JP2001010987A - Production of cyclopentene - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing cyclopentene by using cyclopentadiene as a raw material and partially hydrogenating the raw material with high conversion and selectivity to industrially advantageously produce the cyclopentene. SOLUTION: This method for producing cyclopentene comprises catalytically hydrogenating cyclopentadiene in a gas phase in the presence of a supported catalyst which comprises (1) at least one kind of metal element, or metal compound, selected from palladium, platinum and rhodium, and (2) at least one kind of metal element, or metal compound, selected from nickel, gold and molybdenum supported on a carrier. The above process is preferably combined with another process in which dicyclopentadiene is thermally decomposed in the presence of an inert solvent to be converted into the cyclopentadiene so that the resulting mixture of the cyclopentadiene with the inert solvent is used for producing the cyclopentene through the above process.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing cyclopentene. More specifically, the present invention relates to a method for producing cyclopentene by gas-phase catalytic hydrogenation of cyclopentadiene in the presence of a hydrogenation catalyst.

[0002]

2. Description of the Related Art Hitherto, methods for producing monoolefins by hydrogenating diolefins with molecular hydrogen have been reported in many documents. A method for producing cyclopentene by hydrogenating cyclopentadiene, which is a cyclic diolefin, in the gas phase has also been reported, and many hydrogenation catalysts used for the production method are known.

[0003] For example, Japanese Patent Publication No. 40-9005, Japanese Patent Publication No. 42-7254, and Japanese Patent Application Laid-Open No. 46-7267 show:
A method is described in which palladium and chromium, copper or titanium are supported on a carrier, the catalytic activity of palladium is reduced, and diolefins are selectively hydrogenated to convert them to monoolefins.

[0004] German Patent No. 1 181 700 describes copper, silver, zinc, cadmium, mercury, thallium, lead, antimony and / or copper, silver, zinc, cadmium, mercury, as catalysts for hydrogenating cyclic diolefin compounds to the corresponding monoolefin compounds. Alternatively, a palladium-supported catalyst to which a heavy metal such as iron is added is described.

Japanese Patent Publication No. 13703/1993 discloses that a carrier selected from α-alumina supported on magnesium, α-alumina and magnesium oxide contains (1) palladium and (2) 0.14- 5
A hydrogenation catalyst for cyclic diolefins in which one or more selected from the group consisting of ruthenium, rhodium, cobalt and rhenium by weight is supported in the form of a metal or a metal compound is described.

JP-A-49-88837 discloses that a surface area of 1
Manufacture of cyclopentene by selective hydrogenation of cyclopentadiene in the presence of molecular hydrogen in the gas phase using a catalyst in which palladium and iron are supported as active ingredients on magnesium oxide of not more than 00 m ² / g A method is described.

In Japanese Patent Publication No. 52-33627, a surface area of 1
It describes a method for producing cyclopentene in which a catalyst in which palladium and iron are supported on alumina of 00 m ² / g or less and where cyclopentadiene is partially hydrogenated at 70 ° C. or more in a gas phase.

Japanese Patent Publication No. 56-1292 discloses that a lithium / aluminum spinel having a lithium content of up to 2.6% by weight and an internal surface area of not more than 100 m ² / g is used as a carrier, and palladium is used as an active ingredient.
Or use a catalyst supported with titanium,
A method for producing cyclopentene by partially hydrogenating cyclopentadiene using molecular hydrogen in the gas phase at the above temperature is described.

Incidentally, the hydrogenation catalysts used in the above-mentioned prior arts are mainly composed of palladium. In general, palladium catalysts have sufficient activity to completely hydrogenate unsaturated hydrocarbon compounds such as diolefins, and even if they are used for a long time, they do not lose their activity. Used. However, when it is used as a catalyst for partial (selective) hydrogenation, the activity is often too high, and palladium itself is added by adding various other metal components to palladium as in the prior art. Is used with reduced catalytic activity.

