JPH09100244A - Production of olefin compound and dehydration reaction catalyst therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an olefin compound from an alcohol compound without raising problems of by-products due to oligomerization, difficulty of separating the product from steam, catalyst poisoning due to water, limitation of material for the relevant apparatus, etc. SOLUTION: This olefin compound is obtained by dehydration reaction of a secondary or tertiary alcohol using vanadosilicate as catalyst in the presence of oxygen at 150-350 deg.C under normal pressures to 20kg/cm<2> . The vanadosilicate catalyst, as it is not an acidic catalyst, advances the dehydration reaction alone in high selectivity, causing virtually no dimerization, etc., of the olefin compound formed, therefore obtaining the objective olefin compound in high purity and yield. The vanadosilicate is a kind of zeolite with vanadium cations substituted for part of the silicate skeleton; mesoporous vanadosilicate, a specific kind thereof, is btained by hydrothermal treatment in an autoclave of a mixture comprising silicon oxide as silicon source, a vanadium compound as vanadium source, and a surfactant as template.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for producing olefins by dehydrating alcohols, particularly secondary or tertiary alcohols in the presence of a catalyst and oxygen, and a dehydration catalyst used therefor. Regarding

[0002]

2. Description of the Related Art Heretofore, in the case of producing olefins from alcohols by dehydration reaction, generally, an acidic catalyst is often used. That is, as a method for dehydrating the alcohol in the liquid phase, it is general to carry out in a homogeneous system using sulfuric acid or the like, but in a heterogeneous liquid phase using a strongly acidic ion exchange resin having a sulfonic acid group. There is also known a method of dehydration in JP-A-54-135710 and JP-A-54-13506.

On the other hand, a dehydration method using a solid acid as a catalyst in a gas phase is also known, for example, a method using solid phosphoric acid (US Pat. No. 4,036,095) and a method using activated alumina (Japanese Patent Publication No. Sho 50). -12403) and the like have been reported.

However, the above-mentioned dehydration method using an acid catalyst has a drawback that the olefins produced from alcohols are increased in quantity due to the acid nature of the catalyst, resulting in a decrease in the yield of olefins. .

In order to improve the difficulty of producing by-products due to the large amount, a method of mixing a non-reactive gas and / or steam into the reaction system (Japanese Patent Laid-Open No. 63-41431) or a new catalyst such as niobate is used. The method used (JP-A-1-290636) has been proposed.

Although the above-mentioned method solves the problem of by-product formation due to multimerization, another problem has been pointed out. That is, JP-A-63-
The method described in No. 41431 is a method of using silica-alumina, which is one of acid catalysts, as a catalyst and mixing a non-reactive gas and / or steam into the reaction system. However, when steam is mixed, the product is separated. However, the drying process becomes complicated, which is economically disadvantageous.

On the other hand, the method described in Japanese Patent Application Laid-Open No. 1-290636 has the characteristic that the production of by-products due to the dimerization of olefins is scarcely observed, but the water produced by the dehydration reaction causes the catalyst niobic acid Poisoned,
In addition to the drawback that the activity is lowered, niobic acid is an acidic substance, so that it is necessary to take measures against corrosion of the device, and there is a problem that an acid resistant material must be used.

[0008]

Therefore, when olefins are produced from alcohols by dehydration reaction, problems such as by-products due to multimerization, difficulty in separating products from water vapor, and catalysts with water There has been a demand for providing a new method that does not cause problems such as poisoning or restrictions on the material of the device.

[0009]

[Means for Solving the Problems] In the method for producing olefins by subjecting alcohols to a dehydration reaction, the present inventors have solved the problems of the above-mentioned conventional methods and applied to a wide range of raw material alcohols. We have studied earnestly to find a way to do it. As a result, they have found that by using a specific catalyst in the presence of oxygen, the raw material alcohols can be efficiently dehydrated and converted into olefins without the problems found in the conventional methods. It was also found that this method has a high selectivity of olefins because side reactions such as multimerization hardly occur, and can be applied to a wide range of raw material alcohols.

