JPS6388139A - Production of cycloolefin - Google Patents

Abstract

PURPOSE:To obtain the titled compound useful as a raw material for polyamide, etc., in high yield, by partially reducing a monocyclic aromatic hydrocarbon in the presence of water and a solid basic zinc salt using a highly active specific catalyst system composed of a main catalyst and other components and stable over a long period. CONSTITUTION:The objective compound can be produced by partially reducing a monocyclic aromatic hydrocarbon with hydrogen under neutral or acidic condition in the presence of at least one kind of a solid basic zinc salt (prefer ably basic zinc sulfate) and water, using a catalyst system comprising (A) a hydrogenated catalyst particle composed mainly of metallic ruthenium having an average crystal particle diameter of <=200Angstrom , preferably <=100Angstrom or a reduc tion product of ruthenium doped with zinc and (B) hydrate of hydroxide or oxide of one or more metals selected from Ti, Zr, Hf, Nb, Ta, Cr, etc., (prefer ably Zr hydroxide).

Description

Detailed Description of the Invention (Industrial Application Field) The present invention provides a method for partially reducing monocyclic aromatic hydrocarbons to produce corresponding cycloolefins, particularly cyclohexanes, with high selectivity and high yield. It is related to.

Cyclohexenes have great value as intermediate raw materials for organic chemical industrial products, and are particularly important as raw materials for polyamides, lysine, etc.

(Prior art) As a method for producing such cyclohexanes, for example,
(1) A method using a catalyst composition containing water, an alkaline agent, and an element of group Vm of the periodic table (Japanese Patent Publication No. 56-ZZSSO
(2) A method using a ruthenium catalyst supported on an oxide of nickel, conort, chromium, titanium or zirconium and using alcohol or varnish as an additive (Japanese Patent Publication No. 3933/1982), (3
) A method using a ruthenium catalyst containing copper, complex, near /SA/to, ma'fcl'i potassium, water and a phosphate compound (Japanese Patent Publication No. 4536/1983), +
4) Ruthenium catalyst and group IA metals of the periodic table, II
At least one selected from AIA group metals and manganese
A method of reacting in the presence of a neutral or acidic aqueous solution containing a salt of a cation of a species (Japanese Patent Publication No. 57-7607), <5
) A solid catalyst containing at least one of ruthenium and rhodium as a main component in an aqueous solution containing a salt of at least one cation selected from the group consisting of Group IA metals of the Periodic Table, Group IIAIA metals, iron, and zinc. A method of reacting in the presence of water using a pretreated product (Japanese Patent Application Laid-Open No. 1983-9
(6) A method of reacting using a ruthenium catalyst and adding at least one of zinc oxide and zinc hydroxide as an activating component to the reaction system (Japanese Patent Application Laid-open No. 59-18
4138), (7) A method using metal ruthenium crystallites and/or aggregated particles thereof having an average crystallite diameter of 200λ or less in the presence of water and at least one zinc compound (Japanese Patent Laid-Open No. 61 -50930), etc. have been proposed.

(Problems to be Solved by the Invention) However, in these conventionally known methods, in order to increase the selectivity of the target cyclohexene, it is necessary to significantly suppress the conversion rate of the raw material, or the reaction rate is slow. The yield and productivity of cyclohexenes are generally low, such as very small sizes, and currently there is no practical method for producing cyclohexenes.

In addition, in order for the method for producing cyclohexene to be practical, it is necessary and important that the catalyst used in the reaction can continuously maintain stable activity or selectivity. Conventional techniques are not necessarily sufficient in this respect.

Furthermore, according to the studies of the present inventors, for example, JP-A-61
When the metallic ruthenium particles proposed in Publication No. 50930 are used alone as a catalyst, cycloolefins may be obtained in relatively high yields, but It has been found that there are many cases in which it is difficult to maintain a stable reaction system, such as when the catalyst adheres or accumulates, or when the catalyst itself changes.

(Means for Solving the Problems) In order to solve the problems, the present inventors aimed to improve the yield of cyclohexene and to obtain a stable catalyst system that is industrially advantageous. The present invention was arrived at after intensive study on a catalyst system in a hydrogen partial reduction method, that is, a system consisting of a main catalyst and other components.

