JPS6317834A - Production of cycloolefin - Google Patents

Abstract

PURPOSE:To obtain the titled compound, by adding zirconium oxide or halfnium oxide to a main catalyst of metallic Ru having a specific average crystallite diameter and partially reducing a monocyclic aromatic hydrocarbon in the coexistence of solid basic zinc sulfate under neutral or acidic condition. CONSTITUTION:A monocyclic aromatic hydrocarbon is partially reduced with hydrogen in the coexistence of water to give a cycloolefin. In the process, hydrogenation catalyst particles, containing metallic ruthenium (particularly a reduced ruthenium prepared by previously containing zinc) as a principal component and having <=200Angstrom , particularly <=100Angstrom average crystallite diameter are used and at least one of zirconium oxide or halfnium oxide (preferably having 0.005-100mu average particle diameter) is added separately from the above- mention catalyst particles. The reaction is carried out in the coexistence of at least one solid basic zinc sulfate under neutral or acidic condition. EFFECT:Cyclohexenes are particularly obtained in high selectivity and yield.

Description

[Detailed description of the invention] (Industrial application field) The present invention partially reduces monocyclic aromatic hydrocarbons.

The present invention relates to a method for producing corresponding cycloolefins, especially cyclohexene, with high selectivity and high yield.

Cyclohexenes have high value as intermediate raw materials for organic chemical industrial products, especially polyamide raw materials.

It is important as a raw material for lysine.

(Conventional technology) 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 Ⅰ of the periodic table (Japanese Patent Publication W356-2
2850 Publication), +21 A method in which an oxidized ruthenium catalyst is supported on oxides of nickel, cobalt, chromium, and titanium and zirconium is used, and an ester is used as an additive in the alcohol solution (% Publication No. 52-5955).
, +31 species, a method of conveniently using a ruthenium catalyst containing silver, cobalt, or potassium and a phosphate compound (% Publication No. 56-4556); , iA group metals, and manganese.

Neutral 19 containing a salt of at least one cation selected from
-7607 Publication), (51) A solid catalyst containing at least one of ruthenium and rhodium as a main component is
Using an aqueous solution containing a salt of at least one cation selected from the group consisting of Group A metals, [A''55 metals, iron, and zinc, in the presence of water:
How to do so (%Kaisei No. 51-98245), (
6) A method in which a ruthenium catalyst is used and at least one of zinc oxide and zinc hydroxide is added to the reaction system as an activating component to react (Tokukoku No. 8 An 59-184138).

(7) In the presence of carbon and at least one zinc compound
, a method using aggregated particles of metal ruthenium crystallites having an average crystallite diameter of less than or equal to zooX has been proposed (Japanese Patent Application Laid-Open No. 61-50930).

(Problem to be solved by the invention) However, in these conventionally known methods.

Selection book for target cyclohexene? To my friend,
Currently, the yield and productivity of cyclohexenes are generally low because it is necessary to significantly suppress the conversion rate of raw materials, the reaction rate is extremely low, and there is no practical method for producing cyclohexenes.

In addition, in order for such a method for producing cyclohexene to be practical, it is necessary and important that the catalyst used in one reaction can continuously maintain stable activity or selectivity for 1 g.

In the conventional technology, it cannot necessarily be said that it is a light component in this respect.

Also, according to the inventors' study, an example is JP-A #M3
When the metallic ruthenium particles proposed in Publication No. 61-50950 are used alone as a catalyst, cycloolefins may be obtained in relatively high yields, but only one reactor and the part in contact with the reaction liquid are used. 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 to or accumulates on the substrate, or the catalyst itself changes.

(Means for solving problems) The present inventors aimed to solve such problems.

In order to improve the yield of cyclohexenes and obtain a stable catalyst system that is advantageous in terms of production, we have developed a catalyst system for the partial reduction of monocyclic aromatic raw carbon and arsenic, that is, a system consisting of a main catalyst and other components. The present invention has been arrived at through intensive study.

That is, 1. the present invention uses hydrogenation catalyst particles mainly composed of metal ruthenium having an average crystallite diameter of 200λ or less when partially reducing monocyclic aromatic hydrocarbons with hydrogen in the presence of water; Separately from the particles, at least one of zirconium oxide or non-funium oxide is added, and further, reaction [5] is carried out under neutral or acidic conditions in the coexistence of at least one solid basic zinc sulfate. , we obtained cycloolefins with unprecedented properties.

