JPH0753420A - Method for dimerizing chlorofluorinated ethane - Google Patents

Abstract

PURPOSE:To provide an industrial and advantageous method for dimerizing a chlorofluorinated ethane at a high rate of reaction in high selectivity with a long life in producing the dimer of the chlorofluorinated ethane. CONSTITUTION:The characteristic of this method for dimerizing a chlorofluorinated ethane comprises using a catalyst consisting essentially of ruthenium. When 1,1,1-trichloro-2,2,2trifluoroethane is used as a representative raw material, 2,3-dichloro-1,1,1,4,4,4-hexafluorobutene-2 is obtained as a principal product.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing a dimer of chlorinated fluorinated ethane.

[0002]

2. Description of the Related Art 2,3-Dichloro-containing compound as a raw material for producing 1,1,1,4,4,4-hexafluorobutane useful as a foaming agent for polyolefin, polystyrene, polyurethane, polyisocyanurate, etc. 1, 1,
1,4,4,4- chlorinated fluorinated C ₄ hydrocarbons such as hexafluoro-2-ene has been proposed.

Known methods for producing chlorinated fluorinated C ₄ hydrocarbons include fluorination of chlorinated butenes, reaction of fluorinated propene with chlorinated methane, and dimerization of chlorinated fluorinated ethane. Has been.

2,3-dichloro-1,1,1,4,4,4
Regarding 4-hexafluorobutene-2, perfluorobutadiene fluorination (USP2436357) and 1,1,1-trichloro-2,2,2-trifluoroethane dimerization using a nickel catalyst (JP-A-4-264).
No. 040) has been proposed.

However, the former method has low selectivity and low yield. The latter method is not always preferable as an industrial production method because of its low selectivity, short catalyst life, and easy powdering because silica is used as a carrier.

[0006]

In order to solve the above-mentioned problems, the present inventors have proposed a method for obtaining a dimer of chlorinated fluorinated ethane by using a corresponding chlorinated fluorinated ethane as a raw material in the presence of a catalyst. As a result of diligent studies on a method for producing a dimer by a chlorine dimerization reaction, when a chlorinated fluorinated ethane was dechlorinated and dimerized using a catalyst containing ruthenium as a main component, a good yield and a selective purpose were obtained. The present invention has been achieved by finding that a dimer of

That is, the present invention is a method for producing chlorinated fluorinated C ₄ hydrocarbons by dimerizing chlorinated fluorinated ethane in the presence of a catalyst containing ruthenium as an essential component.
The chlorinated fluorinated ethane to which the method of the present invention is applied is an ethane having at least one chlorine atom and at least one fluorine atom, and particularly, the following formula (1) CF ₃ -CClX ₁ X ₂ (1) [In (1), X ₁ and X ₂ are hydrogen, fluorine or chlorine. ] The chlorinated fluorinated ethane represented by the following is preferable, and specifically, 1,1,1-trichloro-2,2,2
-Trifluoroethane (hereinafter referred to as CFC-113a), 1,1-dichloro-2,2,2-trifluoroethane (hereinafter referred to as CFC-123), 1-chloro-
2,2,2-trifluoroethane (hereinafter CFC-133
It is called a. ), 2,2-Dichloro-1,1,1,2-tetrafluoroethane, 2-chloro-1,1,1,2-
Such as tetrafluoroethane, especially CFC-113
a is preferred. Further, these chlorinated fluorinated ethanes may be mixed and used. When mixed and used, it is possible to form not only a dimer composed of a single reactive species but also a dimer composed of mutually reactive species.

The ruthenium catalyst of the present invention can be used in various forms of a simple substance of metal, for example, powder, metal black, wire net, sol, etc., but it is usually used as a supported catalyst, and its carrier is activated carbon, alumina, fluorinated. Aluminum, partially fluorinated alumina, zirconia, partially fluorinated zirconia, calcium fluoride, silica alumina, partially fluorinated silica alumina, silica,
Various carriers can be used, such as partially fluorinated silica, but activated carbon is especially recommended. It is recommended that the supported amount of ruthenium with respect to the weight of the carrier be 0.01 to 20% by weight, preferably 0.5 to 10% by weight.
If it is 0.01% by weight or less, the volume of the catalyst layer must be increased, and if it is 20% by weight or more, it is difficult to support ruthenium in a uniformly dispersed state and control the reaction, which is not preferable.

