JP3176895B2 - Method for producing α-oxoaldehyde - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing α-oxo aldehyde by a gas phase reaction and a method for producing α-oxo carboxylic acid ester by a gas phase reaction.

Glyoxal and pyruvaldehyde (methylglyoxal), which are typical α-oxo aldehydes, are used as various products such as fiber processing agents, paper processing agents, soil hardening agents, or as intermediate raw materials for various products. It is an industrially useful compound. Also, a typical α-
Glyoxylate, which is an oxocarboxylate, is an industrially useful compound. For example, sodium polyacetal carboxylate obtained from a polymer of glyoxylate is used as a builder such as a detergent. Alternatively, for example, glyoxylic acid obtained by hydrolyzing glyoxylate is a very useful compound as an intermediate material for various products such as pharmaceuticals, cosmetics, fragrances, and agricultural chemicals.

[0003]

2. Description of the Related Art A method for producing α-oxoaldehyde by oxidative dehydrogenation of an alkylene glycol in the presence of a silver catalyst has been known. For example, oxidative dehydrogenation of ethylene glycol, which is the simplest alkylene glycol, using metallic silver (silver crystal) having a particle diameter in the range of 0.1 mm to 2.5 mm as a catalyst,
A method for obtaining glyoxal at a yield of the order of 60% (Japanese Patent Publication No. Sho 61)
54011) and a method of obtaining glyoxal in an yield of 82% as an example by oxidative dehydrogenation using metallic silver modified with a phosphorus-containing compound as a catalyst (Japanese Patent Application Laid-Open No. 58-38227). JP-A-58-59
No. 933, Chinese Patent No. 85100530, Catalyst
sis Letters, 36 (1996) 207-214). A method of obtaining glyoxal with a yield of 84% by adding a phosphorus-containing compound vaporized to ethylene glycol and then performing oxidative dehydrogenation using granular metallic silver as a catalyst (Japanese Patent Application Laid-Open No. 3-232835). Or, by oxidatively dehydrogenating ethylene glycol using a catalyst in which metallic silver is supported on a carrier such as silicon carbide or silicon nitride,
A method for obtaining glyoxal at a yield of 70% (Japanese Patent Publication No.
No. 32648) is also known. In these methods, since the polymerizability of glyoxal is extremely high, a large amount of water (1
(3.5 times by mole), the produced glyoxal is taken out, for example, in the form of a 40% by weight aqueous solution, and commercialized.

However, none of the above-mentioned conventional methods can be said to be methods capable of producing glyoxal at a sufficiently high yield and high concentration.

[0005] On the other hand, the inventors of the present application have previously proposed a method for producing an α-oxocarboxylic acid ester from α-oxoaldehyde using α-oxoaldehyde and an alcohol as raw materials and oxidizing using an oxygen and a catalyst. A method for esterification has been proposed (Japanese Patent Application Laid-Open No. Hei 9-118650). In the method, for example, glyoxal 40, which is the simplest commercially available α-oxoaldehyde, is used.
By heating a weight% aqueous solution, gaseous glyoxal is obtained as a raw material. However, since glyoxal has extremely high polymerizability, it may be industrially difficult to vaporize glyoxal and supply it to the reaction system. Under the condition that water coexists in the reaction system, α
Since glyoxylate as oxocarboxylate is obtained, the glyoxylate may be hydrolyzed and the yield may be reduced.

[0006]

That is, the above-mentioned conventional method has a problem that α-oxoaldehyde cannot be produced in a sufficiently high yield. Also,
The above-mentioned conventional method has a problem that it is not possible to stably obtain a higher concentration α-oxoaldehyde solution or gas. Further, due to these problems of the above-mentioned conventional method, there is a further problem that α-oxocarboxylic acid esters cannot be produced in high yield.

[0007] The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to produce α-oxoaldehyde in a higher yield than before, and to further increase the concentration of α-oxoaldehyde. An object of the present invention is to provide a method capable of stably obtaining an α-oxoaldehyde solution or gas.
Another object of the present invention is to provide a method for producing an α-oxocarboxylic acid ester in a higher yield than before.

[0008]

Means for Solving the Problems In order to achieve the above objects, the inventors of the present application have made intensive studies on a method for producing α-oxoaldehyde and a method for producing α-oxocarboxylic acid ester. As a result, by subjecting the alkylene glycol to gas phase oxidation in the presence of the alcohol (a), oxygen and a catalyst, α-oxoaldehyde can be produced at a higher yield than before, and moreover, at a higher yield than before. Concentration of α-oxoaldehyde solution or gas can be obtained stably, and the α-oxoaldehyde solution or gas obtained by the method can be obtained stably.
-Gas-phase oxidation of oxo aldehyde and, for example, alcohol (b) in the presence of oxygen and a catalyst to give α-
It has been confirmed that an oxocarboxylic acid ester can be produced in a higher yield than before, and the present invention has been completed.

[0009] That is, the manufacturing method of α- oxoaldehyde of the present invention, in order to solve the above problems, an alkylene glycol, in vapor phase oxidation in the presence of oxygen and a catalyst (a), an alkylene glycol It is characterized by the coexistence of alcohol (a) excluding .

In order to solve the above-mentioned problems, the method of the present invention for producing α-oxoaldehyde has a molar ratio of alkylene glycol to alcohol (a) of from 1/100 to 5/1.
Is within the range. Α-O of the present invention
The production method of xoxoaldehyde solves the above problems.
For example, the catalyst (a) is a metal catalyst and / or an oxide catalyst.
It is characterized by having.

[0011] The method of producing α- oxo carboxylic acid esters of the present invention, in order to solve the above problems, an alkylene glycol, in vapor phase oxidation in the presence of oxygen and a catalyst (a), alkylene After obtaining α-oxoaldehyde in the coexistence of alcohol (a) excluding glycol, the α-oxoaldehyde and the alcohol (b) or olefin are converted in the presence of oxygen and a catalyst (b). It is characterized by gas phase oxidation.

In order to solve the above-mentioned problems, the method for producing an α-oxocarboxylic acid ester of the present invention is characterized in that the alcohol (a) and the alcohol (b) are the same compound.

In order to solve the above-mentioned problems, the method for producing an α-oxocarboxylic acid ester of the present invention is characterized in that the alcohol (a) is obtained by gas-phase oxidation of α-oxoaldehyde and alcohol (b). Characterized in that it contains unreacted alcohol (b) contained in the reaction gas obtained. Α of the present invention
The method for producing an oxocarboxylic acid ester has the above problems.
In order to solve the problem, the catalyst (a) is a metal catalyst and / or
An oxide catalyst, wherein the catalyst (b) contains a phosphorus-containing inorganic oxide.
It is characterized by being a catalyst.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The process for producing α-oxoaldehyde according to the present invention is a process for subjecting an alkylene glycol to gas-phase oxidation in the presence of an alcohol (a), oxygen (molecular oxygen) and a catalyst. In addition, the method for producing an α-oxocarboxylic acid ester according to the present invention comprises the step of reacting the α-oxoaldehyde obtained by the above method with an alcohol (b) or an olefin in the presence of oxygen (molecular oxygen) and a catalyst. It is a gas phase oxidation, that is, a method of oxidative esterification.
In the following description, for the sake of convenience, a reaction for obtaining α-oxoaldehyde by vapor-phase oxidation of alkylene glycol to obtain α-oxoaldehyde is referred to as a first-stage reaction, and a reaction for obtaining α-oxocarboxylic acid ester by oxidatively esterifying α-oxoaldehyde. Is referred to as a second-stage reaction. Further, the catalyst used for the gas phase oxidation of alkylene glycol is referred to as catalyst (a), and the catalyst used for oxidative esterification of α-oxoaldehyde is referred to as catalyst (b).
It is written.

The alkylene glycol used as a raw material is not particularly limited, but is preferably a compound which vaporizes at normal pressure (atmospheric pressure).

