JP4193904B2 - Method for producing benzyl acetate - Google Patents

Description

  The present invention relates to a method for producing benzyl acetate by reacting toluene, acetic acid and oxygen in a liquid phase. Benzyl acetate itself is useful as a solvent and a fragrance. Furthermore, benzyl alcohol obtained by hydrolyzing benzyl acetate is a solvent with excellent solubility and non-toxicity, so it can be used as a pharmaceutical additive, agricultural chemical, pharmaceutical, etc. It is an extremely important compound as an intermediate.

  Conventionally, it is known that palladium is useful as a catalyst in a method for producing benzyl acetate by reacting toluene, acetic acid and oxygen in a liquid phase, and a method for synthesizing benzyl acetate in a gas phase has been reported.

  For example, Japanese Patent Publication No. 44-29046 and Japanese Patent Publication No. 51-25438 disclose methods using a catalyst in which palladium and an alkali metal or alkaline earth metal acetate are supported on alumina.

  Japanese Patent Application Laid-Open No. 47-18843 discloses a catalyst in which palladium, bismuth and an alkali metal are supported on silica.

  Japanese Patent Publication No. 56-21463 discloses a catalyst in which palladium, antimony and zinc acetate or potassium acetate are supported on silica.

  Further, Japanese Examined Patent Publication No. 56-23417 discloses a catalyst in which palladium, an oxide of vanadium and an alkali metal hydroxide or an alkali metal acetate are supported on alumina.

  When these palladium-based catalysts are used in the gas phase, favorable results are observed in the formation activity and selectivity of benzyl acetate at the initial stage of the reaction, but the activity rapidly increases in a short time. There was a problem that it could not be an industrial catalyst.

  On the other hand, it is also known that benzyl acetate can be synthesized in the liquid phase.

  For example, “The Journal of Organic Chemistry” (J. Org. Chem), (33), 4123 (1968) uses palladium acetate as a catalyst and oxidizes toluene in acetic acid with air. A method for synthesizing benzyl acetate has been reported.

  However, this method has the problem that although palladium acetate used as a catalyst is uniformly dissolved immediately after the start of the reaction, the catalyst activity is lost because it precipitates as metallic palladium as the reaction proceeds. It is hard to say that it is an industrial method of benzyl acetate.

  A method for synthesizing benzyl acetate in a liquid phase using various supported catalysts has also been reported.

  For example, Japanese Patent Publication No. 42-13081 discloses a method of synthesizing benzyl acetate in a liquid phase using a catalyst in which palladium is supported on alumina and an alkali metal acetate. Although this method is preferable because both the activity of the catalyst and the selectivity of benzyl acetate are high, a large amount of alkali metal acetate is required, which is not practical in the industry.

  JP-A-52-151135 and JP-A-52-151136 disclose a catalyst in which one selected from bismuth, molybdenum, manganese, vanadium and tungsten supported on silica is combined with palladium. . Although these catalysts are characterized by high activity per catalyst weight and high selectivity, they have low productivity per reaction vessel and are not industrially satisfactory.

  Japanese Patent Publication No. 50-28947 reports a catalyst comprising palladium and one component selected from bismuth, cobalt and iron supported on silica, but its catalytic activity is insufficient from an industrial viewpoint. In addition, the fact that a large amount of potassium acetate is used is not preferred industrially.

  Japanese Examined Patent Publication No. 52-16101 discloses a method using a catalyst in which palladium, bismuth and chromium are supported on silica and an alkali metal acetate. Although this catalyst has a sufficiently high activity per unit catalyst weight and a considerably high benzyl acetate selectivity, the activity per reactor is insufficient in view of industrialization, and sodium acetate is added to the reaction system to separate the catalyst. Recycling is complicated and not industrially preferable.

Furthermore, Japanese Patent Application Laid-Open No. 63-174950 discloses a method using both a catalyst in which palladium and bismuth or lead are supported on silica and a bismuth compound or lead compound soluble in the reaction system. The soluble bismuth or lead compound in this method prevents elution of the supported metallic bismuth or lead, and therefore, elution of palladium, which is the main active species, is prevented, and is described as effective in maintaining the activity. ing. That is, this catalyst is a catalyst in which palladium, which is the main active species, elutes into the reaction solution when these soluble compounds are not present. On the other hand, in the process of separating and purifying the produced benzyl acetate, it is described that the bismuth compound or lead compound dissolved in the reaction system in order to maintain the catalyst life can be recovered as crystals and reused in the reaction. In the process of continuously producing liquid benzyl acetate, handling solid crystals is extremely complicated industrially and not practical.

  As described above, conventional catalysts are particularly insufficient in terms of industrial productivity, and separation and recycling are complicated because alkali metal salts and cocatalysts soluble in the reaction system are added. There were problems such as being unfavorable industrially.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an industrially useful method for producing benzyl acetate using a highly active and highly selective catalyst that solves the above problems. That is.

  As a result of intensive studies to solve the above problems, the inventors of the present invention have made a specific alloy composed of palladium and bismuth into silica in a process for producing benzyl acetate by reacting toluene with acetic acid and oxygen in a liquid phase. It has been found that the use of a supported catalyst results in a catalyst having high benzyl acetate production activity and selectivity and a long duration of catalytic activity, and the present invention has been completed.

