JPH04108743A - Production of pentafluorodichloropropanes - Google Patents

Abstract

PURPOSE:To produce 1,1,1,2,2-pentafluoro-3,3-dichloro- and 1,1,2,2,3- pentafluoro-1,3-dichloropropane by reacting chloroform with difluorochloromethane and tetrafluoroethylene. CONSTITUTION:Chloroform is reacted with difluorochloromethane and tetrafluoroethylene in the presence of a catalyst at -20 to +60 deg.C to produce the title substances in high yield and selectivity. Anhydrous AlCl3 and a compound (e.g. aluminum chlorofluoride or chlorofluorinated alumina) expressed by the formula [(x+y+2z) is 3; 0<x<3; 0<=y<3; 0<=z<3/2, provided that at least either of (y) and (z) is not 0] are preferred as the catalyst. The respective raw materials may be either a gaseous or a liquid state and the title compounds are preferably used as a solvent to carry out the reaction. Since the chloroform will not remain at the time of completing the reaction, difficult separating operation is not required.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to industrially important 1,1,2-trichloro-1,
1.1.1゜2.2-pentafluoro-3,3-dichloropropane (hereinafter referred to as R22
It is called 5ca. ) and 1.1,2°2.3-pentafluoro-1,3-dichloropropane (hereinafter referred to as R225c
Call it b. ).

[Prior Art] Conventionally, as a method for producing R225ca and cb, tetrafluoroethylene (hereinafter referred to as TFE) has been used industrially.

) and dichlorofluoromethane (hereinafter referred to as R-21).
in an autoclave or a glass reaction vessel in the presence of a catalyst such as anhydrous aluminum chloride, in a Hatch method, from 15 to 1
A method of reacting at a temperature of 00°C is known [US Pat. No. 2,462.402, Journal of the American Chemical Society].
or the American Chemical
5ociety), Volume 71, 979L Flexions of Czechoslovak Chemical Communications (Collection of Czechoslovak Chemical Communications)
lovak Chemical Communicat
ions).

Volume 36, 1867].

Furthermore, as a method for producing R225ca, a method is known in which TFE is reacted with cesium fluoride in diglyme and then reacted with chloroform (US Pat. No. 3,381.042).

[Problem to be solved by the invention] However, in the above method using anhydrous aluminum chloride, the selectivity and yield of the target product (46
58%), which is industrially uneconomical. In addition, in order to separate the reaction product from the catalyst after the reaction is completed, the reaction product must be collected in a vacuum-cooled tube or tube, or the reaction product must be separated after treating the catalyst with dilute hydrochloric acid. .

Further, although the reaction using cesium fluoride has good selectivity and yield, the cesium fluoride used as a raw material is very expensive and is not suitable at all for economical industrial production.

[Means for Solving the Problems] The present inventors have studied in detail the manufacturing methods described in the above patents and literature, and have intensively studied new manufacturing methods for R225ca and cb. In place of R-21, which is an essential starting material, chloroform and difluorochloromethane (hereinafter referred to as R-22) were used.
The present inventors have discovered that R-225ca and cb can be obtained with high selectivity and yield when reacted with TFE in the presence of a catalyst, and have completed the present invention.

That is, the gist of the present invention is 1,1,1,2.2- characterized in that chloroform, difluorochloromethane and tetrafluoroethylene are reacted in the presence of a catalyst.
Pentafluoro-3,3-dichloropropane and 1,
A method for producing 1.2,2.3-pentafluoro-1,3-dichloropropane.

As the catalyst used in the present invention, any catalyst can be used as long as it shows activity for the addition reaction of R-21 to TFE, but Lewis acids are preferred, such as anhydrous aluminum chloride, anhydrous titanium tetrachloride, Examples include anhydrous tin tetrachloride, anhydrous antimony pentachloride, anhydrous zinc chloride, anhydrous iron chloride, anhydrous aluminum bromide, and boron trifluoride. Furthermore, the formula: %Formula% [In the formula, xSY and 2 are x+y+2z=3, Q<x
<3, O≦y<3, O≦z<3/2,
At least one of y and Z is not 0. ] Catalysts having the composition shown below, such as chlorinated fluorinated aluminum and chlorinated fluorinated alumina, are also preferably used.

Chlorinated fluoride used as a catalyst in the present invention.

Aluminum chloride is aluminum chloride, hydrogen fluoride,
Hydrofluoric acid, fluorohydrocarbons or chlorofluorohydrocarbons having up to 4 carbon atoms, preferably up to 2 carbon atoms, such as trifluoromethane, tetrafluoroethane, chlorodifluoromethane, dichlorofluoromethane, trifluorodichloroethane, trifluorochloromethane , difluorotetrachloroethane, and trifluorotrichloroethane. At that time, each of them may be allowed to act alone, or may be made to act in combination, or in some cases, may be made to act in combination with a chlorohydrocarbon. The reaction temperature is in the range of 0 to 120°C, preferably 0 to 100°C, and the contact with aluminum chloride may be carried out in a liquid state or in the form of a gas.

