JP2008289991A - Catalyst for synthesis of propylene - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a novel, industrially advantageous catalyst enabling the synthesis of propylene by an ethanol conversion reaction with an improved selectivity and an improved ethanol conversion rate. <P>SOLUTION: The catalyst for synthesis of propylene contains a porous solid oxide modified with a compound containing a metal(s) of the group VI and/or the VII in the periodic table and is used to synthesize propylene by conversion of ethanol. Another catalyst for synthesis of propylene containing a porous solid oxide which is modified with compound containing a metal(s) of the group VI and/or the VII and additionally with an element selected from elements of the group XV and/or rare earth elements in the periodic table. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a novel catalyst used for synthesizing propylene by converting ethanol.

Typical production methods for propylene, the key material of the chemical industry using petroleum as a raw material, are 1) steam decomposition of naphtha at around 900 ° C, 2) propane dehydrogenation or oxidative dehydrogenation, etc. It is.
On the other hand, it is expected that development of a method for producing propylene from non-petroleum-based raw materials, particularly biomass-derived alcohol, will become more and more necessary in the future due to concerns about the exhaustion of petroleum resources. Propylene raw material is also promising as a raw material for fermentation, and in addition to this, 1,2-propanediol by fermentation and glycerin, a by-product of biodiesel production, are assumed as raw materials. .

However, although an example of propylene synthesis by monohydric isopropanol dehydration is known (Patent Document 1), in the production from ethanol, it is necessary to control reactions such as dehydration / dimerization / disproportionation, which is difficult. The degree is high.
For example, propylene production from ethanol using a single H-ZSM5 as a catalyst has been reported, but C5 + hydrocarbons containing aromatics (Non-Patent Document 1) and propane (Non-Patent Document 2) are the main products. Yes, the ethanol conversion and propylene selectivity were not satisfactory.

US Pat. No. 6,441,262 J. Chem. Tech. Biotech., 77, 211-216 (2002). Catal. Lett., 31, 395-403 (1995).

  An object of the present invention is to provide an industrially advantageous new propylene synthesis catalyst capable of synthesizing propylene with increased selectivity and ethanol conversion by an ethanol conversion reaction.

As a result of intensive studies on various catalyst groups in order to solve the above problems, the present inventors have completed the present invention.
That is, according to this application, the following invention is provided.
<1> Propylene used to synthesize propylene by converting ethanol, comprising a porous solid oxide modified with a compound containing a metal belonging to Group 6 and / or Group 7 of the Periodic Table Catalyst for synthesis.
<2> A porous solid oxide modified with a compound containing a metal belonging to Group 6 or Group 7 of the periodic table is further modified with an element belonging to Group 15 of the periodic table and / or rare earth The catalyst for propylene synthesis as described in <1> above.
<3> The catalyst for propylene synthesis as described in <1> or <2> above, wherein the porous solid oxide is a zeolite compound.
<4> The catalyst for propylene synthesis as described in <1> or <2> above, wherein the porous solid oxide is a sulfate group-modified metal oxide.
<5> The propylene synthesis catalyst according to any one of <1> to <4>, wherein the ethanol is bioethanol obtained by fermentation.

  If the novel catalyst of the present invention is used, propylene can be synthesized from an ethanol raw material such as bioethanol in one step with increased selectivity and conversion.

  The catalyst for propylene synthesis used when synthesizing propylene by converting ethanol of the present invention is a porous solid oxide modified with a compound containing a metal belonging to Group 6 and / or Group 7 of the Periodic Table. It is characterized by containing.

  The porous solid oxide includes any oxide as long as it can coexist with a compound containing a Group 6 and / or Group 7 metal in the periodic table or can carry a compound containing these metals on the surface thereof. .

Examples of such porous solid oxides include zeolite compounds.
Examples of the zeolite compound include Y-type, L-type, mordenite, ferrierite, beta-type, and H-ZSM-5.
Examples of the porous oxide other than the zeolite compound include crystalline metallosilicates such as TS-1, MCM-41, MCM-22, MCM-48, and gallosilicate, and large-diameter silica compounds.

  These porous oxides include those containing elements such as titanium, aluminum, vanadium, niobium, tantalum, boron, zirconium, and amorphous porous silica compounds.

  Examples of other porous solid oxides include oxides obtained by surface modification of commonly used metal oxides such as silica, alumina, zirconia, titania and ceria with sulfate radicals. It is also possible to use an oxide obtained by modifying a composite oxide such as silica-alumina with a sulfate group. Among these porous solid oxides, sulfate zirconia oxide is particularly preferable.

  A porous solid oxide particularly preferably used in the present invention is a zeolite compound having a small silica / alumina ratio (especially H, which can adsorb ethanol on the surface and supply protons to the OH groups of ethanol to promote dehydration. -ZSM5) and sulfate radical zirconia having solid superacidity.

