JPH11140002A - Production of 1,3,3,3-tetrafluoropropene - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject compound in a high yield, by passing a specific pentafluoropropane to a reaction zone in a vapor phase at a raised temperature. SOLUTION: 1,1,1,3,3-Pentafluoropropane is introduced to a reaction zone in a vapor phase at a raised temperature in a reactor made of a material substantially inert to hydrogen fluoride. The reaction temperature is preferably 200-600 deg.C and the reaction pressure is 0.1-10 kg/cm<2> and the contact time is preferably 0.1-300 seconds generally. Preferably activated carbon or activated carbon carrying 0.1-80 wt.% calculated as a metal supplied amount of a metal compound such as chromium compound or the like is preferably used as a catalyst.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a process for producing 1,3,3,3-tetrafluoropropene useful as a reagent for introducing a trifluoromethyl group, an intermediate material for medicines and agrochemicals, polymers, functional materials or as a refrigerant. About.

[0002]

2. Description of the Related Art As a method for producing 1,3,3,3-tetrafluoropropene, conventionally, 1,3,3,3-tetrafluoro-1-propane iodide is dehydroiodated with alcoholic potassium hydroxide. Method (RN Hasze)
ldine et al. Chem. Soc. 1953, 11
99-4206; CA 48 5787f) or a method of dehydrofluorinating 1,1,1,3,3-pentafluoropropane with potassium hydroxide in dibutyl ether (IL Kunyanants et al., Izvest.
Akad. Nauk S.D. S. S. R. , Otdel.
Khim. Nauk. 1960, 1412-18; CA
55, 349f) and the like are known.

[0003] Further, as a method for producing fluorinated propene by dehydrofluorination from fluorinated propane, there are two methods:
Heat 2-difluoropropane to 731 ° C. to give 1
Method for producing t-fluoropropene (Austin et al.,
J. Am. Chem. Soc 75 [1953] 4834), 1,1,1-trifluoropropane was heated to 830 to 850 ° C.
-Method for producing difluoropropene (Kinetic Chemic
al. Inc., USP2480560 [1945]).

[0004]

The above-mentioned method of dehydrohalogenating with potassium hydroxide is excellent in the reaction rate and selectivity, but requires a stoichiometric amount of potassium hydroxide. And the raw materials 1,3
3,3-Tetrafluoro-1-propane iodide must be prepared in advance, and there are many difficulties for industrial application.

[0005] On the other hand, the method using dehydrofluorination does not require a reaction reagent other than the raw material, and is industrially preferable. However, there is a problem that a high temperature of 700 ° C or more is required as described above.

[0006]

SUMMARY OF THE INVENTION The present inventors have made 1,3,3 a starting material which can be obtained on an industrial scale or which can be relatively easily produced from raw materials available on an industrial scale. A study was conducted on a method for producing 1,3,3-tetrafluoropropene. As a result, 1,1,1,3,3-pentafluoropropene was used as a raw material, and the temperature was raised to a specific temperature or higher in a gaseous phase. , 3-tetrafluoropropene was obtained, and it was also found that it is particularly preferable to use activated carbon or activated carbon carrying a metal compound such as a chromium compound as a catalyst, and have reached the present invention.

That is, the present invention relates to 1,1,1,3,3
A process for producing 1,3,3,3-tetrafluoropropene, which comprises passing pentafluoropropane in a gas phase to a reaction zone at an elevated temperature.

[0008] The method for producing 1,1,1,3,3-pentafluoropropane used in the present invention is not particularly limited.
For example, propane represented by the general formula CF _Y Cl _3-Y CH ₂ CHF _W Cl _2-W (where W represents 0 or 1, and Y represents an integer of 0 to 3) in the presence of a catalyst. A method of fluorinating with hydrogen fluoride in a liquid phase, particularly a method of producing 1,1,1,3,3-pentachloropropane by liquid-phase fluorination with hydrogen fluoride, wherein an antimony compound is used as a catalyst Or 1,1,1,3,3-pentachloropropane or 1-chloro-3,3,3-trifluoropropene produced by a method of fluorinating with hydrogen fluoride in the gas phase in the presence of a chromium catalyst. Can be mentioned.