The chlorinated fluorinated alumina used as a catalyst in the present invention is produced by reacting activated alumina with a chlorohydrocarbon, a chlorofluorohydrocarbon, a fluorohydrocarbon, hydrogen chloride, or a mixture thereof at a temperature of 100 to 700'C. can be obtained, and is usually obtained as follows. After filling a reaction tube made of stainless steel, Hastelloy, or glass with a specified amount of alumina, the tube is heated to a temperature of 300 to 500° C. under a stream of dry nitrogen to sufficiently dry the alumina. Thereafter, a predetermined temperature is set, usually 100 to 600°C, preferably 200 to 600°C.
It is obtained by flowing a specified fluorocarbon alone or in a mixture with hydrogen chloride gas or oxygen at a temperature of 400° C. for a specified period of time. If the temperature of fluorocarbon treatment is lower than 00°C, the time required for the treatment is too long to be practical, and if it is higher than 600°C, carbon tends to adhere to the alumina surface and the activity tends to decrease. There is. The decrease in activity due to the adhesion of carbon was explained in Japanese Patent Publication No. 61-2737.
As shown in Japanese Patent No. 5, this can be prevented by the coexistence of oxygen or air.

Chlorinated fluorinated alumina can also be obtained by treatment with hydrogen chloride gas as follows. The activated alumina is sufficiently dried by heating to 400 to 800'C under a stream of dry nitrogen. After that, a predetermined temperature, usually 300~
At 700°C, hydrogen chloride gas is passed as it is or diluted with an inert gas such as nitrogen or alcon or a chlorofluorohydrocarbon such as R-12 (dichlorodifluoromethane) or R-21. Typical flow times are 3 to 10 hours.

Any commercially available alumina can be used as long as it is a porous alumina that is usually made of γ-alumina as a main component and is used for dehydration and catalyst purposes. For example, Neobead C, MHR, GB, D (Mizusawa Chemical Industries, Ltd.), activated alumina KHA, NKHI, NKH3 manufactured by Sumitomo Chemical Industries, Ltd., etc. are used.

Chlorohydrocarbons or chlorofluorohydrocarbons, which do not contain hydrogen, have 1 to 3 carbon atoms, preferably 1
-2 are used, particularly preferably carbon tetrachloride,
Fluorotrichloromethane/, difluorochloromethane,
Trifluorochloromethane, 1,1,2-trichloro-
1,2,2-trifluoroethane, 1,1.1-trichloro-2,2°2-trifluoroethane, 1,1,2.
2-tetrafluoro-1,2-dichloroethane, 1.1
, 1.2-tetrafluoro-2,2-dichloroethane,
l.

Examples include 1.2.2-tetrachloro-1,2-difluoroethane and 1.1.1.2-tetrachloro-2,2-difluoroethane. The hydrogen-containing chlorohydrocarbon or chlorofluorohydrocarbon has 1 to 3 carbon atoms, preferably 1 to 2 carbon atoms, particularly preferably fluorodichloromethane, difluorochloromethane, 1.1.1-)refluoro-2,2 -dichloroethane, 1,1.2-1-trifluoro-1°2-dichloroethane, and 1,1.1-trifluoro-2-chloroethane.

In addition, the chlorinated fluorinated alumina catalyst has a temperature of 20 to 450°C.
Hydrogen fluoride at 300-500℃, fluoride 81E yellow (S
F,, SF, etc.), sulfuryl fluoride, thionyl fluoride, ammonium fluoride (acidic ammonium fluoride, neutral), ammonium fluoride, etc.)
It can be produced by reacting with an inorganic fluoride and then reacting with a chlorofluorohydrocarbon, a chlorohydrocarbon, or hydrogen chloride.

Mixtures of two or more of these catalysts may also be used. Among the catalysts used in the present invention, particularly preferred are:
Anhydrous aluminum chloride and the above formula: % formula % [wherein x, y and 2 have the same meanings as above. ] It is a catalyst shown by.

Considering economic efficiency, it is most preferable for the reaction mode used in the present invention to be a reaction mode in which the raw materials are continuously charged and the product is extracted.
A semi-batch method may also be adopted in which the charging is interrupted and the reaction product is extracted after a certain period of reaction.

In the production method of the present invention, the reaction of chloroform, difluorochloromethane and tetrafluoroethylene may be carried out in a solvent.

The type of solvent used is not particularly limited as long as it is inert to the catalyst and dissolves chloroform, R-22 and TFE. For example, chloroform, which is a chloroalkane that is a raw material for this reaction, tetrafluorotrichloropropanes, which is a hydrochlorofluoroalkane, which is a byproduct of this reaction, or general chloroalkanes, such as dichloromethane, may be used. It may be a typical solvent, or it may be tetrachlorotetrafluoropropane, which is a chlorofluoroalkane.

However, in view of ease of reaction operation and separation of raw material chloroform from R-225, the desired product, it is preferable to use R-225 itself.