The present invention has been completed based on the above findings, and in a method for producing olefins by dehydration reaction using secondary or tertiary alcohols as raw materials, vanadosilicate is used as a catalyst. The present invention provides a method for producing olefins, which comprises dehydrating in the presence of oxygen. The present invention also provides a dehydration reaction catalyst that can be used in the above reaction.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION In the method of the present invention, secondary or tertiary alcohols (hereinafter sometimes referred to as "raw material alcohol") are used as raw materials. The raw material alcohol preferably has 4 to 16 carbon atoms, and any raw material alcohol selected from chain aliphatic, cycloaliphatic and aromatic alcohols can be used.

Of the raw material alcohols, specific examples of secondary alcohols include secondary butyl alcohol, secondary pentyl alcohol, secondary hexyl alcohol,
Examples thereof include cyclohexyl alcohol, 1-menthol, α-phenylethyl alcohol (α-phenethyl alcohol) and the like. Further, specific examples of the tertiary alcohols include tertiary butyl alcohol, tertiary pentyl alcohol, tertiary hexyl alcohol, tertiary heptyl alcohol, cumyl alcohol and the like.

The dehydration reaction catalyst used in the present invention contains vanadosilicate. Vanadosilicate is a kind of zeolite in which a part of skeleton of silicate is replaced with vanadium cation.

An example of this vanadosilicate is, for example, J. Chem. Soc. Chem. Commu.
n., 1994, 1059. and the like, which include mesoporous vanadosilicates. This mesoporous vanadosilicate (hereinafter sometimes referred to as "V-MCM-41") is a silicon source containing silicon oxide,
It is obtained by subjecting a vanadium compound as a vanadium source and a surfactant as a template to hydrothermal treatment of these in an autoclave.

This V-MCM-41 can have different pore sizes by changing the molar ratio of the surfactant and silicon oxide at the time of production. In addition, by changing the addition amount of vanadium compound, V-MCM
The vanadium content in -41 can also be adjusted.

The V-MCM-41 thus obtained has tunnel-like pores having a diameter of 20 to 100 angstroms, which are called mesopores, and has a specific surface area of 500 to 1
It is an extremely large value of 200 m ² / g.

The vanadosilicate used in the method of the present invention is preferably mesoporous vanadosilicate such as V-MCM-41, but is not limited thereto, and those having various pore diameters or specific surface areas can be used.
In vanadosilicate used as a dehydration reaction catalyst, the presence and content of vanadium affect the conversion rate and selectivity of the dehydration reaction, which is important. In general, vanadium is 0.01 to 10 wt% in vanadosilicate.
%, Particularly 0.2 to 5 wt
It is preferably contained in the range of%.

As the dehydration reaction catalyst of the present invention, the above-mentioned vanadosilicate may be used as it is, or may be used by supporting it on a suitable carrier such as silica.
Also, the shape thereof may be any shape and size such as a granular shape, a pellet shape, and a cylindrical shape.

The reaction mechanism of the method of the present invention is currently unknown, but the presence of oxygen is essential. Although it is practically advantageous to use air as the oxygen source, it is of course possible to use oxygen diluted with another inert gas such as nitrogen. The oxygen concentration at this time is not particularly limited, but is generally 0.1 to 100 vol%.

Various methods can be used for carrying out the method of the present invention. That is, it is possible to use any of the fixed bed type or fluidized bed type, continuous type or batch type.

The reaction in the present invention is usually carried out in the gas phase. However, if desired, the reaction can also be carried out under conditions which maintain the liquid phase under pressure. The reaction temperature is not particularly limited, but is generally 150 to 350.
A temperature of about 0 ° C, preferably about 200 to 320 ° C is adopted. The reaction pressure is not particularly limited, but is usually atmospheric pressure to 20 kg / cm ² , preferably atmospheric pressure to 10 kg.
/ Cm ² is taken.

