WO1993009081A1

WO1993009081A1 - Process for producing 1,1,1,2,2,4,4,4-octafluorobutane

Info

Publication number: WO1993009081A1
Application number: PCT/JP1992/001399
Authority: WO
Inventors: Hirokazu Aoyama; Souichi Ueda
Original assignee: Daikin Industries, Ltd.
Priority date: 1991-11-01
Filing date: 1992-10-29
Publication date: 1993-05-13
Also published as: JPH05124987A

Abstract

A process for producing 1,1,1,2,2,4,4,4-octafluorobutane in a high yield by reducing 3,3-dichloro- or 3,3-dibromo-1,1,1,2,2,4,4,4-octafluorobutane.

Description

Specification

Process for producing 1,1,1,2,2,4,4,4-octafluorobutane

The present invention relates to a method for producing 1,1,1,2,2,4,4,4-octafluorobutane (HFC-338mfc). HFC-338mic is expected to be used for foaming agents, refrigerants, cleaning agents, etc., just like conventional fluorocarbons, and has the advantage of not destroying stratospheric ozone at all because it does not contain chlorine. I have.

Conventional technology

Conventionally, as a method for obtaining HF C 338mfc, as described in Journal of Chemical Society (J. Chem. Soc.) 1955, p. 3005, 1, 1, 1, 2, 2, It is known to fluorinate 4,4-heptafluoro-1-butodobutane using silver fluoride (Hg ₂ F ₂ ) to obtain a 48% yield. However, in this case, the yield is low, and Hg ₂ F ₂ is used, which is not an industrial and economical synthesis method.

Summary of the Invention

The present invention seeks to provide a method for industrially and economically producing HF C 338mic in high yield.

That is, the inventor of the present invention has proposed a 3,3-dichloro-mouth or dibromo-monomer obtained by adding 1,1-dichlorotetrafluoroethane or 1,1-dibromotetrafluoroethane to tetrafluoroethylene. 1, 1, 1, 2, 2,

4, 4, 4 specializing in reducing one-year-old kutafluorobutane 1, 1, 1,

2, 2, 4, 4, 4 Provide a method for producing one-year-old kutafluorobutane.

Detailed description of the invention

The method of reduction in the present invention is a method of performing under light irradiation, using zinc. , A method using hydrogen in the presence of a catalyst, a method using potassium acetate and an alcohol, and the like.

When the reduction is performed under light irradiation, alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol and sec-butanol are preferably used as a proton source. More preferably, general alcohols such as isopropanol and sec-butanol are used. The reaction proceeds smoothly by adding an alcohol into the reaction system to capture HCl or HBr generated as the reaction proceeds.

As the type of alkaline liquor, those having weak basicity such as carbonated lime, sodium carbonate, calcium carbonate, potassium bicarbonate and sodium bicarbonate are preferred. Further, without using such an acid scavenger, H C1 or H Br generated by heating may be driven out of the system.

The light source is not particularly limited as long as it generates light having a wavelength of 40 O nm or less. For example, a high-pressure mercury lamp and a low-pressure mercury lamp are preferable. The reaction temperature in the reduction under light irradiation is usually in the range of 0 to 100 ° C, preferably in the range of 10 to 80 ° C, and the reaction pressure is not particularly limited, but is from atmospheric pressure to 2 KgZcm ² G It is preferable to carry out within the range.

As a solvent used when reducing with zinc, a solvent that is a proton source for the reduction reaction is preferable, and alcohols such as methanol, ethanol, isopropanol, ethylene glycol, and propylene glycol are preferably used. Powder or granular zinc is preferred as zinc, and zinc powder is most preferred. The amount of zinc used should be at least equimolar to the chlorine or bromine to be reduced, that is, at least 2 molar equivalents to the starting material. The reaction is usually carried out in a temperature range from room temperature to 120 ° C, preferably 40 to 100 ° C. The reaction pressure is not particularly limited, either, from atmospheric pressure to 8 KgZcm ² It is preferably carried out in a pressure range of G.

When the reduction is performed using hydrogen in the presence of a catalyst, the reduction can be performed in either a gas phase or a liquid phase reaction system. As the reduction catalyst, any of a noble metal catalyst such as platinum, palladium, rhodium and ruthenium, and a hydrogenation catalyst such as Raney nickel can be used, but a noble metal catalyst is particularly preferable. As the carrier of the reduction catalyst, for example, alumina, activated carbon, and the like are suitably used. As a supporting method, a conventional method for preparing a noble metal catalyst can be applied. It is preferable to reduce the catalyst before use in order to obtain stable catalytic activity, but it is not always necessary.

The ratio of hydrogen to starting material can vary widely. Normally, stoichiometric amounts of hydrogen are used to hydrogenate chlorine or bromine atoms, but in order to increase the conversion of the starting material and the selectivity of the target compound, a considerably large amount, based on the number of moles of the starting material, For example, 4 times or more hydrogen may be used. The reaction temperature is suitably from 80 to 350 ° C., particularly preferably from 100 to 200 ° C. in a gas phase reaction. The contact time is from 0, 1 to 200 seconds, particularly preferably from 1 to 60 seconds. .

