Succinic acids cyclohexane-1-carboxylate

Initially, cyclohexane is oxidized to the intermediate cyclohexyl hydroperoxide, CHHP. Then, the obtained CHHP is decomposed into the desired components cyclohexanone and cyclohexanol however, it is also partly decomposed into undesired by-products. A part of the formed cyclohexanol is further oxidized to cyclohexanone and a part of the formed cyclohexanone is converted to by-products. Part of the cyclohexane oxidation by-products are further destroyed (not shown in this figure). The by-products finally obtained include, in various amounts, acids such as adipic acid, e-hydroxycaproic acid, glutaric acid, succinic acid, valeric acid, caproic acid, propionic acid, acetic acid, formic acid, and noncondensable gases such as CO and CO2. In addition, several esters are formed between mainly cyclohexanol and the various carboxylic acids. The destinations of these by-products are quite diverse and depend on the producer for example, some of these byproducts are fed to combustion units for heat recovery purposes, while others are used as feedstock for chemicals such as 1,5-pentanediol, 1,6-hexanediol (HDO), and caprolactone. In general cyclohexanol is recovered from esters in a biphasic saponification step. 

The per-pass conversion is 5-7%, to limit the consecutive reactions in fact, alcohol and ketone are more reactive towards oxygen than cyclohexane. Selectivity to the KA Oil is around 75-80% (product weight ratio Ol/One 60/40) by-products are carboxylic acids (6-hydroxyhexanoic, n-butyric, n-valeric, succinic, glutaric and adipic among others), and cyclohexyl hydroperoxide. Unconverted cyclohexane is recycled [2a, cj ... 

Nitrocyclohexane has been prepared by E. I. du Pont de Nemours Company by nitration of cyclohexane. Cyclohexane undergoes nitration and oxidation to give nitrocyclohexane and adipic acid along with smaller amounts of glutaric acid and succinic add. Nitration is accelerated by the addition of nitrogen dioxide. The process may be operated continuously in the liquid phase with 45-75 per cent nitric acid at temperatures of 100-200 C and pressures of 2-10 atm. This process is of particular interest in that oxidation products from cycloalkanes are usually S3rmmetrical di-carboxylic acids, which are of industrial importance. 

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