  That is, the present invention is a method for producing benzyl acetate by reacting toluene, acetic acid and oxygen in a liquid phase, and an alloy consisting of palladium and bismuth and having palladium / bismuth = 2.5 to 3 (atomic ratio) is supported on silica. And palladium supported on silica is substantially an alloy composed of palladium and bismuth, and the alloy composed of palladium and bismuth does not adsorb carbon monoxide, A method for producing benzyl acetate, which exhibits a predetermined X-ray diffraction pattern.

  The present invention will be described in detail below.

  In the present invention, in a method for producing benzyl acetate by reacting toluene with acetic acid and oxygen in a liquid phase, an alloy composed of palladium and bismuth and having palladium / bismuth = 2.5 to 3 (atomic ratio) is supported on silica. Catalyst is used.

There is no restriction | limiting in particular in the silica used for the catalyst of this invention, What was prepared by what kind of raw material and manufacturing method can be used. If the physical properties are strong, a BET specific surface area of 10 m ² / g or more and a pore volume of 0.2 cc / g or more are preferable.

  There is no restriction | limiting in particular in the shape of a catalyst, A powdered thing or a molded article can be used according to reaction mode. For suspension beds, powders or granules are preferably used, and for fixed beds, tablet compression products, spherical or rod-like extrusion products, and the like are preferably used.

  In preparing the catalyst used in the present invention, the palladium and bismuth raw materials used are not particularly limited as long as they finally form an alloy of palladium and bismuth.

  Specifically, palladium raw materials include palladium metal, ammonium hexachloropalladate, potassium hexachloropalladate, sodium hexachloropalladate, ammonium tetrachloropalladate, potassium tetrachloropalladate, sodium tetrachloropalladate, tetrabromopalladium. Potassium oxide, 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, tetraammine palladium nitrate, cis-dichlorodiammine palladium, trans-dichlorodiammine palladium Examples include dichloro (ethylenediamine) palladium, potassium tetracyanopalladate, and the like. Examples of bismuth raw materials include bismuth metal, bismuth chloride, bismuth nitrate, bismuth oxychloride, bismuth acetate, bismuth oxyacetate, and bismuth oxide. it can.

  The amount of the metal supported on the catalyst is usually 0.1 to 10% by weight based on the total weight of the catalyst including silica as an alloy composed of palladium and bismuth and having palladium / bismuth = 2.5 to 3 (atomic ratio). This atomic ratio is only the atomic ratio of palladium and bismuth forming an alloy.

  In the present invention, even if there is an excess of bismuth not forming an alloy in the catalyst, it is not excluded, but palladium supported on silica is an alloy substantially composed of palladium and bismuth. It is necessary to become.

  Whether palladium supported on silica is an alloy substantially composed of palladium and bismuth can be determined by measuring the amount of carbon monoxide adsorbed on the catalyst. This is because carbon monoxide is not adsorbed on an alloy composed of palladium and bismuth. On the other hand, when an alloy is not formed and palladium is present alone, palladium adsorbs carbon monoxide, so that it can be easily distinguished from an alloy.

  An alloy composed of palladium and bismuth in the present invention and having palladium / bismuth = 2.5 to 3 (atomic ratio) exhibits a characteristic X-ray diffraction pattern shown in Table 1 when 2θ is 30 to 80 °. Show.

この合金は、窒素中４００℃又は空気中２００℃で加熱してもＸ線回折パターンは変化しない。なお、合金の粒子径が小さくてＸ線回折パターンに解析ピークが明瞭には確認できない場合には、高分解能の電子顕微鏡と電子線回折若しくは特性Ｘ線測定を組み合わせた解析により、本発明の触媒かどうか判断することができる。

This alloy does not change its X-ray diffraction pattern when heated at 400 ° C. in nitrogen or 200 ° C. in air. When the particle size of the alloy is small and the analysis peak cannot be clearly confirmed in the X-ray diffraction pattern, the catalyst of the present invention is analyzed by analysis combining a high-resolution electron microscope and electron beam diffraction or characteristic X-ray measurement. Can be determined.

  The raw material of palladium and bismuth in the case of preparing the catalyst which supported the alloy which consists of palladium and bismuth as used in the present invention, and palladium / bismuth = 2.5-3 (atomic ratio) was supported on silica is supported on silica. The method is not particularly limited as long as palladium and bismuth form an alloy, and can be supported by a known method. Specifically, for example, it can be prepared by a precipitation method, an ion exchange method, an impregnation method, a deposition method, a kneading method, or the like.

  When preparing by the impregnation method, there is no particular limitation as long as an alloy of palladium and bismuth is finally formed, and the palladium raw material and the bismuth raw material may be impregnated and supported at the same time, or after impregnating and supporting one of them. The remaining raw materials may be impregnated and supported. In order to form an alloy of palladium and bismuth more uniformly, it is preferable to impregnate and support at the same time. Specifically, the simplest preparation method is exemplified by dissolving a raw material of palladium and bismuth in an appropriate solvent, mixing this with silica, and allowing to stand for a predetermined time if necessary, followed by drying [at this time, palladium and Bismuth raw material salt is preferably mixed at palladium / bismuth = 2.5-3 (atomic ratio)], and the obtained catalyst precursor is reduced in hydrogen or an inert gas containing hydrogen. The catalyst used in the invention can be obtained. In addition, you may bake in oxygen atmosphere before the reduction process with hydrogen.

