JPH0193545A - Production of lower olefin - Google Patents

Abstract

PURPOSE:To obtain the titled compound readily and in high selectivity, by using a novel crystalline aluminosilicate zeolite containing an alkaline earth metal having stable activity as a catalyst and bringing methanol into contact with the catalyst under a specific reaction condition in a gas phase. CONSTITUTION:Methanol and/or dimethyl ether in a gas phase is brought into contact with an crystalline aluminosilicate zeolite catalyst containing an alkaline earth metal which has 5-6Angstrom pore diameter, a composition shown by the formula (M is alkali metal and/or H; M' is alkaline earth metal, preferably Ca; a=0-1.5; b=0.2-40; with the proviso that a+b>1; c=12-3,000: n:0-40), X-ray diffraction figure shown by the table and is produced by previously adding an alkaline earth metallic salt to a crystal producing raw material in the production of the crystal, at 0.1-20hr<-1> weight time space velocity at 300-600 deg.C under 0.1-100atm. total pressure to give the aimed compound, especially ethylene or propylene.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a method for producing lower olefins from methanol and l or dimethyl ether using a novel alkaline earth metal-containing crystalline aluminosilicate zeolite as a catalyst.

The alkaline earth metal-containing crystalline aluminosilicate zeolite (hereinafter sometimes simply referred to as zeolite or crystalline aluminosilicate) used in the present invention has a higher SiO□/An, 03 ratio than conventionally known zeolite catalysts, It also has a high content of alkaline earth metals, at least a part of which cannot be easily exchanged to other ions by ion exchange methods, and some of the raw materials for producing high aldo The key point is that an alkaline earth metal salt is pre-existing as a salt. In conventionally known crystalline aluminosilicates, a+b is 1 or less than 1, but the crystalline aluminosilicate of the present invention is characterized in that a+b is greater than 1.

The method for producing lower olefins of the present invention relates to a method for producing C1-04 lower olefins, which comprises contacting methanol and/or dimethyl ether with the above-mentioned zeolite catalyst under heating in the gas phase, and includes decomposition into CO and CO□. It produces lower olefins with high selectivity, produces less paraffin and aromatic by-products, suppresses carbon deposition on the catalyst, and does not cause a decrease in catalyst activity or deterioration of the catalyst even at high temperatures.

[Prior art]

In recent years, there has been concern about the supply of petroleum resources, especially as Japan's dependence on foreign sources exceeds 99%.
Effective utilization of natural gas and the like has become an important issue, and there is a need to establish an industrial synthesis method for organic compounds such as olefins, paraffins, and aromatics from methanol obtained from methane, CO, and the like.

Various types of crystalline aluminosilicate have been known, but among them, crystalline aluminosilicate zeolite is the most representative. It has a certain grain structure, and has many voids and tunnels within its structure, and has the function of adsorbing molecules up to a certain size, but excluding molecules larger than that, and is also called a single-molecular sieve. be done. Pores caused by voids and tunnels are determined by the form in which Sin, An, and O bond together by sharing oxygen in the crystal structure. The electronegativity of the aluminum-containing tetrahedra is usually kept electroneutral by alkali metal ions, especially sodium and/or potassium.

Normally, to produce crystalline aluminosilicate zeolite, various zeolites with adsorption ability and catalytic activity for Sin, An', o, and alkali metal ions are synthesized.
In recent years, the synthesis of this type of zeolite has become very popular. 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 people, so it can adsorb linear hydrocarbons and slightly branched hydrocarbons, but it cannot adsorb highly branched hydrocarbons. It has the characteristic that it does not. This ZSM-
5 is usually synthesized by hydrothermally treating a mixture consisting of Sin, AQ20:I, each source of alkali metal, water, and a tetra-n-propylammonium compound.

It is proposed to react with methanol and/or dimethyl ether. In particular, the aforementioned ZSM-5 made 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 stable. However, it is not suitable for producing lower olefins such as ethylene and propylene. Also, the same < ZSM
-34 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.

