JPH0339970B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel modified crystalline zeolite and a method for producing hydrocarbons from lower alcohols or ethers thereof using the same. The production reaction of hydrocarbons from alcohol has been studied for a long time, and it is known that zeolite, polyphosphoric acid, zinc chloride, etc. are effective as catalysts. Among them, synthetic zeolites called ZSM-5 and ZSM-34 are attracting attention because of their high selectivity to lower olefins such as ethylene and propylene (Japanese Patent Application Laid-open No. 58499/1983). However, the activity of these catalysts deteriorates extremely quickly and is considered to be a problem from an industrial perspective. The present inventors have highly selected lower olefins such as ethylene and propylene from methanol catalyzed by modified crystalline zeolite obtained by ion-exchanging crystalline aluminosilicate belonging to the monoclinic system with Group A and Group B metals. The present invention was achieved by discovering that the deterioration of the catalyst activity was very small and the deterioration of the catalyst activity was very low. That is, the present invention expresses the molar ratio of oxides as 0.8-1.5M _2/o O・Al ₂ O ₃・10 −100SiO ₂・ZH ₂ O (where M is at least one metal cation, n is the valence of the metal cation and Z
is 0-40. ) A crystalline aluminosilicate belonging to the monoclinic system having a chemical composition of This invention relates to a substituted modified zeolite and a method for producing hydrocarbons using the same. The crystalline aluminosilicate belonging to the monoclinic system (hereinafter referred to as TSZ) used in the present invention is
It is a crystalline aluminosilicate disclosed in No. 143396. That is, the molar ratio of the oxide is 0.8−1.5M _2/o O・Al ₂ O ₃・10 −100SiO ₂・ZH ₂ O (where M is the metal cation and n is the valence of the metal cation. a crystalline aluminosilicate having a chemical composition of . First surface lattice spacing d (Å) Relative intensity (I/
I ₀ ) 11.2±0.2 S. 10.1±0.2 S. 7.5±0.15 W. 6.03±0.1 M. 3.86±0.05 VS 3.82±0.05 S. 3.76±0.05 S. 3.72±0.05 S. 3.64±0.05 S. As above An aluminosilicate having a crystal structure characterized by an X-ray diffraction pattern is hitherto unknown. These values are the results measured by conventional methods.
The radiation was a copper K-α doublet, and a scintillation counter equipped with a strip chart pen recorder was used to measure the peak height and its position as a function of 2Θ (Θ is the Black angle) from the chart. The relative intensities and lattice spacings (d) Å corresponding to the lines read and then recorded are measured. 1st
In terms of relative strength in the table, VS is the strongest, S. is strong, and M.
indicates medium-strong, W indicates weak. In Table 1, 2Θ=
The diffraction line at 14.7° (d=6.03Å) is a singlet.
and 2Θ=23° (d=3.86Å) and
The fact that the two diffraction lines at 2Θ = 23.3° (d = 3.82 Å) are clearly separated distinguishes it from the crystal structure of crystalline zeolite that has been previously proposed. In addition to the conventional method, powder X-ray diffraction analysis was performed to measure 2Θ (Θ is Black angle) with particularly high precision, and analysis of the results revealed that TSZ belongs to the monoclinic crystallographic system. found. for example
TSZ with a composition of 1.02Na ₂ O・Al ₂ O ₃・26.2SiO ₂・12.2H ₂ O has a=20.159 (±0.004) Å, b=
19.982 (±0.006) Å, c = 13.405 (±0.05) Å, α
=90.51° (±0.03°) indicates the monoclinic lattice constant.