However, even if a conventional hydrogenation catalyst comprising a metal component of a different kind from palladium is used, there are various disadvantages in partially hydrogenating cyclopentadiene. For example, the catalytic activity is still too high to generate saturated cyclopentane, or conversely, the activity is too low to reduce the conversion rate of cyclopentadiene and increase the reaction time, or impurities contained in cyclopentadiene, In particular, there is a disadvantage that the catalyst is easily poisoned and deactivated due to sulfur content. Therefore, in the industrial production of cyclopentene,
In fact, only extremely unsatisfactory results have been obtained.

[0011]

SUMMARY OF THE INVENTION In view of the above-mentioned problems of the prior art, an object of the present invention is to provide a process for producing a compound comprising cyclopentadiene as a raw material and partially hydrogenating the compound with high selectivity and conversion. It is an object of the present invention to provide a method for producing cyclopentene.

[0012]

Means for Solving the Problems In order to achieve the above object, the present inventors have intensively studied the relationship between the catalyst component used for hydrogenation of cyclopentadiene, the conversion of the raw material, and the selectivity of the reaction product. In addition, they have found that cyclopentene can be obtained very efficiently by hydrogenation using a multi-component supported catalyst composed of two or more specific metal simple substances or metal compounds, and completed the present invention. .

Thus, according to the present invention, there is provided a method for producing cyclopentene by subjecting cyclopentadiene to gas phase catalytic hydrogenation in the presence of a hydrogenation catalyst, wherein (1) palladium, platinum or rhodium is used as a hydrogenation catalyst. A carrier catalyst comprising at least one selected from a single metal or a metal compound and (2) at least one single metal or a metal compound selected from nickel, gold, and molybdenum supported on a carrier. A method for producing cyclopentene is provided.

In the process for producing cyclopentene of the present invention, dicyclopentadiene is thermally decomposed in advance in the presence of an inert solvent to form cyclopentadiene, and the resulting mixture of inert solvent and cyclopentadiene is used as a raw material as a raw material. Preference is given to phase-contact hydrogenation.

[0015]

Cyclopentadiene of the raw materials used in the manufacturing method of the embodiment of the present invention are known substances having a boiling point of 41 to 42 ° C., contained 15-20% in C ₅ fraction of naphtha cracked oil. The method for producing this raw material is not particularly limited, and a material obtained by any method can be used. Examples of the method for producing cyclopentadiene include a method in which dicyclopentadiene (a dimer of cyclopentadiene) is thermally decomposed or depolymerized.

Cyclopentadiene can be used alone or
Although it may be used after being diluted with an inert solvent which does not hinder the hydrogenation reaction of the present invention, it is preferable to use it after being diluted with an inert solvent. By diluting with an inert solvent, dimerization of cyclopentadiene can be suppressed. Examples of the inert solvent include aliphatic hydrocarbons, aliphatic ethers, aliphatic alcohols, aromatic hydrocarbons, aromatic ethers, and the like, with aliphatic hydrocarbons and aromatic hydrocarbons being preferred. These inert solvents may be used alone or in combination of two or more.

The aliphatic hydrocarbon is not particularly limited, but usually has 1 to 15 carbon atoms, preferably 3 carbon atoms.
10 to 10. More preferably, it is an aliphatic hydrocarbon having 5 to 8 carbon atoms, and specific examples thereof include n-pentane, isopentane, cyclopentane, n-hexane, cyclohexane, methylcyclohexane, n-heptane,
Isoheptane, cycloheptane, n-octane, isooctane, cyclooctane and the like can be mentioned.

The aromatic hydrocarbon is not particularly limited, but is usually one having a boiling point of 80 to 300 ° C, preferably one having a boiling point of 80 to 200 ° C. Also,
In addition to these, mononuclear aromatic hydrocarbons are preferred. Specific examples of the aromatic hydrocarbon include, for example, benzene, toluene, ortho-xylene, meta-xylene, para-xylene, 1,2,4-trimethylbenzene (pseudocumene), and 1,2,5-trimethylbenzene (mesitylene). No. Preferred among these are benzene, toluene and xylenes, with toluene being most preferred.

