JPH11228457A - Method for producing cycloolefin - Google Patents

Abstract

(57) [Summary] [PROBLEMS] By pretreating a reactor, efficient
Provided is a method for producing a cycloolefin by partially hydrogenating a monocyclic aromatic hydrocarbon. SOLUTION: A monocyclic aromatic hydrocarbon is made of a material containing at least one metal selected from the group consisting of Fe, Ni, Cr, Mo, Zr, and Ti in the presence of a catalyst and water. A method for producing a cycloolefin to be partially hydrogenated in a reactor, wherein the liquid contacting part is brought into contact with an aqueous solution of a zinc compound in advance, and then the reaction is carried out.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a corresponding cycloolefin by partially hydrogenating a monocyclic aromatic hydrocarbon, and more particularly to a method for producing a cyclohexene by partially hydrogenating benzene. Cycloolefins are compounds useful as important raw materials for polyamides, such as lactams and dicarboxylic acids, and for lysine, drugs, agricultural chemicals, and the like.

[0002]

2. Description of the Related Art Cycloolefin production methods include:
Conventionally, many methods such as partial hydrogenation of monocyclic aromatic hydrocarbons, dehydration of cycloalkanol, dehydrogenation of cycloalkane, and oxidative dehydrogenation have been known.
In particular, a method for obtaining a cycloolefin by partial hydrogenation of a monocyclic aromatic hydrocarbon can be the most simplified reaction step, and is expected to be a preferable method in the process.

As a method for producing a cycloolefin by partial hydrogenation of a monocyclic aromatic hydrocarbon, a method is generally used in which ruthenium metal is mainly used as a catalyst and a hydrogenation reaction is carried out in the presence of water. As a ruthenium catalyst, a method in which metal ruthenium fine particles are used as they are (JP-A-61
-50930, JP-A-62-45541, JP-A-62-
45544) and a method using a catalyst in which ruthenium is supported on a carrier such as silica, alumina, barium sulfate, and zirconium silicate (JP-A-53-63350, JP-A-57-130926, and JP-A-61-129926). 40226, JP-A-4-74141, etc.). In general, in the above reaction, the higher the reaction activity of the catalyst, the lower the selectivity of the obtained cycloolefin tends to be. Therefore, in such a reaction system, a metal salt such as zinc sulfate is present to reduce the reaction activity. A method of suppressing the selectivity and the yield of the corresponding cycloolefin while keeping it low is considered to be preferable. Furthermore, when a metal salt is present in the reaction system, a general-purpose material such as stainless steel causes a problem such as corrosion. Therefore, generally a material having a high corrosion resistance and an expensive material is required as a material of a liquid contact part. . For example, Japanese Patent Publication No. 6-39399 discloses that Ti or Zr is used for a liquid contact part of a reactor.
Proposes to use Mo or a Ni-based alloy w containing Mo and Cr.

[0004]

DISCLOSURE OF THE INVENTION The present inventors have studied this reaction in detail in order to further improve the process for producing cycloolefins by partial hydrogenation of monocyclic aromatic hydrocarbons. It has been found that there is a relationship between the reactor and the reaction performance, and that the reaction performance is affected particularly when a new reactor is used. The present invention has been made based on such findings, and has as its object to provide a method for industrially and advantageously producing a cycloolefin by treating a reactor.

[0005]

Means for Solving the Problems The present inventors have studied to solve the above-mentioned problems, and as a result, by applying a simple pretreatment to the reactor, even when a new reactor is used, the catalyst can be used. It has been found that performance can be sufficiently exhibited and a predetermined reaction result can be obtained, and the present invention has been achieved.