The measured and calculated values of the lattice spacing of this representative TSZ and the Miller index are listed in Table 2. [Table] 〓
2.998 2.996 433
Such a specific X-ray diffraction pattern is caused by changes in the substituted cations of the synthetic aluminosilicate, such as changes to the hydrogen ion type, changes in the SiO ₂ /Al ₂ O ₃ ratio, etc., and the lattice spacing is significantly affected. I don't receive it. The preferred composition of TSZ in the as-synthesized form is 0.8−1.3M _2/o O・Al ₂ O ₃・25 −80SiO ₂・O−40H ₂ O (where M is the metal at least one type of cation, where n is the valence of the metal cation). The method for producing TSZ used in the present invention includes a silica source, an alumina source, an alkali source, and water, which consists essentially of an inorganic reactive material, and has the following composition SiO ₂ /Al expressed by the following molar ratio. ₂ O ₃ 10−130 M _2/o O _/ SiO ₂ 0.03−0.5 H ₂ O/M 2 ^/ o _O 100−1000 (where n is the valence of the metal cation and X ^- is the anion of the salt of the mineralizer) and autogenous pressure by maintaining the temperature in the range of about 120 to 230°C for about 10 to 20 hours. The preferred composition of the aqueous reaction mixture, expressed in molar ratios, is as follows. SiO ₂ ／Al ₂ O ₃ 20−120 Na ₂ O／SiO ₂ 0.03−0.3 (Na ₂ O＋M _2/o O)／SiO ₂ 0.03−0.3 H ₂ O／(Na ₂ O＋M _2/o O) 150−800 X ⁻ /SiO ₂ 0.05−15 Further, the optimum composition of the aqueous reaction mixture, expressed in molar ratio, is as follows. SiO ₂ ／Al ₂ O ₃ 30−115 Na ₂ O／SiO ₂ 0.05−0.3 (Na ₂ O＋M _2/o O)／SiO ₂ 0.05−0.3 H ₂ O／(Na ₂ O＋M _2/o O) 200−700 X ^- /SiO ₂ 0.1−10 In the above explanation, M is a metal cation selected from groups and groups of the Periodic Table of the Elements, in particular lithium, barium, calcium and strontium, and n is the metal cation. It is the valence of the ion. M _2/o O and Na ₂ O actually used here
are free M _2/o O and Na ₂ O, generally in the form of very weak acid salts such as aluminates, silicates, which are effective in hydroxide and zeolite synthesis. Moreover, the above-mentioned free Na ₂ O can be adjusted by adding aluminum sulfate, sulfuric acid, nitric acid, etc. In preparing the aqueous reaction mixture, the source of the oxidic reactant of the composition used is one commonly used in the production of synthetic zeolites. For example, silica sources include sodium silicate, silica gel, silicic acid,
These include aqueous colloidal silica gel, dissolved silica, powdered silica, and amorphous silica. As the alumina source, activated alumina, γ-alumina, alumina trihydrate, sodium aluminate, and various aluminum salts such as aluminum chlorides, nitrates, and sulfates can be used. The metal oxide represented by M _2/o O is added to the reaction mixture in the form of a water-soluble salt or in the form of a hydroxide. Na ₂ O as a source of sodium cations is added in the form of sodium hydroxide, sodium aluminate or sodium silicate, and Li ₂ O as a source of lithium cations can be added as hydroxides, halides, sulfates and chlorates. It is added in the form of An aqueous reaction mixture is prepared by mixing the silica source, alumina source, alkaline source and water. Particularly suitable silica sources are sodium silicate, water glass, colloidal silica, etc., and alumina sources are sodium aluminate, aluminum sulfate, etc. The water content of the aqueous reaction mixture is important, and setting the water content within the above range also facilitates mixing and stirring of the gel of the reaction reagents. By adding a mineralizing agent to the aqueous reaction mixture during crystallization, the crystallinity of the crystallized product can be further improved, and the formation of amorphous aluminosilicate can be suppressed. NaCl as a mineralizer,
Na ₂ CO ₃ , Na ₂ SO ₄ , Na ₂ SeO ₄ , KCl, KBr,
Neutral salts of alkali metals or alkaline earth metals such as KF, BaCl ₂ or BaBr ₂ can be used. A preferred mineralizing agent is NaCl. The produced crystalline aluminosilicate is separated from the solution by filtration, then washed with water and dried. The modified TSZ used in the present invention can be obtained by replacing at least a portion of the cations in the TSZ obtained above by heat treatment and/or ion exchange. Cation exchange can be carried out by contacting the crystallized product with the desired exchange cation or salt of cations. In this case, neutral salts of desired cationic metals can be used, and chlorides, nitrates, sulfates, acetates, etc. are particularly preferred. In the present invention, preferred substituent ions of ion-exchange modified TSZ for α producing hydrocarbons from lower alcohols or ethers thereof are at least one metal selected from Group A and Group B metals of the Periodic Table of the Elements.
