JP2003080071A - Catalyst for selectively oxidizing hydrogen and method for dehydrogenating hydrocarbon using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a catalyst useful for selectively oxidizing hydrogen in a gas containing hydrogen formed by the dehydrogenation reaction of hydrocarbons, hydrocarbons being the raw material and produced unsaturated hydrocarbons. SOLUTION: The solid catalyst contains an element selected from the group of copper and silver of group 11 of the periodic table as an active component and an element selected from the group of antimony and bismuth of group 15 of the periodic table, and is substantially free from elements of the platinum group.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a non-platinum group catalyst for selectively catalytically oxidizing hydrogen in a gas containing hydrogen and hydrocarbons with oxygen. The present invention also relates to a method of bringing a gas containing hydrocarbon, hydrogen and oxygen into contact with this catalyst to selectively oxidize hydrogen in the gas.

[0002]

It is known to contact hydrocarbons in gaseous form with a dehydrogenation catalyst to produce hydrocarbons having olefinically unsaturated bonds. For example, the main production method of styrene is a method of dehydrogenating ethylbenzene in a gaseous state by contacting it with an iron-based dehydrogenation catalyst. However, since this dehydrogenation reaction is an endothermic reaction, the temperature of the gas decreases as the reaction progresses. Further, since the dehydrogenation reaction is an equilibrium reaction, hydrogen produced as a by-product hinders the progress of the reaction. For these reasons, it is difficult to carry out the dehydrogenation reaction of ethylbenzene to styrene at a high reaction rate.

As a method for avoiding this difficulty, a gas containing styrene, hydrogen and unreacted ethylbenzene produced by the dehydrogenation reaction is mixed with an oxygen-containing gas and brought into contact with an oxidation catalyst to selectively hydrogen the gas. After oxidation, it is considered to contact with a dehydrogenation catalyst again. According to this method, the temperature of the reaction product is raised by the selective oxidation of hydrogen, and hydrogen that inhibits the progress of the reaction is removed, so that the subsequent dehydrogenation reaction can be advantageously progressed.

[0004]

As a catalyst for selectively oxidizing hydrogen in a gas produced by a dehydrogenation reaction, it is generally said that a catalyst containing a platinum group element as an active component is preferable. Many catalysts have been proposed to include.
However, since the platinum group element is small in production and extremely expensive, there is a demand for a catalyst that does not contain the platinum group element and has the same performance as that containing the platinum group element.
The present invention seeks to meet such demands.

[0005]

According to the present invention, an element selected from the group consisting of copper and silver of Group 11 of the Periodic Table of Elements as an active ingredient, and the group consisting of antimony and bismuth of Group 15 of the periodic table. The hydrogen coexisting with the hydrocarbon is selected by bringing the catalyst containing the element selected from the above and containing substantially no platinum group element into contact with the gas containing the hydrocarbon, hydrogen and oxygen. Can be oxidised.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The hydrogen selective oxidation catalyst according to the present invention contains elements of Groups 11 and 15 of the Periodic Table as active components. Copper or silver is used as the Group 11 element, and copper is particularly preferably used. If desired, copper and silver can be used together. Antimony or bismuth is used as the Group 15 element, but bismuth is preferably used. If the Group 15 element is desired, antimony and bismuth may be used in combination.

In addition to these active ingredients, the catalyst may be used in combination with a heat-resistant inorganic carrier in order to optimize the catalytic activity and improve the catalyst strength. As the heat-resistant inorganic carrier, alumina, silica, titania, niobium oxide, tantalum oxide and the like are preferably used, but heat-resistant inorganic carriers other than these, such as germanium oxide, tin oxide and gallium oxide, can also be used. If desired, some heat resistant inorganic carriers may be used in combination. As the alumina, γ-alumina or α-alumina is used, but especially α
-Preference is given to using alumina. Silica and titania may be crystalline or amorphous. As niobium oxide, niobium pentoxide is preferably used. Most preferred as the heat-resistant inorganic carrier is α-alumina or niobium pentoxide.

The catalyst contains a Group 11 element, which is an active ingredient, in an amount of 0.
It is preferable to contain 001 to 10% by weight, particularly 0.05 to 5% by weight. When the content of the Group 11 element is low, the catalytic performance tends to be low. On the contrary, even if the content of the Group 11 element exceeds 10% by weight and becomes high, the catalyst performance is hardly affected. The form of the Group 11 element existing in the catalyst is unknown, but it is considered that it exists as a monovalent or divalent oxide. It is also considered that a part of them is zero-valent, that is, it exists as a metal.

