CN105820031A

CN105820031A - Synthesis technology of 1-bromine 2,2-polyvinylidene floride

Info

Publication number: CN105820031A
Application number: CN201610263118.2A
Authority: CN
Inventors: 闫宗刚; 李华新; 黄凯华; 周佳欢
Original assignee: NANTONG BAOKAI CHEMICAL CO Ltd
Current assignee: NANTONG BAOKAI CHEMICAL CO Ltd
Priority date: 2016-04-26
Filing date: 2016-04-26
Publication date: 2016-08-03

Abstract

The invention discloses a synthesis technology of 1-bromine 2,2-polyvinylidene floride. The technology comprises the following steps of: (1) brominating reaction, namely with vinylidene fluoride as a raw material, carrying out brominating addition reaction on the vinylidene fluoride and bromine to generate dibromodifluoroethane; and (2) elimination reaction, namely adding alkali to generated dibromodifluoroethane for hydrogen bromide eliminating reaction to generate the 1-bromine 2,2-polyvinylidene floride through infrared light irradiation in the presence of a catalyst. The yield of the technology reaches 90% or above; the product purity is 99.5% or above.

Description

A kind of 1-bromine 2, the synthesis technique of 2-difluoroethylene

Technical field

The invention belongs to the field of chemical synthesis, be specifically related to a kind of 1-bromine 2, the synthesis technique of 2-difluoroethylene.

Background technology

1-bromo-2,2-difluoroethylene is a kind of important fluorochemical intermediate and fluoropolymer Third monomer, can Using the intermediate as multiple fluoride-containing PMMA, synthesize for fluorine-containing medicines；Can be single as fluoropolymer the 3rd Body, improves vulcanization process and the serviceability of fluoroelastomer, improves the melt-processable of fluoropolymer and produces particularity Energy.

Prior art proposes many methods preparing 1-bromo-2,2-difluoroethylene.Such as, Dow Chemical Davis et al., United States Patent (USP) USP 3 of 1970, describes one and prepares 1-bromo-2 in 505,416,2-difluoroethylene Method.It uses tetrabromo Difluoroethane as raw material debrominate synthesize 1-bromo-2,2-difluoroethylene, according to one example, This reaction, in the there-necked flask of 1L, adds 4.14mol zinc powder, 200ml ethanol, is then slow added into 1.53mol tetrabromo two Fluoroethane and the mixed liquor of 280ml ethanol, reflux 2 hours, and dry ice condensation collection obtains 1-bromo-2,2-difluoroethylene, and yield is 82%。

Although the method can prepare 1-bromo-2,2-difluoroethylene with the higher yields of about 82%, but the method exists Following defect:

(i) the more difficult acquisition of raw material used, relatively costly；

(ii) it can produce a large amount of zinc bromide trade waste, it is difficult to industrially scalable is implemented.

Accordingly, it would be desirable to develop the 1-bromo-2 of a kind of efficient environmental protection, the manufacture method of 2-difluoroethylene, it is desirable to This preparation method not only has the advantage that reaction yield is high, but also has low cost, low garbage be prone to industry metaplasia The advantage produced.

Summary of the invention

Goal of the invention: in order to solve the deficiencies in the prior art, the invention provides a kind of 1-bromine 2, the conjunction of 2-difluoroethylene Become technique.

Technical scheme: a kind of 1-bromine 2, the synthesis technique of 2-difluoroethylene, comprises the steps:

The first step, bromination reaction: use vinylidene to be raw material and bromine carries out bromination additive reaction and generates dibromo Difluoroethane；

Second step, elimination reaction: by the dibromo Difluoroethane of above-mentioned generation in the presence of a catalyst, by the irradiation of infrared light, Add alkali to carry out eliminating reaction of hydrogen bromide generation 1-bromine 2,2-difluoroethylene；

Reaction equation is as follows:

。

As optimization: in the described first step, bromination additive reaction, use batch technology, bromine is used after metering vacuum Sucking in bromination reaction still, open stirring, be slowly passed through vinylidene gas, keep still temperature at 10 DEG C-80 DEG C, 3-12 is little in reaction Shi Hou, reaction terminates.

As optimization: in the described first step, bromination additive reaction, it is to react under illumination condition, preferably infrared light.

As optimization: in described second step, elimination reaction, use batch technology, first step product is pumped into after metering In reactor, adding proper catalyst, open stirring, slowly dropping 10%-40% alkali liquor, the condensed recovery of product i.e. obtains finished product.

As optimization: described 1-bromine 2, the synthetic reaction of 2-difluoroethylene must be carried out in the presence of a catalyst.

As optimization: described catalyst is 1-5% tetrabutyl ammonium bromide.

Beneficial effect: the yield of present invention process reaches >=90%, product purity >=99.5%.

The present invention compares additive method, the cost of raw material is low and be easy to get, operation is simple, mild condition, the three wastes are few and Disposable, be prone to industrialized production；Yield and conversion ratio all improve a lot；

The present invention compares additive method, additive reaction have only at ambient pressure can, and carry out under photocatalysis, relatively In having saved cost with other catalyst, and other impurity will not be introduced, improve the utilization rate of bromine；Elimination reaction uses The mode of dropping alkali, can effectively control the speed of reaction, it is to avoid the Concerning Flooding Phenomenon of easy generation.

Accompanying drawing explanation

Fig. 1 is the process flow diagram of the present invention.

