JPS5862121A - Preparation of olefin - Google Patents

Abstract

PURPOSE:To prepare a lower olefin in high selectivity with a stable activity, by reacting methanol with dimethyl ether in the presence of a crystalline aluminosilicate zeolite catalyst obtained by using an inexpensive alcohol. CONSTITUTION:Methanol is reacted with dimethyl ether in the presence of a crystalline aluminosilicate zeolite obtained by keeping a mixture consisting of an alcohol, e.g. a 1-8C alcohol such as n-propyl alcohol or n-butyl alcohol, and the respective supply sources, e.g. silica, alumina and an alkali metal, and water at such a temperature and pressure as to modify the crystalline aluminosilicate zeolite as a catalyst to prepare a lower olefin. The molar ratio between the silica and the alumina in the catalyst is 10-500, preferably 20-300. Preferably, the alkali metallic ions in the zeolite are wholly or partially converted into protons.

Description

Detailed Description of the Invention The present invention uses crystalline aluminosilicate zeolite, which has a three-dimensional network structure in which silica and alumina share oxygen, as a catalyst, and reacts methanol and/or Id dimethyl ether to produce lower olefins. It relates to a manufacturing method.

Crystalline aluminosilicate zeolites exist in abundance in nature and can also be obtained synthetically, and have a certain crystal structure, with holes and tunnels the size of Cedar in the structure, which allow molecules of a certain size to be adsorbed. It has the function of excluding anything larger than that, and is also called a molecular sieve. The pores caused by voids and tunnels are determined by the form in which silica and alumina bond by sharing acid formations in the crystal structure. The electronegativity of the aluminum-containing tetrahedra is usually kept electroneutral by alkali metal ions, especially sodium and/or potassium.

Usually, in order to produce crystalline aluminosilicate zeolite, a method is used in which silica, alumina, alkali metal sources and water are mixed in desired proportions, and the mixture is hydrothermally treated under normal pressure or increased pressure.

There is also a method of using organic nitrogen compounds or organic phosphorus compounds as bases, and various zeolites with various adsorption capacities and catalytic actions are synthesized using this method, and the synthesis of these types of zeolites has become very popular in recent years. In particular, ZSM zeolite manufactured by Mopil Oil is synthesized using tetraalkylammonium compounds, tetraalkylphosphonium compounds, pyrrolidine, ethylenediamine, choline, etc., and its unique adsorption ability and catalytic action are attracting attention. Among them, ZSM-5 has a medium pore size of 5 to 6, so it can adsorb linear hydrocarbons and slightly branched hydrocarbons, but it cannot adsorb highly branched hydrocarbons. It is effective as a catalyst for catalytic deoxidization, decomposition, dioxication, alkylation, and polymerization, especially for the production of gasoline from methanol. This ZSM-5 is usually synthesized by hydrothermally treating a mixture consisting of silica, alumina, alkali metal sources, water, and a tetra-n-pro, pylammonium compound.

In recent years, much research has been conducted to obtain hydrocarbons by reacting methanol and/or dimethyl ether. The catalyst used in this reaction is generally what is called a solid acid, and many patents have been filed regarding various zeolites, heteropolyacids, etc. In particular, the aforementioned ZSM-5 zeolite manufactured by Mopil Oil is excellent for synthesizing hydrocarbons, mainly gasoline fractions, with up to 10 carbon atoms, using methanol as a raw material, and its life as a catalyst is relatively long and inexpensive. However, unfortunately, it is not suitable for producing lower olefins such as ethylene and propylene. In addition, ZSM-34 zeolite has high selectivity to ethylene and propylene as a catalyst for producing lower olefins in the same reaction, but its activity decreases extremely quickly and is not practical.

As a result of intensive research into the development of a zeolite catalyst that selectively produces lower olefins such as ethylene and propylene using methanol and/or dimethyl ether as a raw material and has stable activity, the inventors have discovered that expensive organic nitrogen compounds or without using organic phosphorus compounds,
We have discovered that the above objectives can be achieved by producing highly purified crystalline aluminosilicate zeolite by using alcohol, which is produced industrially on a large scale and at low cost, and by using this zeolite as a catalyst. , achieved the present invention.

