
H
H
C
H
H
acid groupcarbon chain
Fig. 4 Structure of the lauric acid
From the number of 4 carbon atoms in the hydrocarbon chain on, the carboxylic acids are called fatty acids.Fatty acids from natural oils or fats are always even-chained and have got an even number of carbon atoms. This is due to the elongation process that takes place in plants.
A difference is made between saturated and unsaturated fatty acids.Saturated fatty acids contain only single bonds (C-C) in their hydrocarbon chain.
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5 F32 Fatty acids
Unsaturated fatty acids contain at least one double bond in their hydrocarbon chain (C=C). If more than one double bond exists, they are called multiple (double, triple etc.) unsaturated fatty acids.
Here are examples of the C18 fatty acids (fatty acids with 18 carbon atoms):
C
H
H
C
H
H
C
H
H
O HC
O
C
H
H
C
H
H
C
H
H
C
H
H
C
H
H
C
H
H
C
H
H
C
H
H
C
H
H
C
H
H
C
H
H
C
H
H
C
H
H
C
H
H
H
stearic acid (octadecanoic acid) C H COOH17 35
C 18 fatty acid, saturated
C 18 fatty acid, single unsaturated
oleic acid (octadecenoic acid)
C
H
H
C
H
H
C
H
H
O HC
O
C
H
H
C
H
H
C
H
H
C
H
H
C
H
H
C
H
H
C
H
H
C
H
H
C
H
C
H
C
H
H
C
H
H
C
H
H
C
H
H
H
C H COOH17 33
C
H
H
C
H
H
C
H
H
O HC
O
C
H
H
C
H
H
C
H
H
C
H
H
C
H
C
H
C
H
H
C
H
C
H
H
C
H
C
H
H
C
H
H
C
H
H
C
H
H
H
linoleic acid (octadecadienoic acid) C H COOH17 31
C 18 fatty acid, double unsaturated
C 18 fatty acid, triple unsaturated
linolenic acid (octadecatrienoic acid)
C
H
H
C
H
H
C
H
H
O HC
O
C
H
H
C
H
H
C
H
C
H
C
H
C
H
C
H
H
C
H
H
C
H
C
H
C
H
H
C
H
H
C
H
H
C
H
H
H
C H COOH17 29
Fig. 5 C 18-fatty acids
Apart from the chemical names there exist so-called trivial names of the fatty acids as well. These names were introduced most often with the discovery of the fatty acids.The dodecanoic acid for example was first found in the fruits of the laurel tree (Latin: Laurus nobilis) and was thus called lauric acid.In the oleochemical terminology still the trivial names are most often used.
The most important fatty acids are the following:
Saturated fatty acids
C 6 Hexanoic acid Caproic acid
C 8 Octanoic acid Caprylic acid
C 10 Decanoic acid Caprinic acid
C 12 Dodecanoic acid Lauric acid
C 14 Tetradecanoic acid Myristic acid
C 16 Hexadecanoic acid Palmitic acid
F32 Fatty acids
C 18 Octadecanoic acid Stearic acid
C 20 Eicosanoic acid Arachidic acidC 22 Docosanoic acid Behenic acid
C 24 Tetracosanoic acid Lignoceroic acid
Unsaturated fatty acids (number of double bonds /.)
C 18 / 1 Octadecenic acid Oleic acid
C 18 / 2 Octadecadienoic acid Linoleic acid
C 18 / 3 Octadecatrienoic acid Linolenic acid
C 20 / 1 Eicosenoic acid Gadoniloic acid
C 20 / 4 Eicosatetraenoic acid Arachidic acid
C 22 / 1 Docosenoic acid Erucic acid
C 22 / 5 Docosapentanoic acid Clupanodonic acid
The ricinoleic acid is in a special position. It is a single unsaturated fatty acid that at-taches a hydroxyl group (OH) to a C-atom.Castor oil contains 87 % of the ricinoleic acid that has the chemical name 12-Oxy-Octadecenic acid.
