| 摘要 |
1509485 Stabilization of vinyl or vinylidene monomers ICI AMERICAS Inc 25 June 1976 [14 July 1975] 26497/76 Heading C2C [Also in Divisions C3 and C5] Vinyl or vinylidene monomers, e.g. methyl methacrylate or vinyl acetate, are stabilized against polymerization by the addition of a polymerization inhibitor of the formula where R is H or C 1 -C 4 alkyl, R 1 , R 2 , R 3 and R 4 are C 1 -C 5 alkyl groups and R 5 , R 6 , R 7 and R 8 are H or C 1 -C 5 alkyl provides not more than 2 of these latter are secondary or tertiary alkyl groups. The biphanols may be prepared by the oxidative coupling of an alkylphenol using (1) a catalyst comprising a copper compound, an anionic surfactant and an alkaline material (e.g. cupric acetate monohydrate, sodium lauryl sulphate and Na 2 CO 3 ) or (2) alkaline material (e.g. NaOH) and a pallodium catalyst or (3) a metal complex of an amino acid. Examples 1 to 6 describe the preparation of 3,3<SP>1</SP>,5,5<SP>1</SP>- tetramethyl - 4,4<SP>1</SP> - biphenol; 3,31 - dimethyl- 5,5<SP>1</SP> - di - t - butyl - 4,4<SP>1</SP> - biphenol; 3,3<SP>1</SP>,5,5<SP>1</SP>- tetrasec.butyl - 4,41 - biphenol; and 3,3<SP>1</SP>,5,5<SP>1</SP>- tetramethyl - 4,4<SP>1</SP> - biphenol mono methyl ether, the latter by reacting the biphenol with aqueous NaOH and methyl chloride. |
