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Multi-step method for continuously producing toluene diisocyanate

A technology of diisocyanate and cycloaliphatic diamine, which is applied in the direction of urea preparation, carbamate preparation, chemical instruments and methods, etc., and can solve redundant problems

Inactive Publication Date: 2008-06-25
GOLDSCHMIDT CHEM CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In the stage of distillative purification of diisocyanate, the additional equipment used to obtain the desired diisocyanate purity becomes superfluous

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment Construction

[0045] The process according to the invention allows cycloaliphatic diisocyanates to be produced without problems in very good yields under continuous operation. Particularly advantageous in the multistage process according to the invention is the fact that, when using cycloaliphatic diamines of the formula (II) as starting materials for the continuous synthesis of diisocyanates, it is also possible to largely avoid The sedimentation phenomenon caused by the nature of high-viscosity boiling material components can also ensure good equipment performance and good process yield for a long time. In addition, a further advantage of the multi-step process of the present invention is that it allows minimizing the amount of diurethane to be transferred into the vapor phase and thereby limiting the required energy consumption.

[0046] a) For the preparation of cycloalkylene diureas of formula (IV) in reaction step a), cycloaliphatic diamines of formula (II) and urea are present in the...

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Abstract

The present invention provides a multi-step method for continuously producing alicyclic vulcabond on the condition of non light and non-air, by the reaction of the alicyclic diamine and the carboxylic acid derivatives with alcohol producing alicyclic diurethane and subsequently decomposed into alicyclic vulcabond, characterized in that diurethane is formed by two steps, thermo-decomposing via removing diurethane of the easier boiler and the medium boiler to release desirable vulcabond, and continuously draining the product on the bottom of the part degradable tower of the degradable equipment, proceeding re-urethane by alcohol, then separating the high boiler, and then making the re-urethane product circle in the process, wherein using the unprocessed carbamide and / or carbamide equivalent made of un-precessed carbamide.

Description

technical field [0001] The invention relates to a multistage process for the continuous and phosgene-free preparation of cycloaliphatic diisocyanates. Background technique [0002] The synthetic route to isocyanates can be achieved via a series of different routes. The first, and still dominant, industrial-scale preparation of isocyanates is the so-called phosgene process. The basis of the method is the reaction of amines with phosgene. A disadvantage of the phosgene process is the use of phosgene, which, due to its toxicity and corrosiveness, places extremely high demands on operation on an industrial scale. [0003] There are also processes for preparing isocyanates on an industrial scale which bypass the use of phosgene. The term "phosgene-free process" is generally associated with the conversion of amines to isocyanates using alternative carbonylating agents such as urea or dialkyl carbonates (EP18586, EP355443, US4268683, EP990644). [0004] The urea route is based ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C265/14C07C263/06
CPCC07C265/14C07C2101/14C07C263/06C07C263/04C07C2601/14Y02P20/10
Inventor S·科尔斯特鲁克M·克雷克辛斯基H·-W·米查尔查克G·格伦德R·洛莫尔德
Owner GOLDSCHMIDT CHEM CORP
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