That is, the present invention uses hydrogenation catalyst particles containing metal ruthenium as a main component and having an average crystallite size of 200X or less when partially reducing a single aromatic hydrocarbon with hydrogen in the presence of water. Apart from Ti, Zr,
Hf, Nb, Ta, Cr, Fe, Co.

Adding a hydrate of at least one metal hydroxide or oxide selected from Aβ, Ga, St, and
By carrying out the reaction under neutral or acidic conditions in the coexistence of at least one solid basic zinc salt, cycloolefins can be produced in unprecedentedly good yields, and moreover, it can be used as a surprisingly stable catalyst system. This is a method for producing cycloolefins.

According to the method of the present invention, the yield of cycloolefins can be increased to 40%.
% or more, and at the same time, the combination of the present invention can prevent various deterioration of the hydrogenation catalyst, such as progression of agglomeration over time, change in average crystallite diameter, etc. This is an extremely useful method from a practical standpoint, as it can significantly suppress changes.

Below, specific implementation of the present invention,! ! ? Explain the situation.

The monoary aromatic hydrocarbons used as raw materials for the present invention include benzene, toluene, xylenes, and carbon Ix4 or less.

Refers to lower alkylbenzenes having an alkyl group.

In the present invention, hydrogenation catalyst particles containing metallic ruthenium as a main component and having an average crystallite diameter of 200X or less are used. These catalysts can be obtained by reducing various ruthenium compounds or, during or after their preparation, contain other metals, such as zinc or chromium, molybdenum, tungsten, manganese, coronate, nickel,
'? The main component is ruthenium to which f14 is added. There are no particular restrictions on the various ruthenium compounds, but examples include chlorides, bromides, iodides, nitrates,
Sulfate, hydroxide, oxide, ruthenium red, or various complexes containing ruthenium can be used. Reduction methods include reduction with hydrogen gas or chemical reduction with formalin, sodium borohydride, hydrazine, etc. This can be done by In particular, a method of hydrolyzing a ruthenium salt to form a hydroxide and reducing this is preferably used.

Furthermore, in the method of the present invention, if a reduced product of ruthenium containing zinc in advance is used, the yield of cycloolefin can be further increased, and it is effectively used. Such a catalyst is a reduced product obtained by previously impregnating a valuable ruthenium compound with a zinc compound and then reducing the resulting ruthenium compound, in which ruthenium is reduced to a metallic state. Valuable ruthenium compounds that can be used include, for example:
These include salts such as chlorides, nitrates, and sulfates, complexes such as ammine complexes, hydroxides, and oxides, but trivalent or tetravalent ruthenium compounds are particularly easy to obtain, and
It is preferred because it is easy to handle. Furthermore, a wide range of zinc compounds can be used, including salts such as chlorides, nitrates, and sulfates, complexes such as ammine complexes, hydroxides, and oxides.

The zinc content in such catalysts is 0.1 to ruthenium.
The content is adjusted to 50% by weight, preferably 2 to 20% by weight. Therefore, the main component of the catalyst is ruthenium, and zinc is not a carrier.

Valuable ruthenium compounds containing such zinc are
It may be obtained as a solid by a general coprecipitation method using a mixed solution of zinc and ruthenium compounds, or it may be obtained as a homogeneous solution.

As a method for reducing such a valuable ruthenium compound containing zinc, a general method for reducing ruthenium can be applied. For example, a method of reducing with hydrogen in the gas phase, a method of reducing with hydrogen or an appropriate chemical reducing agent such as NaBH4 or formalin in the liquid phase, and a method of reducing with hydrogen in the gas or liquid phase are preferably applied. is particularly preferred.

When reducing with hydrogen in the gas phase, it is recommended to avoid extremely high temperatures or to dilute water with another inert gas in order to avoid an increase in crystallite size. Further, when the reduction is carried out in a liquid phase, it may be carried out by dispersing a solid valuable ruthenium compound containing zinc in water or alcohol, or it may be carried out in the state of a homogeneous solution. At this time, in order to facilitate the reduction,
It is advisable to carry out appropriate stirring, heating, etc. Furthermore, instead of water, an aqueous alkaline solution or an appropriate aqueous metal salt solution, such as an aqueous alkali metal salt solution, may be used.

