Preparing method of toluene diisocynate

The invention relates to a preparing method of toluene diisocynate. The method includes the steps of adding a catalyst (polyoxometallate) and a solvent into a reaction container, then adding the raw material (2,6-diaminotoluene), phenylsilane, an acid-binding agent and a dehydrating agent to be evenly mixed, finally adding gas-state carbon dioxide, and conducting magnetic stirring and sufficient reacting at a certain temperature to obtain a product. In the method, Anderson type heteropolyacid serves as the catalyst, the catalyst requires mild reaction conditions and is high in specific selectivity, recyclable and friendly to the environment, the industrial reaction cleanliness is improved, the process economy is improved, manufacturing cost and three wastes are reduced, environmental protection pressure is relieved, and industrial production is facilitated. 本发明涉及一种甲苯二异氰酸酯的制备方法，将催化剂多金属氧酸盐、溶剂加入反应容器，再加入原料2,6-二氨基甲苯以及苯硅烷、缚酸剂和脱水剂，一同混合均匀，最后加入气态二氧化碳，一定温度下磁力搅拌充分反应，即得到产物。本发明方法采用Anderson型杂多酸作为催化剂，该催化剂所需反应条件温和、专一选择性高，可回收