Preparation method of 2,4,6-toluene triisocyanate

A technology of toluene triisocyanate and trinitrotoluene, which is applied in the field of preparation of 2,4,6-toluene triisocyanate, can solve the problem of large-scale production of triaminotoluene and its hydrochloride, lack of preparation and purification of isocyanate solids , TTI preparation and purification methods are limited, etc., to achieve high-quality production, reduce preparation costs, and low prices

Active Publication Date: 2020-12-25
BEIJING INSTITUTE OF TECHNOLOGYGY
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  • Abstract
  • Description
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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...

Method used

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  • Preparation method of 2,4,6-toluene triisocyanate
  • Preparation method of 2,4,6-toluene triisocyanate
  • Preparation method of 2,4,6-toluene triisocyanate

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preparation example Construction

[0073] The catalyst nitrogen-doped porous carbon supported palladium used in the above preparation method is prepared by the following steps:

[0074] S21, step 1-1, using cyclohexanone shown in structural formula I and diaminomaleonitrile shown in structural formula II as raw materials, using a weak acid as a catalyst and solvent, and obtaining the hexacyanogen shown in structural formula III through the third reaction base pyrazine.

[0075] Specifically, using cyclohexanone shown in structural formula I and diaminomaleonitrile shown in structural formula II as raw materials, using acetic acid as a catalyst and solvent, the reaction temperature is 80°C to 140°C, and the reaction time is 1h to 10h Prepare the hexacyanopyrazine (HAT(CN) shown in structural formula III below 6 ).

[0076] S22, step 1-2, using the hexacyanopyrazine shown in the structural formula III as a raw material, through a cleavage reaction and a reduction reaction, to obtain the nitrogen-doped porous ca...

Embodiment approach

[0078] Strategy 1: using hexacyanopyrazine shown in structural formula III as a raw material, performing a cracking reaction to prepare nitrogen-doped porous carbon shown in structural formula IV; adding a palladium source and the nitrogen-doped porous carbon to the first solvent, performing a reaction to obtain palladium-supported nitrogen-doped porous carbon; the palladium-supported nitrogen-doped porous carbon undergoes a reduction reaction under the action of a first reducing agent to obtain the nitrogen-doped porous carbon-supported palladium.

[0079] Strategy 2: Add a palladium source and hexacyanopyrazine shown in structural formula III to the second solvent to react to obtain a mixture of palladium salt and hexacyanopyrazine shown in structural formula V; for the palladium salt and hexacyanopyrazine The mixture of hexacyanopyrazine is cleaved to obtain a cleavage product; the cleavage product undergoes a reduction reaction under the action of a second reducing agent to...

Embodiment 1

[0085] Step 1: HAT(CN) 6 Catalyst preparation.

[0086] Add cyclohexanone octahydrate (10g) and maleonitrile diamine (20g) into glacial acetic acid (400ml) and heat to reflux for 2h-3h, then filter while hot, and disperse the filter cake in about 30% nitric acid solution , heated at 80°C for 1h, washed with water, and dried to obtain brown solid HAT(CN) 6 (12g).

[0087] Step 2: Pd@C 2 Preparation of N catalyst.

[0088] The obtained tan solid HAT(CN) 6 (12g) was placed in a crucible, raised from room temperature to 700°C at a heating rate of 5°C / min, and kept at this temperature for 2 hours, and then lowered to room temperature at a cooling rate of 5°C / min to prepare a black sample C 2 N (10g).

[0089] Will C 2 N (10 g) and palladium acetate (0.2 g) were dispersed in deionized water (300 mL), sonicated for 10 min to disperse evenly, and excess sodium borohydride (1.0 g) aqueous solution was slowly added, and vigorously stirred for 60 min. Filtrate under reduced pres...

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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...

Claims

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Application Information

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IPC IPC(8): C07C263/10C07C265/14C07C209/36C07C211/54B01J27/24
CPCB01J27/24C07C209/36C07C263/10C07C265/14C07C211/54
Inventor 黄木华彭山青贾琼邓汉林罗贤升柴春鹏
Owner BEIJING INSTITUTE OF TECHNOLOGYGY
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