When the reduction reaction is performed in the liquid phase, it is possible to use a solvent without solvent, but alcohols such as methanol, ethanol, and isopropanol; ethers such as tetrahydrofuran, dioxane, and ethylene glycol dimethyl ether; and solvents such as acetic acid and pyridine. The reaction may be performed in the reaction. In addition, since HC 1 or HBr generated as the reduction progresses often reduces the activity of the catalyst, the reaction system may contain an alkaline solvent, such as sodium hydroxide, potassium hydroxide, or calcium hydroxide. The generated acid may be captured by adding water, soda glyme, ammonia water, or the like. The reaction temperature in the liquid phase reaction is preferably room temperature to 150 ° C., and the reaction pressure is preferably atmospheric pressure to 50 cm ² G. As a solvent used in the reduction with acetic acid and alcohol, a solvent that is a proton source for the reduction reaction is preferable, and alcohols such as methanol, ethanol, isopropanol, ethylene glycol and propylene glycol are preferable, and isopropanol is preferable. Is particularly preferred. The amount of potassium persulfate should be at least one equivalent to the chlorine or bromine atom to be reduced, that is, at least 2 molar equivalents to the starting material. The reaction is usually carried out at a temperature in the range of room temperature to 120, preferably 40 to 100 ° C. Although the reaction pressure is not particularly limited, it is preferable to carry out the reaction in a pressure range from atmospheric pressure to 8 kgZcm ² G.

The invention's effect

As described above, the present invention reduces 1,3,3-dichro- or jib-mouth 1,1,1,2,2,4,4,4 one-year-old kutafluorobutane to provide a high yield of 1 , 1,1,2,2,4,4,4 can produce otatafnoroleolobutane.

Example

Example 1 (photoreduction)

3,3-Dichloro-1,1,1; 1,2,2,4,4,4-octafluorobutane 27.lg, sodium carbonate 2 1 in a 500 ml quartz photoreaction vessel equipped with a condenser .2 g and isopropanol 30 Oinl were charged. After purging with nitrogen, the system was irradiated with a high-pressure mercury lamp while stirring. The reaction temperature was kept at 25 to 30 ° C and the reaction was continued for about 4 hours. When the reaction mixture was analyzed by gas chromatography, the conversion of the raw material was 100% and 1,1,1,2,2,4,4,4-octafluorobutane was formed with a selectivity of 95%. Was.

Example 2 (zinc)

A 30 Oml glass reactor equipped with a condenser and a dropping funnel was charged with zinc powder (14.5 g) and ethanol (10Οπιΐ). Heat to reflux while stirring, and add the dripping funnel 2,2--jib-mouth 1,1,1,3,3,4,4,4 Lobutane 2 Og was charged over 1 hour, and the reaction was further heated to reflux for 1 hour and continued. After the reaction mixture was cooled and analyzed by gas chromatography, the conversion of the raw material was 100%, and 1,1,1,2,2,4,4,4-octafluorobutane was selected. It was produced at 85%.

Example 3 (zinc)

In Example 2, 3,3-dichloro-1,1,1,2,2,4,4 instead of 3,3-dibromo-1,1,1,2,2,4,4,4-octafluorobutane The reaction was carried out in the same manner except that 15 g of 4-octafluorobutane was used. The conversion of the raw material was 100%, and 1,1,1,2,2,4,4,4-octafuronole Lobutane was formed with a selectivity of 80%.

Example 4 (Hydrogen gas phase reaction)

A reaction tube made of Hastelloy C with an inner diameter of 20 was filled with 40 ml of activated carbon-supported palladium catalyst (supporting rate: 0.5% by weight). After flowing hydrogen at 120 ° C at a flow rate of 8 OccZmin. For 2 hours, gasified at a reaction temperature of 120 ° C was 3,3-dichloro-1,1,1,2,2,4,4,4. —Octafluorobutane was passed through the reaction tube at a flow rate of 4 Occ min. And hydrogen at a flow rate of 10 OccZmin. After removing the acid content from the reactor outlet gas, it was collected in a cold trap at 178 ° C and analyzed by gas chromatography. The conversion of the raw material was 95%, and the target 1, 1, 1, 2 , 2,4,4,4 One-year-old kutafluorobutane was produced with a selectivity of 85%.

Example 5 (hydrogen liquid phase reaction)

In a SUS 316 autoclave with an internal volume of 300 ml, ethylene glycol dimethyl ether 150 ml, hydroxylation capacity 16.8 g and 3,3-jib mouth 1,1,1,2,2,4,4,4-octaful 36 g of orobutane was charged.

After reducing the pressure inside the system, pressurize hydrogen to 20 kg / cm ² G and stir Heated to 100 ° C, the hydrogen consumed by the reaction was added continuously and the reaction continued until no more hydrogen was consumed. After cooling, the reaction mixture was analyzed by gas chromatography. The conversion of the raw materials was 10 o ° c, and the desired 1,1,1,2,2,4,4,4-octafluo was obtained. Lobutane was formed with a selectivity of 80%.

Example 6 (potassium acetate)

In a 30 Oml glass reaction vessel equipped with a condenser and a dropping funnel, 21.8 g of potassium diacid and 100 ml of isopropanol were charged. The mixture was heated to reflux with stirring, and the dropping funnel 3,3-jib and mouth 1,1,1,2,2,4,4,4-octafluorobutane 20 g were charged over 1 hour. The reaction was continued while heating at reflux for 1 hour. After the reaction mixture was cooled and analyzed by gas chromatography, the conversion of the raw material was 100%, and the 1,1,: U2,2,4,4,4-octafluorobutane was selected at a conversion rate of 86%. % Was generated.

Example 7 (potassium acetate)

In Example 6, instead of 3,3-dibromo-1,1,1,2,2,4,4,4-octafluorobutane, 3,3-dichloro-1,1,1,2,2,4 The reaction was carried out in the same manner except that 15 g of 1,4-octafluorobutane was used. The reaction mixture was cooled and analyzed by gas chromatography. The conversion of the raw materials was 100%. , 1, 2, 2, 4, 4, and 4-octafluorobutane were produced with a selectivity of 94%. -

Claims

The scope of the claims

1. 3,3-Dichro or jib mouth 1,1,1,2,2,4,4,4-reducing 1,1,1,2,2,4 characterized by reducing octafluorobutane , 4, 4 One-year production method of kutafluorobutane.