PROCESS FOR PREPARING 3,4-DIHYDROXY-5-NITROBENZALDEHYDE

摘要

The invention relates to a process for preparing 3,4-dihydroxy-5-nitrobenzaldehyde consisting in bringing into reaction 3-ethoxy-4-hydroxy-5-nitrobenzaldehyde and a mixture containing zinc chloride, water and chlorine hydride, at a temperature of 70...130 C, at a zinc chloride/3-ethoxy-4-hydroxy-5-nitrobenzaldehyde weight ratio of 1.5...25/1 and a chlorine hydride/zinc chloride volume/weight ratio of 0.17...0.6/1, at a chlorine hydride concentration of 10...40%, the raw reaction product being crystallized from toluene.