JP5098704B2 - Catalyst for the production of olefins from ketones - Google Patents

Description

  The present invention relates to a catalyst for producing olefins from ketones.

The present inventors have published a research report entitled “Production of olefins from biomass-derived acetone using a zeolite catalyst” (Non-patent Document 1). In this report, ZSM-5 type zeolite is used as a catalyst, but sufficient attention has not been paid to its crystal size. In general, the crystal diameter of zeolite is several hundred nm to several μm.
Proceedings of the 36th Petroleum and Petrochemical Discussion Meeting (November 30, 2006)

  As a result of researches on catalysts having excellent catalytic activity and high selectivity for olefins, the present inventors have succeeded in nano-sizing ZSM-5 type zeolite and further inactivate the acid sites on the outer surface of the crystal. The inventors succeeded in increasing the selectivity of olefins (especially propylene) produced by the conversion to the completion of the present invention.

That is, the first gist of the present invention, the crystal diameter Ri consists following ZSM-5 type zeolite 100 nm, and inert by surface treatment of the acid sites of the outer surface of the crystal by large silane compound than the pores of the zeolite It turned into and resides with the catalyst for producing olefins from ketones, wherein forming Rukoto.

In a preferred embodiment of the present invention, the crystal diameter is 60 nm or less.

And the 2nd summary of this invention exists in the manufacturing method of the olefin characterized by making ketones contact with the catalyst which concerns on said 1st summary.

  ADVANTAGE OF THE INVENTION According to this invention, it is a catalyst for manufacturing an olefin from ketones, Comprising: The catalyst which is excellent in catalyst activity and has high selectivity of an olefin is provided.

  First, for the convenience of explanation, the method for producing the catalyst of the present invention will be explained. The catalyst of the present invention comprises ZSM-5 type zeolite. In the present invention, the ZSM-5 type zeolite basically has a mother liquor containing at least an alumina source, a silica source and a template added to a surfactant and organic solvent solution to form an emulsion of the mother liquor. Thereafter, it can be produced by a method of hydrothermal synthesis. In a preferred embodiment of the present invention, a cation source is used as a stabilizer in preparing the mother liquor.

  The alumina source is not particularly limited, and examples thereof include aluminum alkoxide, aluminum chloride, aluminum sulfate, aluminum nitrate, aluminum oxide, aluminum hydroxide, sodium aluminate, alumina white, and aluminum fluoride. Among these, aluminum Alkoxides are preferred. Specific examples of the aluminum alkoxide include aluminum trimethoxide, aluminum triethoxide, aluminum triisopropoxide and the like.

  The silica source is not particularly limited, and includes silicon alkoxide, colloidal silica, wet silica, amorphous silica, fumed silica, sodium silicate, silica sol, silica gel, kaolinite, diatomaceous earth, aluminum silicate, white carbon and the like. Of these, silicon alkoxide is preferred. Specific examples of the silicon alkoxide include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane and the like.

  The template is not particularly limited, and tetrapropylammonium hydroxide (TPAOH), tetrapropylammonium bromide (TPABr), tetrabutylammonium hydroxide (TBAOH), tetramethylammonium hydroxide (TMAOH), tetramethylammonium chloride ( TMACl) and the like.

  The cation source is not particularly limited, and usually salts of various metals such as chlorides and sulfates of alkali metals and alkali metals are used. Specific examples thereof include sodium chloride, sodium sulfate and magnesium chloride. Usually, sodium chloride is used.

  The surfactant is not particularly limited, and examples thereof include anionic surfactants including sodium dodecyl sulfate, sodium dodecyl benzene sulfonate, sodium dodecyl naphthalene sulfate, dialkyl benzene alkyl, sulfate, sulfonate; dialkyl benzene alkyl ammonium. Cationic surfactants including chloride, alkylbenzylmethylammonium chloride, alkylbenzyldimethylammonium bromide, benzalkonium chloride, cetylpyridinium bromide, dodecylbenzyltriethylammonium chloride, laurylamine acetic acid, stearylamine acetate, and lauryltrimethylammonium chloride A zwitterionic surfactant containing lauryldimethylamine oxide; Alcohol, polyacrylic acid, metalrose, methylcellulose, ethylcellulose, propylcellulose, hydroxyethylcellulose, carboxymethylcellulose, tristyrylphenol ethoxylate phosphate ester, polyoxyethylene cetyl ether, polyoxyethylene lauryl ether, polyoxyethylene octyl ether, polyoxy Nonionic surfactants including ethylene octyl phenyl ether, polyoxyethylene oleyl ether, polyoxyethylene sorbitan monolaurate, polyoxyethylene stearyl ether, polyoxyethylene nonylphenyl ether, dialkylphenoxy poly (ethyleneoxy) ethanol, etc. Can be mentioned. In these, a nonionic surfactant, especially polyoxyethylene oleyl ether are preferable.

