The catalyst for the fluorination of the lower aliphatic galoidovodorodov and method of fluorination of the lower aliphatic galoidovodorodov

 

(57) Abstract:

Use: production of catalysts for fluorination. The inventive catalyst is a partially fluorinated amorphous chromium oxide with a specific surface area of not less than 170 m2/g Catalyst was prepared by precipitation of chromium hydroxide from an aqueous solution of chromium nitrate aqueous solution of ammonia. The precipitate is dried. Then pressed into pellets and is sintered. The obtained amorphous chromium oxide foryouth hydrogen fluoride to fluoride content of at least 8 wt. fluorine. Reagent 1: lower aliphatic galoidovodorodov, preferably trichloroethylene or 1,1,1-tryptophanate. Reagent 2: HF. Reaction conditions: at 290 to 380°C. 2 S. and 3 C. p. F.-ly, 3 ill.

The invention relates to the fluorination catalyst and to a method of fluorination of halogenated derivatives of hydrocarbons in the gas phase in the presence of a fluorination catalyst.

Fluorinated halogenated derivatives of hydrocarbons, such as 1,1,1,2 - Tetrafluoroethane, useful as a substitute fluorocarbons, and their use as refrigerants, speciatly, aerosol products, cleaners, etc.

As the fluorination catalyst known oxide of Hali chromium or partially fluorinated chromium oxide, which can be supported on a carrier [2]

Also known catalyst containing chromium oxide and an additive, such as NaF [3] Mg or Ba [4] the transition metal [5] or AlPO4[6] there are also Known methods using a catalyst containing metallic chromium [7] or a metal other than chromium [8]

In U.S. patent [9] described the reaction of fluorination, which is used partially fluorinated aluminum oxide.

Known liquid-phase fluorination reaction, which is used as a catalyst antimony. In addition, the known liquid-phase fluorination reaction, which is used as a catalyst fluoride of an alkali metal [10]

As the halogen derivatives of hydrocarbons using a different connection. Fluoridation explained, making reference to the preparation of 1,1,1,2-Tetrafluoroethane (hereinafter referred to "134a") when the fluorination of trichloroethylene or 1,1,1-tetrafluorochloroethane (hereinafter referred to as a").

Unprofitable to synthesize 134a and a by liquid-phase reactions from the point of view of a low degree of conversion and the material of the reactor. If the fluorination reaction is carried out in the gas phase, the degree of transformation a in 134a low due to the equilibrium. Therefore, the catalyst should Apollo lifetime and good selectivity in industrial use. Extending the lifetime of the catalyst avoids frequent changes of the catalyst and reduces the cost of the catalyst.

The lifetime of the catalyst can be increased by adding chlorine gas [11] or gaseous oxygen [12] to the reaction gas mixture. If add gaseous chlorine, the choice of the material of the reactor may be limited and you should also consider the increase in output products. If add gaseous oxygen, the degree of conversion may be reduced. A known catalyst for the fluorination of chlorinated aliphatic hydrocarbons, representing the chromium oxide [13]

From the point of view of the above, it is advantageous to provide a catalyst which has a long lifetime. If such a catalyst has high catalytic activity, it is not only the cost of the catalyst, but also the size of the reactor, which is made from high quality expensive material can be advantageously reduced.

One aspect of the present invention is to provide a new catalyst for fluorination, which can effectively catalyze the fluoridation of halogen derivatives of hydrocarbons.

Another aspect of the invention is one which aspect of the present invention proposed a catalyst, fluoridation containing chromium oxide with a specific surface area of at least 170 m3/,

According to the second aspect of the present invention, a method for fluorination of halogenated derivatives of hydrocarbons in the presence of the specified catalyst fluorination.

The chromium oxide is used as catalyst, according to the present invention is preferably amorphous. Here, the term "amorphous" means that there is no significant peaks in x-ray analysis of chromium oxide. Preferably, the chromium oxide was partially fluorinated.

According to the invention when the control properties of the catalyst in certain stages of preparation, you can get a fluorination catalyst having a high activity and long lifetime, and high productivity as compared with the known catalysts. The catalyst can be activated oxygen-containing gas such as air.

In preferred embodiments of the invention the composition of the chromium oxide is as follows: if the chromium oxide expressed by the formula Cr2O3nH2O, then n is not more than 3, preferably from 1 to 1.5. In the oxide of chromium atomic ratio of oxygen and chromium not more than 3:1, predpochtitel can be prepared as follows.

