Preparation method of 2,4,6-toluene triisocyanate

Abstract

The invention provides a preparation method of 2,4,6-toluene triisocyanate, which comprises the steps of 1, under the catalytic action of nitrogen-doped porous carbon supported palladium, taking 2,4,6-trinitrotoluene as a raw material to obtain 2,4,6-triaminotoluene hydrochloride; and 2, taking 2,4,6-triaminotoluene hydrochloride as a raw material, and carrying out phosgenation reaction and reduced pressure distillation to prepare 2,4,6-toluene triisocyanate. The catalyst nitrogen-doped porous carbon loaded palladium adopted by the invention has the characteristics of simple preparation, low palladium loading capacity, efficient catalysis and reusability, and the production cost can be obviously reduced. Each step has the advantages of simple operation, high reaction conversion rate, easyseparation and collection of intermediate and final products, and the like. The preparation method has the advantage of low overall difficulty. Moreover, all intermediate products in the method are high in reaction activity, can be fully reacted, have few by-products, and are more beneficial to realizing high-quality production of 2,4,6-toluene triisocyanate.

Description

technical field [0001] The invention relates to the fields of chemical industry and materials, and mainly relates to a preparation method of 2,4,6-toluene triisocyanate. Background technique [0002] The homologue of 2,4,6-toluene triisocyanate (TTI), namely 2,4-toluene diisocyanate or 2,6-toluene diisocyanate, has been widely used in the synthesis of materials such as polyurea and polyurethane, and is very important Chemical intermediates. However, because most of the products exist in the form of mixtures, the analysis of the properties and structures of downstream products is greatly affected; if a pure single product is to be obtained, cumbersome purification processes are required and production costs are increased. However, the position of the substituent of 2,4,6-toluene triisocyanate (TTI) is determined, and there is no series of problems caused by the mixture of isomers in the product. In addition, the TTI molecule contains three isocyanate groups, which can be use...

AI Technical Summary

Problems solved by technology

[0004] At present, there are mainly three technical bottlenecks for TNT being converted into TTI: (1) the catalyst used in the preparation of triaminotoluene and its hydrochloride by catalytic hydrogenation of TNT is expensive and cannot be recycled, causing the economic cost of preparing the product to remain high. Find cheaper catalysts or low-load reusable high-efficiency catalysts to replace existing catalysts; (2) Part of the steps in the methods for preparing triaminotoluene and its hydrochloride by catalytic hydrogenation are harsh and difficult to implement, resulting in Triaminotoluene and its hydrochloride cannot be produced on a large scale; (3) the preparation and purification methods of TTI are limited, and there is a lack of methods for preparing and purifying trifunctional isocyanate solids

[0005] Considering that the catalysts currently used in the hydrogenation reduction reaction are expensive and difficult to reuse, the high value-added products of TNT are rare, and the preparation of TTI is difficult, and many problems arise from the synthesis and purification methods.

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