JPH07258163A - Production of glyoxylic acid ester - Google Patents

Abstract

PURPOSE:To obtain the compound useful as an intermediate, etc., for medicines and agrochemicals at a high production rate by catalytically reacting a glycolic acid ester with molecular oxygen in the vapor phase using a novel catalyst. CONSTITUTION:This method for producing a glyoxylic acid ester is to react a glycolic acid ester (preferably methyl glycolate or ethyl glycolate) with molecular oxygen (usually air) in the vapor phase in the presence of an unsupported phosphoric acid catalyst (preferably powder having 20-100mum grain diameter or a molding having a particle size of 4-200 mesh. The catalyst is obtained by adding, e.g. water to copper phosphate and drying the resultant slurry at 110 deg.C. Furthermore, the reaction is preferably carried out by feeding the glycolic acid ester at a flow rate of 0.2-3g/hr based on 1g catalyst and the molecular oxygen at 0.5-3molar ratio to the glycolic acid ester at a flow rate of 1-15ml/min based on 1g catalyst to a reactor filled with the catalyst under conditions of 200-350 deg.C and normal pressure to 5kg/cm<2>.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention uses a novel catalyst to
The present invention relates to a method for producing a glyoxylic acid ester by subjecting a glycolic acid ester and molecular oxygen to a gas phase catalytic reaction. Glyoxylic acid ester is a very useful compound as a builder for detergents, a raw material for vanillin, and an intermediate for medicines and agricultural chemicals and polymers.

[0002]

2. Description of the Related Art Conventionally, as a method for producing a glyoxylic acid ester, there has been known a method in which a glycolic acid ester and a molecular oxygen are subjected to a gas phase catalytic reaction in the presence of various catalysts. For example, in U.S. Pat. No. 4,340,748, at least one element selected from vanadium, molybdenum, silver, and copper, tin, antimony, bismuth, and periodic table 1
A method of using a catalyst containing at least one element of the main group element and the second main group element is disclosed, but the production rate (space-time yield) is low, and the amount of fed gas is very large. Therefore, there is a problem that productivity is not high. Further, this patent also describes that the main group elements of Groups 3 to 5 of the Periodic Table are effective, but it is not specifically exemplified.

Japanese Unexamined Patent Publication No. 60-152442 discloses a method of using unsupported metallic silver as a catalyst.
In this method, it is necessary to suppress the conversion rate of the glycolic acid ester in order to increase the selectivity of the glyoxylic acid ester, and the yield of the glyoxylic acid ester is about 69% at the maximum, and the glyoxylic acid ester selectivity is about 69%. It was about 62%, which was calculated from 89%, which was low. Japanese Patent Application Laid-Open No. 61-97247 discloses a method of using a catalyst containing a silver compound and a phosphorus compound as a method for producing an α-ketone acid ester. In this method as well, the glycolic acid ester conversion rate is 95%. Although it is high, the selectivity of glyoxylic acid ester is low at about 8%,
Similarly, there is a problem that the yield of glyoxylic acid ester is low. Thus, in the production of glyoxylic acid ester, the effect of adding phosphorus to the element effective as a catalyst has not been recognized at all.

On the other hand, in Japanese Patent Laid-Open No. 2-91046, α
-A method of using a catalyst in which ferric phosphate is supported on an alumina carrier is disclosed, but in this method, the yield of glyoxylic acid ester obtained from the conversion rate of glycolic acid ester and the selectivity of glyoxylic acid ester is not sufficient. In addition to being not high, the gas flow rate is large, and further, there is a problem that a complicated pretreatment is required for catalyst preparation, and that the reactor requires a preheating device before the reactor.

[0005]

DISCLOSURE OF THE INVENTION According to the present invention, a glycolic acid ester and a molecular oxygen are subjected to a gas phase catalytic reaction to give a glyoxylic acid ester at a high selectivity (ie, a high selectivity) by increasing the conversion rate of the glycolic acid ester. It is an object of the present invention to provide a method which can be produced with a high yield (space-time yield).

[0006]

The object of the present invention is to provide a method for producing a glyoxylic acid ester, which comprises reacting a glycolic acid ester with molecular oxygen in a gas phase in the presence of an unsupported copper phosphate catalyst. To be achieved.