The porous solid oxide used in the present invention needs to be modified with a compound containing a metal belonging to Group 6 and / or Group 7 of the periodic table before use.
As a modification method, a method of containing a compound such as tungsten in a solid oxide and firing in air is adopted.

  Here, the compound containing a metal belonging to Group 6 and / or Group 7 of the periodic table means a compound containing at least one metal of chromium, molybdenum, tungsten, manganese, and rhenium.

Typical examples of the compound containing a metal belonging to Group 6 and / or Group 7 of the periodic table include a tungsten compound, a rhenium compound, a molybdenum compound, and the like, and the tungsten compound includes a halogenated compound such as tungsten chloride. Tungsten, 12-tungstic acid (10-) ammonium decahydrate, tungstic acid cation compounds such as ammonium metatungstate, 12-tungstic acid (10-) potassium 10 hydrate, dodecatungstophosphoric acid (3-) 14 hydration And tungsten metal hetero compounds such as dodecatungstosilicate (4-) 26 hydrate, organometallic tungsten compounds such as hexacarbonyltungsten and hexamethyltungsten (VI), and the like.
Examples of the rhenium compounds include inorganic acid salts such as nitrates and sulfates, halides such as chlorides and bromides, rhenic acid compounds such as potassium hexachlororhenate, rhenates such as ammonium perrhenate, decacarbonyl dirhenium (0 ), Organometallic rhenium compounds such as pentacarbonylmethylrhenium, and the like.
Also, molybdenum compounds include halides such as molybdenum chloride, molybdenum complex compounds such as 2 molybdenum acetate, organometallic molybdenums such as hexacarbonylmolybdenum (0), sodium molybdate, 7- (6-) ammonium molybdate 4 Examples include molybdate cationic compounds such as hydrates, dodecaboribdophosphoric acid (3-) 30 hydrate, dodeca and dodecamolybdo compounds such as (3-) ammonium ribdophosphate.

As a method for incorporating a compound such as tungsten into the porous solid oxide, a conventionally known method such as a physical mixing method, an impregnation method, a precipitation method, a kneading method, or an incipient wetness method can be employed.
For example, a compound such as tungsten is usually supported on a solid oxide as an aqueous solution. Organic solvents such as acetone, isopropanol, and benzene are also used. The firing temperature of the zeolite oxide or the like containing a compound such as tungsten is about 300 to 900 ° C., preferably about 500 to 700 ° C. The supported amount of tungsten or the like is arbitrary, but it is 0.001 to 50 g, preferably 1 to 20 g per 100 g of the carrier oxide as tungsten metal. These additives can be used alone or as a mixture of two or more. In particular, the tungsten element belonging to Group 6 is particularly preferable because it promotes dimerization of an ethylene intermediate produced by dehydration of ethanol.

In the present invention, the porous solid oxide modified with the compound containing a metal belonging to Group 6 or 7 of the periodic table described above is further modified with an element belonging to Group 15 of the periodic table and / or a rare earth. You can also
For example, a fired porous solid oxide (W / porous solid oxide) carrying a compound such as tungsten may be further modified with a compound containing a metal belonging to Group 15 and / or an element belonging to a rare earth. it can.
Phosphorus is preferred as the atom belonging to Group 15, and lanthanum, cerium, europium, samarium, dysprosium, gadolinium, etc. are usually used as the rare earth. These can be used alone or in combination.
Examples of the phosphorus-containing compound include phosphorus halides such as phosphorus trichloride, phosphoric acids such as phosphoric acid, phosphonic acid and pyrophosphoric acid, and phosphate cation compounds such as ammonium phosphate.
In addition, rare earth compounds such as lanthanum include inorganic acid salts such as nitrates and sulfates, halides such as chlorides and bromides, organic acid salts such as oxalates and acetates, tris (2,4-pentadionato) lanthanum and the like. Examples thereof include organic coordination compounds.
The addition amount of the phosphorus compound and the rare earth material is arbitrary, but the phosphorus compound is 0.01 wt% to 100 wt%, preferably 0.1 wt% to 2 wt%, and the rare earth metal is 0.01 wt% with respect to the solid oxide support. ˜100 wt%, preferably 0.1 wt% ˜5 wt%.

  The propylene synthesis catalyst of the present invention can be prepared by (i) a method in which a porous solid oxide such as zeolite or sulfate radical zirconia-based material as a support is impregnated at once with a solution containing all modifiers, (B) A method of dropping a modifier solution containing all components into the porous solid oxide (incipient wetness method), (c) A method of mixing the porous solid oxide with all modifier components, (D) Three steps: (i) calcination after supporting tungsten or rhenium on a porous solid oxide, (ii) calcination after supporting a rare earth metal such as lanthanum, (iii) calcination after supporting a phosphorus compound, etc. The method of preparing by, etc. are illustrated. The firing temperature performed in any of the methods (a) to (d) is 300 to 1500 ° C, preferably 500 to 900 ° C.

