Process for preparing isocyanate by phosgenation reaction

A technology of isocyanate and phosgenation, which is applied in the preparation of isocyanic acid derivatives, organic compounds, organic carbonates, etc., to achieve the effect of saving system energy consumption and fully utilizing the value of materials

Inactive Publication Date: 2021-07-13
新沂市永诚化工有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, so far, the non-phosgenation isocyanate production technology is still difficult to compete with the phosgenation method in the short term in terms of economic benefits and technical maturity. Therefore, further research on the phosgenation isocyanate production technology has potential. important practical significance

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] A kind of technology that adopts phosgenation reaction to prepare isocyanate, described processing step is:

[0025] Step 1, mixing and stirring bis(trichloromethyl)carbonate and toluene solution or ethylene dichloride solution in a preparation kettle to obtain trichloromethyl chloroformate;

[0026] Step 2: Add hydrochloric acid dropwise to the 1,6-diaminohexane solution, start heating the solution when the pH of the amine solution is <2, and at the same time separate the water in the amine solution through the reflux condenser until it reaches the water separator no bead formation;

[0027] Step 3, splitting 20% ​​of the amine solution after removing water in step 2 and trichloromethyl chloroformate obtained in step 1 are respectively heated and gasified into a gas phase state in a gasifier;

[0028] Step 4. Put the gas-phase amine solution and liquid amine solution obtained in step 3 together into a reactor equipped with gas-phase trichloromethyl chloroformate at a ...

Embodiment 2

[0033] A kind of technology that adopts phosgenation reaction to prepare isocyanate, described processing step is:

[0034] Step 1, mixing and stirring bis(trichloromethyl)carbonate and toluene solution or ethylene dichloride solution in a preparation kettle to obtain trichloromethyl chloroformate;

[0035] Step 2: Add hydrochloric acid dropwise to the 1,5-diaminopentane solution, start heating the solution when the pH of the amine solution is <2, and at the same time separate the water in the amine solution through the reflux condenser until it reaches the water separator no bead formation;

[0036] Step 3, splitting 50% of the amine solution after removing water in step 2 and trichloromethyl chloroformate obtained in step 1 are respectively heated and gasified in a gasifier to form a gas phase state;

[0037] Step 4. Put the gas-phase amine solution and liquid amine solution obtained in step 3 together into a reactor equipped with gas-phase trichloromethyl chloroformate at ...

Embodiment 3

[0042] A kind of technology that adopts phosgenation reaction to prepare isocyanate, described processing step is:

[0043] Step 1, mixing and stirring bis(trichloromethyl)carbonate and toluene solution or ethylene dichloride solution in a preparation kettle to obtain trichloromethyl chloroformate;

[0044] Step 2. Add hydrochloric acid dropwise to the 1,3-bis(aminomethyl)cyclohexane solution, and start heating the solution when the pH of the amine solution is less than 2, and simultaneously separate the water in the amine solution through a reflux condenser, Until no water drops are formed in the water separator;

[0045] Step 3, splitting 80% of the amine solution after removing water in step 2 and trichloromethyl chloroformate obtained in step 1 are respectively heated and gasified into a gas phase state in a gasifier;

[0046] Step 4. Put the gas-phase amine solution and liquid amine solution obtained in step 3 together into a reactor equipped with gas-phase trichlorometh...

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PUM

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Abstract

The invention relates to the field of preparation methods of isocyanate, and concretely relates to a process for preparing isocyanate by phosgenation reaction. The process comprises the following steps: mixing and stirring di(trichloromethyl) carbonate and a solvent in a preparation kettle to obtain trichloromethyl chloroformate; dropwise adding hydrochloric acid into the amine solution, heating, and condensing to remove water; mixing the amine solution and trichloromethyl chloroformate in a reactor to obtain crude isocyanate; introducing inert gas into the reactor, discharging hydrogen chloride generated by reaction from the reactor into a tail gas collecting box, and treating gas in the tail gas collecting box; and purifying the crude isocyanate through a distillation tower to obtain the isocyanate product. The preparation process adopted by the invention is more environment-friendly and safer, and can bring higher economic benefits.

Description

technical field [0001] The invention relates to the field of isocyanate preparation methods, in particular to a process for preparing isocyanate by phosgenation reaction. Background technique [0002] As an important chemical intermediate, isocyanate is widely used in the fields of polyurethane, coatings, dyes, thermal insulation materials and medicine, and has broad market prospects. Phosgenation reaction technology is currently the most important method for preparing isocyanate. In industrial production facilities, only a very small amount of isocyanate is produced by non-phosgenation method. The phosgenation reaction generally refers to a reaction involving phosgene as a reactant. For organic isocyanates, the specific reaction process can be divided into two stages: in the first stage, organic amine and phosgene react to produce acid chloride and hydrogen chloride, and the hydrogen chloride released from the reaction may combine with the amine group of the reactant to fo...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C263/10C07C265/14
CPCC07C263/10C07C68/06C07C2601/14C07C265/14C07C69/96
Inventor 徐西之巩绪干
Owner 新沂市永诚化工有限公司
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