Oleochemistry
The oleochemical industry is a branch of chemistry that deals with the study of plant and animal fats, their derivatives, as well as with the product equivalents petrochemically. Since the oleochemicals primarily concerned with the chemistry based on renewable resources, it is also closely linked with the concept of sustainability.
Vegetable and animal fats are used in the chemical referred to as triacylglycerols ( triglycerides), as they consist of a glycerol moiety via ester bonds to the three fatty acid residues are bound. The fatty acid residues consist of saturated, mono- or polyunsaturated, branched or unbranched, or otherwise modified carbon chains having about 10 to 20 or more carbon atoms, so that a wide range is provided. The oleochemical industry deals with these compounds and derived substances and the corresponding chemical reactions and production processes.
- 4.2.1 metathesis
- 4.2.2 epoxidation
History
Oils and fats are an important and high-energy components of the human diet. But the material use is historically significant. As the first oleochemical application of oils and fats, the production of soaps are considered. Breakfast was already the energy use for example as fuel for oil lamps known.
In the 19th century began the modern oleochemicals and there was a systematic study of the properties and chemical reactions. Nowadays, the oleochemicals is represented in many areas of life such as food manufacturing, cosmetics, pharmaceuticals as well as for the production of basic industrial chemicals as well as in the energy sector in the production of biofuel biodiesel. About one- seventh of the amount of oils and fats produced globally is processed oleochemical.
Raw material base
The naturally occurring fats and oils primarily differ in the chain length distribution and the number of double bonds in the carbon chain. Soybean oil was in 2000 with a share of 29 % worldwide in front of palm oil and rapeseed oil, the most widely produced vegetable oil. The total consumption was 87.2 million tons in 2000.
The following table shows the proportions of the different fatty acid residues in triglycerides industrially important fat in percent, in brackets, the number of carbon atoms and double bonds in the molecule.
Applications
Renewable resources currently cover about ten percent of the raw material needs of the chemical industry, of which a large part of oleochemicals. A quantitatively the largest applications is the production of biodiesel by transesterification with methanol nowadays.
The production of surfactants from the fatty acid lauric acid to sodium lauryl sulfate (nonionic surfactants ), an important ingredient in many skin care products, is a large-scale process. On sugar surfactants ( nonionic surfactant), the fatty acid is bound to a sugar. Other applications include the production of lubricating oils, solvents and bio-and copolymers for the plastics and coatings sector. Glycerin is used in many ways in the cosmetics sector. Since it is available through the biodiesel production in large quantities, but it is also used as animal feed, energy and used elsewhere.
Chemical Processes
Oleochemicals usually takes place at the carboxy group (-COOH ) functional group of fatty acids. So far, the chemistry of the fatty acid chain with the exception of the castor oil, the fatty acid chain having a hydroxy group by nature, only a limited use. Their research could be a great technical potential and through programs of the Federal Ministry of Food, Agriculture and Consumer Protection (BMELV ) support.
The biogenic origin of these oils ideal for biotechnological implementation, which is far too little research.
Reactions at the carboxy group
Hydrolysis
Hydrolysis of triglycerides fatty acids and glycerol are obtained:
The reaction can be carried out both acid and base catalysis. The subsequent chemistry of the fatty acids is varied. It includes the preparation of nitriles and their derivatives, fatty acid or acid chlorides.
Transesterification
The reaction of the fats and oils with an alcohol is known as transesterification. The process is used industrially for the production of biodiesel. Also this reaction is carried out under base catalysis in the art. As a product created with the full implementation of a triacylglycerol three fatty acid methyl esters (FAME ) from which biodiesel is produced, as well as a coproduct a molecule of glycerol.
The resulting methyl esters of unsaturated fatty acids can undergo a wide range of secondary reactions, such as hydrogenation, metathesis and epoxidation.
Saponification
The hydrolysis is one of the oldest known chemical processes of mankind and has been used by the Sumerians. In this case, the triglyceride ( triesters of glycerol = ) with a base - in this case sodium hydroxide solution - the metal salt (here, sodium salt ) is reacted to the fatty acid. This soap thus obtained ( = sodium salts of fatty acids) is one of the anionic surfactants. R1, R2 and R3 organyl (alkyl or alkenyl) of fatty acids:
Hydrogenation
Hydrogenation of the methyl ester leads to fatty alcohols, which represent an important role as raw material for the preparation of anionic surfactants. By ethoxylation and subsequent sulfation with the gaseous sulfur trioxide leads to lauryl ether sulfates, which are used in the production of body care preparations.
A further application of the fatty alcohols is the preparation of the alkyl polyglycosides, a surfactant having a sugar residue ( a glucoside ) as the hydrophilic group.
Reactions the carbon chain
Metathesis
By metathesis of unsaturated fatty acid esters leads to a wide range of secondary products such as unsaturated dicarboxylic acid esters and internal olefin. By ethenolysis ω -unsaturated fatty acid esters are available, with α -olefins as a by-product. Both of these products may in turn be used as a component in the copolymerization component in the polymerization of ethylene by the Ziegler - Natta process, thus resulting in functionalized polyethylene.
Epoxidation
Unsaturated methyl esters can be epoxidized by the Prileschajew reaction with an organic peroxy carboxylic acid and can be used as PVC stabilizers or as a reactive solvent in paint chemistry.
Petrochemical Processes
The oleochemical industry is also concerned with the production of oleochemicals based on petrochemicals. An example of this is the production of glycerol from propylene over the steps of the allyl chloride, dichlorohydrin and epichlorohydrin which can be reacted with sodium hydroxide to glycerin.