The present invention will be described in detail below. Examples of the glycolic acid ester used in the present invention include esters of glycolic acid and an aliphatic lower alcohol having 1 to 6 carbon atoms. Specific examples thereof include methyl glycolate, ethyl glycolate, n-propyl glycolate, i-propyl glycolate, n-butyl glycolate, n-pentyl glycolate and n-hexyl glycolate. Of these, methyl glycolate and ethyl glycolate are preferable.

Air is generally used as the molecular oxygen used in the present invention, but air or oxygen gas diluted with an inert gas such as nitrogen or argon may be used. At this time, the air or oxygen gas is diluted so that the molar ratio of the inert gas to oxygen is usually 2 to 50, preferably 4 to 30.

The unsupported copper phosphate catalyst used in the present invention is a powder or a molded body of copper phosphate (cupric phosphate). The particle size is not particularly limited, but powders having a particle size of 20 to 100 μm and molded articles having a particle size of 4 to 200 mesh are preferably used.

Further, the catalyst may contain a metal other than copper in the form of a phosphate, an oxide or a metal. Examples of other metals include alkali metals such as lithium and potassium, alkaline earth metals such as magnesium and calcium, lanthanide metals such as lanthanum and cerium, and molybdenum, tin, manganese, bismuth, cobalt, silver, lead and antimony. , Iron, but it is preferable that each of these metals is contained in the catalyst in an atomic ratio to copper (other metals / copper) of usually 2 or less, particularly 1.5 or less. .

The method for preparing the above-mentioned catalyst is not particularly limited as long as the catalyst contains copper phosphate.
A method of preparing a slurry by adding water to a phosphate, an oxide, or a mixture with a metal of another metal, if necessary, copper phosphate and a method other than phosphate. Stoichiometric amount of phosphoric acid is added to an aqueous solution of copper and other metal salts, or a mixture of copper salts other than phosphate and oxides or metals of other metals to which water is added to form a slurry. A known method such as a method of preparing by adding and then drying at around 110 ° C. can be mentioned. In these methods,
After the catalyst is dried, it is once pulverized into a powder and molded as it is or into pellets, and then calcined in air at 300 to 900 ° C. The obtained powder or pellet is used in the reaction by adjusting the size.

The salts of copper and other metals other than the phosphate used in the catalyst preparation include cupric nitrate, copper sulfate,
Copper nitrate such as cupric chloride, sulfate or chloride, nitrate of alkali metal such as lithium and potassium, sulfate or chloride, nitrate of alkaline earth metal such as magnesium and calcium, sulfate or chloride, Examples include nitrates, sulfates or chlorides of lanthanide metals such as lanthanum and cerium, molybdenum, tin, manganese, bismuth, cobalt, silver, lead, antimony, iron nitrates, sulfates or chlorides.

In the present invention, a glyoxylic acid ester can be produced by subjecting the glycolic acid ester and the molecular oxygen to a gas phase catalytic reaction in the presence of the catalyst under the following reaction conditions. That is, this gas phase catalytic reaction is usually
Reaction temperature is 150 to 400 ° C., preferably 200 to 35
At 0 ° C., under a reaction pressure of from normal pressure to 5 kg / cm ³ , a reactor filled with a catalyst is charged with a glycolic acid ester in an amount of 0.2 to 6 g / hr, preferably 0.
3 to 3 g / hr, and 0.5 to 30 ml / min of molecular oxygen per 1 g of catalyst, preferably 1 to 15 ml / min
It is performed by feeding at a flow rate of min. At this time, the molar ratio of oxygen to glycolic acid ester (oxygen / glycolic acid ester) is usually 0.3 to 5, preferably 0.5.
~ 3. The reactor is not particularly limited as long as it can carry out a gas phase flow type reaction, and the existing form of the catalyst may be any known fixed bed, fluidized bed, boiling bed, etc.
Usually a fixed bed is preferred.

In the present invention, the glycolic acid ester is alcohol, water, acetonitrile, toluene,
It is also possible to feed by diluting with a solvent inert to the reaction such as cyclohexane, and by diluting with these solvents, the selectivity of glyoxylic acid ester can be improved. At this time, the weight ratio of the solvent to the glycolic acid ester (solvent / glycolic acid ester) is usually 0.02 to 0.8, preferably 0.04 to 0.6. As the alcohol, aliphatic lower alcohols having 1 to 6 carbon atoms such as methanol, ethanol, n-propanol, i-propanol, n-butanol, n-pentanol and n-hexanol are used, but among them, methanol , Ethanol is preferred.