C
O
H
C
H
H
C
H
H
O HC
O
C
H
H
C
H
H
C
H
H
C
H
H
C
H
H
C
H
H
C
H
H
C
H
H
C
H
C
H
C
H
H
C
H
H
C
H
H
C
H
H
H
Ricinoleic acid
C H OH COOH17 32
H
Fig. 6 Structure of the ricinoleic acid
To this additional hydroxyl group one can add for example ethylene oxide to get an emulsifier such as Eumulgin RO40.
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7 F32 Fatty acids
Chapter 3Properties of the fatty acids
Pure fatty acids are colorless substances. Their melting point rises with the increas-ing chain length, the unsaturated fatty acids have got a lower melting point (mp) than the saturated ones. In the oleo chemistry the solidification point (called Titer with fatty acids) is indicated which is usually a little lower than the melting point.
fatty acids length Titer/°C mp/°C
capronic acid C6 -3,4 4caprylic acid C8 16 17capric acid C10 31,3 31lauric acid C12 43,5 43myristic acid C14 54,4 54palmitic acid C16 62,9 63stearic acid C18 69,6 71
oleic acid C18/1 13,4 16erucic acid C22/1 34,7 34linoleic acid C18/2 -5,0 -5linolenic acid C18/3 -11 -11
Fig. 7 Solidification points of the fatty acids
Even the boiling points increase with the rising chain length. By the raising of number of double bonds the boiling point decreases again. Not every acid can be measured at usual atmospherically pressure (1013 mbar). For some boiling points (Bp) one has to lower the pressure and get degrees of centigrade in vacuum. Therefore the fig-ures /mbar are added. Otherwise the acids are cracked before they can reach the boiling points.
fatty acid length Mp/°C Bp/°C/mbar
capronic acid C6 4 101/1013caprylic acid C8 17 239/1013Capric acid C10 31 270/1013lauric acid C12 43 225/133myristic acid C14 54 250/133palmitic acid C16 63 272/133stearic acid C18 71 291/133oleic acid C18/1 16 229/20erucic acid C22/1 34 225/13linoleic acid C18/2 -5 230/21linolenic acid C18/3 -11 232/23
Fig. 8 Boiling points of the fatty acids
The viscosity of the fatty acids rises as well with the increasing chain length and falls with the increasing number of double bonds.Fatty acids are soluble in organic solvents (e.g. alcohol, gasoline etc.). The solubility gets worse with the increasing chain length, but a higher temperature can compen-
F32 Fatty acids
sate this. Water and fatty acids are only hardly soluble at room temperature; the short chain fatty acids have an advantage over the long chain.
Chapter 4Reference numbers of the fatty acids
The reference numbers of the fatty acids are part of the quality specification. They are measured after the instructions of the ”Deutschen Gesellschaft für Fettchemie” (DGF) (German Society for Oleo chemistry) and they allow a clear characterization of the products.Since no 100 % clean fatty acid from natural oils and fats exists and since many products contain a mixture of fatty acids depending on the raw material (e.g. coconut oil fatty acid) it is important to indicate the distribution of the C-chains in percent.This C-chain spectrum (see Fig. 2) is measured after DGF C-VI 10 with the help of the gas chromatography or other chromatographically methods (such as HPLC).
entry ofsample
separatortube
recorder
detector
Fig. 9 Schematic drawing of a gas chromatograph
Apart from the C-chain distribution a couple of other chemical and physical parameters are measured that serve the purity control of technical fatty acids.The iodine value indicates the amount of unsaturated components. The higher the iodine value, the more double bonds. Most often the measuring of the bromide value is carried out after Kaufmann (DGF C-V 11 d). The acid value (DGF C-V 2) indicates the amount of free fatty acids, measured in mg KOH, that are necessary to neutral-ize 1g of the test substance. The saponification value (DGF C-V 3) is a measure for the free and bound fatty acids in the test substance. It indicates the amount of mg KOH that are necessary to saponify 1 g of the substance.