Next, a method for producing zeolite according to the present invention will be described.

As the silica source, water glass, silica sol, silica gel, and silica can be used, and water glass and silica sol are preferably used. As an alumina source, sodium aluminate, aluminum sulfate, alumina sol, alumina, etc. can be used, but sodium aluminate and aluminum sulfate are preferred.

As the alkali metal source, for example, sodium oxide, sodium aluminate, sodium hydroxide, potassium hydroxide, etc. in water glass are used. Alcohol has 1 carbon number
~8 straight chain n-alcohols are preferred, with n-propyl alcohol and n-butyl alcohol being particularly preferred.

The composition of the reaction mixture to be subjected to hydrothermal treatment is preferably prepared in the following proportions.

5102/A1203 (hair management: 1 to 400, more preferably 2) 4000Hn'S10□0M So D:oo sea 1.0, more preferably 0.1-0.75H2010
H'''''C mowing: 10 to 300, more preferably 3
0-250ROH/8102□□□Hess = 0.1-5, more preferably 0.5-4 In order to obtain a mixture having a composition within this range, an acid such as hydrochloric acid, sulfuric acid, nitric acid, or alkali metal water may be added as appropriate. Add oxide.

This mixture is heated to 120-220°C, preferably 150-1
Heat and stir in a closed container at 90° C. for about 1 to 200 hours, preferably 5 to 50 hours. The reaction product is separated by sifting or centrifuging, washed with water to remove excess ionic substances, and then dried to obtain a white powder of crystalline aluminosilicate zeolite.

Table 1 shows the X-ray diffraction pattern of the dicate zeolite in the crystalline aluminosilicate IJ described in Example 1, where the SiO/Al2O3 molar ratio at the time of raw material preparation was 98 and n-butyl alcohol was used as the alcohol. .

Table 2 shows the X-ray pattern of this sample converted into hydrogen form by treatment with an aqueous ammonium chloride solution. These diffraction data are based on standard X-ray diffraction data obtained by alpha irradiation of copper
Since the peak height was obtained by the line technique, the peak height +■ is recorded on the recorder as a function of twice the Black angle θ, 2θ. ■N is the relative intensity, and 2 indicates the strongest peak.
This is a relative value when θ-23,05 is set to 100. These X-ray diffraction peaks are the highest peak 2θ = 23.14 of ZSM-54 zeolite, which is specified in Japanese Patent Publication No. 10064/1982, and 2θ = 23.05 of this crystalline aluminosilicate zeolite. It exists in 23.25 and is clearly distinguished. Also, low angle 2θ = 7.90
When comparing the peak intensities of ~7.95 and 8.85 to 8.90, the former peak is stronger in ZSM-5, whereas
The opposite is true for this crystalline aluminosilicate zeolite. The same thing can be said about the peak intensity at 2θ-23.5 to 24.0.

That is, in ZSM-5, the peak at 2θ=23.6 is
23.77 shoulders, whereas the one obtained here is clearly divided into two parts and has a low angle of 20=23.
The peak of 65-23.75 is 23.85-23, .
It's thicker than the 90's. This tendency is true for both the product immediately after synthesis and the product converted to a water accumulation type. However, in many other respects it is similar to the ZSM-5 pattern. Additionally, in general, ZSM-5 has a low-angle
In the latter case, the two peaks at −7.9 to 8.9 tend to become sharper, but this is hardly observed in this crystalline anovenosilicate zeolite.