The method of supporting ruthenium on the carrier in the catalyst of the present invention can be produced by a conventionally known method. For example, it can be produced by immersing the carrier in a solution containing a ruthenium compound, and air-drying and heat-drying. In this case, finally 200 ~
Baking is performed at 500 ° C., preferably 250 to 400 ° C. Further, before starting the reaction, it is necessary to reduce the supported metal in advance in a hydrogen atmosphere or in the presence of a reducing agent such as hydrazine at 300 to 500 ° C. Fifty
When the temperature is higher than 0 ° C, the activity of the catalyst is lowered, which is not preferable.

The metal to be supported is not particularly limited as long as it is a compound capable of forming a solution, but ruthenium chloride, sodium hexachlororuthenate, potassium hexachlororuthenate and the like are preferable.

The solvent used for preparing the catalyst may be water or an aqueous solution of ammonia, hydrochloric acid, nitric acid, sulfuric acid, or the like, or an organic solvent such as methanol, ethanol, acetone, methylene chloride, chloroform, benzene, or the like. Further, water, an aqueous solution or a mixture of organic solvents can be used.

Further, other elements can be appropriately added in order to further improve the catalyst life and the selectivity. For example, 1a group, 2a group, 3b group, 4b group, 5b group, 6b can be added.
Group, 7b group, 8 group, 1b group, 2b group, 3a group, 4a group,
One or more elements of the 5a group and the 6a group (however,
It is also possible to add (excluding ruthenium). As a method for adding these elements, it is convenient to simultaneously add the target element in the form of a compound to the solution in the method for supporting ruthenium described above, but separately to a solution containing only these or salts of these elements. It is also possible to adopt a method of dipping and subjecting to the same post-treatment.

In the present invention, hydrogen gas is preferably allowed to coexist during the reaction. Hydrogen gas has a function of preventing deterioration of the catalyst. The amount of hydrogen used is in the range of 0.5 to 20 mol, preferably 3 to 7 mol, based on chlorinated fluorinated ethane. If desired, an inert gas such as nitrogen, argon or helium may be allowed to coexist during the reaction to dilute the reaction substrate.

The reaction temperature should be determined in consideration of the raw material, conversion rate, selectivity and catalyst life, but it is from 100 to 5
A range of 00 ° C, more preferably 150-400 ° C is recommended. When the temperature is lower than 100 ° C, the conversion rate is low,
If the temperature exceeds 0 ° C, the selectivity decreases.

When the method of the present invention is carried out in the gas phase, the reaction pressure is not particularly limited, but is 1 to 100 kg /
Perform in cm ² . If it is less than 1 kg / cm ² , the shape of the reactor becomes large, which is not preferable, and if it is 100 kg / cm ² or more, it is not particularly preferable from the viewpoint of the strength of the apparatus. When the reaction is performed in the gas phase, the contact time is 0.5 to 200.
A range of seconds is applicable, but a range of 2 to 60 seconds is preferable.

The chlorinated fluorinated C ₄ hydrocarbon produced by the method of the present invention may have a single bond, a double bond or a triple bond at the 2-position. For example, the chlorinated fluorinated ethane of the formula (1) is used. When used as a raw material, CF ₃ —CY ₁ Y ₂ —CY ₃ Y ₄ —CF ₃ (2) [In the formula, Y ₁ , Y ₂ , Y ₃ and Y ₄ are hydrogen, fluorine or chlorine. Fluorinated butane represented _{by], CF 3 -CY 1 = CY} 3 -CF 3 (3) [ wherein, Y ₁ and Y ₃ is hydrogen, fluorine or chlorine. ] Fluorine-containing butene-2 and perfluorobutyne-2 shown by these are obtained. In the method of the present invention,
A product in which some chlorine is replaced by hydrogen can also be obtained.

Chlorinated fluorides synthesized by the method of the present invention
Elementary C_FourHydrocarbons are unreacted hydrogen, hydrogen chloride by-product organic
Reaction with unreacted raw materials
Spilled or recovered from the reactor, but from these mixtures
Chlorinated Fluorinated C _FourTo get hydrocarbons usually
All you have to do is follow the method used. For example, from the reactor
Passing the spilled or recovered mixture through a water scrubber
To remove acidic components such as hydrogen chloride, then unreacted
Hydrogen gas can be obtained by cryogenic separation or compression separation.
The method of distilling and separating the organic components obtained is
As an example.