  The temperature of the reduction treatment is usually 100 to 700 ° C, preferably 200 to 500 ° C. As a reducing agent for the reduction treatment, gases such as hydrogen, carbon monoxide, ethylene, alcohol, hydrazine hydrate, etc. are used, and an alloy catalyst can be obtained by reduction treatment in the gas phase or liquid phase. it can.

  When firing is performed before the reduction treatment, the firing may be performed usually at 200 to 700 ° C. in an atmosphere of oxygen or oxygen diluted with nitrogen, helium, argon, or the like, or air.

  The raw materials toluene and acetic acid used in the present invention can be produced by any method. For example, toluene can be used that is separated from petroleum fraction, one separated from cracked oil obtained by cracking petroleum fraction, etc., and acetic acid is produced by oxidation of acetaldehyde, Any of those produced by oxidation of hydrocarbons, those by-produced during the production of peracetic acid, those synthesized from methanol and carbon monoxide, and the like can be used.

  As for the mixing ratio of toluene and acetic acid, the reaction can be carried out at an arbitrary mixing ratio in the range of 0.1 to 100 (atomic ratio), preferably 0.2 to 40 (atomic ratio) of acetic acid based on toluene. it can.

  In the present invention, in order to suppress deterioration of the catalyst, the reaction may be carried out by dissolving a soluble compound of bismuth in toluene and / or acetic acid.

  In this case, the amount of the soluble compound of bismuth dissolved in toluene and / or acetic acid is preferably within the range of the following formula (1).

本発明において使用する触媒は、本反応系では安定であるため、特にビスマスの可溶性物質を共存させる必要はないが、共存させる場合でも、上記の範囲内で十分である。この範囲を著しく超えると、生成物のベンジルアセテートを精製する工程で、ビスマス化合物が析出し閉塞の原因となる場合がある。

Since the catalyst used in the present invention is stable in the present reaction system, it is not necessary to coexist a bismuth soluble substance, but even in the case of coexistence, the above range is sufficient. If this range is significantly exceeded, the bismuth compound may precipitate in the process of purifying the product benzyl acetate and cause clogging.

  Soluble compounds of bismuth are not particularly limited, but bismuth nitrate, bismuth oxide, bismuth oxyacetate, bismuth hydroxide, bismuth chloride, bismuth oxychloride, basic bismuth carbonate, bismuth acetate, bismuth oxalate, trimethyl bismuth Etc. are exemplified.

  In the present invention, since the reaction is carried out in the liquid phase, the reaction method is not particularly limited as long as the surface of the catalyst is covered with the raw material liquid. It can also be implemented with a formula.

The amount of catalyst to be used varies depending on the reaction method and cannot be defined uniformly. However, in the case of a fixed bed, the unit catalyst volume and the total supply amount of toluene and acetic acid per unit time (LHSV) are taken into account when considering the economy. , the range of 0.1～50H ^-1, more preferably, the catalyst amount is preferably a 0.1～30H ^-1, in the case of a suspended bed, the concentration of catalyst is 0.1 relative to the starting material A range of ˜30% by weight is good.

In the method of the present invention, from the industrial viewpoint, in order to maintain the catalyst life and selectivity while maintaining the catalyst life, the oxygen partial pressure in the gas phase portion in the reactor is 0.1 to 2 kg. / Cm ² is preferably controlled in the range. If it is less than 0.1 kg / cm ² , industrially sufficient activity cannot be obtained, and if it exceeds ² kg / cm ² , the elution of palladium increases and the activity may be significantly reduced. Moreover, the supply amount of oxygen is preferably 0.5 to 4.5 mol / h with respect to 1 liter of catalyst volume. The reactor in the present invention refers to a tank, tower or tube provided for reacting raw materials toluene, acetic acid and oxygen with the catalyst of the present invention to synthesize benzyl acetate. Examples include a reaction tank in a suspension bed, a catalyst packed tower in a fixed bed, or a multitubular reaction tube.

Reaction by the method of this invention is normally implemented under a heating and pressurization. The reaction temperature is usually 80 to 230 ° C, preferably 120 to 200 ° C. Even higher than this will only increase the progress of side reactions, and lowering this will be disadvantageous in terms of reaction rate. Moreover, the pressure should just maintain the catalyst surface in a liquid phase at reaction temperature, and 3-100 kg / cm < ² > G normally, Preferably 4-50 kg / cm < ² > G is chosen. In the method of the present invention, the desired reaction sufficiently proceeds within this range, so that a high pressure exceeding this is unnecessary.

In the method of the present invention, molecular oxygen is used as an oxidizing agent. Oxygen may be diluted with an inert gas such as nitrogen, or even air. 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 point where the catalyst has passed is below the explosion range. The unit catalyst amount and the oxygen supply amount (GHSV) per unit time are preferably 5000 h ⁻¹ or less in terms of 0 ° C. and 1 atm.

