JP3103500B2 - Method for producing carboxylic acid ester - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a carboxylic acid ester from an aldehyde and an alcohol in a single step,
In particular, the present invention relates to a method for advantageously producing a methacrylate or acrylate having high industrial value from methacrolein or acrolein.

[0002]

2. Description of the Related Art At present, in the production of methacrylic acid esters and acrylic acid esters, a carboxylic acid is produced by gas phase catalytic oxidation of methacrolein or acrolein using a catalyst, and then reacted with an alcohol to esterify the carboxylic acid ester. Manufacturing methods have been industrialized. In particular, phosphorus used for the oxidation of methacrolein,
Molybdenum-based heteropolyacid catalysts include:
At present, improvement studies are being continued due to shortcomings in terms of catalyst life and yield. In addition, this production method has a drawback that it requires a large amount of equipment because it involves two steps, an oxidation step and an esterification step.

[0003] In view of the above, several attempts have been made to produce a carboxylic acid ester from an aldehyde and an alcohol in one step with a high yield. In the gas phase method, Japanese Patent Publication No. 53-1549
No. 2 proposes a single-stage production method using Pd, P, and Sb-based catalysts. On the other hand, in the liquid phase method,
7-35856, JP-B-4-72578, JP-A-5
JP-A-7-50545 discloses a Pd and Pb-based catalyst, JP-A-61-243044 discloses a Pd and Te-based catalyst, and JP-B-57-35860 discloses a Pd, Tl, and Hg-based catalyst. No. 190090 discloses Pd, alkaline earth metal, Zn and Cd-based catalysts.
No., JP-B-62-7902, JP-A-5-148184
Publications propose Pd and Bi-based catalysts.

[0004] On the other hand, the performance of the catalyst carrier has been improved.
Improvement research is being conducted to make this possible. Tokiko 57-3
No. 5856 and JP-B-57-35860 describe catalysts.
An example using calcium carbonate as a carrier is disclosed in
No. 46618 discloses zinc oxide-alumina, titania
-Lanthanum oxide, zinc oxide-using titania as catalyst carrier
For example, Japanese Patent Publication No. 4-72578 discloses zinc oxide.
An example for use as a catalyst carrier has been proposed. In addition, Japanese Unexamined Patent Publication No.
No. 7-50942 discloses that the specific surface area is 70 m. ^Two / G or less
Lower catalyst support (silica, alumina, titania, zirconi
A, diatomaceous earth, silicon carbide, silica aluminum
Japanese Patent Application Laid-Open No. 148184/1993
Means that Teflon, fluorinated graphite,
An example using isola zeolite or the like has been proposed.

[0005]

However, in these single-step methods for producing carboxylic acid esters, the reaction rate is low, the reaction product is obtained as an alcohol solution of the carboxylic acid ester having a low concentration, and by-products such as methyl formate are produced. Further improvements are desired in that many products are produced, the life of the catalyst is short, and the yield is not yet sufficient.

An object of the present invention is to provide a novel catalyst having an excellent activity and selectivity for a desired product for advantageously producing a carboxylic acid ester in one step from an aldehyde and an alcohol.

[0007]

That is, the present invention provides a method for producing a carboxylic acid ester by reacting an aldehyde and an alcohol in a liquid phase in the presence of molecular oxygen.
A catalyst is used in which palladium, bismuth, and at least one element selected from the group consisting of lead, iron, manganese, cobalt, nickel, copper, zinc, germanium, barium, and tellurium are supported on zinc oxide. A method for producing a carboxylic acid ester, characterized in that:

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The aldehyde used as a raw material in the production method of the present invention includes acetaldehyde,
Examples include saturated aldehydes such as propionaldehyde and isobutyraldehyde, and unsaturated aldehydes such as acrolein, methacrolein, and crotonaldehyde. Above all, methacrolein, acrolein and mixtures thereof are important as starting materials for producing methacrylic esters and acrylic esters having high industrial value. Examples of the alcohol include methanol, ethanol, isopropanol, allyl alcohol, and methallyl alcohol.

In the catalyst used in the present invention, it is essential that palladium and bismuth are supported on a support made of zinc oxide. In addition to these, lead, iron, manganese, cobalt, nickel, copper At least one selected from the group consisting of zinc, germanium, barium and tellurium
It is a catalyst in which a certain element is supported. As the raw material compound of the catalyst component, palladium raw material, palladium acetate, palladium chloride, palladium nitrate, palladium sulfate, palladium ammonium chloride, palladium ammine complex salt, etc., as the bismuth raw material, bismuth acetate, bismuth carbonate, bismuth chloride, Bismuth nitrate, bismuth sulfate and the like can be used. As other metal raw materials, general metal compounds of acetate, carbonate, nitrate, sulfate, oxalate or chloride thereof can be used.

