JPH08198783A - Production of 1,1,1,3,3-pentafluorobutane - Google Patents

Abstract

PURPOSE: To provide an industrially advantageous method for producing 1,1,1,3,3- pentafluorobutane by which by-products are utilized. CONSTITUTION: This method for producing 1,1,1,3,3-pentafluorobutane comprises the following four steps: (1) a step for reacting 1,1,1-trichloroethane or vinylidene chloride with hydrogen fluoride in the liquid phase in the absence of a catalyst, (2) a step for removing substances having a lower boiling point than that of 1,1,1-trichloroethane from the resultant reactional product, (3) a step for fluorinating a mixture comprising substances having a higher boiling point than that of the 1,1,1-trichloroethane in the liquid phase with hydrogen fluoride using pentavalent antimony as a catalyst and (4) a step for distilling the fluorination product obtained in the step (3).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applicable to foaming agents for resins such as urethane foam, cleaning solvents, and refrigerants.
The present invention relates to an industrially advantageous method for producing 1,1,3,3-pentafluorobutane.

[0002]

BACKGROUND OF THE INVENTION 1,1,1,3,3-Pentafluorobutane is obtained by fluorinating 1,1,1-trichloro-3,3-difluorobutane with hydrogen fluoride in an autoclave in the presence of mercury oxide. (McBee, Hausc
h, Ind. Eng. Chem. 39 [1947] 42
0), similarly, it is known that it can be obtained by fluorinating 3,3-dichloro-1,1,1-trifluorobutane (Henne, Hinkamp, J. Am. Che.
m. Soc. 67 [1945] 1195, 1198).

Further, 1,1,1,3-tetrachloro-1
It is known that it can be obtained by fluorinating butene with hydrogen fluoride in the presence or absence of an antimony pentachloride catalyst (Japanese Patent Laid-Open No. 5-171185).

On the other hand, when 1,1,1-trichloroethane is fluorinated with hydrogen fluoride to synthesize 1,1-dichloro-1-fluoroethane and 1-chloro-1,1-difluoroethane, 1,1,1 A small amount of 3,3,3-pentafluorobutane is produced as a by-product.
No. 5937.

[0005]

SUMMARY OF THE INVENTION 1,1,1-trichloro-3,3-difluorobutane, 3,3-dichloro-1,1,1-trifluorobutane, 1, which are raw materials for the above-mentioned production method, All of 1,1,3-tetrachloro-1-butene and the like are substances that are difficult to obtain in large quantities, and the method in which these must be used is not industrially applicable.

Further, the method of separating the by-product of the fluorination reaction of 1,1,1-trichloroethane from the mixture with the main product described in JP-A-2-295937 is also described in the specification. As stated, 1, 1, 1, 3, 3
-Pentafluorobutane is azeotropic with the main product, 1,1-dichloro-1-fluoroethane, so that there is a problem in that purification is troublesome.

Therefore, the present invention provides a method for producing 1,1,1,3,3-pentafluorobutane, which could not be industrially produced by conventional methods, by appropriately combining the established chemical operations. is there.

[0008]

[Means for Solving the Problems] The inventors of the present invention have used industrially relatively readily available substances as starting materials.
When a method for producing 1,1,3,3-pentafluorobutane was examined, 1,1,1-trichloroethane or vinylidene chloride was fluorinated with hydrogen fluoride to give 1,1-
When the high-boiling substance by-produced during the production of dichloro-1-fluoroethane is fluorinated with hydrogen fluoride, 1,1,1,
It was found that 3,3-pentafluorobutane was produced. Gas chromatograph shows that fluorination of a reaction liquid containing a high boiling point component retained in a reactor in the production of 1,1,1-trichloroethane produces 1,1,1,3,3-pentafluorobutane on the basis of the above findings. Analysis revealed that 1,1-dichloro-1-fluoroethane was simultaneously produced in a large amount, so that 1,1,1,3,3-pentafluorobutane of high purity could not be obtained by distillation. Therefore, the present inventors have previously
In the production of 1-trichloroethane, the reaction liquid retained in the reactor is subjected to distillation to remove a substance that can be converted to 1,1-dichloro-1-fluoroethane,
The inventors have found that 3,3-pentafluorobutane can be easily separated and the yield of the whole process can be remarkably improved, and the present invention has been completed.