As described above, as glyoxylic acid ester, methyl glyoxylate, ethyl glyoxylate, n-propyl glyoxylate, and glyoxylic acid i-
Glyoxylic acid such as propyl, n-butyl glyoxylate, n-pentyl glyoxylate, and n-hexyl glyoxylate, and glycolic acid ester in which an ester of an aliphatic lower alcohol having 1 to 6 carbon atoms is unreacted or by-product water, etc. The target glyoxylic acid ester can be separated and purified by a known method such as distillation.

[0016]

EXAMPLES Next, the present invention will be specifically described with reference to Examples and Comparative Examples. The space-time yield (g / l · hr) of glyoxylic acid ester, the conversion rate (%) of glycolic acid ester, the selectivity (%) of glyoxylic acid ester, and the yield of glyoxylic acid ester in each Example and Comparative Example. (%) Was calculated by the following formula.

[0017]

[Equation 1]

[0018]

[Equation 2]

[0019]

[Equation 3]

[0020]

[Equation 4]

Example 1 [Preparation of catalyst] Copper phosphate trihydrate [Cu
_{3 (PO 4) 2 · 3H} 2 O ] 43.5g (100mmo
The catalyst preparation solution containing 1) was kneaded and crushed for 30 minutes, and then dried in air at 110 ° C. for 12 hours. Next, this dried product is pulverized into powder and molded into pellets of 5 mmφ,
After calcining at ℃ for 5 hours, the calcined product was crushed to 1 to 2 mm to prepare a catalyst.

[Production of Methyl Glyoxylate] 8 ml of the above catalyst was charged into a glass reaction tube having an inner diameter of 9 mm, 20 ml of glass beads was further charged onto the reaction tube, and the reaction tube was installed vertically in an electric furnace. The electric furnace was heated and controlled so that the temperature in the layer became the temperature shown in Table 1. From the top of this reaction tube, methanol / methyl glycolate (weight ratio) =
3/7 glycolic acid ester solution 8.4 g / hr, and air 79 ml / min and nitrogen gas 187 ml / min
While feeding a mixed gas of the above, a gas phase contact reaction was carried out at the above temperature for 1 hour under normal pressure, and the product passing through the reaction tube was collected in an ice-cooled trap. The reaction product collected in the trap was analyzed by gas chromatography to find that the space-time yield of methyl glycolate was 576 g / l.
-In hr, the conversion rate of methyl glycolate is 90.9%,
The selectivity of methyl glyoxylate was 89.0% and the yield of methyl glyoxylate was 80.1%.

Example 2 [Preparation of catalyst] In Example 1, the catalyst preparation liquid was replaced with water 3
Copper phosphate trihydrate in 0ml _{[Cu 3 (PO 4) 2 ·} 3H 2
O] 14.5 g (33.3 mmol) and ferric phosphate tetrahydrate [FePO ₄ .4H ₂ O] 6.7 g (33 mmo
A catalyst was prepared in the same manner as in Example 1 except that l) was added. The atomic ratio of iron to copper (Fe / Cu) of the obtained catalyst was 0.3 by fluorescent X-ray. [Production of Methyl Glyoxylate] The gas phase catalytic reaction was carried out in the same manner as in Example 1 except that the catalyst was changed to 8 ml of the above catalyst. The results are shown in Table 1.

Example 3 [Preparation of catalyst] In Example 1, the catalyst preparation liquid was replaced with water 3
Copper phosphate trihydrate in 0ml _{[Cu 3 (PO 4) 2 ·} 3H 2
O] 14.5 g (33.3 mmol) and ferric phosphate tetrahydrate [FePO ₄ .4H ₂ O] 13.4 g (60 mmo
A catalyst was prepared in the same manner as in Example 1 except that l) was added. The atomic ratio of iron to copper (Fe / Cu) in the obtained catalyst was 0.6. [Production of Methyl Glyoxylate] In Example 1, the catalyst was changed to 8 ml of the above catalyst, and the glycolate solution was replaced with methanol / methyl glycolate (weight ratio).
In the same manner as in Example 1 except that 11.9 g / hr of the glycolic acid ester solution of = 1 was fed, the gas phase catalytic reaction was performed. The results are shown in Table 1.