[0016]

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1,2-diol represented by the formula (wherein, R represents a hydrogen atom or an organic residue) is more preferred. As the 1,2-diol, specifically, for example, ethylene glycol in which the substituent represented by R is a hydrogen atom;
The substituent represented by R is a saturated aliphatic hydrocarbon group having 1 to 4 carbon atoms, for example, propylene glycol, 1,2-butanediol, 1,2-pentanediol, 1,2-hexanediol, 3-methyl -1,2-butanediol, 3-methyl-1,2-pentanediol, 4-methyl-1,2-pentanediol and the like; an unsaturated aliphatic hydrocarbon having a substituent represented by R having 2 to 3 carbon atoms Groups such as 1,2-dihydroxy-3-butene, 1,2-dihydroxy-3-pentene, 1,2-dihydroxy-4-
Pentene and the like; examples of the substituent represented by R are aromatic hydrocarbon groups, such as 1-phenyl-1,2-dihydroxyethane; and the like, but are not particularly limited thereto.
Of the 1,2-diols exemplified above, ethylene glycol and propylene glycol are particularly preferred. That is,
1,2-diols having 2 to 3 carbon atoms are particularly preferred as the alkylene glycol.

The alcohol (a) to be used in the first-stage reaction, that is, the alcohol (a) to be supplied (entrained) to the reaction system, is specifically, for example, methanol, ethanol, or the like.
Industrially easily available, such as 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutanol, t-butanol, hexanol, cyclohexanol, octanol, 2-ethylhexanol, lauryl alcohol, stearyl alcohol, etc. Examples thereof include aliphatic alcohols having 1 to 18 carbon atoms, but are not particularly limited. One of these alcohols may be used alone, or two or more of them may be used in combination. Among the alcohols exemplified above, aliphatic alcohols having 1 to 4 carbon atoms, such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutanol and t-butanol, are more preferable. Is more preferred.

Alcohol to alkylene glycol
The ratio of (a), that is, the molar ratio between the alkylene glycol and the alcohol (a) may be set according to the combination of the two and the reaction conditions, and is not particularly limited. / 1, more preferably in the range of 1/50 to 5/1, and particularly preferably in the range of 1/25 to 3/1. By setting the molar ratio of both to be within the above range, α-oxoaldehyde can be produced with a higher yield. Further, by decreasing the ratio of the alcohol (a) to the alkylene glycol within the above range, it is possible to stably obtain an α-oxoaldehyde solution or gas having a higher concentration than before.

The catalyst (a) used in the first-stage reaction includes:
For example, a metal catalyst such as metallic silver; CuO—ZnO / α-A
Various oxide catalysts such as l ₂ O ₃ and Ag ₂ O—SiO ₂ —ZnO; and the like, but are not particularly limited. More specifically, for example, metallic silver (electrolytic silver), Metallic silver (electrolytic silver) modified with a phosphorus-containing compound such as phosphoric acid is preferred. As the shape of the catalyst (a), specifically, for example, various shapes such as a granular shape and a net shape are suitable, but are not particularly limited. The particle size of the catalyst (a) in the case of, for example, a granular shape is not particularly limited, but is preferably in the range of 8 mesh to 60 mesh. The method for preparing the catalyst (a) is not particularly limited. For example, as the granular metallic silver, it is convenient to use a commercially available metallic silver having a particle diameter adjusted to a predetermined size. is there.

The first-stage reaction is a reaction for obtaining gaseous α-oxoaldehyde from alkylene glycol, and can be carried out according to various known methods for producing α-oxoaldehyde. The reactor (equipment) used for the first-stage reaction is
It suffices if a structure capable of performing gas phase oxidation is provided. For example, a fixed bed flow type gas phase reactor is suitable, but is not particularly limited. Then, a fixed bed flow type gas phase reactor is used as the reactor, and granular silver metal is used as a catalyst.
When used as (a), the catalyst (a) is used in such a manner that the particle diameter of the catalyst (a) is larger on the gas outlet side than on the gas inlet side in a fixed bed flow type gas phase reactor. It is particularly preferable to fill (lamination) into the film. More specifically, for example, a catalyst charged on the gas inlet side in a reactor
The particle size of (a) is more preferably in the range of 16 mesh to 60 mesh, and even more preferably in the range of 20 mesh to 30 mesh. On the other hand, the particle size of the catalyst (a) charged on the gas outlet side in the reactor is more preferably in the range of 8 mesh to 30 mesh, and further preferably in the range of 10 mesh to 20 mesh. Thus, by charging (stacking) the catalyst (a) into the fixed bed flow type gas phase reactor,
The yield of α-oxoaldehyde can be further improved.

As the oxygen to be used for the first-stage reaction, air or a mixed gas obtained by diluting oxygen gas or air with an inert gas such as nitrogen gas or helium gas can be used in addition to oxygen gas. And industrially, it is more preferable to use air or a mixed gas of air and an inert gas as an oxygen source because it is inexpensive.

The gas to be subjected to the first-stage reaction, that is, a gas containing alkylene glycol and alcohol (a)
The composition of the supply gas (a) is not particularly limited, but the proportion of the alkylene glycol, oxygen (oxygen gas) and alcohol (a) in the supply gas (a) is as follows:
In this order, it is more preferably 1% by volume to 10% by volume, 1% by volume to 10% by volume, and 0.01% by volume to 30% by volume (the remainder is an inert gas and the total is 100% by volume). Preferably, in this order, 3% by volume to 8% by volume, 3% by volume
More preferably, it is from about 8% by volume to about 8% by volume and from about 0.01% by volume to about 20% by volume. If the composition of the feed gas (a) is out of the above range, there is a possibility that α-oxoaldehyde cannot be produced at a higher yield than before. For example, if the proportion of the alkylene glycol is too large, a side reaction such as combustion tends to occur, so that it may be impossible to control the first-stage reaction.

The supply gas (a) may contain water (steam) if necessary. When the supply gas (a) contains water, the proportion of the water is more preferably 30% by volume or less, further preferably 10% by volume or less. The method for preparing the supply gas (a) is not particularly limited.

Further, in order to further improve the yield of α-oxoaldehyde, a phosphorus-containing compound is allowed to coexist in the reaction system, that is, if the vaporized phosphorus-containing compound is added to the feed gas (a) as necessary. Can be added.
Specific examples of the phosphorus-containing compound include, for example, organic phosphorus-containing compounds such as triethyl phosphite and diethyl phosphate. It is not limited. The addition amount of the phosphorus-containing compound is not particularly limited, but it is more preferable that the ratio of phosphorus to the alkylene glycol be 1% by weight or less, and 40 pp.
It is more preferable that the concentration be not less than m and not more than 100 ppm. When metal silver modified with a phosphorus-containing compound is used as the catalyst (a), it is not necessary to add the phosphorus-containing compound to the reaction system.

The reaction conditions of the first-stage reaction may be set so as to control the first-stage reaction in accordance with the composition of the feed gas (a), the type of the catalyst (a), the configuration of the reactor, and the like. Although not particularly limited, for example, the reaction temperature is 40
It is more preferably in the range of 0 ° C to 700 ° C, and 500 ° C to 6 ° C.
More preferably, the temperature is in the range of 50 ° C. The space velocity (S
V) is more preferably in a range of 5,000hr ^-1 ~800,000hr ^-1, 10,000hr ^-1 ~200,0
The range of 00 hr ^-1 is more preferable. Space velocity is 5,
If it is lower than 000 hr ⁻¹ , side reactions such as combustion may easily occur. The space velocity is 800,
If it is higher than 000 hr ⁻¹ , the conversion of the alkylene glycol may decrease.

