JP2000302703A - Preparation of cyclo-olefines - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain cyclo-olefin in high yield by hydrogenating monocyclic aromatic compounds using a rare-earth metal complex as a catalyst. SOLUTION: This cyclo-olefin is obtained by hydrogenating (A) a monocyclic aromatic compound (e.g. benzene, toluene, xylene, ethyl benzene, cumene, cymene, mesitylene or the like) using (B) a rare-earth metal (e.g. ytterbium, europium, praseodymium, samarium or the like) complex as the catalyst. The prescribed reaction is carried out by using of 5-80 pts.wt. component B to 100 pts.wt. component A at 320-473 deg.K for 0.5-10 hours under 0.5-10 MPa. The component B prepared by dissolving the rare-earth metal in liquid ammonium at 250-370 deg.K for 0.5-15 hours, is preferred. The hydrogen used in the hydrogenation is press-fitted into a reactor as a gas, preferably 2-30 mole is used per 1 mole of the component A.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing cycloolefins, and more particularly, to a method for producing cycloolefins that can selectively and in one step obtain cyclomonoene and / or cyclodiene. .

[0002]

2. Description of the Related Art Cyclomonoenes obtained by hydrogenating monocyclic aromatic hydrocarbons are useful as intermediates in organic chemical products, and are particularly important compounds as raw materials for polyamide and lysine. Further, cyclodiene obtained by hydrogenating a monocyclic aromatic hydrocarbon is also used as a raw material for a derivative of a 6-membered carbon ring having a plurality of substituents or a derivative by a Diels-Alder reaction, and further as a functional resin. It is a compound useful as a raw material for one diene polymer.

As a method for producing such a cycloolefin, there has been known a method for producing cyclohexene by hydrogenating benzene using a particulate catalyst made of metal ruthenium and water (Japanese Patent Laid-Open No. 61-1986). 50930
JP, JP-A-62-45544, JP-A-62-45544
81332, JP-A-62-205037).

However, in these production methods, in order to obtain the desired cyclohexene with a high selectivity, it is necessary to carry out the reaction in a two-phase system of benzene and water. There was a practical inconvenience of having to do it. In order to avoid this inconvenience and reduce the scale of the reactor, it was necessary to control the conversion of benzene to 20% or less. Moreover, even if the conversion of benzene is set to 20% or less,
The selectivity of cyclohexene is limited to 90% at the maximum, and there is a new problem that the load of the subsequent separation and purification step is increased.

As a catalyst for hydrogenating benzene, a rare earth metal prepared by a metal vapor deposition method (Lanthanoide)
Actinide Res., 1987 2., 79) and the combination of rare earth metals dissolved in liquid ammonia with silica or silica-alumina.
Supported (J. Chem. Soc. Chem. Commun., 1993, 1852)
However, although the selectivity of cyclohexene is 20% or less and the selectivity of cyclohexene is as high as 96% or more, there is a drawback that the conversion of benzene is extremely low.

[0006]

SUMMARY OF THE INVENTION The present invention solves such disadvantages of the prior art and provides a process for producing cycloolefins which can selectively and in one step obtain cyclomonoene and / or cyclodiene. It is intended to do so.

[0007]

Means for Solving the Problems In order to achieve the above object, the present inventor has focused on a hydrogenation catalyst for monocyclic aromatic hydrocarbons, and as a result of intensive studies, it has been found that a rare earth metal complex is used as a catalyst. As a result, they have found that the above object can be achieved, and have completed the present invention based on this finding.

That is, the present invention provides (1) a method for producing cycloolefins, which comprises hydrogenating a monocyclic aromatic hydrocarbon using a rare earth metal complex as a catalyst, and (2) a method wherein the rare earth metal complex is a rare earth metal complex. (1) The method for producing cycloolefins according to the above (1), which is prepared by dissolving a metal with liquid ammonia, and (3) the hydrogenation is carried out in the presence of ammonia. Alternatively, the present invention provides a method for producing the cycloolefin described in (2).

