| 摘要 |
Isocyanates are prepared by reacting nitrocompounds with CO in presence of a catalyst system consisting of a noble metal and a Lewis acid, e.g. a halide of Fe, Al, Sn, Ti, Ga or Cu. Examples describe the preparation of phenyl isocyanate from nitrobenzene, 2-methyl-5nitrophenyl isocyanate (I) and 3-nitro-4-methyl isocyanate from 2,4-dinitrotoluene and 2,4-tolylenediisocyanate from I.ALSO:Catalysts for making isocyanates from CO and nitro-compounds consist of a noble metal and a Lewis acid, e.g. a halide of Fe, Al, Sn, Ti, Ga or Cu. In examples (A) 5% Pd-Al2O3 is treated with FeCl3 in ether, the latter evaporated and the catalyst dried by heating in a CO stream-it contains 3% Fe; (B) 5% Pd-BaSO4, 5% Pd-CaCO3, 5% Rh-Al2O3 and 5% Ru-Al2O3 are similarly impregnated with AlBr3, AlCl3 or FeCl3; (C) 5% Pt-C is similarly impregnated with FeCl3 to give 3% Fe. Catalyst systems are also formed in situ from (a) 5% Pd-C and FeCl3; (b) PdCl2 and Fe; (c) 5% Pd-C and Fe(CO)5; (d) 5% Pd-C and SnCl4; (e) Rh-C and AlBr3; (f) Rh-C and FeCl2; (g) Rh-C and AlCl3; (h) Pd-C and CuCl2; (i) Rh/C and HCl. |