Seeds are preferred, especially magnesium, calcium,
Strontium, barium and lanthanum are preferred. Ion exchange is a hydrogen ion exchange type obtained by acid treatment or substitution with NH ₄ ⁺ and heat treatment.
It can also be obtained by cation exchange of TSZ. This ion-exchanged modified TSZ is SiO ₂ /Al ₂ O ₃
In the molar ratio range of 25-80, TSZ before modification
There is virtually no change in the crystal structure. The raw materials applied to the hydrocarbon production method according to the present invention are alcohols having 4 or less carbon atoms and their ethers. i.e. methanol, ethanol, n-propanol, i-propanol, n-
Butanol, s-butanol, t-butanol,
Alternatively, mixtures of these can be used. Similarly,
Dimethyl ether and the like derived from these alcohols also serve as raw materials. Particularly preferred raw materials are methanol, dimethyl ether and mixtures thereof. In the present invention, the method of reacting methanol with a modified TSZ catalyst is carried out by continuously supplying methanol to the reaction system and bringing it into contact with modified TSZ in the gas phase using a fluidized bed or a fixed bed. It is preferable to supply methanol to the reaction system after gasifying it in advance using an evaporator, preheating, etc. Gases that are inert to the reaction, such as nitrogen, steam, or argon, may also be supplied to the reaction system together with the raw materials as a carrier gas or diluent gas. can. The catalytic reaction is carried out at a reaction pressure of 0.1-50 atm, preferably 0.-20 atm, at 275-550°C, preferably at 300-550°C.
Under reaction temperature conditions of 500°C and methanol weight hourly space velocity of 0.1-10 W/H/W, preferably 1-5
This is done by keeping it within the range of . The above-mentioned reaction pressure is not a factor having a particularly significant influence on the reaction result, and is appropriately selected from the viewpoint of economic efficiency. If the reaction temperature is too low or the weight hourly space velocity is too high, the conversion rate of methanol to hydrocarbons will be low, and if the reaction temperature is too low, productivity will decrease. Furthermore, if the reaction temperature is too high, by-products such as methane will increase, leading to a decrease in the yield of lower olefins. In the present invention, almost no by-products of hydrogen, carbon monoxide, and carbon dioxide are observed, and the reaction products are mainly hydrocarbons consisting of olefins having 2 to 6 carbon atoms, small amounts of paraffins, and aromatics, and water. Each fraction of hydrocarbons can be easily separated and obtained by known methods. EXAMPLES The present invention will be explained in more detail with reference to Examples below, but the present invention is not limited thereto. Example 1 Production of TSZ 2.5g of aluminum sulfate was dissolved in 70g of pure water, and 5.4g of concentrated sulfuric acid (95wt.%) was added thereto.
An aluminum sulfate solution (liquid A) was prepared. next
25g of pure water and 63g of water glass (Na ₂ O; 9.5wt.%,
A mixed solution (liquid B) with SiO ₂ (28.6 wt.%) was prepared. Solution A and solution B were simultaneously added to a sodium sulfate aqueous solution in which 6 g of sodium sulfate was dissolved in 100 g of pure water with stirring, and the result was 8.8Na ₂ O・Al ₂ O ₃・80SiO ₂ expressed as an oxide leakage ratio. An aqueous reaction mixture with the composition 3458H ₂ O was obtained. In this case, the concentration of sodium sulfate, which is the mineralizing agent, is 0.28 relative to SiO ₂
It was mole. The aqueous reaction mixture was poured into a SUS autoclave and heated to 170°C under autogenous pressure.