When the method of the present invention is carried out in the liquid phase, it is in the presence or absence of a solvent inert to the hydrogenation reaction, such as water, diethyl ether, tetrahydrofuran, methanol, ethanol, isopropanol and the like. To do. In this case, the reaction pressure is not particularly limited, but is 1 to 100 kg / cm ² . 1 kg / cm ²
If less than 1, the shape of the reactor becomes large, which is not preferable.
When the pressure is 00 kg / cm ² or more, the strength of the device is not particularly preferable. The reaction temperature is related to the reaction rate and the catalyst life, but is 20 to 200 ° C., more preferably 30 to 200 ° C.
A range of 150 ° C is recommended. If the temperature is 20 ° C or lower, the reaction takes time, and if it is 200 ° C or higher, perhydrogenation occurs, which is not preferable. The reaction time is about 30 minutes to 10 hours, but is not particularly limited. The reaction system may be either a batch system or a flow system, but the reaction conditions are naturally slightly different. Further, when the method of the present invention is carried out in the liquid phase, an acid acceptor can be coexistent. The acid acceptor is not particularly limited as long as it reacts with hydrogen chloride to form a stable salt or complex or adsorbs it, and examples thereof include alkali metal, alkaline earth metal oxides, hydroxides and carbonic acid. salt,
There are solid adsorbents such as amines and alumina such as hydrogen carbonate, and specifically, sodium hydroxide, potassium hydroxide, sodium carbonate, sodium hydrogen carbonate, calcium hydroxide, barium hydroxide, trimethylamine, triethylamine, etc. Pyridine and the like can be mentioned, and other examples include aluminum hydroxide and the like.

[0019]

EXAMPLES The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

Preparation Example 1 0.20 g of ruthenium chloride monohydrate was dissolved in 50 ml of pure water, and 50 ml of activated carbon (3I manufactured by JGC Chemical Co., Ltd.) was added to this solution.
Was soaked for 20 hours, and then water was evaporated to dryness using an evaporator. Air dry this catalyst at 300 ℃
The catalyst was prepared by calcining at 2.5 hours.

Example 1 Inner diameter 2.5 cm, length 40 c equipped with external tubular electric furnace
m of the reaction tube made of stainless steel with the catalyst 50 prepared in Preparation Example 1
ml was charged and the temperature rise was started while flowing hydrogen. 40
The catalyst was hydrogen-reduced at 0 ° C. at a hydrogen flow rate of 100 ml / min for 2 hours, and then cooled to a reaction temperature of 200 ° C.
FC-113a and hydrogen 35ml / min, 140 respectively
It was introduced into the reaction tube at a flow rate of ml / min. The contact time was 17 seconds. The results of gas chromatograph analysis of the gas flowing out of the reaction tube at 2 hours after the start of the reaction are shown in Table 1.

The conversion rate was 9 even after 10 hours.
The dimer selectivity was high, which was 9.45%.

[0023]

[Table 1]

In the table,% of the composition of the reaction product is% by weight.
HFC-143a means 1,1,1-trifluoroethane. Comparative Example 1 A reaction test was conducted under the same operations and conditions as in Example 1 except that 5% Ni / C was used as the catalyst and the reaction temperature was 300 ° C.

The 5% Ni / C catalyst was prepared by the same operation and conditions as in Preparation Example 1, except that 4.96 g of nickel nitrate hexahydrate was used as the nickel metal salt. The results are shown in Table 1. As a result of examining the catalyst life,
The reaction rate of CFC-113a was 30.55 after 10 hours.
%, And catalyst deterioration was recognized.

[0026]

As is apparent from the results of the examples, the method of the present invention is characterized by a high reaction rate, a high selectivity and a long life when producing a dimer of chlorinated fluorinated ethane. Since it has, an industrially advantageous manufacturing method can be provided.

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Claims (3)

[Claims] 1. A method for dimerizing chlorinated fluorinated ethane in the presence of hydrogen and a catalyst, which comprises using a catalyst containing ruthenium as an essential component. 2. The method for dimerizing chlorinated fluorinated ethane according to claim 1, wherein the chlorinated fluorinated ethane is a chlorinated fluorinated ethane represented by the following formula (1). CF In _{3 -CClX 1 X 2 (1)} [(1), X 1, X 2 is hydrogen, fluorine or chlorine. ] 3. The method for dimerizing chlorinated fluorinated ethane according to claim 1, wherein the chlorinated fluorinated ethane is 1,1,1-trichloro-2,2,2-trifluoroethane.