Synthesis method of m-xylylene diisocyanate (MXDI)

A technology of xylylene diisocyanate and synthetic method, which is applied to the preparation of isocyanic acid derivatives, purification/separation of isocyanic acid derivatives, chemical instruments and methods, etc., can solve the problems of increasing raw material costs, and achieve reduction The effect of production investment cost, equipment requirement reduction and strong market competitiveness

Inactive Publication Date: 2018-09-04
江阴市万丰化工物资有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This synthetic route avoids the use of phosgene, and reduces the requirement for the sealing of the reaction equipment to a certain extent, but it also uses salinated MXDA as a reactant, which requires the use of additional hydrochloric

Method used

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  • Synthesis method of m-xylylene diisocyanate (MXDI)
  • Synthesis method of m-xylylene diisocyanate (MXDI)

Examples

Experimental program
Comparison scheme
Effect test

Example Embodiment

[0035] Example 1

[0036] (1) Weigh 150g of solid phosgene and dissolve it in 300g of chlorobenzene to obtain the first solid phosgene solution, which is heated to 55°C for later use;

[0037] (2) Weigh 100g of metaxylylenediamine (MXDA) and dissolve it in 200g of chlorobenzene to obtain a metaxylylenediamine solution;

[0038] (3) The metaxylylenediamine solution of step (2) was added dropwise to the solution of the first solid phosgene of step (1) at 55° C. within 2 hours. During the dropping, the precipitate under stirring Gradually generated

[0039] (4) After the dropwise addition is completed, the temperature is increased to 80°C at a heating rate of 15°C / h and the reaction is kept for 2h, and then the temperature is raised to the reflux temperature within 2h, so that the reaction system is in a reflux state.

[0040] (5) Dissolve 100 g of solid phosgene in 500 g of chlorobenzene to obtain a second solid phosgene solution, and add the second solid phosgene solution to the reactio...

Example Embodiment

[0044] Example 2

[0045] (1) Weigh 150g of solid phosgene and dissolve it in an inert solvent consisting of chlorobenzene, dichlorobenzene and toluene with a total weight of 450g to obtain the first solid phosgene solution, which is heated to 60°C for use;

[0046] (2) Weigh 100g of metaxylylenediamine (MXDA) and dissolve it in 400g of said inert solvent to obtain a metaxylylenediamine solution;

[0047] (3) The metaxylylenediamine solution of step (2) was added dropwise to the solution of the first solid phosgene of step (1) at 60° C. within 2.5 hours. During the dripping process, precipitation was carried out under stirring. Things gradually formed;

[0048] (4) After the dropwise addition is completed, the temperature is increased to 90° C. at a heating rate of 17° C. / h and the reaction is kept for 2.5 hours, and then the temperature is raised to the reflux temperature within 2 hours, so that the reaction system is in a reflux state.

[0049] (5) Dissolve 100 g of solid phosgene in...

Example Embodiment

[0053] Example 3

[0054] (1) Weigh 150g of solid phosgene and dissolve it in an inert solvent composed of chlorobenzene, dichlorobenzene, toluene and xylene with a total weight of 750g, to obtain the first solid phosgene solution, and raise the temperature to 70°C for use;

[0055] (2) Weigh 100g of metaxylylenediamine (MXDA) and dissolve it in 500g of the inert solvent to obtain a metaxylylenediamine solution;

[0056] (3) Add the metaxylylenediamine solution of step (2) dropwise to the first solid phosgene solution of step (1) at 70°C within 3 hours. During the dropping process, the precipitate under stirring Gradually generated

[0057] (4) After the dropwise addition is completed, the temperature is raised to 100°C at a heating rate of 20°C / h and the reaction is kept for 3 hours, and then the temperature is raised to the reflux temperature within 2 hours, so that the reaction system is in a reflux state.

[0058] (5) Dissolve 100 g of solid phosgene in 1000 g of the inert solvent ...

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Abstract

The invention relates to the field of chemical products and chemical processes, in particular to an improved synthesis method of m-xylylene diisocyanate (MXDI). The method comprises the following steps: dropwise adding a m-xylylenediamine solution to a solid phosgene solution for reflux reaction, then dropwise adding another solid phosgene solution, performing continuous reaction under reflux state, cooling a product to room temperature, removing a solvent under reduced pressure, and rectifying to obtain MXDI. The method provided by the invention adopts direct solid light synthesis, and does not need to form salt, thereby reducing reaction steps and greatly lowering the production investment cost; with a clustering rectification manner, the equipment requirement is lowered by the increasedtower-to-tower diameter ratio, and no large rectifying tower is needed, so that the investment in utilities of steam, heat transfer oil and the like are extremely reduced while the production demandis satisfied. MXDI prepared by the method has the purity in 99.5% or higher, is colorless and transparent liquid, is high yield, and has strong market competitiveness.

Description

technical field [0001] The invention relates to the fields of chemical products and chemical technology, in particular to an improved synthesis method of m-xylylene diisocyanate. Background technique [0002] m-xylylene diisocyanate (MXDI) is an important class of aromatic polyisocyanate products, widely used in polyurethane industry. [0003] In the prior art, MXDI is generally prepared from m-xylylenediamine (MXDA) as a starting material, which is salted and then reacted with phosgene (JPH037253A). This synthetic route uses highly toxic phosgene, which requires good sealing of the reaction equipment, and the cost of staff protection and waste gas and waste liquid treatment has also led to an increase in the total cost; at the same time, due to the high cost of phosgene Therefore, the reaction controllability of this synthetic route is not good, the production process has high risk, and it is easy to cause the undesired polymerization of the product. [0004] In order to ...

Claims

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Application Information

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IPC IPC(8): C07C263/10C07C263/20C07C265/14
CPCC07C263/10C07C263/20C07C265/14
Inventor 王磊杨春华杨建良
Owner 江阴市万丰化工物资有限公司
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