JP4399790B2 - Propylene production method - Google Patents

Description

  The present invention relates to a method for producing propylene using dimethyl ether as a raw material.

  Propylene has been separated and refined from petroleum cracked gas, but natural gas is temporarily converted to methanol and dimethyl ether for ease of separation and purification, and technology for producing propylene in the consuming area is attracting attention. is there.

As catalysts for converting methanol and dimethyl ether to lower olefins such as propylene, a catalyst in which magnesium phosphate is supported on an aluminosilicate zeolite (Patent Document 1), an alkaline earth metal-modified alkaline earth metal-containing zeolite catalyst (Patent Document 2) Alkaline earth metal-containing aluminophosphosilicate (Patent Document 3) and pentasil-type aluminosilicate having an Si / Al atomic ratio of at least 10 (Patent Document 4) are known.

Japanese Unexamined Patent Publication No. 64-31733 Japanese Unexamined Patent Publication No. 64-50827 JP-A-64-51316 JP-A-4-217828

  Among the various catalysts described above, the pentasil-type aluminosilicate catalyst has a structure that is uniform in size and has straight pores connected three-dimensionally, so that the precipitation of carbonaceous material is unlikely to occur. Therefore, long-term stability (long life) of the catalyst is expected. In addition, it has a relatively strong solid acid property and is excellent in terms of high thermal stability at high temperatures.

  In the method for producing propylene from dimethyl ether using this pentasil-type crystalline aluminosilicate as a catalyst, the reaction proceeds over a temperature of 280 to 700 ° C., but a higher reaction rate is obtained at a higher temperature.

However, pentasil-type crystalline aluminosilicates gradually start to disintegrate at high temperatures, and as a result, the catalyst performance deteriorates, so that high reaction results cannot be maintained for a long time. At high temperatures, the production of coke (carbonaceous material) becomes prominent, and this coats or accumulates the surface of the pentasil-type crystalline aluminosilicate, resulting in a rapid decrease in catalytic activity.

  An object of the present invention is to provide a method capable of efficiently producing propylene from dimethyl ether using a catalyst in which zirconium oxide is supported on a pentasil type aluminosilicate, maintaining high catalytic activity even at high temperatures.

  As a result of intensive studies to solve the above problems, the present inventor maintains catalytic activity at a higher temperature by treating a catalyst in which zirconium oxide is supported on a pentasil-type aluminosilicate with a phosphoric acid aqueous solution and / or a sulfuric acid aqueous solution. The inventors have found that propylene can be efficiently produced from dimethyl ether, and have completed the present invention.

That is, in the present invention, when propylene is produced by contacting dimethyl ether with a catalyst in the gas phase, zirconium oxide is supported on a pentasil type aluminosilicate having a molar ratio of SiO ₂ / Al ₂ O ₃ of 20 to 250 as the catalyst. Further, the present invention relates to a method for producing propylene, characterized by using a catalyst obtained by further treating with a phosphoric acid aqueous solution and / or a sulfuric acid aqueous solution.

  By the method of the present invention, propylene can be produced from dimethyl ether in a high yield over a long period of time.

The catalyst used in the method of the present invention is a pentasil type aluminosilicate supporting zirconium oxide. This pentasil type is a kind of zeolite and hydrothermal synthesis using an alkylammonium cation as a template. Is a crystalline substance produced by The characteristics of the pentasil type are (1) pore diameter defined by an oxygen 10-membered ring, (2) strong solid acid properties, and (3) high silica composition (high Si / Al atomic ratio). . Two types of pores with a diameter of 0.53 x 0.56 nm and 0.51 x 0.55 nm derived from the crystal structure are three-dimensionally connected, and have a pore diameter slightly larger than the diameter of the benzene ring. Yes. Moreover, it has strong solid acidity in zeolite. It is easy to synthesize zeolite with high crystallinity and high silica composition. The Si / Al atomic ratio is usually as high as 12 to 500, and since the Al concentration is small, the acid density is low. In addition, it is hydrophobic, has high thermal stability and high durability against high-temperature water vapor. The shape selectivity based on the size of pores composed of a 10-membered oxygen ring is also a major feature. For this reason, it is used as a solid acid catalyst and catalyst carrier for various industrial reactions.
This pentasil type aluminosilicate is commercially available.