SAPONIFICATION VALUE: -> free fatty acids -> fatty acids bound to glycerine
SVDefinition: SV indicates how many mg KOH are neces- sary for the saponification of 1g fat / oil.
ACID VALUE: -> free fatty acids
AV Definition: AV indicates how many mg KOH are neces- sary to neutralize the free fatty acids in 1g of fat / oil.
ESTER VALUE: -> inner esters
EV Definition: EN indicates how many mg KOH are neces- sary for the saponification of the esters in
1g of fat / oil.
SV - AV = EV
Fig. 10 Overview of titration numbers
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9 F32 Fatty acids
The content of unsaponifiable material (e.g. sterines, vitamins, hydrocarbons etc.) is another indicator for the quality and is about 0,5 to 2 % with technical fatty acids.As a physical parameter the solidification point (also called Titer) is important. It indi-cates the temperature in °C at which a liquid fatty acid reaches its maximum solidifi -cation (DGF C-IV 3 c).With low melting fatty acids that do not have a solidification point that is easy to indi-cate, the cloud point is indicated instead. That means the temperature in °C, at which a cooled and solidifying fatty acid becomes perceptibly cloudy. (DGF D-III 3).In order to check the quality of the technical fatty acids, also the color measuring is used, either by the comparison with color glasses after Lovibond 5 1/4” (DGF CIV 4 b) or after Gardner (DGF C-IV 4 c) or by the comparison with color solutions after Hazen (also called APHA dye value) (DIN 53409). In this way components that cause a change of color can be indicated.
1. TINTOMETRY: Comparison with coloured glasses
LOVIBOND dye valueGARDNER dye value
2. COLOMETRY: Comparison with coloured solutions
Hazen dye valueAPHA dye value
3. PHOTOMETRY: Measuring of the absorption degree
Principle: reflection / absorption in- UV range- visible light- IR range
Fig. 11 Overview of dye values
All these parameters are dealt with in detail in the course K11 ("Physical and chemi-cal data for Oleochemicals") and the accompanying brochure. Here only one general note: The clearer the starting material the higher the quality of our products: Each re-action or subsequent treatment goes hand in hand with a thermo or mechanical strain.
Chapter 5Extraction of the fatty acids
Cognis extracts fatty acids from natural oils and fats.Partly these raw materials have to be pre-cleaned in order to remove carbohydrates, sterines, proteines, phosphatides and other impurities.Especially with the treatment of oils and fats for purposes of nutrition the cleaning (raffination) is carried out thoroughly. In this process also the so-called free fatty acids (not bound to glycerine) are removed. These fatty acids (raffination fatty acids or soap stock fatty acids) get into the technical further treatment.The main part of the fatty acids for the oleo chemistry is extracted by the hydrolytic fat splitting.The chemical base for this process is the dissolving of the ester bond by the addition of water. Glycerine and fatty acids are the result.
F32 Fatty acids
H
C
C
C
H
H O
H O
H O C R1
O
C R2
O
C R3
O
OH H
OH H
OH H
H
C
C
C
H
H O
H O
H HO
H
H
CR1
O
CR2
O
CR3
O
O H
O H
O H
triglyceride + water glycerine + fatty acid
Fig. 12 Hydrolytic fat splitting
In this process water is added continually to the oils and fats at a temperature of up to 260 °C and a pressure up to 60 bars. In the reaction vessels two phases are found during the splitting process: An aqueous phase that consists of water and glyc-erine and a fatty phase that consists of fat and fatty acids. The split fatty acids and the glycerine water are removed continually.
oils/fats
autoclave
water
steam
split fatty acid
let-down vessel
glycerinewater
Fig. 13 Process of the hydrolytic fat splitting
By the addition of alkaline catalysts (ZnO, MgO, CaO) the reaction speed can be risen. Because these alkaline catalysts form soaps during the splitting process that are solved in the produced split fatty acid, it is necessary to acidify thereafter in order to replace the soaps.At the pressure less splitting at a temperature of 100 °C acid catalysts (aromatic sul-fonic acids in combination with sulfuric acid) are applied to rise the speed of the re-action.Another method to extract fatty acids from natural oils and fats is the saponification of these raw materials. Potash lye (KOH) is added to the oils and fats and the result is glycerine and potash salts of the fatty acids (so-called potassium soap).