That is, the present invention is a method for producing 1,1,1,3,3-pentafluorobutane including the following four steps. A step of reacting 1,1,1-trichloroethane or vinylidene chloride and hydrogen fluoride in a liquid phase without a catalyst.

A step of removing a substance having a boiling point of 1,1,1-trichloroethane or lower from the reaction product. A step of fluorinating the mixture of the substance having a boiling point higher than that of 1,1,1-trichloroethane obtained in 1. in a liquid phase with hydrogen fluoride using pentavalent antimony as a catalyst.

Distilling the fluorinated product obtained in. The step of the present invention is a known step of synthesizing 1,1-dichloro-1-fluoroethane by reacting 1,1,1-trichloroethane or vinylidene chloride with hydrogen fluoride in a liquid phase without a catalyst. . The reaction type is not particularly limited, but for example, in a stainless steel reactor, 1,
A production method can be shown in which 1,1-trichloroethane and hydrogen fluoride are fed and stirred, and the closed system or the product is allowed to flow out of the reaction system in a gaseous or liquid state. The reaction conditions include a reaction temperature of 40 to 100 ° C.,
The reaction pressure is ² to 50 kg / cm ² , and hydrogen fluoride /
It is necessary to set the molar ratio of 1,1,1-trichloroethane to 1 or more. The molar ratio of hydrogen fluoride and 1,1,1-trichloroethane is preferably a particularly sufficient excess when reacting in a flow system, and even if it is 10 or more, there is no problem and hydrogen fluoride is extremely 1 Hydrogen fluoride may be in excess so that 1,1,1-trichloroethane is dissolved.

In the step of the present invention, the boiling point (74 ° C.) of 1,1,1-trichloroethane is obtained from the reaction liquid containing the by-product mainly containing the substance having 4 carbon atoms produced in the step of
This is a step of removing the following components. This step may be performed by any operation and is usually performed by distillation, but 1,1,1-trichloroethane is sufficiently fluorinated beforehand, and 1,1-dichloro-1-fluoroethane or 1
It is also preferable to change to a low boiling point substance such as -chloro-1,1-difluoroethane and then carry out the distillation.

The by-products produced in the step (1) are mainly chlorinated fluorinated butanes and chlorinated fluorinated butenes, and contain a small amount of chlorinated fluorinated hexanes. In the present invention, it is important to remove compounds having a boiling point not higher than that of 1,1,1-trichloroethane among them. When the halogenated butanes in which 1,1,1-trichloroethane remains is subjected to the fluorination reaction in the next step, the 1,1,1-trichloroethane is fluorinated more easily than the halogenated butanes. , 3, 3
-1,1-dichloro-azeotroping with pentafluorobutane-
The target 1,1, for producing 1-fluoroethane
It is difficult to purify 1,3,3-pentafluorobutane and must be avoided. As a result, the material obtained in this the process is higher boiling point than _{1,1,1-trichloroethane, CCl 3-p F p -CH} 2 -CCl 2-q F q CH 3 CCl 2-r F r = CH _{-CCl 2-s F s -CH 3} ( wherein, p is 0, 1, 2 or 3, q, r, s are each independently 0, 1 or 2, and, p + q <
4, r + s <4. ) 1,1,1,3,3-pentahalogenobutane having a fluorine number of 3 or less or 1,
A halogenated butane or halogenated butene mainly containing 1,3,3-tetrahalogeno-1-butene.

