JP2001335527A - Method for producing cyclopentanone - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for industrially advantageously producing cyclopentanone in a simple process from cyclopentanol in high selectivity using a catalyst containing copper as an active ingredient. SOLUTION: This method for producing cyclopentanone comprises vapor phase dehydrogenation of cyclopentanol in the presence of a catalyst containing copper as an active ingredient; wherein the catalyst is such that the crystal grain size of the copper oxide or copper contained therein is <=0.13 nm and the specific surface area thereof >=15 m2/g, being preferably used for the reaction without reduction treatment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing cyclopentanone. More specifically, the present invention relates to a method for producing cyclopentanone by performing a gas phase dehydrogenation reaction of cyclopentanol in the presence of a catalyst containing copper as an active component.

[0002]

2. Description of the Related Art Conventionally, a method for obtaining the corresponding cyclohexanone or cyclopentanone by dehydrogenating cyclohexanol or cyclopentanol in the presence of a copper-containing catalyst is known.

For example, Japanese Patent Application Laid-Open No. Sho 56-20541,
JP-A-58-157741 proposes using a copper-chromium acid compound as a catalyst in a method for producing cyclohexanone by dehydrogenating cyclohexanol. JP-A-61-282334 proposes a method for converting cyclohexanol to cyclohexanenone using a catalyst containing copper oxide and zinc oxide.

JP-A-58-203932 discloses that cyclopentanol is dehydrogenated at a high temperature in the presence of a copper-based dehydrogenation catalyst to produce cyclopentanone in the presence of n-pentanal. After dehydrogenating cyclopentanol, the reaction product is purified by distillation.
-A method for producing cyclopentanone, in which pentanal is recovered from the top and a part thereof is circulated to the reaction system, while the bottom component containing cyclopentanone is distilled again to obtain cyclopentanone as the top component. Has been described.

Further, Japanese Patent Application Laid-Open No. 59-7129 discloses that cyclopentanol is dehydrogenated at a high temperature in the presence of a copper-based dehydrogenation catalyst to produce cyclopentanone. A method for producing cyclopentanone in which cyclopentanol is dehydrogenated in the presence of the above primary alcohol and aldehyde is disclosed.

Incidentally, a catalyst containing copper as an active component, such as a copper-chromium catalyst and a copper-zinc catalyst, has the advantage of being inexpensive and having high activity. However, when applied to the production of cyclohexanone or cyclopentane, there is a problem that by-products are generally easily formed and the reaction selectivity is low.

Further, when a catalyst containing copper as an active component is used for producing cyclopentanone, there is a problem in sustaining the catalytic activity. Therefore, Japanese Patent Application Laid-Open No.
In the production methods of JP-A No. 2 and JP-A-59-7129, the durability of the catalytic activity is improved by coexisting another type of alcohol or aldehyde in the reaction system. However, such a method has a disadvantage that the manufacturing process is complicated.

[0008]

SUMMARY OF THE INVENTION In view of the above-mentioned problems of the prior art, an object of the present invention is to use a catalyst containing copper as an active ingredient, obtain a high reaction selectivity from cyclopentanol, and have a simple process. An object of the present invention is to provide a method for producing cyclopentanone industrially advantageously by a process.

[0009]

Means for Solving the Problems In order to achieve the above-mentioned object, the present inventors have conducted a gas phase dehydrogenation reaction of cyclopentanol in the presence of a catalyst containing copper as an active ingredient to convert cyclopentanone into cyclopentanone. As a result of intensive studies on the relationship between the properties of the catalyst and the reaction results in the production method, it was found that the copper oxide or the crystal grain size of copper contained in the catalyst, and the specific surface area of the catalyst greatly affected the selectivity of cyclopentanone. Was found. Further, the present inventors have found that cyclopentanone can be produced extremely efficiently without deactivating the catalyst by combining the crystal grain size of copper oxide or copper and the specific surface area of the catalyst in a specific range. It was completed.

Thus, according to the present invention, in a method for producing cyclopentanone by subjecting cyclopentanol to a gas phase dehydrogenation reaction in the presence of a catalyst containing copper as an active component, the oxidation catalyst contained as the catalyst is contained. Copper or copper crystal grain size of 0.13 nm or less and specific surface area of 15 m
There is provided a method for producing cyclopentanone, which comprises using a catalyst of ² / g or more. It is preferable that the catalyst is not subjected to a reduction treatment as a step before the gas phase dehydrogenation reaction.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (Raw material cyclopentanol and diluent) In the present invention, cyclopentanol used as a raw material is a known substance having a boiling point of 139 to 140 ° C. The method for producing cyclopentanol is not particularly limited. For example, cyclopentanol obtained by a hydration reaction of cyclopentene can be used.

