JPH04230336A - Production of dichloropentafluoropropane - Google Patents

Abstract

PURPOSE:To enable high-yield production of dichloropentafluoropropane (R225) which has been hardly available in high purity and to improve the selectivity of R225cb in R225. CONSTITUTION:The objective dichloropentafluoropropane can be produced by adding dichlorofluoromethane to 1,1-dichlorodifluoroethylene and fluorinating the obtained tetrachlorotrifluoropropane.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing dichloropentafluoropropane (R225). Hydrogen-containing chlorofluoropropanes are expected to be used as blowing agents, refrigerants, cleaning agents, etc., similar to conventionally used fluorocarbons.

0002

BACKGROUND OF THE INVENTION As a method for producing R225, it has been known to synthesize R225 by adding dichlorofluoromethane (R21) to tetrafluoroethylene in the presence of aluminum chloride.

0003

[Problems to be Solved by the Invention] However, this method produces reaction by-products that have close boiling points to the target product and are difficult to separate by normal methods such as distillation, so it is difficult to obtain a highly pure product. It has the disadvantage of requiring multiple purification steps.

0004

[Means for Solving the Problems] As a result of intensive research into an efficient method for producing R225, the present inventors have discovered that 1,1-
After adding R21 to dichlorodifluoroethylene to produce tetrachlorotrifluoropropane (R223), this is fluorinated to produce R in high yield.
The inventors have discovered that 225 can be obtained and have come to provide the present invention.

[0005] The details of the present invention will be explained below along with examples. That is, when R21 is subjected to an addition reaction with 1,1-dichlorodifluoroethylene in the presence of a catalyst, R223 is obtained in high yield as shown in the following formula. CCl2 = CF2 + CHCl2 F acid catalyst → CCl2 FCF2 CHCl2 (R223ca)
+CCl3 CF2 CHClF (R223cb) +C
ClF2 CCl2 CHClF(R223ab)+C
F3 CCl2 CHCl2 (R223aa)

00
06 The acid catalyst used in this reaction is B, Al, Ga.
, In, Fe, Ni, Co, Sb, Nb, Sn, Ti,
A halide or halide oxide containing at least one element selected from the group consisting of Zr, Hf, W and Ta is preferred.

[0007] As the halide catalyst, BF3, A
lCl3, GaCl3, InCl3, FeCl3
, NiCl2 , CoCl2 , SbF5 , NbCl
5, SnCl2, TiCl4, ZrCl4, H
fCl4, WCl6, TaCl5, etc. are preferred.

[0008] As the halogenated oxide catalyst, an oxide consisting of one type of metal element or a composite oxide consisting of two or more metal elements is combined with a suitable halogenating agent such as trichlorofluoromethane (R11), dichlorodifluoromethane (R12).
), chlorofluorocarbons such as trichlorotrifluoroethane (R113), hydrochlorofluorocarbons such as R21, chlorodifluoromethane (R22), or those prepared by treatment with chlorine, hydrogen fluoride, fluorine gas, etc. preferable.

When making a composite oxide, metal elements other than those mentioned above, such as Si, Zn, Mg, Cr, Cu, V, Sn,
Of course, it is also possible to further add at least one kind of Bi, Mo, etc.

[0010] The conditions for preparing the catalyst vary depending on the oxide and halogenating agent used, but the halogenating agent is usually used in an excess amount relative to the oxide.

[0011] The preparation temperature is usually 100°C when carried out in the gas phase.
A suitable temperature is 500°C to 500°C, preferably 200 to 450°C, and when carried out in a liquid phase, a temperature of usually 0 to 200°C, preferably room temperature to 120°C.

[0012] The reaction is preferably carried out in a liquid phase, and inert solvents such as perfluorooctane and perfluorobutyltetrahydrofuran are suitable, but in order to facilitate purification, it is usually carried out without a solvent. preferable.

[0013] The amount of catalyst is usually 0.01 to 50% relative to the raw material.
% by weight, preferably from 0.1 to 10% by weight. The reaction temperature is usually -40 to 200°C, preferably -10 to 100°C.
The temperature range is ℃, and the reaction pressure is 0 to 20 kg/cm.
2 (gauge pressure) is appropriate, especially 0 to 10 kg/c
m2 (gauge pressure) is preferred.

