JP3207928B2 - Method for producing 1,1,1,2-tetrafluoroethane - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a (hereinafter referred to as CHCl = CCl ₂ or trichlorethylene) trichlorethylene with HF
To produce 1,1,1,2-tetrafluoroethane (hereinafter referred to as CF ₃ .CH ₂ F or F-134a) efficiently using a simple apparatus.
It relates to the production method of a.

[0002]

2. Description of the Related Art Conventionally, for producing F-134a, a method of reacting trichlene with HF is known. The above reaction cannot be achieved in one step, but is carried out by two steps under different reaction conditions. First, trichlene represented by the formula (1) is reacted with HF to give 1,1,1-trifluoro-2-chloroethane (hereinafter referred to as CF ₃ .CH ₂ Cl or F-
133a), the second stage of reacting HF with F-133a represented by CHCl = CCl ₂ + 3HF → CF ₃ .CH ₂ Cl + 2HCl (1) and formula (2) , CF ₃ .CH ₂ Cl + HF → CF ₃ .CH ₂ F + HCl (2)

All of the above reactions are carried out in the presence of, for example, an alumina or chromina catalyst, but the reaction conditions are different. In the first stage reaction, the pressure is 4 kg / cm ² , and the temperature is 2
50 ° C., HF / trichlene molar ratio: 6, pressure in the second stage reaction: 4 kg / cm ² , temperature: 350 ° C., HF /
The reaction is carried out at a molar ratio of F-133a of 4.

Therefore, after performing the first reaction under the above conditions, HCl is removed in the purification step, the reaction conditions such as the molar ratio of F-133a to HF are adjusted, and the second stage reaction is carried out.
-134a was produced and purified to obtain F-134a.
Although a was recovered, there was a disadvantage that the distillation separation step was lengthened and energy efficiency was poor.

[0005]

The problem to be solved is that two reactions under different conditions are carried out, and each is separately separated by distillation, which complicates the process and is inefficient.

[0006]

According to the present invention, there is provided a process for producing 1,1,1,2-tetrafluoroethane in which trichloroethylene is reacted with HF, wherein HF and trichloroethylene are reacted in a first reactor to produce 1,1,1,2-tetrafluoroethane. 1,1-trifluoro-
2-Chloroethane and HCl are formed, separated in a second step in a subsequent step, and introduced 1,1,1-trifluoro-
By reacting 2-chloroethane with HF, 1,1,1,2-
The present invention relates to a method for producing 1,1,1,2-tetrafluoroethane in which tetrafluoroethane and HCl are generated, and the reaction gases of both reactors are introduced into one deoxidizing facility to remove HCl.

HF, which is one of the raw materials, can be used either as fresh or separated and introduced in a later step. In addition, as a method for introducing both the reaction gas of the first reactor and the second reactor into one deoxidizing equipment, either a combined system or a single system can be used.

[0008]

FIG. 1 is a view showing one embodiment of a flow of a method for producing F-134a according to the present invention, wherein reference numeral 1 denotes a first reactor,
2 is a second reactor. As a guide for preferable reaction conditions, for example, in the first reactor, pressure: 4 kg / cm ² , temperature: 25
At 0 ° C., the HF / trichlene molar ratio: 6, the pressure in the second reactor is 4 kg / cm ² , the temperature is 350 ° C., and the HF / F-133a molar ratio is 4:

[0009] The reaction products of the first and second reactors 1 and 2 are combined and introduced into the combined reaction product 15 or each alone into one deoxidizing facility 3, where HC contained in both the reaction products is removed.
l is removed. HCl is purified and used for other applications. The other reaction product is the target compound F-13 in the subsequent step.
4a, F-133a and HF. The separated F-133a is supplied as a raw material 14 to the second reactor. HF is the raw material 13 of the first and second reactors.
And 14 are used. In addition, 11 is HF introduced into the system, and 12 is tricrene introduced into the system.

[0010] The device of the present invention has the above-described configuration,
Two reactions under different conditions are carried out, and the reaction products are combined or introduced alone into one deoxidizing facility to remove HCl, whereby F-134a can be efficiently produced with a small number of apparatuses.

Example 1 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 introduced into the deoxidizer were set to 100. Table 1 exemplifies the flow rate of each part in the case.

[0012]

[Table 1]

As is clear from Table 1, by introducing the combined product of the first and second reactors into one deoxidizing facility, by-product HCl can be efficiently removed from the reaction product. Incidentally, reference numeral 15 'in FIG. 1 shows a case where the ink is supplied in a single system. The result is the same as 15.

[0014]

As described above, according to the present invention, the F-
Conventionally, the process for producing 134a has been complicated because the reaction product of each reactor is separately separated by distillation, resulting in inefficiency. On the other hand, the reaction product of two reactions under different conditions is subjected to one deoxidation. Since it is introduced into the facility, the distillation step is simplified, the facility is simplified, and there are advantages such as a reduction in energy consumption.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a flow of a method for producing F-134a of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st reactor 2 2nd reactor 3 Deoxidation equipment 5 Post-process 11 Fresh HF introduced into a system 12 Tricrene introduced into a system 13 Raw material introduced into a 1st reactor 14 To 2nd reactor Raw materials to be introduced 15 Reaction products of both the first and second reactors 16 Distillate distillate 21 Deoxidizer bottom liquid

Continued on the front page (72) Inventor Toshio Oi 5-1 Ogimachi, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture Showa Denko KK Kawasaki Plant (72) Inventor Hidetoshi Nakayama 5-1 Ogimachi, Kawasaki-ku, Kawasaki-shi, Kanagawa Showa Denko KK (56) References JP-A-5-279276 (JP, A) European Patent Application Publication 467531 (EP, A1) (58) Fields investigated (Int. Cl. ⁷ , DB name) C07C 17/38 C07C 17/04 C07C 17/20 C07C 19/08

Claims (1)

(57) [Claims] 1. A process for producing 1,1,1,2-tetrafluoroethane in which trichloroethylene is reacted with HF, wherein HF and trichloroethylene are reacted in a first reactor to produce 1,1,1-trifluoro-ethylene. 2-chloroethane and H
Cl, which is separated in a second step in a second reactor, is introduced 1,1,1-trifluoro-2-chloroethane and H
F, to produce 1,1,1,2-tetrafluoroethane and HCl, and introduce the reaction gas of the first reactor and the second reactor into a deoxidizing facility consisting of one distillation column ,
A method for producing 1,1,1,2-tetrafluoroethane for removing l.