That is, the gist of the present invention is to provide a method in which a monocyclic aromatic hydrocarbon is treated with Fe, Ni, Cr,
In a method for producing a cycloolefin to be partially hydrogenated in a reactor made of a material containing at least one metal selected from the group consisting of Mo, Zr, and Ti, the liquid-contacting part is brought into contact with an aqueous liquid of a zinc compound in advance. After that, the reaction is carried out.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. Examples of the monocyclic aromatic hydrocarbon as a reaction raw material used in the method of the present invention include benzene, toluene, xylene, and lower alkyl group-substituted benzenes having about 1 to 4 carbon atoms. The reaction system of the present invention requires the presence of water. In the presence of water, an organic liquid phase (oil phase) containing a raw material and a product as main components and a liquid phase containing water (aqueous phase) form two phases without stirring. When the ratio between the oil phase and the aqueous phase is extreme, it is difficult to form two phases, and liquid separation is difficult. Further, if the amount of water is too small or too large, the effect of the presence of water is undesirably reduced. The amount of water varies depending on the type of reaction and the like. For example, when the starting material is benzene, it is generally 0.01 to 10 times, preferably 0.1 to 5 times the weight of benzene. Further, in the present invention, a metal salt compound may be contained in water. Examples of the metal salt compound include Group I metals such as Na, Group II metals such as Mg, and sulfates, chlorides, acetates, and phosphates of metals such as zinc, manganese, and cobalt. The amount of the metal salt used is usually 1 × with respect to the water of the reaction system.
It is 10 ^-5 times by weight to 1 times by weight, preferably 1 × 10 ^-4 times by weight to 0.1 times by weight.

[0008] As the catalyst, it is preferable to use a Group VIII element such as Ru and Rh, and particularly preferable is a ruthenium catalyst. Examples of the raw material of ruthenium as a catalytically active component include ruthenium halides, nitrates, hydroxides, complex compounds such as ruthenium carbonyl and ruthenium ammine complexes, and ruthenium alkoxides.
Among them, ruthenium chloride is preferably used. Ruthenium, which is the active component of the catalyst, can be used alone, but other metal components may be used in combination as co-catalyst components. By adding a co-catalyst, the effects of the present invention can be further exhibited. As the co-catalyst component, zinc, iron, cobalt, manganese, gold, lanthanum, copper and the like are effective, and zinc is particularly preferable. As a raw material of the co-catalyst component, a halide, a nitrate, an acetate, a sulfate and a complex compound containing each metal are used. When a co-catalyst metal is used, the atomic ratio of the co-catalyst metal to ruthenium atoms is usually from 0.01 to 20, preferably from 0.1 to 10.
It is.

The ruthenium catalyst can be used either on or off the carrier. The unsupported catalyst precursor may be prepared as a solid by a common coprecipitation method such as an alkali precipitation method using a mixed solution of ruthenium and a compound of a desired promoter metal component. Alternatively, the product may be evaporated to dryness in the form of a homogeneous solution.

[0010] A non-supported catalyst can be used as the ruthenium catalyst. In general, a catalyst supported on a carrier is more preferable because the activity per catalyst component or the stability of the catalyst activity can be easily obtained. As a method for preparing the carrier-supported catalyst precursor, that is, a method for supporting the catalyst component on the carrier, the carrier component is immersed in the catalyst component-containing liquid, and then the solvent is evaporated while stirring to fix the catalyst component, and the evaporation-drying method A known impregnation-supporting method such as a spray method of spraying the catalyst component-containing liquid while keeping the carrier in a dry state, or a method of immersing the carrier in the catalyst component-containing solution and then filtering the carrier is preferably used. As the solvent used for the active ingredient-containing liquid at the time of preparing the catalyst, water or an organic solvent such as alcohol, acetone, tetrahydrofuran, hexane, and toluene is used.
The supported amount of ruthenium is usually 0.001 to 10% by weight,
Preferably it is 0.1 to 5% by weight. Further, the co-catalyst component may be supported at the same time as the ruthenium compound, or may be pre-supported with the ruthenium compound after pre-supporting the co-catalyst component, or may be pre-supported with ruthenium, The components may be carried on the substrate.

[0011] As the carrier used in the above-mentioned carrier-supported catalyst, hardly soluble oxides, composite oxides, activated carbon, metal salts and the like which are generally used as catalyst carriers are used. Specifically, metal salts such as barium sulfate and calcium sulfate, silica, alumina, zirconia, titania, chromina, oxides of rare earth metals, or composite oxides such as silica-alumina, silica-zirconia, zirconium silicate, and zeolite And silica and activated carbon modified with a metal oxide such as zirconia.