The hydrogenation catalyst particles described above exist in the reaction system mainly as crystallites made of ruthenium and/or aggregated particles thereof, but the selectivity and yield of cycloolefins, as well as K, are important for increasing the reaction rate. The average crystallite diameter of the crystallites must be 200^ or less, preferably 150λ or less, and more preferably xooX or less.

Here, the average crystallite diameter is determined by a general method, that is, from the spread of the diffraction line width n obtained by the X-ray diffraction method.
It is calculated using the rrerO formula.

Specifically, when CuKa rays are used as an X-ray source,
It is calculated from the spread of a diffraction line that has a maximum around 440 degrees at a diffraction angle (2θ).

In the present invention, in addition to the above hydrogenation catalyst particles, Tt, Zr, Hf, Nb, Ta, Cr,
Fe.

The reaction is carried out by adding a hydroxide or hydrate of an oxide of at least one metal selected from Co, Aλ, Ga, and St, and hydroxides of zr and Hf are preferred, and further, Hydroxide of zr is preferred.

The amount of the metal hydroxide or oxide hydrate to be added is I x 1 in terms of the amount of the metal alone relative to water.
0-4 to 0.3 times by weight, preferably I x 10-3 to
Hydrates of such metal hydroxides or oxides, which may have a weight of o, i, are generally obtained by hydrolysis of an aqueous salt solution of the metal or by addition of an alkali, ammonia, or the like. A wide variety of metal salts can be used, such as chlorides, bromides, iodides, oxychlorides, nitrates, sulfates, and complexes containing the metals.

The effect obtained by adding such a hydroxide or oxide hydrate is to suppress fluctuations in the reaction system due to adhesion of the hydrogenation catalyst to the reactor surface or agglomeration of the hydrogenation catalyst, and to stabilize the reaction system. Maintaining the reaction system is particularly effective when producing cycloolefin continuously over a long period of time. Still, there is an effect of making it easier to handle the slurry containing the hydrogenation catalyst, for example, by apparently diluting the hydrogenation catalyst, increasing the cap, and making it easier to charge and recover the catalyst.

On the other hand, what should be specified is that a ruthenium-supported catalyst prepared by supporting ruthenium on a hydroxide or oxide hydrate by a conventional method such as a dipping method, a drying method, a precipitation method, etc. When used as a hydrogenation catalyst, the selectivity of cycloolefins is extremely low compared to the method of the present invention, and the addition of oxides in the method of the present invention is essentially different from the ruthenium supported catalyst. be.

In the present invention, the solid basic zinc salt coexisting in the reaction system refers to a zinc salt that combines a conjugate base residue of various acids with a hydroxyl group or an oxygen atom that is considered to be a dusty component. Specifically, for example, Z n S 04・1/2 Z n
O, Zn 804 ” ZnO・N20. Zn S
O4・! 3ZnO-nH20 (n is 0 (n≦8)
, basic zinc sulfate such as ZnSO4・4Zn0・4H20, ZnF2・4Zn(OH)2,
Zn0・3ZnCj! 2 'H20, ZnO"ZnC
f12”N20 and 1.5H3o.

3Zn0 ・2ZnCA2 ・11H20,2ZnO−
ZnCft2 ・11H20゜2ZnO-Z nCA1
2 ・4H20, 5Zn0 ・2ZnC12・26H2
0,5Zn0 ・5ZnCI12 ・8H20,3Zn
O・ZnCf2・nN20 (n is 2.3° 4.5. 8), 4ZnO-ZnCn2-nN20 (n is 4.6
or 11), 5ZnO-ZncJ! 2 ・nN20(
n is 6.8 or 29).

11Zn02ZnC12,6ZnO・ZnCA2・6
H20 and 10H20°8ZnO'ZnCJ! 2 ・
10H20,9ZnO-ZnCf2 ・3H20 and 14H20,ZnRr21ZnC1nH20 (n is 10
．． 13 or 29).

ZnBr2 ・5Zn()6H20,ZnBr2 ・6
Zn0 ・35H20, ZnI2'4Zn(OH)2.
Zn5・5Zn0・11H20, ZnI2・9ZnC1
Basic zinc halides such as 24H, O, etc.
ZnO-N205 ・4H20,4ZnO-N205・
4H20,5ZnO・N205-5 H, O and 6
N20.5 Z n O-N205 ・Basic zinc nitrate represented by 5H*O, 4Zn□PzOs・N20
There are basic zinc orthophosphates represented by , and basic zinc acetate. In particular, basic zinc sulfate and basic zinc chloride give good results.