Table-1 X-ray diffraction of crystalline anobenosiligate 8.90
9.94 64 245o 3.63
129.10 9.72 10 24.7
0 3.60 413.20 6.71
3 25.45 3.5Q 413.90
6.37 5 25.85 3.45
914.80 6.00 13 26.2
0 3.40 515.50 5.72
If 26.50 3.36 915.9
0 5.57. 7 26,85 3.3
2 1317.65. 5.02 7
27.35 3.26 417.80 4.9
8 15 29.15 3.06 1019
．． 20 4.62 4 29.30 3.0
5 1020.35 4.36 5 2
9.85 2.99 1520.85 4.2
6 12 30.20 2.96 922.
15 4. Old 7 32.702.74 52
3.05 3.86 100' 34,25
2.62 423.25 3.83 90
35.60 2.52 423.75 3
．． 75 48 36.00 2.49 52
3.90 3.72 36 Table-2 Crystalline aluminosilicate (H type) d, X-ray diffraction 7.90 11
．． 19 37 23.65 3.76 43
8.85 9.99 53 23.85
3.73 389.05 9.77 9
24.35 3.66 1913.15 6.7
3 3 24.70 3.60 313.
90 6.37 7 25.50 3.49
414.75 6.01 13 25.
85 3.45 915.50 5.72
12 26.15 3.44 515.85
5.59 7 26.50 3.36
817.60 5.04 6 26.80
3.33 1117.80 4,98
10 27.40 3.25 419.20
4.62 4 29.20 3.06 1
120.30 4.37 5 29.85
2.99 1420.80 4.27 1
2 32.70 2.74 522.10 4
,02 7 34.30 2.61 52
3.05 3,86. 100 35.60 2
．． 52 423.25 3.83 85
36.00 2.49 5 The specific surface area of the crystalline aluminosilicate zeolite obtained here is ZSM-5 (
Low specific surface area (190-280 m", /, !i') compared to 300-360 m"/, ji')
is also a characteristic.

Regarding adsorption properties, the crystalline aluminosilicate zeolite obtained here) l! It adsorbs n-hexane best, and also 3-methylpentane, which has one methyl group, but hardly adsorbs 2,2-dimethylbutane, which has two methyl groups, and has unique shape selectivity. . Therefore, this zeolite is considered to be a zeolite having a pore size intermediate between small pore size zeolites such as erionite and offretite and faujasite type X and Y type zeolites.

The crystalline aluminosilicate zeolite obtained here has excellent thermal stability, and its structure does not change much even after heat treatment at 900°C. This is convenient for pretreatment and regeneration in various practical reactions.

By using the crystalline aluminosilicate zeolite obtained here as a catalyst, lower olefins such as ethylene and propylene can be produced from methanol and/or dimethyl ether with high selectivity and stable activity.

The crystalline aluminosilicate zeolite used as a catalyst in the present invention is preferably a hydrogen type obtained by converting the alkali metal ions as cations after synthesis into protons in whole or in part by an ion exchange method. This exchange can be carried out using known ion exchange techniques by treating with an aqueous ammonium solution, such as an aqueous ammonium chloride solution, to exchange alkali metal ions with ammonium ions, followed by calcination to drive out ammonia and convert it into protons. It is also possible to convert it into protons by direct treatment with an aqueous hydrogen chloride solution. After treatment with an aqueous ammonium solution or an aqueous hydrogen chloride solution, the product can be thoroughly washed with water, dried, and calcined to serve as a catalyst for methanol and/or dimethyl ether conversion reactions. This firing is performed at a temperature of, for example, 300 to 700°C for 1 to 10 minutes.
This is achieved by treating for 0 hours.

The conversion reaction of methanol and/or dimethyl ether is
Any reaction method may be used as long as these raw materials are supplied as a gas and can be brought into sufficient contact with the solid catalyst, including a solid unreacted method, a flow U reaction method, a moving bed reaction method, and the like.

The reaction can be carried out under a wide range of conditions.

For example, reaction temperature 250-450'C1 weight time space velocity g
o, 1~20 hr-! Preferably 1 to 10 hr-
It can be carried out under conditions of a total pressure of 0.1 to 100 atm, preferably 0.5 to 10 atm. The raw material can also be diluted with water vapor or an inert gas such as nitrogen, alcohol, etc. and then supplied onto the catalyst. In the process of the present invention, the product stream consists of steam, hydrocarbons, and unreacted feedstock, the hydrocarbons being enriched in lower olefin inkers such as ethylene and propylene. The steam and hydrocarbon products are separated and purified from each other by known methods.

