申请人:Occidental Chemical Corporation
公开号:US05322954A1
公开(公告)日:1994-06-21
Disclosed is a method of making a 4-substituted phthalic anhydride. A halomaleic (including halofumaric anhydride (or the acid or ester thereof) is made by the reaction of-maleic anhydride with chlorine or bromine. The halomaleic anhydride is reacted with a conjugated diene to form a first cycloadduct having the formula ##STR1## The first cycloadduct is heated to eliminate HX and produce a second cycloadduct having the formula ##STR2## The second cyclo adduct is dehydrogenated to produce a 4substituted phthalic anhydride which has the formula ##STR3## where R.sub.1, R.sub.2, and R.sub.4 are preferably H and R.sub.3 is preferably Cl or F.
披露了一种制备4-取代邻苯二酐的方法。通过将卤代马来酸酐(包括卤代顺丁二酸酐(或其酸或酯))与氯或溴反应制得,然后将卤代马来酸酐与共轭二烯反应形成具有以下结构的第一环加成物:第一环加成物加热消除 HX 生成具有以下结构的第二环加成物:第二环加成物脱氢生成4-取代邻苯二酐,其化学式为:其中 R.sub.1、R.sub.2 和 R.sub.4 优选为 H,R.sub.3 优选为 Cl 或 F。