The amount of the inert solvent used is not particularly limited, but is usually 5 to 100 parts by weight of cyclopentadiene.
-3000 parts by weight, preferably 10-2000 parts by weight,
More preferably, it is 20 to 1000 parts by weight. When the amount of the inert solvent is less than 5 parts by weight based on 100 parts by weight of cyclopentadiene, there is a problem that the selectivity of cyclopentene in the hydrogenation step is reduced. Use beyond this is disadvantageous in terms of cyclopentene productivity.

In the hydrogenation reaction of the present invention, an inert gas which does not hinder the reaction can be used in addition to the inert solvent. Examples of the inert gas include a nitrogen gas, a helium gas, an argon gas, a carbon dioxide gas and the like. The amount used is not particularly limited, but is usually 0.1 to 20 mol, preferably 0.2 to 10 mol, more preferably 0.5 to 5 mol, per 1 mol of cyclopentadiene.

As a method of mixing the raw material cyclopentadiene and the inert solvent, a cyclopentadiene prepared in advance and an inert solvent may be mixed. However, as a pre-step of the gas phase catalytic hydrogenation of the present invention, Providing a step of thermally decomposing dicyclopentadiene to produce cyclopentadiene, and performing the first step in the presence of the inert solvent,
It is preferable to subject the resulting mixture of cyclopentadiene and inert solvent to gas phase catalytic hydrogenation without separation. By performing the thermal decomposition reaction of dicyclopentadiene in the presence of an inert solvent as described above, it is possible to suppress the formation of a polymer during the reaction, thereby suppressing the blockage of the reaction system line.

In the step of thermally decomposing dicyclopentadiene, a conventionally known method can be employed. Specifically, a mixture of dicyclopentadiene and an inert solvent is fed to a preheater and passed through a vaporizer and then a decomposer. The preheater, vaporizer, and decomposer do not necessarily have to be separate, and the temperature of each part of the same reactor may be a temperature suitable for each purpose.

In general, since the conversion and selectivity of the above-mentioned thermal decomposition reaction are good, the obtained reaction mixture can be directly subjected to gas-phase catalytic hydrogenation. After dicyclopentadiene and by-products are removed by distillation to obtain a mixture of cyclopentadiene and an inert solvent, the mixture may be subjected to a gas-phase catalytic hydrogen reaction.

The conditions for the thermal decomposition reaction are not particularly limited, and the reaction pressure (gauge pressure) is usually 0 to 40 kg / cm ² , preferably 0 to 20 kg / cm ² . The reaction temperature is usually from 200 to 450C, preferably from 250 to 400C.

The hydrogenation catalyst used in the present invention comprises (1) at least one kind of metal or a metal compound selected from palladium, platinum and rhodium, and (2) at least one kind of metal selected from nickel, gold and molybdenum. It is characterized in that it is a supported catalyst in which a simple substance or a metal compound is supported on a carrier, and it is essential to use the above (1) and (2) in combination. In the group (1), palladium is preferable, and in the group (2), nickel is preferable.

Here, the term "metal simple substance" refers to a metal that exists as a simple substance in a metal state without being ionized. The term “metal compound” refers to a compound in which a simple metal ionizes to form a salt or is oxidized to an oxide. The metal compound is not particularly limited as long as it can be dispersed in an appropriate dispersing solvent when supported on a carrier described later, but is usually a halide of a simple metal, a nitrate, a sulfate, a hydroxide, an oxide, Carboxylate, carbonate, ammonium salt,
And other compounds. These metal compounds may be anhydrous or hydrated.