  Examples of the organic solvent include water-insoluble organic solvents such as aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons, ethers, halogenated hydrocarbons, esters, and the like. Specific examples of the aliphatic hydrocarbon include n-hexane, isohexane, n-heptane, isoheptane, liquid paraffin, n-octene, isooctene, gasoline, petroleum ether, kerosene, benzine, mineral spirit and the like. Specific examples of the alicyclic hydrocarbon include cyclopentane, cyclohexane, cyclohexene, cyclononane and the like. Specific examples of the aromatic hydrocarbon include benzene, toluene, xylene, ethylbenzene, n-propylbenzene, cumene, mesitylene, tetralin, styrene and the like. Specific examples of the ether include dipropyl ether and diisopropyl ether. Specific examples of the halogenated hydrocarbon include methylene chloride, chloroform, ethylene chloride, trichloroethane, trichloroethylene and the like. Specific examples of the ester include ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, n-amyl acetate, isoamyl acetate, n-butyl lactate, methyl propionate, ethyl propionate, and n propionate. -Butyl, methyl butyrate, ethyl butyrate, n-butyl butyrate and the like. Among these, alicyclic hydrocarbons are preferable, and cyclohexane is particularly preferable. Two or more of these organic solvents may be used in combination.

  In the solution of the surfactant and the organic solvent, the concentration (mol / L) of the surfactant in the organic solvent is 0.1 to 0.75 mol / L. In the mother liquor, the alumina source concentration is 0.004 to 0.125 mol / L, the silica source concentration is 0.4 to 2.5 mol / L, the Si / Al molar ratio is 20 to 200, and the Si / template molar ratio is 3. -10. The concentration of the cation source is usually 0.012 to 0.375 mol / L.

  First, in the present invention, a mother liquor is added to a solution of a surfactant and an organic solvent to form a mother emulsion microemulsion (O / W type). The formation of the microemulsion can be performed using various stirring devices including various homogenizers according to a conventional method.

  In the present invention, when a mother liquor is added to a solution of a surfactant and an organic solvent to form a microemulsion, it is important that the weight ratio of the mother liquor to the surfactant is in the range of 0.67 to 40. By selecting the weight ratio of the mother liquor to the surfactant within the above range, nano-sizing of the ZSM-5 type zeolite obtained by hydrothermal synthesis can be achieved, and the crystal diameter can be reduced to 100 nm or less.

  Next, in the present invention, hydrothermal synthesis is performed to obtain a ZSM-5 type zeolite. Generally, conditions for synthesizing ZSM-5 compounds can be adopted as conditions for hydrothermal synthesis. Specifically, an autoclave is used, and the treatment is usually performed at a temperature of 373 to 453 K, preferably 393 to 443 K for 10 to 100 hours, preferably 24 to 72 hours.

After hydrothermal synthesis, calcination is performed to remove the template. Further, since the zeolite after calcination is Na type, ion exchange is performed to H type as necessary. The conditions for removing the template and ion exchange are not particularly limited, and known conditions can be adopted. For removal of the template, for example, a muffle furnace can be used for firing. Further, ion exchange is preferably performed by a method of converting to H type via NH ₄ type.

  Next, the catalyst of the present invention will be described. The catalyst of the present invention is a catalyst for producing olefins from ketones, and is characterized by comprising a ZSM-5 type zeolite having a crystal diameter of 100 nm or less. The catalyst of the present invention can be obtained by the above production method. The crystal diameter can be measured by an SEM photograph (magnification 50,000), and the structure confirmation of the ZSM-5 type can be performed by X-ray diffraction measurement. In the present invention, the crystal diameter is preferably 60 nm or less. The lower limit of the crystal diameter is not particularly limited, but is actually 20 nm. As for the particle size distribution, about 90% of the particles are present in the crystal size range of 50 to 70 nm and are very monodispersed.