The amount of the catalyst component supported on zinc oxide is 1 to 15% by weight, preferably 3 to 13% by weight, based on zinc oxide, in the form of reduced metal for palladium. For bismuth, it is 0.1 to 15% by weight, preferably 0.5 to 12% by weight, calculated as metal, in the form of a metal or a bismuth compound. Further, at least one element selected from the group consisting of lead, iron, manganese, cobalt, nickel, copper, zinc, germanium, barium and tellurium, in the form of these metals or in the form of these metal compounds, 0.1 ~
It is 15% by weight, preferably 0.5 to 12% by weight.

This catalyst can be produced according to a conventional method. As an example, a method for preparing a catalyst in which palladium, bismuth and lead are supported on a zinc oxide carrier will be described. Zinc oxide powder is put in water, a predetermined amount of a palladium chloride solution is added thereto, and the mixture is stirred. Next, the resulting suspension is reduced with a reducing agent such as formalin to precipitate metallic palladium, filtered, immersed in an aqueous solution of bismuth nitrate and lead nitrate, and reduced again with a reducing agent to precipitate the metal, if desired. After filtration, it can be prepared by drying under reduced pressure. The catalyst thus prepared can be activated according to a conventional method.

In the production method of the present invention, the supply ratio of the aldehyde and the alcohol as the raw material compounds is 1:10 in molar ratio.
0 to 1: 1 is appropriate, and particularly preferably 1:80 to 1: 3.

The reaction is usually carried out in a liquid phase comprising a mixture of the starting compounds, but an inert solvent such as hexane, benzene, dioxane or the like may be used for the reaction components. The catalyst is preferably used in a suspended state. The reaction system may be any of a batch system, a semi-batch system, and a continuous system.

As the molecular oxygen as the oxidizing agent used in the present invention, air, oxygen-enriched air, oxygen, hydrogen peroxide or the like can be used, and is usually supplied by blowing gas such as air into the reaction system. Is done.

In the method of the present invention, the reaction temperature is from 0 to 100 ° C.
It is suitably carried out at 30 to 80 ° C.
The reaction can be performed under normal pressure, but may be performed under pressure. Also,
If necessary, a polymerization inhibitor such as hydroquinone or p-methoxyphenol may be added to the reaction solution.

[0016]

EXAMPLES Hereinafter, the method of the present invention will be described in more detail with reference to Examples and Comparative Examples. The supported amount of the metal compound with respect to zinc oxide means weight% calculated as metal based on zinc oxide. The analysis of the reaction product was performed by gas chromatography. The conversion (%) and selectivity (%) in Table 1 mean the conversion (%) of methacrolein and the selectivity (%) of methyl methacrylate unless otherwise specified.

Example 1 1.40 g of tetraamminepalladium nitrate was dissolved in 20 ml of pure water, 10 g of zinc oxide was added thereto, and the mixture was refluxed for 1 hour with stirring. Next, after removing water, 20 ml of an aqueous formalin solution was added, followed by filtration and washing with water to obtain a solid. Next, bismuth nitrate 0.4
The solid was added to a solution of 6 g of lead acetate and 0.18 g of lead acetate in 40 ml of 1% diluted nitric acid, and mixed at 60 ° C. for 1 hour. After mixing, 15 ml of formalin aqueous solution was added, followed by filtration,
After washing with water and drying, a zinc oxide catalyst supporting 5% by weight of palladium, 2% by weight of bismuth and 1% by weight of lead was obtained.

Into a 200 ml flask equipped with a reflux condenser were charged 2.0 g of the catalyst prepared above, 3.5 g of methacrolein and 80 g of methanol. Further, when the pH of the reaction solution is 1
A methanol solution of 0.03 N NaOH was added so that the solution became 0.5, and the reaction was carried out at a bath temperature of 70 ° C. for 4 hours while blowing air at a rate of 100 ml per minute to synthesize methyl methacrylate. As a result of collecting and analyzing the reaction product, the conversion of methacrolein was 76.9% and the selectivity of methyl methacrylate was 96.8%.

[Example 2] Instead of lead acetate, lead nitrate was added to 0.1%.
A catalyst was prepared in the same manner as in Example 1 except that 32 g was used, and a 5% by weight palladium-2% by weight bismuth-2% by weight lead-supported zinc oxide catalyst was obtained. Table 1 shows the conversion of methacrolein and the selectivity of methyl methacrylate as a result of synthesizing methyl methacrylate under the same reaction conditions as in Example 1 using this catalyst.