First, for the preparation of chromium hydroxide is mixed aqueous solution of a chromium salt (e.g., chromium nitrate, chromium chloride, chromecacheview alum, chromium sulfate, etc.,) and aqueous ammonia. For example, 5.7% of the resultant aqueous solution of chromium nitrate is added dropwise from 1 to 1.2 equivalents. 10% aqueous ammonia solution. Properties of chromium hydroxide can be controlled by selection of the reaction rate of cooking. The higher the reaction rate, the better. The reaction rate depends on the temperature of the reaction system, a method of mixing an aqueous solution of ammonia (i.e., mixing speed, mixing conditions, etc.,

Phase precipitate the chromium hydroxide is dried, for example, in air at a temperature of from 70 to 200aboutWith, in particular about 120aboutWith over 1 to 100 hours, in particular about 12 o'clock the Catalyst at this stage is called "the catalyst in a state of chromium hydroxide". This catalyst grind into powder with size of 1 mm or less. The amount of powder having a particle size of from 86 to 1000 μm, preferably about 95% the Speed of response preparation are selected so that the density of the powder ranged from 0.6 to 1.1 g/ml, preferably from 0.6 to 1.09 g/ml If the density of the powder is less than 0.6 A catalyst of low activity.

The specific surface of the powder is at least 100 m2/g, preferably at least 120 m2/g after obezvozhivanija at 200aboutWith over 80 minutes, the Upper limit of the specific surface of the powder is preferably 220 m2/,

Powder of chromium hydroxide, which contains optional 3 wt. or less of graphite, granularit using a granulator. Preferably, the pellet has a diameter of 3.0 mm and a height of 3.0 mm and the pressure crushing (i.e., the strength of granules) 210 40 kg/cm2. If the pressure is crushing too high, the efficiency of contact with the gas, and the activity of the catalyst decreases, and the granules become legkorastvorimyh. If the pressure is crushing too small, the granules are easily crushed, so that manipuliruemoy with granules deteriorating.

Educated catalyst then is sintered in an atmosphere of inert gas, for example in a stream of nitrogen to obtain amorphous chromium oxide. The sintering temperature is typically at least 360aboutC. But as too high sintering temperature to cause crystallization of chromium oxide, the sintering temperature should be the highest in the temperature range to With, in particular at a temperature of approximately 400aboutWith over 1 to 5 hours, particularly in a period of about 2 hours Agglomerated catalyst has a specific surface area of at least 170 m2/g, preferably at least 180 m2/g, more preferably at least 200 m2/, the Upper limit of the specific surface of the catalyst is not critical. If the specific surface is less than 170 m2/g, the catalyst will have insufficient activity.

The catalyst preferably foryouth and it is treated with hydrogen fluoride. The fluorination is carried out at a temperature at which water is condensed, for example about 150aboutC and a pressure of 1 ATM, but not higher than the temperature at which the catalyst is crystallized by the heat of reaction. It is desirable that the temperature of fluorination was from 100 to 460aboutC. the Pressure is not limited. Preferred is the same pressure as in the catalytic reaction. If the catalyst is not fluorinated, hydrogen fluoride will react with the catalyst, and the desired reaction is strongly inhibited.

The fluorination catalyst effectively as the content of fluorine in the catalyst does not reach for the crane to be at least 15 wt. The upper limit of the content of fluorine is usually 48 wt. The specific surface can be reduced when fluoridation.

The method according to the invention can be fluoridate various halogenated derivatives of hydrocarbons. Typical examples of halogen derivatives of hydrocarbon is trichloroethylene, 1,1,1-tryptophanate (a), carbon tetrachloride, chloroform, dichloromethane, harmatan, 1,1,1-trichloroethane, trichlorotrifluoroethane (a, 113), CF3CHCl2(123), CF3CHClF (124), perchloroethylene (CCL2=CCl2), etc.