Moreover, it is a method for producing cycloolefins that can be used as surprisingly stable catalyst systems. According to the method of the present invention, it will be possible to increase the yield of cycloolefins to 40% or more. This is an extremely useful method from a practical point of view, as it can clearly suppress changes in reaction results due to regression of the reduction, changes in the Hei 7J crystallite diameter, and the like.

One specific embodiment of the present invention will be described below.

What is the monocyclic aromatic hydrocarbon that is the raw material of the present invention?

Refers to benzene, toluene, xylenes, and lower alkylbenzenes having an alkyl group having 4 or less carbon atoms.

In the present invention, hydrogenation catalyst particles containing ruthenium as a main fraction having an average crystallite diameter of 2001 or less are present all around. The catalyst can be obtained by reducing one of the various ruthenium compounds, or may be prepared during its preparation or after preparation by using other gold compounds, e.g.

Zinc or chromium, molybdenum, tungsten.

The main component is ruthenium, cobalt, nickel, iron, and steel. There are no particular restrictions on the ruthenium compound used by woodcutter.

For example, chlorides, bromides, iodides, nitrates, sulfates,
Hydroxide, cyclized product, ruthenium red, or various complexes containing ruthenium can be used. Reduction methods include reduction with hydrogen gas, formalin, and sodium borohydride.

This can be carried out by a chemical reduction method using hydrazine or the like. In particular, ruthenium salts are hydrolyzed to form hydroxides,
A method of reducing this is preferably used.

In the method of the present invention, a reduced product of ruthenium containing zinc in advance is used.

The yield of cycloolefins can be further increased and used effectively. Such a catalyst is a reduced product obtained by previously impregnating a valuable ruthenium compound with a zinc compound and then reducing it, in which ruthenium is reduced to a metallic state and becomes a metal. Examples of valuable ruthenium compounds that can be used include salts such as chlorides, nitrates, and sulfates, complexes such as ammine complexes, hydroxides, and rR compounds.
Particularly preferred are pentavalent or tetravalent ruthenium compounds because they are readily available and easy to handle. A wide range of zinc 16 compounds can be used, including chlorides, nitrates, sulfates, complexes such as ammine complexes, hydroxides, and oxides.

The zinc content in such catalysts is 0.1 to ruthenium.
-50 weight difference, preferably 2-20 weight difference. Once upon a time, the main components of a catalyst were:

It is just 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 ruthenium reduction method t'' can be applied.For example, a method of reducing with hydrogen in a gas phase, a method of reducing with hydrogen or an appropriate ruthenium in a liquid phase, etc. Chemical reducing agent 1 For example, a method of reducing using gold such as NaBH4 or formalin is preferably applied, and a method of reducing using hydrogen in a gas phase or liquid phase is particularly preferable.

When reducing with hydrogen in the gas phase, the increase in crystallite diameter t
- To avoid this, it is recommended to take measures such as diluting hydrogen with other inert gases or diluting hydrogen with other inert gases to avoid extremely high temperatures.

When reducing in the liquid phase, add water or alcohol to
It may be carried out by dispersing a solid of a valuable ruthenium compound containing zinc, or it may be carried out in the form of a homogeneous solution6.

At this time, -& stir to make the continuous firing progress better.

It is advisable to heat it appropriately. Further, instead of water, an alkaline aqueous solution or an appropriate metal salt water mQ1, such as an alkali metal salt aqueous 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 in order to increase the selection of cycloolefins, the yield, and the reaction rate. , the average crystallite diameter of the crystallites must be 200X or less, and 1soX
It is preferably below, and more preferably 1ooX or below. Here, the average crystallite diameter is determined by the general method,
That is, it is calculated from the expansion of the diffraction width obtained by the X-ray diffraction method using the formula of 5cherrer. Specifically, in the case of 7 using CuKCl rays as an X-ray source, it is calculated from the spread of a diffraction line having a Ki large around 44° at one diffraction angle (2θ).

In the present invention V, the reaction is carried out by adding at least one zirconium oxide or hyhafnium oxide in addition to the hydrogenation catalyst particles as described above.

The fireflies of the oxides that are present in the reaction system have I
X 10-3 to 0.3 times by weight, preferably 1 x 10-
2 to 0.1 times the weight.

