High-Boiling By-Products of the Synthesis of Trimethylolpropane and Their Processing into Esters

Abstract— According to the data of ¹H NMR spectroscopy, trimethylolpropane, di(trimethylolpropane), linear formals, and structures including a fragment of a cyclic formal are the main components of the bottom residue after vacuum distillation of raw trimethylolpropane yielded in the technological process of n-butyral condensation with formaldehyde proceeding by the Cannizzaro–Tishchenko reaction. The content of other impurities is minor. The heavy bottoms can be converted in high yield to a mixture of esters of trimethylolpropane and di(trimethylolpropane) by esterification with n-pentanoic acid. Such esters are characterized by a low pour point, high chemical resistance, thermal stability, and good viscosity-temperature properties, as well as sufficient compatibility with various plastic materials, and therefore, can be employed as lubricants, polymer plasticizers, and other products.