Fatty alcohols methyl ester process

Fatty acid esters of mono- and polyfunctional alcohols are the workhorses of oleochemistry. In many fields of application fatty acid methyl esters replace fatty adds because they are less corrosive. Chemical reactions can often be carried out under milder conditions. They have lower boiling points and require less energy to distil and to fractionate than the corresponding fatty acids. The elimination of methanol from the reaction products can be more easily achieved than that of water. Therefore fatty acid methyl esters are primarily used for the production of saturated and unsaturated fatty alcohols. Methyl esters are manufactured by acid catalyzed esterification of fatty acids in counter-current reaction columns or by alkaline transesterification starting directly from the triglyceride oils in a batch, semi-batch or continuous process (Figure 9.1.37> ° ° ... 

Fatty acid methyl esters (FAMEs) show large potential applications as diesel substitutes, also known as biodiesel fuel. Biodiesel fuel as renewable energy is an alternative that can reduce energy dependence on petroleum as well as air pollution. Several processes for the production of biodiesel fuel have been developed. Transesterification processes under alkali catalysis with short-chain alcohols give high yields of methyl esters in short reaction times. We investigated transesterification of rapeseed oil to produce the FAMEs. Experimental reaction conditions were molar ratio of oil to alcohol, concentration of catalyst, type of catalyst, reaction time, and temperature. The conversion ratio of rapeseed oil was enhanced by the alcohohoil mixing ratio and the reaction temperature. 

Fig. 36.19. Methyl ester process for production of natural fatty alcohols.

Fatty Alcohols. Fatty alcohol is considered a basic oleochemical manufactured by high-pressure hydrogenation of fatty acids or fatty acid methyl esters. The majority of the fatty alcohol produced is further subjected to various processes, such as sulfation, ethoxylation, amination, phosphatization, sulfitation, and others. 

Fats and oils are renewable products of nature. One can aptly call them oil from the sun where the sun s energy is biochemically converted to valuable oleochemicals via oleochemistry. Natural oleochemicals derived from natural fats and oils by splitting or tran -esterification, such as fatty acids, methyl esters, and glycerine are termed basic oleochemicals. Fatty alcohols and fatty amines may also be counted as basic oleochemicals, because of their importance in the manufacture of derivatives (8). Further processing of the basic oleochemicals by different routes, such as esterification, ethoxylation, sulfation, and amidation (Figure 1), produces other oleochemical products, which are termed oleochemical derivatives. 

Similarly, fatty alcohols with chain length from C12 to C22, which are industrially produced by hydrogenation of fatty acid methyl esters are efficient internal lubricants and exhibit good compatibility with PVC. However, they also have the disadvantage of high volatility under plastics processing conditions. 

Conventional technology of the hydrogenolysis of fatty acid methyl esters to the corresponding fatty alcohols uses copper chromite or zinc chromite based catalysts and the manufacturing process requires high pressures (200-300 bar) and temperatures (250-300 °C). The activity of copper chromite catalysts was significantly increased by the addition of zinc. ... 

At the end of the reaction, excess methanol is partly distilled off. The mixture of fatty acid methyl ester and glycerol is pumped into a settling tank to allow phase separation. After standing for several hours, the lower phase (glycerol phase) is separated. The upper ester phase is removed and temporarily stored before further processing (e.g., hydrogenation to fatty alcohols). 

Fatty acid methyl esters are now the main intermediates in oleochemistry. Epox-idation can be considered as a transformation currently applied to triglycerides that is easy to perform on an industrial scale, compared with the production process for fatty alcohol. Therefore, why should epoxidized fatty acid methyl esters not become one of the commodities of the future The commercial development of these compounds requires easy, environmentally friendly (e.g., avoiding catalyst use) routes of low production cost as well as identified industrial outputs. Such considerations were taken into account in this study both rapeseed methyl esters (RME) and high-oleic sunflower methyl esters (HOSME) were used as starting materials. 

Volatilization of the lipstick using the Py-GC process indicates the presence of cetyl acetate (CA) and isopropyl myristate (1PM). Heptanal (C-7AL), a pyrolysis product of castor oil, is a major product. The THM profile in this case is more complex and gives more information about the composition of the product. Cetyl acetate is converted to the methyl ether of cetyl alcohol (C-16-OME), while IPM is partly converted to the methyl ester. The major components, RIC-OME and RIC, are identified as the methyl ether of ricinoleic acid methyl ester and ricinoleic acid methyl ester having a free OH group, respectively. These compounds result from hydrolysis and complete or partial methylation of the major component of castor oil. C8.0 and CIO.O are fatty acid methyl esters that indicate the presence of coconut oil in the formulation. This product was differentiated from more than 60 lipsticks examined in the study, on the basis of the compositon of the organic components. 

The commercial manufacture of fatty alcohols started in the late 1920s. The very first natural fatty alcohol was obtained by a simple ester cleavage of oil originating in the skull of the sperm whale. But a mere 4 years later, the first industrial-scale process had already been developed for producing a fatty alcohol from coconut fatty acid by high-pressure hydrogenation. In 1958, a route was developed from fatty acid methyl ester, which still remains the most economic method of producing... 

FAME may become in the future a possible organic feedstock to be sulphonated to Fatty Acid Methyl Ester Sulphonate (FAMES). This feedstock is naturally renewable as it is produced from oils/fats or fatty acids. There are several possible process routes for the manufacture of FAME. Transesterification of fat triglycerides is the predominant method for manufacture of mixed fatty acid methyl esters, and direct esterification of fatty acids (FA) is practised if very selective cuts of product, in general as an intermediate detergent range alcohol, are desired. Methyl cocoate is a mobile, oily liquid above 25"C with a yellow tint and a characteristic fatty acid pungent odour. FAME sulphonation to FAMES is technically possible but hardly applied up to now (1990). 

In the case of base-catalyzed reactions the substrate comes into contact with either HO or any other highly electron-rich catalyst (e.g., alcoholates, strongly basic amines, metal alkyls). Again, the substrate is activated, typically via the intermediate formation of carbanion species. A technically important example of base catalysis is the transesterification of natural oils to fatty acid methyl esters (FAME, better known as biodiesel ), a process typically catalyzed by methanolate salts. 

The main use of copper oxide/zinc oxide catalysts has been in dehydrogenation and hydrogenation reactions. These include the dehydrogenation of isopropyl alcohol to acetone as well as the hydrogenation of oxo-alcohols and fatty acid methyl esters. Although in many processes copper chromite catalysts are preferred to copper oxide/zinc oxide, the environmental problems involved in disposing of chromium wastes may reverse the situation. 

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