JP2009029836A - Method for producing phenyl ester - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a phenyl ester by performing liquid-phase reaction among benzene, carboxylic acid and molecular oxygen in the presence of a specific catalyst with an industrial advantage under suppression of the elution of palladium. <P>SOLUTION: In this production method, when the phenyl ester is produced by reaction among benzene, carboxylic acid and molecular oxygen in the presence of a palladium catalyst, a cyclic hydrocarbon is allowed to coexist. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing phenyl ester in high yield by reacting benzene, carboxylic acid and molecular oxygen in the presence of a specific catalyst.

  A method for producing a phenyl ester by reacting benzene, carboxylic acid and molecular oxygen in the presence of a specific catalyst is well known, and examples examined in a gas phase or a liquid phase using a noble metal as a catalyst. It has been reported. Palladium is best known as the main catalyst, and a method of adding a metal which is not effective by itself as a promoter is also known.

  For example, as examples of supported metal catalysts, Japanese Patent Publication No. 46-33024 discloses palladium metal or a method using platinum and gold, silver, copper, iron, manganese, etc., and Japanese Patent Publication No. 48-18219 discloses palladium metal or A method using platinum and bismuth or tellurium. In Japanese Patent Publication No. 55-15455, a method using nitric acid and a compound selected from the group consisting of palladium and cadmium, zinc, uranium, tin, lead, antimony, bismuth, tellurium and thallium. Is disclosed.

  As an example using a metal compound as a catalyst, Japanese Patent Publication No. 50-34544 discloses oxides, hydroxides, acetates, nitrates and alkali metal nitrates of platinum, palladium, rhodium, ruthenium, iridium and osmium. A method using a combined catalyst, JP-A-48-4439 discloses a method using a palladium compound and nitric acid, nitrous acid or a metal salt thereof and a metal carboxylate, JP-B-2-13653 discloses a palladium acetate And a method using at least one acetate selected from the group consisting of antimony acetate, chromium, nickel, manganese and iron.

  However, in these methods, when phenyl ester is produced by reacting benzene, carboxylic acid, and molecular oxygen in the presence of a specific catalyst in the liquid phase, palladium metal is eluted into the raw material liquid, and the catalytic activity increases over time. There is a problem that it is lowered. Since palladium is an expensive noble metal, its loss is an economically large burden, and the process becomes complicated when a palladium recovery step is provided later. Furthermore, from an industrial point of view, a decrease in activity over time means that operation to compensate for this must be performed, which is a major problem.

  On the other hand, the method of using a metal salt that is soluble in the reaction solution as a catalyst requires a recovery step of the metal salt in the subsequent stage. Further, for example, in the case of a palladium compound, the palladium compound reacts as a metal as the reaction proceeds. There is a problem of precipitation in the vessel. Even in this case, the catalytic activity decreases with time, and the loss of palladium becomes an economic burden.

  JP-A-63-174950 discloses that a soluble bismuth or lead compound coexists in a reaction system in a method using palladium and bismuth or lead as a catalyst in a liquid phase reaction. According to this method, the soluble bismuth or lead compound prevents elution of the metallic bismuth or lead supported on the catalyst and suppresses the elution of palladium, which is the main catalyst. It is described that there is.

  However, the amount of soluble bismuth or lead compound added to the reaction system is large, and in the step of separating and purifying phenyl ester, a step for recovering these compounds as crystals is necessary, which makes the process complicated and impractical. .

  Therefore, an object of the present invention is to produce a phenyl ester more stably by suppressing elution of palladium when producing phenyl ester by reacting benzene, carboxylic acid and molecular oxygen in the presence of a palladium catalyst in a liquid phase. Is to provide.

  The present inventor has intensively studied in order to solve the problems of the prior art as described above. As a result, in the production of phenyl ester by reacting benzene, carboxylic acid and molecular oxygen in the presence of a palladium catalyst, at least one of alcohols, aldehydes, cyclic hydrocarbons and formic acid is used as an additive. It has been found that the coexistence suppresses the elution of palladium metal into the raw material solution and suppresses a decrease in catalyst activity over time, and thus the present invention has been completed.

  That is, the present invention is characterized in that, in the production of a phenyl ester by reacting benzene, carboxylic acid and molecular oxygen in the liquid phase in the presence of a palladium catalyst, a cyclic hydrocarbon is allowed to coexist as an additive. It is a manufacturing method of ester.

  Hereinafter, the present invention will be described in more detail.