The process of the present invention comprises the steps of: adding 1,1,1,3,3-pentafluoropropane to an elevated temperature reaction zone of a reactor made of a material substantially inert to hydrogen fluoride. It is done by introducing. The container is usually tubular and made of stainless steel, Hastelloy, Monel, platinum, carbon or a material lined with these. The reactor may be hollow or may have various shapes of fillers made of a material that is substantially inert to hydrogen fluoride. Fillers include platinum, nickel, gold,
Silver, carbon and the like are used, and those made of carbon are particularly preferable. The carbon used as the filler is usually activated carbon, and is a plant based on wood, sawdust, charcoal, coconut husk charcoal, palm kernel charcoal, ash, etc., peat, lignite, lignite, bituminous, anthracite And the like, and petroleum based on petroleum residue, sulfuric acid sludge, oil carbon or the like as a raw material or synthetic resin as a raw material. Since various types of such activated carbons are commercially available, they may be selected and used. For example, activated carbon produced from bituminous coal (for example, granular activated carbon C
AL (manufactured by Toyo Calgon Co., Ltd.), coconut shell charcoal (eg, manufactured by Takeda Pharmaceutical Co., Ltd.) and the like can be cited, but are not limited to these types and manufacturers. These activated carbons are usually used in the form of granules, but their shape and size are not particularly limited, and can be determined based on the size of the reactor with ordinary knowledge.

[0010] The activated carbon may be an oxide, a fluoride of one or more metals selected from aluminum, chromium, manganese, nickel, cobalt and titanium.
Activated carbon carrying chloride, fluoride chloride, oxyfluoride, oxychloride, oxyfluoride chloride or the like may be used.

The method of preparing these metal-supported activated carbon catalysts is not limited, but chromium, titanium, manganese can be added to activated carbon as it is or to activated carbon previously modified with halogen such as hydrogen fluoride, hydrogen chloride, or chlorinated fluorinated hydrocarbon. One or two selected from nickel, nickel and cobalt
It is prepared by impregnating or spraying a solution of a soluble compound of one or more metals.

The amount of the metal carried is 0.1 to 80% by weight, preferably 1 to 40% by weight. Examples of the soluble compound of the metal supported on the activated carbon include nitrates, chlorides and oxides of the metal dissolved in a solvent such as water, ethanol and acetone. Specifically, chromium nitrate, chromium trichloride, chromium trioxide, potassium dichromate, titanium trichloride, manganese nitrate, manganese chloride, manganese dioxide, nickel nitrate, nickel chloride, cobalt nitrate, cobalt chloride, etc. may be used. it can.

[0013] The catalyst supporting the metal by any method is treated with a fluorinating agent such as hydrogen fluoride or fluorinated (and chlorinated) hydrocarbon at a temperature higher than a predetermined reaction temperature before use. It is effective to prevent a change in the composition of the catalyst inside. Supplying oxygen, chlorine, fluorinated or chlorinated hydrocarbons, etc. into the reactor during the reaction is effective for extending the life of the catalyst, improving the reaction rate, and improving the reaction yield.

The reaction temperature of the process according to the invention is between 200 and 600.
C., preferably 250-500.degree.
If it is lower than 0 ° C., the reaction is slow and not practical. If the reaction temperature exceeds 600 ° C., the reaction rate is not particularly improved, and decomposition products and dimers are formed, and the selectivity of 1,3,3,3-tetrafluoropropene decreases, which is not preferable.

In the method of the present invention, the 1,1,1,3,3-pentafluoropropane supplied to the reaction zone may be supplied simultaneously with an inert gas such as nitrogen, helium or argon. Further, hydrogen fluoride may be allowed to coexist.

The reaction pressure is not particularly limited, but is preferably 0.1 to 10 kg / cm ² from the viewpoint of the apparatus. It is desirable to select conditions so that the raw material organic matter and hydrogen fluoride present in the system do not liquefy in the reaction system. The contact time is usually 0.1 to 300 seconds, preferably 5 to 200 seconds.

The product containing 1,3,3,3-tetrafluoropropene which is treated by the method of the present invention and flows out of the reactor is purified by a known method to obtain a product. The purification method is not limited. For example, the product is first washed with water or / and an alkaline solution to remove acidic substances such as hydrogen chloride and hydrogen fluoride, and after drying, subjected to distillation to remove organic impurities. It can be done by removing.

In the process of the present invention, the product 1,
3,3,3-Tetrafluoropropene can be obtained as a mixture of a trans form and a cis form, and the cis form is 1,1,
The boiling point is close to that of 1,1,3,3-pentafluoropropane, and it exhibits an azeotropic behavior, so that it cannot be easily separated. Thus, trans and cis forms of 1,3,3,3-tetrafluoropropene and 1,1,1,3,3-
The mixture (product) consisting of pentafluoropropane was distilled to recover only the trans form, and the remaining cis form and 1,1
Without separating 1,1,3,3-pentafluoropropane, it can be used again for the reaction of the present invention. In other words, the cis-isomer, which is difficult to separate and recover, is not deliberately separated, but is recovered as a trans-isomer, so that 1,3,
3,3-tetrafluoropropene can be produced.