〔the purpose〕

The present invention aims to provide a catalyst that selectively produces hydrocarbons, particularly lower olefins such as ethylene and propylene, using methanol and/or dimethyl ether as a raw material, and has stable activity. Compositional formula aM, 0 ~ bM'0 ・i, o, ・csiO, ・n produced in the presence of similar metal salts
H,0 (alkali metal and/or hydrogen atom, H
' is an alkaline earth metal, a is 0 to 1.5. b is 0.2
~40. However, a+b>1. It has been found that a crystalline aluminosilicate having a specific X-ray diffraction pattern as described below is suitable for the purpose.

The above-mentioned alkaline earth metal-containing crystalline aluminosilicate zeolite has an X-ray diffraction pattern similar to that of a conventionally known zeolite catalyst having a pore size of 5 to 6 people. metal/
Both have high AΩ ratios, and are distinguished in terms of catalytic activity, making them novel substances. In addition, it is widely known that the method for producing aluminosilicate of the present invention involves modifying raw materials with earth metal ions during crystal production, and usually proton (H''') crystalline aluminosilicate is modified with alkaline earth metal ions. A method is used in which the particles are supported by ion exchange.

However, with this ion exchange method, it is difficult to support a large amount of alkaline earth metal ions, and it requires a lot of labor and is not economical.

For example, the limit is to introduce up to the theoretical amount of about 80.
Normally, it can only be introduced up to about 50%.

Surprisingly, however, the present inventors were able to very easily incorporate a desired amount of alkaline earth metal salt by adding an alkaline earth metal salt during the synthesis of crystalline aluminosilicate. According to the present invention, the conversion reaction of scales containing alkaline earth metal ions and methanol and/or dimethyl ether has been completed.

Conventionally, when producing crystalline aluminosilicate, the coexistence of alkaline earth metal salts in the production raw materials has been avoided because it disrupts the crystal lattice arrangement, prevents crystal growth, and tends to produce amorphous products.

However, according to the research of the present inventors, using a tetrapropylammonium compound as a crystallization regulator, Z
When producing SM-5 type crystalline aluminosilicate,
Higher SiO,/Afl, O than conventionally adopted
, it is possible to obtain crystalline aluminosilicate without any problems even if a large amount of alkaline earth metal salt is pre-existing in the raw material for producing aluminosilicate crystals, which results in an unexpectedly excellent catalyst. It was discovered that this substance shows activity.

Next, the crystalline silica sol containing an alkaline earth metal according to the present invention is preferably used.

Alumina sources include aluminum nitrate, aluminum sulfate,
aluminum, sodium aluminate, alumina, etc. can be used, and aluminum nitrate, aluminum sulfate, and sodium aluminate are preferred.

Examples of alkali metal ions used include sodium oxide, sodium aluminate, sodium hydroxide, potassium hydroxide, sodium chloride, and potassium chloride in water glass.

As the alkaline earth metal ion, organic salts such as acetate and propionate, and inorganic salts such as chloride and nitrate are used.

As the alkaline earth metal, calcium is particularly preferred, followed by magnesium, and strontium and barium tend to require high temperatures to develop their catalytic activity.

Mix together. That is, 5i02/AQzOa (
molar ratio) is 12 to 3000, more preferably 50 to 50
0; OH-/Sin, (Mo/L/ratio) is 0.02-1
0, more preferably 0.1-0.5;)1.0/SiO
.

(mole ratio) is 1 to 1000. More preferably 30-8
0; Tetrapropylammonium compound/SiO□ (mole ratio) is 0.02 to 2, more preferably 0.05 to 0.0;
5 and alkaline earth metal/AΩ (yX ratio) is 0.0
3 to 300, more preferably 0.5 to 8. In order to obtain a mixture having a composition within this range, the pH of the system is adjusted to an appropriate value of 11 or less by adding an acid such as hydrochloric acid, sulfuric acid, nitric acid, or an alkali metal hydroxide as necessary. .

This mixture is heated to 80-200°C, preferably 150-18°C.
Heating at 0"C for about 1 to 200 hours, preferably 5 to 50 hours under normal pressure or increased pressure, generally heating and stirring. The reaction product is separated by filtration or centrifugation, and excess ionic substances are removed by washing with water. After removing it, it is dried and fired.

