JPS6150930A - Production of cycloolefin - Google Patents

Abstract

PURPOSE:To produce the titled compound in high yield and selectivity, by the partial reduction of a monocyclic aromatic hydrocarbon with hydrogen in the presence of water and a zinc compound, using a hydrogenation catalyst consisting of a crystalline metallic ruthenium having a specific average crystal particle diameter and/or coagulated particles thereof. CONSTITUTION:A cycloolefin useful especially as a raw material of polyamide and lysine, etc., especially cyclohexene, is produced by the partial reduction of a monocyclic aromatic hydrocarbon with hydrogen in the presence of a hydrogenation catalyst composed mainly of ruthenium, water, and at least one zinc compound. In the above process, the selectivity and the yield of the objective compound can be improved using metallic ruthenium crystal having an average crystal particle diameter of <=200Angstrom , especially <=100Angstrom and/or coagulated particles thereof, as the above catalyst, and adding at least one kind of alcohol to the reaction system.

Description

Detailed Description of the Invention (Field of Industrial Application) 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 for organic chemical industry products, and are particularly important as raw materials for polyamides and lysine.

(Prior art) As a method for producing such cyclohexanes, for example,
(l) 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), (2) Supported on oxides of nickel, cobalt, chromium, titanium, or zirconium. (3) Copper,
A method using a ruthenium catalyst containing silver, cobalt, or potassium, water, and a phosphoric acid compound (Japanese Patent Publication No. 5
6-4536), (4) Method using a ruthenium catalyst, water, and cobalt sulfate (Japanese Unexamined Patent Publication No. 57-130)
In order to increase the selectivity of cyclohexene, which is the objective of Japanese Patent Publication No. 926), it is essential to keep the conversion rate of raw materials extremely low. Currently, it is not a manufacturing method.

(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, by using metal ruthenium crystallites and/or aggregated particles thereof having an average crystallite diameter of 200 Å or less as a hydrogenation catalyst, and carrying out the reaction in the coexistence of water and at least one zinc compound. They discovered that cyclohexanes can be obtained with unprecedented selectivity and yield. It has also been found that by using at least one type of alcohol as an additive, both the selectivity and the yield can be greatly improved.

According to the method of the present invention, by appropriately selecting the reaction conditions and the conversion rate of monocyclic aromatic hydrocarbons, cyclohexanes can be obtained with high selectivity and high yield, and surprisingly, the yield is It is possible to select conditions under which the ratio is 40% or more.

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.

The hydrogenation catalyst in the present invention is metal ruthenium crystallite and/or aggregated particles thereof, and its ffi'i
The crystallites have an average crystallite diameter of 200 angstroms or less, preferably 150 angstroms or less, and more preferably 100 angstroms or less. Further, the metal ruthenium particles themselves may be crystallites of 200 angstroms or less, or may be primary particles consisting of aggregates thereof. Furthermore, secondary particles formed by agglomeration of these secondary particles are also effective. Various methods are known for producing metal crystallites having such small crystallite diameters and/or aggregated particles thereof, not only for ruthenium.

For example, metals are heated and evaporated in an inert gas under low pressure,
Method of obtaining by cooling in gas [Applied Physics Vol. 42, 1
067 (1973)], a method of thermally reducing metal salts in alcohol in the presence of a protective colloid (Ch.
Em, Lett, 1976, p. 905), a method in which the metal is vaporized by heating under high vacuum and condensed with the vapor of a suitable solvent [J, Am, Chem.
Soc.

98, p. 1021 (1976)], these methods are useful as manufacturing methods in which the crystallites are small and the fine particles composed of the crystallites themselves are extremely small. is also used.

In addition, a convenient method, for example, (1) adding a highly concentrated alkali to an aqueous solution of ruthenium chloride under high-speed stirring, and reducing the precipitated black precipitate with hydrogen in water to produce metal ruthenium crystallites and/or or a method for obtaining aggregated particles thereof (J, Chem, Tech.

Biorechannel, + 31 + 691 pages (198
2)] and (2) a method in which a carrier on which metal ruthenium is supported in advance is dissolved in an appropriate solvent to obtain metal ruthenium crystallites and/or aggregated particles thereof as a dissolution residue. These methods (1) and (2) have the advantage that the secondary particles of aggregated crystallites have an appropriate particle size and can be easily isolated and stored by filtration etc.
It is also preferably employed in the method of the present invention.

In this way, metallic ruthenium crystallites and/or agglomerated particles thereof having an average crystallite diameter of 200 angstroms or less can be obtained. It is calculated from the Debye-Scherrer equation from the spread of . The crystallite diameter may be 200 angstroms or less, and the lower limit value is larger than the theoretical crystal unit, and is realistically 10 angstroms or more.