  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. However, it is usually 0 in the batch type or the semi-batch type in the suspension bed. .5 hours or more are required, and preferably 1 to 10 hours.

  In a continuous reaction or a fixed bed flow reaction using a suspension bed, the residence time is usually 0.03 to 10 hours.

  According to the present invention, in a method for producing industrially useful benzyl acetate by reacting toluene with acetic acid and oxygen in a liquid phase, a catalyst in which an alloy of palladium and bismuth having a specific composition is supported on silica is used. Benzyl acetate can be produced with high activity, high selectivity and long-lasting activity.

  Further, by controlling the oxygen partial pressure of the gas phase portion in the reaction system to a specific range, and furthermore, by controlling the supply amount of oxygen supplied to the catalyst to a specific range, the industrially satisfactory activity, The synthesis of benzyl acetate can be continued for a long time while maintaining the selectivity.

  Hereinafter, this reaction will be described in more detail with reference to Examples, but it goes without saying that this reaction is not limited to these Examples.

Example 1
2.00 g (11.28 mol) of palladium chloride (manufactured by Wako Pure Chemical Industries, Ltd.) and 1.18 g (3.75 mmol) of bismuth chloride (manufactured by Wako Pure Chemical Industries, Ltd.) were weighed in a 200 ml round bottom flask, 43 ml of hydrochloric acid was added and stirred at room temperature until the palladium chloride and bismuth chloride were completely dissolved. The atomic ratio of charged palladium to bismuth was 3.0.

Next, 40 g of silica dried at 180 ° C. for 2 hours in a dryer (manufactured by Fuji Silysia Co., CARIACT-Q30, BET specific surface area: 100 m ² / g, pore volume: 1.05 cc / g, spherical diameter of 3 mm) In addition, it was impregnated with stirring until the liquid was completely absorbed by the silica.

  After the impregnation, water was removed under reduced pressure using a rotary evaporator.

  The catalyst precursor thus obtained was put into a tubular heat treatment tube and subjected to reduction treatment at 400 ° C. for 5 hours while flowing hydrogen at 50 ml / min.

  The catalyst after the reduction treatment was repeatedly washed with ion-exchanged water until no chlorine ions were detected in the washing water by the mercuric thiocyanate method.

  After washing, the catalyst was obtained by drying at 110 ° C. for 3 hours in a dryer.

  When the catalyst thus obtained was analyzed by an X-ray diffractometer, it was found that an alloy of palladium / bismuth = 3 (atomic ratio) was formed as shown in FIG.

10 cc of this catalyst and 10 cc of glass beads having a diameter of 1 mm are mixed and packed in a reaction tube made of SUS316 having an inner diameter of 13 mm. The reaction temperature is 150 ° C., the reaction pressure is 4 kg / cm ² G, toluene is 19.5 g / h, and acetic acid is 80 Reaction was performed by continuously supplying 0.5 g / h, oxygen at 21 Nml / min, and nitrogen at 79 Nml / min.

  After separating the reaction product into a liquid and a gas, each of the liquid component and the gas component was analyzed by gas chromatography.

  The space-time yield of benzyl acetate at this time (the amount of benzyl acetate produced per unit catalyst volume per unit time: STY) was 165 g / h / L at the 5th hour from the start of the reaction, and the selectivity was 98% based on acetic acid. It was.

  Moreover, it was about 1000 hours when the time until the benzyl acetate STY was halved was calculated from the general formula of catalyst deterioration shown in the following formula (2).

Ln (r / r0) = − kt (2)
(In the formula, r represents benzyl acetate STY at time t, r0 represents initial benzyl acetate STY, and k represents a catalyst deterioration constant.)
Table 2 shows the CO adsorption amount of this catalyst and the Pd elution rate after 50 hours from the start of the reaction.

比較例１
塩化パラジウム（和光純薬工業社製）２．００ｇ（１１．２８ｍｍｏｌ）と塩化ビスマス（和光純薬工業社製）３．５６ｇ（１１．２８ｍｍｏｌ）を２００ｍｌの丸底フラスコに秤取り、１２規定の塩酸４３ｍｌを加え塩化パラジウム及び塩化ビスマスが完全に溶解するまで室温で攪拌した。

Comparative Example 1
2.00 g (11.28 mmol) of palladium chloride (manufactured by Wako Pure Chemical Industries, Ltd.) and 3.56 g (11.28 mmol) of bismuth chloride (manufactured by Wako Pure Chemical Industries, Ltd.) were weighed in a 200 ml round bottom flask, 43 ml of hydrochloric acid was added and stirred at room temperature until the palladium chloride and bismuth chloride were completely dissolved.

Next, 40 g of silica dried at 180 ° C. for 2 hours in a dryer (manufactured by Fuji Silysia Co., CARIACT-Q30, BET specific surface area: 100 m ² / g, pore volume: 1.05 cc / g, spherical diameter of 3 mm) In addition, it was impregnated with stirring until the liquid was completely absorbed by the silica.

  After the impregnation, water was removed under reduced pressure using a rotary evaporator.

  The catalyst precursor thus obtained was put into a tubular heat treatment tube and subjected to reduction treatment at 400 ° C. for 5 hours while flowing hydrogen at 50 ml / min.