H
C
C
C
H
H O
H O
H O C R1
O
C R2
O
C R3
O
H
C
C
C
H
H
H O
H HO
H
H
CR1
O
CR2
O
CR3
O
O K
O K
O K
HK O
HK O
HK O O
triglyceride + KOH glycerine + potassium soap
10
11 F32 Fatty acids
Fig. 14 Saponification of the oils and fats with potash lye
Thereafter hydrochloric acid is acidified: Fatty acids and potassium chloride are the result.
hydrochloricacid
+ potassium soap
potassiumchloride
+ fatty acid
CR
O
O K CR
O
O HH C l K C l
Fig. 15 Extraction of fatty acids from potassium soaps
This method is only applied with castor oil today, because the OH-group of the rici-noleic acid would be destroyed during the splitting process with water (hydrolytic fat splitting).The raw fatty acids produced this way still contain residues and unsplitted fatty acid glycerides (mono- and diglycerides). This is why the split fatty acids are distilled for cleaning purposes. Thus one gets the so-called distillate fatty acid. It is a fatty acid mix that corresponds in its composition to the fatty acid that is esterified in the start -ing raw oil or -fat.
In order to separate the natural fatty acid mixes in the fatty acids (called fractions or cuts) different methods are applied:
a) Fractionated distillation
The fractionated distillation is based on the different boiling points of the fatty acids. The differences are 15 - 30 °C with successive, even-numbered fatty acids, so an extraction of single fatty acid chains is possible up to a purity of 99 %.With a fractionated distillation of a fatty acid mix from coconut oil in the first distilla-tion column a mix of caprylic- and capric acid results and lauric acid in the second column. In a further distillation with higher temperatures one gets the higher-boiling fatty acids, C 14.If it is intended to split up a fatty acid mixture with the same chain length but with dif -ferent degrees of saturation (e.g. from palm oil: A mixture from stearic acid, oleic acid and linoleic acid with myristic- and palmitic acid), the unsaturated components have at first be changed to saturated ones (see chapter 6: Technical variations).The differences in boiling temperature between the fatty acids with the same chain length are too little to get clean fractions without this modification. By the fractionated distillation one gets e.g. from hardened palm oil fatty acid about 2 % of myristic acid (C 14), 42 % palmitic acid (C 16) and 50 % stearic acid (C 18).In order to keep the unsaturated parts, Cognis developed the so-called transwetting method that is explained in the following:
b) Fractionated crystallization
The method of the fractionated crystallization is based on the different melting points of the fatty acids and on the fact that melted fatty acids form crystals when they cool down and slowly get solid again.
F32 Fatty acids
Significantly different are the melting points between the saturated fatty acids (palmitic and stearic acid) and the unsaturated ones (oleic acid) in the tallow fatty acid. The saturated components have a higher melting point and thus crystallize first when the melted substance cools down. In a certain temperature range two phases are found: A liquid one (mainly unsaturated fatty acids) and a solid one in form of crystals (mainly saturated fatty acids).Pressing in former times carried out the separation of these phases: The two-phase-mixture was wrapped in cloth and a pressure was exerted by hydraulic presses. The liquid components could thus run off through the clothes.The parts of the two-phase-mixture can be separated easier than by pressing if a wetting agent solved in water is added to the mix.A wetting agent is a substance that causes an adherence of water (wetting) at the surface of a solid material (e.g. of a crystal). The water together with the wetting agent keeps the liquid fatty acids away from the direct surroundings of the solid fatty acid crystals.This process is called rewetting, because the fatty acid crystals are now wetted by the water and not, as before, by the liquid fatty acids. The result is a mixture of emul-sion (water/liquid fatty acid crystals) and a suspension (water/solid fatty acids) that can easily be separated by centrifugation (fast spinning). Thereafter only the water has to be removed. Cognis developed this rewetting procedure. E.g. fatty alcohol sulfates can be used as wetting agents.