For example, metallic silver as the catalyst (a) is charged into a fixed-bed flow-type gas phase reactor, and the feed gas (a) containing ethylene glycol as the alkylene glycol is fed to the former stage under the above composition range and reaction conditions. When reacted, glyoxal as α-oxoaldehyde is obtained in a yield of about 80% to 95% with a conversion of ethylene glycol of about 99% to 100%. The space velocity is the supply amount of the supply gas (a) per hour (L / hr)
Is divided by the amount (L) of the catalyst (a) used in the first-stage reaction, and is a value converted into a standard state (NTP).

By performing the above-mentioned first-stage reaction, a reaction gas containing gaseous α-oxoaldehyde is obtained. The proportion of α-oxoaldehyde in the reaction gas is represented by the concentration of α-oxoaldehyde in a solution obtained by condensing the reaction gas as it is by appropriately setting the reaction conditions of the first-stage reaction, and is 45% by weight or less. It can be in the range of 80% by weight, or even in the range of 50% to 70% by weight. That is, α-oxoaldehyde can be produced at a higher yield than before, and an α-oxoaldehyde solution or gas having a higher concentration than before can be stably obtained. In addition, α-
Oxaldehyde solution can be easily obtained,
Costs for transportation and storage can be reduced. α-
The method for collecting and isolating oxoaldehyde is not particularly limited, and various known methods can be employed. Further, the reaction gas containing α-oxoaldehyde can be used as it is as a raw material for the subsequent reaction without isolating the α-oxoaldehyde.

When the 1,2-diol represented by the above general formula (1) is used as the alkylene glycol, the general formula (2)

[0030]

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(Wherein, R represents a hydrogen atom or an organic residue) to obtain α-oxoaldehyde. The α
-Oxaldehyde, specifically, for example, R
Glyoxal wherein the substituent represented by is a hydrogen atom;
Is a saturated aliphatic hydrocarbon group having 1 to 4 carbon atoms, for example, pyruvaldehyde, 2-oxobutanal, 2-oxopentanal, 2-oxohexanal, 3-methyl-2-oxobuta Nal, 3-methyl-2-oxopentanal, 4-methyl-2-oxopentanal, and the like; the substituent represented by R is an unsaturated aliphatic hydrocarbon group having 2 to 3 carbon atoms, for example, 2-oxo -3-
Butenal, 2-oxo-4-pentenal and the like; 2-oxo-3-pentenal and the like; the substituent represented by R is an aromatic hydrocarbon group, for example, 2-phenyl-2-oxoethanal and the like. However, there is no particular limitation. According to the method of the present invention, glyoxal is obtained from ethylene glycol, and pyruvaldehyde (methylglyoxal) is obtained from propylene glycol.

The reaction gas containing α-oxoaldehyde contains formaldehyde, carbon monoxide, carbon dioxide, water, and the like generated as a by-product such as combustion. A part of the alcohol (a) to be added is lost by a side reaction such as combustion.
Is recovered and approximately 10% by weight is converted to formaldehyde.

The detailed reason why α-oxoaldehyde is stabilized by the coexistence of alcohol (a) in the first-stage reaction, that is, the detailed reason why α-oxoaldehyde can be produced in a higher yield than before. Although the reason is not clear, α-oxoaldehyde is alcohol
This is presumed to be due to the formation of hemiacetal with (a).

As the alcohol (b) to be subjected to the latter-stage reaction, specifically, for example, the above-mentioned alcohol (a)
Aromatic alcohols such as phenol and benzyl alcohol; and the like, but are not particularly limited. These alcohols may be used alone,
If necessary, two or more types may be used in combination. Among the alcohols exemplified above, methanol, ethanol,
Aliphatic alcohols having 1 to 4 carbon atoms, such as 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutanol and t-butanol, are more preferred, and methanol is even more preferred.

Then, the alcohol (a) is replaced with an alcohol
(b) alcohol (a) so that it can serve as
It is most preferred that the alcohol and the alcohol (b) are the same compound. That is, the alcohol used as the alcohol (b) in the latter reaction is replaced with the alcohol (a) in the former reaction.
It is most preferred to use In this case, there is no need to remove the alcohol (a) from the α-oxo aldehyde prior to performing the subsequent reaction. Further, after collecting (separating) products such as α-oxocarboxylic acid ester from the reaction gas obtained in the latter reaction, the uncollected alcohol contained in the gas is removed by the alcohol (a) in the former reaction. Can be used as it is. Therefore, the α-oxocarboxylic acid ester can be produced more easily.

As the above-mentioned olefin to be subjected to the latter-stage reaction, specifically, for example, ethylene, propylene, 1-
Examples thereof include olefins having 2 to 4 carbon atoms such as butene, 2-butene, and isobutene, but are not particularly limited. These olefins may be used alone,
If necessary, two or more types may be used in combination.

Alcohol for α-oxoaldehyde
The ratio of (b) or olefin (hereinafter simply referred to as alcohol (b)), that is, the molar ratio of α-oxoaldehyde to alcohol (b) may theoretically be equivalent (1/1). May be set according to the combination of the two, the reaction conditions, and the like, and there is no particular limitation.

The catalyst (b) used in the latter reaction includes:
For example, a metal catalyst such as metallic silver, various oxide catalysts, and the like can be mentioned. Among them, a catalyst containing a phosphorus-containing inorganic oxide is preferable. Various compounds can be used as the phosphorus-containing inorganic oxide, and are not particularly limited, but metal phosphates and phosphorus-containing heteropoly acids are more preferable. Incidentally, a mixture of a metal phosphate and a phosphorus-containing heteropolyacid can also be used as the catalyst (b).

The metal constituting the metal phosphate is not particularly limited as long as it is a metal capable of forming a phosphate. As the metal, specifically,
For example, alkali metals, alkaline earth metals, B, Al,
Ti, V, Cr, Mn, Fe, Co, Ni, Zn, Z
r, Mo, Pd, Ag, Cd, Sn, Pb and the like. As for these metals, only one kind may be contained in the metal phosphate, or two or more kinds may be contained in the metal phosphate. That is, the metal phosphate may include two or more metals. Furthermore, two or more metal phosphates can be used in combination. That is, the metal phosphate as the catalyst (b) includes a metal phosphate containing one kind of metal; a metal phosphate containing two or more kinds of metals;
A mixture containing two or more of these metal phosphates;
Is included. Further, different metal phosphates may be filled (laminated) as the catalyst (b) on the gas inlet side and the gas outlet side in the reactor used for the latter-stage reaction.

The molar ratio of the metal to phosphorus in the metal phosphate may be outside the stoichiometric ratio of the orthophosphate, but is preferably closer to the stoichiometric ratio.
More preferably, it is in the range of 1 / 0.5 to 1/2.

The method for preparing the metal phosphate is not particularly limited. For example, a coprecipitation method in which the metal phosphate is coprecipitated from an aqueous solution obtained by mixing and dissolving a metal salt and a phosphoric acid source. Kneading method in which a metal salt and a phosphoric acid source are mixed to form a slurry, and then kneaded to obtain a metal phosphate; Alternatively, a commercially available reagent or the like can be used as the metal phosphate. Examples of the metal salt include, but are not particularly limited to, metal nitrates, carbonates, oxalates, hydroxides, and chlorides. One of these metal salts may be used alone, or two or more thereof may be used in combination.
As the phosphoric acid source, specifically, for example, orthophosphoric acid, ammonium phosphate, ammonium monohydrogen phosphate,
Phosphates such as ammonium dihydrogen phosphate may be mentioned, but are not particularly limited. These sources of phosphate
Only one type may be used, or two or more types may be used in combination. Furthermore, the combination of the metal salt and the phosphoric acid source is not particularly limited, and various combinations can be adopted.

Depending on the type and composition of the metal phosphate, the metal phosphate is dried in air at a temperature in the range of 100.degree. C. to 120.degree.
In air within the range, more preferably at a temperature of 400 ° C to 80 ° C.
It is more preferable to perform calcination in air at a temperature within the range of 0 ° C. and, if necessary, to carry out molding or pretreatment for adjusting the particle diameter. The metal phosphate can be used as the catalyst (b) without performing the above pretreatment.