The ratio of SiO ₂ / Al ₂ O ₃ of aluminosilicate suitable for this catalyst is about 20 to 250 in molar ratio, and preferably about 30 to 150. The average particle size is suitably about 0.1 to 10 mm.

  The supporting effect of zirconium oxide is to maintain activity at high temperature and to improve selectivity. The method for supporting zirconium oxide on a pentasil type aluminosilicate is not particularly limited, and a precipitation method, a kneading method, and an impregnation method can be used. For example, it is possible to suspend a pentasil-type aluminosilicate powder in an aqueous solution of a water-soluble zirconium compound and add an alkali to fold the zirconium compound on the surface of the aluminosilicate particles. This zirconium compound may be changed in oxide by a conventional method such as firing in an oxygen atmosphere.

  The ratio of the aluminosilicate and zirconium oxide in the catalyst is about 10/90 to 99/1, preferably about 20/80 to 97/3 by weight. The catalyst can contain a third component for various purposes.

  The treatment effect is in improving activity and selectivity. The treatment of the catalyst with an aqueous phosphoric acid solution and / or an aqueous sulfuric acid solution can be performed by bringing the catalyst into contact with an aqueous phosphoric acid solution and / or an aqueous sulfuric acid solution. This contact may be performed, for example, at room temperature for 10 to 60 minutes. By performing the treatment as described above, the activity and selectivity of the catalyst are improved.

The concentration of the phosphoric acid aqueous solution is preferably about 0.1 to 3M, particularly about 0.3 to 2M, and the concentration of the sulfuric acid aqueous solution is preferably about 0.01 to 2M, particularly about 0.05 to 1.5M. The amount of phosphoric acid and / or sulfuric acid used is about 0.1 to 20% by weight, preferably about 0.2 to 15% by weight, based on the total weight of zirconium oxide and aluminosilicate. When both are included, the sum of both is about 0.1 to 30% by weight.
This amount is the amount remaining in the catalyst after treatment as phosphoric acid or sulfuric acid (both free and salt forms), and both phosphoric acid and sulfuric acid must be acid.

  The removal of moisture may be left as it is, but is preferably heated.

  Baking is performed after moisture removal. This firing may be performed at 110 to 150 ° C. for about 5 to 40 hours in an oxygen atmosphere such as air.

  After calcination, if necessary, it can be pressure-molded, pulverized, and classified to obtain a catalyst having a desired particle size.

Propylene is produced by contacting the catalyst with dimethyl ether in the gas phase. The reaction temperature is about 300 to 650 ° C., preferably about 350 to 600 ° C., the pressure is about 0.1 to 50 kg / cm ² · G, preferably about 0.5 to 30 kg / cm ² · G, and the contact time (W / F) is suitably about 1 to 40 g-cat · h / mol.

  Dimethyl ether may be fed as it is, but it is preferable to dilute and feed DHE with an inert gas such as nitrogen, carbon dioxide, hydrogen, etc., since the supply rate can be made uniform.

I. Preparation of catalyst 1) Catalyst number (1)
Distilled water about 400ml oxide zirconium chloride octahydrate (ZrOCl ₂ · 8H ₂ O) was dissolved 1.57 g, this pentasil-type crystalline aluminosilicate (Chemie _{Ltd., SiO 2 / Al 2 O 3} = 83. (7, average particle size 0.5 mm) was added, and the mixture was stirred at 80 ° C. for 2 hours and left to reach room temperature. Next, 2.5M aqueous ammonia solution was added dropwise to the mixture until the pH reached 9, and the mixture was stirred at room temperature for 2 hours, and then the produced solid product was filtered and washed. 2 g of the obtained solid was dried at 120 ° C. for 24 hours, added to 20 ml of 1M phosphoric acid aqueous solution, and stirred at room temperature for 30 minutes. Thereafter, this was dried at 120 ° C. for a whole day and night and then calcined in air at 500 ° C. for 3 hours. Further, the obtained powder was pressure-molded and then pulverized and classified to 20 to 40 mesh to obtain the desired catalyst (1).

