Synthesis process of 2-bromo-2, 2-difluoroacetonitrile

A technology of difluoroacetonitrile and synthesis process, which is applied in the field of chemistry, can solve problems such as being difficult to buy, and achieve the effect of low cost and simple process

Pending Publication Date: 2022-02-08
NANTONG BAOKAI CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The process uses highly toxic cuprous cyanide, and difluorodibromomethane is a

Method used

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Embodiment

[0019] A kind of synthesis technique of 2-bromo 2,2-difluoroacetonitrile, comprises the steps:

[0020] Step 1. First add ethyl difluorobromoacetate and solvent to the flask, control the temperature, feed ammonia gas until the reaction of ethyl difluorobromoacetate is complete, then the reaction solution is lowered to room temperature, and the solvent and the ethanol produced by the reaction are concentrated under reduced pressure , and vacuum-dry the precipitated solid to obtain difluorobromoacetamide; wherein, the solvent refers to one or more mixtures of methanol, ethanol, diethyl ether, methyl tert-butyl ether, methylene chloride, cyclohexane, and tetrahydrofuran. The volume ratio of ethyl difluorobromoacetate to solvent is 1:1-5. Control the temperature at 20-80°C when passing ammonia gas. When the solvent is concentrated under reduced pressure, the pressure is ≤2000pa.

[0021] Step 2, difluorobromoacetamide and phosphorus pentoxide are mixed in a certain proportion, p...

specific Embodiment 1

[0022] Specific embodiment 1. prepare difluorobromoacetamide

[0023] In a 1L flask, add 406g (2mol) ethyl difluorobromoacetate and 500ml anhydrous methanol respectively, heat up to 35°C, stir, and feed ammonia gas at a speed of 500ml / min, and detect ethyl difluorobromoacetate after 90min to react completely. Then the reaction solution was lowered to room temperature, concentrated by rotary evaporation to remove the solvent methanol and by-product ethanol, resulting in white crystals, which were then dried in a vacuum oven for 8 hours at a temperature of 25°C and a pressure of 1800pa. A total of 323.64 g of difluorobromoacetamide was obtained in the form of white crystals, with a yield of 93%.

specific Embodiment 2

[0024] Specific embodiment 2. prepare difluorobromoacetonitrile

[0025] Mix 323.64 g of difluorobromoacetamide and 800 g of phosphorus pentoxide obtained in the previous step, and then add it into a 2L flask. The product difluorobromoacetonitrile 264g was collected in the cold well, the content was 99.87%, and the yield was 91%.

[0026] Compared with other methods, the present invention avoids the use of highly toxic cuprous cyanide and difluorodibromomethane that damages the atmospheric environment. The raw materials are easy to obtain, the process is simple, and the cost is low. The yield can reach ≥ 85%, and the product purity ≥ 99.5% %.

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Abstract

The invention discloses a synthesis process of 2-bromo-2, 2-difluoroacetonitrile, which comprises the following steps of: 1, reacting ethyl difluorobromoacetate with ammonia gas to generate difluorobromoacetamide; and 2, dehydrating the difluorobromoacetamide under the action of phosphorus pentoxide to generate difluorobromoacetonitrile. The process is safe and reliable, the cost is low, the yield can reach more than or equal to 85%, and the product purity is more than or equal to 99.5%.

Description

technical field [0001] The invention belongs to the field of chemistry, and in particular relates to a synthesis process of 2-bromo-2,2-difluoroacetonitrile. Background technique [0002] Polyfluoroalkyl triazine is a new material with high thermal and chemical stability, and difluorobromoacetonitrile is an important intermediate for the synthesis of polyfluoroalkyl triazine. Patent CN201610793774.3 released a synthesis method of difluorobromoacetonitrile, which mainly reacts with difluorodibromomethane under the action of dibenzo-18-crown-6 as a catalyst in a mixed solvent of DMF and DME Difluorobromoacetonitrile is produced. The process uses highly toxic cuprous cyanide, and difluorodibromomethane is a substance that destroys the ozone layer, and it is difficult to buy in the market. Contents of the invention [0003] Purpose of the invention: In order to solve the deficiencies in the prior art, the invention provides a synthesis technique of 2-bromo-2,2-difluoroaceton...

Claims

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Application Information

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IPC IPC(8): C07C253/20C07C255/10
CPCC07C253/20C07C231/02C07C255/10C07C233/05
Inventor 葛繁龙王春雷王彬郭英杰黄凯华
Owner NANTONG BAOKAI CHEM
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