Specific examples of the metal compounds of the group (1) include palladium chloride, palladium nitrate, palladium sulfate, palladium acetate, hexachloroplatinic acid (IV), platinum chloride (II), platinum chloride (IV), chloride Examples include potassium (II) platinate, platinum (II) bromide, platinum (IV) bromide, platinum (IV) hydroxide, platinum (II) oxide, rhodium trichloride, rhodium oxide, and the like. Of these, palladium compounds are preferred.

Specific examples of the metal compounds of the group (2) include nickel chloride, nickel bromide, nickel nitrate, nickel sulfate, nickel (II) oxide, nickel oxide (I
II), nickel carbonate, nickel formate, nickel acetate,
Nickel lactate, nickel naphthenate, nickel ammonium sulfate, gold (I) chloride, tetrachloroauric acid (II
I), gold (I) bromide, molybdenum (II) chloride, molybdenum (V) chloride, molybdenum oxide and the like. Of these, nickel compounds are preferred.

The quantitative ratio of the groups (1) and (2) is (1)
For 100 parts by weight of the group of (2), the group of (2) is usually in the range of 0.
0.1 to 500 parts by weight, preferably 0.1 to 300 parts by weight.
Parts by weight, more preferably 1 to 200 parts by weight.

In the production method of the present invention, it is essential that the metal simple substance or the metal compound is supported on a carrier before use. The type of the carrier is not particularly limited, and a carrier for a catalyst generally used industrially is used. For example, activated carbon, magnesium oxide, α-alumina, α-alumina supporting an alkaline earth metal, titania, etc., are exemplified. Α-alumina, α-alumina supporting an alkaline earth metal
Alumina is preferred. As the alkaline earth metal of the “α-alumina supporting an alkaline earth metal”, magnesium is preferable. These carriers can be used alone or
More than one species may be used in combination.

The shape of the carrier supporting the catalyst is not particularly limited, and may be a powdery substance or a granular substance. Examples of the external shape of the granular material include a sphere, a disk, a column, and a cylinder. The average particle size of the carrier is not particularly limited, and is appropriately selected according to the inner diameter of the reaction tube described later, and is usually 1 to 40 mm, preferably 2 to 20 mm. Although the specific surface area of the carrier is not particularly limited, if it is too large, the selectivity of cyclopentene decreases and cyclopentane is easily formed. If the specific surface area is too small, the conversion of cyclopentadiene tends to decrease. Usually, the specific surface area of the carrier supporting the catalyst is 1 to 100 m ^2.
/ G is appropriately selected.

The method for loading the catalyst component on the carrier is as follows. First, a metal compound corresponding to each catalyst component is treated with an aqueous solution of an acid such as water, hydrochloric acid, nitric acid or the like, an aqueous alkali solution, an alcohol, a ketone or the like.
Dissolve in organic solvents such as ethers, aliphatic carboxylic acids, esters and the like. Then, the solution is sprayed and dried on the carrier, or after the carrier is immersed in the solution and the metal compound is adsorbed on the carrier, the solvent is heated and evaporated, or the excess method is removed by a gradient method, filtration, or the like, It is a method of washing and drying if necessary. Two or more kinds of metal compounds may be simultaneously dissolved and supported, or may be sequentially supported. Further, the above-described carrying operation may be repeated several times as needed.

The thus obtained carrier supporting the metal compound is reduced with hydrogen, hydrazine, formaldehyde or the like to prepare a supported catalyst used in the hydrogenation reaction of the present invention. This reduction is preferably performed sufficiently until the supported metal compound is reduced to a simple metal. However, a metal compound that has not been reduced or a metal compound whose valence has been reduced by reduction may partially remain on the carrier. The term “metal simple substance or metal compound” in the present invention means that the catalyst is preferably composed mainly of a metal simple substance, but means that a metal compound may be mixed.

