| 摘要 |
1,197,437. Stabilizing isocyanates. IMPERIAL CHEMICAL INDUSTRIES Ltd. 15 Sept., 1967 [23 Sept., 1966], No. 42621/66. Heading C2C. Organic isocyanates are stabilized by distilling in presence of an organic free-radical capture agent (i.e. a compound reacting with a free-radical to give a more stable free-radical) other than guiacol. Specified isocyanates are phenyl, alpha-naphthyl, octadecyl, chlorophenyl (o-, m-, p-), butyl and cyclohexyl isocyanates; hexamethylene, phenylene, tolylene (2,4- and 2,6), diphenylmethane (4,4<SP>1</SP>), chlorophenylene (2,4), naphthylene (1,5), diphenylene (4,4<SP>1</SP>), 3,3<SP>1</SP>-dimethyldiphenylene (4,4<SP>1</SP>), 3-methyldiphenylmethane (4,4<SP>1</SP>), diphenyl ether, cyclohexane (1,4- and 1,3-), 1-methylcyclohexane (2,4- and 2,6) and methylene bis-(cyclohexyl) diisocyanates; toluene (2,4,6-) and diphenyl ether (2,4,4<SP>1</SP>) triisocyanates. Specified freeradical capture agents are 2,4-dimethyl-6- (alpha-methylcyclohexyl) phenol, 4-tertiarybutylcatechol, propyl gallate, diphenylamine, 4- isopropylaminodiphenylamine, phenothiazine, 2,2,6,6 - tetramethylpiperid - 4 - ore, 1,1- diphenyl - 2 - (2<SP>1</SP>,4<SP>1</SP>,6<SP>1</SP>- trinitrophenyl)- hydrazine, 9,10-dihydroanthracene, 9,9<SP>1</SP>-bis- (fluorenylidene), omega-[4<SP>1</SP>-hydroxy-3<SP>1</SP>,3<SP>1</SP>-di. (tert-butyl) phenyl]-2,6-di-(tert-butyl)-benzoquinone - 4 - methide, 9,91 - bis - (anthronylidene), 9,9<SP>1</SP> - bis - (anthronylidene)ethane, thiocarbanilide, bis - (2 - benzthiazolyl) disulphide, benzthiazolyl - 2 - cyclohexylsulphenamide, bis - (2 - benzimideazolyl) - disulphide, zinc thiobenzoate aid zinc dimethyldithiocarbamate. Tolylene diisocyanate stabilized in this manner may be catalytically trimerized (in ester solvent using metal salt+ phenol) more rapidly than unstabilized starting material, giving the isocyanurate. |
