Method for preparing isocyanate via reaction distillation method

A technology of isocyanate and reactive distillation, which is applied in the preparation of isocyanate derivatives, purification/separation of isocyanate derivatives, chemical instruments and methods, etc., can solve the problems of phosgene waste and large heat load, and achieve energy saving consumption, reduce heat load, and save energy

Inactive Publication Date: 2015-09-09
QINGDAO UNIV OF SCI & TECH +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Although this method has purified the phosgene discharged from the side line, the HCL gas separated from the top of the phosgene rectification tower will take away part of the phosgene, and this part of the gas will directly go to the HCL absorption system to cause waste of phosgene; If the amount of HCL gas is smaller, the temperature of the side line discharge of the photochemical reaction tower needs to be higher, resulting in a larger heat load in the reaction tower

Method used

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  • Method for preparing isocyanate via reaction distillation method

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Embodiment 1

[0016] In the phosgene purification tower overhead gas system of the present embodiment, the exhaust gas system directly removes 4934 kg of toluenediamine with a temperature of 100 ° C and a pressure of 22 bar in 14253 kg of DEIP (diethyl isophthalate) with a temperature of 90 ° C. Toluene diamine solution is formed; toluene diamine solution and 35115kg / h temperature is-10 ℃, the liquid phosgene of pressure is 22bar enters jet reactor 1 and carries out luminescence reaction to obtain luminescence material, and the temperature of luminescence material after reaction is 103°C, the pressure is 16bar; then transfer the luminescence material to the reactive distillation tower 2 to carry out the thermophotochemical reaction, the operating pressure of the reactive distillation tower 2 is 15.8bar, and the reactor of the reactive distillation tower 2 is formed by the reactive distillation tower The reboiler 2 is heated to 148°C, the thermal load of the reactor of the reactive distillati...

Embodiment 2

[0018]The phosgene refining tower and the reactive distillation tower in this embodiment form a coupling system, and 4934 kg of toluenediamine at a temperature of 100 °C and a pressure of 22 bar are dissolved in 14253 kg of DEIP (diethyl isophthalate) at a temperature of 90 °C , to form a toluene diamine solution; the toluene diamine solution and 35115 kg / h of liquid phosgene with a temperature of -10 ° C and a pressure of 22 bar enter the jet reactor 1 for a luminescence reaction to obtain a luminescence material, and the temperature of the luminescence material after the reaction The temperature is 103°C and the pressure is 16bar; then the luminescence material is transferred to the reactive distillation tower 2 for thermophotochemical reaction, the operating pressure of the reactive distillation tower 2 is 15.8bar, and the reactor of the reactive distillation tower 2 The tower reboiler 3 is heated to 148 ° C, the heat load of the tower kettle is 3352Kw, and the toluene diiso...

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Abstract

The invention belongs to the technical field of isocyanate preparation and relates to a method for preparing isocyanate via a reaction distillation method. The method includes that amine reacts with liquid phosgene to prepare the isocyanate, the amine and the liquid phosgene are in cold reaction in a jet reactor firstly prior to entering a reactive distillation column to be subjected to thermal reaction for preparing crude isocyanate, meanwhile excessive phosgene and a by-product HCL (hydrogen chloride) gas are separated by distillation, and the phosgene and the HCL gas are refined prior to recycling. The method is simple in technique, convenient to operate, capable of separating the by-product in time, energy saving, low in cost, high in efficiency and environment friendly.

Description

Technical field: [0001] The invention belongs to the technical field of isocyanate preparation, and relates to a method for preparing isocyanate by reactive distillation. The isocyanate is prepared by reacting amine and liquid phosgene. The amine and liquid phosgene are first cold-reacted in a jet reactor, and then enter reactive distillation. The tower undergoes thermal reaction to prepare crude isocyanate, while rectifying and separating excess phosgene and by-product HCL gas. Background technique: [0002] The high reactivity of the NCO functional group in organic isocyanate compounds makes them widely used as intermediates for the synthesis of fine chemical products such as pesticides and medicines and raw materials for the synthesis of polyurethane materials. At present, although a variety of methods for synthesizing organic isocyanates have been developed, so far, more than 90% of the world's organic isocyanate products, including MDI, TDI, HDI and other large-tonnage ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C263/20C07C265/14C07C263/10C01B31/28C01B7/07C01B32/80
CPCY02P20/10
Inventor 毕荣山谭心舜郑世清葛纪军曾民成韩传贵张波赵超
Owner QINGDAO UNIV OF SCI & TECH
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