JPH0152373B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing cyclopentanone,
More specifically, the present invention relates to a method for producing cyclopentanone by contacting cyclopentanol with a palladium catalyst to cause a dehydrogenation reaction. Cyclopentanone is a substance useful as a solvent, an intermediate for fragrances, chemicals, etc., and its mass production has recently been desired. As a method for producing such cyclopentanone, a cyclopentanol dehydrogenation method using a zinc-copper catalyst has been known (for example, U.S. Pat. No. 2,377,412, Japanese Patent Publication No. 53
−3379 etc.). However, this method does not necessarily provide a sufficient yield per space and time, and the activity of the catalyst deteriorates in a relatively short period of time, so it is difficult to say that it is a method suitable for industrial production. On the other hand, a method of dehydrogenating secondary alcohols such as isopropanol, benzyl alcohol, cyclohexanol, etc. using a platinum metal element is also known. For example, British Patent No. 823514 describes a method for dehydrogenating a secondary alcohol with a platinum metal element supported on a non-acidic carrier, and a specific example of this is an experiment in which isopropanol is treated with platinum, ruthenium, palladium, or rhodium. An example is shown. According to the description, platinum and ruthenium, which are the same platinum metal elements, have extremely high activity, while rhodium has low activity.
Palladium has been shown to be even less active. Also React.Kinet.Catal.Letter1(2)121 (1974) and
Kem. Kozl. 44 (1-2) 35 (1975) reports that when cyclohexanol is treated with platinum, phenol is directly produced without passing through cyclohexanone, and at the same time cyclohexene, benzene, etc. are produced as by-products. This statement is inconsistent with the statement in the British patent, and there has been no clear knowledge regarding the dehydrogenation of alicyclic alcohols by platinum metal elements. Therefore, the present inventors conducted intensive studies to develop an efficient synthesis method for cyclopentanone based on the knowledge of the prior art, and found that cyclopentanol has a low activity when dehydrogenating isopropanol. The present inventors discovered that palladium, which had not been previously demonstrated, had extremely excellent performance, and completed the present invention. Thus, the present invention provides a method for producing cyclopentanone, which comprises dehydrogenating cyclopentanol by contacting it with palladium metal or a palladium compound. The purpose of the present invention is to industrially advantageously produce cyclopentanone, and by a simple unit operation of contacting the raw material cyclopentanol with a palladium catalyst, it is possible to produce cyclopentanone in a high space-time yield and in a high yield. This is a method for producing cyclopentanone that exhibits single-stream yield, high selectivity, and excellent catalyst durability. The cyclopentanol used as a raw material in the present invention may be obtained by any manufacturing method, and does not necessarily have to be of high purity as long as it does not essentially impede the effects of the present invention. do not have. Specific examples of such industrial methods for obtaining cyclopentanol include a cyclopentene hydration method, a cyclopentane liquid phase air oxidation method, and cyclopentanol present in a by-product fraction during the production of adipic acid. , and are used after being separated and purified as necessary. At this time, water, alcohol, ketone, ether, ester, hydrocarbon, etc. may coexist with cyclopentanol, and if a compound that is easily dehydrogenated such as alcohol is included, dehydrogenation reaction will occur concurrently, and ketone When containing compounds that are easily hydrogenated, such as unsaturated hydrocarbons or unsaturated hydrocarbons, hydrogenation reactions occur simultaneously. The catalyst used in the present invention is palladium metal or a palladium compound, and can be prepared according to a known catalyst preparation method. Such a catalyst can be used alone, but industrially it is advantageous to use a catalyst supported on a carrier material in order to produce a large amount of cyclopentanone with a small amount of palladium. Support materials include, for example, silica, silicates,
Examples include carbonaceous materials, carbonates, magnesia, alumina, aluminates, titania, titanates, diatomaceous earth, zirconia, silica alumina and its metal salts, pumice, and the like. When carrying ions such as palladium ions, palladium ammine complex ions, and other complex ions by ion exchange method or ligand exchange method, the carrier must have acid sites or coordination sites that can exchange and adsorb these ions. It is preferable to have. The amount of palladium supported depends on the desired reaction rate,