In this step, not only components having a boiling point of 1,1,1-trichloroethane or less but also components having a higher boiling point than 1,1,1,3-tetrachloro-1-butene are removed. This is preferable in terms of simplification of the reaction process and downsizing of the reaction apparatus. 90 for that
A component having a boiling point of 95 ° C. or higher in mmHg may be removed by distillation.

In the process of the present invention, 1, 1, 1, 3,
3-Pentahalogenobutane or 1,1,3,3-tetrahalogeno-1-butene is fluorinated with hydrogen fluoride using pentavalent antimony as a catalyst. This reaction is based on the fluorination of many chlorinated hydrocarbons. It suffices to carry out according to the reaction format and reaction conditions that are being carried out. To give a specific example, a catalyst made by charging an antimony compound that can become pentavalent in the activated state as a catalyst into a stainless steel reactor and introducing chlorine and / or hydrogen fluoride in advance to heat the catalyst By feeding hydrogen fluoride and a mixture mainly composed of halogenated butanes or halogenated butenes obtained in the step (1) to the closed system or flowing the product in a gaseous or liquid state out of the reaction system. Can be shown. The reaction conditions include a reaction temperature of 40 to 100 ° C.,
Reaction pressure ^{2 to} 50 kg / cm ² , hydrogen fluoride / 1,1,
It is necessary that the molar ratio of 1-trichloroethane be 2 or more. When the hydrogen fluoride and the mixture are reacted in a flow system, it is preferable that the molar ratio is 3 to 50, particularly preferably a sufficient excess. Below 3 the reaction rate is low and 5
When it is 0 or more, hydrogen fluoride flows out of the reaction system in an unreacted state, which is not preferable because a device and operation for recovery and reuse are required. It is well known to those skilled in the art that the amount of catalyst varies depending on whether the reaction type is a flow type or a batch type, but in the case of the latter case, 1 part by weight of antimony is expressed in terms of antimony pentachloride. The reaction raw material is 0.1 to 100 parts by weight, preferably 0.5 to 30 parts by weight. A solvent inert in the reaction system for preventing deactivation of the catalyst, for example, 1,2-dichloroethane,
Chlorinated hydrocarbons such as 1,1,2-trichloroethane and 1,1,2,2-tetrachloroethane, 1,1,2-trichlorotrifluoroethane, 1,2,2-trichloro-1,1-difluoroethane, etc. Fluorinated chlorinated hydrocarbons and the like can be used.

Since the product 1,1,1,3,3-pentafluorobutane has a boiling point of 40 ° C. and is higher than that of the raw material hydrogen fluoride, it is not reacted when it is taken out from the reaction system in a gas state. It is often accompanied by hydrogen fluoride, but this may be washed with water or a basic solution or liquefied to form two phases and separated, and then the same washing may be performed.

The product of the method of the present invention is 1,1,
Since the process does not involve a compound that is azeotropic with 1,3,3-pentafluorobutane, a sufficient rectification effect can be obtained by ordinary distillation. Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to these embodiments.

[0018]

【Example】

[Example 1] 2123 g of 1,1,1-trichloroethane and 1575 g of hydrogen fluoride were charged into a 10-liter stainless reactor equipped with a reflux condenser and a stirrer, and the temperature of the reactor was set to 65 ° C and the temperature of the reflux condenser was adjusted. 60 ° C., reaction pressure 6
While maintaining at kg / cm ² , 1,1,1-trichloroethane was fed at a feeding rate of 2100 g / hr and hydrogen fluoride of 1660 g / hr. Hydrogen chloride, the main product 1,1-dichloro-1-fluoroethane, was allowed to flow out through the reflux device,
After washing with water, organic substances were collected in a trap cooled to -78 ° C. After continuing the reaction for 50 hours, the reaction liquid retained in the reactor was washed with water to recover 7200 g of an organic substance, which was analyzed by gas chromatography to find that 1,1-dichloro-1-fluoroethane 54.0 % C4H5ClF4 1.2% C4H4ClF3 0.1% 1,1,1-trichloroethane 31.0% C4H5Cl2F3 2.2% 1,1,2-trichloroethane 4.8% C4H5Cl3F2 3.1% C4H4Cl3F 1.0% C4H5Cl4F 0 The composition was 0.9% C4H4Cl4 0.2% and other 1.5%.