Detailed description of the invention

Below in conjunction with specific embodiment, the invention will be further described.

Specific embodiment 1

As it is shown in figure 1, a kind of 1-bromine 2, the synthesis technique of 2-difluoroethylene, comprise the steps:

The first step, bromination reaction: use vinylidene to be raw material and bromine carries out bromination additive reaction and generates dibromo Difluoroethane； Use batch technology, bromine is sucked in bromination reaction still by vacuum after metering, opens stirring, be slowly passed through vinylidene gas Body, keeps still temperature at 10 DEG C, and after reacting 3 hours, reaction terminates.

Second step, elimination reaction: by the dibromo Difluoroethane of above-mentioned generation in the presence of a catalyst, by the photograph of infrared light Penetrate, add alkali and carry out eliminating reaction of hydrogen bromide generation 1-bromine 2,2-difluoroethylene；Use batch technology, by first step product through metering After pump in reactor, add proper catalyst, open stirring, slowly drip 10% alkali liquor, the condensed recovery of product is i.e. become Product.

Reaction equation is as follows:

。

Described 1-bromine 2, the synthetic reaction of 2-difluoroethylene must be carried out in the presence of a catalyst, and described catalyst is 1% 4 Butylammonium bromide.

Specific embodiment 2

The first step, bromination reaction: use vinylidene to be raw material and bromine carries out bromination additive reaction and generates dibromo Difluoroethane； Use batch technology, bromine is sucked in bromination reaction still by vacuum after metering, opens stirring, be slowly passed through vinylidene gas Body, keeps still temperature at 80 DEG C, and after reacting 12 hours, reaction terminates.

Second step, elimination reaction: by the dibromo Difluoroethane of above-mentioned generation in the presence of a catalyst, by the photograph of infrared light Penetrate, add alkali and carry out eliminating reaction of hydrogen bromide generation 1-bromine 2,2-difluoroethylene；Use batch technology, by first step product through metering After pump in reactor, add proper catalyst, open stirring, slowly drip 40% alkali liquor, the condensed recovery of product is i.e. become Product.

Reaction equation is as follows:

。

Described 1-bromine 2, the synthetic reaction of 2-difluoroethylene must be carried out in the presence of a catalyst, and described catalyst is 5% 4 Butylammonium bromide.

Specific embodiment 3

The first step, bromination reaction: use vinylidene to be raw material and bromine carries out bromination additive reaction and generates dibromo Difluoroethane； Use batch technology, bromine is sucked in bromination reaction still by vacuum after metering, opens stirring, be slowly passed through vinylidene gas Body, keeps still temperature at 60 DEG C, and after reacting 8 hours, reaction terminates.

Second step, elimination reaction: by the dibromo Difluoroethane of above-mentioned generation in the presence of a catalyst, by the photograph of infrared light Penetrate, add alkali and carry out eliminating reaction of hydrogen bromide generation 1-bromine 2,2-difluoroethylene；Use batch technology, by first step product through metering After pump in reactor, add proper catalyst, open stirring, slowly drip 30% alkali liquor, the condensed recovery of product is i.e. become Product.

Reaction equation is as follows:

。

Described 1-bromine 2, the synthetic reaction of 2-difluoroethylene must be carried out in the presence of a catalyst, and described catalyst is 3% 4 Butylammonium bromide.

The present invention is not limited to above-mentioned preferred forms, and anyone can show that under the enlightenment of the present invention other are various The product of form, no matter but in its shape or structure, make any change, every have same as the present application or akin skill Art scheme, within all falling within protection scope of the present invention.

Claims

1. a 1-bromine 2, the synthesis technique of 2-difluoroethylene, it is characterised in that: comprise the steps:

The first step, bromination reaction: using vinylidene is that raw material carries out additive reaction generation dibromo by photocatalytic and bromine Difluoroethane；

Second step, elimination reaction: by the dibromo Difluoroethane of above-mentioned generation in the presence of a catalyst, add alkali and carry out elimination reaction life Become 1-bromine 2,2-difluoroethylene；

Reaction equation is as follows:

。

1-bromine 2 the most according to claim 1, the synthesis technique of 2-difluoroethylene, it is characterised in that: the described first step, bromine Change in additive reaction, use batch technology, bromine is sucked in bromination reaction still by vacuum after metering, opens stirring, slowly lead to Entering vinylidene gas, keep still temperature at 10 DEG C-80 DEG C, after reacting 3-12 hour, reaction terminates.

1-bromine 2 the most according to claim 1, the synthesis technique of 2-difluoroethylene, it is characterised in that: the described first step, bromine Change in additive reaction, be to react under illumination condition, preferably infrared light.

1-bromine 2 the most according to claim 1, the synthesis technique of 2-difluoroethylene, it is characterised in that: described second step, disappear In dereaction, use batch technology, first step product pumped in reactor after metering, add proper catalyst, open stirring, Slowly dropping 10%-40% alkali liquor, the condensed recovery of product i.e. obtains finished product.

1-bromine 2 the most according to claim 1, the synthesis technique of 2-difluoroethylene, it is characterised in that: described 1-bromine 2,2-bis- The synthetic reaction of fluorothene must be carried out in the presence of a catalyst.

1-bromine 2 the most according to claim 5, the synthesis technique of 2-difluoroethylene, it is characterised in that: described catalyst is 1- 5% tetrabutyl ammonium bromide.