Any basic zinc salt can generally be obtained by appropriately treating an aqueous solution of the zinc salt. For example, it can be obtained as a solid by using an aqueous solution of zinc salt as a mother liquor and treating it with a suitable alkaline agent or by heating it. Alternatively, a mixture of various basic zinc salts may be obtained by adding zinc hydroxide or zinc oxide to an aqueous solution of a strong zinc salt and boiling it. It may also be obtained by appropriately treating metallic zinc.

In order for these to coexist as solids in the reaction system, it is preferable to mix these 1s or a mixture with the ruthenium catalyst in powder form and add them separately to the reaction system.

In the method of the present invention, these basic zinc salts must coexist in an insoluble state. The solubility of basic zinc salts in aqueous solutions is generally negligible when the aqueous solution is neutral, but it increases as the pH of the aqueous solution decreases, so the amount added to the reaction system depends on the pH of the aqueous solution. It is preferable to take this into consideration when deciding. However, due to the adsorption power of the Z ruthenium catalyst used in the present invention, it is often possible to coexist as a solid on the catalyst even if the amount added is below the saturation solubility of the basic zinc salt in the reaction system.

Such a solid basic zinc salt can be separated from the reaction system together with the hydrogenation catalyst and directly confirmed as a solid by X-ray diffraction, X-ray fluorescence, X-ray photoelectron spectroscopy, etc. In addition, as a method for quantifying the coexisting amount of this solid basic zinc salt, a method is preferably used in which the solid separated together with the hydrogenation catalyst is dissolved and measured.

Specifically, after the catalyst slurry is precipitated from the reaction solution, the supernatant liquid is removed and an insoluble basic zinc salt is added to the remaining slurry 17 + or to the solid obtained by filtering the slurry in the reaction solution. This can be determined by adding a dissolvable liquid, such as concentrated hydrochloric acid, and then analyzing a certain amount of zinc ion, which is commonly carried out.

In addition, in order to eliminate the influence of ions coexisting in the reaction system on the analysis, in some cases, after washing the slurry or filtered solid with water in which the amount of dissolved basic zinc salt can be ignored. , concentrated hydrochloric acid, etc. may be added to quantify zinc ions.

In the present invention, the solid basic zinc salt is added to the hydrogenation catalyst in an amount of 1 x 10''4 to
The reaction is carried out in the presence of 1 times by weight, preferably from 10-3 to 0.5 times by weight. If the coexisting amount is too small, the effect on improving the selectivity and yield of cycloolefin will be weak, and if it is too large, the reaction rate will decrease, resulting in the need for a large amount of hydrogenation catalyst. It is difficult to create an advantageous reaction system.

By coexisting one solid basic zinc salt in this manner, the selectivity and yield of cycloolefin can be increased. Furthermore, the reaction temperature range in which the same high selectivity and yield can be maintained has been expanded, and cycloolefins can be obtained in good yield even at relatively low temperatures, so the degree of freedom in selecting reaction conditions has expanded, and industrial It becomes extremely valuable.

Although it is not necessarily clear why the selectivity and yield of cycloolefins improve due to the coexistence of basic zinc salts, the coexisting insoluble basic zinc salts are adsorbed onto the hydrogenation catalyst, It is thought that active sites advantageous for the production of cycloolefins are exposed.

On the other hand, the addition of a metal hydroxide or oxide hydrate and the coexistence of solid basic zinc in the present invention exhibit surprising effects on the stability of the catalyst as described below.

Generally, when using a fine metal catalyst, unlike a catalyst in which the metal is supported on a carrier, secondary aggregation and sintering often occur in the reaction system, making it difficult to maintain a stable catalyst system. be. The same holds true for the metal ruthenium catalyst used in the method of the present invention, and from the viewpoint of practicality, it is an absolutely necessary technique to avoid the progression of secondary aggregation and sintering.

Surprisingly, it has been revealed that the coexistence of a solid basic zinc salt in the present invention also has the effect of suppressing changes in the catalyst due to such secondary aggregation and sintering.