Example 4 [Preparation of catalyst] In Example 1, the catalyst preparation liquid was replaced with water 3
Copper phosphate trihydrate in 0ml _{[Cu 3 (PO 4) 2 ·} 3H 2
O] 14.5 g (33.3 mmol) and ferric phosphate tetrahydrate [FePO ₄ .4H ₂ O] 22.3 g (100 mm
The catalyst was prepared in the same manner as in Example 1 except that the solution containing ol) was added. The atomic ratio of iron to copper (Fe / Cu) in the obtained catalyst was 1.0. [Production of Methyl Glyoxylate] The gas phase catalytic reaction was carried out in the same manner as in Example 1 except that the catalyst was changed to 8 ml of the above catalyst. The results are shown in Table 1.

Example 5 In Example 1, the catalyst preparation solution was prepared by adding 8.7 g of copper phosphate trihydrate [Cu ₃ (PO ₄ ) ₂ .3H ₂ O] to 30 ml of water.
(20 mmol) and ferric phosphate tetrahydrate [FePO ₄ ·
4H ₂ O] 22.3 g (100 mmol) was added, and the catalyst was prepared in the same manner as in Example 1 except that the liquid was changed. The atomic ratio of iron to copper of the obtained catalyst (Fe / C
u) was 1.7. [Production of Methyl Glyoxylate] The gas phase catalytic reaction was carried out in the same manner as in Example 1 except that the catalyst was changed to 8 ml of the above catalyst. The results are shown in Table 1.

Comparative Example 1 [Preparation of catalyst] In Example 1, the catalyst preparation liquid was water 3
Ferric phosphate tetrahydrate [FePO ₄ .4H ₂ O] in 0 ml
A catalyst was prepared in the same manner as in Example 1 except that the liquid added was 44.6 g (200 mmol). [Production of Methyl Glyoxylate] The gas phase catalytic reaction was carried out in the same manner as in Example 1 except that the catalyst was changed to 8 ml of the above catalyst. The results are shown in Table 1.

[0028]

[Table 1]

Example 6 [Preparation of catalyst] A catalyst was prepared in the same manner as in Example 1. [Production of Methyl Glyoxylate] In the same manner as in Example 1 except that the catalyst was changed to 8 ml of the above catalyst and methyl glycolate 6.0 g / hr was fed instead of the glycolate ester solution. A gas phase contact reaction was performed. The results are shown in Table 2.

Example 7 [Preparation of catalyst] A catalyst was prepared in the same manner as in Example 2. The atomic ratio of iron to copper (Fe / Cu) in the obtained catalyst was 0.
It was 3. [Production of Methyl Glyoxylate] The gas phase catalytic reaction was carried out in the same manner as in Example 6 except that the catalyst was changed to 8 ml of the above catalyst. The results are shown in Table 2.

Example 8 [Preparation of catalyst] A catalyst was prepared in the same manner as in Example 3. The atomic ratio of iron to copper (Fe / Cu) in the obtained catalyst was 0.
It was 6. [Production of Methyl Glyoxylate] The gas phase catalytic reaction was carried out in the same manner as in Example 6 except that the catalyst was changed to 8 ml of the above catalyst. The results are shown in Table 2.

Example 9 [Preparation of catalyst] A catalyst was prepared in the same manner as in Example 4. The atomic ratio of iron to copper (Fe / Cu) of the obtained catalyst was 1.
It was 0. [Production of Methyl Glyoxylate] The gas phase catalytic reaction was carried out in the same manner as in Example 6 except that the catalyst was changed to 8 ml of the above catalyst. The results are shown in Table 2.

Example 10 A catalyst was prepared in the same manner as in Example 5. The atomic ratio of iron to copper (Fe / Cu) of the obtained catalyst was 1.7. [Production of Methyl Glyoxylate] The gas phase catalytic reaction was carried out in the same manner as in Example 6 except that the catalyst was changed to 8 ml of the above catalyst. The results are shown in Table 2.

Comparative Example 2 [Preparation of catalyst] A catalyst was prepared in the same manner as in Comparative Example 1. [Production of Methyl Glyoxylate] The gas phase catalytic reaction was carried out in the same manner as in Example 6 except that the catalyst was changed to 8 ml of the above catalyst. The results are shown in Table 2.