The amount of the metal alone or the metal compound supported on the carrier is not particularly limited, and is appropriately selected depending on the type of the metal carrier or the metal compound and the carrier. Usually, 0.01 to 20% by weight, preferably 0.05 to 15% by weight, and more preferably 0.1 to 20% by weight, based on the weight of the carrier in terms of metal simple substance
10% by weight.

In the hydrogenation reaction of the present invention, of the two carbon-carbon double bonds present in the molecule of the raw material cyclopentadiene, only one carbon-carbon double bond is selected by molecular hydrogen in the gas phase. This is a reaction for hydrogenation. The amounts of the raw materials and hydrogen for this reaction can vary greatly. However, usually, at least a stoichiometric amount of hydrogen is used, and the amount of hydrogen is appropriately selected in the range of 1 to 20 equivalents to the raw material. Preferably it is 1 to 10 equivalents.

This reaction employs a gas-phase batch (batch) reaction or a gas-phase flow reaction in which raw materials are continuously supplied to a reactor and reaction products are continuously withdrawn from the reactor. A flow reaction is preferred. The reactor used is not limited by its shape or material, but is a pressure-resistant reactor in the case of a batch reaction, and one or more reactors connected in series in the case of a flow reaction, for example, a multitubular fixed bed. It is a flow reactor. As a material for the reactor, for example, stainless steel is suitable.

When the above-mentioned multi-tube fixed bed flow reactor is employed, the inner diameter of the reaction tube is not particularly limited.
00 mm, preferably 7 to 200 mm, more preferably 10 to 100 mm. Also, the length of the reaction tube is not particularly limited, but is usually 0.1 to 10 m, preferably 0.2 to 7 m.

This reaction is an exothermic reaction, and the reaction temperature is not particularly limited. Usually, it is in the range of 30 to 500C. Preferably it is 50-450 degreeC, More preferably, it is 100.
３００300 ° C. When the reaction is carried out by a gas phase batch method, the contact time is usually 0.1 to 10 hours, preferably 0.2 to 10 hours.
~ 5 hours. In the case of performing by the gas phase flow method, usually,
It is 0.1 to 500 seconds, preferably 1 to 200 seconds. Reaction pressure (gauge pressure) is usually 0 to 10 kgf / c
m ² , preferably 0 to 5 kgf / cm ² , more preferably 0 to 3 kgf / cm ² .

When this reaction is carried out by a gas-phase flow reaction, the space velocity of the raw material (the value obtained by dividing the total flow rate of the raw material gas per hour by the packed volume of the catalyst (based on the empty cylinder)) is not particularly limited.
100 to 10,000 / hour is preferred, and 300 to 500
0 / hour is more preferred.

After the completion of the hydrogenation reaction, the desired product can be isolated by a conventional purification method such as distillation. The cyclopentene thus produced is useful as a raw material for producing various derivatives and also as a raw material for a cocatalyst for olefin monomer polymerization.

[0041]

EXAMPLES The present invention will be described below in detail with reference to examples, but the scope of the present invention is not limited by these examples.

In Examples and Comparative Examples, the conversion (%) of cyclopentadiene and the selectivity (%) and yield (%) of cyclopentene, which show the reaction results, were determined by the condensate (crude product) obtained by the reaction. Was calculated by the following formula based on the composition ratio determined by analyzing the gas chromatography. When the reaction results are compared, when the reaction conditions other than the catalyst are the same, the higher the conversion and the higher the selectivity, the more efficiently cyclopentene is produced.

Conversion rate = [1- (flow rate of cyclopentadiene at outlet of reaction tube (g / h)) / (flow rate of introduced cyclopentadiene (g / h))] × 100 selectivity = (cyclopentene at outlet of reaction tube) Flow rate (g / h)) ÷ (flow rate of converted cyclopentadiene (g / h)) × 100 yield = (the above conversion) × (the above selectivity) 率 100

The catalyst life in the hydrogenation reaction is determined by the position of the maximum reaction temperature (hot spot, hereinafter abbreviated as hs) in the reaction tube (distance from the gas inlet side end surface of the catalyst layer) to the catalyst from the catalyst layer inlet. After confirming in advance that the degree of reduction in catalyst activity can be estimated by the phenomenon of moving to the bed outlet, the hs moving speed (hereinafter referred to as hs moving speed) was measured and evaluated. That is, the lower the hs transfer rate, the longer the catalyst life, and it can be said that the catalyst is advantageous as a catalyst for producing cyclopentene.