1. Fatty acid crystals (e.g. stearic acid) are finely distributed in liquid fatty acid (e.g. oleic acid)
2. Addition of water + wetting agent (e.g. fatty alcohol sulfate). The stearic acid crystals are no longer wetted by the oleic acid, but by water (suspension). The liquid oleic acid is distributed in the water as small droplets (emulsion).
3. By centrifugation (quick spinning) the two phases are separated.
stearic acid
oleic acid
oleic acid
stearic acidwater
Fig. 16 Transwetting with the fractionated crystallization
Within Cognis Corp. a solvent process is used instead of water with a wetting agent.Synthetic fatty acids
In petrochemicals fatty acids can also be produced by the oxidation of paraffines (alkanes).The fatty acids extracted this way may also have branched chains and can be of an uneven number.The synthetic fatty acids form only a small part of the production of even-chained, even-numbered fatty acids. The paraffine oxidation is only of significance in the East-ern European countries and in China.
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13 F32 Fatty acids
Chapter 6Technical variations and specialties
The fatty acids extracted in this way are either sold as "distilled fatty acids" ac-cording to the basic oils or fats (e.g. type coconut/palm kernel) or they are sold as single fatty acids with different degrees of cleanness by the name of "fractionated fatty acids" (e.g. caproic acid above 99%).By the name ”stearine” a mix of palmitic acid (C 16) and stearic acid (C 18) is meant. In former times this solid fatty acid mixture was made mainly from beef tal -low. Nowadays the stearines are also extracted from hardened palm oil-, fish oil- and rape oil fatty acids.”Oleine” is the technical term for the oleic acid (C 18/1). This liquid product is made from beef tallow, but also from vegetable oils as palm kernel oil, palm oil and linseed oil (partly hardened).One example of the technical variations of fatty acids is the transformation of unsatu-rated components into saturated ones. This procedure is called fat hardening or hy-drogenation. By the attachment of hydrogen to a double bond, this is transformed into a single bond.
C... C
H
C
H
HH
C
H
C
H
H
H
C
H
...
+ H HC... C
H
C
H
HH
C
H
C
H
H
C
H
...
H
Fig. 17 Fat hardening (hydrogenation)
Depending on the desired degree of saturation, the addition of hydrogen can be dosed. In this way, fatty acids can either completely or only partly are hardened. By the hardening (hydrogenation) the C-chain spectrum of fatty acid mixes changes that make them easier to split up.
distribution of the C16 C18 C18/1 C18/2 C18/3 C20
c-chains
soya oil fatty acids 8 4 28 53 6 1
partial
hydrogenation 8 46 40 5 -- 1
complete
hydrogenation 8 91 -- -- -- 1
Fig. 18 Change of the c-chain distribution by fat hardening
F32 Fatty acids
Even the properties of the fatty acids change with the hardening. Hardened fatty acids are of a lighter color, more color stable and less sensitive to oxidation, i.e. they are easier to store. With the advanced hardening the solidification point (Titer) rises, whereas the iodine value falls. For margarine, as an example, often-liquid vegetable
oils are used, which then are hardened to the right consistency.Multiple unsaturated fatty acids can also be modified in another way: by conjuga-tion. After this technical operation the double bonds that were in a long distance from each other are now accumulated and only separated by a single bond.