Fluorination of R223 obtained by this reaction can be carried out using hydrogen fluoride in the gas phase or liquid phase in the presence of a catalyst. Catalysts used in gas phase systems include, but are not limited to, Al, Cr, Mg, and C.
A halide, oxide, or halogenated oxide containing at least one element selected from the group consisting of a, Ba, Sr, Fe, Ni, Co, and Mn can be used.

[0015] As a method for preparing the catalyst, any method can be employed as long as it can homogeneously disperse a halide, oxide, or halogenated oxide containing at least one element selected from the above ten elements. It is.

[0016] Examples include coprecipitation method and kneading method. Particularly preferred is a method in which a hydrate is coprecipitated from an aqueous solution of a salt of the metal element, or a method in which a hydroxide cake is kneaded and ground using a ball mill, homogenizer, or the like. As the hydroxide, any of those precipitated from an aqueous solution of inorganic salts such as nitrates and sulfates using aqueous ammonia or urea, and those prepared by hydrolysis of organic salts can be used.

[0017] The catalyst in the hydrate state has a molecular weight of 120-15
After drying at 0°C, usually 300-600°C, preferably 3
It is preferable to bake at 50 to 450°C.

[0018] It is desirable to activate the catalyst in the fluorination of R223, and the purpose can be achieved by performing the fluorination treatment usually at a temperature of 100 to 450°C, preferably 200 to 350°C. Activation may also be carried out within the fluorination reaction system or by heat treatment with a fluorinated hydrocarbon.

[0019] Gas phase fluorination of R223 is carried out at normal pressure or under elevated pressure at 150-550°C, particularly preferably at 250-550°C.
Suitably, the temperature range is 450°C. The proportions of hydrogen fluoride and starting materials can vary widely. However, stoichiometric amounts of hydrogen fluoride are usually used to replace the chlorine atoms. Considerably more than the stoichiometric amount of hydrogen fluoride may be used, for example four times the mole or more, relative to the total number of moles of starting materials. Contact time is usually 0.1-3
00 seconds, particularly preferably 5 to 30 seconds.

Catalysts used in the liquid phase fluorination of R223 include halides such as Sb, Nb, Ta, Sn, etc., such as SbF5, SbCl5, SbCl2 F3, N
bCl5, NbF5, TaF5, TaCl5,
Fluorination catalysts such as SnCl4 can be used.

[0021] The liquid phase fluorination reaction is suitably carried out at a temperature range of 0 to 200°C, particularly preferably room temperature to 150°C, under normal pressure or increased pressure. The reaction is usually carried out without a solvent, but a solvent may be used, and the solvent used in this case is not particularly limited as long as it dissolves the raw material propane and the solvent itself is less fluorinated than the raw material. However, it is usually appropriate to carry out the reaction at 0 to 10 kg/cm2 (gauge pressure), and when a solvent is used, the reaction pressure varies depending on the type of solvent, etc.

Hydrogen fluoride may be charged in advance before the reaction, but it is preferable to blow it into the liquid phase during the reaction.

[0023]

[Examples] Examples of the present invention will be shown below. [Preparation Example 1] 1200g of Cr(NO3)3.9H
2 O and 100 g of Mg(NO3)2 6H2 O
was dissolved in 2.5 liters of water, and this and 2000 g of 28% by weight ammonia water were added to 4 liters of heated water with stirring to obtain a hydroxide precipitate. After filtering this, washing with pure water, and drying, 450
The mixture was calcined at ℃ for 5 hours to obtain an oxide powder. This was molded into a cylindrical shape with a diameter of 5 mm and a height of 5 mm using a tablet molding machine. The catalyst thus obtained was activated by fluorination at 200 to 400° C. in a hydrogen fluoride/nitrogen mixed gas stream before the reaction.