[0009]

Embodiments of the present invention will be described below. There is no particular limitation on the monocyclic aromatic hydrocarbon used in the present invention, and in addition to benzene, toluene, xylene, ethylbenzene, cumene, cymene, mesitylene, etc., can be mentioned lower alkyl group-substituted benzene,
Among them, benzene is preferred in view of the usefulness of the target product.

The rare earth metal complex used as the catalyst is not particularly limited, and examples thereof include complexes of rare earth metals such as ytterbium, europium, praseodymium, and samarium. Among them, complexes of ytterbium and europium can be used as preferred catalysts. . These rare earth metals may be used alone or in combination of two or more.

In preparing the catalyst, it is not necessary to employ a special method. However, usually, it is preferable that the catalyst is prepared by dissolving a rare earth metal in liquid ammonia. In this case, the rare earth metal is dissolved in liquid ammonia. It is desirable to ripen it for a certain period of time after the aging. If aging is omitted, the catalytic activity may not be sufficiently exhibited. The dissolution temperature is usually from 250 to 370K, preferably from 260 to 370K.
300 ° K, and the aging temperature is almost the same. The aging time is usually 0.5 to 15 hours, preferably 1 to 15 hours.
12 hours.

If the treatment is carried out outside the range of these conditions, the catalytic activity may decrease, which is not desirable.
After the rare earth metal is dissolved in liquid ammonia and aged, the liquid ammonia is removed to obtain a rare earth metal complex as a precipitate. The form of the catalyst is not limited, and the obtained precipitate can be used as it is, or in the form of powder or granules. However, in consideration of the contact reaction, the powder or granules are preferably used.

It is not necessary to use the catalyst supported on a carrier, and this is one of the features of the present invention. In the present invention, cycloolefins are produced by taking the above monocyclic aromatic hydrocarbon and the above-mentioned catalyst into a reaction vessel and reacting them under a hydrogen atmosphere to hydrogenate the monocyclic aromatic hydrocarbon.

The amount of the catalyst used is not particularly limited, and is usually 5 to 80 parts by weight, preferably 10 to 50 parts by weight, per 100 parts by weight of the monocyclic aromatic hydrocarbon. If the amount is less than 5 parts by weight, both the conversion of the monocyclic aromatic hydrocarbon and the selectivity of the cycloolefin tend to decrease. If the amount exceeds 80 parts by weight, the effect corresponding to the increase cannot be expected. There are no particular restrictions on other reaction conditions, but the reaction temperature is 320 to 473 ° K, preferably 350 to 42K.
0 ° K, the reaction time is 0.5 to 10 hours, preferably 1 to 7 hours, the reaction pressure is 0.5 to 10 MPa,
Preferably, 1 to 5 MPa is employed.

Incidentally, hydrogen is usually injected into the reaction vessel as a gas, and the pressure is increased to the above-mentioned reaction pressure. The amount used is 2 to 30 mo per 1 mol of the monocyclic aromatic hydrocarbon.
1, preferably 3 to 15 mol. If the amount is less than 2 mol, the desired cycloolefin may not be obtained, and even if the amount exceeds 30 mol, the effect of the increased amount cannot be expected.

In the present invention, by coexisting ammonia in the hydrogenation reaction system, the catalytic activity can be remarkably improved, and good results can be obtained.
The amount of ammonia added is 100 to 1000 parts by volume, preferably 200 to 600 parts by volume, in terms of gas, per 1 part by volume of the monocyclic aromatic hydrocarbon. If the amount is less than 100 parts by volume, the expected improvement in the catalytic activity may not be observed,
Even if it exceeds 1,000 parts by volume, it is not possible to expect an improvement in the catalytic activity corresponding to the increase in the amount.