When cyclopentanol is used alone,
It may be used after being diluted with a diluent that does not hinder the dehydrogenation reaction, that is, an inert gas and / or an inert solvent. As the inert gas, nitrogen, argon, helium,
Although carbon dioxide is mentioned, nitrogen, helium and the like are preferable. 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.

The aliphatic hydrocarbon used as the diluent is not particularly limited, but is usually an aliphatic hydrocarbon having 1 to 15 carbon atoms, preferably 3 to 10 carbon atoms, more preferably 5 to 8 carbon atoms. Specific examples thereof include n-pentane, isopentane, cyclopentane, n-hexane, cyclohexane, methylcyclohexane, n-heptane, isoheptane, cycloheptane, n-octane, isooctane,
Cyclooctane and the like.

The aromatic hydrocarbon used as the diluent is not particularly limited, but usually has a boiling point of 80 to 200 ° C. Further, it is preferably a monocyclic aromatic hydrocarbon. Specific examples include benzene, toluene,
Ortho-xylene, meta-xylene, para-xylene, 1,
2,4-trimethylbenzene (pseudocumene), 1,
2,5-trimethylbenzene (mesitylene) and the like. Among them, benzene, toluene, xylene and the like are preferable, and toluene is more preferable.

The amount of the diluent used is not particularly limited. The amount of the inert gas used is usually 0.1 to 20 mol, preferably 0.2 to 20 mol per mol of cyclopentanol.
It is 10 mol, more preferably 0.5 to 5 mol. The amount of the inert solvent used is usually 5 to 3000 parts by weight, preferably 10 to 2000 parts by weight, more preferably 20 to 1000 parts by weight based on 100 parts by weight of cyclopentanol.
Parts by weight. The diluents may be used alone or in combination of two or more.

The method for vaporizing the raw material cyclopentanol is not particularly limited. What is necessary is just to utilize the vaporization apparatus usually used industrially. When using a diluent,
Mixing may be performed before evaporating cyclopentanol, or after evaporating cyclopentanol in advance.

(Catalyst Containing Copper) The catalyst used in the present invention contains copper as an essential element. The crystal grain size of copper oxide or copper contained in the catalyst is 0.13 nm or less (= 1.3
Å or less), and the specific surface area of the catalyst is 15 m ² / g or more. Although the oxidation-reduction state of copper is not particularly limited, it is preferable not to perform a reduction treatment before using a catalyst in a gas phase dehydrogenation reaction described later. That is, copper, which is an essential element, is preferably used in the reaction as copper oxide.

In the context of the present specification, the term "crystal grain size" means the crystal grain size calculated by the Debye-Scherrer equation based on the diffraction line width obtained by X-ray diffraction of a catalyst powder.
"Specific surface area" refers to the surface area per gram of catalyst measured by the BET method.

Further, "copper oxide or copper has a crystal grain size of 0.1.
The expression “13 nm or less” means that the crystal grain size of copper oxide or copper contained in the catalyst is 0.13 nm or less before, during, or after the reaction. That is, as described above, since the catalyst is preferably used without reduction treatment, copper as an essential element is subjected to the reaction in the form of copper oxide.
It means that it is 13 nm or less. In addition, in the reaction of the present invention, hydrogen is by-produced in the reaction system, and copper oxide is reduced by hydrogen and gradually changed to copper. Means that

The catalyst used in the present invention usually contains 15% by weight or more of copper. In addition to copper, zinc, chromium,
It may contain a metal element having a co-catalytic action, such as manganese, iron, cobalt, nickel, lead, tin, molybdenum, an alkali metal, or an alkaline earth metal. These metal elements may be used as a simple metal or a metal oxide. Considering the selectivity of cyclopentanone,
As the metal element used in combination with copper, zinc, chromium and the like are preferable, and zinc is more preferable.

The method for preparing the catalyst is not particularly limited.
Evaporation and drying methods, coprecipitation methods, kneading methods, impregnation methods, Raney alloy development methods, metal fine powder sintering methods, and the like can be employed. The shape of the catalyst is not particularly limited, and can be used in the form of a powder at an appropriate stage in the catalyst preparation process, or by molding according to a known method such as tableting, extrusion, and rolling.

The catalyst may be used as it is, or may be used by being supported on a known carrier. As a carrier,
Carriers that do not exhibit catalytic activity for the self-aldol condensation (side reaction) of cyclopentanone, which is the target substance, are preferred, such as silica, alumina, titania, zirconia, magnesia, diatomaceous earth, pumice, aluminum silicate, activated carbon, and carbonaceous carriers. Is mentioned.

