Synthesis, Identification, and Isolation of Esters of Pentaerythritol and Linear С4–С7 Carboxylic Acids

Various procedures for thermal esterification of individual monobasic С4–С7 carboxylic acids with pentaerythritol in an excess of the corresponding acid in the presence of a solvent or without it in combination with azeotropic distillation of water released in the reaction were studied. Four tetraesters of pentaerythritol (PE) and C4–C7 acids were synthesized, isolated, and purified (to ≥99 wt % purity according to GLC) and were identified by GC–MS. The physicochemical characteristics of the products were determined. The dependence of the induction effect determined by the alkyl chain length in the acid molecule on the esterification rate was studied; at 100–110°C, 90% yield was reached in 30 h for PE tetrabutyrate and in 13–14 h for С5–С7 tetraesters. The purity of the tetraesters was higher than 99 wt % after the purification, and the yield was 78–85%.