Further, among the above carriers, carriers having the following properties can be suitably used. When the pore volume and pore distribution were measured by the mercury intrusion method, the pore diameter was 75 to 100,00.
The total pore volume at 0 ° is 0.2 to 10 ml / g, preferably 0.3 to 5 ml / g, and the pore diameter is 75 to 1
For a total pore volume of 00,000 °, a pore volume with a pore diameter of usually 250 ° or more is 50% or more, preferably 7%.
It is a carrier having pores of 0% or more. 250 pore diameter
If the ratio of the pores smaller than Å is too large, the selectivity tends to decrease, which is not preferable.

Of the above carriers, an oxide carrier is usually preferred, and examples thereof include silica or a carrier obtained by modifying a silica carrier with a transition metal compound, particularly a carrier obtained by modifying zirconia to silica. In this zirconia-modified silica carrier, the amount of zirconia to modify the silica matrix is usually 0.1 to 20% by weight, preferably 0.5 to 10% by weight, based on silica. As a method for preparing a silica carrier modified with zirconia, usually, a solution obtained by dissolving a zirconium compound in water or an organic solvent, or a solution obtained by dissolving a zirconium compound and partially or entirely hydrolyzing with an alkali or the like is used. A method in which a known impregnation supporting method or a dip coating method is suitably used to support the silica, followed by drying and firing is used. Examples of the zirconium compound used here include zirconium halides, oxyhalides, nitrates, oxynitrates, hydroxides, complex compounds such as zirconium acetylacetonate complexes, and zirconium alkoxides. The firing temperature here may be any temperature that is higher than the temperature at which the used zirconium compound is converted to zirconia, and is usually 600 ° C. or higher, particularly 80 ° C.
0-1200 ° C is preferred. However, calcination at a higher temperature exceeding 1200 ° C. is not preferable because crystallization of silica is remarkable and catalyst activity is reduced.

As a method for activating the catalyst precursor, a catalytic reduction method using hydrogen gas or a chemical reduction method using formalin, sodium borohydride, hydrazine or the like is used. Of these, catalytic reduction is preferably performed using hydrogen gas, and is usually performed at 80 to 500 ° C. under a hydrogen-containing gas atmosphere.
Preferably, it is calcined under the condition of 100 to 450 ° C. to activate by reduction. If the reduction temperature is lower than 80 ° C., the reduction ratio of ruthenium is remarkably reduced, and if it is higher than 500 ° C., aggregation of ruthenium is liable to occur, which causes a reduction in the yield and selectivity of cycloolefin formation.

After the above-mentioned reduction treatment, the catalyst can be used as it is in the reaction. Alternatively, such a catalyst can be used after being brought into contact with water or water containing a metal salt. Examples of the metal salt compound include Group 1 metals, Group 2 metals, and sulfates, chlorides, acetates, phosphates, and the like of metals such as zinc, manganese, and cobalt. The amount of the metal salt to be used is generally 1 × 10 ^-5 to 1 times, preferably 1 × 10 ^-4 to 0.1 times by weight of water in the reaction system.

As the conditions for the partial hydrogenation reaction, the reaction temperature is usually 50 to 250 ° C., preferably 100 to 220 ° C.
Is selected from the range. If the temperature is higher than 250 ° C., the selectivity of cycloolefin decreases, and if the temperature is lower than 50 ° C., the reaction rate is remarkably reduced, which is not preferable. The pressure of hydrogen during the reaction is usually 0.1 to 20 MPa, preferably 0.5 to 1 MPa.
It is selected from the range of 0 MPa. If it exceeds 20 MPa, it is industrially disadvantageous. On the other hand, if it is less than 0.1 MPa, the reaction rate is remarkably reduced, which is uneconomical in terms of equipment. The reaction type may be a batch type using one or two or more reactors, or may be a continuous type, and is not particularly limited. However, industrially, a continuous method is preferable.