In the method of the present invention, the feed rate of the alcohol as a raw material varies depending on the volume of the catalyst, the type of alcohol, the temperature, the pressure, etc.
50 / hr, especially 0.5-15 / hr are suitable.
The oxygen supply rate is 10 to 30000 / GHSV.
hr, preferably 200 to 2000 / hr.

For the supply of oxygen in carrying out the method of the present invention, the raw material alcohols and oxygen can be separately sent to the catalyst layer, but the raw material alcohols preliminarily heated and gasified and oxygen are mixed in advance, More preferably, it is introduced into the catalyst layer. Further, in carrying out the invention, a diluent may not be particularly used, but if necessary, an inert gas such as nitrogen or steam may be added to the reaction system.

According to the method of the present invention described above, almost all secondary or tertiary alcohols can be used as the raw material alcohol, and the olefins obtained by the dehydration reaction thereof can be used as various chemical raw materials. . For example, isobutylene is obtained from t-butyl alcohol, which is a chain aliphatic alcohol, and is useful as a raw material for polymers such as butyl rubber. Cyclohexanol, which is a cycloaliphatic alcohol, gives cyclohexene, which is useful as a raw material for l-lysine. Furthermore, styrene is obtained from α-phenethyl alcohol which is an aromatic alcohol,
This can be used as a resin raw material such as polystyrene and ABS resin.

As described above, the reaction mechanism by which highly pure various olefins can be obtained from secondary or tertiary alcohols in good yield by using vanadosilicate as a catalyst of the present invention is not clear. However, it is surprising that vanadosilicate, which does not exhibit the properties of a solid acid catalyst, exhibits a high activity in the dehydration reaction of alcohols in the presence of oxygen. Since the vanadosilicate catalyst used in the present invention is not an acidic catalyst, only the dehydration reaction of alcohols proceeds with high selectivity to produce 2
It is extremely excellent in that quantification is hardly observed.
Further, naturally, it is also excellent in corrosiveness with respect to the device.

[0026]

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. In the following examples,% means% by weight.

Example 1 (1) Preparation of catalyst 32.2 g of Aerosil 200 (manufactured by Nippon Aerosil Co., Ltd.), which is a kind of silica, was put into a caustic soda aqueous solution and dissolved.
Stir for 30 minutes. Then, 20 g of a 20% vanadyl sulfate aqueous solution was added thereto, and the mixture was stirred for 3 hours. Further, 86.7 g of cetyltrimethylammonium bromide was added as a template and stirred for 1 hour. The obtained mixture was put into a 500 ml Teflon-lined stainless steel autoclave and heated at 100 ° C. for 96 hours.

The solid formed by crystallization was filtered and then washed with water. After drying it at 60 ° C for 24 hours,
It baked at 0 degreeC for 6 hours, and obtained V-MCM-41. The thus obtained V-MCM-41 had a Si / V / Na ratio (atomic ratio) of 67.5 / 1 / 0.84, a specific surface area (BET method) of 877 m ² / g and an average fineness. The pore size was 27 Å.

With respect to the obtained V-MCM-41, the adsorption of pyridine was measured by the "pyridine thermal desorption method" (pyridine TPD). The results are shown in FIG. 1. As is clear from this figure, no chemisorption of pyridine was observed, and thus it was shown that this V-MCM-41 did not show acidity.

(2) Dehydration reaction of alcohol V-MCM-41 200 mg prepared in the above (1)
Quartz reaction tube (length 180m) with (1.0ml) as catalyst
m, inner diameter 8 mm), and while heating the reaction tube with an electric furnace, t-butyl alcohol and air were supplied under normal pressure. Each supply rate is 0.5g / hr (LH
SV = 0.65 / hr) and 900 ml / hr (GH
SV = 900 / hr), and the central temperature of the catalyst layer was kept at 270 ° C. during the feeding.