  In the present invention, a known palladium catalyst can be used, and the main catalyst is palladium metal. Moreover, you may use it, adding a promoter to a catalyst. As the promoter, known elements can be used, and examples thereof include gold, silver, copper, iron, manganese, cadmium, zinc, uranium, tin, thallium, lead, bismuth, antimony, tellurium and the like. The ratio of palladium and their ratio may be a commonly used ratio, and is preferably 0.01 to 20, more preferably 0.02 to 10 with respect to palladium 1, but the promoter may reduce the effect of the additive. As long as it is not, it may be out of this range.

  There are no particular restrictions on the raw material of palladium used in preparing the palladium catalyst. For example, palladium metal, ammonium hexachloropalladate, potassium hexachloropalladate, sodium hexachloropalladate, ammonium tetrachloropalladate, potassium tetrachloropalladate, tetrachloropalladium. Sodium acetate, potassium tetrabromopalladate, palladium oxide, palladium chloride, palladium bromide, palladium iodide, palladium nitrate, palladium sulfate, palladium acetate, potassium dinitrosulfite palladium acid, chlorocarbonyl palladium, dinitrodiammine palladium, tetraammine palladium chloride , Tetraamminepalladium nitrate, cis-dichlorodiamine palladium, trans-dichloro Diamine palladium, dichloro (ethylenediamine) palladium, potassium tetra cyano palladium acid, palladium acetylacetonate and the like.

  The catalyst is preferably used by being supported on a carrier which is itself inert to the reaction. Examples of preferable carriers include activated carbon and silica. The amount of palladium supported when using the carrier is 0.01 to 10 wt%, preferably 0.1 to 5 wt%, based on the weight of the carrier. This range is preferable because economical and sufficient activity can be obtained.

  The method for preparing the catalyst used in the present invention is not particularly limited, and examples include conventionally known methods for supporting a catalyst component on a carrier, such as so-called impregnation method, ion exchange method, deposition method, kneading method and the like.

  When preparing by impregnation method, for example, when using a cocatalyst, the palladium raw material and the cocatalyst component raw material may be dissolved and impregnated simultaneously, and after impregnating and supporting one of the remaining raw materials, Impregnation may be carried.

  After the loading, the solvent is removed by operations such as decantation, filtration, heating or heating under reduced pressure according to a known method in the impregnation method or ion exchange method. Heating drying, drying under reduced pressure, etc. can be used for drying after removing the solvent.

  Reduction is performed after drying, but firing may be performed before that. When firing, oxygen or oxygen diluted with nitrogen, helium, argon, or the like, or air is usually used at 200 to 700 ° C.

  A known method is used for the reduction to the catalyst. For example, a gas phase reduction method using hydrogen, carbon monoxide, ethylene, methanol or the like as a reducing agent, or a liquid phase reduction method using hydrazine hydrate, formalin, formic acid or the like can be used. In the case of the gas phase reduction method, the reduction temperature is 100 to 700 ° C, preferably 200 to 600 ° C.

  When producing phenyl esters by reacting benzene, carboxylic acid, and molecular oxygen, if the cause of palladium elution is unknown, it is estimated that palladium is oxidized during the reaction, and finally eluted as palladium acetate. It seems to be.

  The action of the coexisting additive is therefore not clear, but it can also be considered to suppress the elution of palladium by maintaining palladium that is about to be oxidized during the reaction in the production of the phenyl ester in a metallic state. . Therefore, what can be used as an additive is one that can maintain palladium to be oxidized in a metallic state under the reaction conditions in which benzene, carboxylic acid, and molecular oxygen are reacted to produce phenyl ester. In the present invention, it is at least one selected from the group consisting of alcohols, aldehydes, cyclic hydrocarbons, and formic acid. Examples of alcohols include alcohols having 1 to 10 carbon atoms, and specific examples include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutanol, 1-pentanol, 2-pentanol, 3-pentanol, 2-methyl-1-butanol, 2-methyl-2-butanol, 3-methyl-1-butanol, 3-methyl-2-butanol, amyl alcohol, 1-hexanol, 2 -Hexanol, 3-hexanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol, 2,2-dimethyl-1-butanol, 3,3-dimethyl-1-butanol, 3,3-dimethyl 2-butanol, 1-hexanol, cyclohexanol, benzyl alcohol, heptanol, 1-octa Lumpur, 2-methylheptanol, 2-ethylhexanol, 1-nonanol, isononyl alcohol, 1-decanol and the like can be exemplified. Of these ethanol is preferred. Aldehydes are aldehydes having 1 to 10 carbon atoms, and are formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, isobutyraldehyde, 2-methylbutyraldehyde, valeraldehyde, isovaleraldehyde, pivalaldehyde, and capronaldehyde. , 2-ethylbutyraldehyde, 2-methyl-n-valeraldehyde, heptylaldehyde, benzaldehyde, salicylaldehyde, caprylaldehyde, 2-ethylhexylaldehyde, tolylaldehyde, phthalaldehyde, pelargonaldehyde, caprinaldehyde, etc. But acetaldehyde is preferred. Specific examples of cyclic hydrocarbons include cyclohexane, cyclohexene, cyclohexadiene, and tetrahydronaphthalene, and among them, cyclohexene is preferable.