It was kept at ℃ for 20 hours to crystallize and obtain a solid product (TSZ). The obtained solid product was separated, washed with water, and then dried at 110°C. A sample of this solid product was subjected to chemical analysis and revealed that Na ₂ O;
2.15wt.%, Al ₂ O ₃ ; 3.16wt.%, SiO ₂ ; 88.8wt.%,
A chemical composition of H ₂ O; 5.9 wt.% was obtained. When this was expressed as the molar ratio of oxides, it was as follows. _{1.12Na2O.Al2O3.47.8SiO2.10.6H2O} When _this product was _subjected to X-ray analysis, _the results shown in Table ₃ were obtained. This X-ray analysis was carried out by the conventional method of powder X-ray diffraction. The irradiation radiation is a copper K-α doublet, and the X-ray tube voltage and tube current are respectively
The voltage was 40KV and 70mA. A scintillation counter equipped with a goniometer and a strip chart pen recorder was used to measure the diffraction angle 2Θ and the intensity of the diffraction lines. At this time, the scanning speed is 2Θ
The rotation rate was 2°/min, and the rate meter time constant was 1 second. Table 3 Lattice spacing d (Å) Relative intensity I/I ₀ (%) 11.17 51 10.07 47 9.96 9.75 21 9.01 2 7.44 4 7.09 2 6.72 6 6.37 9 6.01 13 5.71 10 5.58 11 5.38 3 5.15 2 5.04 6 4.99 7 4.62 5 4.37 10 4.27 11 4.09 4 4.02 6 3.86 100 3.82 68 3.76 45 3.73 46 3.65 29 3.60 5 3.49 7 3.45 10 3.36 4 3.31 11 3.26 5 3 .05 14 3.00 13 2.97 14 2.94 6 Production of hydrogen type TSZ 20g of TSZ catalyst at 90℃
Contact with 1N ammonium chloride aqueous solution of 100c.c. for 4 times for ion exchange, and further 500c.c.
After washing with ml of pure water, it was dried at 120°C for a day and night, and then calcined in air at 500°C for 3 hours to obtain hydrogen type zeolite (H-TSZ). Example 2 Production of Mg-modified zeolite 2 g of TSZ obtained in Example 1 was added to 30 ml of 1N Mg
(NO ₃ ) 90 ion exchange by immersing in ₂・6H ₂ O aqueous solution.
℃ for 24 hours. After over-cleaning, it was dried at 120℃ for a day and night, and then baked in the air for 3 hours to produce Mg-modified TSZ.
(Mg/Na-TSZ) was obtained. This Mg/Na-TSZ
contained 0.50 wt.% magnesium. Example 3 Production of Mg-modified zeolite 2 g of hydrogen type zeolite obtained in Example 1 was added to 30 ml of
Ion exchange was performed at 90°C for 24 hours by immersing it in a 1N Mg(NO ₃ ) ₂ ·6H ₂ O aqueous solution. After over-cleaning, 120
Mg
Modified TSZ (Mg/H-TSZ) was obtained. This Mg/H
-TSZ contained 0.56 wt.% magnesium. Example 4 Production of Mg-modified zeolite In the same manner as in Example 3, except that Mg(CH ₃ COO) ₂ ·4H ₂ O was used instead of Mg(NO ₃ ) ₂ ·6H ₂ O. Mg-modified TSZ (Mg/H-TSZ)
was manufactured. This Mg/H-TSZ contained 0.85 wt.% magnesium. _Example 5 Production _of Ba _{-modified zeolite Ba- modified TSZ} (Ba /H-TSZ) was produced.
