| 摘要 |
1458595 Isocyanate preparation ATLANTIC RICHFIELD CO 3 May 1974 [4 May 1973 8 March 1973] 19578/74 Heading C2C Isocyanates are prepared by thermally decomposing an ester of a carbamic acid having the formula R(NHCOOR<SP>1</SP>) x or (RNHCOO) x R<SP>1</SP> wherein each R is an optionally substituted mono-, di- or tri-valent organic radical selected from saturated and monoolefinic unsaturated straight and branched chain aliphatic and cyclealiphatic radicals of not more than 32 carbon atoms, alkoxyalkyl radicals of not more than 32 carbon atoms, and aryl, aralkyl and alkaryl radicals having 1 to 5 rings; each R<SP>1</SP> is an optionally substituted mono-, di- or tri-valent organic radical selected from saturated and monoolefinic unsaturated straight and branched chain aliphatic and cycloaliphatic radicals of not more than 32 carbon atoms, alkoxy-alkyl radicals of not more than 32 carbon atoms, and aryl, aralkyl and alkaryl radicals containing 1 to 3 rings; and x is 1, 2 or 3; at from 175‹ to 350‹ C. while said ester is dissolved in an inert solvent to produce an isocyanate and an alcohol, the solvent being a compound or mixture of compounds which is (a) a solvent for said ester, (b) liquid and stable at the decomposition temperature and (c) nonreactive with isocyanate product, and selected from optionally halo- and mono-nitro-substituted C 4 to C 32 aliphatic hydrocarbons, cycloaliphatic hydrocarbons, aromatic hydrocarbons having 1 to 3 rings, (C 1 to C 15 alkyl)benzenes, halo- and mono-nitro-derivatives of the aromatic hydrocarbons and alkylbenzenes, and C 4 to C 32 ethers, ketones and carboxylic esters and their sulphur analogues. |