For example, by ion-exchanging using an inorganic acid such as hydrochloric acid, sulfuric acid, or nitric acid, or an organic acid such as formic acid or acetic acid, or by ion-exchanging using an ammonium compound and then firing, the proton (Hl) is substituted. It can be converted to the hydrogen form of crystalline aluminosilicate. in this case,
Alkali metals are easily partially or entirely replaced by protons (Hl), but alkaline earth metals are only partially replaced by protons (Hl).

Conventionally known aluminosilicates modified with alkaline earth metals are hydrogen type or alkali metal type aluminosilicate into which alkaline earth metal ions are introduced by an ion exchange method, and in this case, the introduced alkaline earth metal The ions can be converted back into the hydrogen form etc. by an ion exchange method, and the crystalline aluminosilicate produced in this way can be distinguished from the aluminosilicate obtained in the present invention by aM20 `` bM'O '' as described above. AQ, O,” csio
It has a composition of 2" nH,0 (where a, b, c, M, M' are the same as above) and a pore size of 5 to 6 people, and the fired product has the following representative X A line diffraction image is shown.

Table 1: Before firing, the diffraction images of 3.85 and 3.82 people are integrated to give the strongest image.

This aluminosilicate adsorbs straight chain or slightly branched paraffins such as n-hexane and 3-methylpentane, but does not adsorb compounds having tertiary carbon atoms such as 2.2 to dimethylbutane.

In the present invention, in order to use the crystalline aluminosilicate as a catalyst for producing lower olefins from methanol and/or dimethyl ether, all or most of the alkali metal and a part of the alkaline earth metal are replaced with protons (H+). It is usually the hydrogen type.

This exchange can also be performed by converting into an aqueous solution of an ammonium compound, such as an ammonium chloride type, using known ion exchange techniques. After being treated with an ammonium aqueous solution or a hydrogen chloride aqueous solution, it is thoroughly washed with water, dried, and fired.

This firing is performed at a temperature of, for example, 300 to 700°C for 1 to 100°C.
This is achieved through time processing.

As mentioned above, some or all of the alkali metal ions are converted to protons (H+), but the alkaline earth metal ions remain within the crystal and have a very characteristic effect on its catalytic performance. This is different from the case where alkaline earth metal ions are supported by a known ion exchange method.

The aluminosilicates thus obtained can be used as catalysts as is, but can also be further modified by conventional ion exchange or impregnation operations. The metal to be modified may be a monovalent alkali metal, a divalent alkaline earth metal, lanthanum, alkali, or, if desired, may be mixed with a suitable carrier such as clay, kaolin, alumina, etc.

Next, a method for producing lower olefins from methanol and/or dimethyl ether using the catalyst of the present invention will be described.

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 a solid catalyst, such as a fixed bed reaction method, a fluidized bed reaction method, and a moving bed reaction method.

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

For example, the reaction temperature is 300-600℃, the weight-time space velocity is 0.
．． It can be carried out under conditions of 1-20 hr-', preferably 1-10 hr-1, and a total pressure of 0.1-100 atm, preferably 0.5-10 atm. The proportion of lower olefins such as ethylene and propylene in the hydrocarbon can be increased by setting the yK additive to water vapor or an inert gas, for example. For the production of ethylene, the lower temperature is preferable;
Preferably, elevated reaction temperatures are employed for the production of propylene; the steam and hydrocarbon products are separated from each other and purified by known methods.

〔effect〕

As shown in Figure 1, in proton-type crystalline aluminosilicate that does not support alkaline earth metal ions such as calcium, an almost complete decrease in activity is observed at 510°C (■). When calcium is supported on proton-type crystalline aluminosilicate by an ion exchange method, the yield of ethylene and propylene is improved, but the catalyst tends to deteriorate at temperatures above 540°C (■)
On the other hand, the synthesis reaction of olefin from methanol and/or dimethyl ether using the crystalline aluminosilicate according to the present invention is an exothermic reaction, and the temperature of the reaction system naturally rises, so the reaction is carried out at a high temperature. There is no particular problem in terms of energy consumption; rather, it is easier to control the temperature of the reaction system than keeping it at a low temperature, and the reaction rate increases, so there is an advantage that a small reactor can be used. However, due to the material of the reactor, such as stainless steel, there are problems with using high temperatures of 600°C or higher;
At high temperatures of 0°C or higher, there is a possibility that the catalyst crystals may collapse due to water vapor present in the reaction system, so the upper limit of the reaction temperature that can be practically adopted is limited to about 600°C.

