1. Lewis acid solid catalysts for the synthesis of methylenedianiline from aniline and formaldehyde
- Author
-
Alvaro Gordillo, Dirk De Vos, Patrick Tomkins, Trees De Baerdemaeker, Ka Yan Cheung, Carlos Marquez, and Andrei-Nicolae Parvulescu
- Subjects
ZEOLITE CATALYSTS ,Technology ,Engineering, Chemical ,Polyurethane ,Formaldehyde ,010402 general chemistry ,01 natural sciences ,Catalysis ,DIPHENYL METHANE DADPM ,chemistry.chemical_compound ,Aniline ,Engineering ,Aminal ,Organic chemistry ,Methylenedianiline ,Lewis acids and bases ,Physical and Theoretical Chemistry ,skin and connective tissue diseases ,Science & Technology ,010405 organic chemistry ,Chemistry, Physical ,Diaminodiphenylmethane ,Lewis acid ,0104 chemical sciences ,Chemistry ,chemistry ,Yield (chemistry) ,Physical Sciences - Abstract
A catalyst containing Hf4+ and Zn2+ supported on silica has been found to be highly effective for the synthesis of methylenedianiline (MDA), an indispensable precursor in the polyurethane industry. Its performance was further improved when the silica support was replaced by silica-alumina, which resulted in a catalyst that was both active and selective, as indicated by the high MDA yield and high 4,4′–MDA/(2,2′–MDA + 2,4′–MDA) isomer ratio obtained. Furthermore, the catalyst also gave an appreciable oligomeric MDA (OMDA) yield and was noticeably more stable than the zeolites that were used in comparative tests: it could be used in at least five consecutive runs without any significant loss in activity. The combination of Bronsted and Lewis acidity strongly increases the overall activity and yields a catalyst that represents a remarkably stable and reusable alternative to the commonly studied systems for this reaction.
- Published
- 2021