Tt, Zr, Hf, Nb, Ta, Cr,
Fe, Co, AJ! .

Addition of hydrates of hydroxides or oxides of metals selected from Qa and St also has similar effects, and the combination of hydrates of hydroxides or oxides of these metals and solid basic zinc salts The synergistic effect can make the catalyst and reaction system extremely stable.

If the hydrogenation catalyst used in the present invention is maintained under reaction conditions in the absence of a solid basic zinc salt and a hydrate of the hydroxide or oxide of the above-mentioned metals, secondary aggregation of the catalyst will further proceed. do.

In a catalyst in which secondary aggregation has further progressed in this way, the dispersibility of catalyst particles in the aqueous phase becomes significantly poor.

In aggregates in this state, it becomes difficult for hydrogen and benzene to diffuse into the metal ruthenium in the aggregate, especially for hydrogen, and it becomes impossible to supply a sufficient amount of hydrogen to the catalyst for the reaction. It is not possible to obtain a satisfactory reaction state. In particular, when the supply of hydrogen onto the catalyst is insufficient, the reaction rate decreases and side reactions increase significantly. In addition, the diffusion of the cycloolefin produced by the reaction to the outside of the reaction field or to the outside of the pre-agglomerated body is slowed down,
Further, the hydrogenation reaction progresses, and side reactions to cycloalkanes increase. Such changes in the aggregation state can also be directly observed using an electron microscope.

Similarly, when the hydrogenation catalyst used in the present invention is kept under reaction conditions for a long time in the absence of a solid basic zinc salt and a hydrate of the hydroxide or oxide of the metal,
Metals determined by line diffraction method.

It was found that the average crystallite diameter of ruthenium increases. Such an increase in the average crystallite size over time results in a decrease in the surface area of the catalyst, and the reaction rate decreases over time by %, making it difficult to control a stable reaction over a long period of time. This tendency becomes even more pronounced when the hydrogenation catalyst is raised to 4°C or the reaction temperature is increased.For example, when attempting to carry out this reaction by increasing the productivity of cycloolefin per reactor volume, the reaction This means that it becomes more difficult to maintain stability, which is not practical. It is clear that it is desirable that such catalyst changes be as small as possible. Only by the combination of the hydroxide or oxide hydrate and the basic zinc salt used in the present invention can a situation in which the above-mentioned increase in the average crystallite size of metal ruthenium over time be substantially ignored. It turned out that.

Furthermore, in the present invention, when Zr and Hf hydroxides are used as the hydroxides and basic zinc sulfate is used as the basic zinc salt, the stabilizing effect on the hydrogenation catalyst as described above is particularly high. It turns out.

Although the mechanism by which the reaction system is stabilized by the present invention is not entirely clear, it is believed that the solid basic zinc salt exists on the surface of the hydrogenation catalyst or oxide, changing the properties of the surface. considered to be a thing. Ti, Zr, H
f, Nb, Ta, Cr, Fe, Co.

A1. The coexistence of at least one hydroxide or hydrate of an oxide selected from Ga and S1 greatly suppresses collisions between hydrogenation catalysts, and prevents indirect collisions that cause a decrease in surface area and an increase in crystallite size. It is thought that this further suppresses secondary aggregation of the catalyst, which can cause problems.

As described above, the extremely stable reaction system achieved for the first time by a combination such as the method of the present invention can be said to be extremely valuable from a practical and industrial standpoint.

The present invention requires the presence of water. Hydrogen can coexist in an amount of 0.01 to 100 times the weight of commonly used monocyclic aromatic hydrocarbons, although this varies depending on the reaction format. The organic liquid phase as a component and the liquid phase containing water are 2
It is necessary to form a phase, and the coexistence of an extremely small amount of water that becomes a homogeneous phase under the reaction conditions, or the coexistence of an extremely large amount of water will reduce the effect, and the amount of water that is too large will reduce the effect. Since it is necessary to increase the size of the reactor, it is practically desirable to coexist 0.5 to 20 times by weight.