C
H
H
C
H
H
C
H
H
O HC
O
C
H
H
C
H
H
C
H
C
H
C
H
C
H
C
H
H
C
H
H
C
H
C
H
C
H
H
C
H
H
C
H
H
C
H
H
15 12 9 9,12,15 - Octadecatrien acid
H
C
H
H
C
H
H
C
H
H
O HC
O
C
H
H
C
H
H
C
H
H
C
H
H
C
H
C
H
C
H
C
H
C
H
C
H
C
H
H
C
H
H
C
H
H
C
H
H
13 11 9 9,11,13 - Octadecatrien acid
H
Fig. 19 Conjugation of linolenic acid
This shift of the double bonds is achieved with the help of special alkaline catalysts at temperatures of about 200 to 300 °C and an appropriate pressure at the step of saponification and following deacetylation.The conjugated fatty acids react faster and get easier linked with each other, that is why they are used e.g. in the production of polyurethane foams.Reactions in which only the arrangement of the single atoms is changed, but in which the number and kind of atoms remain the same are called isomerizations (Greek: isos: same, meros: part). Aside from the conjugation another type of isomer-ization can be carried out with fatty acids. Natural unsaturated fatty acids have often got a cis-configuration, i.e. two hydrogen atoms at the double bond show in the same direction.With the help of catalysts (e.g. selenium) the unsaturated fatty acids are transformed into the trans-configuration i.e. the two hydrocarbon atoms at the double bond are on the opposite of each other.
elaidic acid trans-configuration melting point: 44,5°C
C
H
H
C
H
H
C
H
H
O HC
O
C
H
H
C
H
H
C
H
H
C
H
H
C
H
H
C
H
H
C
H
H
C
H
H
C
H
C
H
C
H
H
C
H
H
C
H
H
C
H
H
H
oleic acid Cis-configuration melting point: 16,3°C
C H COOH17 35
C
H
H
C
H
H
C
H
H
O HC
O
C
H
H
C
H
H
C
H
H
C
H
H
C
H
H
C
H
H
C
H
H
C
H
H
C
H
C
H
C
H
H
C
H
H
C
H
H
C
H
H
H
Fig. 20 Cis-trans-isomerization
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15 F32 Fatty acids
By this cis-trans-isomerization the fatty acid changes its physical properties. In the single unsaturated C 18-fatty acid the oleic acid (chemical name: cis-octradecenic acid) has got a melting point of 16,3 °C, whereas the elaidic acid (chemical name: trans-octadecenic acid) has got a melting point of 44,5 °C.
Another type of isomerisation is the production of iso-stearic acids. In this process oleic acid (C 18/1) is treated with catalysts and high temperatures, which leads to a branching of the hydrocarbon chain. After this the double bond is transferred into a single bond with the help of hydrogen.
C
H
H
C
H
H
C
H
H
O HC
O
C
H
H
C
H
H
C
H
H
C
H
H
C
H
H
C
H
H
C
H
H
C
H
H
C
H
H
C
H
H
C
H
H
C
H
H
C
H
H
C
H
H
iso-stearic acid
H
C
H
H
C
H
H
C
H
H
O HC
O
C
H
H
C
H
H
C
H
H
C
H
H
C
H
H
C
H
H
C
H
H
C
H
H
C
H
H
C
H
H
C
H
H
H
C HH
C HH
C HH
stearic acid
C H COOH17 35
Fig. 21 Isomerization of stearic acid
The iso-stearic acids are a by-product of the dimerization of oleic acid. Dimer fatty acids are dicarbonic acids, i.e. fatty acids that have two carboxylic groups (see chapter 2). They result from the fusion of two single fatty acids and have thus the double number of carbon atoms. The carbon chain of the dimer fatty acids can have a branched or a ring-shaped structure.
tall oil fatty acids/oleic acid
Monomer fatty acid Dimer fatty acid Trimer fatty acid
Isostearic acid
liquid, saturated, liquid, high molecular weight
oxidation stable
Applications: lubricants, cosmetics, dimer acid ethoxylates, cooling lubricant
Parameters: pure clay, 260°C
Fig. 22 Dimerization of oleic acid
At the dimerisation that is carried out with special catalysts at temperatures between 180° and 300 °C, apart from the dimer fatty acids and the iso-stearic acids also trimer fatty acids result. They have three times as many carbon atoms as the basic fatty acids and three carboxylic groups.
