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Preparation method of 1-bromo-1-chloro-2,2-difluoroethylene

A technology of difluoroethylene and difluoroethane, which is applied in the field of preparation of fluorine-containing organic intermediates, can solve problems such as waste of resources, and achieve the effects of fast reaction speed, environmental friendliness, and high yield

Active Publication Date: 2015-12-16
HUNAN CITY UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, while producing 10,000 tons of trifluorodichloroethane per year, only about 200 tons of difluorotrichloroethane (R122) (the amount of the mixture containing R122) is produced each year, and the incineration treatment method causes great waste of resources

Method used

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  • Preparation method of 1-bromo-1-chloro-2,2-difluoroethylene

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preparation example Construction

[0060] A preparation method of 1-bromo-1-chloro-2,2-difluoroethylene, which comprises the following steps:

[0061] (1) In an inert solvent, difluorotrichloroethane is used as raw material to carry out reductive dechlorination reaction with zinc powder to obtain 2-chloro-1,1-difluoroethylene;

[0062] The inert solvent of the present invention is one or a combination of alcohol solvents or amide solvents or ether solvents or acid anhydride solvents or oxygen-nitrogen-containing compound solvents or sulfur-containing compound solvents; The volume ratio of ethyl chloride is 1-10:1;

[0063] The volume ratio of the inert solvent in the present invention to difluorotrichloroethane is preferably 2-5:1;

[0064] In step (1) of the present invention, the alcohol solvent includes one or a combination of methanol, ethanol, propanol, butanol, ethylene glycol, glycerin; the amide solvent includes N,N-dimethylformaldehyde One or a combination of amides, N,N-dimethylacetamide; the ether ...

Embodiment 1

[0102] Zinc powder pretreatment:

[0103] Stir 2.4㎏ zinc powder with 6L 2% hydrochloric acid for 2 hours, filter to remove the acid, put the zinc powder in a 10L plastic beaker, wash once with 6L 2% hydrochloric acid, then wash three times with distilled water (5L each time), and then Wash twice with 95% ethanol (3L each time), and finally wash once with 3L anhydrous ether. Filter after each wash to remove washes. The treated zinc powder is thoroughly dried under the protection of nitrogen, and the lumps are ground in a mortar. The treated zinc powder is used under the protection of nitrogen.

[0104] Preparation of R12212:

[0105] A two-stage reflux condenser is connected to a 5-liter there-necked bottle equipped with a mechanical stirrer and a constant-pressure dropping funnel, wherein the first-stage reflux condenser is cooled by tap water, and the second-stage reflux condenser is condensed by circulating alcohol in a refrigerator. Control the temperature of the alcoho...

Embodiment 2

[0117] Preparation of R12212:

[0118] Install a 5-liter three-necked flask with a reflux condenser, a mechanical stirring device, and a constant-pressure dropping funnel, and add 2 liters of 1,4-dioxane (China Wulian Chemical Factory), activated zinc 325 grams of powder (analytically pure, Shanghai Shenxiang Chemical Reagent Co., Ltd.) and 11 grams of elemental iodine were reacted at 100 ° C, and 580 g of difluorotrichloroethane (R122, GC purity greater than 95%, Sinochem Lantian Group Co., Ltd. produces by-products of R123), and continued to react for 4 hours, and the generated R1122 was introduced into the second reaction bottle, and 60ml of solvent acetic acid and 493 grams of bromine were added to the second reaction bottle, and the reaction temperature was 40±5°C , and stir the reaction until the red color (bromine) of the reaction solution disappears, first wash three times with 300ml of water, and then the organic phase is distilled under reduced pressure with a water ...

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Abstract

The invention discloses a method for preparing 1-bromo-1-chloro-2,2-difluoroethylene from waste difluorotrichloroethane (R122) generated in a trifluorodichloroethane production process, which comprises the following step: carrying out reduction dechlorination reaction, bromine addition reaction and hydrogen bromide removal reaction. By using the R123 production waste difluorotrichloroethane to produce the high-added-value fluorine-containing intermediate R111211, the raw material cost is low. Meanwhile, the method implements recovery and reutilization on the solvent and catalyst, and reduces the environmental pollution. The method has the advantages of high operability, mild reaction, high reaction speed, high yield, high selectivity, environment friendliness and the like, and can be used for industrial production.

Description

technical field [0001] The present invention relates to the preparation of a fluorine-containing organic intermediate, in particular to a preparation method of 1-bromo-1-chloro-2,2-difluoroethylene, in particular to a method using difluorotrichloroethane Process for producing 1-bromo-1-chloro-2,2-difluoroethylene. Background technique [0002] 1-Bromo-1-chloro-2,2-difluoroethylene (R111211) is an important fluorine fine chemical raw material. Because the molecule contains double bonds, bromine atoms, and chlorine atoms, it can be synthesized by organic reactions containing difluorine Group series of compounds. R111211 is an important difluoro group building block molecule. R111211 is mainly used in the synthesis of some fluorine-containing pharmaceuticals and pesticide intermediates. At present, the application of R111211 at home and abroad is still under development, and many new products are still under continuous development. Therefore, R111211 has great development pro...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C21/18C07C17/25
Inventor 钟桐生康茹茹周升华严妍向绍基
Owner HUNAN CITY UNIV
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