Azelaic acid double bond cleavage

The diacids for these polymers are prepared via different processes. Azelaic acid [123-99-9] for nylon-6,9 [28757-63-3] is generally produced from naturally occurring fatty acids via oxidative cleavage of a double bond in the 9-position, eg, from oleic acid [112-80-1]... 

On an industrial scale, the traditional method for cleavage of carbon-carbon double bonds is ozonolysis, used for the manufacture of azelaic acid and nonanoic acids from oleic acid, and of butane tetracarboxylic acid from tetrahydrophthalic anhydride. The process is effectively a quantitative and mild process.178 However, it is capital and energy intensive. The intermediate ozonide is worked up either reductively or oxidatively to produce the aldehyde, ketone or carboxylic acid. Hydrogen peroxide is the common oxidizing agent used in the second step.179-181 Oxygen can also be used either alone182 or in combination with zeolites.183 Reviews on ozonolysis are available and the reader is directed to reference 184 for further information. 

The cleavage of oleic acid to azelaic acid and pelargonic acid with ozone as oxidant is one of the important industrial applications of ozonolysis [2]. However, finding a catalytic alternative to this unsuitable and hard-to-handle oxidant is in the interests of research groups all over the world. The cleavage of internal C=C double bonds by use of a Re, Mo, or W catalyst with H2O2 as oxidant, or a Ru catalyst with peracetic acid [12], is known. 

Oxidative cleavage of the double bond in tall oil derived fatty acid may be carried out with ozone pelargonic and azelaic acids are the major acids formed (36). 

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