The material used for the liquid contact part of the reactor used in the present reaction contains at least one metal selected from the group consisting of Fe, Ni, Cr, Mo, Zr and Ti. Specifically, iron-based alloys exemplified by austenitic stainless steels, and alloys exemplified by carpenters, inconel, etc., which have increased nickel content and improved corrosion resistance compared to such alloys , Nickel-based alloys such as Hastelloy-based materials and nickel-copper alloys, and titanium, titanium alloys, and the like. It is preferable to appropriately select the material of the reactor depending on the type and concentration of the salt to be present in the reaction system. When a high concentration of a metal salt is present in the reaction system in order to enhance the selectivity of cycloolefin, a Hastelloy-based material or a titanium alloy is preferable.

The present invention is characterized in that the liquid contact part of the reactor is brought into contact with an aqueous liquid containing a zinc compound. The liquid contact part of the reactor means not only the liquid contact part of the reactor main body but also all the substances which are installed in the reactor and come into contact with the reaction liquid. Examples of the zinc compound contained in the aqueous liquid include sulfates, chlorides, acetates, phosphates, and hydroxides. Among them, zinc sulfate is preferred. The concentration of the zinc compound in the aqueous liquid is usually 0.001 to 100% by weight based on water, preferably
It is 0.01 to 50% by weight. The amount of the aqueous solution containing the zinc compound may be any amount as long as the wetted portion of the reactor is sufficiently wetted. The contact conditions are as follows: the temperature is from room temperature to 300
° C, preferably 50 ° C to 250 ° C. The pressure is from normal pressure to 20 MPa, preferably from normal pressure to 10 MPa. The atmosphere is not particularly limited, but is preferably under a pressurized condition of nitrogen or hydrogen. The contact time is usually from 30 minutes to 1000 hours. Preferably, it is 1 hour to 100 hours. Even if the contact time is too long, the effect does not increase for the time. It is preferable to extract part or all of the water containing the zinc compound used in the present treatment after the treatment and supply the water used for the reaction. The aqueous zinc compound liquid of the present invention may contain benzene and the like in addition to the zinc compound and water.

The treatment with the aqueous zinc compound solution of the present invention comprises:
Effective when using a reactor whose wetted part is made of the above-mentioned material for the first time in this reaction, and also when first using a reactor that has been repaired or surface-treated for the first time. It is a target. The reason why this pretreatment can avoid a decrease in the reaction performance that has conventionally occurred can be avoided, but it is presumed as follows, although it is not always clear. On the surface of the reactor containing the specific metal, there are fine particles, sensitive portions, and other foreign substances of the material of the reactor. These contain components that adversely affect the partial hydrogenation reaction and cannot be completely removed by ordinary washing or the like. It is considered that the pretreatment of the present invention removes such metals and foreign substances and stabilizes the form so as not to affect the reaction. Furthermore, it is conceivable that a trace amount of the zinc compound remains on the reactor surface, and the inside of the reactor may change to a stable state in the present partial hydrogenation reaction.

[0020]

EXAMPLES Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist of the present invention. In addition, the manufacturing method of the catalyst used in the following Examples was as follows. Catalyst manufacturing method

(Manufacture of carrier) Zirconium oxynitrate 2
Silica (trade name: CARIA, manufactured by Fuji Silysia Chemical Ltd.) was added to an aqueous solution in which 0.87 g of hydrate was dissolved in 20 ml of pure water.
(CT50) 8.0 g was added, and after immersion at room temperature, water was distilled off and dried. Next, at 1000 ° C under air circulation,
After calcination for 5 hours, a silica carrier modified with 5% by weight of zirconia based on silica was prepared.

(Preparation of Catalyst Precursor) The above-mentioned zirconia-modified silica carrier is added to an aqueous solution containing a predetermined amount of ruthenium chloride and zinc chloride, immersed at 60 ° C. for 1 hour, water is distilled off, and dried. As a result, a catalyst precursor in which a ruthenium (Ru) component and a zinc (Zn) component were each supported by 0.5% by weight based on the carrier was obtained. (Reduction treatment) The above catalyst precursor was heated at 200 ° C. in a hydrogen stream.
For 3 hours to obtain a ruthenium catalyst.