Furthermore, the metal phosphate is more preferably used as a catalyst (b) in the form of a mixture to which an inorganic oxide has been added. As the inorganic oxide, specifically,
For example, silica, titania, zirconia, niobium oxide,
Examples include diatomaceous earth, but are not particularly limited. The titania may be of the anatase type,
It may be a rutile type. One kind of these inorganic oxides may be used, or two or more kinds may be used in combination. The amount of the inorganic oxide added to the metal phosphate depends on the type and composition of the metal phosphate and the type of the inorganic oxide,
The proportion of the inorganic oxide in the total amount of both is 1% by weight or more.
90% by weight, more preferably 10% by weight to 60% by weight.
It may be within the range of weight%. In addition, even if the metal phosphate is not made into the above-mentioned mixture,
(b) can be used.

The phosphorus-containing heteropolyacid is not particularly limited, but has the following general formula: H _a PM ₁₂ O ₄₀ .nH ₂ O (where M is at least one selected from the group consisting of tungsten, molybdenum and vanadium) A Keggin-type heteropolyacid represented by one kind of metal atom, a is a numerical value determined by M, and n is 0 or a positive number) is particularly preferable since it has excellent catalytic performance.

Compounds in which some or all of the hydrogen atoms constituting the Keggin-type heteropolyacid are replaced by metal atoms such as alkali metal atoms, alkaline earth metal atoms, transition metal atoms, etc., ie, the following general formula H _(ab) M ′ _b PM ₁₂ O ₄₀ .nH ₂ O (wherein M represents at least one metal atom selected from the group consisting of tungsten, molybdenum and vanadium, and M ′ represents an alkali metal atom or an alkaline earth metal) Represents a metal atom such as an atom or a transition metal atom, a is a numerical value determined by M, b is any numerical value satisfying 0 <b ≦ a, and n is 0 or a positive number. Acid salts can also be used. The method for preparing a Keggin-type heteropolyacid or a heteropolyacid salt, that is, the method for preparing the phosphorus-containing heteropolyacid is not particularly limited,
Various known methods can be employed.

Depending on the type and composition of the phosphorus-containing heteropolyacid, the phosphorus-containing heteropolyacid is dried in air, and then subjected to a pretreatment of firing in air at a temperature higher than the reaction temperature of the subsequent reaction. Is more preferable. The phosphorus-containing heteropolyacid can be used as the catalyst (b) without performing the above pretreatment.

In addition, the phosphorus-containing heteropolyacid is more preferably used as the catalyst (b) while supported on a carrier. As the carrier, specifically, for example, silica,
Examples include titania, zirconia, niobium oxide, and diatomaceous earth, but are not particularly limited, as long as they do not adversely affect the subsequent reaction and are stable to the phosphorus-containing heteropolyacid. The above titania may be of an anatase type or a rutile type. These carriers may be used alone or in combination of two or more. As a supporting method for supporting the phosphorus-containing heteropolyacid on the carrier, specifically, for example, a so-called kneading method or an impregnating supporting method can be adopted.
There is no particular limitation. The phosphorus-containing heteropolyacid can be used as a catalyst (b) without being supported on a carrier.

The latter reaction is a reaction for obtaining gaseous α-oxocarboxylic acid ester from α-oxoaldehyde, and can be carried out according to various known oxidation reactions and oxidative esterification reactions. The reactor to be subjected to the second-stage reaction may have a structure capable of oxidative esterification. For example, a fixed bed flow type gas phase reactor is suitable, but is not particularly limited.

As the oxygen to be supplied to the second-stage reaction, in addition to oxygen gas, air or a mixed gas obtained by diluting oxygen gas or air with an inert gas such as nitrogen gas or helium gas can be used. And industrially, it is more preferable to use air or a mixed gas of air and an inert gas as an oxygen source because it is inexpensive.

The gas to be subjected to the second-stage reaction, that is, a gas containing α-oxoaldehyde and alcohol (b) (hereinafter referred to as “gas”)
The composition of the supply gas (b) is not particularly limited, but the ratio of α-oxoaldehyde, oxygen (oxygen gas) and alcohol (b) in the supply gas (b) is as follows:
In this order, it is more preferable to be 1% by volume to 10% by volume, 1% by volume to 10% by volume, and 5% by volume to 50% by volume (the remainder is an inert gas, and the total is 100% by volume). When the composition of the supply gas (b) is out of the above range,
There is a risk that the α-oxocarboxylic acid ester cannot be produced in a higher yield than before, and the alcohol (b)
May be increased. In addition, supply gas (b)
May contain water (steam) generated (by-produced) by the first-stage reaction. The method for preparing the supply gas (b) is not particularly limited.

The reaction conditions for the latter reaction may be set so as to control the latter reaction in accordance with the composition of the feed gas (b), the type of the catalyst (b), the configuration of the reactor, and the like. Although not particularly limited, for example, the reaction temperature is 15
It is more preferably in the range of 0 ° C to 500 ° C, and
More preferably, the temperature is in the range of 00 ° C. The space velocity (S
V) is more preferably in a range of 100hr ^-1 ~10,000hr ^-1, more preferably in a range of 500hr ^-1 ~5,000hr ^-1. The space velocity is a value obtained by dividing the supply amount (L / hr) of the supply gas (b) per hour by the amount (L) of the catalyst (b) used in the subsequent reaction. It is a value converted to state (NTP).

By carrying out the latter-stage reaction, a reaction gas containing a gaseous α-oxocarboxylic acid ester is obtained. That is, it is possible to avoid the disadvantages of the conventional method, for example, the inconvenience that the α-oxocarboxylic acid ester is hydrolyzed by the coexistence of water in the reaction system. Can also be produced in high yields. The method for collecting and isolating the gaseous α-oxocarboxylic acid ester is not particularly limited, and various known methods can be employed. According to the method of the present invention, for example, glyoxal ester is obtained from glyoxal, and pyruvate is obtained from pyruvaldehyde.

The reaction gas containing the α-oxocarboxylic acid ester includes, in addition to unreacted oxygen gas and alcohol (b), formaldehyde, carbon monoxide, carbon dioxide, water, etc. generated by a side reaction such as combustion. Is contained as a by-product.

In the method for producing an α-oxocarboxylic acid ester according to the present invention, the reaction gas containing α-oxoaldehyde obtained in the first-stage reaction can be directly used as a raw material for the second-stage reaction. That is, in the method for producing an α-oxocarboxylic acid ester according to the present invention, the first-stage reaction and the second-stage reaction can be performed continuously. In this case, as the reaction apparatus, for example, a fixed-bed flow-type gas-phase reactor in which a reactor used for the first-stage reaction and a reactor used for the second-stage reaction are in a so-called two-stage connection is preferable. It is not something to be done. And, for example, when using the fixed bed flow type gas phase reactor, the catalyst
After supplying the supply gas (a) to the first-stage reactor filled with (a) to obtain a reaction gas containing α-oxoaldehyde, the reaction gas is supplied by adding an alcohol (b), oxygen, or the like to the reaction gas. gas
(b) is formed, and then the supply gas (b) is passed through a second-stage reactor filled with the catalyst (b) to obtain a reaction gas containing an α-oxocarboxylic acid ester.

As described above, the gaseous α-oxoaldehyde is taken out of the reaction system by continuously performing the first-stage reaction and the second-stage reaction, that is, by continuously combining different gas-phase reactions. Instead, the α-oxocarboxylic acid ester can be produced from the alkylene glycol in substantially one step.

