CN110997604A

CN110997604A - Method for producing 1, 2-dichloro-1, 2-difluoroethane (HCFC-132), method for producing 1-chloro-1, 2-difluoroethylene (HCFO-1122 a), and method for separating HCFC-132

Info

Publication number: CN110997604A
Application number: CN201880050223.5A
Authority: CN
Inventors: 臼井隆; 加留部大辅
Original assignee: Daikin Industries Ltd
Current assignee: Daikin Industries Ltd
Priority date: 2017-07-31
Filing date: 2018-07-04
Publication date: 2020-04-10
Also published as: JP2019026601A; CN116462566A; CN116462565A; CN114634398A; WO2019026515A1; JP6610625B2

Abstract

The present invention provides a production process which is easier to handle than conventional processes because chlorine and highly toxic carbon tetrachloride are not used and which has a high selectivity for HCFC-132. The invention specifically provides a method for preparing HCFC-132, which is characterized by comprising the following steps: a compound represented by the general formula (1): a step in which halogenated ethane represented by CFClX-CFClX (wherein X is Cl, Br, I or H, independently of one another; wherein at least one of X is Cl, Br or I.) is reduced in the presence of a reducing agent to produce 1, 2-dichloro-1, 2-difluoroethane (HCFC-132).

Description

Method for producing 1, 2-dichloro-1, 2-difluoroethane (HCFC-132), method for producing 1-chloro-1, 2-difluoroethylene (HCFO-1122 a), and method for separating HCFC-132

Technical Field

The present invention relates to a method for producing 1, 2-dichloro-1, 2-difluoroethane (HCFC-132), a method for producing 1-chloro-1, 2-difluoroethylene (HCFO-1122 a), and a method for separating HCFC-132.

Background

Conventionally, a method of producing 1-chloro-1, 2-difluoroethylene (HCFO-1122 a) by reacting 1, 2-difluoroethylene (HFO-1132) with chlorine to produce 1, 2-dichloro-1, 2-difluoroethane (HCFC-132) and subjecting HCFC-132 to a dehydrochlorination reaction is known (for example, patent document 1).

However, in the above production method, halogen chlorine which is difficult to handle is used for producing HCFC-132, and carbon tetrachloride which has high toxicity is used as a solvent, and therefore, there is room for improvement in order to produce HCFO-1122 a easily and efficiently.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2015-120670

Disclosure of Invention

Technical problem to be solved by the invention

The object of the present invention is to provide a method for producing HCFC-132 using a reducing agent, a method for producing HCFO-1122 a using HCFC-132 obtained by the production method as a starting compound, and a method for producing HCFC-132 and HCFO-1122 a with high selectivity in the methods. In addition, the invention aims to provide a method for separating HCFC-132.

Technical solution for solving technical problem

The present inventors have made extensive studies to achieve the above object, and as a result, have found that the above object can be achieved when a specific halogenated ethane as a raw material compound is reduced with a reducing agent, and have completed the present invention.

That is, the present invention relates to a method for producing HCFC-132, a method for producing HCFO-1122 a, and a method for separating HCFC-132 described below.

1. A method for producing HCFC-132, comprising:

a compound represented by the general formula (1): a step in which halogenated ethane represented by CFClX-CFClX (wherein X is Cl, Br, I or H, independently of one another; wherein at least one of X is Cl, Br or I.) is reduced in the presence of a reducing agent to produce 1, 2-dichloro-1, 2-difluoroethane (HCFC-132).

2. The production process according to item 1, wherein the reducing agent is a formate.

3. The production method according to item 1 or 2, wherein the reduction step is performed at a temperature in the range of 20 ℃ to 100 ℃.

4. The production process according to any one of the above 1 to 3, wherein the halogenated ethane represented by the general formula (1) is 1,1,2, 2-tetrachloro-1, 2-difluoroethane (CFC-112).

5. A method of making HCFO-1122 a, comprising:

(i) a compound represented by the general formula (1): a step in which halogenated ethane represented by CFClX-CFClX (wherein X is Cl, Br, I or H, independently of one another; wherein at least one of X is Cl, Br or I.) is reduced in the presence of a reducing agent to produce a mixture containing HCFC-132; and

(ii) (ii) subjecting HCFC-132 in the mixture produced in the step (i) to a dehydrochlorination reaction in the presence of a base to produce 1-chloro-1, 2-difluoroethylene (HCFO-1122 a).