F32 Fatty acids
Other specialities that can be made of fatty acids are the azelaic acid (chem. name: nonanoylic acid (C 9):
C
H
H
C
H
H
C
H
H
O HC
O
O C C
H
H
C
H
H
C
H
H
C
H
H
H
O
Fig 23 Structure of the azelaic acid
and the pelargonic acid (chem. name: nonanic acid C 9)
C
H
H
C
H
H
C
H
H
O HC
O
C C
H
H
C
H
H
C
H
H
C
H
H
H
H
H
Fig. 24 Structure of the pelargonic acid
The production of these ozone acids is carried out by the effect of oxygen (O) on the double bonds of the oleic acid (C 18/1): The hydrocarbon chain of the oleic acid is split up and two C 9-fatty acids result.
Also the ricinoleic acid (chem. name: 12-oxy-octadecene acid) offers possibilities for modification because of its hydroxyl group (OH) at the 12th carbon atom (see page 6).E.g. by hardening (transition from the double bond into a single bond by the attachment of hydrogen) a 12-oxy-octadecene acid becomes a 12-oxy-octadecane acid, also called 12-oxy-stearic acid or hardened ricinoleic acid.Another technical variation is the dehydration, i.e. a separation of water.
C... C
H
C
H
H
C
H
C
H H
C
H
...
_C... C
H
C
H
HH
C
H
C
H
O
C
H
...
H
H
H H
O
H
H
Fig. 25 Dehydration
In this way, from the 12-oxy-octadecenic acid an octadecadienoic acid is made that belongs to the conjugated fatty acids.
Chapter 7
16
17 F32 Fatty acids
Application areas
The distilled fatty acids based on coconut oil, palm kernel oil, palm oil and tallow fatty acid and the multiple unsaturated fatty acids based on cotton, peanut, sunflower, soya bean and rape seed oil can - after neutralization with potash lye or caustic soda - be used for toiletry soaps, soft soaps, defoaming soaps in detergents and polishing pastes.
By the reaction with lithium-, aluminum- or calcium oxides one gets metal soaps that are applied as lubricating fats and cold forming agents in the metal and plastics in-dustry.
By the processing to yield alkyd resin they are used in the varnish and color industry. They can be refined to yield fatty acid alkanol amides, fatty acid ethoxylates and partial esters and then they function as emulsifiers or low foaming cleaners. From fatty acids furthermore fatty amines and amides are produced as PVC-lubricat-ing agents.
From stearines (mixture of palmitic acid C 16 and stearic acid C 18) e.g. candles, lu-bricating grease, vulcanizing catalysts for the rubber industry, cosmetics, pharmaceuticals, detergent ingredients and deinking agents for the paper industry are made.
From oleines (technical oleic acid C 18/1) e.g. soft soaps, basic material for the pro-duction of fabric softeners, defoaming agents for the paper- and nutrition industry, hair dyeing products, auxiliaries for the plastics- and rubber industry, flota-tion auxiliaries for the mining industry and textile auxiliaries are made.
With the fractionated fatty acids the application areas can be determined by the chain length:
C 6 - 10 fatty acids are used as aromatic agents, essences, humectants and sepa-rating agents in the nutrition industry, as skin oils in the cosmetic industry, for the surface treatment of tin foils and as a lubricating agent in the metal industry.C 12 fatty acids are used e.g. after further treatment as emulsifiers and starters at the production of PVC and as surfactants in detergents and cleaners.C 14 fatty acids are used e.g. after refinement processes as soap for shaving foams, as a special cleaning agent and as raw material for detergents and cleaners.C 16 fatty acids can be applied - after esterification - as vitamins in animal feed and as lubricating agent.C 18 fatty acids are applied to inhibit the depositing of solid components e.g. in fer-tilizers, pesticides, colors and varnishes or also as chlorides in the paper industry.C 22 fatty acids may also be used in the paper industry, in an amidated form as PVC-lubricant or in the production of candles.Erucic acid - C 22/1 fatty acid is e.g. used (like C 22 saturated) after an amidation in the plastics industry as lubricant in the PVC-production.
F32 Fatty acids
The conjugated fatty acids are often used as raw material for the production of polyurethane foam.