  The catalyst after the reduction treatment was repeatedly washed with ion-exchanged water until no chlorine ions were detected in the washing water by the mercuric thiocyanate method.

  After washing, the catalyst was obtained by drying at 110 ° C. for 3 hours in a dryer.

  When the thus obtained catalyst was analyzed with an X-ray diffractometer, it was found that the catalyst was different from the catalyst of the present invention as shown in FIG.

  The reaction and analysis were performed in the same manner as in Example 1 except that this catalyst was used. The results are also shown in Table 2.

Comparative Example 2
43 ml of 7% nitric acid aqueous solution was added to 5.48 g (11.30 mmol) of bismuth nitrate pentahydrate (manufactured by Wako Pure Chemical Industries, Ltd.) to completely dissolve bismuth nitrate pentahydrate.

Next, 40 g of silica dried at 180 ° C. for 2 hours in a dryer (manufactured by Fuji Silysia Co., CARIACT-Q30, BET specific surface area: 100 m ² / g, pore volume: 1.05 cc / g, spherical diameter of 3 mm) In addition, it was impregnated with stirring until the liquid was completely absorbed by the silica.

  After the impregnation, water was removed under reduced pressure using a rotary evaporator.

  The catalyst precursor thus obtained was put into a tubular heat treatment tube and subjected to a calcination treatment at 200 ° C. for 2 hours while flowing hydrogen at 100 ml / min.

  In this way, a silica-supported bismuth catalyst was obtained.

  Next, 1.90 g (10.71 mmol) of palladium chloride (manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in 43 ml of 3N hydrochloric acid, and the silica-supported bismuth catalyst prepared earlier was added thereto, and the liquid was added to silica. Impregnation while stirring until completely absorbed.

  After the impregnation, the water was again removed under reduced pressure by a rotary evaporator.

  The catalyst precursor thus obtained was placed in a tubular heat treatment tube, and dried at 150 ° C. for 2 hours while flowing nitrogen at 100 ml / min. When the temperature of the catalyst layer dropped to room temperature, reduction treatment was performed at 200 ° C. for 2 hours and at 400 ° C. for 4 hours while switching nitrogen to hydrogen and flowing at 50 ml / min.

  The catalyst after the reduction treatment was repeatedly washed with ion-exchanged water until no chlorine ions were detected in the washing water by the mercuric thiocyanate method.

  After washing, the catalyst was obtained by drying at 110 ° C. for 3 hours in a dryer.

  When the thus obtained catalyst was analyzed with an X-ray diffractometer, it was found that the catalyst was different from the catalyst of the present invention as shown in FIG.

  The reaction and analysis were performed in the same manner as in Example 1 except that this catalyst was used. The results are also shown in Table 2.

Comparative Example 3
43 ml of a 7% nitric acid aqueous solution was added to 2.74 g (5.65 mmol) of bismuth nitrate pentahydrate (manufactured by Wako Pure Chemical Industries, Ltd.) to completely dissolve bismuth nitrate pentahydrate.

Next, 40 g of silica dried at 180 ° C. for 2 hours in a dryer (manufactured by Fuji Silysia Co., CARIACT-Q30, BET specific surface area: 100 m ² / g, pore volume: 1.05 cc / g, spherical diameter of 3 mm) In addition, it was impregnated with stirring until the liquid was completely absorbed by the silica.

  After the impregnation, water was removed under reduced pressure with a rotary evaporator and dried in a drier at 110 ° C. for 3 hours to obtain bismuth nitrate-supported silica.

  Next, 2.53 g (11.29 mmol) of palladium acetate (manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in 43 ml of 3.5% ammonia water, and the silica prepared on bismuth nitrate was added to the solution. The solution was impregnated with stirring until completely absorbed.

  After the impregnation, the water was again removed under reduced pressure by a rotary evaporator.

  The catalyst precursor thus obtained was put into a tubular heat treatment tube and subjected to reduction treatment at 400 ° C. for 5 hours while flowing hydrogen at 50 ml / min.

  When the thus obtained catalyst was analyzed by an X-ray diffractometer, it was found that the catalyst was different from the catalyst of the present invention as shown in FIG.

  The reaction and analysis were performed in the same manner as in Example 1 except that this catalyst was used. The results are shown in Table 2.

Comparative Example 4
2.00 g (11.28 mmol) of palladium chloride (manufactured by Wako Pure Chemical Industries, Ltd.) and 0.36 g (1.14 mmol) of bismuth chloride (manufactured by Wako Pure Chemical Industries, Ltd.) were weighed in a 200 ml round bottom flask, 43 ml of hydrochloric acid was added and stirred at room temperature until the palladium chloride and bismuth chloride were completely dissolved.

Next, 40 g of silica dried at 180 ° C. for 2 hours in a dryer (manufactured by Fuji Silysia Co., CARIACT-Q30, BET specific surface area: 100 m ² / g, pore volume: 1.05 cc / g, spherical diameter of 3 mm) In addition, it was impregnated with stirring until the liquid was completely absorbed by the silica.

  After the impregnation, water was removed under reduced pressure using a rotary evaporator.