[Preparation Example 2] 1100 g of special grade reagent Al (
NO3 )3 ・9H2 O, 125g Cr(NO3
)3 ・9H2 O and 40g Mg(NO3)2
・Dissolve 6H2O in 2.5 liters of water and combine it with 2.
2000 g of 8% by weight ammonia water was added to 4 liters of heated water with stirring to obtain a hydroxide precipitate. This was filtered, washed with pure water, and dried, and then calcined at 450° C. for 5 hours to obtain an oxide powder. This was molded into a cylindrical shape with a diameter of 5 mm and a height of 5 mm using a tablet molding machine. The catalyst thus obtained was activated by fluorination at 200 to 400° C. in a hydrogen fluoride/nitrogen mixed gas stream before the reaction.

[Preparation Example 3] Commercially available γ-alumina 100
After drying 0 g to remove water, it was fluorinated at 300 to 450°C in a hydrogen fluoride/nitrogen mixed gas flow, and then further chlorinated and fluorinated at 250 to 300°C in an R11 gas flow.

[Preparation Example 4] Commercially available γ-alumina 100
0g of tantalum pentaethoxide (Ta(OEt)
5) was impregnated with a solution dissolved in 2 liters of ethanol, dried to remove the solvent, and further soaked in 60 g of ethanol.
It was fired at 0°C. Next, in the R11/nitrogen mixed gas stream, 1
It was activated by chlorination and fluorination at 00 to 300°C.

[Example 1] 10 liters of Hastelloy C
0.5 kg of anhydrous aluminum chloride (
After adding 3.7 mol) and degassing under reduced pressure, 8 kg (60.2 mol) of 1,1-dichlorodifluoroethylene was added. After cooling the autoclave to 0°C, R21 was continued to be added while maintaining the reaction temperature between 0 and 10°C. R21
After adding 6 kg (58.3 mol) of
, R223ab5.1%, R223ca 76.2
%, R223cb 1.7%, other 1.2%) is 1
3 kg was obtained (yield 92%).

Next, a U-shaped reaction tube made of Inconel 600 with an inner diameter of 2.54 cm and a length of 100 cm was used as a fluorination reactor, and 200 cm of the fluorination catalyst prepared as shown in Preparation Example 1 was added.
Filled with 0ml. The reactor was heated to 280° C. and gasified R223 was supplied at a rate of 160 ml/min and hydrogen fluoride was supplied at a rate of 640 ml/min to advance the reaction. The crude reaction gas was passed through an alkaline aqueous layer to recover a crude liquid.

By distilling and purifying the reaction crude liquid, R2
7.2 kg of 25cb (1,3-dichloro-1,1,2,2,3-pentafluoropropane) was obtained (yield: 6
5%).

[Example 2] 10 liters of Hastelloy C
0.5 kg of anhydrous zirconium tetrachloride in an autoclave
After adding (2.1 mol) and degassing under reduced pressure, 1,1-
8 kg (60.2 mol) of dichlorodifluoroethylene
) was added. After cooling the autoclave to 0°C, R21 was continued to be added while maintaining the reaction temperature between 0 and 10°C. R
After adding 6 kg (58.3 mol) of 21, stirring was continued for another 1 hour, the reaction solution was filtered, and the crude reaction solution was purified by distillation.
%, R223ab5.1%, R223ca 76.
2%, R223cb 1.7%, others 1.2%)
13 kg of was obtained (yield 92%).

Next, a U-shaped reaction tube made of Inconel 600 with an inner diameter of 2.54 cm and a length of 100 cm was used as a fluorination reactor, and 200 cm of the fluorination catalyst prepared as shown in Preparation Example 1 was added.
Filled with 0ml. The reactor was heated to 280° C. and gasified R223 was supplied at a rate of 160 ml/min and hydrogen fluoride was supplied at a rate of 640 ml/min to advance the reaction. The crude reaction gas was passed through an alkaline aqueous layer to recover a crude liquid.

By distilling and purifying the reaction crude liquid, R2
8.3 kg of 25cb was obtained (yield 74%).

[Example 3] 10 liters of Hastelloy C
0.5 kg of anhydrous zirconium tetrachloride in an autoclave
After adding (2.1 mol) and degassing under reduced pressure, 1,1-
8 kg (60.2 mol) of dichlorodifluoroethylene
) was added. After cooling the autoclave to 0°C, R21 was continued to be added while maintaining the reaction temperature between 0 and 10°C. R
After adding 6 kg (58.3 mol) of 21, stirring was continued for another 1 hour, the reaction solution was filtered, and the crude reaction solution was purified by distillation to obtain R223 (molar ratio; R223aa 4.2%).
, R223ab 6.1%, R223ca 87.0
%, R223cb 0.1%, other 2.6%) is 1
3 kg was obtained (yield 92%).

