Preparation method of 4,4'-dicyclohexyl methane diisocyanate

The invention relates to a preparation method of 4,4'-dicyclohexyl methane diisocyanate. The method comprises the steps of firstly, adding a catalyst polyoxometallate and a solvent into a reaction vessel; then, adding a raw material of 4,4'-diamino dicyclohexyl methane, phenylsilane, an acid-binding agent and a dehydrating agent, and uniformly mixing the materials; finally, adding gaseous carbon dioxide and stirring the mixture for a thorough reaction through a magnetic force at a certain temperature to obtain a product. According to the method, M-Anderson type heteropoly acid is used as the catalyst, and the catalyst needs mild reaction conditions and is high in specific selectivity, recyclable and environmentally friendly; the cleanliness of an industrial reaction is improved, the economic efficiency of the process is improved, the manufacturing cost and the generation of three wastes are reduced, the environmental protection pressure is reduced, and industrial production is facilitated. 本发明涉及一种4,4'-二环己基甲烷二