  Since the amount of the additive varies depending on the effect of the additive and the type of the phenyl ester produced, the range cannot be generally limited. However, the molar ratio with respect to benzene 1 is preferably 0.00001-10. is there.

  The carboxylic acid used in the present invention is a carboxylic acid having 10 or less carbon atoms, and is preferably a lower carboxylic acid such as acetic acid or propionic acid.

  The ratio of benzene and carboxylic acid can be changed freely. A preferable benzene / carboxylic acid ratio may be within a range of 1 / 0.1 to 1/100 in terms of molar ratio.

  In the production method of the present invention, the reaction with benzene, carboxylic acid and molecular oxygen is carried out in the liquid phase in the presence of a catalyst. In the present invention, the liquid phase means that the surface of the catalyst is covered with the raw material liquid, and the reaction method is not particularly limited. For example, a fixed bed flow reactor, a fluid bed flow reactor, a batch reactor, a suspension bed, or the like can be used.

The amount of catalyst used varies depending on the reaction method and cannot be defined uniformly. However, in consideration of economy, for example, in the case of a fixed bed, the unit catalyst volume, the total supply amount of benzene and carboxylic acid per unit time (LHSV) The catalyst amount is preferably in the range of 0.1 to 50 h ⁻¹ , preferably 0.1 to 30 h ^{−1. In} the case of a suspended bed, the catalyst concentration is 0.05 to 30 relative to the raw material. A range of% by weight is preferred.

  The reaction temperature is 100 to 300 ° C, preferably 100 to 250 ° C.

  The reaction pressure may be 10 to 100 atm, as long as the catalyst surface is covered with the raw material liquid at the reaction temperature.

  In the present invention, oxygen is used as the oxidizing agent. Oxygen may be diluted with an inert gas such as nitrogen, helium, or argon, and air can also be used. The optimum amount of oxygen to be supplied varies depending on the reaction temperature, the amount of catalyst, etc., but it is sufficient that the gas composition at the position passing through the catalyst is below the explosion range.

  The reaction time varies depending on the method of setting the reaction temperature, pressure, amount of catalyst, etc., or the reaction method, so it is difficult to determine the range in general. 0.5 hour or more is required. In the continuous reaction using a suspended bed or the fixed bed continuous reaction, the residence time may be 0.03 to 10 hours.

  In the presence of a palladium catalyst, benzene, carboxylic acid, and molecular oxygen are reacted in the liquid phase to produce phenyl esters. By making cyclic hydrocarbons coexist as additives, palladium metal is eluted in the raw material liquid. This can be suppressed, and a decrease in catalyst activity over time can be suppressed.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

Preparation of catalyst 1
3.55 g of tartaric acid was dissolved in 16 g of distilled water, and 0.49 g of antimony oxide was added and dissolved therein. Subsequently, 7.27 g of an aqueous 8.26 wt% palladium nitrate solution was added. The aqueous solution was impregnated with 20 g of silica (Carteact Q-30 manufactured by Fuji Silysia). Then, it dried under reduced pressure at 50 degreeC, vacuum-dried at 100 degreeC for 3 hours, air baking at 400 degreeC for 5 hours, and hydrogen reduction at 400 degreeC for 5 hours. The amount of palladium supported on silica was 3 wt%, and the amount of antimony added to palladium was 3/5 in molar ratio.

Preparation of catalyst 2
7.27 g of an 8.26 wt% palladium nitrate aqueous solution was weighed and 0.13 g of telluric acid and distilled water were added to make a total volume of 21 ml. The aqueous solution was impregnated with 20 g of silica (Carteact Q-30 manufactured by Fuji Silysia). Then, it dried under reduced pressure at 50 degreeC, vacuum-dried at 100 degreeC for 3 hours, air baking at 400 degreeC for 5 hours, and hydrogen reduction at 400 degreeC for 5 hours. The amount of palladium supported on silica was 3 wt%, and the amount of tellurium added to palladium was 1/10 in molar ratio.