  The catalyst of the present invention has the following advantages. That is, in the conventional micro-sized zeolite catalyst, when the reaction proceeds at an acid point in the crystal, it tends to be diffusion-controlled, and the activity deterioration due to coking occurs. In contrast, the nanosized zeolite catalyst of the present invention is unlikely to deteriorate in activity. This is presumably because the outer surface area of the crystal is increased and the diffusion resistance of the raw material / product is reduced.

In the present invention, it is preferable to deactivate the acid sites on the outer surface of the crystal. For inactivation of acid sites on the outer surface, for example, surface treatment with various silane compounds larger than the pores of the zeolite, for example, various diphenylsilanes such as diphenylmethylsilane is suitable. For example, diphenylsilane is adsorbed on the surface of a ZSM-5 type zeolite in a nitrogen atmosphere and then calcined in air. Thereby, diphenylsilane chemically adsorbed on the acid sites of the zeolite is converted to silicon oxide (SiO ₂ ) on the acid sites.

  Specifically, the above method can be performed as follows. 0.5-2 g of H-ZSM-5 type zeolite was charged in a fixed bed type quartz reaction tube and calcined at 773 K for 1 hour in a nitrogen atmosphere. Thereafter, the temperature is lowered to 373 K in a nitrogen stream, diphenylsilane is supplied, and the zeolite and diphenylsilane vapor are brought into contact with each other. At this time, a partial pressure of diphenylsilane in a nitrogen stream is 1 to 10%, and a contact time of 30 to 90 minutes is sufficient. Next, the supply of diphenylsilane is stopped and the temperature is raised to 723-873K in a nitrogen stream. At this time, the heating rate is preferably 1 to 10 K / min. Then, it is baked in the same atmosphere for 20 to 90 minutes to immobilize the silane compound on the acid sites on the outer surface of the zeolite. The atmosphere gas is switched from nitrogen to air and baked at the same temperature for 30 to 120 minutes to remove the carbon component. The above series of operations is preferably repeated a plurality of times (for example, 2 to 6 times).

  The catalyst of the present invention in which the acid sites on the outer surface are deactivated has the following advantages. That is, when the acid sites on the outer surface are used for the reaction, there is no spatial restriction, and therefore aromatic hydrocarbons are easily generated. In contrast, when the acid sites on the outer surface of the crystal are deactivated, the acid sites in the crystal pores are used for the reaction, so that the production of aromatic hydrocarbons is suppressed and the olefins produced (particularly propylene) ) Is increased.

  Next, the manufacturing method of the olefin which concerns on this invention is demonstrated. The production method of the present invention is characterized in that a catalyst and a ketone are brought into contact with each other. Typical examples of the starting ketones include acetone and methyl ethyl ketone. In particular, acetone derived from biomass is suitable.

For the production reaction of olefins, for example, a method using a fixed bed flow reactor and allowing gasified ketones to flow through and contact with the catalyst can be employed according to a conventional method of catalytic reaction. The reaction temperature is usually 523 to 873 K, and the feed rate (SV) of the raw material gas is usually 1000 to 100,000 h ⁻¹ . The concentration of the raw material gas is usually 0.1 to 10,000 ppm. Usually, nitrogen is used as a gas for adjusting the concentration (carrier gas).

  EXAMPLES Hereinafter, although an Example demonstrates this invention still in detail, this invention is not limited by a following example, unless the summary is exceeded.

Example 1:
[Manufacture of catalyst]
<Manufacture of nanocrystal ZSM-5 type zeolite>
Aluminum isopropoxide (alumina source: Wako Pure Chemical Industries, 95.0%) 0.5145 g, sodium chloride (cation source (stabilizer): Wako Pure Chemical Industries, 99.5%) 0.442 g, tetrapropylammonium hydroxide (template: manufactured by Wako Pure Chemical Industries, Ltd., 10% aqueous solution) and 129.5 g of distilled water were mixed and then stirred to confirm that the aqueous solution was uniform. 42 g of tetraethoxysilane (silica source: 95.0%, manufactured by Wako Pure Chemical Industries, Ltd.) was added and stirred at room temperature for 24 hours to obtain a SiO ₂ -template complex (mother liquor).

