JPS6144830A - Production of cycloolefin - Google Patents

Abstract

PURPOSE:To improve the selectivity and yield of the titled compound useful as a raw material of polyamide, etc. by the partial reduction of a monocyclic aromatic hydrocarbon in the presence of a catalyst and water, by adding an alcohol and a zinc compound to the reaction system. CONSTITUTION:The objective compound can be produced by the partial reduction of a monocyclic aromatic hydrocarbon with hydrogen in the presence of a hydrogenation catalyst containing ruthenium as a main component, water, and an additive consisting of at least one kind of alcohol and at least one kind of zinc compound as essential components. The reduction is carried out preferably at 100-200 deg.C under hydrogen pressure of 10-100kg/cm<2>G. The alcohol used as a component of the additive is preferably a >=3C primary alcohol, and its amount is 1X10<-4>-0.5pts.wt. per 1pt.wt. of the raw material. The weight ratio of the zinc compound to water is preferably 1X10<-4>-0.1, and that of water to the raw material is preferably 0.5-20.

Description

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

Cyclohexenes have high value as intermediate raw materials in the organic chemical industry, and are particularly important as raw materials for polyamides and lysine.

(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 I of the periodic table (Japanese Patent Publication No. 56-22850), (a powdered ruthenium catalyst and a group IA element of the periodic table,
A method using a neutral or acidic aqueous solution containing a salt of at least one cation selected from the group consisting of HA group metals, manganese, zinc, and ammonia
No. 536), (method using a catalyst containing at least one noble metal of group Ⅰ of the periodic table and at least one of silver and copper (Japanese Patent Application Laid-Open No. 53-63350)
etc. have been proposed.

(Problems to be Solved by the Invention) However, in these conventionally known methods, it is necessary to keep the conversion rate of the raw material extremely low in order to increase the selectivity of the target cyclohexene. At present, the yield of cyclohexene is low and there is no practical method for producing cyclohexene.

(Means for Solving the Problem) In order to solve the problem, the present inventors have developed a catalyst system in a partial reduction method for monocyclic aromatic hydrocarbons in order to improve the selectivity and yield of cyclohexene. That is, the present invention was arrived at after intensive study on a system consisting of a main catalyst and other components.

That is, a hydrogenation catalyst mainly containing ruthenium and water,
They also discovered that by using at least one type of alcohol and at least one type of zinc compound as additives, cyclohexanes can be obtained with unprecedentedly excellent selectivity and yield. According to the method of the present invention, cyclohexanes can be obtained with high selectivity and high yield by appropriately selecting the reaction conditions and the addition rate of monocyclic aromatic hydrocarbon.

Next, specific embodiments of the present invention will be described.

Monocyclic aromatic hydrocarbons used as raw materials in the present invention include benzene, toluene, xylenes, and lower alkylbenzenes.

Hydrogen catalysts are mainly catalysts containing ruthenium,
Ruthenium may be used alone or may contain other metals as a co-catalyst. Cocatalysts that are known per se, such as elements from group Ⅰ of the periodic table, copper, silver, chromium, vanadium,
It refers to gold and the like, and the inclusion of these does not detract from the gist of the present invention. The catalyst does not necessarily require a carrier and can be used in the form of a sponge or particulate, but catalysts such as silica, alumina, silica-alumina, natural and synthetic zeolites, zinc oxide, rare earth oxides or hydroxides, etc. Favorable results can be obtained even when the compound is used as a carrier. Known carriers that have been proposed as preferred for obtaining cyclohexanes from monocyclic aromatic hydrocarbons can also be used.

The amount of catalyst metal supported on such a carrier is not particularly limited, but is usually 0.1 to 1
0% by weight is preferably used. Ruthenium in such a catalyst may be partially or entirely in a cation state, but it is preferably in a completely reduced metal state.

The present invention requires the presence of water. The amount of water varies depending on the reaction type, but it can be made to coexist from 0.01 to 100 times the weight of the commonly used monocyclic aromatic hydrocarbon. 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 forms a homogeneous phase under the reaction conditions, or the coexistence of an extremely large amount of water, will reduce the effect, and if the amount of water is too large, Since it is necessary to increase the size of the reactor, it is practically desirable to coexist 0.5 to 20 times by weight.