The oxide to be added is preferably in the form of powder, with an average particle size d of 0.005 to 100 μm, more preferably 0.005 to 10 μm. The average particle size is determined by using ethanol as a dispersion medium, adding 1% by weight or less of an oxide to the dispersion medium, and dispersing it in an ultrasonic oscillation tank of several hundred watts for 30 to 60 minutes. This is a value calculated by measuring the absorption yt and L change fhi of a dispersion liquid in a sedimentation method (natural sedimentation method, centrifugation tX, groaning method).

The effects obtained by adding such m (aluminium) are very useful; one is that it can improve the selectivity of cycloolefins and the collection rate of cycloolefins;
By suppressing fluctuations in the reaction system caused by adhesion of the hydrogenation catalyst to the reactor surface and agglomeration of the hydrogen ratio catalyst, and maintaining a stable reaction system, continuous It is highly effective in producing cycloolefins. In addition, the slurry containing the hydrogenation catalyst can be easily handled, for example, the hydrogen ratio catalyst can be diluted or increased in volume, and the catalyst preparation and recovery can be facilitated.

On the other hand, what should be specified is that the immersion method,
Ruthenium is supported by a conventional method such as a drying method or a precipitation method, prepared by reduction, and a ruthenium-supported catalyst is used as a hydrogen ratio catalyst. The addition of oxides in the process of the invention is essentially different from that of supported ruthenium catalysts.

In the present invention, at least 1a of solid basic zinc sulfate is further allowed to coexist in the reaction system. Here, solid basic zinc sulfate is ZnSO4-mZno ・nH,0
Or ZnSO4-mZn(OH)l (where m, n
each represents a number of 0.5 times m≦4.0≦n≦8).

Furthermore, “tz+1) (OH)tt-8O4(
Here, t represents the integer a of 1≦t≦4), and specifically, ZnS
O4・±ZnO*Zn5O,-ZnO-H,0(ZnS
O4・Zn (OH)t) or Zn@ (OH)!
S04 tZnSO, -3ZnO, Zn5O, -5Zn
Osu 3H10 (ZnSO4-3Zn(OR), ).

Zn5O, -3ZnO-6H,0, Zn5O, -5Zn
O-7H,Os Zn5O,”5ZnO-8H,0,Z
n5O,-4ZnO-4H,0(ZnSO,-42n(
OH) Ridoga Roshi, authored works (e.g. Complete Book of Inorganic Chemistry, [
-Page 11500, circle @) is also a group of compounds that are often found.

These basic zinc sulfates have been known for a long time.

It can be obtained by various methods, but generally it can be obtained by using an aqueous zinc sulfate solution as a mother liquor, reacting it with a suitable alkali and heating it at 7'C. Ma7t, 4J[CI! It can also be obtained as a mixture of various basic zinc sulfates by adding zinc hydroxide to an aqueous solution of 12 or an aqueous zinc sulfate solution and heating the mixture.

In order to coexist these solid basic zinc sulfates in the reaction system,
It is preferable to mix one type or a mixture of these with the hydrogenation catalyst and oxide in powder form, or to add them separately to the reaction system. Mayu, as described below, when an aqueous zinc sulfate solution is used in the reaction, in the reaction system, a compound 1, part or all of which changes into solid basic zinc sulfate, such as zinc hydroxide or zinc oxide, is reacted. May be added to the system.

Generally, the solubility of basic zinc sulfate in water is low;
When added in a small amount, it can coexist as a solid in the reaction system. Furthermore, when the hydrogenation catalyst of the present invention is used, due to the adsorption power of the hydrogenation catalyst, even if the amount added is below the saturation solubility of basic zinc sulfate in the reaction system, Furthermore, it can coexist as a solid on oxides.

In the present invention, such solid basic zinc sulfate is allowed to coexist with the hydrogenation catalyst in an amount of 4 to 1 times by weight as zinc, preferably 3 to 0.5 times by weight as zinc. If the coexisting amount is too small, the effect on improving cycloolefin selection and yield will be weak, and if it is too large, the reaction rate will decrease.

As a result, a large amount of hydrogen catalyst is required, which is not an industrially advantageous system.

In this way, rI! By coexisting with J-isomer basic zinc sulfate, the selection and yield of cycloolefins can be increased. Moreover, the equivalent high selectivity straw.

A high yield rate can be maintained, the reaction temperature range has been expanded, and cycloolefins can be obtained at relatively low temperatures, increasing the degree of freedom in selecting reaction conditions, making it extremely valuable industrially. Become.