6. The process for producing HCFO-1122 a according to item 5, further comprising a step of separating HCFC-132 from the mixture between the step (i) and the step (ii), wherein the HCFC-132 is supplied to the step (ii).

7. A process for the separation of HCFC-132 wherein a mixture of HCFC-132 and a boiling point below-10 ℃ is separated under pressure.

8. The separation process according to item 7, wherein the pressure for pressurization is 0.01 to 2.0 MPa.

9. The separation method according to item 7 or 8, wherein the mixture having a boiling point of-10 ℃ or lower contains CO₂、N₂At least one of HCFO-1122 a and 2-chloro-1, 1-difluoroethylene (HCFC-1122).

10. A composition comprising: HCFC-132, and at least one compound selected from the group consisting of 1,1, 2-trichloro-1, 2-difluoroethane (HCFC-122 a), 1, 2-dichloro-1, 1-difluoroethane (HCFC-132 b), and 1, 1-dichloro-2, 2-difluoroethane (HCFC-132 a).

11. A composition comprising: HCFO-1122 a, and at least one compound selected from the group consisting of HCFC-132, HCFC-1122 and 1, 2-dichloro-1, 2-difluoroethylene (CFC-1112).

12. The composition of claim 11, which is a refrigerant composition.

ADVANTAGEOUS EFFECTS OF INVENTION

The present invention is a method for producing HCFC-132 by hydrogenating a specific halogenated ethane with a reducing agent, and a method for producing HCFO-1122 a by using HCFC-132 obtained by the production method as a raw material compound, and therefore, the method is easier to handle than conventional methods because chlorine and highly toxic carbon tetrachloride are not used, and the selectivity of HCFC-132 and HCFO-1122 a is high.

Detailed Description

The method for producing HCFC-132, the method for producing HCFO-1122 a and the method for separating HCFC-132 of the present invention will be described in detail below. In the present invention, "pressure" means gauge pressure (i.e., a method of expressing a pressure at atmospheric pressure of 0) without specific explanation.

Process for producing 1, 2-dichloro-1, 2-difluoroethane (HCFC-132)

The process for producing 1, 2-dichloro-1, 2-difluoroethane (HCFC-132) of the present invention comprises: a compound represented by the general formula (1): a step wherein halogenated ethane represented by CFClX-CFClX (wherein X is Cl, Br, I or H, independently of one another; wherein at least one of X is Cl, Br or I.) is reduced in the presence of a reducing agent to produce HCFC-132.

The reaction of the halogenated ethanes of the general formula (1) to HCFC-132 may be carried out by hydrogenating the halogenated ethanes of the general formula (1) in a suitable solvent in the presence of a reducing agent.

Examples of reducing agents include hydrogen, lithium aluminum hydride, formic acid, formate salts, sodium borohydride, sodium cyanoborohydride, and sodium triacetoxyborohydride.

Among these reducing agents, formate is preferable from the viewpoint of obtaining HCFC-132 in a high yield. As the formate salt, sodium formate, potassium formate, and ammonium formate can be used, and sodium formate and ammonium formate are preferable from the viewpoint of easy water solubility and easy handling.

In the reduction reaction, from the viewpoint of obtaining HCFC-132 at a high yield, a catalyst such as palladium black, palladium/carbon, platinum oxide, platinum black, or raney nickel may be used.

The reaction temperature in the reduction reaction using a reducing agent is preferably 20 to 100 ℃, more preferably 20 to 80 ℃, and still more preferably 30 to 70 ℃ from the viewpoint of obtaining HCFC-132 with high selectivity. The reduction reaction is usually preferably carried out at 0.0 to 2.0MPa, more preferably at 0.0 to 1.5 MPa.

The reduction reaction is completed within 1 to 20 hours from the start of the reaction.

