PROCESS FOR THE PRODUCTION OF A SULFONE MONOMER

摘要

The present invention provides a method for the preparation of polymer grade 4,4'-dichlorodiphenyl sulfone in steps comprising reacting dimethyl sulfate and sulfur trioxide optionally containing a catalyst; reacting the formed dimethyl pyrosulfate with the unreacted sulfur trioxide optionally in the presence of a catalyst; reacting the reaction mixture with monochlorobenzene optionally containing a catalyst; optionally removing unreacted dimethyl sulfate; isolating crude 4,4'-dichlorodiphenyl sulfone using an organic solvent / organic solvent - water mixture; recovering the solvent from mother liquor; optionally recovering the isomeric mixture of dichlorodiphenyl sulfones from mother liquor; optionally, conversion of residual isomeric mixture of dichlorodiphenyl sulfones to a product selected from diphenyl sulfone, 2-aminodiphenyl sulfone; 2,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxydiphenyl sulfone; optionally recovering monochlorobenzene sulfonic acid and/or monochlorobenzene from the mother liquor; optionally recovering sulfuric acid from the residual liquor; optionally recycling the solvent; and purifying 4,4'-dichlorodiphenyl sulfone from crude followed by crystallization. Further the present invention discloses a process in which isomeric mixture of 4,4'-, 3,4'-, and 2,4'-dichlorodiphenyl sulfone produced during the preparation of 4,4'-dichlorodiphenyl sulfone is converted to value added products such as diphenyl sulfone, 2,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxydiphenyl sulfone and 2-aminodiphenyl sulfone.