In addition, it is not necessarily clear why the coexistence of basic zinc sulfate improves the selection and yield of cycloolefins, but the coexisting insoluble basic zinc sulfate is 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 an oxide and the coexistence of solid basic zinc in the present invention have a surprising effect on the stability of the catalyst as described below.

In general, the use of fine metal catalysts means that the metal is supported on a carrier, and unlike secondary catalysts, secondary agglomeration and sintering often progress, resulting in a stable catalyst system. There is a problem with sexuality. This also applies to the metal ruthenium catalyst used in the method of the present invention.
In terms of practicality, avoiding the progression of secondary agglomeration and sintering is an absolutely necessary technology.

It has been revealed that the coexistence of solid basic zinc sulfate, which is a disadvantage of the present invention, also has the effect of suppressing changes in the catalyst due to such secondary aggregation and sintering. Addition of zirconium or hydrafnium oxides also has similar effects, and these oxides and solid basic zinc gF
The synergistic effect of rivers can make catalysts and reaction systems extremely stable.

In the absence of solid basic Vt acid zinc and df,
When the water-Xf-hybrid catalyst used in the present invention is maintained under anti-46 conditions, secondary aggregation of the catalyst proceeds more rapidly.

In this way, [a catalyst in which secondary aggregation has further progressed].

The dispersibility of catalyst particles in the aqueous phase becomes significantly poor.

In aggregates with 7 in this state, it becomes difficult for hydrogen to diffuse into the metal ruthenium in the aggregate and for benzene to diffuse, especially hydrogen, and sufficient t necessary for one reaction is supplied onto the catalyst. Therefore, 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.

The diffusion of the cycloolefin produced by the Mayu 1 reaction out of the warped field or out of the pre-agglomerated body is slow, and the hydrogenation reaction progresses further, increasing the number of reactions to form cycloalkanes. do. 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 held under reaction conditions for a long time in the absence of solid basic zinc sulfate and oxide, the average crystallite of metallic ruthenium determined by X-ray diffraction It can be seen that the diameter increases. Such an increase in the average crystallite size over time results in a decrease in the surface area of the catalyst, and in particular, the reaction rate decreases over time, making it difficult to control a stable reaction over a long period of time. This tendency shows that when the concentration of the hydrogenation catalyst and the reaction temperature are increased, the head fK becomes even more.
This makes it more difficult to maintain the stability of the reaction, which is not preferred in practice.

It is clear that it is desirable that such catalyst changes be as small as possible. Zr used in the present invention
It has been found that only by using O or Hf in combination with basic zinc sulfate can a situation be achieved in which the above-mentioned increase in the average crystallite diameter of 14-ruthenium over time can be practically ignored9.

The mechanism by which the stability ratio of the warpable yarn according to the present invention increases is not necessarily clear, but solid basic zinc sulfate is present on the surface of the hydrogenation catalyst or oxide and changes the properties of the surface. ZRO, HfO
The coexistence of , greatly suppresses collisions between hydrogenation catalysts, and 1
It is thought that secondary aggregation of the catalyst, which is an indirect cause of a decrease in surface area and an increase in crystallite size, is further suppressed.

As mentioned above, the extremely high 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. The amount of water varies depending on the type of warping, but it can be made to coexist with 0.01 to 100 times the weight of the commonly used monocyclic aromatic hydrocarbon. ! , it is necessary to form two phases, an organic liquid phase mainly composed of substances and a liquid phase containing water, and the coexistence of a very small amount of water that becomes a homogeneous phase under the reaction conditions, or a very small amount of water. The presence of too much water will reduce the effectiveness, and too much water will require a larger reactor.

Practically speaking, it is desirable that O and S coexist by ~20 times the weight.

In the present invention, a more preferable selectivity and yield of cycloolefin can be obtained by using an aqueous solution of a metal salt instead of water as in the conventionally known method. Examples of metal salts include Kaede, Group IA of the periodic table, and I
Group IA metals, ■B metals, manganese (for example,
7-7607), nitrates, salts, and sulfates of cobalt.

Acetate, phosphate, etc. are used, but group IA metals, n
Salts of Group A metals and zinc are preferred, and more preferably strong acid salts such as chlorides and sulfates.

