RU2246478C1 - Method for preparing 1,2,3,4-tetrachlorohexafluorobutane - Google Patents

Abstract

FIELD: organic chemistry, chemical technology.

SUBSTANCE: method for preparing 1,2,3,4-tetrachlorohexafluorobutane involves mixing 1-iodo-1,2-dichlorotrifluoroethane with CH₂Cl₂ and zinc powder in organic solvent medium. Process is carried out by continuous dosing a polar organic solvent to mixture containing zinc, 1-iodo-1,2-dichlorotrifluoroethane and CH₂Cl₂ and maintaining reaction temperature in the range 0-30^oC. Method is simple and provides elevating the yield of the end product.

EFFECT: improved preparing method.

2 cl, 1 tbl, 1 ex

Description

The invention relates to the field of chemistry, to a method for producing a class of chlorofluoroalkanes, namely the preparation of 1,2,3,4-tetrachlorohexafluorobutane, which is a raw material for the production of hexafluorobutane-1,3-diene.

Currently known methods for producing 1,2,3,4-tetrachlorohexafluorobutane can be divided into two groups.

First: fluorination and chlorofluorination of butenes and butanes according to the schemes:

[1,2,3,4]

Their common disadvantages include the use of highly toxic and difficult to use agents because of their corrosive activity (hydrogen fluoride, antimony halides, chlorine, chlorine halides).

The second group includes methods based on the dimerization of difluorodichloroethylene and 1-iodine-1,2-dichlorotrifluoroethane [5,6,7,8] according to the schemes:

Common disadvantages of this group of methods include the use of highly toxic reagents (fluorine, mercury oxide, mercury), as well as the difficulty of scaling processes due to extremely high activity of fluorine, and in the case of dimerization in the presence of mercury, quartz equipment must be used.

The closest in technical essence and the achieved result to the claimed technical solution is a method for producing 1,2,3,4-tetrachlorohexafluorobutane by dimerization of 1-iodine-1,2-dichlorotrifluoroethane in zinc in an environment of organic solvents [9]. The process is carried out by mixing 1-iodine-1,2-dichlorotriforgorethane, CH ₂ Cl ₂ acetic anhydride or ethyl acetate with zinc dust with stirring, yield up to 52%.

The disadvantages of the prototype method are the low yield of the target product and the difficulty of scaling associated with the large exothermic process and the inability to control it in large quantities.

The objective of the invention is to develop a simple method for producing 1,2,3,4-tetrachlorohexafluorobutane and increasing the yield of the target product.

The problem is achieved in that the process is carried out with a smooth dosage of the polar organic solvent in a mixture containing zinc, 1-iodine-1,2-dichlorotrifluoroethane and CH ₂ Cl ₂ while maintaining the reaction temperature of 0-30 ° C.

The above signs can increase the yield of the target product.

The above distinguishing features, each individually and all together, are aimed at solving the problem and are significant.

The use of significant distinguishing features in the prior art is not found, therefore, the proposed technical solution meets the patentability criterion of “novelty”.

A single set of new essential features with common, well-known provides a solution to the problem, is not obvious to specialists in this field of technology and indicates the compliance of the claimed technical solution with the patentability criterion of “inventive step”.

The invention is illustrated by a description of a specific, but non-limiting example of its implementation.

Example 1. Synthesis of 1,2,3,4-tetrachlorohexafluorobutane.

In a three-necked flask with a capacity of 0.5 dm ³ , equipped with a stirrer and a bath for cooling, load 200 g of 1-iodine-1,2-dichlorotrifluoroethane, 100 g of CH ₂ Cl ₂ , 30 g of zinc powder, at a temperature of 10-20 ° C and with vigorous stirring, 30 g of ethyl formate are gently metered over 3 hours. After dosing, the reaction mass is kept under stirring for 2 hours, then washed 2 times with water. The organic layer is rectified by selecting a fraction with a boiling point of 133-135 ° C, containing at least 98% 1,2,3,4-tetrachlorohexafluorobutane by GLC. Yield 84%.

The data of examples 1-5 are summarized in table.

Table No. Downloads, g Solvent The reaction temperature, ° C Reaction time, hours yield of 1,2,3,4-tetrachlorohexafluorobutane,% 1-iodine-1,2-dichlorotrifluoroethane zinc CH ₂ Cl ₂ Name Qty
g one 200 thirty one hundred ethyl formate thirty 10-20 3 84 2 200 thirty 80 ethyl acetate thirty 15-25 3 81 3 200 thirty 80 ethyl formate thirty 5-15 four 85 four 150 25 one hundred Acetone 40 0-10 5 73 5 one hundred twenty one hundred ethyl formate fifteen 30-10 2 76

Literature

1. The patent of Germany 949821, 09/27/56.

2. Germany patent 1020968, 05.20.58

3. English Patent 774737, 05.15.57.

4. US patent 2777004, 8.01.57.

5. US patent 2894042, 07.07.59.

6. English Patent 774104, 8.05.57.

7. US patent 2884466, 04/28/59.

8. English Patent 774103, 8.05.57.

9. Henne A.L. u.a. J. Am. Chem. Soc 77.2334 (1955) [121. 235] is a prototype.

Claims (1)

A method of producing 1,2,3,4-tetrachlorohexafluorobutane by mixing 1-iodine-1,2-dichlorotrifluoroethane with CH ₂ Cl ₂ and zinc powder in an organic solvent medium, characterized in that the process is carried out with a smooth dosage of a polar organic solvent in a mixture containing zinc, 1-iodine-1,2-dichlorotrifluoroethane and CH ₂ Cl ₂ while maintaining a reaction temperature of 0-30 ° C.