In the olefin production reaction in which the catalyst of the present invention is used, methanol and dimethyl ether are both starting materials, so when calculating the selectivity, the selectivity to lower olefins is higher than that of other comparative catalysts, and paraffins and B
,T,X, are generated less.

The point is that there is no decrease in catalytic activity at high temperatures.

An aluminosilicate containing an alkaline earth metal in a higher amount than that specified in the present invention was prepared, and then a part of the alkaline earth metal was removed by an ion exchange method to obtain the alkaline earth metal content specified in the present invention. Catalysts reduced within this range have surprisingly low selectivity to olefins and CO
The decomposition into CO8 and CO8 is promoted, and a significant difference in catalyst performance is observed.

〔Example〕

Next, the present invention will be explained in detail using Examples and Comparative Examples, but the present invention is not limited thereto unless it exceeds the gist thereof.

Reference Example 1 A solution of 1.14 g of sodium hydroxide dissolved in 0.75 g of aluminum nitrate nonahydrate and 20 g of calcium acetate water is added. Furthermore, a solution of 8.11K of tetrapropylammonium bromide in 30 g of water was added, and stirring was continued for about 10 minutes to obtain an aqueous gel mixture. This charging molar ratio is 5iO1,/AΩ,O,=300.

This aqueous gel mixture was charged into an autoclave with an internal volume of 300~ and subjected to hydrothermal treatment at 160°C under self-pressure for 18 hours with stirring (500 r, p, m). 6 The reaction product was separated into solid components using a centrifuge. The solid components were separated into solution parts, thoroughly washed with water, and then dried at 120°C for 5 hours.
Next, it was treated in air at 520°C for 5 to 10 hours.

Next, 1 g of this calcined crystalline aluminosilicate was mixed with a 0.6N aqueous hydrogen chloride solution at a ratio of 15 to 1, followed by stirring at room temperature for 24 hours. Thereafter, it was thoroughly washed with water at room temperature, dried at 120°C, and then fired in air at 520°C for 5 hours to convert it into a hydrogen type.

Table 2 shows the charging ratio of the 0M material used to produce the earth metal-containing crystalline aluminosilicate zeolite, and the analysis results of the crystalline aluminosilicate obtained in Reference Examples 4 and 7 and those converted into hydrogen form are shown in Table 3A and 3A. Shown in Table B,
Moreover, the X-ray diffraction pattern of the product (fired product) obtained in Reference Example 4 is shown in FIG.

Note that this novel data was obtained using standard X-ray techniques by irradiating the copper with alpha radiation, and the peak height I is recorded on a recorder as a function of twice the Black angle θ, which is 20. . I/Io is a relative intensity, and is a relative value when 2θ=23.1° showing the strongest peak is set as 100.

Comparative Reference Examples 1 to 3 Three types of crystalline aluminosilicates were synthesized in the same manner as in Reference Example 1, except that no alkaline earth metal salt was added.

Comparative Reference Example 1 corresponds to Reference Examples 1 to 3, and the analysis results of the Comparative Reference Example are shown in Tables 2 and 3, respectively.

Comparative Reference Example 4 The charging molar ratio (Sin, /
After converting the crystalline aluminosilicate (Afl, O, = 300) into a hydrogen form, ion exchange with calcium ions was performed using a conventional method.

IN CaCl2. for 5 g of sample. 40m of solution for the first time
1 and stirred in an oil bath adjusted to 80°C equipped with a reflux condenser.

Remove the replacement solution by decantation every 3 hours,
Added 30 mQ of fresh exchange solution. After repeating this operation 20 times, the product was thoroughly washed with water and filtered until no CQ-ions were observed, dried, and then calcined at 500°C for 3 hours to obtain a calcium-supported product. The amount of calcium supported was 45% of the isoelectric amount.

Table 3A Analysis of Na-type crystalline aluminosilicate zeolite 1 Table 3B Analysis of H+Pear-shaped crystalline aluminosilicate zeolite 8*
Analysis was performed by atomic absorption spectrometry.