Dimer and trimer fatty acids play an important role in the production of polyamides. They are applied e.g. in fusion adhesives, sealing materials and printing inks.
In the production of polyamides the azelaic acids are also used. The azelaic and pelargonic acids can furthermore be processed to yield alkyd resins, softeners and fragrances.
Chapter 8Market data
Worldwide the capacity for fatty acid was 5,48 million tons in the year 2000. The prognoses for the year 2003 are 6,375 million tons. The utilisation was very low at 4,3 mill tons. The effective capacity is the economic usable value.
In 2000 Asia held the top position with 2,713 million tons, followed by Western Eu-rope with 1,682 million tons and North America with 1,085 million tons.
World Fatty Acid Capacities, 2000/2003,́000 mt
2000 2003
Capacity Capacity
WE 1.682 1.732
Asia 2.713 3.481
America 1.085 1.162
World 5.480 6.3750
1000
2000
3000
4000
5000
6000
7000
2000 2003
5.480
6.375
effective Capa = 4.3 mill. mt; Demand ca. 3,8 mill. mt
Fig.26 Fatty acid capacities by continents, 2000 / 2003, ‘000 mt
Prognoses are also made for the application areas of the fatty acids. Nowadays most of the fatty acids are used in the production of fatty alcohols, amides, esters and metal soaps (35-40%) and of detergents, soaps and cosmetics (30-40%). On these markets a growth is expected.
18
19 F32 Fatty acids
The production of alkyd resins and candles and the application in the color-, rubber- and tire industry is regarded as declining, while the need of the textile-, leather- and paper auxiliary markets stagnate. The application of fatty acids in lubricants is going to increase.
All in all an annual growth rate of 2 to 3 % is expected.
The worldwide biggest four fatty acid producers are Uniqema, Cognis, Akzo and the Acidchem. Furthermore there are the Hindustan Lever and the company Oleon at the fatty acid market.
F32 Fatty acids
Chapter 9Trade Names at Cognis
The product name for Fatty Acid at the European and Asian Market is Edenor. This product group is divided into following groups:
Distilled Fatty Acids; based on coconut or palm kernel oil are Edenor K, Ede-nor KPK types.
Distilled Fatty Acids; based on tallow are Edenor Edenor Ti types. Polyunsaturated Fatty acids named are Edenor plus abbreviations. Conjugated Fatty Acids are Edenor UKD types. Stearines are Edenor ST types or Edenor FHTi types. Oleins are Edenor TiO5, FTi, LCU, PK1805 and NSb types. Fractionated Fatty Acids are Edenor types plus the abbreviation of the fraction
and the C-chain distribution in percent, i.e. Edenor C12 98-100.
Cognis Corp. uses other Trade Names for Fatty Acids. Also they produce special Fatty Acids, which are explained in chapter 6. Their product names are divided into following groups:
Stearic Acids & Isostearic Acid Oleic & Polyunsaturated Acids Coconut Fatty Acids Tallow Fatty Acids Fractionated Fatty Acids Food Grade Fatty Acids
For this product groups they use the Trade Names Emersol and Emery. The Trade Names for the Dimer, Trimer and Polybasic Acids are Empol, i.e. Empol 1040 Trimer. Azelaic Acids are Emerox types and the Perlagonic acid is the Emery 1202 type.
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21 F32 Fatty acids
Chapter 10Keywords
The keyword list might be helpful for learning. With adding one sentence or explana-tion to each word, one will get a good summary of the present topics..
Sources in nature
Ester
Triglyceride
”Laurics”
Carboxo group
Trivial names of fatty acids
Peculiarity of the ricinoleic acid
”Physical and chemical data”
Chain distribution
Saponification value
Iodine value
Ester value
Titration
Titer
Unsaponified matter
Color measurements
Fat splitting
Saponification of oils and fats
Fractionated Distillation/Crystallisation
Fat hardening
”Conjugated Double bonds”
”Isomeric structures”
Stearine, Oleine, Paraffine
”Dehydration”
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