4,4'-бифенол

Химические свойства

Powder

Использование

4,4'-biphenol be used intermediate liquid crystal polymers raw materials. Synthetic polymers, due to its excellent heat resistance, it is used as polyester, urethane modified monomer, polycarbonate, polysulfone, and epoxy resin, for the manufacture of an excellent engineering plastics and composite materials. Antioxidant antioxidants for rubber and plastics. Dye intermediates or petroleum products stabilizer.

Методы производства

4,4'-Biphenol can be synthesized in excellent yields by debutylation of 3,3',5,5'-tetra-tert-butyl-4,4'-dihydroxybiphenyl. Other production processes are the alkaline fusion of 4,4'-biphenyldisulfonic acid, the boil down of benzidinebisdiazonium salts, and the decarboxylation of 4,4'-dihydroxybiphenyl-2-carboxylic acid. Symmetrically alkylated 4,4'-dihydroxybiphenyls such as 4,4'-dihydroxy-2,2',3,3',5,5',6,6'-hexamethylbiphenyl are preferably obtained by the oxidative coupling of the corresponding substituted monophenols. Here, diphenoquinones are generally formed in the first step which must be reduced. Phenol itself always gives isomeric mixtures of dihydroxybiphenyls on coupling with various oxidants. These mixtures are also formed by alkaline fusion of 4,4'-dihydroxybiphenylsulfone.

Определение

ChEBI: A member of the class of hydroxybiphenyls that is biphenyl with hydroxy groups at positions 4 and 4'.

Профиль безопасности

Poison by intraperitoneal route.Moderately toxic by skin contact. Mildly toxic byingestion. Human mutation data reported. When heated todecomposition it emits acrid smoke and irritating fumes.

Методы очистки

Recrystallise the biphenol from aqueous EtOH preferably under N2 to avoid oxidation to the extended qiunone. It is characterized as the dimethyl derivative (4,4’-dimethoxybiphenyl) from which it is prepared by demethylation. The dimethoxy derivative has m 176.5-177o (from AcOH, EtOH, hexane or *C6H6) and sublimes in vacuo. [Williamson & Rodebush J Am Chem Soc 63 3019 1941, Beilstein 6 I 485, 6 II 962, 6 III 6389, 6 IV 6651.]