In the present invention, for example, anhydrous aluminum chloride as a catalyst,
When using R225ca or R-225cb or a mixture of both as a solvent, for example, a predetermined amount of anhydrous aluminum chloride is added to the f! After making V cloudy in the mixture, chloroform, R-22 and TFE are charged at a predetermined temperature and at a predetermined molar ratio and flow rate. R-225ca and cb generated as the reaction progresses
The reaction mixture containing is separated from the suspended anhydrous aluminum chloride and withdrawn from the reaction vessel. Separation from this suspended anhydrous aluminum chloride can be carried out using commonly known methods, e.g.
Separation and extraction in liquid form by filtration and separation and extraction in gaseous form by distillation are used.

The reaction mixture thus obtained is separated and purified by a known method, such as rectification, to obtain the desired R225c.
a and cb can be obtained. The amount of solvent relative to the catalyst should be at least twice the weight of the catalyst; if it is less than that, stirring becomes inefficient and the selectivity of R225ca and cb tends to decrease initially. Therefore, it is undesirable.

The molar ratio of chloroform, R-22 and TFH in the production method of the present invention is 11 or more, preferably 11 to 1:1.
0. The charging molar ratio of R-22 and T F'H is 12 or more, preferably 1:2 to 1°10. The molar ratio of chloroform, R-22 and TFE is, for example, 12:
It is 4.

As for the preparation method, chloroform, R-22 and T
The FEs may be mixed in advance and then added, or they may be added separately at the same time. In some cases, chloroform may be added in a certain amount for a certain period of time, and then a mixed gas of R-22 and TFE may be added. May be used.

Note that each raw material can be charged in either gaseous or liquid form.

The reaction pressure is not particularly limited, and the reaction can be carried out under reduced pressure.

However, since the apparatus becomes complicated, it is preferable to carry out the process at atmospheric pressure or higher.

The reaction temperature is -30 to +1.20°C, preferably -2
The temperature ranges from 0 to +60°C. The reaction temperature is 120
When the temperature is higher than .degree. C., the amount of side reaction products increases, and the selectivity of target R-225ca and cb decreases. Also,
If the reaction temperature is lower than 130°C, the reaction progresses very slowly and is not practical.

Chloroform, the starting material used in the present invention, R-
Both 22 and TFE are manufactured industrially. As the Lewis acid such as anhydrous aluminum chloride, commercially available products can be used as they are.

In the method of the present invention, no chloroform remains at the end of the reaction, so there is no need for difficult roloform separation.

[Effects of the Invention] According to the method of the present invention, R225ca and cb can be obtained in high yield and high selectivity from chloroform, R-22 and TFE. Moreover, it is economical because it can take a continuous reaction form.

[Example] The present invention will be explained below with reference to Examples.

Example 1 15 g of chloroform and 11 g of anhydrous aluminum chloride were placed in a 100 jρ glass flask equipped with a 7 liica gel drying tube and a gas introduction tube to prevent moisture from entering the reaction system.
I prepared g. While stirring with a magnetic stirrer, TFE and R-22 were mixed in advance at a flow rate of 20 cc/min and 10 cc/min, and then charged through a gas introduction tube. At this time, the outside was cooled with ice water to adjust the reaction state to 5 to 10°C. When the reaction solution was analyzed by gas chromatography, chloroform decreased and R225ca and cb increased as the reaction time progressed. 5
After the time reaction, the amount of the reaction solution increased to 51 g, and the composition of the reaction solution at this time was as follows.

Note that chloroform was not detected.

Note: *R-224 represents tetrafluorotrichloropropane.

Example 2 Anhydrous chlorinated fluorinated aluminum was prepared as follows.

After mixing 20 g of anhydrous aluminum mide and 20 g of fluorotrichloromethane, the mixture was stirred at a temperature of 0 to 5° C. for 2 hours, and then the reaction solution was removed under vacuum to obtain anhydrous chlorinated aluminum fluoride. In a reactor similar to Example 1, the anhydrous chlorinated fluoride prepared previously was placed.

2g of aluminum chloride and R225 (ca:cb=5
1:49) 40g was charged. Cool the outside with ice water,
While stirring with a magnetic stirrer and adding chloroform in liquid form at a flow rate of 1.33 g/hour, TFE was added.
and R-22 were mixed in advance at a flow rate of 20 cc/min and 10 cc/min. The weight of the reaction solution after 6 hours had increased to 68 g. The results of analysis after the reaction are shown below. Chloroform was not detected.

Patent applicant: Daikin Industries, Ltd. Representative patent attorney: Haka Aoyama (1 person)

Claims (1)

[Claims] 1. 1,1,1,2,2-pentafluoro-3,3 characterized by reacting chloroform, difluorochloromethane and tetrafluoroethylene in the presence of a catalyst
- A method for producing dichloropropane and 1,1,2,2,3-pentafluoro-1,3-dichloropropane.