Zinc Acetates as Efficient Catalysts for the Synthesis of Bis-isocyanate Precursors

Autor:	Núria Bonet, Elisenda Reixach, Anton Vidal-Ferran, Stefan Wershofen, F. Xavier Rius-Ruiz
Rok vydání:	2010
Předmět:	chemistry.chemical_classification General Chemical Engineering chemistry.chemical_element General Chemistry Zinc Isocyanate Industrial and Manufacturing Engineering Catalysis chemistry.chemical_compound chemistry Diamine Anhydrous Organic chemistry Dimethyl carbonate Alkyl
Zdroj:	Industrial & Engineering Chemistry Research. 49:6362-6366
ISSN:	1520-5045 0888-5885
DOI:	10.1021/ie100319n
Popis:	Anhydrous and hydrated zinc acetates were found to efficiently catalyze alkoxycarbonylation of the aromatic diamines 2,4-toluenediamine (2,4-TDA) and 4,4′-diphenylmethane diamine (4,4′-MDA) with diethyl and dimethyl carbonate, providing the desired bis-carbamates in yields from 93 to 98%. Driving these reactions to completion required temperatures of ca. 190 °C for 2,4-TDA and ca. 180 °C for 4,4′-MDA, and alkyl carbonate-to-substrate molar ratios of 25:1 to 30:1. Higher catalyst loadings were required for 2,4-TDA (2.5 mol %) than for 4,4′-MDA (1 mol %).
Databáze:	OpenAIRE
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