純ナフテン系炭化水素の液相空気酸化による低級脂肪酸の生成について

抄録

The authors investigated the possibility of producing lower fatty acids by liquid phase air oxidation of pure naphthenic hydrocarbons, such as cyclopentane (I), methylcyclopentane (II), cyclohexane (III), methylcyclohexane (IV), ethylcyclohexane (V), o-(VI), m-(VII), p-dimethyl-cyclohexane (VIII), and isopropylcyclohexane (IX). Any reports on the application of these naphthenic hydrocarbons as raw materials for the manufacture of lower fatty acids have not been noted.
The oxidation was carried out under the following conditions:
A B
React. temp. 160°C 160°C
Catalyst None Manganese Naphthenate (0.01wt% as Metallic Mn)
React. time 6hr 6hr
Oxidizing agent Air Oxygen
Max partial press. of O₂ (calculated for 0°C) 4.5atm 4.5atm
It was found that the oxidizability and the compositions of the products were greatly affected by the structure of hydrocarbons.
The naphthenic hydrocarbons having methyl or ethyl side chain showed better oxidizabilities and higher yield of lower fatty acids than those without side chain. For instance, when (VIII) was oxidized under the above condition A, 96% conversion was obtained and total the yield of formic acid and acetic acid was 74.5% based on the reacted hydrocarbon. The yield of dibasic acids, however, were greater from naphthenic hydrocarbons without side chains than those with methyl or ethyl side chains. When the side chain is linked with tertiary carbon (IX) the oxidizability was very different from other cyclohexanes with side chain and gave low yield of lower fatty acids. It has been observed that the ratios of (acetic acid)/(formic acid) obtained from naphthenic hydrocarbons are affected by their molecular structures and increased according to the kind of side chain in the following order: (III)=(IX)<<(VIII)<(IV)<(V)<(VII)<(VI). Some considerations were made on these phenomena.