[0019]

EXAMPLES [Preparation Example 1] 300 g of a special grade reagent Cr (NO
₃₎ the ₃ · 9H ₂ O to a solution of pure water 1 liter,
Diameter 4-6 mm, surface area 1200 m ² / g, pore size 18
A granular activated carbon (Takeda Pharmaceutical Co., Ltd., granular Shirasagi GX) 1.8
Liters were immersed and left overnight. Next, the activated carbon was filtered out and kept at 100 ° C. in a hot-air circulation dryer.
It was dried all day and night. The obtained chromium-supported activated carbon was filled into a cylindrical SUS316L reaction tube having a diameter of 3.5 cm and a length of 150 cm equipped with a heating device, and heated to 300 ° C. while flowing a nitrogen gas. At this time, the concentration of hydrogen fluoride was gradually increased by entraining hydrogen gas into the nitrogen gas, the reactor temperature was raised to 350 ° C., and the state was maintained for 1 hour to prepare a catalyst. [Example 1] A gas phase reactor (made of SUS316L, having a diameter of 2.5) comprising a cylindrical reaction tube heated by an external heater.
cm./length 40 cm) was filled with 150 ml of the catalyst prepared in Preparation Example 1 as a gas phase fluorination catalyst. About 5
The temperature of the reaction tube was raised to 380 ° C. while flowing nitrogen gas at a flow rate of 0 ml / min, and hydrogen fluoride was continuously introduced at a rate of about 0.3 g / min for 1 hour. The introduction of hydrogen fluoride was stopped, the flow rate of nitrogen gas was reduced to 20 ml / min, and 1,1,1,3,3-pentafluoropropene was vaporized as a raw material organic material in advance and reacted at a rate of 0.44 g / min. Supply to the vessel started.

One hour after the start of the reaction, the reaction was stable. The product gas discharged from the reactor was blown into water to remove acidic gas, and then collected by a dry ice-acetone trap. The results of analyzing the collected organic matter by gas chromatography are shown in Table 1.

[0021]

[Table 1]

Example 2 A gas phase reactor (SUS316L) comprising a cylindrical reaction tube heated by an external heater
(Diameter: 2.5 cm, length: 40 cm) was charged with 150 ml of the catalyst prepared in Preparation Example 1 as a gas phase fluorination catalyst. The temperature of the reaction tube was raised to 380 ° C. while flowing nitrogen gas at a flow rate of about 50 ml / min, and about 0.2 ml of hydrogen fluoride was added.
The introduction was continued at a rate of 3 g / min for 1 hour. Next, the temperature of the reaction tube was lowered to 350 ° C., the supply of hydrogen fluoride was stopped, the flow rate of nitrogen gas was reduced to 20 ml / min, and 1,1,1,3,3-pentafluoropropane was previously used as a raw material organic substance. It was vaporized and started feeding to the reactor at a rate of 0.48 g / min.

Since the reaction was stable one hour after the start of the reaction, the product gas flowing out of the reactor was blown into water to remove the acidic gas, and then collected with a dry ice-acetone trap. The results of analyzing the collected organic matter by gas chromatography are shown in Table 1.

Example 3 A reaction was carried out in the same manner as in Example 2 except that 1,1,1,3,3-pentafluoropropane was reacted at a reaction temperature of 300 ° C. Table 1 shows the results.

Example 4 A gas phase reactor (SUS316L) comprising a cylindrical reaction tube heated by an external heater
(Diameter: 2.5 cm, length: 40 cm) was charged with 150 ml of the catalyst prepared in Preparation Example 1 as a gas phase fluorination catalyst. The temperature of the reaction tube was raised to 380 ° C. while flowing nitrogen gas at a flow rate of about 150 ml / min, and hydrogen fluoride was continuously introduced at a rate of about 0.28 g / min for 1 hour.
Reduce the temperature of the reaction tube to 255 ° C.,
With the flow rate of the nitrogen gas kept as it was, 1,1,1,3,3-pentafluoropropane was vaporized in advance as a raw material organic substance, and supply to the reactor was started at a rate of 0.21 g / min.

One hour after the start of the reaction, the reaction was stable. The product gas discharged from the reactor was blown into water to remove the acidic gas, and then collected with a dry ice-acetone trap. The results of analyzing the collected organic matter by gas chromatography are shown in Table 1.

[0027]

According to the process for producing 1,3,3,3-tetrafluoropropene of the present invention, 1,1,1,3,3-pentafluoropropane is used as a raw material and 3-
Since tetrafluoropropene can be produced, it is useful as an industrial production method.

Claims (3)

[Claims] 1. A process for producing 1,3,3,3-tetrafluoropropene, which comprises passing 1,1,1,3,3-pentafluoropropane in a gas phase to a reaction zone at an elevated temperature. 2. The method for producing 1,3,3,3-tetrafluoropropene according to claim 1, wherein the reaction region is carbon or carbon carrying a metal compound. 3. The 1,3,3,3-tetrafluoropropene according to claim 1, wherein the 1,3,3,3-tetrafluoropropene is a 1,3,3,3-tetrafluoropropene comprising a trans form and a cis form.
A method for producing 3,3-tetrafluoropropene.