PRODUCTION OF 4,4'-DIHYDROXYDIPHENYL ETHERS

• Main Author: UOHAMA MISAO
• Format: Patent
• Language: English
• Published: 09.01.1992
• Subjects: ACYCLIC OR CARBOCYCLIC COMPOUNDS; APPARATUS THEREFOR; CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOIDCHEMISTRY; CHEMISTRY; GENERAL METHODS OF ORGANIC CHEMISTRY; METALLURGY; ORGANIC CHEMISTRY; PERFORMING OPERATIONS; PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL; THEIR RELEVANT APPARATUS; TRANSPORTING

PURPOSE:To easily obtain the subject compound useful as a raw material for heat-resistant polymer in high selectivity with simplified post-treatment of the reaction product by carrying out dehydrative dimerization of a hydroquinone compound in a solvent in the presence of a heteropolyacid as a catalyst. CONSTITUTION:The objective compound having a purity of >= 99 mol% can be produced with simple procedures by reacting 100 pts. wt. of a hydroquinone compound (e.g. hydroquinone) in the presence of usually 1-50 pts. wt. of a heteropolyacid (e.g. silicotungstic acid or phosphotungstic acid) or its acidic metal salt catalyst in a solvent (e.g. cumene) preferably at 80-200 deg.C to effect the dehydrative dimerization of the hydroquinone compound, filtering the reaction mixture after the completion of the reaction to remove the catalyst, cooling the filtrate to room temperature, separating the precipitated crystal by filtration, washing the crystal with warm water of a moderate temperature to remove unreacted hydroquinone compound and drying the product. The catalyst may be supported on a carrier such as activated carbon and the catalyst and unreacted hydroquinone compound recovered by the above process can be continuously used in the reaction.