The amount of the reducing agent is preferably 1 to 10mol equivalent, more preferably 1.5 to 8mol equivalent, and further preferably 1.5 to 5mol equivalent, based on 1mol of the halogen to be reduced in the general formula (1).

The solvent is not limited as long as it does not adversely affect the reduction reaction. As examples of such a solvent, at least 1 solvent selected from the group consisting of water, ethers, amides, nitriles, and alcohols may be used, or the solvent may be mixed with another solvent and used. The ethers are not particularly limited, and examples thereof include diethyl ether, tetrahydrofuran, diphenyl ether, anisole, and dimethoxybenzene. The amide is not particularly limited, and examples thereof include N, N-Dimethylformamide (DMF) and N, N-Dimethylacetamide (DMAC). The nitrile is not particularly limited, and examples thereof include acetonitrile, propionitrile, and benzonitrile. The alcohol is not particularly limited, and examples thereof include methanol, ethanol, propanol, isopropanol, n-butanol, t-butanol, and isoamyl alcohol.

Of these solvents, at least 1 selected from water, ethers, amides and alcohols is preferable, and DMF is more preferable from the viewpoint of obtaining HCFC-132 with high selectivity.

The amount of the solvent is not particularly limited as long as the effect of the present invention is not significantly impaired, and is, for example, preferably 1 to 50 parts by mass, more preferably 2 to 20 parts by mass, and still more preferably 2 to 10 parts by mass, based on 1 part by mass of the halogenated ethane of the general formula (1).

Examples of the halogenated ethane represented by the general formula (1) include 1,1,2, 2-tetrachloro-1, 2-difluoroethane (CFC-112), 1, 2-dibromo-1, 2-dichloro-1, 2-difluoroethane, 1, 2-dichloro-1, 2-difluoro-1, 2-diiodoethane, 1-bromo-1, 2, 2-trichloro-1, 2-difluoroethane, 1, 2-trichloro-1, 2-difluoro-2-iodoethane, 1-bromo-1, 2-dichloro-1, 2-difluoro-2-iodoethane, 1, 2-trichloro-1, 2-difluoroethane, 1-bromo-1, 2-dichloro-1, 2-difluoroethane, and 1, 2-dichloro-1, 2-difluoro-1-iodoethane.

Among these halogenated ethanes, CFC-112 is preferred in the present invention from the viewpoint of obtaining HCFC-132 and HCFO-1122 a with high selectivity.

The purity of the halogenated ethane represented by the general formula (1) is preferably 60 to 99.99 mol%, more preferably 80 to 99.99 mol%, and still more preferably 90 to 99.99 mol%, from the viewpoint of increasing the conversion of the halogenated ethane and increasing the selectivity of HCFC-132 as the target.

When the reduction reaction is carried out, a radical generator may be used. Examples of the radical generator include organic radical initiators such as azo compounds and organic peroxides, and inorganic radical initiators such as persulfates, cerium salts, and hydrogen peroxide.

Examples of the azo compound include 2,2 ' -azobis (2-methylpropionamidine) dihydrochloride, 2 ' -azobis (isobutyronitrile), 4 ' -azobis (4-cyanovaleric acid), 1 ' -azobis (cyclohexanecarbonitrile), 2 ' -azobis (2-methylpropane), 2 ' -azobis (2-methylpropionitrile), and α ' -azobisisobutylamidine dihydrochloride.

Examples of the organic peroxide include methyl ethyl ketone peroxide, cyclohexanone peroxide, acetylacetone peroxide, 1-bis (t-hexylperoxy) -3, 3, 5-trimethylcyclohexane, and 1, 1-bis (t-hexylperoxy) cyclohexane.

Examples of the persulfate include ammonium persulfate, sodium persulfate, and potassium persulfate.

Examples of the cerium salt include ammonium cerium (IV) nitrate, cerium (IV) sulfate, ammonium cerium (IV) sulfate, cerium (IV) hydroxide, and cerium (IV) oxide.

Among these radical generators, from the viewpoint of obtaining HCFC-132 in high yield, azo compounds such as persulfate salts of Ammonium Persulfate (APS), 2 '-azobis (2-methylpropionamidine) dihydrochloride, and 2, 2' -azobis (isobutyronitrile) are preferable.