Next, the present invention will be specifically explained with examples.The present invention is not limited to these unless it exceeds the gist thereof.

Example 1 1.62 g of aluminum sulfate 16-18 permanent product was added to 86 g of water.
, p(/m) to make liquid A and No. 4 water glass (810□
24%, Na206.5%) 61.1 g to water 64%
This was used as Solution B. A while stirring vigorously.
Add solution B to the solution, then add 2.5N sulfuric acid aqueous solution 2
Then, 162 g of n-butyl alcohol was added thereto, and stirring was continued for about 10 minutes after the addition was completed to obtain an aqueous gel mixture. The 81027Alρ3 molar ratio of the preparation is 9
It was 8. The aqueous gel mixture was charged into an autoclave with an internal volume of 300 ml, and stirred at 180° C. for 16 hours under autoclaved pressure (500 r, p.

m,) was subjected to hydrothermal treatment. The reaction mixture was separated into a solid component and a solution part using a centrifuge, and the solid component was thoroughly washed with water and further dried at 100°C. The yield of the obtained product was 14.5p, and when it was analyzed by X-ray diffraction, it showed the pattern shown in Table 1, and observation with a scanning electron microscope showed that no other zeolite or gel coexisted. It was confirmed. The crystal size was 1-3μ.

The crystalline aluminosilicate zeolite obtained here was treated in air at 500°C for 16 hours. BET this thing
When the specific surface area was measured based on the method, it was 263.9 m
”/y.

Second, for 1 g of this calcined crystalline aluminosilicate zeolite, 5 m7 of 5% ammonium chloride aqueous solution! The procedure of mixing the two at a ratio of 1 and stirring at room temperature for 1 hour was repeated a total of 4 times to convert sodium ions to ammonium ions. After that, after washing thoroughly with water at room temperature,
It was dried at ℃ and then calcined in air at 500℃ for 16 hours to convert it into a hydrogen type. The X-ray diffraction pattern of this product is shown in Table 2.

The amount of ammonia adsorbed on this crystalline aluminosilicate zeolite in the hydrogen form was measured using a quartz spring balance. First, the sample was evacuated at 450°C for 2 hours to completely remove adsorbed substances, and then placed in an ammonia atmosphere of 15 torr at 100°C for 1 hour.
The sample was evacuated at 00° C. for 1 hour to remove the physically adsorbed ammonia, and then the sample temperature was raised at a rate of 10° C./min, and the amount of ammonia adsorbed at each temperature was observed. The results are shown in Table-3.

The crystalline aluminosilicate zeolite powder in the hydrogen form was compressed into tablets at a pressure of 400 kg/crI12, and then pulverized to a size of 10 to 20 mesh, 2 ml of which was filled into a reaction tube with an inner diameter of 10 mm. Liquid methanol was sent at a rate of 2 ml/hr to the vaporizer where 10
The mixture was mixed with argon gas fed at a rate of m1/min and sent to a reaction tube, where a reaction was carried out at 300°C. Analysis of the product was performed using a gas chromatograph.

The results are shown in Table 4.

Square 1 Carbon paste yield i so 2 for supplied methanol
Dimethyl ether is considered as an unreacted raw material, carbon-based selectivity for all other products Example 2 n-butyl alcohol to 16 g of n-propyl alcohol
Everything was carried out in the same manner as in Example 1 except that The yield of crystalline aluminosilicate zeolite obtained by hydrothermal treatment, washing with water, and drying was 14 g. The X-ray diffraction patterns of the dried product immediately after synthesis and the product converted into the hydrogen form were almost identical to those shown in Tables 1 and 2, respectively.

The specific surface area based on the BET method was 269.1 m/y. Tables 5 and 6 show the results of the ammonia nitrogen absorption amount and methanol conversion reaction activity after conversion to hydrogen form, respectively.

Example 3゜H aluminum sulfate, 3.24 g of 16-18 aquarium was added to 1 part of water.
00I to obtain liquid A, and No. 4 water glass 61.19 was dissolved in water 70.9 to form liquid B.