The products obtained by the method according to the invention, the following:

1,1,1,2-Tetrafluoroethane )134a) of 1,1,1-tryptophanate

114 from CCl2=CCl2or 113

115 from CCl2=CCl2113, a or 118a

124 from CCl2=CCl2or 123

125 from CCl2=CCl2, 123 or 124

32 from dichloromethane or chloroformate

41 from chloromethane

11 of CCl4< / BR>
12 of CCl4or CF3Cl

141b of 1,1,1-trichloroethane,

142b of 1,1,1-trichloroethane or 141b

143a of 1,1,1-trichloroethane or 142b

One example of a reaction which takes place under the proposed method, the following:

CF3CH2Cl +HF ->> CF3CH2F + HCl

The molar ratio of hydrogen chloride and galogenoproizvodnykh fluoride carbon and halogen derivatives of hydrocarbons is from 0.9:1 to 16:1, the reaction temperature is usually from 80 to 450aboutC. Preferred pressure depends on the type of reaction.

For example, in the reaction for the preparation of 134a from a the degree of transformation and the lifetime of the catalyst can be selected by changing the molar ratio of hydrogen fluoride and a and the reaction temperature. The preferred molar ratio of hydrogen fluoride and a is from 0.9:1 to 10:1 and the preferred reaction temperature from 290 to 380aboutC. the Preferred pressure is atmospheric reactions. At high pressure the activity of the catalyst may decrease.

P R I m e R s of the invention.

In the following examples and comparative examples a contact with hydrogen fluoride to prepare 134a.

As the reaction tube using the tube Hasteloy C having an inner diameter of 15 mm

In examples 1-3 and comparative examples 1-3 catalyst granular and pulverized into powder having a particle size of from 300 to 1000 μm.

In the examples and comparative examples compare the catalytic activity, selectivity, lifetime of the catalyst, and performance. If not specifically defined, under the activity of the catalyst, the time is yet a maximum achievable conversion (in)

the lifetime of the catalyst represents the time (in hours) for which the degree of conversion reaches 60% of the maximum value;

productivity refers to the amount of the reaction product (134a) produced per 1 l of catalyst for 1 h

P R I m e R 1. To 5.7% of the resultant aqueous solution of chromium nitrate (765 kg) is added 10% aqueous ammonia solution (114 kg). The precipitate is collected by filtration and dried in air at 120aboutC for 12 h to obtain the chromium hydroxide. The chromium oxide pressed to obtain pellets with a diameter of 3.0 mm and a height of 3.0 mm, and is sintered at 400aboutC for 2 h to obtain an amorphous oxide of chromium. Then, the amorphous chromium oxide foryouth fluoride hydrogen at 200aboutC for 2 hours to obtain a catalyst containing a 15.6 wt. fluorine.

The chromium hydroxide and amorphous chromium oxide have the following properties:

The chromium hydroxide

The density of the powder 0,80 g/ml

The strength of granules 241 kg/cm2< / BR>
Specific surface area of 180 m2/g

The chromium oxide

The specific surface 241 m2/g

Using the catalyst in the form of amorphous chromium oxide fluorination a carried out under the following conditions:

The molar ratio of HF:133a) 9:1

Those who and W to the flow rate (F)

Catalytic activity 26,9%

Comparative example 1. Analogously to example 1, but when conditions change, obtain sediment: 5.7 wt.-aqueous solution of chromium nitrate (255 kg), 10% aqueous ammonia solution (38 kg) and added to 9 min 45 s, prepare the catalyst. The chromium hydroxide and chromium oxide have the following properties:

The chromium hydroxide

The density of the powder 1,19 g/ml

The strength of granules 93 kg/cm2< / BR>
The specific surface 79 m2/g

The chromium oxide

The specific surface 126 m2/g

A foryouth the same way as in example 1 but using the above chromium oxide. The catalytic activity of 7.4%

P R I m m e R 2. The catalyst is prepared as follows. To 5.7 wt.-the resultant aqueous solution of chromium nitrate (25,5 kg) add 10 wt.-aqueous ammonia solution (3.8 kg) at 50aboutC. Then the catalyst was prepared in the same manner as in example 1. The chromium hydroxide and chromium oxide have the following properties:

The chromium hydroxide

The density of the powder of 0.67 g/ml

The strength of granules 178 kg/cm2< / BR>
The specific surface 141 m2/g

The chromium oxide

The specific surface 221 m2/g

If a foryouth at a molar ratio of 9:1, the reaction temperature 350aboutYarnykh ratio of 1:1, the reaction temperature 350aboutAnd with time contact is 0.4, the lifetime of the catalyst is 115 PM

Comparative example 2. The catalyst prepared as in example 2, but modified to 33aboutWith the temperature of deposition. The chromium hydroxide and chromium oxide have the following properties:

