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A kind of equipment and method for preparing isocyanate by pressurized pyrolysis

An isocyanate and equipment technology, applied in the field of isocyanate preparation, can solve the problems of difficulty in product concentration and separation, complex process routes, environmental pollution, etc., and achieve the effects of reducing the possibility of side reactions, cheap and easy-to-obtain solvents, and shortening reaction time.

Active Publication Date: 2016-06-22
INST OF PROCESS ENG CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The technical solution of the present invention: to overcome the problems of serious environmental pollution, complex process route, and difficulty in product concentration and separation in the prior art, provide a kind of equipment and method for preparing isocyanate by pressurized pyrolysis, improve the conversion rate and yield of reaction, and at the same time It can better realize product separation, is easy to integrate with existing industrial technology, and can realize recycling, which is environmentally friendly and pollution-free

Method used

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  • A kind of equipment and method for preparing isocyanate by pressurized pyrolysis

Examples

Experimental program
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Effect test

Embodiment 1

[0029] Weigh 160g of phenylcarbamate and 3L of chlorobenzene into the pyrolysis reactor, seal the reactor, replace the air with nitrogen for 3 times, heat up to 240°C and 1.5MPa, fill the rectification tower with structured packing, and The temperature is 160-220°C. During the reaction, argon gas is continuously fed into the reaction kettle 2 through the inert gas purge port 10, and the low-carbon alcohol gas generated by the reaction enters the precision reactor through the gas rising pipeline 4 along with the argon gas and the vaporized chlorobenzene solvent. In the distillation column 3, the solvent and low-carbon alcohol are separated in the rectification column 3, chlorobenzene is refluxed from the liquid return port 5 of the tower body to the reaction kettle 2, and the argon and low-carbon alcohol are discharged through the condenser 6 and the gas discharge port 8 . The reaction is kept for 1 hour. After the reaction, the product is separated by the falling film evaporat...

Embodiment 2

[0032] Weigh 3000g of phenylcarbamate and add 0.5L of nitrobenzene into the pyrolysis reactor, seal the reactor, replace the air with nitrogen for 3 times, then heat up to 190°C and 0.4MPa, and the rectification tower is packed neatly Packing, the temperature of the tower is 110-170°C, during the reaction process, argon gas is continuously fed into the reaction kettle 2 through the inert gas purge port 10, and the low-carbon alcohol gas generated by the reaction passes through the gas riser along with the argon gas and the vaporized nitrobenzene solvent Road 4 enters the rectifying column 3, and the solvent and lower-carbon alcohol are separated in the rectifying column 3, and nitrobenzene flows back into the reaction kettle 2 from the tower body liquid return port 5, and argon and lower-carbon alcohol pass through the condenser 6 and The gas discharge port 8 is discharged. The reaction is maintained for 8 hours. After the reaction is completed, the product is separated by the...

Embodiment 3

[0035] Weigh 500g of diphenylmethane dicarbamate and 3L of o-dichlorobenzene into the pyrolysis reactor, seal the reactor, replace the air with nitrogen for 3 times, heat up to 250°C and 1.7MPa, Filled with structured packing, the temperature of the tower is 170-230°C, during the reaction process, nitrogen gas is continuously passed into the reactor 2 through the inert gas purge port 10, and the low-carbon alcohol gas generated by the reaction rises with the nitrogen gas and the vaporized o-dichlorobenzene solvent through the gas The pipeline 4 enters the rectification column 3, and the solvent and low-carbon alcohol are separated in the rectification column 3, and o-dichlorobenzene flows back into the reactor 2 from the liquid return port 5 of the tower body, and nitrogen and low-carbon alcohol pass through the condenser 6 And the gas outlet 8 is discharged. The reaction is maintained for 3 hours. After the reaction is completed, the product is separated by the falling film e...

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Abstract

The invention relates to equipment and a method for preparing isocyanate through compression pyrolysis, and belongs to the technical field of preparation of isocyanate through pyrolysis. The reactor is an integrated reactor of a high pressure pyrolytic reaction kettle and a rectifying tower and comprises a pyrolytic reaction kettle and a rectifying tower; a gas rising pipeline and a liquid return pipeline are connected between the pyrolytic reaction kettle and the rectifying tower; a condenser is arranged on the upper part of the rectifying tower; liquid in the condenser can reflow by inner circulation or outer circulation; a gas outlet is arranged on the upper part for connecting a pressure adjusting system to keep the pressure of the system; and the pyrolytic reaction kettle is simultaneously connected with a liquid phase output discharge processing system. Under the compression pyrolysis condition, solvent can be effectively separated from lower alcohol generated from reaction in the reaction process through separation of the rectifying tower, so that the reaction rate is improved, and the yield of isocyanate is enhanced.

Description

technical field [0001] The invention belongs to the technical field of isocyanate preparation, in particular to a device and method for preparing isocyanate by pressurized liquid phase pyrolysis of carbamate. Background technique [0002] Isocyanate is the main raw material for the production of polyurethane and is widely used in industries such as elastomers, coatings, plastics, pesticides and leather. At present, the domestic demand for isocyanate is increasing year by year, and a large amount of isocyanate is imported from abroad every year to meet the demand, so the application prospect of isocyanate is very broad. The isocyanate products on the market mainly include phenyl isocyanate (PI), diphenylmethane diisocyanate (MDI), toluene diisocyanate (TDI) and hexamethylene diisocyanate (HDI). [0003] At present, the production method of isocyanate at home and abroad is mainly the phosgene method. This method uses highly toxic phosgene as a raw material, and a large amount...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C263/04C07C265/14C07C265/12
Inventor 李会泉朱干宇陈家强王晨晔林滨曹妍王利国柳海涛
Owner INST OF PROCESS ENG CHINESE ACAD OF SCI
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