゛In addition, when coexisting with water, as in the known methods that have already been proposed, aqueous solutions of salts such as chlorides, sulfates, carbonates, phosphates, or hydroxides of various metals are used. May be used. In particular, the selectivity of cyclohexanes may be improved by using an aqueous solution of a strong acid salt such as sodium sulfate.

In the present invention, at least one alcohol is used as an additive. Examples of this alcohol include common alkyl and aralkyl alcohols, such as lower alcohols such as methanol and ethanol, higher alcohols such as dodecanol and stearyl alcohol, and polyhydric alcohols such as ethylene glycol, 1,4-butanediol and glycerin. Benzyl alcohol, allyl alcohol, ether alcohols such as methylcellosolve, halogenated alcohols such as trifluoroethanol, and even ethanolamine,
A very wide range of alcohols can be used, including amino alcohols such as triethanolamine.

By adding these alcohols and the zinc compound described below, the selectivity and yield of cyclohexenes are greatly improved. In particular, primary alcohols having 3 or more carbon atoms are preferably used. The amount used as an additive varies depending on the type of alcohol and the amount of coexisting water, but under the reaction conditions, an organic liquid phase mainly composed of raw materials and products and a liquid phase containing water form two phases. It is added in the region where it can be formed, and generally, l is added to the monocyclic aromatic hydrocarbon used.
Xl0-5 to 1 times by weight, preferably I Xl0-' to
It is 0.5 times the weight.

Substances that are easily converted into alcohols under the reaction conditions, such as esters such as ethyl acetate and butyl acetate, ketones such as acetaldehyde and benzaldehyde, and organic phosphoric acid esters such as tributyl phosphate, are also used. can.

The present invention requires the addition of at least one zinc compound in addition to the alcohols mentioned above. Here, as the zinc compound, various salts such as weak salts such as carbonates and acetates, strong salts such as hydrochlorides, nitrates, and sulfates are used, and zinc oxide, zinc hydroxide, sodium zincates, etc. being used effectively.

Here, zinc oxide can also be used as a carrier for ruthenium. The amount used is lXl relative to the water present during the reaction.
0 bow to 0.3 times the weight, preferably I Xl0-' to 0.
1 times the weight. It is not particularly necessary that the entire amount of the added zinc compound be dissolved in the water coexisting during the reaction.

As described above, the present invention uses a hydrogenation catalyst mainly containing ruthenium, water, and an alcohol and a zinc compound as additives in combination to obtain cyclohexene with extremely high selectivity and yield. Although the reason for this is not necessarily certain, it is thought that alcohols and zinc compounds dissolved in water are partially adsorbed on the ruthenium surface, exposing reaction active sites that are very advantageous for the production of cyclohexenes.

Among the conventional techniques mentioned above, for example, Japanese Patent Application Laid-open No. 50-14
No. 2536 proposes the use of an aqueous solution containing a zinc cation salt as part of the invention, but in the present invention, a surprising and unique effect is achieved by using a zinc compound and alcohol together. It is clear that the present invention is essentially different from the above-mentioned invention, since the present invention exhibits a significant improvement in the selectivity and yield of cyclohexenes. Furthermore, in JP-A No. 53-63350, when using a special catalyst containing at least one of the periodic table metals (1) and at least one of silver and copper, an aqueous solution of a zinc compound is Although there are descriptions regarding the use of lower alcohols such as methanol and ethanol, they are essentially different from the present invention because the catalyst is special and the lower alcohol is an inert substance unrelated to the reaction. The difference is clear.

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 fixed sum method. The reaction conditions are appropriately selected depending on the type and amount of the catalyst and additives used, but the hydrogen pressure is usually 1 to 200 ktr/cj G, preferably 10
~100 kg/cd G, and the reaction temperature ranges from room temperature to 250 °C, preferably from 100 to 200'C. In addition, the reaction time may be appropriately selected based on the actual target value of the selectivity and yield of the desired cyclohexene (although there is no particular restriction, it is usually several seconds to several hours).

(Effect of the invention) In the present invention, by using a hydrogenation catalyst mainly containing ruthenium, water, and at least one alcohol and at least one zinc compound as additives, monocyclic aromatic hydrocarbons can be produced. Cyclohexenes can be obtained with unprecedentedly high selectivity and yield, making it 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 in any way.

