JP2738042B2 - Method for producing 3,3-dichloro-1,1,1,2,2-pentafluoropropane - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for producing 3,3-dichloro-1,1,1,2,2-pentafluoropropane (R225ca). Hydrogen-containing chlorofluoropropanes are expected to be used as blowing agents, refrigerants, detergents, and the like, similarly to conventionally used fluorocarbons.

[Prior Art and Problems to be Solved by the Invention] As a method for producing R225ca, a method of synthesizing by adding dichlorofluoromethane to tetrafluoroethylene in the presence of aluminum chloride is conventionally known. However, this method produces a reaction by-product which has a boiling point close to that of the target product at the same time as the target product and is difficult to separate by ordinary methods such as distillation, so that a multi-stage purification step is required to obtain a product of high purity. Has disadvantages.

[Means for Solving the Problems] The present inventors have conducted intensive studies on an efficient method for producing 3,3-dichloro-1,1,1,2,2-pentafluoropropane (R225ca), and as a result, Trichlorofluoromethane (R11) is added to fluoroethylene to produce 1,1,1-trichloropentafluoropropane (R215cb), which is then reduced to give a high yield.
The inventors have found that 3,3-dichloro-1,1,1,2,2-pentafluoropropane (R225ca) can be obtained, and have provided the present invention.

 Hereinafter, details of the present invention will be described together with examples.

That is, when tetrachloroethylene (4F) is added with trichlorofluoromethane (R11) in an inert solvent or in the absence of a solvent in the presence of a Lewis acid catalyst, 1,1,1-trichloro- 2,2,3,3,3-pentafluoropropane (R215cb) Is obtained in high yield. Examples of the Lewis acid catalyst used in the addition reaction include chloride, fluoride, and bromide containing at least one element selected from the group consisting of B, Al, Fe, Ni, Co, Sb, Nb, Sn, Ti, and Ta. And the like can be used. When a solvent is used for the reaction, an inert solvent such as perfluorooctane or perfluorobutyltetrahydrofuran is suitable, but in order to facilitate purification, it is usually particularly preferable to perform the reaction without a solvent.

The reaction temperature and reaction time are -50 to 100 ° C for the liquid phase,
1 to 10 hours, preferably -10 to 400 ° C, 3 to 6 hours, and in the case of a gas phase, 60 to 300 ° C, 0.1 to 300 sec, preferably 100 to 2 hours.
50 ° C. and 1 to 30 seconds are appropriate. The reaction can be carried out at normal pressure or under pressure, and the reaction molar ratio is such that R-11 is
1.0 to 1.5 mol is appropriate.

The reduction of 1,1,1-trichloropentafluoropropane (R215cb) obtained by the addition reaction can be performed by various methods such as a method using light irradiation, a method using zinc, and a method using hydrogen in the presence of a catalyst. It can be performed using a method. When the reduction is performed under light irradiation, the compound used as a proton source is not particularly limited as long as it is an organic compound to which a hydrogen atom is bonded.
Alcohols such as ethanol, isopropyl alcohol and sec-butyl alcohol, alkanes such as hexane and heptane, aromatic compounds such as toluene and xylene are preferable, and secondary alcohols such as isopropyl alcohol are particularly preferable. These mixed solvents can also be used. The solvent used in the reduction using zinc is not particularly limited as long as it is an organic compound to which a hydrogen atom is bonded, but may be methanol, ethanol, alcohols such as isopropyl alcohol, organic acids such as acetic acid and formic acid, and tetrahydrofuran. It is preferable to use ethers, water, and mixtures thereof, and it is particularly preferable to use alcohols such as methanol, ethanol, and isopropyl alcohol.

When the reduction is carried out using hydrogen in the presence of a catalyst, any of a liquid phase and a gas phase can be used. As the reduction catalyst, any of a noble metal catalyst such as platinum, palladium, rhodium and ruthenium and a base metal catalyst such as nickel can be used, and among them, an acid-resistant noble metal catalyst is particularly preferable.
It is preferable that these catalysts are supported on a carrier such as activated carbon or alumina because the catalyst activity and life are improved. When the reduction is performed in the liquid phase, the reduction may be performed without a solvent, or a solvent inert to the reaction, for example, an alcohol such as methanol, ethanol, or isopropyl alcohol may be used.