The amount of the radical generator to be incorporated may be a catalyst amount relative to the amount of the halogenated ethane represented by the general formula (1), and is preferably 0.01 to 5mol, more preferably 0.05 to 1mol, and still more preferably 0.1 to 0.5mol relative to 1mol of the halogenated ethane represented by the general formula (1) from the viewpoint of increasing the reaction rate and suppressing the production of by-products.

The composition of the present invention comprises: HCFC-132 obtained by the production process of the present invention; and at least one compound selected from the group consisting of 1,1, 2-trichloro-1, 2-difluoroethane (HCFC-122 a), 1, 2-dichloro-1, 1-difluoroethane (HCFC-132 b), and 1, 1-dichloro-2, 2-difluoroethane (HCFC-132 a).

Process for producing 1-chloro-1, 2-difluoroethylene (HCFO-1122 a)

The process for producing 1-chloro-1, 2-difluoroethylene (HCFO-1122 a) of the present invention comprises:

(i) a compound represented by the general formula (1): a step in which a halogenated ethane represented by CFClX-CFClX (wherein X is independently Cl, Br, I or H; wherein at least one position of X is Cl, Br or I.) is reduced in the presence of a reducing agent to produce a mixture containing HCFC-132; and

(ii) (ii) subjecting HCFC-132 in the mixture produced in the step (i) to a dehydrochlorination reaction in the presence of a base to produce HCFO-1122 a.

In the production method of the present invention, it is preferable that a step of separating HCFC-132 from the mixture produced in the step (i) is further included between the step (i) and the step (ii), and the HCFC-132 is supplied to the step (ii).

The method for separating HCFC-132 from the mixture produced in step (i) of the production process of the present invention is not particularly limited, but it is preferable to separate HCFC-132 in a reactor under pressure.

The pressure for pressurizing is preferably 0.01 to 2.0MPa, more preferably 0.1 to 1.5MPa, and still more preferably 0.5 to 1.0MPa, from the viewpoint of the recovery rate and purity of HCFC-132.

The mixture containing HCFC-132 obtained in step (i) of the production method of the present invention contains, in addition to HCFC-132, 1, 2-trichloro-1, 2-difluoroethane (HCFC-122 a), 1, 2-dichloro-1, 1-difluoroethane (HCFC-132 b), 1-dichloro-2, 2-difluoroethane (HCFC-132 a), carbon dioxide, nitrogen, and the like.

The purity of HCFC-132 before separation in the mixture is preferably 60 mol% to 99.99 mol%, more preferably 80 mol% to 99.99 mol%, and still more preferably 90 mol% to 99.99 mol%.

The mixture containing HCFC-132 obtained in step (i) of the production process of the present invention preferably contains a compound having a boiling point of-10 ℃ or lower, more preferably-30 ℃ or lower, and still more preferably-50 ℃ or lower, from the viewpoint of the recovery rate and purity of HCFC-132.

In the present invention, HCFC-132 in the mixture produced in step (i) is subjected to a dehydrochlorination reaction in the presence of a base to produce HCFO-1122 a. Specifically, HCFC-132 in the mixture produced in step (i) is brought into contact with an aqueous alkaline solution to perform a dehydrochlorination reaction, thereby producing HCFO-1122 a.

The alkaline aqueous solution is not particularly limited as long as it is an aqueous solution of an alkaline compound capable of performing the above-described dehydrochlorination reaction. Specific examples thereof include aqueous solutions of an inorganic basic compound such as an alkali metal hydroxide such as an aqueous lithium hydroxide solution, an aqueous potassium hydroxide solution and an aqueous sodium hydroxide solution, an alkaline earth metal hydroxide such as a calcium hydroxide, an organic basic compound such as an amine, and an alkali metal alkoxide.

Among these alkaline aqueous solutions, from the viewpoint of improving the reactivity and the selectivity of HCFO-1122 a, an aqueous solution of potassium hydroxide, sodium hydroxide, calcium hydroxide, or the like is preferably used, and an aqueous solution of potassium hydroxide is more preferably used.

