Development of Methods for the Synthesis of Neopentyl Glycol by Hydrogenation of Hydroxypivaldehyde

Abstract

Neopentyl glycol (NPG) is a precursor for the manufacture of many valuable products of industrial importance such as polyester, polyurethane and alkyd resins, synthetic lubricants, hydraulic fluids, drugs, etc. The structure of NPG provides the resins with excellent hydrolytic stability, resistance to weather conditions, good flexibility-hardness balance, and outstanding functional properties. The paper presents a literature review on the development of methods for NPG preparation, focusing primarily on the synthesis of NPG by hydrogenation of hydroxypivaldehyde, which is obtained by the crossed aldol condensation of isobutyraldehyde and formaldehyde. Preparation of the substrates, catalysts, technical and apparatus solutions, and NPG purification were discussed.

Polymer-Supported Poly(Ethylene Glycol) as a Phase-Transfer Catalyst for Cross-Aldol Condensation of Isobutyroaldehyde and Formaldehyde

“…The demand for hydroxypivalaldehyde (HPA) continues to grow as it is a valuable intermediate for the production of many compounds of industrial importance, such as additives improving the quality of plastics, and in the production of paints, varnishes and lubricants ( Scheme 1 ) [ 1 , 2 , 3 , 4 , 5 ]. These compounds include: neopentyl glycol (2,2-dimethyl-1,3-propanodiol, NPG), which is obtained mainly by hydrogenation of hydroxypivaldehyde [ 3 , 6 , 7 ]; neopentyl glycol monohydroxypivalate, so-called Tishchenko ester (ET), obtained by HPA disproportionation (Tishchenko reaction) [ 5 , 6 ]; and spiroglycol (3,9-bis(1,1-dimethyl-2-hydroxyethyl)-2,4,8,10-tetraoxaspiro[5.5]undecane) synthesized from hydroxypivaldehyde and pentaerythritol [ 8 , 9 , 10 ]. Other compounds obtained from HPA are, among others, hydroxypivalic acid and its esters, hydroxypivalic acid lactone.…”