Examples 1 to 12, Comparative Examples 1 to 3 Reference Examples 1 to 9 and 11 to 13, Comparative Reference Examples 1.2 and 4
The crystalline aluminosilicate powder obtained in the hydrogen form was compressed into tablets at a pressure of 400 kg/cd, and then crushed into 10 to 20 meshes.
The OI reaction tube was filled. Liquid methanol 4+nQ/
hr (The reaction is a gas phase reaction, but if the raw material supply amount is expressed in liquid phase, it is sent to the vaporizer at a rate of LH5V = 2hr''1), where it is mixed with argon gas sent at 10mQ/win. 300-600
The 0 reaction was carried out at 300°C, and the temperature was increased by 20°C every 2 hours up to 600°C.

Further, the product was analyzed using a gas chromatograph.

A summary of the results is shown in Table 4, and further Example 2゜4.7,1
1. Details of the results obtained in Comparative Examples 1, 2 and 3 are shown in Table 5. Carbon base selectivity (%) for reaction temperature and added methanol (%) Table 6. Current flow example 4) Reaction temperature and added methanol Carbon base selectivity for reaction temperature and added methanol (%) Carbon base selectivity for reaction temperature and added methanol (%) Carbon base selectivity for reaction temperature and added methanol (Example 11) %) Table 9 (Comparative Example 1) Reaction temperature and carbon base selectivity for added methanol (phantom Table W (Comparative Example 2) Reaction temperature and carbon base selectivity for added methanol (1 Table 11 (Comparative example) 3) Reaction temperature and carbon base selectivity C% for added methanol) Example 2. The relationship between the total yield of ethylene and propylene obtained in Comparative Examples 1 and 3 and the reaction temperature is shown in Figure 1. In Figure 0, it is understood that the catalyst of the invention provides a high yield of ethylene/propylene and maintains high catalytic activity without deterioration even in a high temperature range.

line! indicates Example 2, line ■ indicates Comparative Example 1, and line m indicates Comparative Example 3.
The results are shown below.

Similarly, the relationship between the ethylene dipropylene yield and the reaction temperature obtained in Examples 4, 8.9 and Comparative Example 2 is also shown in FIG. Line V shows the results of Example 8, line ■ shows the results of Example 9, and line ■ shows the results of Comparative Example 2.0 As is clear from the figure, Example 4 contains Ca and shows excellent results, and Mg Example 8 containing ASR maintains its activity, while Example 9 containing ASR exhibits activity in a high temperature range.

[Brief explanation of the drawing]

Figure 1 shows the yield (%) on the vertical axis and the reaction temperature (%) on the horizontal axis.
Figure 2 is a graph showing the results of Example 2, Comparative Examples 1 and 3 by taking ``C'', and Figure 2 also shows the yield (%) on the vertical axis and the reaction temperature ('C) on the horizontal axis. This is a graph showing the results of Example 4.8.9 and Comparative Example 2, and FIG. 3 is an X! diffraction diagram of the product of Reference Example 4. I...Example 1, ■... Comparative Example 1.II [...Comparative Example 3, ■...Example 4, ■...Example 8.VI
...Example 9, ■...Comparative example 2

Claims (3)

[Claims] (1) Methanol and/or dimethyl ether in the gas phase, aM_2O・bM′O・Al_2O_3・cSiO_
2.nH_2O (where M is an alkali metal and/or hydrogen atom, M' is an alkaline earth metal, a is 0 to 1.5, b is 0.2 to 40, where a+b>1, c is 12 to 3000 and n is 0 to 40), has the X-ray diffraction pattern shown in Table 1, and is manufactured by allowing an alkaline earth metal salt to be present in the crystal manufacturing raw material during crystal manufacturing. Alkaline earth metal-containing crystalline aluminosilicate zeolite catalyst and weight hourly space velocity of 0.1 to 20 hr^-^1,3
A method for producing lower olefins comprising contacting at a reaction temperature of 00 to 600°C and a total pressure of 0.1 to 100 atm. (2) The method according to claim 1, wherein the alkaline earth metal is calcium. (3) The manufacturing method according to claim 1 or 2, wherein c is 50 to 500 and b is 1 to 7.