  As ethanol used in the present invention, not only reagent-grade ethanol but also ethanol containing water, bioethanol by fermentation and the like are used. The water content in this case is arbitrary, but 0 wt% to 50 wt%, preferably 0 wt% to 15 wt% is used.

In the present invention, in order to synthesize propylene, ethanol may be subjected to propylene conversion reaction in the presence of the aforementioned catalyst.
In this synthesis reaction, as shown in the following reaction formula, propylene is obtained as a main product, but in addition, ethylene, butenes, C1 to C10 saturated hydrocarbons, benzene / toluene / xylene, etc. Aromatics and water are produced.
[Chemical 1]
C ₂ H ₅ OH → C ₃ H ₆ + C ₂ H ₄ + C ₄ H ₈ + C _n H _{2n + 2} (n = 1-10) + C ₆ H ₆ + C ₇ H ₈ + C ₈ H ₁₀ + H ₂ O (1) (coefficient not considered)

  The propylene production mechanism is not clear at this time, but ethanol dehydration reaction (ethylene production reaction) / dimerization reaction (butylene production reaction) / disproportionation reaction (propylene disproportionation reaction of ethylene and butylene) This is thought to be due to a complex reaction such as production).

The propylene synthesis reaction of the present invention can be carried out either in the gas phase or in the liquid phase, but since the boiling point of ethanol is lower than that of water, it is usually carried out in a gas phase system. In this case, the reaction temperature is 50 to 700 ° C., preferably 300 to 500 ° C., and the reaction pressure is arbitrary, and is 0.01 MPa to 100 MPa, preferably 0.05 MPa to 5 MPa.
Usually, ethanol is introduced into the catalyst layer together with a diluent gas, and an inert gas such as nitrogen or argon, CO ₂ or water vapor is used as the diluent gas. The use ratio of the dilution gas is 0.05 to 50 moles, preferably 0.5 to 20 moles per mole of ethanol.

  Next, the present invention will be described in more detail with reference to examples.

Example 1
[Preparation of 10wt% W / H-ZSM5 catalyst]
Tosoh H-ZSM5 (Si / Al2 ratio = 29) 2g impregnated with 0.27g ammonium metatungstate (10wt% in terms of tungsten), dried overnight at 333K, further dried at 373K for 3 hours, then 5 at 873K Air calcination for an hour gave 2.18 g of W / H-ZSM5 catalyst.
[Propylene synthesis reaction]
10% W / H-ZSM5 (0.5 g) thus obtained was introduced into a fixed bed flow reactor, and a mixed gas of ethanol and nitrogen (volume ratio (ethanol / nitrogen = 13.9 / 86.1)) was added at a total pressure of 0.1 MPa. The reaction was carried out at W / F (N ₂ ) = 0.12 mol. (G-cat.h) ⁻¹ , WSV (EtOH) = 0.92 h ⁻¹ , 723K. When the product after the reaction was analyzed by gas chromatography, propylene was produced at an ethanol conversion rate of 98.2% and a propylene selectivity of 24.4% (Table 1). As by-products, ethylene 19.9%, butenes 19.5%, BTX (sum of benzene + toluene + xylene) 20.5% (Table 1), C1 to C10 saturated hydrocarbons and CO2 were detected in small quantities.

For the sake of convenience, the ethanol conversion and propylene selectivity were calculated as follows.
(1) Ethanol conversion = ([EtOH] ⁱ − [EtOH] ^u ) / ([EtOH] ⁱ ) * 100
Here, [EtOH] ⁱ and [EtOH] ^u indicate the initial amount of ethanol introduced and unreacted.
(2) C3 'selectivity = (C3' * 3) / ((Σ (Cn * n): n = 1-10) + C2 '* 2 + C3' * 3 + B * 6 + T * 7 + X * 8 + CO ₂ ) x100
Here, Cn represents a saturated hydrocarbon having n carbon atoms, and C2 ′, C3 ′, B, T, and X represent ethylene, propylene, benzene, toluene, and xylene, respectively. * Represents a product.
Other hydrocarbon selectivity was calculated similarly.

Comparative Example 1
A synthesis reaction of propylene was performed in the same manner as in Example 1 except that H-ZSM5 (Si / Al2 ratio = 29) not modified with tungsten was used as a catalyst. The results are shown in Table 1. The ethanol conversion was 100% and the propylene selectivity was 8.69%, and the propylene selectivity was about 1/3 that of Example 1. In addition, as by-products, C1-C3 saturated hydrocarbons were produced approximately twice at 17.6% and 2.3 times at 46.4% BTX.

