JPH03127746A - Production of dichloropentafluoropropane - Google Patents

Abstract

PURPOSE:To obtain the title compound expected to be useful as blowing agent, refrigerant, detergent, etc., in high yield by adding trichlorofluoromethane to tetrafluoroethylene to give trichloropentafluoropropane and then reducing. CONSTITUTION:Trichlorofluoromethane shown by formula II is added to tetrafluoroethylene shown by formula I in the presence of a Lewis acid in an inert solvent or in a solventless state to form trichloropentafluoropropane shown by formula III and formula IV, which is reduced by light irradiation method, a method of using zinc or a method of using hydrogen in the presence of a catalyst to give 3,3-dichloro-1,1,1,2,2-pentafluoropropane (R225ca) and 1,3- dichloro-1,1,2,2,3-pentafluoropropane (R225cb), especially high-purity R225ca, which has been difficult to obtain, in high yield.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention provides 3,3-dichloro-1,1,1,2,2-pentafluoropropane (R225ca) and 1,3-
The present invention relates to a method for producing dichloro-1,1,2,2,3-pentafluoropropane (R225cb). Similar to conventionally used fluorocarbons, hydrogen-containing chlorofluoropropanes are expected to be used as blowing agents, refrigerants, cleaning agents, etc.

[Prior art and problems to be solved by the invention] 3.3
-Production method of dichloro-1,1,1,2,2-pentafluoropropane (R225ca) and 1,3-dichloro-1,1,2,2,3-pentafluoropropane (R2
As for 25cb), a conventional method is known in which it is synthesized by adding dichlorofluoromethane to tetrafluoroethylene in the presence of aluminum chloride. However, this method requires multiple purification steps to obtain a highly pure product, as it is difficult to separate the desired product using normal methods such as distillation because the boiling point is close to that of the desired product, and reaction by-products such as loloform are produced. It has the disadvantage of being

[Means for Solving the Problems] As a result of extensive research into an efficient method for producing 3,3-dichloro-1,1,1,2,2-pentafluoropropane (R225ca), the inventors found that tetrafluoropropane Trichlorofluoromethane (R11) is added to ethylene to produce 1,1,1-trichloropentafluoropropane (
R215cb) and 1,1,3-trichloropentafluoropropane (R215ca) are then reduced to produce 3,3-dichloro-1,1,1,2,2- in high yield. Pentafluoropropane (
R225ca) and 1,3-dichloro-1,1,2,
The present inventors have discovered that 2,3-pentafluoropropane (R225cb) can be obtained and have provided the present invention. R225Ca and R2 obtained by the present invention
25cb can be separated and purified by distillation, but of course it can also be used as a solvent, detergent, etc. as a mixture.

The details of the present invention will be explained below along with examples.

That is, when trichlorofluoromethane (R11) is subjected to an addition reaction to tetrafluoroethylene in an inert solvent or without a solvent in the presence of a Lewis acid catalyst, 1.1.1-trichloro-22333-penta Fluoropropane (R215cb) CF2= CF2 + CG13F Lewis acid catalyst CF3CF2CCl3+C;C;lF2C
F2CC1,F and 113-trichloropentafluoropropane (R215ca) are obtained in high yield.

The Lewis acid catalyst used in this reaction is BAI Ga
In Fe Ni Co Sb Nb,
A halide containing at least one element selected from the group consisting of Sn, TiZr, W and Ta, for example BF3. AlCl3. GaCl3. InCl3
．． FeC↓a, Ni, C1,2CoC12SbF
s NbCl5.5nC1, TiC1,, ZrC:L
WCl, TaClg, etc. can be used. Although the reaction is preferably carried out using an inert solvent such as perfluorooctane or perfluorobutyltetrahydrofuran, it is usually particularly preferable to carry out the reaction without a solvent in order to facilitate purification. The amount of catalyst is usually 0. Ol ~ 50% by weight
, preferably 0.1 to 10% by weight. The reaction temperature is usually -80 DEG to 200 DEG C., preferably -20 DEG to 100 DEG C., and the reaction pressure is suitably 0 to 20 kg, 7 cm@2, particularly preferably 0 to 10 kg, 70 m@2. R
The production ratio of 215cb and R215ca depends on the catalyst used,
It can vary depending on reaction conditions.