In the case where the first-stage reaction and the second-stage reaction are continuously performed, the reaction gas obtained in the second-stage reaction,
A gas after separating products such as α-oxocarboxylic acid ester from the reaction gas, or a gas containing uncollected alcohol after separating and collecting alcohol from the gas, Reuse (recycle) at least part, more preferably all, of the supply gas (a)
can do. Products such as α-oxocarboxylic acid esters can be easily collected by condensing the reaction gas obtained in the subsequent reaction using a condenser or the like. In this case, the alcohol used in the first-stage reaction (a)
Contains unreacted alcohol (b) contained in the reaction gas obtained in the latter reaction. Therefore, alcohol
When (a) and the alcohol (b) are the same compound, and when the above-mentioned reuse is performed, an α-oxocarboxylic acid ester can be more easily and efficiently produced from an alkylene glycol. . That is, it is not necessary to completely separate the unreacted alcohol (b) when reusing it as part or all of the feed gas (a) for the first-stage reaction, so that the cost for the separation can be reduced.

As described above, the method for producing α-oxoaldehyde according to the present invention is a method in which an alkylene glycol is vapor-phase oxidized in the presence of an alcohol (a), oxygen and a catalyst (a). According to the above method, the alcohol (a)
Since α-oxoaldehyde is stabilized by the coexistence of, there is no need to supply, for example, water to obtain the α-oxoaldehyde. Therefore, according to the above method, α-oxoaldehyde can be produced in a higher yield than before, and moreover, α-oxoaldehyde solution or gas having a higher concentration than before can be stably obtained. it can.

As described above, the α- according to the present invention
The method for producing an oxocarboxylic acid ester is a method in which the α-oxoaldehyde obtained by the above-mentioned production method is vapor-phase oxidized with an alcohol (b) or an olefin in the presence of oxygen and a catalyst (b). According to the above method, the inconvenience of the conventional method can be avoided. That is, there is no need to use a commercially available 40% by weight aqueous solution of glyoxal as a raw material for the second-stage reaction, or to supply a large amount of water to the reaction system when obtaining α-oxoaldehyde by the first-stage reaction. Since inconveniences such as hydrolysis of the α-oxocarboxylic acid ester in the latter-stage reaction can be avoided, the α-oxocarboxylic acid ester can be produced in a higher yield than before.

The method for producing an α-oxocarboxylic acid ester according to the present invention is characterized in that the alcohol (a) is
Unreacted alcohol (b) contained in the reaction gas obtained by vapor-phase oxidation of α-oxoaldehyde and alcohol (b)
This is a method using a gas containing. According to the above method,
For example, a reaction gas obtained in a subsequent reaction, a gas obtained by separating a product from the reaction gas, or an alcohol (b) that has not been collected after separating and collecting alcohol (b) from the gas. ) Can be reused as at least a part, more preferably all, of the feed gas (a) for the first-stage reaction. In this case, the recycled alcohol
(a) contains the unreacted alcohol (b), so that when the alcohol (a) and the alcohol (b) are the same compound and the above-mentioned reuse is carried out, The α-oxocarboxylic acid ester can be simply and efficiently produced from an alkylene glycol.

[0060]

The present invention will be described in more detail with reference to the following Examples and Comparative Examples, but the present invention is not limited thereto. In the following Examples and Comparative Examples, the reaction (first-stage reaction) for obtaining glyoxal (hereinafter, referred to as GLO) as α-oxoaldehyde from ethylene glycol (hereinafter, referred to as EG) as an alkylene glycol, or the first-stage reaction, Then GLO
To obtain methyl glyoxylate (hereinafter, referred to as MGO) as an α-oxocarboxylic acid ester (second-stage reaction).

The reaction gas obtained in the first-stage reaction was collected using water at an ice temperature, and then subjected to an internal standard method under a predetermined condition using high performance liquid chromatography equipped with a differential refractometer detector. Adopted and analyzed its components. That is, unreacted EG contained in the reaction gas and generated GLO were quantified.

The reaction gas obtained in the second-stage reaction is collected using acetonitrile at an ice temperature, and then subjected to high-performance liquid chromatography equipped with a differential refractometer detector;
Using gas chromatography equipped with a FID (Flame Ionization Detector; Flame Ion Detector), the components were analyzed under predetermined conditions using an internal standard method. That is, while the unreacted GLO contained in the reaction gas is quantified by high performance liquid chromatography, the generated MLO contained in the reaction gas is determined by gas chromatography.
GO was quantified.

The conversion, yield and selectivity described in the examples and comparative examples were calculated using the results of the above quantification, using the following equation: EG (mol) reacted = EG (mol) supplied-unreacted EG (mol) EG of reaction (mol) EG conversion (%) = (reacted EG (mol) / supplied EG (mol)) x 100 GLO yield (%) = (GLO (mol) generated in the preceding reaction) / (EG supplied (mol)) x 100 Reacted GLO (mol) = supplied GLO (mol)-unreacted GLO (mol) GLO conversion (%) = (reacted GLO (mol) / supplied GLO (mol) Mol)) × 100 Selectivity of MGO (%) = (MGO (mol) produced / GLO reacted (mol)) × 100 MGO yield (%) based on EG = (MG produced)
O (mol) / supplied EG (mol)) × 100.

Example 1 GLO was obtained from EG by carrying out the first-stage reaction. 12m inner diameter as a reaction tube (pre-reactor)
The reaction tube was filled with 15 g of metallic silver (manufactured by Yokohama Metal Co., Ltd .; electrolytic silver having a particle size of 20 to 30 mesh) as a catalyst (a) using a SUS pipe having a diameter of 20 m. Further, an evaporator for heating the supply gas (a) supplied to the reaction tube to a predetermined temperature was attached to the gas inlet side of the reaction tube. Further, a heat insulating material was wound around the outside of the reaction tube to keep the temperature of the reaction tube constant, so that the temperature (reaction temperature) of the catalyst layer during the first-stage reaction was maintained at a predetermined temperature. That is, the inside of the reaction tube was kept warm so that the first-stage reaction proceeded under conditions almost equal to the adiabatic reaction.

The proportions of EG, oxygen, methanol as the alcohol (a), and water in the feed gas (a) were 4.0% by volume, 4.8% by volume, 3.0% by volume, and 0% by volume, respectively. % (The remainder is nitrogen gas and the total is 100% by volume, hereinafter referred to as nitrogen gas balance). Further, triethyl phosphite as a phosphorus-containing compound was added to the supply gas (a) so that the ratio of phosphorus to EG was 60 ppm.
Was added so that

Then, the supply gas (a) having the above composition was continuously supplied to the reaction tube at a space velocity (SV) of 45,000 hr ^-1 to perform a first-stage reaction. Reaction temperature,
That is, the temperature of the catalyst layer reached 570 ° C. The main reaction conditions are summarized in Table 1.

The components of the obtained reaction gas were analyzed by the above method. As a result, the conversion rate of EG was 100% and GL
The yield of O was 88%. The results are summarized in Table 3.

Example 2 The composition of the supply gas (a) was changed to EG
The first-stage reaction was carried out under the same conditions as in Example 1 except that the volume was changed to 4.0% by volume, 4.8% by volume of oxygen, 4.0% by volume of methanol, and 0% by volume of water (nitrogen gas balance). Was. The temperature of the catalyst layer reached 565 ° C. The main reaction conditions are summarized in Table 1. As a result, the conversion rate of EG is 100%
And the GLO yield was 89%. The results are summarized in Table 3. The production of glycolaldehyde, a reaction intermediate (by-product), was slightly observed. The amount of methanol lost by the side reaction such as combustion was 10% by weight of the supplied methanol.

Comparative Example 1 The first-stage reaction was carried out using a comparative supply gas (a) containing no alcohol (a). That is, the composition of the supply gas (a) for comparison was EG 4.0% by volume,
The pre-stage reaction was carried out under the same conditions as in Example 1 except that 4.8% by volume of oxygen, 0% by volume of methanol and 0% by volume of water (nitrogen gas balance) were used. The temperature of the catalyst layer is 5
86 ° C was reached. The main reaction conditions are summarized in Table 1. As a result, the conversion of EG was 100%, but the yield of GLO was as low as 77%. The results are summarized in Table 3.