The particle size of the catalyst may be appropriately selected depending on the inner diameter of a reaction tube described later, and the average particle size is 1 mm to 40 mm.
mm is preferable, and 2 mm to 20 mm is more preferable.

(Gas-Phase Dehydrogenation Reaction) The reaction of the present invention is a dehydrogenation reaction in which a hydroxyl group in the starting material cyclopentanol is converted into a carbonyl group in the target cyclopentanone.

The reaction temperature is not particularly limited, but is usually 14
0 ° C. to 450 ° C., preferably 160 ° C. to 3 ° C.
00 ° C. If the reaction temperature is excessively low, sufficient catalytic activity may not be obtained, or the starting material cyclopentanol may condense in the reaction tube. On the other hand, when the reaction temperature is excessively high, crystal growth by sintering of copper, which is a catalytically active component, is promoted, so that the selectivity of cyclopentanone is reduced and the life of the catalyst is significantly reduced.

The reaction pressure is not particularly limited, and a wide range of pressure from reduced pressure to increased pressure can be selected, but 0 to 0.3 MPa is preferable. If the reaction pressure is too high, it is disadvantageous in terms of the equilibrium of the reaction, so that a sufficiently high cyclopentanol conversion cannot be obtained.

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 catalyst bed may be either a fixed bed type or a fluidized bed type, but a fixed bed type is preferred. The reactor used is not limited by its shape or material. In the case of a batch reaction, it is a pressure-resistant reactor, and in the case of a flow reaction, one or more reactors connected in series, for example, a multitubular fixed bed. It is a flow reactor.

When this reaction is carried out by a fixed bed flow gas phase reaction,
The inner diameter of the reaction tube is not particularly limited, but is preferably 6 m
m to 100 mm, more preferably 10 mm to 70 mm. The length of the reaction tube is preferably 0.1 m to 1 m.
0 m, more preferably 0.3 m to 7 m.

Raw material cyclopentanol in reaction tube
Liquid space velocity (total flow rate of supplied raw material per hour (liquid
The value obtained by dividing the capacity (based on capacity) by the charged volume of the catalyst (based on empty cylinders).
Hereinafter, it is referred to as LHSV. ) Is not particularly limited, but usually
0.5 hr^―1~ 200hr ^―1, Preferably 1.5h
r^―1~ 50hr^―1Range. LHSV is excessive
Larger values may result in a sufficiently high cyclopentanol conversion.
Not. If the LHSV is too small, the production efficiency will decrease.
You.

The reaction product is collected by cooling, and cyclopentanone can be isolated by a conventional purification method such as distillation. The cyclopentanone thus produced is useful as a raw material for producing jasmine-based fragrances and the like.

[0031]

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. The percentages in the examples are on a molar basis unless otherwise specified.

The conversion (%) of cyclopentanol and the selectivity (%) and yield (%) of cyclopentanone, which show the reaction results in Examples and Comparative Examples, were determined by the condensate (crude) obtained by the reaction. The product was calculated by the following formula based on the composition ratio obtained by analyzing the product by gas chromatography.

Conversion of cyclopental (%) = [1-
(Flow rate (mol / min) of cyclopentanol at outlet of reaction tube) / (flow rate (mol / min) of introduced cyclopentanol)] × 100 Selectivity (%) of cyclopentanone = (Cyclo at outlet of reaction tube) Pentanone flow rate (mol / min)) ÷ [(introduced cyclopentanol flow rate (mol / min))-(cyclopentanol flow rate at reaction tube outlet (mol / min))] × 1
00 Yield (%) of cyclopentanone = (conversion rate) × (selectivity) 率 100

Example 1 Dehydrogenation of cyclopentanol
Reaction and catalyst analysis (dehydrogenation reaction) A copper-zinc catalyst (copper oxide) was placed in a stainless steel reaction tube (inner diameter 23 mm, length 400 mm) equipped with a stainless steel thermocouple protection tube having an outer diameter of 3.18 mm at the center of the cross section. 40.7 ml of 47.9% by weight, 44.0% of zinc oxide, and columnar pellets having a diameter of 6 mm and a length of 5.8 mm each containing 8.1% of graphite were charged and heated to 190 ° C. in an electric furnace. Without performing reduction treatment of the catalyst, cyclopentanol (purity 99.2%) was added to the reaction tube with LHSV =
The reactor was supplied at a rate of 1.6 hr- ^{1 and} the reaction was continuously performed for 10 hours while maintaining the outlet pressure of the reaction tube at normal pressure. The gas flowing out of the reaction tube was collected by cooling to obtain a condensate (crude product). Table 1 shows the reaction results obtained by gas chromatography analysis of the condensate collected 10 hours after the start of the continuous reaction, that is, immediately before the reaction was stopped.