Furthermore, in the case of Kb of the present invention, preferable results can be obtained by using an aqueous solution of a strong acid salt of zinc, especially zinc Kffl acid, in place of water. Basic sulfur Cl in zinc sulfate aqueous solution!
When zinc coexists, a solubility equilibrium is established between ions and compounds, and although the zinc sulfate aqueous solution is acidic, only a trace amount of basic zinc sulfate dissolves in the aqueous solution, leaving a state in which basic zinc sulfate is completely insoluble. It can be kept stably in the system. -Example t-To name 1, for example, 10
% aqueous solution (pH approximately 5), ZnSO4-3Zn(OH
If you add more than a few tens of pounds to the incoming water, the pH of the liquid will be 5.7~
Stable at around 5.8, Zn5O4e 3Zn(OH)
* is an insoluble one! Can exist in water. Matsugi,
The coexistence of basic zinc sulfate in a zinc sulfate aqueous solution means that
As in the above example, it also has the effect of bringing the pH of the aqueous solution closer to neutral).

It is thought that it will also have a considerable effect on corrosion of equipment metal materials that occurs due to the acidity of the zinc sulfate aqueous solution.

Such an aqueous zinc sulfate solution can be used with a degree of solubility ranging from 0.01% by weight to saturation solubility, preferably 0.01% by weight.
It is preferable to use it in an amount of 1 to 50% by weight.

In the reaction system of the present invention, insoluble basic zinc sulfate must be present in one reaction solution. Although it varies depending on the amount of the insoluble basic zinc sulfate present and the amount of the aqueous solution, it is preferable that the reaction is carried out in an alkaline to acidic state. 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.

A stationary phase method can also be used. What are the reaction conditions?

Although it is appropriately selected depending on the type and f of the catalyst and additives used, the hydrogen pressure is usually 1 to 2 o kg/dG.

Preferably it is in the range of 10 to 100 kg/ciG.

The reaction temperature is room temperature to 250'C, preferably 100 to 200'C.
It is in the 0Co range. The reaction time may be appropriately selected by determining the actual target value of the selectivity and yield of the desired cyclohexene, and is usually from several seconds to several hours, although there is no particular limitation.

(Effects of the Invention) According to the present invention, cycloolefins can be obtained with unprecedentedly high selectivity and yield.

It becomes a stable catalyst system and 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 Ru(OH)s t'' Friendly metal ruthenium catalyst (average crystallite diameter 50X) obtained by reduction with pressurized hydrogen in water
, s t %zro, powder (average particle size 0,35 tt
) 2.5? , 30 mg of the basic zinc sulfate shown in Table 1 as zinc.

and 280 m of a 18% aqueous solution of ZnSO4-7H,O
'k.

Prepared in an autoclave with an internal volume of 1 ton of titanium.

After purging with hydrogen and heating to 150C with stirring, benzene 1
40d was introduced under pressure, and the reaction was carried out under high speed stirring at a total pressure of 50% and 9/cdc. This reaction solution was extracted over time, and the composition of the oil phase was analyzed by gas chromatography. The results are shown in Table 1&'C. The regular creature is b two friends with Cyclo and middle school.

In addition, after the reaction was completed, one reactor was released and carefully inspected.
The catalyst particles and ZrO powder were well dispersed, no agglomeration was observed, and there was almost no adhesion of the catalyst to the titanium wall.

Table 1 Example 4 Instead of ZrO powder, HfO2 powder (average particle size 1.
The reaction was carried out in the same manner as in Example 1, except for using 0.05μ). The results are shown in Table 2.

Table 2 Comparative Example 1 Zr0. 9. The same procedure as in Example 1 was carried out except that the powder and basic Vt acid zinc were not used. The results are shown in Table 5.

Table 5 After the completion of Mayu 1 reaction, 1 reactor was opened and observed.
Catalyst agglomeration was observed, and catalyst adhesion occurred on the titanium wall.

Comparative Example 2 The same operation as in Example 1 was carried out except that ZrO and powder were not used. The results are shown in Table 4.

Table 4 In addition, after one reaction was completed, one reactor was opened and observed, and then,
However, almost no agglomeration of the catalyst was observed.

Adhesion of catalyst was observed on the titanium wall surface.

Comparative Example 3.4 A conventional impregnating method (by adsorbing and impregnating ZrO, H and HfO, K ruthenium chloride, followed by hydrogen reduction, supporting 1% by weight of the friend metal ruthenium, and producing a nine-bond hydrogenation catalyst 5.
The same operation as in Example 1 was performed except that Zr02 was used and Zr01 was not added. The results are shown in Table S.

