CN111233619A

CN111233619A - Method for synthesizing 4-halogenated-1, 1, 2-trifluoro-1-butene

Info

Publication number: CN111233619A
Application number: CN202010188745.0A
Authority: CN
Inventors: 刘庆彬; 冯官生; 王宝; 张福军
Original assignee: Hebei Normal University
Current assignee: Hebei Normal University
Priority date: 2020-03-17
Filing date: 2020-03-17
Publication date: 2020-06-05

Abstract

The invention discloses a method for synthesizing 4-halogenated-1, 1, 2-trifluoro-1-butene. The method specifically comprises the steps of synthesizing polyhalogenated ethane by the addition reaction of chlorotrifluoroethylene and halogen, then reacting the polyhalogenated ethane with ethylene under the action of a catalyst to synthesize polyhalogenated butane, and finally dehalogenating under the action of a reducing agent to synthesize the 4-halogeno-1, 1, 2-trifluoro-1-butene. The invention has the characteristics of simple synthesis method, high product purity and low preparation cost.

Description

Method for synthesizing 4-halogenated-1, 1, 2-trifluoro-1-butene

Technical Field

The invention relates to a method for synthesizing 4-halogenated-1, 1, 2-trifluoro-1-butene, belonging to the technical field of synthesis of pesticides and medical intermediates.

Background

Fluorine-containing olefin compounds are widely applied in the fields of pesticides and medicines, and CN1359379A, WO0102378 and US5952359 disclose the application of several 4-halogenated-1, 1, 2-trifluoro-1-butene in nematicidal pesticides. US2006/0052640 discloses a process for the preparation of 4-bromo-1, 1, 2-trifluoro-1-butene, but the raw materials used are not readily available and at the same time are costly and therefore would be desirable for further improvement.

Disclosure of Invention

The invention aims to provide a method for synthesizing 4-halogenated-1, 1, 2-trifluoro-1-butene, which overcomes the defects of the prior art.

The technical scheme adopted by the invention is as follows: a method for synthesizing 4-halo-1, 1, 2-trifluoro-1-butene comprising the steps of:

(1) preparation of polyhaloethanes

Putting 500ml of three-neck flask into a low-temperature bath, cooling to-50 ℃, adding halogen and a catalyst into the three-neck flask, stirring, introducing chlorotrifluoroethylene, controlling the temperature to be not higher than-40 ℃, obtaining yellowish liquid after the solution is faded after the reaction is finished, and directly carrying out the next reaction on polyhaloethane;

wherein, the halogen can be chlorine or liquid bromine or iodine, preferably chlorine, and the catalyst is benzophenone;

(2) preparation of polyhalogenated butanes

Adding polyhalogenated ethane and a catalyst into a high-pressure kettle, replacing ethylene for three times, controlling the ethylene pressure to be 1-2MPa, heating, starting a violent reaction in the kettle when the temperature is raised to 50 ℃, raising the temperature to 80-90 ℃, controlling the reaction temperature not to exceed 120 ℃, performing multiple punching, ensuring that the temperature is not obviously raised after gas is flushed, flushing 4MPa, reacting for 16 hours, and rectifying at normal pressure to obtain polyhalogenated ethane and polyhalogenated butane;

wherein the catalyst is one of azoisobutyronitrile, azodiisoheptonitrile, benzoyl peroxide, di-tert-butyl peroxide and dicumyl peroxide, preferably azoisobutyronitrile;

(3) preparation of 4-halo-1, 1, 2-trifluoro-1-butene

Adding a reducing agent into an alcohol solvent, heating to 50 ℃, dropwise adding polyhalogenated butane, reacting for 3h, controlling the temperature to be 50-90 ℃, continuing stirring for 30 minutes after the reaction is finished, and carrying out reduced pressure distillation to obtain the 4-halogenated-1, 1, 2-trifluoro-1-butene with the purity of 96%.

Wherein the reducing agent is iron powder or magnesium powder or zinc powder, preferably iron powder; the alcohol solvent is one of ethanol, n-butanol, isopropanol, ethylene glycol and diethylene glycol, preferably ethylene glycol.

The invention has the following beneficial effects: the method has the characteristics of easily obtained reaction raw materials, high yield, short steps, low cost and suitability for industrial production.

Detailed Description

The following examples serve to illustrate the invention.

EXAMPLE 1 preparation of polyhaloethanes

241g (3.4 mol) of liquid chlorine and 3.4g (0.02 mol) of benzophenone are added into a 500ml three-neck flask, cooled to-80 ℃, and introduced with chlorotrifluoroethylene until the solution fades, and the reaction is finished. Distillation under reduced pressure gave 584g of product in 92% yield and 98% purity GC. The yield was 94% when it was changed to bromine. The yield was 95% by iodine substitution.

EXAMPLE 2 preparation of polyhalogenated butanes

1125g of polyhalogenated ethane and 15g of azobisisobutyronitrile are added into a high-pressure kettle, ethylene is replaced for three times, then the pressure of ethylene is controlled at 1MPa, the temperature is raised to 50 ℃, the reaction in the kettle is violent, the exothermic temperature of the reaction is raised to 80-90 ℃, the pressure is 0MPa, the pressure is continuously stamped to 1MPa, the reaction temperature is controlled not to exceed 120 ℃, the multiple stamping is carried out, the temperature is not obviously raised after gas is flushed, the reaction is carried out overnight after the gas is flushed into the kettle, the polyhalogenated ethane is rectified under normal pressure to 480g, the polyhalogenated butane is 350g, the purity is 93%, and the yield is 77.

EXAMPLE 34 Synthesis of halo-1, 1, 2-trifluoro-1-butene

Adding 22.4g (0.4 mol) of iron powder into 200ml of ethylene glycol, heating to 50 ℃, dripping 90g of polyhalogenated butane, reacting for 3 hours, controlling the temperature to be 50-55 ℃, continuing stirring for 30 minutes after the reaction is finished, and carrying out reduced pressure distillation to obtain 51g of a product, wherein the purity is 96 percent and the yield is 90 percent by calculation.

Claims

1. A method for synthesizing 4-halo-1, 1, 2-trifluoro-1-butene, characterized by comprising the steps of:

(1) preparation of polyhaloethanes

wherein, the halogen is chlorine or liquid bromine or iodine, and the catalyst is benzophenone;

(2) preparation of polyhalogenated butanes

Adding polyhalogenated ethane and a catalyst into a high-pressure kettle, replacing ethylene for three times, controlling the ethylene pressure to be 1-2MPa, heating, starting a violent reaction in the kettle when the temperature is raised to 50 ℃, controlling the reaction temperature to be not more than 120 ℃, performing multiple stamping, reacting for 16 hours after the temperature is not obviously raised after gas is flushed, and rectifying at normal pressure to obtain polyhalogenated ethane and polyhalogenated butane;

wherein the catalyst is one of azoisobutyronitrile, azodiisoheptonitrile, benzoyl peroxide, di-tert-butyl peroxide and dicumyl peroxide;

(3) synthesis of 4-halo-1, 1, 2-trifluoro-1-butene

Adding a reducing agent into an alcohol solvent, heating to 50 ℃, dropwise adding polyhalogenated butane, reacting for 3 hours, controlling the temperature to be 50-90 ℃, continuing stirring for 30 minutes after the reaction is finished, and carrying out reduced pressure distillation to obtain 4-halo-1, 1, 2-trifluoro-1-butene;

wherein the reducing agent is iron powder or magnesium powder or zinc powder; the alcohol solvent is one of ethanol, n-butanol, isopropanol, ethylene glycol, and diethylene glycol.