The reduction of 1,1,1-trichloropentafluoropropane (R215cb) and 113-trichloropentafluoropropane (R215ca) obtained by this reaction can be carried out under light irradiation, using zinc, or in the presence of a catalyst. It can be carried out using various reduction methods such as a method using hydrogen. When the reduction is carried out under light irradiation, the compound used as a proton source is not particularly limited as long as it is an organic compound containing a hydrogen atom, but examples include alcohols such as methanol, ethanol, isopropyl alcohol, and 5ee-butyl alcohol, hexane, Alkanes such as heptane, aromatic compounds such as toluene and xylene are preferred, and secondary alcohols such as isopropyl alcohol are particularly preferred. A mixed solvent of these may also be used.

The light source used in the present invention is not particularly limited as long as it emits light with a wavelength of 400 nm or less, but for example,
High-pressure mercury lamps, medium-pressure mercury lamps, low-pressure mercury lamps, etc. are preferred.

The reaction is usually carried out at a temperature range of -80 to 100°C, preferably 0 to 40°C. The pressure is also not particularly limited, but is usually 0-10 kg/cm2, preferably 0-2 kg/cm2.
It is best to perform this in a pressure range of cm2G.

Solvents used for reduction using zinc include, but are not particularly limited to, alcohols such as methanol, ethanol, and isopropyl alcohol, organic acids such as acetic acid and formic acid, ethers such as tetrahydrofuran, water, and mixtures thereof. It is preferable to use alcohols such as methanol, ethanol, and isopropyl alcohol. Zinc may be in any form such as powder, granules, or scraped pieces, but it is most preferable to use zinc powder. Further, there is no need to perform any special activation treatment before use. The amount of zinc used is not particularly limited, but it is usually preferable to use it in an amount equal to or more than the equivalent mole based on the starting material.

The reaction is usually carried out at room temperature to 150°C, preferably 50 to 80°C.
It is carried out in the temperature range of °C. The pressure is also not particularly limited, but is usually O~lokg/am2, preferably 0~3k
It is preferable to perform this in a pressure range of g/cm2G.

When the reduction is carried out using hydrogen in the presence of a catalyst, either a liquid phase or a gas phase system can be adopted. As the reduction catalyst, any of noble metal catalysts such as platinum, palladium, rhodium, and ruthenium, and nonmetal catalysts such as nickel can be used, but it is particularly preferable to use noble metal catalysts. As the carrier for the reduction catalyst, for example, alumina, activated carbon, etc. are suitable. As the supporting method, a conventional noble metal catalyst preparation method can be applied. In addition, in order to obtain stable characteristics, it is preferable to subject the catalyst to a reduction treatment in advance before use, but this is not always necessary. Compounds of such metals are at least partially reduced.

The proportions of hydrogen and feedstock can be varied widely. Usually, a stoichiometric amount of hydrogen is used to remove the halogen atoms, but in order to almost completely react the raw materials, an amount significantly greater than the stoichiometric amount, e.g. 4 times the mole, relative to the total moles of starting material. or more hydrogen may be used.

In the gas phase reaction, the reaction temperature is suitably 100 to 350°C, and particularly preferably 100 to 200°C. The contact time is usually 0.1 to 300 seconds, preferably 2 to 60 seconds. Examples of solvents used when carrying out the reaction in a liquid phase include alcohols such as ethanol and isopropyl alcohol, acetic acid, and pyridine, but it is also possible to carry out the reaction without a solvent. The reaction temperature in liquid phase reaction is room temperature to 150℃.
℃ is preferable, and the reaction pressure is normal pressure to 100 kg/cm
2 is preferred.

As described above, the present invention adds trichlorofluoromethane (R11) to tetrafluoroethylene to obtain 1,1.
1-Trichloropentafluoropropane (R215cb
)J and 1,1.3-)dichloropentafluoropropane (R215ca), and then reducing it to produce 3.3-dichloro-1,1 in high yield.
, 1,2,2-pentafluoropropane (R225c
a) and 1,3-dichloro-1,l, 2.2.3-
A method for producing pentafluoropropane (R225cb) is provided.

