JPH0640963A - Production of 1,1,1,2-tetrafluorotehane - Google Patents

Abstract

PURPOSE:To separate two-stage reaction products to give 1,1,1,2- tetrafluoroethane by a simplified separation method. CONSTITUTION:In a method for forming 1,1,1,2-tetrafluoroethane from trichloroethylene and HF by two-stage reaction, reaction products from a first reactor and a second reactor are joined and fed to a distillation column 3. HCI is distilled from the top of the column and a second side cut fraction 18 and a bottom liquid 17 are separated.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to trichlorethylene.
(Hereinafter referred to as CHCl = CCl ₂ or trichlene) and H
The present invention relates to a method for producing F134a, which is capable of efficiently producing 1,1,1,2 tetrafluoroethane (hereinafter referred to as CF ₃ —CH ₂ F or F134a) by reacting F with a simple apparatus.

[0002]

2. Description of the Related Art Conventionally, a method of reacting trichlene with HF is known for producing F134a. The above reaction cannot be achieved in one step, but is carried out by two steps under different reaction conditions. First, a reaction in the first step in which trichlene and HF are reacted to produce 1,1,1 trifluoro-2chloroethane (hereinafter referred to as CF ₃ —CH ₂ Cl or F133a), and F133a and HF are reacted. A second stage reaction is used which allows F134a to be produced.

The first stage reaction represented by the following formula (1) CHCl = CCl ₂ + 3HF → CF ₃ --CH ₂ Cl + 2HCl (1) is, for example, pressure: 4 kg / cm ² G, temperature: 250 ° C. HF /
Trichlene molar ratio: 6

The second stage reaction represented by the following formula (2): CF ₃ --CH ₂ Cl + HF → CF ₃ --CH ₂ F + HCl (2) is, for example, pressure: 4 kg / cm ² G, Temperature: 350 ° C, HF /
It is carried out under the condition of F133a molar ratio: 4.

Therefore, after carrying out the first-step reaction under the above conditions, HCl is separated through a purification step to adjust the reaction conditions and the second-step reaction is carried out to produce F134a,
Although F134a is purified by recovering this, there is a drawback that the distillation / separation process becomes long and the energy efficiency is poor.

[0006]

The problem to be solved by the present invention is that two processes under different conditions are carried out and the respective compounds are separately distilled and separated, which complicates the process and is inefficient.

[0007]

The present invention provides a first reactor for reacting trichlene and HF to produce F133a,
And the product of the second reactor for reacting F133a with HF to produce F134a is introduced into the distillation column, and H
Cl is distilled off and F1 containing a small amount of HF and the like is added.
It is divided into a side cut fraction containing 34a and F133a as a main component and a bottom liquid containing HF containing a small amount of trichlene as a main component. The side cut fraction is introduced into a separately provided purification step to recover F134a. HF is added to the F133a separated at that time, the molar ratio is adjusted, and the mixture is supplied to the second reactor for reaction. To the bottom liquid of the distillation column, trichlene and HF are added, the molar ratio is adjusted, and the solution is supplied to the first reactor for reaction.

FIG. 1 is a diagram showing an embodiment of the flow of the method for producing F134a according to the present invention. In the figure, reference numeral 1 is the first reactor,
2 is a second reactor.

Examples of preferable reaction conditions include, for example:
The first reactor 1 has a pressure of 4 kg / cm ² G, a temperature of 250 ° C.,
HF / trichlene molar ratio: 6, second reactor 2 pressure:
4 kg / cm ² G, temperature: 350 ° C., HF / F133a molar ratio: 4.

The reaction products of the first and second reactors 1 and 2 are combined and introduced into the distillation column 3 as a combined reaction product 15. In the distillation column 3, it is divided into a top distillate 16, a side cut fraction 18, and a bottom liquid 17.

The overhead distillate 16 is mainly purified by HCl and used for other purposes. The side-cut fraction 18 is mainly composed of F134a and F133a containing a small amount of HF, and is guided to a separately provided purification step 4 to recover F134a. At that time, the contained HF and F133a are separated, F133a is used as the raw material 19 of the second reactor, and HF is appropriately used as the raw material 1 of the first or second reactor.
Used as 3,14.