Example 3 A catalyst was prepared in the same manner as in Example 1 except that 0.72 g of ferric nitrate was used instead of lead acetate, and 5% by weight of palladium-2% by weight of bismuth-1% by weight of iron A supported zinc oxide catalyst was obtained. Table 1 shows the results of synthesizing methyl methacrylate using this catalyst under the same reaction conditions as in Example 1.

Example 4 A catalyst was prepared in the same manner as in Example 1 except that 0.45 g of manganese acetate was used instead of lead acetate, and 5% by weight of palladium-2% by weight of bismuth-
A 1% by weight manganese-supported zinc oxide catalyst was obtained. Table 1 shows the results of synthesizing methyl methacrylate using this catalyst under the same reaction conditions as in Example 1.

Example 5 A catalyst was prepared in the same manner as in Example 1 except that 0.42 g of cobalt acetate was used instead of lead acetate, and 5% by weight of palladium-2% by weight of bismuth-
A 1% by weight cobalt-supported zinc oxide catalyst was obtained. Table 1 shows the results of synthesizing methyl methacrylate using this catalyst under the same reaction conditions as in Example 1.

Example 6 A catalyst was prepared in the same manner as in Example 1 except that 0.50 g of nickel nitrate was used instead of lead acetate, and 5% by weight of palladium-2% by weight of bismuth-
A 1% by weight nickel-supported zinc oxide catalyst was obtained. Table 1 shows the results of synthesizing methyl methacrylate using this catalyst under the same reaction conditions as in Example 1.

Example 7 A catalyst was prepared in the same manner as in Example 1 except that 0.39 g of cuprous sulfate was used instead of lead acetate, and 5% by weight of palladium-2% by weight of bismuth-1
A weight percent copper-supported zinc oxide catalyst was obtained. Table 1 shows the results of synthesizing methyl methacrylate using this catalyst under the same reaction conditions as in Example 1.

Example 8 A catalyst was prepared in the same manner as in Example 1 except that 0.34 g of zinc acetate was used instead of lead acetate, and 5% by weight of palladium-2% by weight of bismuth-1
A weight-% zinc-supported zinc oxide catalyst was obtained. Table 1 shows the results of synthesizing methyl methacrylate using this catalyst under the same reaction conditions as in Example 1.

Example 9 A catalyst was prepared in the same manner as in Example 1 except that 0.14 g of germanium dioxide was used instead of lead acetate, and 5% by weight of palladium-2% by weight of bismuth-1% by weight of germanium was supported. A zinc oxide catalyst was obtained.
Table 1 shows the results of synthesizing methyl methacrylate using this catalyst under the same reaction conditions as in Example 1.

Example 10 A catalyst was prepared in the same manner as in Example 1 except that 0.19 g of barium acetate was used instead of lead acetate, and 5% by weight of palladium-2% by weight of bismuth-1% by weight of barium was supported. A zinc oxide catalyst was obtained. Table 1 shows the results of synthesizing methyl methacrylate using this catalyst under the same reaction conditions as in Example 1.

Example 11 A catalyst was prepared in the same manner as in Example 1 except that 0.18 g of telluric acid was used instead of lead acetate, and 5% by weight of palladium-2% by weight of bismuth-1
By weight, a zinc oxide catalyst supported on tellurium was obtained. Table 1 shows the results of synthesizing methyl methacrylate using this catalyst under the same reaction conditions as in Example 1.

Example 12 Methyl methacrylate was synthesized under the same reaction conditions as in Example 1 except that the amount of the catalyst prepared in Example 1 was increased to 4.0 g by the reaction. The results are shown in Table 1.

Example 13 A 200 ml flask equipped with a reflux condenser was charged with 4.0 g of the catalyst prepared in Example 1, 7.0 g of methacrolein and 80 g of methanol. Further, a methanol solution of 0.03 N NaOH was added so that the pH of the reaction solution became 10.5, and air was added at 200 ml / min.
The reaction was carried out at a bath temperature of 70 ° C. for 4 hours while blowing at a rate of 1 to synthesize methyl methacrylate. The results are shown in Table 1.

Example 14 Methyl methacrylate was synthesized under the same reaction conditions as in Example 1 except that the temperature of the reaction bath was set at 40 ° C. using the catalyst of Example 1. Table 1 shows the results.
It was shown to.

Example 15 Methyl methacrylate was synthesized under the same reaction conditions as in Example 1 except that the reaction bath temperature was 55 ° C. using the catalyst of Example 1. Table 1 shows the results.
It was shown to.

Example 16 The amount of bismuth nitrate was 0.7
A catalyst was prepared in the same manner as in Example 1 except that the amount was 0 g,
A 5% by weight palladium-3% by weight bismuth-1% by weight lead-supported zinc oxide catalyst was obtained. Table 1 shows the results of synthesizing methyl methacrylate using this catalyst under the same reaction conditions as in Example 1.