  The catalyst precursor thus obtained was put into a tubular heat treatment tube and subjected to reduction treatment at 400 ° C. for 5 hours while flowing hydrogen at 50 ml / min.

  The catalyst after the reduction treatment was repeatedly washed with ion-exchanged water until no chlorine ions were detected in the washing water by the mercuric thiocyanate method.

  After washing, the catalyst was obtained by drying at 110 ° C. for 3 hours in a dryer.

  The catalyst thus obtained was analyzed by an X-ray diffractometer. As shown in FIG. 5, in addition to the alloy having an atomic ratio of palladium to bismuth (Pd / Bi) of 3, a peak derived from Pd metal was found. Recognized and different from the catalyst of the present invention.

  The reaction and analysis were performed in the same manner as in Example 1 except that this catalyst was used. The results are also shown in Table 2.

Comparative Example 5
2.00 g (11.28 mmol) of palladium chloride (manufactured by Wako Pure Chemical Industries, Ltd.) was weighed into a 200 ml round bottom flask, 43 ml of 6N hydrochloric acid was added, and the mixture was stirred at room temperature until the palladium chloride was completely dissolved.

Next, 40 g of silica dried at 180 ° C. for 2 hours in a dryer (manufactured by Fuji Silysia Co., CARIACT-Q30, BET specific surface area: 100 m ² / g, pore volume: 1.05 cc / g, spherical diameter of 3 mm) In addition, it was impregnated with stirring until the liquid was completely absorbed by the silica. Subsequent operations were carried out in the same manner as in Example 1 to prepare a catalyst.

  The reaction and analysis were performed in the same manner as in Example 1 except that this catalyst was used. The results are also shown in Table 2.

Comparative Example 6
1.18 g (3.74 mmol) of bismuth chloride (manufactured by Wako Pure Chemical Industries, Ltd.) was weighed into a 200 ml round bottom flask, 43 ml of 6N hydrochloric acid was added, and the mixture was stirred at room temperature until bismuth chloride was completely dissolved. Subsequent operations were carried out in the same manner as in Example 1 to prepare a catalyst.

  The reaction and analysis were performed in the same manner as in Example 1 except that this catalyst was used. As a result, no benzyl acetate was produced.

Example 2
10 cc of the catalyst prepared in Example 1 was packed in a reaction tube made of SUS316 having an inner diameter of 13 mm, reaction temperature was 170 ° C., reaction pressure was 14 kg / cm ² G, toluene was 2.2 g / min, and acetic acid was 1.4 g / min. The reaction was performed by continuously supplying 23.3 Nml / min of oxygen and 396 Nml / min of nitrogen. At this time, the partial pressure of oxygen in the gas phase in the reactor was 0.6 kg / cm ² .

  After separating the reaction product into a liquid and a gas, the liquid component and the gas component were each analyzed by gas chromatography.

  The space-time yield STY of benzyl acetate at this time was 313 g / h / L at the third hour after the start of the reaction, and the selectivity was 98% based on acetic acid.

  Further, when the elution amount of Pd in the reaction solution at this time was measured by a flameless atomic absorption method, Pd was not detected.

Comparative Example 7
The reaction was conducted under the same conditions as in Example 2 except that the same lot of catalyst as used in Comparative Example 5 was used, and the product was analyzed in the same manner. The results are shown in Table 3.

実施例３
実施例１で使用したものと同じロットの触媒を用い、トルエンを２．２ｇ／ｍｉｎ、酢酸を１．４ｇ／ｍｉｎ、酸素を３８．５Ｎｍｌ／ｍｉｎ、窒素を３８１Ｎｍｌ／ｍｉｎ（このときの反応系内における気相部分の酸素分圧は１．０ｋｇ／ｃｍ^２であった）を連続的に供給した以外は、実施例２と同じ条件で反応を行ない、生成物の分析を行った。結果を表３にあわせて示す。

Example 3
Using the same lot of catalyst as used in Example 1, 2.2 g / min of toluene, 1.4 g / min of acetic acid, 38.5 Nml / min of oxygen, and 381 Nml / min of nitrogen (reaction system at this time) The reaction was carried out under the same conditions as in Example 2 except that the oxygen partial pressure in the gas phase portion was 1.0 kg / cm ² continuously, and the product was analyzed. The results are shown in Table 3.

Example 4
Using the same lot of catalyst as used in Example 1, 2.2 g / min of toluene, 1.4 g / min of acetic acid, 58.3 Nml / min of oxygen, and 361 Nml / min of nitrogen (reaction system at this time) The reaction was performed under the same conditions as in Example 2 except that the oxygen partial pressure in the gas phase portion was 1.5 kg / cm ² continuously, and the product was analyzed. The results are shown in Table 3.

Example 5
Using the same lot of catalyst as used in Example 1, 2.8 g / min of toluene, 1.8 g / min of acetic acid, 58.3 Nml / min of oxygen, and 990 Nml / min of nitrogen (reaction system at this time) The reaction was performed under the same conditions as in Example 2 except that the oxygen partial pressure in the gas phase portion was 0.6 kg / cm ² continuously, and the product was analyzed. The results are shown in Table 3.