Example 1
10 ml of the catalyst prepared by the method of Catalyst Preparation 1 was packed in a reaction tube made of SUS316 having an inner diameter of 13 mm, an equimolar mixture of benzene and acetic acid at a catalyst layer temperature of 190 ° C. and a reaction pressure of 20 atm, 2.2 g / min, oxygen Was continuously supplied at 27 Nml / min and nitrogen was supplied at 183 Nml / min. In addition, the raw material liquid to be supplied was prepared by adjusting methanol so that the mixing ratio of benzene, acetic acid and methanol was 49: 49: 2.

  The reaction product was collected at 5 hours and 50 hours after the start of the reaction, separated into a gas component and a liquid component, and then analyzed by gas chromatography. The ratio of the amount of phenyl acetate produced at 50 hours to the amount of phenyl acetate produced at 5 hours (50 hr / 5 hr) was used as an index of the effect of the additive.

  The amount of palladium eluted in the reaction solution from the start of the reaction to 50 hours was measured by atomic absorption spectrometry. The amount of palladium eluted was expressed as a percentage of the total amount of palladium supported on the catalyst.

  These results are summarized in Table 1.

Examples 2-6
The reaction was conducted in the same manner as in Example 1 except that ethanol, 2-propanol, 2-butanol, formic acid, and cyclohexane were used as additives. The results are summarized in Table 1.

Example 7
The reaction was carried out in the same manner as in Example 1 except that ethanol was used as an additive and the supply amount thereof was adjusted so that the mixing ratio of benzene, acetic acid and ethanol was 45:45:10 in molar ratio. It was. The results are summarized in Table 1.

Example 8
Example 1 except that cyclohexene was used as an additive and the supply amount thereof was adjusted so that the mixing ratio of benzene, acetic acid and cyclohexene was 49.925: 49.925: 0.15 in molar ratio. The reaction was conducted in the same manner. The results are summarized in Table 1.

Example 9
Example 1 except that cyclohexene was used as an additive and the supply amount thereof was adjusted so that the mixing ratio of benzene, acetic acid and cyclohexene was 49.75: 49.75: 0.5 in molar ratio. The reaction was conducted in the same manner. The results are summarized in Table 1.

Comparative Example 1
The reaction was performed in the same manner as in Example 1 except that the additive was not supplied. The results are summarized in Table 1.

実施例１０
触媒の調製２の方法で調製した触媒を用いたこと、添加剤としてエタノールを使用したこと及びその供給量をベンゼン、酢酸及びエタノールの混合割合が、モル比で４９：４９：２となるように調整したこと以外は実施例１と同様にして反応した。その結果を表２にまとめた。

Example 10
The catalyst prepared by the method of catalyst preparation 2 was used, ethanol was used as an additive, and the supply amount thereof was such that the mixing ratio of benzene, acetic acid and ethanol was 49: 49: 2. It reacted like Example 1 except having adjusted. The results are summarized in Table 2.

Example 11
The reaction was conducted in the same manner as in Example 10 except that the supply amount was adjusted so that the mixing ratio of benzene, acetic acid and ethanol was 45:45:10 in terms of molar ratio. The results are summarized in Table 2.

Example 12
Example 10 except that cyclohexene was used as an additive and the supply amount thereof was adjusted so that the mixing ratio of benzene, acetic acid and cyclohexene was 49.875: 49.875: 0.25 in molar ratio. It reacted in the same way. The results are summarized in Table 2.

Example 13
Example 10 except that cyclohexene was used as an additive and the supply amount thereof was adjusted so that the mixing ratio of benzene, acetic acid and cyclohexene was 49.75: 49.75: 0.5 in terms of molar ratio. The reaction was conducted in the same manner. The results are summarized in Table 2.

Example 14
Example 10 except that acetaldehyde was used as an additive and the supply amount thereof was adjusted so that the mixing ratio of benzene, acetic acid and acetaldehyde was 49.75: 49.75: 0.5 in molar ratio. The reaction was conducted in the same manner. The results are summarized in Table 2.

Comparative Example 2
The reaction was carried out in the same manner as in Example 10 except that the additive was not supplied. The results are summarized in Table 2.

Claims (2)

A method for producing a phenyl ester, characterized in that, in the production of a phenyl ester by reacting benzene, a carboxylic acid and molecular oxygen in the liquid phase in the presence of a palladium catalyst, a cyclic hydrocarbon is used as an additive. The method for producing a phenyl ester according to claim 1, wherein the cyclic hydrocarbon is cyclohexane, cyclohexene, cyclohexadiene or tetrahydronaphthalene.