Example 17 1.40 g of tetraamminepalladium nitrate was dissolved in 20 ml of pure water, and 10 g of zinc oxide was added thereto, followed by refluxing for 1 hour with stirring. Next, after removing water, 20 ml of formalin aqueous solution was added,
After filtration and washing with water, a solid was obtained. Next, bismuth nitrate 0.
The above solid matter was added to a solution of 46 g, 0.18 g of lead acetate and 0.72 g of ferric nitrate in 60 ml of 1% diluted nitric acid, and mixed at 60 ° C. for 1 hour. After mixing, 15 ml of a formalin aqueous solution was added, and the mixture was filtered, washed with water, and dried to obtain a zinc oxide catalyst supporting 5% by weight of palladium, 2% by weight of bismuth, 1% by weight of lead, and 1% by weight of iron. Table 1 shows the results of synthesizing methyl methacrylate using this catalyst under the same reaction conditions as in Example 1.

Example 18 Methyl acrylate was synthesized under the same reaction conditions as in Example 1 except that 2.80 g of acrolein was used instead of methacrolein using the catalyst of Example 1. The results are shown in Table 1. In the table, the conversion indicates the conversion of acrolein, and the selectivity indicates the selectivity of methyl acrylate.

Comparative Example 1 1.40 g of tetraamminepalladium nitrate was dissolved in 20 ml of pure water, and 10 g of zinc oxide was added thereto, followed by refluxing for 1 hour with stirring. Next, after removing water, 20 ml of an aqueous formalin solution was added, followed by filtration and washing with water to obtain a solid. Next, bismuth nitrate 0.4
The solid was added to a solution of 6 g in 40 ml of 1% diluted nitric acid, and mixed at 60 ° C. for 1 hour. After mixing, 15 ml of a formalin aqueous solution was added, and the mixture was filtered, washed with water, dried, and dried.
Thus, a zinc oxide catalyst supporting 2% by weight of palladium and 2% by weight of bismuth was obtained. Table 1 shows the results of synthesizing methyl methacrylate using this catalyst under the same reaction conditions as in Example 1. The selectivity was reduced for the catalyst supporting only palladium and bismuth.

Comparative Example 2 A magnesium oxide catalyst supporting 5% by weight of palladium, 2% by weight of bismuth and 1% by weight of lead was prepared in the same manner as in Example 1, and methacrylic acid was prepared under the same conditions as in Example 1. The synthesis of methyl was performed. The results are shown in Table 1. When magnesium oxide was used as a carrier, the selectivity was significantly reduced.

Comparative Example 3 A zirconium oxide catalyst supporting 5% by weight of palladium-2% by weight of bismuth-1% by weight of lead was prepared in the same manner as in Example 1, and methacrylic acid was prepared under the same conditions as in Example 1. The synthesis of methyl was performed. The results are shown in Table 1. When zirconium oxide was used as the carrier, the selectivity was significantly reduced.

Comparative Example 4 A titanium dioxide catalyst supporting 5% by weight of palladium-2% by weight of bismuth-1% by weight of lead was prepared in the same manner as in Example 1, and methacrylic acid was prepared under the same conditions as in Example 1. The synthesis of methyl was performed. The results are shown in Table 1. When titanium dioxide was used as the carrier, the selectivity was significantly reduced.

Comparative Example 5 A magnesium carbonate catalyst supporting 5% by weight of palladium, 2% by weight of bismuth and 1% by weight of lead was prepared in the same manner as in Example 1, and methacrylic acid was prepared under the same conditions as in Example 1. The synthesis of methyl was performed. The results are shown in Table 1. When magnesium carbonate was used as a carrier, the conversion and selectivity were significantly reduced.

[0041]

[Table 1]

[0042]

As is clear from the above examples, according to the production method of the present invention, a carboxylic acid ester is produced from an aldehyde and an alcohol in one step with high catalytic activity and good selectivity of a target product. It is possible to

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-6-80611 (JP, A) JP-A-5-148184 (JP, A) JP-A-59-162947 (JP, A) JP-A-58-1983 198442 (JP, A) JP-A-58-166936 (JP, A) JP-A-55-153741 (JP, A) JP-A-55-151533 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C07C 69/54 C07C 67/39 C07B 61/00 300

Claims (1)

(57) [Claims] 1. A method for producing a carboxylic acid ester by reacting an aldehyde and an alcohol in a liquid phase in the presence of molecular oxygen, wherein palladium, bismuth, lead, iron,
Manufacture of a carboxylic acid ester characterized by using a catalyst comprising zinc oxide and at least one element selected from the group consisting of manganese, cobalt, nickel, copper, zinc, germanium, barium and tellurium. Method.