Table 5 ↓ It is clear that the yarn to which ZrO, HfO, i is added in the present invention is completely different from the usual supported catalyst system.

Example 5 The reaction temperature was set to 120C and the same operation as in Example 1 was carried out except for the following. The results are shown in Table 6.

Table 6 Comparative Example 5 The same operation as in Example 5 was performed except that basic zinc sulfate was not used. The results are shown in Table 7.

Table 7 Example 6 Reduction product of ruthenium containing toughened zinc as a catalyst (zinc content: 7.01%, average crystallite diameter: 48^)
Using o and sy, Tomo et al. performed the same operations as in Example 1. The results are shown in Table 8.

'14 Example 7 10(
The results are shown in Table 9.IQ was used, water was used as glue 9 for an 18% aqueous solution of Zn5O,.7H30, and all other operations were carried out in the same manner as in Example 3.

Table 9 After completing the reaction in Example 7, the slurry was filtered.

After recovery, concentrated hydrochloric acid was added to the catalyst and ZrO, and the 9! When one compound was dissolved in , and the zinc and sulfur in this solution were determined by plasma detection spectroscopy, it was 95η for zinc and 18η for 6th order. This clearly shows the coexistence of solid basic zinc sulfate.

Comparative Example 6 Catalyst used iii O.05t, ZrO! Example 7 except that powder and basic vL cough zinc were not used.
Table 10 shows the results of nine experiments performed in the same manner as above.

Table 10 Example 8 Same catalyst as Example 1 (average crystallite diameter 50A) 1j f
, ZrO, powder (average particle size 0.35μ) 7,57
゜Zn5O, -3Zn (OH), k as 0.
69% processed ZnSO4・7H, 018% aqueous solution 150
d'i, coated with niteflon on the inner surface, placed in an autoclave with an internal volume of fc of 400, and heated to a total pressure of 1so with hydrogen.
kg/dG and held at 160C for 200 hours with high speed stirring. After collecting the slurry and cleaning it for 1 hour, the average crystallite diameter of the catalyst metal ruthenium was determined by X-ray diffraction method. When measured, there was almost no change in the 1 reaction rate when 53A was used, and when the reaction rate was changed to 53A.

Comparative Example 7 ZrO, powder and ZnSO4.4 Zn(OH)t
When Tomo et al. performed the same operation as in Example 8 without using K, the average g & particle size of the recovered catalyst metal ruthenium increased significantly to 78λ, and the change over time of the M medium was clear. .

In addition, when the reaction was carried out using 1/3 of the recovered material and adjusting the liquid composition such as additives so that the conditions were the same as in Example 1, the warping speed decreased to about 1/2. .

Comparative Example 8 When Tomo et al. carried out the same operation as in Example 8 without using powdered ZrO, the average crystallite diameter of the catalyst metal ruthenium was 61A and 9.

When the reaction was carried out using the recovered material 115 under the same conditions as in Example 1 by adjusting the liquid composition such as the nitrate, the reaction rate was reduced to about 3/4.

It is clear from Example 8 and Comparative Examples 7 and 8 that the catalyst system used in the process of the present invention is extremely stable.

Claims (7)

[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, production of a cycloolefin characterized by adding at least one of zirconium oxide or hafnium oxide and further carrying out the reaction under neutral or acidic conditions in the coexistence of at least one solid basic zinc sulfate. Method. (2) The method for producing a cycloolefin according to claim 1, wherein the hydrogenation catalyst is a reduced product of ruthenium containing zinc in advance. (3) The 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 oxide added is 1 x 10^-^3 relative to water
The method for producing a cycloolefin according to claim 1, wherein the amount is 0.3 times by weight. (5) The average particle diameter of the oxide to be added is 0.005 to 10
The method for producing a cycloolefin according to claim 1, wherein the cycloolefin has a particle diameter of 0μ. (6) The method for producing a cycloolefin according to claim 1, wherein the amount of coexisting solid basic zinc sulfate is 1 x 10^-^4 to 1 times the weight of zinc relative to the hydrogenation catalyst. (7) A method for producing a cycloolefin according to claim 1, wherein the reaction is carried out in the presence of an aqueous zinc sulfate solution.