[Example] Examples of the present invention will be shown below.

Example 1 After adding 0.05 kg (0.37 mol) of anhydrous aluminum chloride to a Hastelloy C autoclave at 10°C and degassing under reduced pressure, Rl 1 (CG12F) 5
kg (36.4 mol) was added. After cooling the autoclave to 0°C, tetrafluoroethylene was continued to be added while maintaining the reaction temperature at 10-20°C. After adding 4 kg (40 mol) of tetrafluoroethylene, the mixture was further stirred for 1 hour, and then the reaction solution was filtered, and the crude reaction solution was purified by distillation to obtain R215cb (1,1,1-trichloropentafluoropropane) and R215ca
7.6 kg of a mixture of (1,1,3-trichloropentafluoropropane) was obtained (yield 88%), R215cb
The production ratio of R215ca and R215ca was 87:13. Next, the inner diameter is 2.54 cm.

100 ml of platinum catalyst supported on activated carbon (support rate 0.5%) in a U-shaped reaction tube made of Inconel 600 with a length of 100 cm
was filled to form a reduction reactor, and the reactor was maintained at 150°C. R215cb and R215c gasified into this
96 m1/min of the mixture a, 144 m17 of hydrogen gas
The reaction was allowed to proceed. After removing acid content -78℃
5.7 kg of the reaction crude liquid was collected in a trap cooled to 100 mL and analyzed using gas chromatography and 19F-NMR. The results are shown in Table 1.

By distilling and purifying the reaction crude liquid in Table 1, R225ca (3
,3-dichloro-1,1,l,2,2-pentafluoropropane) and R225cb(1,3-dichloro-
4.7 kg of a mixture of 1,1,2,2,3-pentafluoropropane was obtained (yield 72%).

Example 2 0.5 kg (2.6 mol) of titanium tetrachloride was added to a 1042 Hastelloy C autoclave in a nitrogen stream, and 5 kg (36.4 mol) of R11 (CG13F) was added.
) was added. After heating the autoclave to 40℃,
Tetrafluoroethylene was continued to be added while maintaining the reaction temperature at 40-50°C. Tetrafluoroethylene 4k
After adding g (40 mol), the reaction mixture was stirred for an additional hour, and the organic layer was purified by distillation to obtain R.
215c b (1,1,1,-1□lichlorobentafluoropropane) and R215ca (1,1,3-1
-'J chloropentafluoropropane) mixture
．． 2 kg was obtained (yield 84%). R215cb and R2
The production ratio of 15ca was 53:47. Then inner diameter 2
．． A platinum catalyst supported on activated carbon (supporting rate 0.5%) was placed in a U-shaped reaction tube made of Inconel 600 with a length of 54 cm and a length of 100 cm.
) Fill 100ml to form a reduction reactor, and reduce the reactor to 1
It was maintained at 70°C. A gasified mixture of R215cb and R215ca was supplied to the reactor at a rate of 96 ml/min, and hydrogen gas was supplied at a rate of 144 ml/min to proceed with the reaction. After removing the acid content, 5.6k of the crude reaction liquid was placed in a trap cooled to -78°C.
g was collected and analyzed using gas chromatography and 19F-NMR. The results are shown in Table 2.

By distilling and purifying the reaction crude liquid in Table 2, R225ca (3
,3-dichloro-1,1,1,2,2-pentafluoropropane) and R225cb (1,3-dichloro-1
, 1,2,2,3-pentafluoropropane) was obtained (yield: 69%).

[Effects of the Invention] As shown in the examples, the present invention enables high yield of high-purity 3,3-dichloro-1,1,1,2,2-pentafluoropropane (R225ca), which has been difficult to obtain in the past. It has the advantage that it can be manufactured at a high rate.

Claims (1)

[Claims] 3,3-dichloro-1,1,1,2,2-pentafluoropropane, which is characterized in that trichlorofluoromethane is added to tetrafluoroethylene to produce trichloropentafluoropropane, and then this is reduced. and 1,3-dichloro-1,1,2,2,
Method for producing 3-pentafluoropropane.