The content of the Group 15 element in the catalyst is preferably 0.1% by weight or more. The Group 15 element is considered to exist in a trivalent to pentavalent state, but it is preferable that antimony exists as a tetravalent or pentavalent oxide and bismuth exists as a pentavalent oxide. Conceivable. The catalyst can be prepared by a conventional method. For example, a compound of a Group 15 element is fired to form an oxide, which is then
The catalyst can be prepared by impregnating with a solution containing an inorganic acid salt or an organic acid salt of a Group 1 element, followed by drying and firing. In the case of a catalyst with a carrier, the heat-resistant inorganic carrier is impregnated with a solution containing a compound of Group 15 element and dried.
A catalyst can be prepared by calcining, and then impregnating a solution containing a compound of the Group 11 element with the solution and drying and calcining. The order of loading the Group 15 element and the Group 11 element on the carrier is arbitrary, and the loading operation may be alternately performed a plurality of times, or both may be loaded simultaneously. If desired, the Group 11 element may be supported and then treated with hydrogen or another reducing agent.

The selective oxidation reaction of hydrogen using the catalyst according to the present invention is usually carried out at 300 to 800 ° C. When the temperature is lower than this, the selectivity does not change so much, but the activity decreases. On the contrary, if the temperature is too high, the activity is improved but the selectivity is decreased. The preferred reaction temperature is 400-700 ° C. The reaction pressure is from reduced pressure to slightly increased pressure, especially from 0.0049 to
0.98 MPa is preferable. The ratio of oxygen to hydrogen in the gas used for the reaction is preferably a stoichiometric amount or less. In this case, although coking may occur on the catalyst when the oxygen is completely consumed, it does not hinder the selective oxidation reaction of hydrogen.

In a typical process for the selective oxidation of hydrogen using a catalyst according to the present invention, first of all, a first dehydrogenation reactor filled with a dehydrogenation catalyst is mixed with a hydrocarbon as a raw material, preferably as a mixture with steam. Supply at high temperature to cause dehydrogenation reaction. The reaction product gas flowing out from the dehydrogenation reactor is mixed with an oxygen-containing gas such as air and supplied to an oxidation reactor filled with the catalyst according to the present invention to selectively oxidize hydrogen and to generate gas temperature by reaction heat. Raise. The reaction product gas flowing out from the oxidation reactor is then supplied to a second dehydrogenation reactor filled with a dehydrogenation catalyst to dehydrogenate the remaining raw material hydrocarbons. The reaction product gas flowing out from the second dehydrogenation reactor is further mixed with an oxygen-containing gas and then sequentially passed through the second oxidation reactor and the third dehydrogenation reactor to further increase the reaction rate of the raw material hydrocarbons. It can also be improved. As the raw material hydrocarbon to be subjected to the dehydrogenation reaction, any one that can form a carbon-carbon double bond by dehydrogenation can be used, but ethylbenzene, diethylbenzene,
Like ethylnaphthalene, diethylnaphthalene, etc.,
It is preferred to use aromatic compounds having dehydrogenatable hydrocarbon substituents. Particularly preferred is ethylbenzene, a dehydrogenation reactor filled with a conventional iron-based dehydrogenation catalyst, and a Group 11 element and a Group 15 element as active ingredients according to the present invention.
Styrene is obtained in high yield from ethylbenzene by performing a dehydrogenation reaction in 2 to 5 stages in combination with an oxidation reactor containing a group-group element and substantially not containing a platinum-group element. Can be manufactured.

[0012]

EXAMPLES The present invention will be described in more detail with reference to the following examples. Example 1 Preparation of catalyst: 0.04 g of copper nitrate as copper and 0.04 g of bismuth nitrate as bismuth were dissolved in 8 g of 35% nitric acid aqueous solution to prepare a solution containing copper and bismuth. This solution was put into a rotary evaporator, and spherical α-alumina having a diameter of 3 mm was added thereto.
The mixture was kept at 60 ° C. under reduced pressure for 1 hour to evaporate water, and copper and bismuth were supported on α-alumina. This α-alumina was placed in a drier and dried at 120 ° C. for 3 hours, and then calcined in the air at 650 ° C. for 3 hours to obtain Cu-Bi / α-Al.
_{A 2} O ₃ catalyst was prepared.