  On the other hand, polyoxyethylene (15) oleyl ether (nonionic surfactant: manufactured by Nippon Surfactant Kogyo Co., Ltd.) and cyclohexane (organic solvent: manufactured by Wako Pure Chemical Industries, Ltd., 99.5%) were used. 1960 ml of a surfactant / organic solvent solution having a surfactant concentration of 0.5 mol / L was prepared.

  Next, the above surfactant / organic solvent solution was kept in a 323 K water bath, and 280 ml of the mother liquor was dropped in small portions over about 1 hour. Then, the system was made uniform by stirring for 1 hour as it was, and then transferred to an autoclave, and hydrothermal synthesis was performed at 393 K for 24 hours.

  After hydrothermal synthesis, it was cooled to room temperature, transferred to a beaker, and the pH was adjusted to 7-8 using nitric acid to increase the yield. At this time, a granular material was deposited. Thereafter, a small amount of 2-propanol was added and the mixture was stirred and washed for 5 minutes, and then the nanocrystal ZSM-5 type zeolite was recovered as a precipitate by centrifugation (2500 rpm, 10 minutes). The above stirring and washing / centrifugation operation was repeated a total of 3 times. As a result of SEM photography, the average particle size of the zeolite was 50 nm. The structure of the ZSM-5 type was confirmed by X-ray diffraction measurement.

  Next, the zeolite obtained above was dried overnight in a 373 K dryer, and then calcined in a muffle furnace to remove the remaining template, thereby obtaining a Na-type zeolite. At this time, the temperature rising process was (1) temperature rising from room temperature to 623K over 3 hours, (2) holding at 623K for 8 hours, (3) temperature rising from 623K to 773K over 3 hours, (4) at 773K. It was carried out so as to hold for 6 hours.

<Ion exchange>
Next, it was converted into H-type zeolite of Na-type zeolite according to the following procedure. That is, a 10 wt-fold amount of a 5 wt% ammonium nitrate aqueous solution was added to Na-type zeolite, stirred for about 8 hours under reflux conditions in a 373 K hot bath, and then the supernatant and zeolite were separated by centrifugation. This stirring / centrifugation treatment was repeated a total of 3 times. At this time, the concentration of the ammonium nitrate aqueous solution was gradually increased so as to be 5 wt% → 8 wt% → 10 wt%. Next, after washing with a sufficient amount of distilled water for about 1 hour, the washing operation of separating the supernatant and zeolite by centrifugation was repeated three times in total, and then dried in a 373 K dryer for about 12 hours. Then, it was baked in a muffle furnace for 4 hours at 773 K to convert the NH ₄ type into the H type and sufficiently remove moisture remaining in the pores. The heating rate during firing was 0.5 K / min.

[Olefin production]
<Reactor>
The fixed bed flow reactor shown in FIG. 1 was used. This apparatus is roughly arranged in a cylindrically shaped catalyst reactor (1), a zeolite catalyst (2) accommodated in the catalyst reactor, an outer peripheral side of the catalyst reactor (1), and the catalyst A heater (3) for heating the reactor, supplying ketones together with the carrier gas to the catalyst reactor (1), and contacting the ketones with the zeolite catalyst (2) while heating the catalyst reactor (1) Thus, an olefin is produced, and the obtained olefin is taken out from the catalytic reactor (1).

  Specifically, the catalytic reactor (1) includes a cylindrical container (10) having heat resistance and corrosion resistance, and a cylindrical container (1) divided into a state in which the center line of the cylindrical container is divided. Comprising a porous structure dish (11), (11) constituting a catalyst housing part in the central part of the catalyst, and in the catalyst housing part between these eye dishes (11), (11), a zeolite catalyst (2) Is housed. A raw material supply pipe (5) is connected to one end of the catalyst reactor (1), and a product extraction pipe (7) is connected to the other end of the catalyst reactor (1).

  A pipe (51) that extends from a microsyringe (not shown) and supplies ketones as a raw material is connected to the upstream part of the pipe (5), and a dilution part is connected to the upstream part of the pipe (5). A pipe (52) for supplying carrier gas for use and transfer is connected. Such a pipe (52) is connected from an inert gas container (not shown) such as nitrogen to the pipe (5) via a flow rate adjusting valve (61) and a flow meter (62). That is, the catalyst reaction vessel (1) introduces ketones that are quantitatively supplied from the microfeeder and diluted with nitrogen at a constant flow rate from the pipe (5), and the olefin obtained by the catalytic reaction is introduced into the pipe (7). It is made to take out from.