While stirring vigorously, Solution B was added to Solution A, and 16.9 g of n-propyl alcohol was further added, and stirring was continued for about 10 minutes after the addition was completed to obtain an aqueous gel mixture. Preparation S10□/λl! The 203 molar ratio was 49. Will everything else be implemented? It was carried out in the same manner as in 11. The crystalline aluminosilicate zeolite obtained by hydrothermal treatment, washing with water, and drying had 14.5I. Tables 7 and 8 show the results of the adsorption amount of ammonia and methanol conversion reaction activity of the dried product immediately after synthesis and the arsenic form converted into hydrogen form, respectively.

Comparative Example 1 Z8M-5 zeolite was prepared according to Example 3 of British Patent No. 1,402,981 of Mopil Oil.

That is, in 866 I of water, 1.87 g of aluminum sulfur beak, 16-18 hydrate, 4.22,9 g of concentrated sulfuric acid, and 1 part of sodium chloride.
9. Ogf was dissolved to obtain liquid A. 634g of water and No. 3 water glass (810□29%, Na209°5ch) 50.69
was dissolved to obtain liquid B. After stirring, solution B was added dropwise to solution A, and after thorough stirring, a mixed solution of 3.41 g of IJ-n-propylamine and 2.93 g of n-propyl bromide was added to obtain an aqueous gel mixture. Ta.

The 5102/Al2O3 molar ratio of the charge was 82.

The aqueous gel mixture was charged into an autoclave with an internal volume of 300 m1, and stirred at 160°C for 16 hours under autoclaved pressure (50 m1).
0r, l), m-) hydrothermally treated. The reaction mixture was separated into a solid component and a solution part using a centrifuge, and the solid component was thoroughly washed with water and further dried at 100°C. The yield of the obtained product was 13I, and when analyzed by X-ray diffraction, it was found that
The pattern almost coincided with that described in No. 02,981. All operations other than the above were performed in the same manner as in Example 1. BET
The specific surface area based on the method was 342 m/g. The results are shown in the adsorption amount of ammonia and methanol after conversion to hydrogen form.

Although the charged SiO□/Al2O3 molar ratio and ammonia adsorption amount during zeolite preparation are almost similar to those in Example 1.2, the methanol conversion reaction results show that both the yield and selectivity of ethylene and propylene are low. . This shows the superiority of olefin production according to the present invention.

Comparative Example 2゜Aluminum sulfate during preparation of ZSM-5 zeolite, 16
All procedures were carried out in the same manner as in Comparative Example 1, except that the amount of ~18 hydrate used was 0.94N. Preparation 810□/A
The 1203 molar ratio was 164. The yield of ZSM-5 zeolite obtained by hydrothermal treatment, washing with water, and drying was 12
．． It was 6II.

The specific surface area based on the BET method was 313.9 ml g. Tables 11 and 12 show the results of the ammonia adsorption amount and methanol conversion reaction activity after conversion to hydrogen form, respectively.

Even though the SiO□/Al2O3 molar ratio at the time of charging was increased and the ammonia adsorption amount was lower than in Example 1.2 and Comparative Example 1, the methanol conversion reaction results were not oriented towards ethylene and propylene. .

Claims (2)

[Claims] (1) Using as a catalyst a crystalline aluminosilicate zeolite obtained by holding a mixture consisting of silica, alumina, alkali metal sources, water and alcohol at a temperature and pressure that produce crystalline aluminosilicate zeolite, methanol and/or a method for producing lower olefins by reacting dimethyl ether. (2) The method according to claim 1, wherein the molar ratio of silica to alumina in the crystalline aluminosilicate zeolite is within the range of 10 to 500. (31 Crystalline aluminosilicate zeolite (4)
A method according to any of the patents, characterized in that the alcohol is an alcohol having 1 to 8 carbon atoms. , f5) The method according to claim 4, characterized in that the 7-alcohol alcohol is n-butyl alcohol. The method according to any one of the claims .