The bottom liquid 17 is mainly composed of HF containing a small amount of trichlene, a part of which is used for adjusting the raw material of the second reactor 2, and most of the rest is added with fresh HF and trichlene. It is used as a raw material 13 for the first reactor after its molar ratio and amount are adjusted. In addition, 11 and 12 are HF and trichlene introduced into the system, respectively.

Since the apparatus of the present invention has the above-mentioned structure, the products of the first and second reactors 1 and 2 are merged and supplied to the distillation column 3, and the distillation column 3 produces the desired product. There is F13
4a and F133a, by-produced HCl, and HF containing a small amount of trichlene that can be used to prepare the reaction raw material, and these are combined with new trichlene and HF that are supplementary raw materials to carry out the reaction. F134a can be manufactured efficiently.

[0014]

EXAMPLES Next, taking the flow of FIG. 1 as an example, the weight% of the components in each part and the amount of the combined reaction product 15 of the first and second reactors supplied to the distillation column 3 are set to 100. The flow rates are illustrated in Table 1.

[0015]

[Table 1]

As is clear from Table 1, the combined reaction products are separated by a distillation column, and from the side cut fraction, the desired product F134a and F1 which is a raw material of the second reactor are obtained.
33a is recovered, and by combining this with the bottom liquid, supplementary trichlene, and HF, the first and second reactor raw materials are adjusted, and by-product HCl is recovered.

[0017]

As described above, the F1 according to the present invention
In the production method of 34a, conventionally, the products of each reactor were separately separated by distillation, and these were combined with supplementary trichlene and HF to prepare the raw materials for the first and second reactors, whereas Since the products are separated by distillation and the raw materials for the reactor are adjusted by combining these with supplemental trichlene and HF, the distillation step is simplified and the energy consumption rate is reduced.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a flow of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st reactor 2 2nd reactor 3 Distillation column 4 Refining process 11 HF 12 introduced into a system trichlene 13 introduced into a system 13 Raw material introduced into a 1st reactor 14 Introduced into a 2nd reactor Raw material 15 Combined reaction product 16 Overhead distillate 17 Bottom liquid 18 Side cut distillate 19 Raw material circulated to the second reactor

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Toshio Oi 5-1 Ogimachi, Kawasaki-ku, Kawasaki-shi, Kanagawa Showa Denko KK Kawasaki Plant (72) Hidetoshi Nakayama 5-1 Ogimachi, Kawasaki-ku, Kawasaki-shi, Kanagawa Showa Denko Chemicals Laboratory

Claims (1)

[Claims] 1. In a method for producing 1,1,1,2 tetrafluoroethane in which trichlorethylene and HF are reacted, trichlorethylene and HF are reacted to
A first reactor for producing 1,1 trifluoro-2chloroethane and a second reaction for reacting 1,1,1 trifluoro-2chloroethane with HF to produce 1,1,1,2 tetrafluoroethane The product of the vessel was introduced into a distillation column, HCl was distilled off from the top of the column, and 1,1,1,2 tetrafluoroethane containing a small amount of HF and 1,
HF containing 1,1 trifluoro-2chloroethane as a main component, a side cut fraction, and a small amount of trichloroethylene
Is separated into the bottom liquid containing 1,2,4,4,3,4,3,4,3,2,3,4,3,4,3,4,3,2,3,4,3,4,3,4,3,4,3,4,3,4,3,4,3,4,3,2,3,2,3,4,4,6,6,6,6,1,1 and 1,4,3,4,6,6,6,9,10,10,10,10,10,10,10,10,10,10,16,10,10,10,16,10,10,10,10,10,10,10, to thereby collect 1,1,1,2 tetrafluoroethane.
Trifluoro-2chloroethane was added with HF, the molar ratio was adjusted and supplied to the second reactor for reaction, and the bottom liquid was added with trichlorethylene and HF to adjust the molar ratio and Feeding to 1 reactor and reacting 1,
A method for producing 1,1,2 tetrafluoroethane.