Example 2
A propylene synthesis reaction was carried out in the same manner as in Example 1 except that the calcination temperature of the W / H-ZSM5 catalyst was changed to 830 ° C. The results are shown in Table 1. The ethanol conversion rate was 97.1% and propylene selectivity was 17.1%, and the propylene selectivity slightly decreased.

Examples 3-4
A catalyst was prepared and propylene was synthesized in the same manner as in Example 1 except that the Si / Al ₂ ratio of the carrier H-ZSM5 was set to 68 and 190. The results are shown in Table 1. Propylene selectivity was 12.6% and 10.6%, respectively.

Examples 5-6
A catalyst was prepared and propylene was synthesized in the same manner as in Example 1 except that ammonium perrhenate and ammonium molybdate were used in place of ammonium metatungstate instead of 10 wt%. The results are shown in Table 1. In both cases, the ethanol conversion was 99% or more, and the propylene selectivity was 14.8% and 14.0%.

Examples 7-8
A W / H-ZSM5 (29) catalyst was used to carry out a propylene synthesis reaction in the same manner as in Example 1 using a catalyst in which lanthanum nitrate was supported at 1 wt% or 5 wt% based on lanthanum and calcined at 600 ° C for 5 hours. It was. The results are shown in Table 1. The propylene selectivity was 32.1% and 16.5%, respectively. Especially when 1 wt% of lanthanum was supported, an improvement of about 8% in propylene selectivity was observed. In this case, the total of ethylene + propylene + C4 was 94.7%.

Example 9
Using W / H-ZSM5 (29) catalyst, ammonium phosphate aqueous solution, 1wt% of phosphorus supported and calcined at 600 ° C for 5 hours, the synthesis reaction of propylene was carried out in the same manner as in Example 1. I did it. The results are shown in Table 1. The propylene selectivity was 29.5%.

Example 10
W / H-ZSM5 (29) catalyst was loaded with 1% by weight of lanthanum with lanthanum nitrate, calcined at 600 ° C for 5 hours, and further with 1% by weight of phosphorous using an aqueous ammonium phosphate solution, and calcined at 600 ° C for 5 hours. Then, a P / La / W / H-ZSM5 catalyst was prepared.
Using the thus prepared P / La / W / H-ZSM5 catalyst, a synthesis reaction of propylene was carried out in the same manner as in Example 1. The results are shown in Table 1. The propylene selectivity was 30.8%, and the total of ethylene + propylene + C4 was 95.7%.

Example 11
A synthesis reaction of propylene was carried out in the same manner as in Example 7 except that bioethanol (containing 12% water) obtained by fermentation was used instead of ethanol. The results are shown in Table 1. The propylene selectivity was 22.1%.

Example 12
[Catalyst preparation]
Zirconyl nitrate (21 g) is dissolved in distilled water (100 g), and 100 ml of ammonia water diluted with water (ammonia water 25 ml / water 75 ml) is added dropwise to obtain zirconium hydroxide precipitate. After drying at 100 ° C. overnight, it was calcined at 300 ° C. for 3 hours to obtain amorphous zirconia (AZ). Dissolve ammonium sulfate 0.17g in distilled water, put AZ2g in it, evaporate to dryness, let stand at 100 ° C overnight, calcinate at 700 ° C for 5 hours, sulfate zirconia (6wt% SO ₄ / ZrO ₂ ) obtained. The sulfate radical zirconia thus obtained was impregnated and supported with ammonium metatungstate in the same manner as in Example 1, and then calcined at 600 ° C. for 5 hours to obtain 10 wt% W / SO ₄ / ZrO ₂ .
[Propylene synthesis reaction]
A propylene synthesis reaction was carried out in the same manner as in Example 1 using a 10 wt% W / SO ₄ / ZrO ₂ catalyst. The results are shown in Table 1. An ethanol conversion rate of 100% and a propylene selectivity of 9.71% were obtained, and it was found that propylene could be produced by using a support having Bronsted acidity on the surface, instead of a zeolite support.

Claims (5)

  A catalyst for propylene synthesis used for synthesizing propylene by converting ethanol, comprising a porous solid oxide modified with a compound containing a metal belonging to Group 6 and / or Group 7 of the Periodic Table .   A porous solid oxide modified with a compound containing a metal belonging to Group 6 or Group 7 of the Periodic Table is further modified with an element belonging to Group 15 and / or a rare earth of the Periodic Table. Item 4. The catalyst for propylene synthesis according to Item 1.   The catalyst for propylene synthesis according to claim 1 or 2, wherein the porous solid oxide is a zeolite compound.   The catalyst for propylene synthesis according to claim 1 or 2, wherein the porous solid oxide is a sulfate radical-modified metal oxide.   Ethylene is bioethanol obtained by fermentation, The catalyst for propylene synthesis | combination in any one of Claims 1-4 characterized by the above-mentioned.