The chromium hydroxide

The density of the powder of 0.53 g/ml

The strength of granules 303 kg/cm2< / BR>
The specific surface 134 m2/g

The chromium oxide

The specific surface 154 m2/g

A foryouth the same way as in example 2, but using the above chromium oxide. The catalytic activity of 16.5% and the lifetime of the catalyst 89 h

P R I m e R 3. To 5,9 resultant aqueous solution of chromium chloride (16.5 kg) add 10% ammonia solution (3.2 kg) at 50aboutC. Then, just as in example 1 to prepare a catalyst. The chromium hydroxide and chromium oxide have the following properties:

The chromium hydroxide

The density of the powder of 0.62 g/ml

The strength of granules 246 kg/cm2< / BR>
The specific surface 158 m2/g

The chromium oxide

The specific surface 228 m2/g

If a foryouth at a molar ratio of 9:1, the reaction temperature 350aboutWith and eventually contact 0,5, catalytic Akti is about time contact 0,40 then the lifetime of the catalyst is 106 hours

Comparative example 3. The catalyst prepared as in example 3, but modified to 33aboutWith the temperature of deposition. The chromium hydroxide and chromium oxide have the following properties:

The chromium hydroxide

The density of the powder of 0.41 g/ml

The granule strength of 220 kg/cm2< / BR>
Specific surface area of 48 m2/g

The chromium oxide

The specific surface 122 m2/g

A foryouth the same way as in example 3, but using the above chromium oxide. The catalytic activity of 6.7% and the lifetime of the catalyst 80 hours

P R I m e R 4. Use the same catalyst as in example 2, only in the form of granules, foryouth a at a molar ratio of 4:1, the reaction temperature 350aboutC at 1 ATM with a degree of conversion of 20% Selectivity is 91.2% of space velocity (SV) 4557/h and performance 1076 g/l catalyst/h

Comparative example 4. Example carried out analogously to example 4, but using a chromium oxide without media (described in example 1, the United Kingdom patent GB 1589924 or in Japanese patent Japanese Patent Kokai Publication No. 105404/1978), foryouth a. The selectivity of 91% SV 500/h and the performance of 82.9 g/l catalyst/h

P R I m e R 5. Using the same catalyst as in example 2, but in the form of gr the value of 20.3% Selectivity to 95.7% SV 2250/h and the performance of 483 g/l catalyst/h

Comparative example 5. Example carried out analogously to example 5, but using the chromium oxide on the media (described in example 1 W 089/10341) foryouth a. Selectivity 94,3% SV 101/h and a capacity of 15.6 g/l catalyst/h

P R I m e R 6. Using catalysts in the form of a granulated form of chromium oxide having different specific surface, foryouth a using chlorine fluoride at a molar ratio of 9:1, the reaction temperature 350aboutAnd with the time of contact of 0.5, and alter the catalytic activity. The results are shown in Fig.1.

In this example and subsequent examples, the catalytic activity is defined as the rate of the reaction at 350aboutC. the Amount of catalytic activity present in the form of relative values.

P R I m e R 7. Using catalysts in the form of a granulated form of chromium oxide, which is prepared from chromium hydroxide with different densities of powder, foryouth a with hydrogen fluoride in a molar ratio of 9: 1, the reaction temperature 350aboutAnd with the time of contact of 0.5, and measure the catalytic activity. The results are shown in Fig.2.

P R I m e R 8. Using catalysts in the form of a granulated form oxide XP is and hydrogen at a molar ratio of 9: 1, the reaction temperature 350aboutAnd with the time of contact of 0.5, and measure the catalytic activity. The results are shown in Fig.3.

1. The catalyst for the fluorination of the lower aliphatic galoidovodorodov representing amorphous chromium oxide, characterized in that it contains partially fluorinated chromium oxide with a specific surface area of not less than 170 m2/,

2. Method of fluorination of the lower aliphatic galoidovodorodov in the gas phase at elevated temperature in the presence of a catalyst of amorphous chromium oxide, characterized in that the catalyst used partially fluorinated chromium oxide with a specific surface area of not less than 170 m2/,

3. The method according to p. 2, characterized in that the use of partially fluorinated chromium oxide containing at least 8 wt. fluorine.

4. The method according to p. 2, characterized in that as galoidovodorodov use trichloroethylene or 1,1,1-tryptophanate.

5. The method according to p. 2, wherein the process is conducted at 290 - 380oC.

 

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