1969 年 48 巻 5 号 p. 286-294
Carboxylation of zso-butene with carbon monoxide and water to produce branched C5 acid (trimethyl acetic acid) as the main product was studied under various reaction conditions in the presence of concentrated sulfuric acid. The aim of this work was to observe the influence of reaction conditions, such as the catalyst acid concentration, and the amount of the catalyst, reaction temperature, the amount of the solvent (n-hexane) etc, on the yield of carboxylic acids.
High carbon monoxide pressure favored carboxylation between 10kg/cm2 and 50 kg/cm2, and the yield of carboxylic acids increased with the decrease of reaction temperature between 4 and 93°C
Carboxylation was predominant under the sulfuric acid concentration of 90% and higher. However, the yield of carboxylic acids decreased under the acid concentration of 98% and higher, presumably due to the lack of water in the reaction zone which is necessary to stabilize the carboxylated intermediates. Under the acid concentration below 93%, the produced carboxylic acids showed the increasing tendency to dissolve in n-hexane solvent with the decrease of the acid concentration.