The recovered organic matter is distilled in a distillation column having 20 theoretical plates to remove 1,1,1-trichloroethane and components having a lower boiling point than that, and C4H5Cl2F3 9.3% 1,1,2- 820 g of a mixture having the composition of trichloroethane 37.9% C4H5Cl3F2 24.4% C4H4Cl3F 7.9% C4H5Cl4F 1.6% C4H4Cl4 6.1% and other 11.8% were obtained.

A 2 liter stainless steel reactor equipped with a reflux condenser and a stirrer was charged with 300 g of antimony pentachloride dissolved in 480 g of 1,1,2,2-tetrachloroethane, and 600 g of hydrogen fluoride was added thereto with stirring. The temperature of the reactor was raised to 30 ° C. by press-fitting, the temperature was maintained for 10 minutes, and the valve on the upper part of the reflux tower was adjusted so that the pressure became 6 kg / cm ² . Then, the temperature of the reactor was raised to 40 ° C. while press-fitting the mixture obtained above at a rate of 50 g / min, and the pressure was adjusted to 6
The valve on the upper part of the reflux tower was adjusted so as to be kg / cm ² .
After the injection of 700 g of the mixture was completed and 1 hour after the reaction temperature reached 40 ° C., the valve in the upper part of the reflux tower was gradually opened to remove the gas from the reactor and the acid trap containing water and sulfuric acid were added. After passing through the dehydration trap, an attempt was made to recover organic substances using a deep-cooled trap. After the pressure of the reactor was lowered and the outflow of the contents was delayed, nitrogen gas was blown into the contents of the reactor to continue the organic matter recovery. Organic substances settled in the acid trap and were hardly collected in other traps. The recovered organic matter was 180 g, and its composition was analyzed to find that 1,1,1,3,3-pentafluorobutane was 87.1.
%, C4H5ClF4 was 10.1%, and 1,1-dichloro-1-fluoroethane was not contained.

In this reaction, 1,1,2-trichloroethane did not react and no by-product derived from it was detected. When the collected organic substance was distilled, 130 g of 1,1,1,3,3-pentafluorobutane having a purity of 99.6% without any azeotropic component was obtained.

[Comparative Example 1] 1, 1, obtained in Example 1
An attempt was made to separate a mixed solution of 50 g of 1,3,3-pentafluorobutane and 50 g of 1,1-dichloro-1-fluoroethane using a distillation column packed with a glass helix packing having 20 theoretical plates. However, these components exhibited azeotrope-like behavior, and a distillate having a composition of 23% by weight of 1,1,1,3,3-pentafluorobutane was obtained.

[0023]

The manufacturing method of the present invention is 1, 1, 1, 3,
Since it does not contain a component that is azeotropic with 3-pentafluorobutane, it is characterized by good distillation efficiency, and is therefore an industrially superior method.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display area C07C 17/278 // C07B 61/00 300

Claims (1)

[Claims] 1. A 1,1,1,3,3-including the following four steps:
Method for producing pentafluorobutane. A step of reacting 1,1,1-trichloroethane or vinylidene chloride and hydrogen fluoride in a liquid phase without a catalyst. A step of removing a substance having a boiling point of 1,1,1-trichloroethane or lower from the reaction product. A step of fluorinating the mixture of the substance having a boiling point higher than that of 1,1,1-trichloroethane obtained in 1. in a liquid phase with hydrogen fluoride using pentavalent antimony as a catalyst. A step of distilling the fluorinated product obtained in.