Stearic oxidative decarboxylation

Alpha oxidation and omega oxidation. Animal tissues degrade such straight-chain fatty acids as palmitic acid, stearic acid, and oleic acid almost entirely by (3 oxidation, but plant cells often oxidize fatty acids one carbon at a time. The initial attack may involve hydroxylation on the a-carbon atom (Eq. 17-3) to form either the d- or the L-2-hydroxy add.17 18-32 323 The L-hydroxy acids are oxidized rapidly, perhaps by dehydrogenation to the oxo acids (Eq. 17-3, step b) and oxidative decarboxylation, possibly utilizing H202 (see Eq. 15-36). The D-hydroxy acids tend to accumulate... 

Carboxylic acids are thermally stable. Decarboxylation of carboxylic acids is observed at 600 K and higher in the absence of dioxygen [4], At the same time, the decarboxylation of fatty acids in oxidized cumene was observed at 350 K [71]. The study of C02 production from oxidized acetic, butanoic, isobutanoic, pentanoic, and stearic acids labeled with 14C in the... 

The thermal decarboxylation of a mixture of barium salts has been used to prepare unsymmetrical ketones the yields are not stated. The earlier procedure has been modified by carrying out the reaction in vacuo in an iron flask. Glass reaction vessels are inferior. In this manner, a large number of the high-molecular-weight methyl ketone s, C9, C,o, C,j-C , and C, are prepared in 54-67% yields. Cyclopentanone has been synthesized in 80% yield by distillation of adipic acid from barium hydroxide at 295°. In a study of metallic oxides and carbonates, magnesium oxide is preferred for the liquid-phase ketonization of stearic acid at 330-360° (95%). A convenient method for the preparation of dibenzyl ketone is the reaction of phenylacetic acid, acetic anhydride. 

There are some complicating factors, notably temperature. Stearic acid vapor reacts with activated aluminum oxide to form an aluminum stearate which is tenaciously retained by the adsorbent. On raising the temperature of the system, the desorbed material is not stearic acid but decarboxylated, cracked olefinic hydrocarbons. 

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