[Comparative Example 2] The first-stage reaction was carried out using a supply gas (a) for comparison containing water instead of the alcohol (a). That is, the composition of the supply gas (a) for comparison was changed to EG 4.0.
Volume%, oxygen 4.8 volume%, methanol 0 volume%, and water 3.0 volume% (nitrogen gas balance),
The first-stage reaction was carried out under the same conditions as in Example 1. The temperature of the catalyst layer reached 583 ° C. The main reaction conditions are summarized in Table 1. As a result, the conversion of EG was 100%, but the yield of GLO was as low as 79%. The results are summarized in Table 3.

Example 3 The composition of the supply gas (a) was changed to EG
4.0 vol%, oxygen 4.8 vol%, methanol 20.0
% Of water and 3.0% by volume of water (nitrogen gas balance), except that triethyl phosphite was added to the supply gas (a) such that the ratio of phosphorus to EG was 80 ppm. The first-stage reaction was carried out under the same conditions as in Example 1. The temperature of the catalyst layer reached 569 ° C. The main reaction conditions are summarized in Table 1. As a result, the conversion rate of EG is 1
00% and the GLO yield was 89%. The results are summarized in Table 3.

Example 4 The composition of the supply gas (a) was changed to EG
The first-stage reaction was carried out under the same conditions as in Example 1 except that the volume was changed to 4.0% by volume, 4.8% by volume of oxygen, 3.0% by volume of methanol, and 1.0% by volume of water (nitrogen gas balance). Was done. The temperature of the catalyst layer reached 567 ° C. The main reaction conditions are summarized in Table 1. As a result, the conversion rate of EG is 10
0% and the GLO yield was 89%. The results are summarized in Table 3.

Example 5 The composition of the supply gas (a) was changed to EG
The first-stage reaction was carried out under the same conditions as in Example 1 except that the volume was changed to 4.0% by volume, 4.8% by volume of oxygen, 1.0% by volume of methanol, and 0% by volume of water (nitrogen gas balance). Was. The temperature of the catalyst layer reached 583 ° C. The main reaction conditions are summarized in Table 1. As a result, the conversion rate of EG is 100%
And the yield of GLO was 82%. The results are summarized in Table 3. The concentration of the obtained GLO aqueous solution is about 58
% Of a commercially available GLO aqueous solution (concentration 40
% By weight). That is, a GLO aqueous solution having a higher concentration than that of a commercially available product could be stably obtained.

Example 6 The composition of the supply gas (a) was changed to EG
The first-stage reaction was carried out under the same conditions as in Example 1 except that the volume was changed to 4.0% by volume, 4.0% by volume of oxygen, 4.0% by volume of methanol, and 0% by volume of water (nitrogen gas balance). Was. The temperature of the catalyst layer reached 573 ° C. The main reaction conditions are summarized in Table 1. As a result, the conversion of EG was 99%, and the yield of GLO was 85%. The results are summarized in Table 3.

Example 7 The composition of the supply gas (a) was changed to EG
The first-stage reaction was carried out under the same conditions as in Example 1 except that the volume was changed to 4.0% by volume, 6.0% by volume of oxygen, 4.0% by volume of methanol, and 0% by volume of water (nitrogen gas balance). Was. The temperature of the catalyst layer reached 572 ° C. The main reaction conditions are summarized in Table 1. As a result, the conversion rate of EG is 100%
And the GLO yield was 89%. The results are summarized in Table 3.

Example 8 The composition of the supply gas (a) was changed to EG
The first-stage reaction was performed under the same conditions as in Example 1 except that the volume was changed to 3.0% by volume, 4.0% by volume of oxygen, 3.0% by volume of methanol, and 0% by volume of water (nitrogen gas balance). Was. The temperature of the catalyst layer reached 557 ° C. The main reaction conditions are summarized in Table 2. As a result, the conversion of EG was 99%, and the yield of GLO was 86%. The results are summarized in Table 3.

Embodiment 9 The composition of the supply gas (a) was changed to EG
The first-stage reaction was carried out under the same conditions as in Example 1 except that the volume was changed to 5.0% by volume, 6.0% by volume of oxygen, 4.0% by volume of methanol, and 0% by volume of water (nitrogen gas balance). Was. The temperature of the catalyst layer reached 588 ° C. The main reaction conditions are summarized in Table 2. As a result, the conversion rate of EG is 100%
And the yield of GLO was 84%. The results are summarized in Table 3.

Example 10 The composition of the supply gas (a) was changed to EG
The first-stage reaction was performed under the same conditions as in Example 1 except that the volume was changed to 5.0% by volume, 6.0% by volume of oxygen, 4.0% by volume of methanol, and 1.0% by volume of water (nitrogen gas balance). Was done. The temperature of the catalyst layer reached 587 ° C. The main reaction conditions are summarized in Table 2. As a result, the conversion rate of EG is 10
0% and the GLO yield was 84%. The results are summarized in Table 3.

Example 11 A pre-stage reaction was carried out in the same manner as in Example 1 to obtain GLO from EG. However, the catalyst
As (a), a gas inlet side in a reaction tube is filled with 10 g of metallic silver (electrolytic silver manufactured by Yokohama Metals Co., Ltd.) having a particle size of 20 to 30 mesh, and a particle diameter is placed on a gas outlet side in the reaction tube. Was filled (laminated) with 10 g of metallic silver of 16 mesh to 20 mesh (same as above).

Then, the composition of the supply gas (a) was changed to EG 4.0
Volume%, oxygen 4.8 volume%, methanol 4.0 volume%,
The first-stage reaction was carried out under the same conditions as in Example 1 except that the water content was changed to 0% by volume (nitrogen gas balance). The temperature of the catalyst layer reached 555 ° C. Table 2 shows the main reaction conditions.
Summarized in As a result, the conversion of EG was 100%, and the yield of GLO was 91%. The results are summarized in Table 3. The concentration of the obtained GLO aqueous solution was about 56% by weight, which was higher than that of a commercially available GLO aqueous solution (concentration: 40% by weight). That is, a GLO aqueous solution having a higher concentration than that of a commercially available product could be stably obtained.

Example 12 The same conditions as in Example 11 were adopted except that the supply gas (a) was continuously supplied to the reaction tube at a space velocity (SV) of 100,000 hr ^-1. The first-stage reaction was performed. The temperature of the catalyst layer reached 554 ° C. The main reaction conditions are summarized in Table 2. As a result, E
The conversion of G was 100% and the yield of GLO was 90%. The results are summarized in Table 3.

Example 13 The amount of metallic silver charged on the gas outlet side in the reaction tube was changed to 5 g.
When the space velocity (SV) of the supplied gas (a) is 70,000 hr ^-1
The first-stage reaction was carried out under the same conditions as in Example 11, except that the solution was continuously supplied to the reaction tube in such a manner that The temperature of the catalyst layer reached 555 ° C. The main reaction conditions are summarized in Table 2. As a result, the conversion rate of EG was 99% and GL
The yield of O was 90%. The results are summarized in Table 3.
The production of glycolaldehyde, a reaction intermediate (by-product), was slightly observed. The amount of methanol lost by the side reaction such as combustion was 13% by weight of the supplied methanol.

Example 14 The amount of metallic silver charged on the gas outlet side in the reaction tube was changed to 5 g, and the supply gas was changed.
The composition of (a) was changed to 4.0% by volume of EG, 4.8% by volume of oxygen, 20.0% by volume of methanol, and 0% by volume of water (nitrogen gas balance), and EG was added to the supply gas (a).
The first-stage reaction was carried out under the same conditions as in Example 11 except that triethyl phosphite was added such that the ratio of phosphorus to the mixture became 100 ppm. The temperature of the catalyst layer is 558 ° C.
Reached. The main reaction conditions are summarized in Table 2. as a result,
EG conversion is 100% and GLO yield is 91%
Met. The results are summarized in Table 3.