Example 11 In Example 1, the catalyst preparation solution was mixed with 10 ml of water and 85
% 11.2 g (97 mmol) of phosphoric acid in a solution of copper nitrate trihydrate [Cu (NO ₃ ) ₂ .3H ₂ O] 24.2 g (1
00 mmol) and ferric nitrate nonahydrate [Fe (NO ₃ ) ₃
· 9H ₂ O] 12.1 g (30 mmol) addition it was changed to a solution obtained by heating dissolved by adding was prepared in the same manner as catalyst as in Example 1. The atomic ratio of iron to copper (Fe / Cu) of the obtained catalyst was 0.3. [Production of Methyl Glyoxylate] The gas phase catalytic reaction was carried out in the same manner as in Example 6 except that the catalyst was changed to 8 ml of the above catalyst. The results are shown in Table 2.

Example 12 [Preparation of catalyst] In Example 1, the catalyst preparation liquid was replaced with water 3
Copper phosphate trihydrate in 0ml _{[Cu 3 (PO 4) 2 ·} 3H 2
O] 14.5 g (33.3 mmol) and cobalt phosphate (II) Hachimizushio _{[Co 3 (PO 4) 2 ·} 8H 2 O ] 1.7
A catalyst was prepared in the same manner as in Example 1 except that the liquid added was 1 g (3.34 mmol). The obtained catalyst had an atomic ratio of cobalt to copper (Co / Cu) of 0.1.
Met. [Production of Methyl Glyoxylate] The gas phase catalytic reaction was carried out in the same manner as in Example 6 except that the catalyst was changed to 8 ml of the above catalyst. The results are shown in Table 2.

Example 13 [Preparation of catalyst] In Example 1, the catalyst preparation liquid was replaced with water 3
Copper phosphate trihydrate in 0ml _{[Cu 3 (PO 4) 2 ·} 3H 2
O] 14.5 g (33.3 mmol) and manganese phosphate (II) pentahydrate _{[Mn 3 (PO 4) 2 ·} 5H 2 O ] 1.4
A catalyst was prepared in the same manner as in Example 1 except that 9 g (3.35 mmol) was added. The obtained catalyst had an atomic ratio of manganese to copper (Mn / Cu) of 0.1.
Met. [Production of Methyl Glyoxylate] The gas phase catalytic reaction was carried out in the same manner as in Example 6 except that the catalyst was changed to 8 ml of the above catalyst. The results are shown in Table 2.

[0038]

[Table 2]

Example 14 [Preparation of catalyst] A catalyst was prepared in the same manner as in Example 2. The atomic ratio of iron to copper (Fe / Cu) in the obtained catalyst was 0.
It was 3. [Production of Ethyl Glyoxylate] The same as in Example 6 except that the catalyst was changed to 8 ml of the above catalyst and ethyl glycolate 6.7 g / hr was fed instead of the glycolate ester solution. A gas phase contact reaction was performed. The results are shown in Table 3.

Comparative Example 3 [Preparation of catalyst] A catalyst was prepared in the same manner as in Comparative Example 1. [Production of ethyl glyoxylate] In Example 14,
Example 1 except that the catalyst was changed to 8 ml of the above catalyst
The gas phase contact reaction was carried out in the same manner as in 4. The results are shown in Table 3.

[0041]

[Table 3]

[0042]

Industrial Applicability According to the present invention, it is possible to solve the problems that the known method for producing a glyoxylic acid ester has with respect to the conversion of raw materials, the selectivity of a target product, the production rate (space-time yield) of the target product, and the like. You can That is, a highly active catalyst that can be easily prepared is charged into a normal reactor, and the glycolic acid ester and molecular oxygen are reacted in the gas phase to increase the conversion rate of the glycolic acid ester, and then the glyoxylic acid ester is obtained. Can be produced with high selectivity (that is, with high yield) and with high production rate (space-time yield).

Front Page Continuation (72) Inventor Koho Fukuda 5 1978, Kogushi, Ube City, Ube City, Yamaguchi Prefecture Ube Laboratory Ltd.

Claims (1)

[Claims] 1. A method for producing a glyoxylic acid ester, which comprises reacting a glycolic acid ester with molecular oxygen in a gas phase in the presence of an unsupported copper phosphate catalyst.