Example 6
Using the same lot of catalyst as used in Example 1, 2.2 g / min of toluene, 1.4 g / min of acetic acid, 87.5 Nml / min of oxygen, and 332 Nml / min of nitrogen (reaction system at this time) The product was analyzed under the same conditions as in Example 2 except that the oxygen partial pressure in the gas phase portion was 2.25 kg / cm ² continuously. The results are shown in Table 3.

Example 7
Using the same lot of catalyst as used in Example 1, toluene was 2.2 g / min, acetic acid was 1.4 g / min, oxygen was 117 Nml / min, and nitrogen was 303 Nml / min (in this reaction system, The reaction was conducted under the same conditions as in Example 2 except that the oxygen partial pressure in the gas phase portion was 3.0 kg / cm ² continuously, and the product was analyzed. The results are shown in Table 3.

Example 8
10 cc of the catalyst prepared in Example 1 and 10 cc of glass beads having a diameter of 1 mm were mixed and packed in a reaction tube made of SUS316 having an inner diameter of 13 mm. The reaction temperature was 170 ° C., the reaction pressure was 44 kg / cm ² G, and toluene was 0.14 g / The reaction was performed by continuously supplying min, 0.1 g / min of acetic acid, 2.7 Nml / h of oxygen (0.7 mol / h with respect to 1 liter of catalyst), and 209 Nml / h of nitrogen.

  After separating the reaction product into a liquid and a gas, the liquid component and the gas component were each analyzed by gas chromatography.

  The space-time yield STY of benzyl acetate at this time was 83 g / h / L at 20 hours after the start of the reaction, and the selectivity was 95% based on acetic acid.

  In addition, the time until the benzyl acetate STY was halved from the general formula for catalyst deterioration represented by the above formula (2) exceeded 10,000 hours.

Example 9
Using the same lot of catalyst as used in Example 1, 0.14 g / min of toluene, 0.1 g / min of acetic acid, 7.8 Nml / min of oxygen (2.1 mol / h with respect to 1 liter of catalyst) ), Except that nitrogen was continuously supplied at 204 Nml / min, under the same conditions as in Example 8, and the product was analyzed. The results are shown in Table 4.

実施例１０
実施例１で使用したのと同じロットの触媒を用い、トルエンを０．１４ｇ／ｍｉｎ、酢酸を０．１ｇ／ｍｉｎ、酸素を１５．６Ｎｍｌ／ｍｉｎ（触媒１リットルに対して４．２ｍｏｌ／ｈ）、窒素を１９６Ｎｍｌ／ｍｉｎ連続的に供給した以外は、実施例８と同じ条件で行い、生成物の分析を行った。結果を表４にあわせて示す。

Example 10
Using the same lot of catalyst as used in Example 1, 0.14 g / min of toluene, 0.1 g / min of acetic acid, 15.6 Nml / min of oxygen (4.2 mol / h with respect to 1 liter of catalyst) ), Except that nitrogen was continuously supplied at 196 Nml / min, and the product was analyzed under the same conditions as in Example 8. The results are shown in Table 4.

Example 11
The same lot of catalyst as used in Example 1 was used, the reaction pressure was 14 kg / cm ² G, toluene was 0.3 g / min, acetic acid was 0.2 g / min, and oxygen was 5.8 Nml / min (catalyst 1 The product was analyzed under the same conditions as in Example 8 except that nitrogen was continuously supplied at 51 Nml / min and 1.6 mol / h per liter. The results are shown in Table 4.

Example 12
Using the same lot of catalyst as used in Example 1, 0.14 g / min of toluene, 0.1 g / min of acetic acid, 20.7 Nml / min of oxygen (5.5 mol / h with respect to 1 liter of catalyst) ), Except that nitrogen was continuously supplied at 191 Nml / min, and the product was analyzed under the same conditions as in Example 8. The results are shown in Table 4.

Example 13
Using the same lot of catalyst as used in Example 1, 0.14 g / min of toluene, 0.1 g / min of acetic acid, 1.5 Nml / h of oxygen (0.4 mol / h with respect to 1 liter of catalyst) The product was analyzed under the same conditions as in Example 8 except that nitrogen was continuously supplied at 210 Nml / min. The results are shown in Table 4.

Example 14
Example 2 except that the supply amounts of toluene and acetic acid were 3.1 g / min of toluene and 0.4 g / min of acetic acid [At this time, acetic acid / toluene = 0.25 (molar ratio)]. Reaction and analysis were performed. The results are shown in Table 5.

実施例１５
トルエン及び酢酸の供給量を、トルエン１．０ｇ／ｍｉｎ、酢酸２．７ｇ／ｍｉｎ［このとき、酢酸／トルエン＝４（モル比）である］とした以外は、実施例２と同様に反応及び分析を行った。結果を表５にあわせて示す。

Example 15
The reaction and the reaction were carried out in the same manner as in Example 2 except that the supply amounts of toluene and acetic acid were 1.0 g / min of toluene and 2.7 g / min of acetic acid [at this time, acetic acid / toluene = 4 (molar ratio)]. Analysis was carried out. The results are shown in Table 5.