The reduction reaction temperature and reaction time are 25 to 150 for the liquid phase.
° C, 0.1 to 10 min, preferably 40 to 100 ° C, 1 to 5 min, and in the case of a gas phase, 60 to 300 ° C, 0.1 to 300 sec, preferably
100-250 ° C and 1-30 sec are appropriate. The reaction can be carried out under normal pressure or under pressure, and the reaction molar ratio is as follows. ,
When zinc is used in an amount of about 1 to 2 moles per 1 mole of R215cb, about 1 to 2 times the stoichiometric amount of the organic compound to which a hydrogen atom is bonded is appropriate for 1 mole of R215cb.

EXAMPLES Examples of the present invention will be described below.

Example 1 Anhydrous aluminum chloride was added to a 10 Hastelloy C autoclave.
After adding 0.5 kg (3.7 mol) of minium and degassing under reduced pressure, R11
Was added in an amount of 5 kg (36.4 mol). Autoclave cooled to 0 ° C
After that, while maintaining the reaction temperature at 10-20 ° C,
Continued addition of ethylene. 4k of tetrafluoroethylene
After adding g (40 mol), stirring was continued for another hour and the reaction solution was filtered.
Separately, the reaction crude liquid is purified by distillation to give R 215cb
6.1 kg was obtained (yield 71%). Then 2.54 cm inside diameter, length 100
Activated carbon loaded platinum in a cm-shaped Inconel 600 U-shaped reaction tube
Filling 100 ml of catalyst (loading rate 0.5%) to make a reduction reactor,
The reactor was kept at 120 ° C. Gasified R 215
The reaction was carried out by supplying cb at 96 ml / min and hydrogen gas at 144 ml / min.
I did. After removing the acid content, the trap was cooled to -78 ° C.
4.5 kg of the crude liquid was recovered and analyzed by gas chromatography and 19F-NMR.
Was analyzed. The results are shown in Table 1.

By distilling and purifying the reaction crude liquid, R 225ca was changed to 3.6
kg (68% yield).

Example 2 0.5 kg (3.7 mol) of anhydrous aluminum chloride was added to an autoclave made of Hastelloy C of No. 10 and degassed under reduced pressure.
Was added in an amount of 5 kg (36.4 mol). After cooling the autoclave to 0 ° C, tetrafluoroethylene was continuously added while maintaining the reaction temperature at 10 to 20 ° C. 4k of tetrafluoroethylene
After adding g (40 mol), the mixture was further stirred for 1 hour, the reaction solution was separated by filtration, and the crude reaction solution was purified by distillation to obtain R215cb.
6.1 kg was obtained (yield 71%). Then, 2,000 g (6 mol) of methanol, 300 g of zinc dust,
g (4.6 mol), and while stirring at 0 ° C., add R 215cb to 10
00 g (4.2 mol) was added dropwise. After completion of the dropwise addition, stirring was further continued at 0 ° C. for 8 hours, and the reaction solution was washed with 2N aqueous hydrochloric acid. Organic layer 90
0 g was recovered and analyzed using gas chromatography and 19F-NMR. The results are shown in Table 2.

By distilling and purifying the reaction crude liquid, R 225ca is increased to 350
g (yield 41%).

[Effects of the Invention] As shown in the examples, the present invention provides 3,3-dichloro-1,1,1,2,2-pentafluoropropane (R 225ca), for which it was conventionally difficult to obtain high-purity products. Can be produced in high yield.

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Toshihiro Tanuma 2-24-31 Konan-ku, Konan-ku, Yokohama-shi, Kanagawa

Claims (4)

(57) [Claims] 1. A process for producing 1,1,1-trichloropentafluoropropane by adding trichlorofluoromethane to tetrafluoroethylene, followed by a reduction reaction of 3,3-dichloro-1. For producing 1,1,1,2,2-pentafluoropropane. 2. The method according to claim 1, wherein the reaction of adding 1, chlorotrifluoromethane to tetrafluoroethylene to form 1,1,1-trichloropentafluoropropane is performed in the presence of a Lewis acid catalyst. 3. The production method according to claim 1, wherein the reduction reaction is carried out using hydrogen in the presence of a reduction catalyst. 4. The method according to claim 1, wherein the reduction reaction is carried out in the presence of zinc using an organic compound to which a hydrogen atom is bonded.