The concentration of the alkaline aqueous solution used in the dehydrochlorination reaction is preferably 1 to 50% by mass, more preferably 10 to 40% by mass, and still more preferably 20 to 30% by mass, from the viewpoint of promoting the dehydrochlorination reaction. The amount of the basic aqueous solution used in the above-mentioned dehydrochlorination reaction is preferably adjusted to an amount of 1 to 10mol equivalent, more preferably 1.5 to 5mol equivalent, and still more preferably 2 to 5mol equivalent, based on the amount of HCFC-132 after separation.

When the separated HCFC-132 is dehydrochlorinated, the HCFC-132 may be dehydrochlorinated by contacting with an aqueous alkaline solution in the presence of a phase transfer catalyst.

The phase transfer catalyst is not particularly limited, and quaternary ammonium salts such as tetrabutylammonium bromide (TBAB), trimethylbenzylammonium bromide, triethylbenzylammonium bromide, trioctylmethylammonium chloride (TOMAC), and the like; phosphonium salts such as tetrabutylphosphonium chloride (TBPC); crown ethers such as 15-crown 5 and 18-crown 6, and publicly known substances such as alkylammonium salts, carboxylates, and alkylsulfonates. Among them, quaternary ammonium salts are preferable, and for example, tetrabutylammonium bromide, trioctylmethylammonium bromide, Aliquat336 and the like can be preferably used.

Among these phase transfer catalysts, Aliquat336 is preferred from the viewpoint of economy and safety.

The amount of the phase transfer catalyst is preferably 0.1 to 40 parts by mass, more preferably 1 to 20 parts by mass, and still more preferably 10 to 20 parts by mass, based on 100 parts by mass of the separated HCFC-132.

Specifically, the dehydrochlorination is carried out by introducing the separated HCFC-132 and the aqueous alkaline solution into a reactor, and stirring them so as to be in sufficient contact with each other.

The reaction temperature in the above-mentioned dehydrochlorination reaction is not particularly limited, but is preferably 0 to 100 ℃ and more preferably 40 to 80 ℃ from the viewpoint of improving the reactivity and the selectivity of HCFO-1122 a.

The above-mentioned dehydrochlorination reaction is preferably carried out under pressure.

The pressure for pressurizing is preferably 0.01 to 2.0MPa, more preferably 0.1 to 1.5MPa, and still more preferably 0.2 to 1.0MPa, from the viewpoint of improving the reactivity and the selectivity of HCFO-1122 a. The hydrochloric acid removal reaction is completed within 1 to 50 hours from the start of the reaction.

In the HCFO-1122 a of the present invention, the above-mentioned dehydrochlorination reaction proceeds to produce HCFO-1122 a as a product. The HCFO-1122 a thus produced can be analyzed by a conventional method such as Gas Chromatography (GC) or NMR, cooled and concentrated, and then recovered in a container.

The composition of the present invention contains HCFO-1122 a obtained by the production process of the present invention and at least one compound selected from HCFC-132, 2-chloro-1, 1-difluoroethylene (HCFC-1122) and 1, 2-dichloro-1, 2-difluoroethylene (CFC-1112). Further, the composition is preferably a refrigerant composition.

Process for the separation of 1, 2-dichloro-1, 2-difluoroethane (HCFC-132)

The method for separating HCFC-132 of the present invention is a method for separating HCFC-132 from a mixture having a boiling point of-10 ℃ or lower under pressure, and preferably, HCFC-132 is separated under pressure in a reactor.

The mixture having a boiling point of-10 ℃ or lower preferably contains CO₂、N₂At least one of HCFO-1122 a and 2-chloro-1, 1-difluoroethylene (HCFC-1122).

Examples

The present invention will be specifically described below with reference to examples and comparative examples. However, the present invention is not limited to the scope of the embodiments.

Production of 1, 2-dichloro-1, 2-difluoroethane (HCFC-132)

(example 1)

A100 ml flask was charged with 0.05mol of CFC-112, 0.15mol of sodium formate, 0.015mol of Ammonium Persulfate (APS) and 50ml of DMF, and the mixture was heated to 40 ℃ under atmospheric pressure, followed by stirring to effect reaction. After the reaction was started, the consumption of CFC-112 and HCFC-122 a was confirmed by appropriate gas chromatography analysis, and then the reaction mixture was allowed to stand for cooling. Thereafter, water was added thereto and the mixture was stirred to obtain HCFC-132 as a free organic phase.