Further, in the present invention, by using an aqueous solution of a metal salt instead of water as in a conventionally known method, it is possible to obtain even more preferable selectivity and yield of cycloolefin. Examples of metal salts include Group IA metals of the periodic table, I
Group A metals, Group IIB metals, manganese (for example,
7-7607), nitrates, chlorides, sulfates, acetates, phosphates, etc. are used, but I
Salts of group A metals, I [group A metals and zinc are preferred, and K is preferably a strong acid salt such as a chloride or sulfate.

Furthermore, in the present invention, preferable results can be obtained by using an aqueous solution of a strong acid salt of zinc, particularly zinc sulfate, instead of water.

Such an aqueous zinc sulfate solution can be used at a concentration from 0.01 weight i-% to a saturation solubility, but preferably 0.01 wt.
．． It is preferable to use it in an amount of 1 to 30% by weight.

Furthermore, in the reaction system of the present invention, the reaction must be carried out in a neutral or acidic state in the aqueous solution. If the water and phase are made alkaline, the reaction rate will drop significantly, making it difficult to provide a practical method for producing cycloolefins. Further, to make it acidic, ordinary acids such as hydrochloric acid, nitric acid, sulfuric acid, acetic acid, phosphoric acid, etc. may be added. The pH of the aqueous solution thus introduced into the reaction system is 0.5 to 7 or less, preferably 2 to 6.5.

In the reaction system of the present invention, insoluble basic zinc sulfate must be present in the reaction solution. Therefore, it is preferable that the reaction system be carried out in a slightly alkaline to acidic state, although it varies depending on the amount of the insoluble basic zinc sulfate coexisting and the amount of the aqueous solution. More preferably, it is carried out in a neutral to acidic state.

The partial reduction reaction in the method of the present invention is usually carried out continuously or batchwise by a liquid phase suspension method, but it can also be carried out by a solid phase method. The reaction conditions are appropriately selected depending on the type and amount of the catalyst and additives used, but usually the hydrogen pressure is 1 to 200 Kf10n2G, preferably 10 to
The reaction temperature is in the range of room temperature to 250°C, preferably 100 to 200°C.The reaction time is determined depending on the selectivity and yield of the target cyclohexene. It is sufficient to set a target value and select it as appropriate, and although there is no particular restriction, it is usually several seconds to several hours.

(Effects of the Invention) According to the present invention, cycloolefins can be obtained with unprecedentedly high selectivity and yield, and furthermore, a stable catalyst system is obtained, which is extremely valuable industrially.

(Examples) Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples.

Examples 1 to 3 A caustic soda aqueous solution was added to an aqueous zirconium oxychloride solution, the resulting white solid was filtered, and washing with water and filtration were repeated until no chloride ions were detected in the filtrate to obtain zirconium hydroxide.

This zirconium hydroxide is called ZOg as zirconium.
, Metallic ruthenium catalyst obtained by reducing Ru (OH)3 in water with pressurized hydrogen (average crystallite diameter 5oX)
o, sg, 100% of the basic zinc salt shown in Table 1 as zinc
mg, and 280 d of water were placed in a titanium autoclave with an internal volume of 11, and the atmosphere was replaced with hydrogen while stirring at 150°C.
After raising the temperature to
Retain hydrogen to maintain p/c1t1"G and heat to 150℃
, a hydrogenation reaction was carried out for a predetermined period of time. After the reaction, the organic layer was rapidly cooled and analyzed by gas chromatography. The results are shown in Table 1.
Shown below. The by-product was cyclohexane.

Table 1 In addition, in Examples 1 to 3, after the reaction was completed, the reactor was opened and observed. In all cases, the catalyst and zirconium hydroxide were well dispersed, with no aggregation observed, and the catalyst and zirconium hydroxide were not observed on the titanium wall surface. There was no adhesion.

Comparative example 1 Metal ruthenium catalyst (average crystallite diameter 50X) 0, 05
The reaction was carried out for 30 minutes in the same manner as in Example 1 except that zirconium hydroxide and basic zinc salt were not used. The conversion rate of benzene was sax%, the selectivity of cyclohexene was λ3, and the yield of cyclohexene was 1.5.

In addition, after the reaction was completed, the reactor was opened and observed.
Agglomeration of the catalyst was observed, and catalyst adhesion occurred on the titanium wall surface.