This Ba/H-TSZ contained 3.2 wt.% barium. _Example 6 Production _of La-modified zeolite _{La -} modified TSZ ( _La / H-TSZ) was produced. This La/H-TSZ contained 0.3 wt.% lanthanum. _{Example 7 Production of} Ca-modified zeolite Ca _- modified TSZ ( Ca/H-TSZ) was produced. This Ca/H-TSZ contained 0.85 wt.% calcium. Example 8 Production of Sr-modified zeolite Same procedure as in Example 3 except that Sr(CH ₃ COO) ₂ ·1/2H ₂ O was used instead of Mg(NO ₃ ) ₂ ·6H ₂ O. Method of Sr-modified TSZ (Sr/H-TSZ)
was manufactured. This Sr/H-TSZ contained 1.58 wt.% strontium. Examples 9 to 15 0.35 g (approximately 1.0 cc) of the modified TSZ zeolite produced in Examples 2 to 8 was packed into a glass reactor, and the catalyst bed was heated at 500°C for 2 hours in a nitrogen stream.
The mixture was maintained for a certain period of time, and then the temperature was lowered to the reaction temperature under a nitrogen stream. The temperature of the reactor was maintained at the reaction temperature. Next, nitrogen was introduced as a carrier gas into a saturator in which the partial pressure of methanol was maintained at 0.163 atm, and methanol was passed through the catalyst bed at a weight hourly space velocity of 2.3 W/H/W. The decomposition products 0.3 to 0.5 hours after the start of the reaction were analyzed by gas chromatography, and the results shown in Table 4 were obtained. Comparative Examples 1 to 4 Example 9 using H-TSZ manufactured in Example 1
Hydrocarbons were produced from methanol in a similar manner. The results are shown in Table 4. [Table] [Table] Examples 16-17, Comparative Examples 3-4 Mg/H-TSZ obtained in Examples 4, 6 and 1,
Using La/H-TSZ, H-TSZ, and ZSM-34 manufactured by JP-A-55-58499, the reaction temperature was 300°C, and the methanol weight space velocity was 2.4W/H/
A methanol conversion reaction was carried out in the same manner as in Example 9 except that W was used. The decomposition products were analyzed 0.4 hours and 8 hours after the start of the reaction, and the results are shown in Table 5. Table 5 proves that the modified TSZ zeolite is a catalyst with little deterioration over time. 【table】

Claims (1)

[Claims] 1 0.8-1.5M _2/o O・Al ₂ O ₃・10 −100SiO ₂・ZH ₂ O expressed in molar ratio of oxides (where M is at least one metal cation , n is the valence of the metal cation, and Z
is 0-40. ) A crystalline aluminosilicate belonging to the monoclinic system having a chemical composition of A modified zeolite in which at least a part of M in the above compositional formula is replaced. Lattice spacing d (Å) Relative intensity 11.2±0.2 S. 10.1±0.2 S. 7.5±0.15 W. 6.03±0.1 M. 3.86±0.05 VS 3.82±0.05 S. 3.76±0.05 S. 3.72±0.05 S. 3.64± 0.05 S. 2 In the production of hydrocarbons by contacting a lower alcohol or its ether with a zeolite catalyst, the zeolite has an oxide molar ratio of 0.8-1.5M _2/o O.Al ₂ O _3.10 -100SiO ₂ ZH ₂ O (where M is at least one metal cation, n is the valence of the metal cation, and Z is 0-40). , and having a powder X-ray diffraction pattern showing at least the lattice spacing shown below, a crystalline aluminosilicate belonging to the monoclinic system is ion-exchanged with a Group A or Group B metal compound to obtain M in the above compositional formula. A method for producing hydrocarbons, the method comprising using a modified zeolite in which at least a portion of the zeolite has been substituted. Lattice spacing d (Å) Relative intensity 11.2±0.2 S. 10.1±0.2 S. 7.5±0.15 W. 6.03±0.1 M. 3.86±0.05 VS 3.82±0.05 S. 3.76±0.05 S. 3.72±0.05 S. 3.64± 0.05 S.