Comparative Example 1 (Batch Reaction Test without Pretreatment of Reactor) After thoroughly washing with benzene, acetone and water, and drying, a new 500 ml titanium autoclave having an internal volume of the catalyst 3 0.75 g, 150 ml of a 0.1% by weight aqueous solution of cobalt sulfate, and 100 ml of benzene were charged. At a reaction temperature of 150 ° C. and a pressure of 5.0 MPa,
Hydrogen gas is supplied at a flow rate of 57 Nl / Hr, and 1000 r
The mixture was stirred at pm to perform a partial hydrogenation reaction of benzene. The reaction solution was appropriately extracted from a nozzle installed in the reactor, and analyzed by gas chromatography. Table 1 shows the reaction results.
It was shown to.

Example 1 (Zinc sulfate treatment of reactor) After extracting the contents of the reactor used in Comparative Example 1, the inside was sufficiently washed with acetone and pure water, and dried. In this reactor, 24 g of zinc sulfate heptahydrate was added to 200 g of water.
Was dissolved therein. Temperature 200 ° C, pressure 5.
Under a condition of 0 MPa, hydrogen gas was supplied at a flow rate of 57 NL / Hr, stirred at 600 rpm, and zinc sulfate treatment was performed on the inner wall of the reactor for 5 hours. After the reactor was brought to normal temperature and normal pressure, the contents were extracted, and the inside of the reactor was sufficiently washed with pure water. Using this reactor, the partial hydrogenation reaction of benzene was carried out again under the above reaction conditions. Table 1 shows the reaction results.
It was shown to. The reaction rate was improved compared to the first reaction.

Example 2 (Re-treatment with zinc sulfate) The above-mentioned reactor was treated again with zinc sulfate. Further, the benzene partial hydrogenation reaction was performed again by the above method. The reaction results are shown in Table 1.

[0026]

Table 1 Table 1 Reaction time Benzene conversion Cyclohexene Selectivity ─────────────────────────────────── Comparative Example 1 (no pretreatment) 30 minutes 37.4% 59.9% Example 1 (1 time treatment with zinc sulfate) 30 47.6% 54.5% Example 2 (2 times treatment with zinc sulfate) 30 52. 4% 52.4%

Example 3 Into a 1 L reactor having a stationary tank inside and a wetted material made of titanium, and 528 g of water, 192 g of zinc sulfate heptahydrate 192
An aqueous solution in which g was dissolved was charged. Stirring was performed at 600 rpm under the conditions of a temperature of 200 ° C. and a pressure of 4.9 MPa.
The inside wall of the reactor was treated with zinc sulfate for 2 hours. After the reactor was brought to normal temperature and normal pressure, the contents were extracted, and the inside of the reactor was sufficiently washed with pure water. An aqueous solution obtained by dissolving 0.414 g of cobalt sulfate heptahydrate in 230 g of water and 14.3 g of a ruthenium catalyst were charged into the reactor. At a temperature of 150 ° C. and a pressure of 4.9 MPa, stirring was performed at 800 rpm.
250 NL / hr of hydrogen gas and 800 m of benzene
By feeding at a flow rate of 1 / Hr, a continuous reaction of partial hydrogenation of benzene was carried out. Oil-water separation was performed in a stationary tank installed in the reactor, and only the oil phase was continuously taken out of the reactor. The reaction results 2.5 hours after the start of the reaction were as follows: benzene conversion = 4
5.9%. The cyclohexene selectivity was 63.5%.

[0028]

As is clear from the examples, the method of the present invention can be used only when the reactor is used for the first time for this reaction, or after repair of the liquid contact part of the reactor or surface treatment is performed. When used in the present reaction, a decrease in the reaction results can be prevented beforehand, which is industrially very useful.

Claims (3)

[Claims] 1. A monocyclic aromatic hydrocarbon is produced from a material containing at least one metal selected from the group consisting of Fe, Ni, Cr, Mo, Zr and Ti in the presence of a catalyst and water. A method for producing a cycloolefin, which is partially hydrogenated in a reactor, comprising: bringing the liquid contact portion into contact with an aqueous solution of a zinc compound in advance, followed by carrying out the reaction. 2. The process for producing a cycloolefin according to claim 1, wherein the partial hydrogenation reaction is carried out in the presence of a metal salt compound. 3. The method for producing a cycloolefin according to claim 1, wherein the zinc compound is zinc sulfate.