Various allyl ethers were converted into the corresponding N-allylcarbamates usingchlorosulfonylisocyanate (CSI) via the stable allylic carbocation rather than β-lactam through [2+2] cycloaddition. The reaction of cinnamyl methyl ether with CSI afforded only methyl N-cinnamylcarbamate at 0°C, but at 20°C, it produced a mixture of methyl N-cinnamylcarbamate and methyl N-(1-phenylprop-2-enyl)carbamate
Process forthe production of alkyl isocyanates which can be defined by the general formula: R-N=C=O wherein R is an alkyl radical having from 1 to 4 carbon atoms by thermal decomposition of phenyl-N-alkyl urethans which can be defined by the general formula:
wherein R has the above defined meaning.
Said thermal decomposition is carried out without any substance having a catalytic activity being present in the decomposition reaction, by heating to a temperature of from 180°Cto 210°C underthe atmospherical pressure or a slightly reduced pressure, a mixture of phenol and phenyl-N-alkyl urethan, in a molar ratio of the former to the latter equal to or nearly equal to 1:1, removing by vaporization the phenol and the alkyl isocyanate from said vaporized products and maintaining in the reaction mixture, substantially throughout the thermal decomposition a molar ratio of phenol to phenyl-N-alkyl urethan not lower than about 1:1.
通过热分解苯基-N-烷基氨基甲酸酯(通式为:R-N=C=O,其中 R 为具有 1 至 4 个碳原子的烷基)生产烷基异氰酸酯的工艺:R-N=C=O 其中 R 为具有 1 至 4 个碳原子的烷基,通过热分解苯基-N-烷基氨基甲酸酯制得的烷基异氰酸酯,其通式可定义为
其中 R 具有上述定义的含义。
所述热分解是在分解反应中不存在任何具有催化活性的物质的情况下进行的,方法是在大气压或稍减压下,将苯酚和苯基-N-烷基脲的混合物加热到 180°C 至 210°C 的温度,前者与后者的摩尔比等于或接近等于 1:通过汽化从所述汽化产物中除去苯酚和异氰酸烷基酯,并在整个热分解过程中,在反应混合物中基本上保持苯酚与苯基-N-烷基脲的摩尔比不低于约 1:1。
LAURENT, A.;MISON, P.;NAFTI, ABDELHAFID;BEN, CHEIKH, RIDHA;CHAABOUNI, RIF+, J. CHEM. RES. MICROFICHE, 1984, N 11, 354-355