Example 15 First, as catalyst (a),
Metallic silver modified with a phosphorus-containing compound was prepared by the following method. That is, an 85% by weight aqueous solution of phosphoric acid was added to metallic silver having a particle diameter of 20 to 30 mesh (electrolytic silver manufactured by Yokohama Metal Co., Ltd.), and the ratio of phosphorus to silver was 20%.
It was added so as to be 0 ppm, and phosphorus was supported on metallic silver. Then, the support was dried at 120 ° C. in air, and then calcined in air at 600 ° C. for 3 hours. In this way, metallic silver modified with phosphoric acid (phosphorus-containing compound) as catalyst (a) was prepared.

Using the obtained metallic silver as the catalyst (a), a pre-stage reaction was carried out in the same manner as in Example 1 to obtain GLO from EG. That is, the amount of the metallic silver charged in the reaction tube was changed to 5 g, and the composition of the supply gas (a) was changed to 4.0% by volume of EG, 4.8% by volume of oxygen, 4.0% by volume of methanol, and 1% by volume of water. 0.0% by volume (nitrogen gas balance) and the supply of the phosphorus-containing compound (a)
Except that it is not supplied together with
The first-stage reaction was performed. The temperature of the catalyst layer reached 590 ° C. The main reaction conditions are summarized in Table 2. As a result, the conversion of EG was 100%, and the yield of GLO was 79%. The results are summarized in Table 3.

Example 16 The same operation as in Example 15 was carried out except that a 85% by weight aqueous solution of phosphoric acid was added to metallic silver so that the ratio of phosphorus to silver was 80 ppm. A modified metallic silver was prepared.

Using the obtained metallic silver as the catalyst (a), a pre-stage reaction was carried out in the same manner as in Example 1 to obtain GLO from EG. That is, the amount of the metallic silver charged in the reaction tube was changed to 5 g, and the composition of the supply gas (a) was changed to 4.0% by volume of EG, 4.8% by volume of oxygen, 4.0% by volume of methanol, and 1% by volume of water. 0.0% by volume (nitrogen gas balance), under the same conditions as in Example 1,
The first-stage reaction was performed. The temperature of the catalyst layer reached 578 ° C. The main reaction conditions are summarized in Table 2. As a result, the conversion of EG was 100%, and the yield of GLO was 82%. The results are summarized in Table 3.

[0088]

[Table 1]

[0089]

[Table 2]

[0090]

[Table 3]

[Example 17] GLO
From MGO. Further, titania-added ferric phosphate as a catalyst (b) was prepared by the following method.

First, ferric phosphate (FePO ₄ .4H ₂ O; a reagent manufactured by Katayama Chemical Industry Co., Ltd.) as a metal phosphate and anatase type titanium dioxide (TiO ₂ ; And a reagent (manufactured by Wako Pure Chemical Industries, Ltd.) using a mortar, and the mixture was conditioned with water. The molar ratio of iron to phosphorus in the ferric phosphate is 1/1. The amount of titanium dioxide added is
It was set so that the ratio of titania in the obtained titania-added ferric phosphate was 30% by weight.

Next, the obtained mixture was molded using a so-called tableting plate, and dried in air at 120 ° C.
Then, the obtained cylindrical pellet having an outer diameter of 5 mm and a length of 6 mm was fired in air at 500 ° C. for 3 hours. Thus, titania-added ferric phosphate as the catalyst (b) was prepared. Then, a predetermined amount of the titania-added ferric phosphate was charged into the latter-stage reactor.

As the reaction conditions for the first-stage reaction, the reaction conditions described in the above Example 2 were employed. Methanol was used as the alcohol (b). Then, the proportions of GLO, oxygen, and methanol in the supply gas (b) formed in the vaporization chamber connected to the downstream reactor were 3.0% by volume, 4.0% by volume, and 15.0% in that order. % By volume (nitrogen gas balance). Oxygen and methanol are determined by quantifying the amount of oxygen and methanol contained in the reaction gas obtained in the first-stage reaction, and deficient in the second-stage gas supply port so that the supply gas (b) having the above composition can be formed. And supplied to the vaporization chamber.

Then, the supply gas (b) having the above composition was continuously supplied to the subsequent reactor at a space velocity (SV) of 1,300 hr ^-1 to perform the latter reaction. The reaction temperature was 250 ° C.

The components of the obtained reaction gas were analyzed by the above method. As a result, the conversion of GLO was 100% and M
The selectivity of GO is 78% and MGO based on EG
Was 69%. Table 4 summarizes the main reaction conditions and results.

[Example 18] A second-stage reaction was carried out under the same conditions as in Example 17 except that the reaction conditions shown in the above-mentioned Example 11 were employed as the reaction conditions for the first-stage reaction. That is,
The molar ratio of oxygen and methanol to GLO produced by the first-stage reaction was determined from the molar ratio obtained in Example 17 (oxygen / GLO = 1.3, methanol / GL).
(O = 5.0), a subsequent reaction was performed. As a result, the conversion of GLO was 100%, the selectivity of MGO was 78%, and the yield of MGO based on EG was 71%.
%Met. Table 4 summarizes the main reaction conditions and results.

Example 19 An alcohol (a) and an alcohol (b) were made to be the same compound, and a first-stage reaction and a second-stage reaction were continuously performed, and a product was separated from a reaction gas obtained in the second-stage reaction. (Hereinafter, referred to as recycle gas) was reused as a part of the feed gas (a) for the first-stage reaction, whereby MGO was obtained from EG via GLO.
FIG. 1 shows a block diagram for explaining the outline of the apparatus and operation relating to the reaction in this example.

That is, a SUS pipe having an inner diameter of 1 inch was used as a reaction tube for the pre-stage reaction (pre-stage reactor), and metallic silver (Yokohama Metal Co., Ltd .; 88 g of electrolytic silver (mesh to 30 mesh) was charged. Further, a preheater for heating the supply gas (a) supplied to the reaction tube to a predetermined temperature was attached to the gas inlet side of the reaction tube. The preheater has an EG supplied to the preheater.
An evaporator was installed to evaporate. Further, a heat insulating material was wound around the outside of the reaction tube to keep the temperature of the reaction tube constant, so that the temperature (reaction temperature) of the catalyst layer during the first-stage reaction was maintained at a predetermined temperature. That is, the inside of the reaction tube was kept warm so that the first-stage reaction proceeded under conditions almost equal to the adiabatic reaction.

The supply gas (a) is a mixture of recycle gas (including methanol), vaporized EG and air. As the reaction conditions for the first-stage reaction, the reaction conditions described in Example 4 above were employed. Therefore, EG in the supply gas (a),
The proportions of oxygen, methanol as alcohol (a), and water were 4.0 vol%, 4.8 vol%, 3.0
% And 1.0% by volume (nitrogen gas balance). That is, as for the air, oxygen, methanol and the like contained in the recycle gas were quantified, and the shortage thereof was appropriately supplied so that the supply gas (a) having the above composition could be constantly formed. In addition, triethyl phosphite is added to the EG supplied to the evaporator, and the ratio of phosphorus to the EG is 60%.
ppm was added in advance.

On the other hand, a predetermined amount of titania-added ferric phosphate as the catalyst (b) prepared in Example 17 was charged into the latter reactor. Further, a condenser for condensing the reaction gas was attached to the gas outlet side of the latter reactor, and a product such as MGO was separated from the reaction gas as a condensate. The temperature of the recycle gas at the outlet of the condenser was set to 15 ° C. A part of the recycle gas was purged, and the rest was continuously supplied to the reaction tube for the first-stage reaction. still,
The concentration of unreacted methanol contained in the recycled gas was adjusted by controlling the temperature of the refrigerant used in the condenser.