Further, other metals may be mixed as co-catalysts during or after the preparation of the metal ruthenium crystallites and/or aggregated particles thereof as described above. The cocatalysts are known per se, such as elements of group 1 of the periodic table, copper, silver, chromium, vanadium, gold, etc., and the gist of the present invention is not impaired by their inclusion. If such other metals are mixed during preparation,
The effect of reducing the crystallite diameter of metal ruthenium may be obtained.

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, it is also possible to use aqueous solutions of salts such as chlorides, sulfates, carbonates, and phosphates of various metals, or hydroxides, as in known methods that have already been proposed. good. 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, in addition to the hydrogenation catalyst and water, at least one
The presence of a species of zinc compound is required. Here, as the zinc compound, various salts are used, such as weak acid salts such as carbonates and acetates, and strong acid salts such as hydrochlorides, nitrates, and sulfates.
In addition, zinc oxide, zinc hydroxide, sodium zincate, etc. are also effectively used. The amount used is 1 x 10-' to 0.3 times the weight of water coexisting during the reaction, preferably 1
X10-' to 0.1 times. It is not particularly necessary that the entire amount of the zinc compound used be dissolved in the water coexisting during the reaction.

Furthermore, in the present invention, at least one
The use of seed alcohols improves the selectivity and yield of cyclohexanes even further.

This alcohol includes general alkyl and aralkyl alcohols, from lower alcohols such as methanol and ethanol to higher alcohols such as dodecanol and stearyl alcohol, ethylene glycol,
Polyhydric alcohols such as glycerin, benzyl alcohol, allyl alcohol, etc. can be used, as well as ether alcohols such as methylcellosolve, halogenated alcohols such as trifluoroethanol, and even ethanolamine and triethanolamine. A very wide range of alcohols can be used, including amino alcohols. 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, there are two phases: an organic liquid phase mainly composed of raw materials and products, and a liquid phase containing water. It is generally added in an amount of txto-'- by weight, preferably lXl0-' to 0.5 times the weight of the monocyclic aromatic hydrocarbon used.

Substances that are easily converted into alcohols under reaction conditions, such as esters such as ethyl acetate and butyl acetate, ketones such as acetaldehyde and benzaldehyde, and organic phosphate esters such as tributyl phosphate, etc. Can be used.

As described above, the present invention comprises a hydrogenation catalyst containing metal ruthenium crystallites having an average crystallite diameter of 10 to 200 angstroms and/or aggregated particles thereof, water, a zinc compound, and an alcohol as an additive. use,
Cyclohexenes can be obtained with extremely high selectivity and yield. The reason for this is not necessarily clear, but as the crystallite size becomes smaller, the number of sites on the crystallite surface suitable for partial reduction of monocyclic aromatic hydrocarbons increases, and furthermore, the area on the crystallite surface that is suitable for partial reduction of monocyclic aromatic hydrocarbons increases. It is also thought that a part of the adsorbed on the crystallite surface, exposing reactive active sites that are very advantageous for the production of cyclohexenes.

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 stationary phase 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 kg/cniG, preferably 10 to 100 kg/cniG.
kg/cm! G range, and the reaction temperature is room temperature to 25
0°C, preferably in the range of 100-200'C.

In addition, the reaction time may be appropriately selected based on the actual target values for the selectivity and yield of the desired cyclohexene.
There is no particular limit, but it is usually several seconds to several hours.

(Effects of the Invention) In the present invention, a hydrogenation catalyst containing metallic ruthenium crystallites and/or aggregated particles thereof having an average crystallite of 200 angstroms or less, preferably 150 angstroms or less, and more preferably 100 angstroms or less. water, at least one zinc compound,
More preferably, by using at least one kind of alcohol as an additive, cyclohexanes can be obtained from monocyclic aromatic hydrocarbons with unprecedentedly high selectivity and yield, which is extremely valuable industrially. It is.

(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 1-6 1% aqueous solution of ruthenium chloride (RuC1s 3HzO) II! was strongly stirred using a Teflon-coated turbine blade stirrer, and 150 ml of a 30% caustic soda aqueous solution was instantly added thereto, and the mixture was heated to 80° C. and stirred for 3 hours.

After cooling to room temperature and allowing it to stand still, removing the supernatant liquid, the remaining liquid containing the black precipitate was made up to 500 ml with water, and this was charged into a Teflon-coated Il autoclave, and the total pressure was increased to 50 kg with hydrogen. / cat G and reduced at 150°C for 2 hours. This solution was filtered under an argon atmosphere, washed several times with water, and then filtered under an argon atmosphere.
The mixture was dried at 80° C. to obtain 3.7 g of a black metal ruthenium crystallite agglomerated particle hydrogenation catalyst.