Example 1 Preparation of hydrogenation catalyst A A palladium-nickel catalyst (catalyst A) using magnesium-supported α-alumina as a carrier was prepared as follows. 200 g of commercially available α-alumina was impregnated with 250 ml of an aqueous solution containing 8.36 g of magnesium chloride hexahydrate, dried and calcined at 600 ° C. for 5 hours in air to obtain magnesium-supported α-alumina (specific surface area of about 30 m). ² / g).

To this carrier, 1.66 g of palladium chloride,
4.05 g of nickel chloride hexahydrate and 40% of 35% hydrochloric acid
200 ml of acetone solution containing 1 l of 40% 35% hydrochloric acid
And dried at 120 ° C. This is hydrazine 1
It was reduced with an aqueous solution containing 0% by weight and 10% by weight of sodium hydroxide for 2 hours. Next, it was washed with water until chloride was completely removed, and dried at 120 ° C. for 2 hours. The resulting catalyst contained 0.5% by weight of palladium and 0.5% by weight of nickel.

Example 2 Preparation of hydrogenation catalyst B The procedure of Example 1 was repeated, except that 0.84 g of tetrachloroauric acid tetrahydrate was used instead of nickel chloride hexahydrate in Example 1. A palladium-gold catalyst (Catalyst B) was prepared. The resulting catalyst contained 0.5% by weight of palladium and 0.2% by weight of gold.

Example 3 Preparation of hydrogenation catalyst C Example 1 was repeated except that nickel chloride hexahydrate in Example 1 was replaced by 2.85 g of molybdenum (V) chloride.
A palladium-molybdenum catalyst (catalyst C) was prepared in the same manner as described above. The resulting catalyst contained 0.5% by weight of palladium and 0.5% by weight of molybdenum.

Comparative Example 1 Preparation of hydrogenation catalyst D A catalyst carrying only palladium (catalyst D) was prepared in the same manner as in Example 1 except that nickel chloride hexahydrate was not added. did. The resulting catalyst for comparison contained 0.5% by weight of palladium.

Comparative Example 2 Preparation of hydrogenation catalyst E The procedure of Example 1 was repeated, except that 3.56 g of ferrous chloride tetrahydrate was used instead of nickel chloride hexahydrate in Example 1. A palladium-iron catalyst (Catalyst E) was prepared.
The resulting catalyst contained 0.5% by weight of palladium and 0.5% by weight of iron.

Examples 4 to 6 Production of cyclopentene using hydrogenation catalysts A to C Using a dicyclopentadiene having a purity of 97% by weight diluted with toluene as a starting material, a vaporization section of a temperature controllable stainless steel tube made of a stainless steel tube was used. , "A pyrolysis unit of dicyclopentadiene", a "hydrogenation unit of cyclopentadiene", and a "product collection unit" in this order. The catalysts A to C obtained in Examples 1 to 3 were separately added to the hydrogenation part of the cyclopentadiene in the latter stage for about 6 hours.
The experiment was conducted by filling 0 ml and repeating the same operation.

First, a liquid in which dicyclopentadiene and toluene were mixed at a weight ratio of 2: 1 was introduced into a vaporizer heated to 220 ° C. at a flow rate of 3.3 g / min using a metering pump. Was vaporized. The vaporized mixture was immediately introduced into a pyrolysis tube made of stainless steel heated to 350 ° C., and dicyclopentadiene in the mixture was pyrolyzed to obtain cyclopentadiene. As a result of sampling and analyzing a part of the pyrolysis product, the conversion of dicyclopentadiene into cyclopentadiene was 98% (by weight).