As the alcohol (b), methanol was used. Then, the proportions of GLO, oxygen and methanol in the supply gas (b) were changed to 2.8% by volume, 3.7
% And 14.0% by volume (nitrogen gas balance). Oxygen (air) and methanol are used to determine the amount of oxygen and methanol contained in the reaction gas obtained in the preceding reaction and to vaporize the shortage so that the supply gas (b) having the above composition can be formed. Supplied to the room. The vaporization chamber is used to vaporize methanol and form the mixed gas of the reaction gas obtained in the previous reaction, the vaporized methanol and air, and continuously supply the mixed gas to the subsequent reactor. Attached to the gas inlet side of the reactor.

Then, the supply gas (a) having the above composition is continuously supplied to the reaction tube so that the space velocity (SV) becomes 45,000 hr ^-1, and a pre-stage reaction is carried out. The gas (b) was continuously supplied to the subsequent reactor at a space velocity of 1,300 hr ^-1 to perform the latter reaction. The reaction temperature of the latter reaction was 250 ° C.

As a result of analyzing the components of the reaction gas obtained in the first-stage reaction by the above method, the conversion of EG was 100%,
The GLO yield was 88%. On the other hand, the components of the reaction gas obtained in the second-stage reaction were analyzed by the above method. as a result,
The conversion of GLO is 100% and the selectivity of MGO is 7
The yield of MGO based on EG was 69%. Table 4 summarizes the main reaction conditions and results.

[Example 20] A second-stage reaction was carried out under the same conditions as in Example 19, except that the reaction conditions shown in the above-mentioned Example 5 were employed as the reaction conditions for the first-stage reaction. That is, the first-stage reaction and the second-stage reaction were continuously performed.

The proportions of EG, oxygen, methanol, and water in the supply gas (a) were set to 4.0% by volume and 4.
8% by volume, 1.0% by volume and 0% by volume (nitrogen gas balance). GLO, oxygen, in feed gas (b)
And the proportion of methanol in this order 2.6 vol%,
It was set to 3.6% by volume and 13.0% by volume (nitrogen gas balance). The temperature of the recycle gas in the second-stage reaction was set to 0 ° C. in order to adjust the concentration of unreacted methanol contained in the recycle gas to the above-mentioned amount.

As a result of analyzing the components of the reaction gas obtained in the first-stage reaction by the method described above, the conversion of EG was 100%.
The GLO yield was 82%. On the other hand, the components of the reaction gas obtained in the second-stage reaction were analyzed by the above method. as a result,
The conversion of GLO is 100% and the selectivity of MGO is 7
The yield of MGO based on EG was 64%. Table 4 summarizes the main reaction conditions and results.

Comparative Example 3 A second-stage reaction was performed under the same conditions as in Example 19, except that the reaction conditions for the first-stage reaction were the same as those described in the first comparative example. That is, the first-stage reaction and the second-stage reaction were continuously performed. However, no recycled gas was used.

The proportions of EG, oxygen, methanol, and water in the supply gas (a) for comparison were 4.0% by volume, 4.8% by volume, 0% by volume, and 0% by volume (nitrogen gas balance, respectively). ). GLO in supply gas (b),
The ratios of oxygen and methanol were 2.2% by volume, 3.0% by volume, and 11.0% by volume (nitrogen gas balance) in this order.

As a result of analyzing the components of the reaction gas obtained in the first-stage reaction by the above-mentioned method, the conversion of EG was 100%.
The GLO yield was 76%. On the other hand, the components of the reaction gas obtained in the second-stage reaction were analyzed by the above method. as a result,
The conversion of GLO is 100% and the selectivity of MGO is 7
However, the yield of MGO based on EG was 59%.
% Was low. Table 4 summarizes the main reaction conditions and results.

[0111]

[Table 4]

[0112]

According to the method for producing α-oxoaldehyde according to claim 1 of the present invention, α-oxoaldehyde can be produced in a higher yield than before. In addition, in the conventional method, for example, a large amount of water must be supplied (entrained supply) to the reaction system in order to obtain α-oxoaldehyde. On the other hand, according to the above method, the alcohol (a) coexists. Since α-oxoaldehyde is stabilized, it is not necessary to supply, for example, water to obtain the α-oxoaldehyde. Therefore, according to the above method, α-
Oxaldehyde can be produced at a higher yield than before, and an α-oxoaldehyde solution or gas having a higher concentration than before can be stably obtained.

According to the method for producing α-oxoaldehyde according to the second aspect of the present invention, there is an effect that α-oxoaldehyde can be produced in a higher yield.

According to the method for producing an α-oxocarboxylic acid ester according to claim 3 of the present invention, the disadvantages of the conventional method, for example, the presence of water in the reaction system,
Since an inconvenience such as hydrolysis of the oxocarboxylic acid ester can be avoided, an effect is obtained that the α-oxocarboxylic acid ester can be produced in a higher yield than before.

According to the method for producing an α-oxocarboxylic acid ester according to claim 4 of the present invention, there is no need to remove the alcohol (a) from the α-oxoaldehyde prior to producing the α-oxocarboxylic acid ester. . Therefore, there is an effect that the α-oxocarboxylic acid ester can be produced more easily.

According to the method for producing an α-oxocarboxylic acid ester according to claim 5 of the present invention, a reaction gas obtained by vapor-phase oxidation of α-oxoaldehyde and an alcohol (b), or a reaction gas obtained from the reaction gas The gas after separating products such as α-oxocarboxylic acid ester or the gas containing uncollected alcohol after separating and collecting alcohol from the gas is subjected to the gas-phase oxidation of alkylene glycol. Gas to be supplied (alkylene glycol and alcohol (a)
) Can be reused as at least a part, more preferably all, of the gas containing In this case, the alcohol (a) to be recycled contains the unreacted alcohol (b), so that the alcohol (a) and the alcohol (b) are the same compound, and When it is carried out, there is an effect that the α-oxocarboxylic acid ester can be more easily and efficiently produced from the alkylene glycol.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an outline of an apparatus and an operation related to a reaction in Example 19.

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI C07C 69/716 C07C 69/716 Z // C07B 61/00 300 C07B 61/00 300 (72) Inventor Kimio Ariyoshi Suita-shi, Osaka No. 5-8, Nishiomiboricho Nippon Shokubai Co., Ltd. (56) References JP-A-58-124730 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C07C 45/37

Claims (7)

(57) [Claims] 1. An alkylene glycol, comprising oxygen and a catalyst.
During the gas phase oxidation in the presence of (a), the alkylene glycol
A process for producing α-oxo aldehyde, comprising coexisting an alcohol (a) excluding phenol . 2. The method according to claim 1, wherein the molar ratio between the alkylene glycol and the alcohol (a) is in the range of 1/100 to 5/1. 3. The catalyst (a) is a metal catalyst and / or an oxide.
The α according to claim 1 or 2, wherein the α is a catalyst.
-A method for producing oxoaldehyde. 4. An alkylene glycol, comprising oxygen and a catalyst.
During the gas phase oxidation in the presence of (a), the alkylene glycol
To obtain α-oxoaldehyde in the coexistence of alcohol (a) except for the α-oxoaldehyde,
A process for producing an α-oxocarboxylic acid ester, comprising subjecting (b) or an olefin to gas phase oxidation in the presence of oxygen and a catalyst (b). 5. The method according to claim 1, wherein the alcohol (a) and the alcohol (b) are
The α- according to claim 4, which is the same compound.
A method for producing an oxocarboxylic acid ester. 6. The method according to claim 6, wherein the alcohol (a) is α-oxoalde
Reaction gas obtained by gas-phase oxidation of hydr and alcohol (b)
It contains unreacted alcohol (b) contained in
The α-oxocarboxylic acid according to claim 4 or 5, wherein
The method of manufacturing steal. 7. The catalyst (a) is a metal catalyst and / or an oxide.
A catalyst, wherein the catalyst (b) comprises a phosphorus-containing inorganic oxide
7. The α according to claim 4, 5 or 6, wherein
-A method for producing an oxocarboxylic acid ester.