Example 16
The same as Example 2 except that the supply amounts of toluene and acetic acid were 3.4 g / min of toluene and 0.2 g / min of acetic acid [At this time, acetic acid / toluene = 0.11 (molar ratio)]. Reaction and analysis were performed. The results are shown in Table 5.

Example 17
The reaction and the reaction were carried out in the same manner as in Example 2 except that the supply amounts of toluene and acetic acid were 0.1 g / min of toluene and 3.6 g / min of acetic acid [At this time, acetic acid / toluene = 49 (molar ratio)]. Analysis was carried out. The results are shown in Table 5.

Example 18
10 cc of the catalyst prepared by the same method as in Example 1 was packed in a reaction tube made of SUS316 having an inner diameter of 13 mm.

0.01 g of bismuth oxide as a bismuth soluble compound was dissolved in 19 kg of an equimolar mixture of toluene and acetic acid [At this time, the amount of bismuth in terms of metal in the mixture was 5 × 10 ⁻⁷ (weight ratio). ].

Under a reaction temperature of 170 ° C. and a reaction pressure of 14 kg / cm ² G, in a reaction tube packed with a catalyst, a mixed solution of toluene and acetic acid in which bismuth oxide was dissolved was 3.65 g / min, and oxygen was 23.3 Nml / min. Nitrogen was supplied at 396 Nml / min for reaction.

  At this time, the space time yield (STY) of benzyl acetate was 286 g / h / L at the third hour of the reaction, and no decrease in STY was observed for 300 hours. During this time, Pd was not detected in the reaction solution. The results are shown in Table 6.

実施例１９
酸化ビスマスを０．００１ｇ用いた［このとき、混合液中の金属換算のビスマス量は５×１０^−８（重量比）であった］以外は、実施例１８と同様に反応及び分析を行った。結果を表６にあわせて示す。

Example 19
The reaction and analysis were performed in the same manner as in Example 18 except that 0.001 g of bismuth oxide was used [the amount of bismuth in terms of metal in the mixed solution was 5 × 10 ⁻⁸ (weight ratio)]. . The results are shown in Table 6.

Example 20
Except that 0.02 g of bismuth nitrate pentahydrate was used as a soluble compound of bismuth, except that the amount of bismuth in terms of metal in the mixed solution was 5 × 10 ⁻⁷ (weight ratio). Reaction and analysis were carried out in the same manner as in No.18. The results are shown in Table 6.

Example 21
10 cc of the catalyst prepared by the same method as in Example 1 was packed in a reaction tube made of SUS316 having an inner diameter of 28 mm.

0.13 g of bismuth oxyacetate as a soluble compound of bismuth was dissolved in 19 kg of an equimolar mixture of toluene and acetic acid [At this time, the amount of bismuth in terms of metal in the mixed solution was 5 × 10 ⁻⁶ (weight ratio). ]

Under a reaction temperature of 170 ° C. and a reaction pressure of 14 kg / cm ² G, in a reaction tube packed with a catalyst, a mixed solution of toluene and acetic acid in which bismuth oxide was dissolved was 3.65 g / min, oxygen was 47 Nml / min, nitrogen 372 Nml / min was supplied for reaction.

  After separating the reaction product into a liquid and a gas, the liquid component and the gas component were analyzed by gas chromatography. The results are shown in Table 6.

2 is an XRD chart of the catalyst obtained in Example 1. 3 is an XRD chart of a catalyst obtained in Comparative Example 1. 3 is an XRD chart of a catalyst obtained in Comparative Example 2. 6 is an XRD chart of the catalyst obtained in Comparative Example 3. 6 is an XRD chart of a catalyst obtained in Comparative Example 4.

Claims (8)

In the method for producing benzyl acetate by reacting toluene, acetic acid and oxygen in the liquid phase, potassium acetate is not used in the reaction, and it is composed of palladium and bismuth, and palladium / bismuth = 2.5-3 (atomic ratio). A catalyst in which an alloy is supported on silica is used, and palladium supported on silica is substantially an alloy composed of palladium and bismuth, and the alloy composed of palladium and bismuth contains carbon monoxide. A method for producing benzyl acetate, which does not adsorb and further exhibits the following X-ray diffraction pattern.

The production method according to claim 1, wherein the catalyst is prepared by simultaneously supporting raw material salts of palladium and bismuth on silica. 3. The production according to claim 1, wherein the catalyst is prepared by supporting a raw material salt of palladium and bismuth with palladium / bismuth = 2.5 to 3 (atomic ratio). Method. 4. The production method according to claim 1, wherein the partial pressure of oxygen in the gas phase portion in the reactor is in the range of 0.1 to ² kg / cm < ² >. The production method according to any one of claims 1 to 4, wherein an oxygen supply amount is in a range of 0.5 to 4.5 mol / h with respect to 1 liter of catalyst volume. The production method according to any one of claims 1 to 3 , wherein the reaction is performed within a mixing ratio of toluene and acetic acid within a range of 0.2 to 40 (molar ratio) of acetic acid based on toluene. The production method according to claim 1, wherein the reaction is carried out by dissolving a soluble compound of bismuth in toluene and / or acetic acid. The production method according to claim 7, wherein the amount of the bismuth soluble compound is within the range of the following formula (1).

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