(Analysis of Catalyst) The catalyst before and after use in the above-mentioned reaction is powdered, and crystals of copper oxide (before use) or copper (after use) contained in the catalyst are converted into an X-ray diffractometer ( (Manufactured by Rigaku Rotaflex). Table 1 shows the crystal grain size of copper oxide or copper calculated by the Debye-Scherrer equation based on the diffraction line width. In addition, Table 1 shows the results of measuring the specific surface area of the catalyst before and after use in the reaction by the BET method.

Example 2 Dehydrogenation of cyclopentanol
Reaction and analysis of catalyst In the same reaction tube as in Example 1, a copper-zinc catalyst (copper oxide 47.
9% by weight, zinc oxide 44.0%, graphite 8.1%
(32.5 ml of a cylindrical pellet having a diameter of 3 mm and a length of 3 mm) was charged, and the reaction tube was heated to 200 ° C. in an electric furnace. Without reduction treatment of the catalyst, cyclopentanol (purity: 99.2%) was converted to LHSV = 4.8 hr ⁻¹
And the reaction was continued for 300 hours. Table 1 shows the reaction results 55 hours and 300 hours after the start of the reaction (immediately before stopping the reaction). Table 1 shows the results of analyzing the catalyst in the same manner as in Example 1.

Comparative Example 1 Reduction of Catalyst, Cyclopentano
Reaction of catalyst and analysis of catalyst (reduction of catalyst) The same reaction tube and catalyst as in Example 1 were used.
The reaction tube was heated to 140 ° C. in an electric furnace, and the gas space velocity (the value obtained by dividing the total flow rate of the supply gas per hour (based on gas volume) by the packed volume of catalyst (based on empty cylinders)) = 560 hr
^{At -1} , a mixed gas of nitrogen and hydrogen was supplied. The initial hydrogen concentration of the mixed gas was 10% by volume, and the internal temperature of the reaction tube was 200%.
The hydrogen concentration and the heating temperature were gradually increased so as not to exceed ° C. Thereafter, the catalyst was subjected to hydrogen reduction at 180 ° C. for 30 minutes by supplying only hydrogen gas.

(Dehydrogenation Reaction and Analysis of Catalyst) Next, the reaction tube was heated to 190 ° C. in an electric furnace. Cyclopentanol (purity: 99.2%) was supplied at a rate of LHSV = 1.6 hr ⁻¹ , and a continuous reaction was performed for 10 hours in the same manner as in Example 1. Table 1 shows the reaction results and catalyst analysis results 10 hours after the start of the reaction.

[0039]

[Table 1]

In Table 1, "CPL" refers to cyclopentanol and "CPN" refers to cyclopentanone. The terms "before use" and "after use" mean before and after use of the catalyst in the gas phase dehydrogenation reaction. However, “before use” in the column of Comparative Example 1 refers to a catalyst obtained by performing only the above-described hydrogen reduction treatment on the catalyst. In the column of “crystal grain size” in Table 1, the values “before use” in Examples 1 and 2 are the results of X-ray diffraction analysis of copper oxide. Further, “after use” of Example 1, Example 2 and Comparative Example 1, and “after use” of Comparative Example 1 are results of X-ray diffraction analysis of copper.

As shown in Table 1, the catalysts of Examples 1 and 2 had a copper oxide or copper crystal grain size of 0.1 before and after use.
The specific surface area is 15 m ² / g or more before and after use. In the reactions of Examples 1 and 2, the desired product cyclopentanone is stably generated over a long period of time while maintaining a high cyclopentanone selectivity. On the other hand, the catalyst of Comparative Example 1 subjected to the hydrogen reduction treatment has a smaller specific surface area and a larger crystal grain size than the catalyst of Example 1. And, the cyclopentanone selectivity of the reaction is significantly reduced.

[0042]

The method of the present invention has an effect that cyclopentanone can be industrially advantageously produced from cyclopentanol as a raw material with a high reaction selectivity and a simple process.

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Claims (2)

[Claims] 1. A method for producing cyclopentanone by subjecting cyclopentanol to a gas phase dehydrogenation reaction in the presence of a catalyst containing copper as an active ingredient, wherein the catalyst contains copper oxide or copper crystals contained therein. The particle size is 0.13 nm or less, and the specific surface area is 15 m ² /
g. A method for producing cyclopentanone, comprising using a catalyst having a weight of at least g. 2. The method for producing cyclopentanone according to claim 1, wherein a reduction treatment of the catalyst is not performed as a step before the gas phase dehydrogenation reaction.