2) Catalyst number (2)
Distilled water about 400ml oxide zirconium chloride octahydrate (ZrOCl ₂ · 8H ₂ O) was dissolved 0.52 g, this pentasil-type crystalline aluminosilicate (Chemie _{Ltd., SiO 2 / Al 2 O 3} = 83. 7) After charging 3.8 g, the mixture was stirred at 80 ° C. for 2 hours and left to reach room temperature. Next, 2.5M aqueous ammonia solution was added dropwise to the mixture until the pH reached 9, and the mixture was stirred at room temperature for 2 hours, and then the produced solid product was filtered and washed. 2 g of the obtained solid was dried at 120 ° C. for a whole day and night, added to 20 ml of 1M phosphoric acid aqueous solution, and stirred at room temperature for 30 minutes. Thereafter, this was dried at 120 ° C. for a whole day and night and then calcined in air at 500 ° C. for 3 hours. Further, the obtained powder was pressure-molded and then pulverized and classified to 20 to 40 mesh to obtain the desired catalyst (2).

3) Catalyst number (3)
Distilled water about 400ml oxide zirconium chloride octahydrate (ZrOCl ₂ · 8H ₂ O) was dissolved 5.23 g, this pentasil-type crystalline aluminosilicate (Chemie _{Ltd., SiO 2 / Al 2 O 3} = 83. 7) After adding 2.0 g, the mixture was stirred at 80 ° C. for 2 hours and left to reach room temperature. Next, 2.5M aqueous ammonia solution was added dropwise to the mixture until the pH reached 9, and the mixture was stirred at room temperature for 2 hours, and then the produced solid product was filtered and washed. 2 g of the obtained solid was dried at 120 ° C. for 24 hours, added to 20 ml of 1M phosphoric acid aqueous solution, and stirred at room temperature for 30 minutes. Thereafter, this was dried at 120 ° C. for a whole day and night and then calcined in air at 500 ° C. for 3 hours. Further, the obtained powder was pressure-molded and then pulverized and classified to 20 to 40 mesh to obtain the desired catalyst (3).

4) Catalyst number (4)
Distilled water about 400ml oxide zirconium chloride octahydrate (ZrOCl ₂ · 8H ₂ O) was dissolved 7.58 g, this pentasil-type crystalline aluminosilicate (Chemie _{Ltd., SiO 2 / Al 2 O 3} = 83. 7) After adding 1.0 g, the mixture was stirred at 80 ° C. for 2 hours and left to reach room temperature. Next, 2.5M aqueous ammonia solution was added dropwise to the mixture until the pH reached 9, and the mixture was stirred at room temperature for 2 hours, and then the produced solid product was filtered and washed. 2 g of the obtained solid was dried at 120 ° C. for 24 hours, added to 20 ml of 1M phosphoric acid aqueous solution, and stirred at room temperature for 30 minutes. Thereafter, this was dried at 120 ° C. for a whole day and night and then calcined in air at 500 ° C. for 3 hours. Further, the obtained powder was pressure-molded and then pulverized and classified to 20 to 40 mesh to obtain the desired catalyst (4).

5) Catalyst number (5)
Distilled water about 400ml oxide zirconium chloride octahydrate (ZrOCl ₂ · 8H ₂ O) was dissolved 1.57 g, this pentasil-type crystalline aluminosilicate (Chemie _{Ltd., SiO 2 / Al 2 O 3} = 83. 7) After adding 3.4 g, the mixture was stirred at 80 ° C. for 2 hours and left to reach room temperature. Next, 2.5M aqueous ammonia solution was added dropwise to the mixture until the pH reached 9, and the mixture was stirred at room temperature for 2 hours, and then the produced solid product was filtered and washed. 2 g of the obtained solid was dried at 120 ° C. for a whole day and night, added to 20 ml of 0.5 M aqueous sulfuric acid solution, and stirred at room temperature for 30 minutes. Thereafter, this was dried at 120 ° C. for a whole day and night and then calcined in air at 500 ° C. for 3 hours. Further, the obtained powder was pressure-molded and then pulverized and classified to 20 to 40 mesh to obtain the desired catalyst (5).