The average crystallite diameter was calculated from the line width expansion of the X-ray diffraction pattern of this catalyst, and was found to be 43 angstroms.

Hereinafter, this will be referred to as catalyst A.

After filtering the black precipitate before reduction in the preparation of Catalyst A, crystallites were grown while being reduced in a hydrogen stream.

The average crystallite diameter was calculated from the spread of the line width of the agglomerated particle X-ray diffraction pattern of the obtained metal ruthenium crystallites.
It was 135 angstroms. Hereinafter, this catalyst will be referred to as catalyst B.

Soak lanthanum hydroxide powder in ruthenium chloride aqueous solution,
After adsorbing ruthenium, using an autoclave,
Reduction was carried out at 150° C. and hydrogen pressure of 50 kg/cni G to obtain lanthanum hydroxide carrying 3% by weight of metal ruthenium. 50 g of this powder was gradually dissolved in 1 l of 20% nitric acid, and the black material that flaked off and precipitated was centrifuged and filtered to obtain aggregated particles of metal ruthenium crystallites. The average crystallite diameter was calculated from the X Hjn diffraction pattern of this, and was found to be 88 angstroms. Hereinafter, this catalyst will be referred to as catalyst C.

Next, the catalyst ASBSC prepared above was placed in a Teflon-coated autoclave with an inner volume of 11 and equipped with a stirrer.
200mg of either, 80ml of benzene, 32ml of water
After charging 0 ml and a zinc compound and purging the inside of the autoclave with hydrogen several times, the temperature was raised to 150°C. Hydrogen was injected to make the total pressure 50 kg/cra G,
The reaction was carried out with stirring at 1600 rpm, and the reaction solution was extracted over time from an outlet previously installed in the autoclave, and the composition of the oil phase was analyzed by gas chromatography. These results are shown in Table 1.

After the reaction was completed, hydrogenation catalysts A and C were recovered, and the average crystallite diameters were calculated from their X&'51 diffraction patterns, and it was found that there was almost no change in the crystallite diameters in either case compared to those before use.

Table 1 Comparative Example 1 Ruthenium black manufactured by Nippon Engelhard Co., Ltd. (average crystallite diameter of 500 angstroms or more) as a hydrogenation catalyst
The same operation as in Example 1 was carried out except that 500 mg was used, and the benzene conversion rate was 5.5 in the reaction time of 30 minutes.
7%, cyclohexene selectivity 18.0%, cyclohexene yield 1.0%, 9.8%, 10.5% at 60 minutes.
%, 1.0%, 90 minutes, 15.0%, 6.4%
, 0.96%.

As described above, the metallic ruthenium crystallites or aggregated particles thereof having the average crystallite diameter pointed out in the present invention,
It turns out that it is an extremely advantageous catalyst for the production of cyclohexenes.

Comparative Example 2 The same operation as in Example 1 was performed except that 25a+g of Catalyst A was used and no zinc compound was used. The benzene conversion rate was 24.2% and the cyclohexene selectivity was 3.2% in a reaction time of 10 minutes. 5%, cyclohexene yield 0.8%, 20
In minutes, they were 48.3%, 1.2%, and 0.6%, and in 30 minutes, they were 71.1%, 0.7%, and 0.5%, in that order.

Comparative Example 2 shows that the coexistence of a zinc compound significantly improves the selectivity and yield of cyclohexenes.

Examples 7 to 13 Example 4 except that various alcohols were added as additives.
The same operation was performed. These results are shown in Table 2.

Table 2 From Table 2, it can be seen that the addition of alcohol further improves the selectivity and yield of cyclohexenes.

Claims (2)

[Claims] (1) When a monocyclic aromatic hydrocarbon is partially reduced with hydrogen in the presence of a hydrogenation catalyst mainly containing ruthenium, water and at least one zinc compound, crystallites with an average size of 200 angstroms or less are used as a hydrogenation catalyst. A method for producing a cycloolefin, comprising using metal ruthenium crystallites having a diameter and/or aggregated particles thereof. (2) When a monocyclic aromatic hydrocarbon is partially reduced with hydrogen in the presence of a hydrogenation catalyst mainly containing ruthenium, water and at least one zinc compound, crystallites with an average size of 200 angstroms or less are used as a hydrogenation catalyst. A method for producing a cycloolefin, comprising using metal ruthenium crystallites having a diameter and/or aggregated particles thereof, and using at least one alcohol as an additive.