Opt. heat-modified nitrile polymers, (I), are used as catalyst supports in organic isocyanate prepn. by liq. phase organic nitro cpd. reaction with CO in the presence of heterogeneous supported catalysts contg. 1 Gp. VIII precious metal cpd. and =1 Gp. V to VIII base metal cpd. High reaction temps. and pressures are used, pref. 150-250 degrees C and 5-500 bar. Organic monoisocyanates are intermediates for pesticide prodn. Organic polyisocyanates, esp. diisocyanates, are polyurethane raw materials. High prod. yields can be obtd. In an example, replacement of a kieselguhr support by a modified HCN polymer increased isocyanate yield from 38.1-92.8% of theoretical. The modified (I) have high heat-stability and fixing activity for the active precious metal component.
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