Oleochemical dicarboxylic acid

The use of oleochemicals in polymers has a long tradition. One can differentiate between the use as polymer materials, such as linseed oil and soybean oil as drying oils, polymer stabilizers and additives, such as epoxidized soybean oil as plasticizer, and building blocks for polymers, such as dicarboxylic acids for polyesters or polyamides (Table 4.2) [7]. Considering the total market for polymers of ca. 150 million tonnes in 1997 the share of oleochemical based products is relatively small - or, in other terms, the potential for these products is very high. Without doubt there is still a trend in the use of naturally derived materials for polymer applications, especially in niche markets. As an example, the demand for linseed oil for the production of linoleum has increased from 10000 tonnes in 1975 to 50 000 tonnes in 1998 (coming from 120000 tonnes in 1960 ) [8a]. Epoxidized soybean oil (ESO) as a plastic additive has a relatively stable market of ca. 100000 tonnes year-1 [8b]. 

Oleochemical based dicarboxylic acids - azelaic, sebacic, and dimer acid (Figs. 4.5 and 4.6) - amount to ca. 100000 tonnes year-1 as components for polymers. This is about 0.5% of the total dicarboxylic acid market for this application, where phthalic and terephthalic acids represent 87%. The chemical nature of these oleochemical derived dicarboxylic acids can alter or modify condensation polymers, and, used as a co-monomer, will remain a special niche market area. Some of these special properties are elasticity, flexibility, high impact strength, hydrolytic... 

Oleochemicals as Starting Materials for the Synthesis of Dicarboxylic Acids 81... 

As oleochemicals for the preparation of dicarboxylic acids we did not choose natural C18- or C22-fatty acids with an internal double bond (oleic-, erucic acid),... 

Oxidation of unsaturated oleochemicals can proceed in different ways, and yields numerous products. Typical oxidations of fatty acids are, for instance, ketoniza-tions yielding keto acids [72, 73], hydroxylations to bishydroxy acids [74], epoxida-tions to epoxy acids [75-78] and oxidative splitting reactions [72, 74] yielding mixtures of mono- and dicarboxylic acids. However, not only the double bond but also the functional group of the fatty compound, can be oxidized. One example is the ruthenium-catalyzed oxidation of fatty alcohols to fatty aldehydes or fatty acids... 

The yield of AA was 44- 54%. The method has the advantage that the use of in 5 tM-generated peracid is an established method in the oleochemical industry. Fujitani etal. prepared pure DSA as reported in [93] and cleaved it using Co(OAc)2 to 95% yield of dicarboxylic acids (AA and suberic acid). The method failed if technical DSA was used. However, this substrate was converted to AA and suberic acid in the presence of Co(OAc)2 -Mn(OAc)2 -HBr with a yield of 84%. A similar method was claimed in a Soviet patent [94]. 

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