(example 2)

2.0mol of CFC-112, 6mol of ammonium formate and 800ml of DMF were added to a 3L flask, and the mixture was heated to 40 ℃ under atmospheric pressure, and then stirred. APS was added in an amount of 0.1mol per one time to an amount of 0.6mol, and the mixture was reacted. After the reaction was started, HCFC-132 was obtained in the same manner as in example 1.

(example 3)

2.5mol of CFC-112, 9.6mol of ammonium formate, 0.75mol of APS and 500ml of DMF were added to a 3-liter autoclave, and stirring was started after the temperature was raised to 40 ℃. APS was added in an amount of 0.1mol per time to the charged amount to 1.1 mol. Thereafter, the reaction was carried out under a pressure condition in which the back pressure valve was set to 1.0 MPa. The recovery operation after the reaction is carried out under a pressure of 0.01 to 1.0MPa when the gas phase is extracted. Thereafter, HCFC-132 was obtained in the same manner as in example 1.

The results of examples 1 to 3 are shown in Table 1.

[ Table 1]

In example 1, sodium formate was used as a formate salt to carry out a reaction, and the change with time of the reaction was analyzed and followed by GC. As a result, it was found that HCFC-122 a was produced first, CFC-112 was produced thereafter, and HCFC-132 was produced as the desired product.

In example 2, the reaction was carried out using ammonium formate as the formate salt, and HCFC-132 as the target compound was obtained with a selectivity of 92 mol%. As a result of analyzing and tracing the change with time of the reaction by GC, it was found that HCFC-122 a was produced first, CFC-112 was produced later, and HCFC-132 was finally produced as the target product. After the reaction was completed, the organic phase was recovered and the weight was measured to obtain 100g (yield 37 mol%).

In example 3, ammonium formate was used as a formate salt, and the reaction was carried out in an autoclave under pressurized conditions, whereby HCFC-132 as an object was obtained at a selectivity of 81 mol%. After completion of the reaction, the liquid phase was cooled with ice water and then the pressure was released, and after separating the liquid, the weight of the organic phase was measured to obtain 202g (yield: 60 mol%), and the recovered amount of HCFC-132 was increased by separation under pressure.

Production of 1-chloro-1, 2-difluoroethylene (HCFO-1122 a)

(example 4)

Into a 500ml autoclave were charged HCFC-1320.38 mol obtained in example 3 and 1.7g of quaternary ammonium salt (Aliquat336) as a phase transfer catalyst, and after cooling to 0 ℃ a 20% KOH aqueous solution (KOH 0.56mol) was added dropwise. And after the dripping is finished, heating to 35-40 ℃ and stirring. When the organic phase in the flask had disappeared, the reaction was terminated and the amount of recovered HCFO-1122 a was measured to find that it was 33 g.

(example 5)

HCFC-1320.6 mol and Aliquat 33610 g obtained in example 3 were charged into a 500ml autoclave, and after cooling to 0 ℃ a 32% KOH aqueous solution (KOH 1.2mol) was added dropwise. And after the dripping is finished, heating to 35-40 ℃ and continuously stirring. The reaction was terminated when the organic phase in the flask had disappeared, and the recovered amount of HCFO-1122 a was measured to find that it was 56 g.

The results of examples 4 and 5 are shown in table 2.

[ Table 2]

The fraction obtained in example 4 was analyzed by a Gas Chromatograph (GC), and the gas composition was calculated from the area ratio of the GC. The results are shown in Table 3.

[ Table 3]

Compound (I)	Concentration (mol%)
		Z-1122a	39
E-1122a	56
		1122	2.7
1112	0.4
		132a	0.4
132	1.1

The fraction obtained in example 5 was analyzed by a Gas Chromatograph (GC), and the gas composition was calculated from the area ratio of the GC. The results are shown in Table 4.