Reaction: In a quartz reaction tube having an inner diameter of 6.7 mm,
A quartz chip having a particle size substantially the same as that of the catalyst was filled, 2 ml of the catalyst prepared above was filled therein, and the above quartz chip was further filled therein. A hydrogen-nitrogen mixed gas containing 10% hydrogen was passed through the reaction tube at 600 ° C. for 30 minutes to reduce the catalyst. Next, ethylbenzene, styrene, steam, hydrogen, oxygen and nitrogen were added to the reaction tube at 1: 0.
A raw material gas containing 4: 11.5: 0.43: 0.18: 0.69 (molar ratio) was added under normal pressure at 580 ° C. and SV = 65.
Hydrogen was selectively oxidized by passing at 50 hr ⁻¹ (0 ° C., 1 atm conversion). The reaction tube outflow gas was cooled by a cooler to condense the condensable components. Two hours after the start of the reaction, the reaction tube outlet gas and the condensate of the receiver were analyzed by gas chromatography. As a result, the oxygen conversion rate was 100% and the hydrogen conversion rate was 4%.
0.9%, styrene and ethylbenzene combustion rate 1.2%
Met. The styrene and ethylbenzene burning rate is the percentage of the total number of moles of styrene and ethylbenzene lost in the reaction with respect to the total number of moles of styrene and ethylbenzene supplied to the reaction tube.

Comparative Example 1 8 g of an aqueous solution containing 0.04 g of copper nitrate as copper was placed in a rotary evaporator, and spherical α-alumina having a diameter of 3 mm was added thereto. The mixture was kept under reduced pressure at 60 ° C. for 1 hour to evaporate water, and copper was supported on α-alumina.
This α-alumina was placed in a drier and dried at 120 ° C. for 3 hours, and then calcined in the air at 650 ° C. for 3 hours to obtain Cu /
An α-Al ₂ O ₃ catalyst was prepared. The hydrogen oxidation reaction was carried out in the same manner as in Example 1 except that this catalyst was used. Two hours after the start of the reaction, the reaction tube outlet gas and the condensate of the receiver were analyzed by gas chromatography. As a result, the oxygen conversion rate was 100%, the hydrogen conversion rate was 10.5%, and the styrene and ethylbenzene combustion rate was 1.5%.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Totsuru Iwakura             1 Toho-cho, Yokkaichi-shi, Mie Mitsubishi Chemical Corporation             Ceremony company Yokkaichi office F-term (reference) 4G069 AA02 AA03 BA01A BA01B                       BB02A BB02B BC24A BC25A                       BC25B BC26A BC30A BC31A                       BC31B BC32A CB07 CB18                       CD10 EA02Y EB18Y FC08                 4H006 AA02 AC12 BA05 BA13 BA19                       BD20 BD60                 4H039 CA21 CC10

Claims (9)

[Claims] 1. A periodic table of elements of No. 11 as an active ingredient.
Characterized by containing an element selected from the group consisting of copper and silver of Group 15 and an element selected from the group consisting of antimony and bismuth of Group 15 and containing substantially no platinum group element A catalyst for selectively catalytically oxidizing hydrogen in a gas containing hydrogen and hydrocarbon with oxygen. 2. The catalyst according to claim 1, wherein the proportion of the element selected from the group consisting of copper and silver of Group 11 in the whole catalyst is 0.001 to 10% by weight. 3. The proportion of an element selected from the group consisting of Group 15 antimony and bismuth in the whole catalyst is
The catalyst according to claim 1 or 2, wherein the content is 0.1% by weight or more. 4. The catalyst according to claim 1, which contains copper and bismuth as active components. 5. The catalyst according to claim 1, which contains a heat-resistant inorganic carrier. 6. The catalyst according to claim 1 is contacted with a gas containing hydrocarbon, hydrogen and oxygen to selectively oxidize hydrogen in the gas. Method for selective oxidation of hydrogen coexisting with hydrocarbon. 7. The method for selective oxidation of hydrogen according to claim 6, wherein a gas containing hydrocarbon, hydrogen and oxygen is brought into contact with the catalyst at 300 to 800 ° C. 8. A first dehydrogenation step of contacting a gas containing a raw material hydrocarbon with a dehydrogenation catalyst to produce a gas containing an unreacted raw material hydrocarbon, dehydrogenated hydrocarbon and hydrogen, a first dehydrogenation step. An oxygen-containing gas is mixed with the gas flowing out of the process, and then the catalyst is brought into contact with the catalyst according to claim 1 to selectively oxidize hydrogen in the gas. 3 of the second dehydrogenation step of dehydrogenating the raw material hydrocarbons in the gas in contact with the dehydrogenation catalyst
A hydrocarbon dehydrogenation method comprising at least a step. 9. A first dehydrogenation step of bringing a gas containing ethylbenzene into contact with a dehydrogenation catalyst to produce a gas containing ethylbenzene, styrene and hydrogen, and mixing the oxygen-containing gas with the gas flowing out from the first dehydrogenation step. Then, the oxidation step of contacting the catalyst according to any one of claims 1 to 5 to selectively oxidize hydrogen in the gas, and the gas discharged from the oxidation step is contacted with a dehydrogenation catalyst to remove ethylbenzene in the gas. A method for producing styrene by dehydrogenation of ethylbenzene, comprising at least three steps of a second dehydrogenation step of dehydrogenating to styrene.