Process for preparing butyl isocyanate

A technology of butyl isocyanate and n-butylamine, which is applied in the field of synthesis of organic compounds, can solve the problems of no industrial value, large amount of bromine, and low product content, so as to reduce the occurrence of side reactions, increase conversion rate, and improve product conversion rate effect

Active Publication Date: 2006-10-11
JIANGSU ANPON ELECTROCHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The traditional process is to add n-butylamine and o-dichlorobenzene into the reactor, pass dry hydrogen chloride gas under stirring until saturated, then pass excess phosgene at 110-160°C, and then pass phosgene into the solution until the solution becomes clear After 20-30 minutes, pass through, collect the fraction before 160°C by distillation, then collect the fraction at 106-120°C by distillation, add anhydrous sodium carbonate to stand still, and filter to obtain butyl isocyanate. This method has low product content and low yield. Generally not more than 80%
In addition, it has been reported in the literature that the target product can also be obtained by reacting bromobutane and potassium cyanate in an organic solvent (dimethylformamide), but the amount of bromine used in the process is large and does not have industrial value

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] Example 1: In a 500L reactor, add 200 kg of xylene, pass 30 kg of phosgene through the phosgene introduction tube, and slowly add 14.6 kg of n-butylamine dropwise at 10°C. After 2 hours of dripping, then Stir the reaction for 1.5 hours, raise the temperature at a heating rate of 20°C / h to a state of reflux, and then slowly add 10 kg of phosgene until the material is in a clear and transparent state, stop passing through the phosgene, and after 1 hour of reaction, drive the phosgene with nitrogen for 1 hour. Weighed and analyzed the ester content in the phosgenation reaction solution, and the calculated reaction yield was 96.6%. The product was rectified to obtain a pure product with a product purity of 99.3%. The total yield of butyl isocyanate was 95.5% based on n-butylamine.

Embodiment 2

[0028] Example 2: In a 500L reactor, add 200 kg of xylene, pass 20 kg of phosgene through the phosgene introduction tube, and slowly add 14.6 kg of n-butylamine dropwise at 0°C. After 2 hours of dripping, then Stir the reaction for 3 hours, raise the temperature to a reflux state at a heating rate of 20°C / h, then slowly add 20 kg of phosgene until the material is in a clear and transparent state, stop passing through the phosgene, and after 1 hour of reaction, drive the phosgene with nitrogen for 1 hour. Weigh and analyze the ester content in the phosgenation reaction solution, and the calculated reaction yield is 97.0%. The product was rectified to obtain a pure product with a product purity of 99.0%. The total yield of butyl isocyanate was 95.8% based on n-butylamine.

Embodiment 3

[0029] Example 3: In a 500L reaction kettle, add 200 kg of xylene, pass 20 kg of phosgene through the phosgene introduction tube, and slowly add 14.6 kg of n-butylamine dropwise at 30°C. After 2 hours of dripping, then Stir the reaction for 1.5 hours, raise the temperature at a heating rate of 20°C / h to a state of reflux, and then slowly add 10 kg of phosgene until the material is in a clear and transparent state, stop passing through the phosgene, and after 1 hour of reaction, drive the phosgene with nitrogen for 1 hour. Weigh and analyze the ester content in the phosgenation reaction liquid, and the calculated reaction yield is 94.6%. The product was rectified to obtain a pure product with a product purity of 99.1%. The total yield of butyl isocyanate was 93.5% based on n-butylamine.

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PUM

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Abstract

The invention discloses a Method for preparation of butylisocyanate, using n-butylamine as raw materal, dimethylbenzene as dissolvant, reacting with excess carbonyl chloride, getting the product which the purity is higher than 99% after two steps photo aerification reaction of low-temperature, high-temperature and distillation. Adopting two steps photo aerification reaction of low-temperature, high-temperature can reduce occurrence of secondary reaction effectly. In n-butylamine terms, the total yield of this invention is more than 95%.

Description

1. Technical field [0001] The invention relates to a method for synthesizing organic compounds, in particular to a method for preparing butyl isocyanate. 2. Background technology [0002] Isocyanate is an important intermediate in organic synthesis. It can undergo nucleophilic addition reaction, participate in the cycloaddition of unsaturated systems, perform Diels-Alder reaction, or add to bifunctional compounds to form heterocyclic derivatives. This type of compound is widely used in the synthesis of pesticides and drugs. [0003] Butyl isocyanate is a colorless transparent liquid with strong irritation. It is an important organic intermediate and can be used in pharmaceutical and pesticide intermediates. The traditional process is to add n-butylamine and o-dichlorobenzene into the reactor, pass dry hydrogen chloride gas under stirring until saturated, then pass excess phosgene at 110-160°C, and then pass phosgene into the solution until the solution becomes clear After ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C263/10C07C265/04
Inventor 姜育田刘跃安礼如
Owner JIANGSU ANPON ELECTROCHEM
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