PROCESS FOR PREPARING DITERT-BUTYLSUCCINATE AND USE THEREOF FOR PREPARING 1,4-DIKETOPYRROLO-[3,4-c]-PYRROLE PIGMENTS

摘要

In the preparation of di-tert.-butyl succinate of formula (I) by proton-catalysed esterification of succinic acid (IIA) with isobutene (III), (IIA) and/or succinic anhydride (IIB) is reacted with (III) in the presence of an aqueous acidic esterification catalyst but not sulphuric acid (H2SO4) in a concentration > 95 wt.%;