According to the present invention, monocyclic aromatic hydrocarbons such as benzene, toluene, xylene, cumene, etc.
Cyclohexene and / or cyclohexadiene, methylcyclohexene and / or methylcyclohexadiene, dimethylcyclohexene and / or dimethylcyclohexadiene, isopropylcyclohexene and / or isopropylcyclohexadiene, respectively, can be obtained in high yield, and the hydrogenation reaction system The revolutionary cyclodiene that the coexistence of ammonia improves the catalytic activity and enables better reaction results to be obtained, and also enables the selective production of cyclodienes corresponding to monocyclic aromatic hydrocarbons. Is provided.

The above-mentioned hydrogenation reaction can be carried out irrespective of the type of reaction, such as a batch system, a semi-batch system or a continuous system.

[0019]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. Example 1 In a 50 ml stainless steel autoclave replaced with nitrogen gas, 0.5 g of ytterbium (purity: 99.9%, manufactured by Santoku Metal Industry Co., Ltd.) was added, and ammonia (manufactured by Iwatani Corporation, ammonia gas) was added. Purified with calcium oxide and further treated with sodium hydroxide) 1
350 cm ³ was liquefied and filled to dissolve ytterbium, and then aged for 1 hour to obtain a precipitate.

Next, ammonia was removed from the autoclave to prepare a catalyst and a ytterbium complex. The catalyst thus prepared was taken in a 50 ml stainless steel autoclave, and 2 ml of benzene (manufactured by Wako Pure Chemical Industries, Ltd., which was twice distilled in the presence of sodium metal) was added. Then, the pressure was increased to 3 MPa with hydrogen gas, and the reaction was carried out with stirring at 393 ° K for 3 hours. After the completion of the reaction, the reaction product was analyzed by gas chromatography. As a result, the conversion of benzene was 8.5% and the selectivity of cyclohexene was 95%.

Example 2 A reaction was carried out in the same manner as in Example 1 except that the aging time was changed to 3 hours in the preparation of the catalyst in Example 1.
The benzene conversion was 10.5% and the cyclohexene selectivity was 85%.

Example 3 In the preparation of the catalyst in Example 1, the aging time was 12
The reaction was carried out in the same manner as in Example 1 except that the reaction time was 6 hours. The benzene conversion is 4.5%,
The cyclohexene selectivity was 89%.

Example 4 A catalyst was prepared in the same manner as in Example 1 except that europium was used instead of ytterbium in the preparation of the catalyst in Example 1, and a europium complex was obtained. A reaction was carried out in the same manner as in Example 1 using this catalyst. Benzene conversion is 1.7% and cyclohexene selectivity is 96.
%Met.

Embodiment 5 Ammonia gas 1000 cm ³ was added to an autoclave for 27 minutes.
The reaction was carried out in the same manner as in Example 1 except that the mixture was liquefied and charged at 3 ° K. Benzene conversion was 16.6%, cyclohexene selectivity was 85%, cyclohexadiene selectivity was 14%.
%Met.

Example 6 A reaction was carried out in the same manner as in Example 5 except that the catalyst prepared in Example 4 was used. Benzene conversion is 4
%, Cyclohexene selectivity was 3%, and cyclohexadiene selectivity was 97%.

Example 7 The preparation of the catalyst in Example 4 was repeated except that the aging time was 3 hours and the reaction temperature was 364 ° K.
The reaction was carried out in the same manner as described above. Benzene conversion is 1.8
%, Cyclohexene selectivity was 1%, and cyclohexadiene selectivity was 99%.

[0027]

According to the present invention, the cycloolefins which can be obtained by hydrogenating a monocyclic aromatic hydrocarbon to obtain the corresponding cyclomonoene and / or cyclodiene selectively and in high yield in a single-step reaction Manufacturing methods are provided and make a great contribution to the manufacturing chemical industry.

Claims (3)

[Claims] 1. A process for producing cycloolefins, comprising hydrogenating a monocyclic aromatic hydrocarbon using a rare earth metal complex as a catalyst. 2. The process for producing cycloolefins according to claim 1, wherein the rare earth metal complex is prepared by dissolving a rare earth metal with liquid ammonia. 3. The process for producing cycloolefins according to claim 1, wherein the hydrogenation is carried out in the presence of ammonia.