[ Table 4]

In example 4, KOH was added at 1.2eq to 132, and as a result, 1122a, which is the target product, was obtained in a yield of 90 mol% and a purity of 95 mol%. From the gas phase compositions shown in table 3, it was confirmed that 1122 and 1112 were produced in addition to 1122 a. It is considered that 1122 is a compound obtained by the dehydrochlorination of the by-product 132a of the reaction in example 3, and 1112 is a compound obtained by the dehydrochlorination of example 3 at 112.

In example 5, 2.0eq of KOH was added to 132 to carry out the reaction, whereby 1122a, which is the target product, was obtained in a yield of 95 mol% and a purity of 99 mol%. In example 5, the temperature was increased compared to example 4, and the amount of KOH aqueous solution and the amount of Aliquat336 added were increased, thereby shortening the reaction time. The concentration of 132a is very low and is therefore recorded as a trace amount.

1122a production by hydrogenation of 1112 using Pd/C as a transition metal catalyst

Comparative example 1

A200 ml autoclave was charged with 7.1g (0.054mol) of 1112, 1.0g of Pd/C (3 wt% Pd, 0.5 mol% of Pd/1112) and 50ml of 1N KOHaq, and then evacuated to perform hydrogen substitution so as to attain 0.1 to 0.5 MPaG. The autoclave was stirred at a temperature of 0 ℃. 24 hours after the start of the reaction, H₂The pressure no longer decreased, thus stopping the reaction.

The fraction obtained in comparative example 1 was analyzed by GC, and the gas phase composition was calculated from the area ratio of GC. The results are shown in Table 5.

[ Table 5]

In comparative example 1, 1122a, which is the target product, was obtained in a yield of 4 mol% and a purity of 20 mol%. The gas phase composition shown in table 5 gave a very low 1122a concentration as compared with examples 4 and 5.

Claims

1. A method for producing HCFC-132, comprising:

a compound represented by the general formula (1): a step of reducing a halogenated ethane represented by CFClX-CFClX in the presence of a reducing agent to produce 1, 2-dichloro-1, 2-difluoroethane (HCFC-132), wherein in formula (1), X is independently Cl, Br, I or H, and at least one of X is Cl, Br or I.

2. The manufacturing method according to claim 1, wherein:

the reducing agent is formate.

3. The manufacturing method according to claim 1 or 2, characterized in that:

the step of reducing is carried out at a temperature in the range of 20 to 100 ℃.

4. The production method according to any one of claims 1 to 3, characterized in that:

the halogenated ethane shown in the general formula (1) is 1,1,2, 2-tetrachloro-1, 2-difluoroethane (CFC-112).

5. A method for producing HCFO-1122 a, comprising:

(i) a compound represented by the general formula (1): a step in which a halogenated ethane represented by CFClX-CFClX is reduced in the presence of a reducing agent to form a mixture containing HCFC-132, wherein in formula (1), X is Cl, Br, I or H, and at least one of X is Cl, Br or I; and

6. The process for producing HCFO-1122 a according to claim 5, wherein:

between the step (i) and the step (ii), a step of separating HCFC-132 from the mixture is further included, and the HCFC-132 is supplied to the step (ii).

7. A method for separating HCFC-132 is characterized in that:

separating under pressure a mixture of HCFC-132 and boiling point below-10 ℃.

8. The separation method of claim 7, wherein:

the pressure for pressurizing is 0.01 to 2.0 MPa.

9. The separation method according to claim 7 or 8, wherein:

the mixture with boiling point below-10 deg.C contains CO₂、N₂At least one of HCFO-1122 a and 2-chloro-1, 1-difluoroethylene (HCFC-1122).

10. A composition comprising:

HCFC-132, and

at least one compound selected from the group consisting of 1,1, 2-trichloro-1, 2-difluoroethane (HCFC-122 a), 1, 2-dichloro-1, 1-difluoroethane (HCFC-132 b), and 1, 1-dichloro-2, 2-difluoroethane (HCFC-132 a).

11. A composition comprising:

HCFO-1122 a, and

at least one compound selected from HCFC-132, HCFC-1122 and 1, 2-dichloro-1, 2-difluoroethylene (CFC-1112).

12. The composition of claim 11, wherein:

the composition is a refrigerant composition.