Development of a Scaleable Synthesis for 1,2-Bis(2-aminophenylthio)ethane (APO-Link) Used in the Production of Bismaleimide Resin

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• 作者：Crystal G. Densmore ; Hilary Wheeler ; Rebecca Cohenour ; Thomas W. Robison ; Dawud Hasam ; Blossom J. Cordova ; Peter C. Stark ; Edward N. Fuller ; Charles J. Cook ; Holly A. Weber
• 刊名：Organic Process Research & Development
• 出版年：2007
• 出版时间：November 2007
• 年：2007
• 卷：11
• 期：6
• 页码：996 - 1003
• 全文大小：155K
• 年卷期：v.11,no.6(November 2007)
• ISSN：1520-586X

文摘

The diamine reagent 1,2-bis(2-aminophenylthio)ethane is no longer commercially available but is still required for the synthesis of the bismaleimide resin, APO-BMI, used in syntactic foams. In this work, we examined the hydrolysis of benzothiazole followed by reaction with dichloroethane or dibromoethane. The deprotonation of 2-aminothiophenol followed by reaction with dibromoethane was also investigated and later optimized for scale-up by scrutinizing all aspects of the reaction conditions, work-up, and recrystallization. On bench-scale, the optimized procedure consistently produced a 75–80% overall yield of finely divided, high purity product (>95%). The material was also produced on both a 100 lb scale and a 200 lb scale using the optimized process, giving high quality material in excellent yield.