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Process for the continuous preparation of (cyclo) aliphatic diisocyanates

A diisocyanate and production method technology, applied in chemical instruments and methods, preparation of carbamate, preparation of carbamic acid derivatives, etc., can solve problems such as agglomeration cleaning process, unsatisfactory separation, unsatisfactory agglomeration, etc. , to achieve the effect of improving the economy

Inactive Publication Date: 2008-08-06
EVONIK DEGUSSA GMBH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0016] The by-products formed not only lead to undesired agglomeration in the plant after a short time during the continuous one- or multi-step synthesis of bisurethanes, as a result of which the production duration is shortened and thereafter Requires costly cleaning procedures and cannot be separated satisfactorily in the various distillation steps known and described in the literature for the purification of crude biscarbamate
[0017] In plants for the thermal decomposition of (cyclo)aliphatic bisurethanes to (cyclo)aliphatic diisocyanates, the by-products from the bisurethane stage itself that cannot be quantitatively removed and the resulting new A series of by-products can additionally cause caking and thus reduce the performance of the equipment due to expensive cleaning procedures

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0123] The steam-heated preheater is pumped into the first tray of the distillation reactor by 41.0kg 5-amino-1,3,3-trimethylcyclohexanemethylamine per hour, 29.8kg untreated urea and 107.0 kg of n-butanol, the reaction mixture is continuously separated from the released ammonia under normal pressure.

[0124] The average residence time in the distillation reactor was 7 h. 12.5 kg / h of butanol from the bottom of the ammonia-butanol separation column were fed to the bottom of the distillation reactor operated at atmospheric pressure. The energy input to the distillation reactor through the reboiler is determined by the following method, that is, the amount of butanol that reaches the top of the tower together with the generated ammonia and is condensed with warm water at 40 ° C in the fractionation tower is the same as the amount of butanol that is sent to the bottom of the tower. The amount of alcohol is equivalent. The alcohol thus condensed is fed continuously to the ammon...

Embodiment 2

[0136] Through the steam-heated preheater pumped into the first-stage tray of the pressurized distillation reactor per hour by 38.4kg 5-amino-1,3,3-trimethylcyclohexanemethanamine, 27.9kg without Treat urea, a mixture consisting of 100.1 kg of n-butanol and 57.4 kg of the reaction product from the reurethanization step, which mixture is heated to 190-200°C in a preheater.

[0137] The average residence time in the heated distillation reactor was 10.5 h. The following temperature profile is established by heating: 230°C at the bottom and 200°C at the top. Add 96.7kg / h butanol to the bottom of the column of the pressurized distillation reactor, and the amount of heat-carrying oil introduced into the reboiler is established in the following manner, that is, the amount of butanol that flows out together with the ammonia generated at the top of the column is the same as that added to the column. The amount of the bottom is equivalent.

[0138] The resulting butanol / ammonia mixtur...

Embodiment 3

[0148] Via the steam-heated preheater, the first-stage tray of the pressurized distillation reactor is pumped into 34.7kg (2,2,4-)2,4,4-trimethylhexamethylenediamine per hour , 27.2kg of untreated urea, a mixture of 97.8kg of n-butanol and 64.0kg of the reaction product of the reurethanation step, which is heated to 190-200°C in a preheater.

[0149] The average residence time in the pressure distillation reactor was 10.5 h. The following temperature profile was established by heating: 228°C at the bottom and 200°C at the top. Add 94.3kg / h butanol to the bottom of the tower of the pressurized distillation reactor, and the amount of heat transfer oil is determined in the following manner, that is, the amount of butanol flowing out together with the ammonia generated at the top of the tower is equivalent to the amount that is added to the bottom of the tower.

[0150] The resulting butanol / ammonia mixture is then fed to an ammonia-butanol separation column. Its top temperature...

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Abstract

The invention relates to a multi-stage process for the continuous, phosgene-free preparation of (cyclo)aliphatic diisocyanates that comprises the conversion of (cyclo)aliphatic diamines into the corresponding (cyclo)alkylene biscarbamates and the thermal cleaving of the latter into the (cyclo)alkylene diisocyanates and alcohol. The urea used in accordance with the invention and also the urea employed for the preparation of urea equivalents (e.g. alkyl carbonates, alkyl carbamates) as a possible precursor for the synthesis of the (cyclo)aliphatic biscarbamates is unconditioned.

Description

technical field [0001] The present invention relates to a kind of non-carbonyl chloride continuous multi-stage production method of aliphatic (cyclo) diisocyanate, the method comprises converting aliphatic (cyclo) diamine into corresponding (cyclo) alkylene biscarbamate and converting The latter thermally decomposes into (cyclo)aliphatic diisocyanates and alcohols. Background technique [0002] Diisocyanates are valuable chemical compounds that can form target polymer structures according to the principle of the diisocyanate polyaddition method. These polymers can be used in the form of polyurethane or polyurea in foams, elastomers, thermoplastics, fibers , in light-resistant polyurethane coatings or adhesives for a wide variety of industrial applications. [0003] The synthetic route to isocyanates can be achieved via a series of different routes. The earliest and still dominating large-scale industrial preparation of isocyanates was the phosgenation of the corresponding ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C265/14C07C263/04
CPCC07C269/04C07C263/04C07C2101/14C07C2601/14C07C271/12C07C271/24C07C265/14
Inventor H·-W·米查尔扎克S·科尔斯特鲁克M·克勒辛斯基G·格伦德R·洛莫尔德
Owner EVONIK DEGUSSA GMBH
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