It can be selected depending on the purpose, depending on the reaction temperature, reactor size, product distribution, etc., but it is economical to use about 0.1 to 10% by weight. Examples of methods for supporting the carrier include ion exchange method, ligand exchange method, impregnation method, deposition method, coating method, coprecipitation method, kneading method, etc. Preferably, palladium atoms are supported by a method of impregnating and coating, and exchange-supporting near the surface of the carrier in combination with a method of impregnation coating is also a preferable method for efficiently utilizing palladium atoms. Palladium may be in any existing state before the reaction, such as an ionic state, a cluster state, a metallic state, an oxide, a complex compound, etc., but it is preferable to keep it in a highly dispersed state. . It is also possible to apply not only palladium but also known methods for surface modification by coexisting with compounds known as promoters, such as alkali metals, alkaline earth metals, etc., or by coexisting with compounds that do not poison the catalyst. Furthermore, if the carrier is too acidic, the carrier can be neutralized after supporting palladium. The catalyst may be in any known shape such as a powder or a molded product. The catalyst can be used as it is, but prior to the reaction, it may be subjected to heat treatment, oxidation treatment, reduction treatment, etc. alone or in combination by known methods. The reaction can be applied in either liquid phase or gas phase, but industrially it is usually carried out in gas phase and used as a fixed bed or fluidized bed, and the fixed bed method is easier and more convenient to operate. It is. The reaction temperature can be selected over a wide range depending on the reaction pressure and reaction time, but is preferably 100 to 450°C, preferably 150 to 400°C.
It is ℃. The reaction pressure can be selected from reduced pressure to high pressure, but it is economical to carry out the reaction at 0.2 to 5 kg/cm ² .
The reaction time is not necessarily constant depending on the reaction type, catalyst production method, amount supported, etc., but when using a fixed bed flow gas phase reactor with 0.5% by weight supported catalyst, it is preferably 0.1 to 100 seconds. It is best to choose a time between 0.5 seconds and 20 seconds. Further, the raw material may be diluted with an inert gas such as nitrogen or steam before being supplied. Thus, according to the present invention, cyclopentanone can be produced from cyclopentanol in high yield, high selectivity, and with good durability. The present invention will be described in more detail with reference to examples below, but the present invention is not limited to the following examples. Note that parts and percentages in the examples are based on weight unless otherwise specified, and the products in the examples were analyzed using both gas chromatography and mass spectrometry. Example 1 10 to 20 meshes of silica gel (manufactured by Davison,
Davison 1D gel) 500g 10% ammonia water 1500
After degassing with an aspirator, soak in the liquid for one day. After washing with water and drying, the sample was immersed in an aqueous solution of 11.5 parts of amminepalladium chloride [Pd(NH ₃ ) ₄ ]Cl ₂ dissolved in 1300 parts of water for 1 day for ion exchange.
After washing with water and drying, it was fired in a Matsufuru furnace at 300°C for 2 hours. This catalyst contains 1% palladium. Next, 10ml of the catalyst was filled into a stainless steel reactor with an inner diameter of 20mmφ, and hydrogen reduction was performed so that the catalyst bed temperature was 250°C, and then cyclopentanol was supplied in a gas phase for a predetermined contact time. After the reaction was carried out at a predetermined temperature under normal pressure and the activity became constant, the product was analyzed and the yield and selectivity were determined. The results are shown in Table 1.

[Table] Example 2 100 parts of the catalyst after the heat treatment in Example 1, 1 part of sodium carbonate, and 150 parts of water were mixed, degassed under reduced pressure, and then immersed for one day and night to evaporate to dryness. Next, 10 ml of this catalyst was filled into a stainless steel reactor with an inner diameter of 20 mmφ, and after pretreatment by supplying cyclopentanol in a gas phase instead of hydrogen reduction, the reaction pressure was controlled as in Example 1. The reaction was carried out. As a result, the yield and selectivity of cyclopentanone were as shown in Table 2. Furthermore, although the reaction of experiment number (2-2) was continued for 10 days, almost no decrease in activity was observed.

[Table] Example 3 In the same manner as in Example 2, a catalyst was prepared in which 2% palladium was ion-exchange supported on activated carbon that had been oxidized to create proton acid sites. When the reaction was carried out in the same manner as in Example 2, the cyclopentanone yield and selectivity at 5 hours after the start of the reaction were each 60.8.
%, 85.7%.

Claims (1)

[Claims] 1. A method for producing cyclopentanone, which comprises dehydrogenating cyclopentanol by contacting it with a palladium catalyst.