Examples 4 to 13 ZOg using the hydroxide shown in Table 2 as a metal, 0.5 g of a metal ruthenium catalyst (average crystallite diameter soX), 30 mg of Zn5O+・3Zn (OH)2 as a basic zinc salt, and 10 280 ml of zinc sulfate aqueous solution was charged into a titanium autoclave having an internal volume of 12, and reacted for 60 minutes in the same manner as in Example 1. The results are shown in Table 2.

However, in the case of hafnium hydroxide, each hydroxide was prepared from hafnium oxychloride, and in the case of other hydroxides, from chloride by hydrolysis and washing with water.

Margin Table 2 Below Comparative Examples 2 and 3 Add RuCff13 to the hydroxide shown in Table 3 at 1% Ru
Supported hydrogenation catalyst reduced with sodium borohydride as Ru, O, 05g, 10% zinc sulfate aqueous solution 2
80- was charged into a titanium autoclave with an internal volume of 12 and reacted for 30 minutes in the same manner as in Example 1. The results are shown in Table 3.

Table 3 Example 14 Reduction product of ruthenium containing zinc in advance as a catalyst (zinc content 5.6%, average crystallite diameter asX) o,
The same operation as in Example 4 was performed except that sg was used, and 60
Allowed to react for minutes. The conversion rate of benzene was 57.2%,
The selectivity of cyclohexene was 81.8, and the yield of cyclohexene was 46.8%.

Example 15 Same catalyst as Example 1 (average crystallite diameter 50'A) 1.5 g
7.0 g of monohydroxide as metal, ZnSO4・3Z
0.6 g of n (OH)2 as zinc and 150 gt of aqueous solution of zinc 10 sulfate were charged into an autoclave with an internal volume of 400 m1 whose inner surface was coated with Teflon, and the total pressure was adjusted to 50 4/cm2G with hydrogen, and the mixture was heated at 160°C. The mixture was held for 200 hours while stirring at high speed. After collecting and washing the slurry, the average crystallite diameter of the catalytic metal ruthenium was measured by X-ray diffraction, and it was found to be less than ssX, and there was almost no change in any of the hydroxides used.

Next, a reaction was carried out using 1/3 of the recovered slurry to which zircoium hydroxide was added as a hydroxide, adjusting the liquid composition such as additives so that the conditions were the same as in Example 4. There was almost no change in both reaction rate and selectivity.

Comparative Example 4 The same operation as in Example 15 was performed except that hydroxide and ZnSO4.3Zn(OH)z were not used, and the average crystallite diameter of the recovered catalyst metal ruthenium was 91
It was A.

Further, when a reaction was carried out using 1/3 of the recovered material and adjusting the am composition of additives and the like to tJI4 so that the conditions were the same as in Example 4, the reaction rate was reduced to about half of that in Example.

It is clear from Example 15 and Comparative Example 4 that the catalyst system used in the method of the present invention is extremely stable.

Claims (6)

[Claims] (1) When monocyclic aromatic hydrocarbons are partially reduced with hydrogen in the presence of water, hydrogenation catalyst particles containing metal ruthenium as a main component and having an average crystallite diameter of 200 Å or less are used. Separately, Ti, Zr, Hf, Nb, Ta
, Cr, Fe, Co, Al, Ga, Si, and further in the coexistence of at least one solid basic zinc salt. , a method for producing cycloolefins characterized by carrying out the reaction under neutral or acidic conditions. (2) A method for producing a cycloolefin according to claim 1, wherein the hydrogenation catalyst is a reduced product of ruthenium containing zinc in advance. (3) A method for producing a cycloolefin according to claim 2, wherein the zinc content in the hydrogenation catalyst is 0.1 to 50% by weight based on ruthenium, which is the main component. (4) The amount of the metal hydroxide or oxide hydrate to be added is 1 x 1 in terms of the amount of the metal alone relative to water.
A method for producing a cycloolefin according to claim 1, wherein the amount is 0^-^4 to 0.3 times by weight. (5) The cyclocompound according to claim 1, wherein the amount of the coexisting solid basic zinc salt is 1×10^-^4 to 1 times the weight of the hydrogenation catalyst in terms of the amount of zinc alone. How to produce olefins (6) A method for producing a cycloolefin according to claim 1, in which the reaction is carried out in the coexistence of an aqueous zinc sulfate solution.