The impurities in the pyrolysis product include:
Methyldicyclononadiene (0.15% by weight), methyldicyclopentadiene (0.09% by weight), norbornylacetylene (127 ppm), trimer of cyclopentadiene (110 ppm), sulfur-containing compound (as total sulfur) (0.6 ppm analyzed). No alteration due to thermal decomposition of the diluent toluene was observed.

Next, the pyrolysis gas was mixed with hydrogen (flow rate: 49.2 liters / hour) introduced from another pipe, and the stainless steel reaction tube (inner diameter: 23 mm, catalyst, immersed in an oil bath at 140 ° C.) (Length of layer about 150 mm). A thermocouple protection tube (outer diameter: 3.18 mm) was inserted into the reaction tube along the axial direction at the center of the cross section. The internal temperature of the catalyst layer was measured at 10 mm intervals by inserting a thermocouple into a protective tube and moving the same in the axial direction.
A condenser for cooling and collecting the target product was provided at the outlet of the reaction tube, and the condensed liquid was collected in a receiver.

The condensate obtained was analyzed by gas chromatography and the conversion ratio of cyclopentadiene (%), the selectivity of cyclopentene (%) and the yield (%) were determined by the above-mentioned formula based on the composition ratio. Was calculated. Also, based on the moving distance of the maximum reaction temperature (hs) in the catalyst layer per unit time recorded in the temperature recorder, the hs moving speed (mm / hour)
I asked. Table 1 shows the experimental results for each of the catalysts A to C.

[0056]

[Table 1]

Comparative Examples 3 to 4 Production of Cyclopentene Using Hydrogenation Catalysts D to E In Examples 4 to 6, the catalyst to be filled in the hydrogenation reaction section was replaced with Catalysts D to E obtained in Comparative Examples 1 and 2. Except for the same experiment, the conversion of cyclopentadiene (%),
The selectivity (%) and yield (%) of cyclopentene and the hs transfer rate (mm / hour) were determined. Table 1 shows the results of these experiments.

According to Table 1, the conversions, selectivities, and yields of the catalysts A to C of the present invention were larger than those of the catalysts D to E of the comparative examples, indicating excellent reaction results. Further, the hs transfer speed representing the catalyst life is a small value, which indicates that the catalyst life is long.

[0059]

According to the present invention, cyclopentene can be produced from cyclopentadiene with good yield and the catalyst life is long. In addition, by making the process combined with the step of preparing cyclopentadiene by thermally decomposing dicyclopentadiene, cyclopentene can be efficiently produced.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) // C07B 61/00 300 B01J 23/64 103X F-term (reference) 4H006 AA02 AC11 AC28 BA05 BA14 BA21 BA24 BA25 BA26 BA29 BA34 BA36 BA37 BB11 BB14 BB15 BC10 BC13 BE20 4H039 CA40 CB10

Claims (2)

[Claims] 1. A method for producing cyclopentene by gas-phase catalytic hydrogenation of cyclopentadiene in the presence of a hydrogenation catalyst, wherein the hydrogenation catalyst comprises (1) at least one kind selected from palladium, platinum and rhodium. A method for producing cyclopentene, comprising using a supported catalyst in which a carrier comprises a metal simple substance or metal compound and (2) at least one metal simple substance or metal compound selected from nickel, gold, and molybdenum. 2. Dicyclopentadiene is pyrolyzed to cyclopentadiene in the presence of an inert solvent, and a mixture of the obtained inert solvent and cyclopentadiene is converted into (1) at least one of palladium, platinum, and rhodium. Gas-phase catalytic hydrogenation in the presence of a supported catalyst comprising a single metal or metal compound and (2) at least one metal or metal compound selected from nickel, gold and molybdenum supported on a carrier A method for producing cyclopentene.