6) Catalyst number (6)
A pentasil-type crystalline aluminosilicate (manufactured by Sud Chemie, SiO ₂ / Al ₂ O ₃ = 83.7) was pressure-molded and then pulverized and classified to 20 to 40 mesh to obtain the desired catalyst (6). .

7) Catalyst number (7)
Distilled water about 400ml oxide zirconium chloride octahydrate (ZrOCl ₂ · 8H ₂ O) was dissolved 1.57 g, this pentasil-type crystalline aluminosilicate (Chemie _{Ltd., SiO 2 / Al 2 O 3} = 83. 7) After adding 3.4 g, the mixture was stirred at 80 ° C. for 2 hours and left to reach room temperature. Next, 2.5M aqueous ammonia solution was added dropwise to the mixture until the pH reached 9, and the mixture was stirred at room temperature for 2 hours, and then the produced solid product was filtered and washed. Thereafter, this was dried at 120 ° C. for a whole day and night and then calcined in air at 500 ° C. for 3 hours. Further, the obtained powder was pressure-molded and then pulverized and classified to 20 to 40 mesh to obtain the desired catalyst (7).

8) Catalyst number (8)
Distilled water of about 400ml was dissolved oxidized zirconium chloride octahydrate the _{(ZrOCl 2 · 8H 2 O)} 7.85g, thereto was added dropwise an aqueous ammonia solution of 2.5M until pH 9, 2 hours at room temperature Stir. Subsequently, the produced solid product was filtered and washed. 2 g of the obtained solid was dried at 120 ° C. for 24 hours, added to 20 ml of 1M phosphoric acid aqueous solution, and stirred at room temperature for 30 minutes. Thereafter, this was dried at 120 ° C. for a whole day and night and then calcined in air at 500 ° C. for 3 hours. Further, the obtained powder was pressure-molded and then pulverized and classified to 20 to 40 mesh to obtain the desired catalyst (8).

II. Reaction Method A reaction tube having an inner diameter of 14 mm and a length of 820 mm was filled with a predetermined amount of the catalyst. A mixed gas having a volume ratio of dimethyl ether and nitrogen of 1: 5 was supplied to the reaction tube so that the contact time (W / F) was 10 g-cat · h / mol, and 450 or 550 ° C. The reaction was carried out at temperature for 2 or 100 hours.
The reaction product and unreacted product obtained by the above operation were analyzed by gas chromatography.

III. Experimental results Experimental results are shown in Tables 1-4.

  Tables 1 to 4 show that under the same reaction temperature and reaction time, the product selectivity of C3 = in the examples is higher than that in the comparative example, and it is found that propylene can be efficiently produced in the present invention. Further, in the examples, even when the reaction temperature is increased from 450 ° C. to 550 ° C., the product selectivity of C3 = does not change, the catalyst performance does not deteriorate, and it can be seen that high catalytic activity is maintained (for example, Example 1 and Example 6). Further, in the examples, even when the reaction time is as long as 2 h → 100 h, the catalyst performance is good without deterioration as in the case of the above reaction temperature (for example, Example 5 and Example 10). On the other hand, in the comparative example, the reaction temperature is 550 ° C. or the reaction time is as high as 100 hours, or the C3 product selectivity is lowered and the catalytic performance is inferior (for example, Comparative Example 1 and Comparative Example 4, Comparison) Example 1 and Comparative Example 7)

  The method for producing propylene of the present invention uses dimethyl ether as a raw material.

Claims (3)

Dimethyl ether is contacted with the catalyst in the gas phase in producing the propylene, zirconium oxide supported on pentasil-type aluminosilicate of 20~250 SiO ₂ / Al ₂ O ₃ is in a molar ratio as the catalyst, this re down A method for producing propylene, characterized by using a catalyst calcined in a state containing and contacting an aqueous acid solution and / or an aqueous sulfuric acid solution Zirconium oxide is supported at a ratio of 20/80 to 97/3 by weight ratio of aluminosilicate / zirconium oxide, contact is performed with an aqueous phosphoric acid solution, and the content of phosphoric acid in the catalyst is 0.1 to 20% by weight. The method of claim 1, wherein: The process according to claim 1, characterized in that the contact is carried out with an aqueous sulfuric acid solution and the content of sulfuric acid in the catalyst is 0.1 to 20% by weight.