Next, a U-shaped reaction tube made of Inconel 600 with an inner diameter of 2.54 cm and a length of 100 cm was used as a fluorination reactor, and 200 cm of the fluorination catalyst prepared as shown in Preparation Example 2 was added.
Filled with 0ml. The reactor was heated to 320° C. and gasified R223 was supplied at a rate of 160 ml/min and hydrogen fluoride was supplied at a rate of 640 ml/min to advance the reaction. The crude reaction gas was passed through an alkaline aqueous layer to recover a crude liquid.

By distilling and purifying the reaction crude liquid, R2
7.6 kg of 25cb was obtained (yield 68%).

[Example 4] 10 liters of Hastelloy C
After adding 0.5 kg of the catalyst prepared as shown in Preparation Example 3 to a prepared autoclave and degassing under reduced pressure, 8 kg (60.2 mol) of 1,1-dichlorodifluoroethylene was added. After cooling the autoclave to 0°C, R21 was continued to be added while maintaining the reaction temperature between 0 and 10°C. After adding 6 kg (58.3 mol) of R21, stirring was continued for another 1 hour, the reaction solution was filtered, and the crude reaction solution was purified by distillation to obtain R223 (molar ratio; R223aa 5.3%, R2
23ab 5.7%, R223ca 86.1%, R
223cb 0.6%, others 2.3%) 12 kg were obtained (yield 87%).

Next, a U-shaped reaction tube made of Inconel 600 with an inner diameter of 2.54 cm and a length of 100 cm was used as a fluorination reactor, and 200 cm of the fluorination catalyst prepared as shown in Preparation Example 2 was added.
Filled with 0ml. The reactor was heated to 320° C. and gasified R223 was supplied at a rate of 160 ml/min and hydrogen fluoride was supplied at a rate of 640 ml/min to advance the reaction. The crude reaction gas was passed through an alkaline aqueous layer to recover a crude liquid.

By distilling and purifying the reaction crude liquid, R2
7.0 kg of 25cb was obtained (yield 68%).

[Example 5] 10 liters of Hastelloy C
After adding 0.5 kg of the catalyst prepared as shown in Preparation Example 4 to a prepared autoclave and degassing under reduced pressure, 8 kg (60.2 mol) of 1,1-dichlorodifluoroethylene was added. After cooling the autoclave to 0°C, R21 was continued to be added while maintaining the reaction temperature between 0 and 10°C. After adding 6 kg (58.3 mol) of R21, stirring was continued for another 1 hour, the reaction solution was filtered, and the crude reaction solution was purified by distillation.
23ab 5.1%, R223ca 87.0%, R
223cb 0.5%, other 2.4%) is 10kg
(yield 73%).

Next, a U-shaped reaction tube made of Inconel 600 with an inner diameter of 2.54 cm and a length of 100 cm was used as a fluorination reactor, and 200 cm of the fluorination catalyst prepared as shown in Preparation Example 2 was used.
Filled with 0ml. The reactor was heated to 320° C. and gasified R223 was supplied at a rate of 160 ml/min and hydrogen fluoride was supplied at a rate of 640 ml/min to advance the reaction. The crude reaction gas was passed through an alkaline aqueous layer to recover a crude liquid.

By distilling and purifying the reaction crude liquid, R2
5.6 kg of 25cb was obtained (yield 65%).

[0042]

As shown in the examples, the present invention has the effect that dichloropentafluoropropane (R225), which has been difficult to obtain in high purity, can be produced in high yield. Moreover, R225cb in R225 can be obtained with high selectivity.

Claims (1)

[Claims] 1. Dichloropentafluoropropane, which is characterized in that dichlorofluoromethane is added to 1,1-dichlorodifluoroethylene to produce tetrachlorotrifluoropropane, which is then fluorinated to obtain dichloropentafluoropropane. How to make propane.