  As the heater (3), a block heater or the like that includes a cylindrical heating unit and can accommodate the catalytic reaction vessel (1) in the cylindrical heating unit is used. In the cylindrical heating part of the heater (3), a temperature sensor (4) for detecting the heating temperature of the catalytic reaction vessel (1) is disposed, and the heater (3) is provided by a separately provided temperature controller. Based on the temperature detected by the temperature sensor (4), the energization is controlled so that the temperature of the catalyst reaction vessel (1) becomes the set temperature. Note that a tape heater (8) for preheating the raw material is wound around the upstream pipe (5) of the catalytic reactor (1), and the downstream pipe (7) of the catalytic reactor (1) (7). ) May be wound with a tape heater (9) for preventing condensation.

<Reaction conditions>
The reaction was performed under the conditions shown in Table 1 using the above reaction apparatus. The analysis of the reaction gas was performed by gas chromatography (“GC8A” manufactured by Shimadzu Corporation: detector FID). As the column, a Polapack packed column “Polapack Q” (80 to 100 mesh: 3 m) manufactured by GL Sciences Inc. was used. The analysis conditions were column temperature: 323 to 503 K (3 K / min temperature increase), sample vaporization chamber and detector (INJ / DET) temperature: 503 K.

<Reaction result>
The reaction results were as shown in Table 2 below.

Example 2:
[Manufacture of catalyst]
H-ZSM-5 type zeolite was obtained in the same manner as in Example 1, and acid sites on the outer surface thereof were inactivated using diphenylmethylsilane in the following manner.

<Inactivation of acid points on the outer surface>
The outer surface acid sites of the H-ZSM-5 type zeolite obtained in Example 1 were inactivated by the following method. That is, first, 1 g of H-ZSM-5 type zeolite was filled in a fixed bed type quartz reaction tube and calcined for 1 hour at 773 K in a nitrogen atmosphere. Thereafter, the temperature was lowered to 373 K in a nitrogen stream, diphenylsilane was supplied, and the zeolite and the diphenylsilane vapor were brought into contact with each other. At this time, the partial pressure of diphenylsilane in the nitrogen stream was 2%, and the contact time was 60 minutes. Next, the supply of diphenylsilane was stopped, and the temperature was raised to 773 K in a nitrogen stream. At this time, the temperature rising rate was 5 K / min. And it baked in the same atmosphere for 60 minutes, and fixed the silane compound on the acid point of the outer surface of a zeolite. The atmosphere gas was switched from nitrogen to air and calcinated at the same temperature for 90 minutes to remove the carbon component. The above series of operations was repeated three times.

[Olefin production]
Olefin was produced in the same manner as in Example 1, and the reaction gas was analyzed.

<Reaction result>
The reaction results were as shown in Table 3 below.

Comparative Example 1:
Olefin was produced in the same manner as in Example 1 except that microsized H-ZSM-5 type zeolite (1 μm) synthesized under ordinary hydrothermal synthesis conditions was used as a catalyst, and reaction gas was analyzed.

<Reaction result>
The reaction results were as shown in Table 4 below.

Schematic diagram of a reactor for the production of olefins used in the examples and comparative examples

Explanation of symbols

1: catalyst reactor 2: zeolite catalyst 3: heater 4: temperature sensor 5: piping 51: piping 52: piping 61: flow rate adjusting valve 62: flow meter 7: piping 8: tape heater 9: tape heater 10: cylinder Container 11: Eye plate

Claims (4)

Crystal diameter Ri consists following ZSM-5 type zeolite 100 nm, and, ketones acid sites of the outer surface inactivated by surface treatment with a large silane compound than the pores of the zeolite characterized by forming Rukoto crystals For the production of olefins from coal.   The catalyst according to claim 1, wherein the crystal diameter is 60 nm or less. The catalyst according to claim 1 or 2, wherein the silane compound is diphenylsilane . A method for producing an olefin, comprising contacting the catalyst according to any one of claims 1 to 3 with a ketone.

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