The reaction gas was condensed in a cooling trap and the recovered liquid was analyzed by gas chromatography.
The conversion of t-butyl alcohol was 98.4%.
No by-products such as diisobutylene were observed, and the selectivity of isobutylene reached 99.5%. Therefore, the yield of isobutylene is 97.9%.

Comparative Example 1 200 mg of normal silica containing no vanadium (Silica gel 60 manufactured by Merck) was used as a catalyst.
The dehydration reaction of t-butyl alcohol was performed under the same conditions as above. The conversion of t-butyl alcohol is 1% or less,
It showed little activity.

Example 2 V-MCM-41 prepared in Example 1 (1) as a catalyst
With cyclohexanol as alcohol 3.6
The dehydration reaction was carried out in the same manner as in Example 1 except that the catalyst was supplied at g / hr (LHSV = 3.7 / hr) and the central temperature of the catalyst layer was 300 ° C. As a result of trapping and analyzing the reaction gas, the conversion of cyclohexanol was 98.6%. The selectivity of cyclohexene was 99.8%. Therefore, the yield of cyclohexene is 98.4%.

Comparative Example 2 The dehydration reaction was carried out in the same manner as in Example 2 except that nitrogen gas was supplied at 900 ml / hr instead of air together with the supply of cyclohexanol. As a result of analysis by trapping the reaction gas, the conversion of cyclohexanol was as low as 3.2%, and the selectivity of cyclohexene was 25.0%. From this, it can be said that air is indispensable for this reaction.

Examples 3 to 6 The dehydration reaction was carried out in the same manner as in Example 1 using various starting alcohols. Table 1 shows each condition of the reaction, and Table 2 shows the result of the dehydration reaction.

[0036] 1) A solution prepared by dissolving 25 g of 1-menthol in 75 g of benzene was used.

[0037] As is clear from this result, according to the method of the present invention, the conversion rate of alcohol is high, and the corresponding olefin can be obtained in high yield.

Example 7 (1) Preparation of catalyst V-MCM was carried out in the same manner as in Example 1 (1) by changing the raw material ratio.
-41 was prepared. Si / of the obtained V-MCM-41
The V / Na ratio (atomic ratio) was 36.1 / 1 / 0.78. The specific surface area (BET method) was 848 m ² / g.

(2) Alcohol dehydration reaction In the same manner as in Example 1, cyclohexanol was dehydrated. The conversion of cyclohexanol was 97.3% and the selectivity of cyclohexene was 98.8%. Therefore, the yield of cyclohexene is 96.1%.

[0040]

EFFECTS OF THE INVENTION According to the method of the present invention, there are problems such as by-products due to multimerization, difficulty in separating products from water vapor, poisoning of catalysts by water, and restrictions on equipment materials. Olefins can be produced from raw alcohols without generation.

The present method can be applied to dehydration reaction of a wide variety of raw material alcohols,
Only the dehydration reaction of alcohols proceeded with high selectivity at an extremely high conversion rate, and dimerization of olefins produced was hardly observed.
It is extremely excellent in that it can be obtained in high yield.

[Brief description of the drawings]

FIG. 1 is a drawing showing the results of measuring the adsorption of pyridine on V-MCM-41 obtained in Example 1. that's all

Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI Technical display area C07C 13/20 6958-4H C07C 13/20 15/44 6958-4H 15/44 15/46 6958-4H 15 / 46 // C07B 61/00 300 C07B 61/00 300

Claims (4)

[Claims] 1. A method for producing an olefin by a dehydration reaction using a secondary or tertiary alcohol as a raw material, wherein vanadosilicate is used as a catalyst and dehydrated in the presence of oxygen. Manufacturing method. 2. The method for producing olefins according to claim 1, wherein the vanadosilicate is mesoporous vanadosilicate. 3. A dehydration reaction catalyst containing vanadosilicate. 4. The dehydration reaction catalyst according to claim 3, which is used for producing olefins from secondary or tertiary alcohols.