Study on Organo-alkali Metallic Compounds. III

Preparation of Mono- and Dicarboxylic Acids from Butadiene

Abstract

Butadiene was dimerized with sodium dispersion in THF, in the presence of catalytic amounts of o-diphenylbenzene, at various temperatures between -70 and -10°C. The reaction mixture was treated with carbon dioxide and resulting carboxylic acids were separated.
The composition of the reaction products were determined by gas chromatography. The results showed that the conversions and the composition of the carboxylic acids were depended remarkably on the dimerization temperature. The conversion to the carboxylic acids obtained to butadiene was 95%, in which C₁₀-dicarboxylic acids were contained about 85%, at-70°C. But these values decreased with increase in the dimerization temperature, and the amounts of monocarboxylic acids, in which C₉-acids were predominant, and of polybutadienes of lower molecular weights increased. The composition of the position isomers of the carboxylic acids caused by 1, 4- and 1, 2-addition of butadiene were also depended on the dimerization temperature. The amounts of n-carboxylic acids increased with decrease of the temperature.
The mechanisms of above reactions were discussed.