Examples 1 to 18 Hydrogenation catalyst 4 in which 1% by weight of ruthenium was supported on lanthanum hydroxide was placed in an autoclave with an internal volume IIl equipped with a stirrer.
．． 0g, 80ml of benzene, 1.14% by weight aqueous sodium sulfate solution 320a+1, alcohol and zinc compound, and after purging the inside of the autoclave with hydrogen several times, the temperature was raised to 150''C.Thereafter, hydrogen was injected under pressure to reduce the total pressure. was set at 50 kg/cd G, and the reaction was carried out with stirring at 1600 revolutions/min. The reaction solution was extracted over time from an extraction port installed in advance in the autoclave, and the composition of the oil phase was analyzed by gas chromatography. The conversion rate of benzene, selectivity and yield of cyclohexene were calculated.These results are shown in Table 1.

Table 1 4 available) Table 1 Comparative Examples 1 to 3 The same operations as Examples 1 to 18 were carried out except that one or both of alcohol and zinc compound as a converting agent was not added. I did it. The results are shown in Table 2.

Table 2 As shown above, it can be seen that the selectivity and yield of cyclohexene can be greatly improved by using both an alcohol and a zinc compound as additives.

Examples 19-22 Ruthenium chloride (RuCI, .3H
Example 1 except that 0.20 g of the metal ruthenium catalyst obtained by hydrolyzing 20) with an alkali and reducing it from hydrogen in water was used, and water was used instead of the sodium sulfate aqueous solution.
The same operations as in steps 1 to 18 were performed.

The results are shown in Table 3.

Table 3 Comparative Example 4 The same operations as in Examples 19 to 22 were performed except that 0.025 g of metal ruthenium catalyst was used and no alcohol and zinc compound were added. The conversion rate was 23.5%, the cyclohexene selectivity was 2.0%, the cyclohexene yield was 0.5%, and the reaction times were 48.0%, 0.5%, and 0.2% in this order at 20 minutes.

From these results, it is clear that the method of the present invention can greatly improve the selectivity and yield of cyclohexenes even if the hydrogenation catalyst does not have a particular carrier.

Comparative Example 5 The same operation as in Example 20 was performed except that 0.025 g of metal ruthenium catalyst was used and water was not allowed to coexist. The benzene conversion rate was 34.0% in a reaction time of 10 minutes.
Cyclohexene selectivity 10.1%, cyclohexene yield 3.4%, reaction time 20 minutes, 61.5%, 5.
4% and 3.3%.

Comparative Example 5 shows that the coexistence of water is necessary to obtain cyclohexanes with high selectivity and high yield.

Comparative Example 6 The same procedure as in Example 20 was carried out, except that the amount of water to be allowed to coexist was changed to Ig (this amount is a region where the raw materials and products, alcohol, and water form an almost homogeneous phase under the reaction conditions). When the operation was carried out, the benzene conversion rate was 28.6%, the cyclohexene selectivity was 19.4%, and the cyclohexene yield was 5.5% at a reaction time of 10 minutes, and 5% at a reaction time of 20 minutes.
They were 4.3%, 9.7%, and 5.3%.

Comparative Example 6 shows that when the liquid components form a homogeneous phase under the reaction conditions, the effect of the coexistence of water and the effect of adding alcohol and zinc compounds are significantly reduced.

Examples 23-24 The same operations as in Examples 19-22 were carried out, except that T-alumina and zinc oxide were used as the carrier for the hydrogenation catalyst and the amounts of each used were changed. At this time, the amount of ruthenium supported on each carrier was all 1% by weight.

Table 4 shows these and comparative examples corresponding to each.

As described above, even when γ-alumina or zinc oxide is used as a carrier, the effects of the additive of the present invention are similarly exhibited. In addition, when zinc oxide is used as a carrier, it is clear that zinc oxide itself plays the role of an additive, and that the selectivity and yield of cyclohexene are improved by the addition of alcohol. It also shows that there is no need for all of the to be dissolved in water.

Claims (1)

[Claims] Partial reduction of monocyclic aromatic hydrocarbons with hydrogen in the presence of a hydrogenation catalyst mainly containing ruthenium, water and additives, using at least one alcohol and at least one zinc compound as additives A method for producing a cycloolefin, characterized by: