JP2001321669A - Manufacturing method of glyoxal and catalyst therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a novel manufacturing method of glyoxal, which has high conversion rate, selectivity and space time yield and is capable of reducing impurities, and to produce a novel catalyst used for the method. SOLUTION: Ethylene glycol and molecular state oxygen are passed through a multilayer catalyst layer composed of at least one layer of a silver catalyst, at least one layer of a silver based catalyst consisting of silver and palladium and at least one layer of a copper catalyst in the order of the copper catalyst layer, the silver based catalyst layer and the silver catalyst layer at 400-700 deg.C to perform oxidative dehydrogenation reaction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing glyoxal. More specifically, the present invention relates to a method for producing glyoxal by a gas phase oxidative dehydrogenation reaction of ethylene glycol and a catalyst for the same.

[0002]

BACKGROUND OF THE INVENTION Ethylene glycol is oxidatively dehydrogenated,
There are various proposals for a method for producing glyoxal, a compound very useful as a fiber processing agent, a paper processing agent, a soil hardening agent, and other organic intermediates. For example,
A method using a catalyst comprising Cu and / or Ag and phosphorus (Japanese Patent Publication No. 48-1364), a method of using a catalyst having a certain particle size (0.1 to
Oxidation method in the presence of 2.5 mm) silver crystals (Japanese Patent Publication No. 61-54011), and a method of catalytic oxidation with silver crystals in the presence of a vaporized phosphorus compound (Japanese Patent Publication No. 2-4929).
No. 2) has also been proposed. A method for producing dialdehyde using a silver catalyst supported on a carrier has also been proposed. For example, Izv.Akad.Nauk.SSSR, Ser.Khim.641-643 (1
964), the reaction was carried out at a reaction temperature of 600 ° C. with an alumina-supported silver catalyst (Ag supported amount 32%).
Only a low space-time yield of 23.8 kg-GX / m ³ -cat · Hr was obtained.

Further, there is a method described in JP-B-63-4816 and the like, but it has disadvantages such as using diluted ethylene glycol and a large amount of unreacted ethylene glycol. Japanese Patent Publication No. 53-10570 discloses a method using a catalyst composed of silver oxide and zinc oxide. A method for producing dialdehyde by oxidative dehydrogenation of ethylene glycol in the presence of a copper catalyst or a silver catalyst is known. On the other hand, when glyoxal is used as a fiber aid or a papermaking aid, problems such as yellowing occur when impurities such as glycolaldehyde are large, which is not preferable. Further, even when glyoxal is used as an intermediate material for dyes, medicines, fragrances, etc., it is necessary to reduce the amount of impurities such as glycolaldehyde since these reactions are not preferred if such impurities are excessive.

Since it is difficult to separate and remove unreacted ethylene glycol and glycolaldehyde as a reaction intermediate in a glyoxal aqueous solution as a product, the raw material ethylene glycol does not remain in the oxidative dehydrogenation step, or It is necessary to prevent the formation of the intermediate glycolaldehyde. Therefore, strict production conditions, appropriate catalyst must be selected,
Therefore, conventionally, impurities have been reduced at the expense of yield. Also, silver particles used for the catalyst are expensive,
Silver is recovered from the used catalyst and reused. For example, a used catalyst is dissolved in nitric acid, concentrated, recovered as silver nitrate crystals by recrystallization, and a silver nitrate solution is electrolyzed to regenerate silver. A method of electrolysis in an electrolytic solution to precipitate silver particles is known, and is used industrially as a catalyst.

However, when such a silver catalyst is used for a long period of time and solidified or agglomerated is regenerated many times, unreacted raw materials and impurities of reaction intermediates increase, which is a serious problem in the preparation of the silver catalyst. Met. Furthermore, in the preparation of a supported catalyst, if the preparation lot is different or the preparation scale is different, even if the raw materials are reacted under similar conditions, the preparation of a catalyst with good reproducibility such as an increase in the amount of glycolaldehyde as an impurity will occur. It was difficult. Japanese Patent Application Laid-Open No. 58-59933 discloses a method of catalytically oxidizing with a silver catalyst to which phosphorus has been added in the presence of a phosphorus compound which vaporizes ethylene glycol. Is reacted with ethylene glycol to which primary ammonium phosphate has been added to maintain a glyoxal yield of 80% for 11 days, but still has a drawback that the space-time yield is low.

The method described in JP-B-61-54011 has a high glyoxal yield (55-66.4%),
High space-time yield (9.4-14.6 g-glyoxal / c
m ³ -cat · hr). However, since unreacted ethylene glycol, which has a low conversion rate (97.8 to 98%) and is difficult to separate from glyoxal, remains and is mixed with the desired glyoxal, it is a method for industrially producing a high-quality product. Is not a satisfactory way. U
SP4,555,583 (corresponding to Japanese Patent Publication No. 2-49292) discloses a method in which ethylene glycol is catalytically oxidized with silver crystals in the presence of a vaporized phosphorus compound. The reaction was carried out at a temperature of 501 ° C, ethylene glycol conversion 100%, glyoxal selectivity 80.4%, glycol aldehyde selectivity 1.
It has achieved 3%. However, this method also has a drawback that although the yield of glyoxal is high, there is too much glycolaldehyde as an impurity. The amount of glycolaldehyde produced can be reduced by using fine silver particles as a catalyst (Example 1), but is not preferred because the pressure loss of the catalyst layer increases.

JP-A-63-156939 and JP-A-63-258829 disclose glyoxal production examples, and in the glyoxal production example of JP-A-63-156939, the glyoxal yield (77.1) is disclosed.
%) Is high, but the raw material conversion (94.2%) and the product space-time yield (0.092 g-glyoxal / cm ³ -cat · hr)
The glyoxal yield (71.5%) is high in the glyoxal production example of JP-A-63-258829, but the raw material conversion (99%) and the product space-time yield (0.08
2 g-glyoxal / cm ³ -cat · hr) is low. Also, various methods for producing dialdehyde using a silver catalyst supported on a carrier have been proposed, and the amount of silver supported on such a catalyst is as low as 5 to 30% by weight. For example, Izv. Aka
d. In Nauk. SSSR, Ser. Khim. 641 to 643 (1964), the reaction is carried out at a reaction temperature of 600 ° C. using a silver catalyst supported on alumina (32% by weight of Ag supported).
The space-time yield was 23.8 kg-glyoxal / m ³ -cat · hr, and only low results were obtained. Tokiko 63-48
In Example 2 of No. 16, the reaction was carried out at a reaction temperature of 400 ° C. using a silver supported on alumina catalyst (Ag supported amount: 10% by weight) to obtain a conversion of 98%, a selectivity of 65%, and a space-time yield of 120 kg-
Although glyoxal / m ³ -cat · hr was obtained, the space-time yield was low and it was not a satisfactory method.

In Example 3 of JP-A-58-38227, silver conversion was carried out on a silicon catalyst containing 200 ppm of ammonium phosphate as phosphorus (Ag loading 8% by weight). % And selectivity of 74%, but the space-time yield is (0.26 kg-
Glyoxal / m ³ -cat · hr). JP-A-63-
In Example 3 of No. 156739, the reaction was carried out at a temperature of 360 ° C. using silver-coated steatite spheres as a catalyst, and the conversion was 9%.
2.1%, selectivity of 67%, 2.7% glycolaldehyde yield, space time yield 40kg- glyoxal / m ³ -cat
・ Hr grade is obtained. In this method, the yield is high, but there are many unreacted ethylene glycol and glycol aldehyde,
Further, there is a disadvantage that the space-time yield is low. Furthermore, Journa
l of Catalysis, 142, 729-734 (1993), 55% by silver catalyst supported on silicon carbide (5% by weight, 8% by weight of Ag).
The reaction was carried out at 0 ° C., and the conversion was 98.5%, the selectivity was 73%,
Although a space-time yield of 920 kg-glyoxal / m ³ -cat · hr has been obtained, there are many unreacted ethylene glycols, and the space-time yield is low. That is, in the method for producing glyoxal, a silver catalyst that specifically has high conversion, selectivity, and space-time yield and reduces impurities has not yet been developed.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to provide a novel method for producing glyoxal with high conversion, selectivity and space-time yield, and containing few impurities. or,
The present invention is to provide a new catalyst used in this method.

[0010]

Means for Solving the Problems The present inventors have conducted intensive studies on a method for producing glyoxal by vapor phase oxidation of ethylene glycol to overcome the drawbacks of the conventional method, and as a result, have completed the present invention. is there. That is, the method for producing glyoxal of the present invention comprises flowing ethylene glycol through at least one silver catalyst layer, at least one silver-based catalyst layer composed of silver and palladium, and at least one copper catalyst layer. And oxidatively dehydrogenate at 400 to 700 ° C.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The silver catalyst used in the present invention is silver crystal particles obtained by electrolysis of an aqueous silver nitrate solution, shavings of silver bullion, spray-quenched particles of molten metal, or supported silver. Also,
The silver-based catalyst used in the present invention is a catalyst containing silver as a main component and adding palladium to silver, or a catalyst obtained by adding silver to an inert carrier supporting silver. In this silver-based catalyst, silver crystal particles obtained by electrolysis of an aqueous silver nitrate solution, shavings of silver bullion, spray-quenched particles of molten metal, or supported silver can be used as silver. In these silver catalysts and silver-based catalysts, the carrier for supporting silver is not particularly limited as long as it is generally used as a carrier for the catalyst, but the carrier itself has almost no activity as a catalyst. Those having a relatively small specific surface area and a relatively small particle size are preferably used. Examples of the type of the carrier include oxides, nitrides, carbides, intermediate compositions thereof, and other inert inorganic compounds. Among them, for example, the specific surface area is 5 m ^2.
/ G or less, preferably 0.01 to 2.0 m ² / g, and a particle size of 25 to 1000 μm, more preferably 50 to 500 μm.
μm silica, alumina, zirconia, silicon nitride,
Silicon carbide can be used. These carriers are repeatedly impregnated with an aqueous silver compound solution, mixed, dried, calcined, pulverized, and classified, whereby a supported catalyst having a desired silver content can be prepared. The supported amount of silver is preferably 50 to 90 wt% based on the total amount of the supported silver and the inert carrier.

In the silver catalyst, palladium is added in an amount of 0.001 to 10% by weight, preferably 0.01 to 5% by weight, more preferably 0.0 to 5% by weight, based on silver.
1 to 2% by weight. As a method of adding palladium,
A method in which palladium is melted together with silver and the melt is solidified and processed into a wire or shavings, or a method in which the melt is spray-quenched and processed into granules. Furthermore, the silver catalyst may be impregnated, mixed, dried, calcined, pulverized, and classified with an aqueous solution of palladium, and added and supported. Palladium is preferably present in a form that partially covers silver. Alternatively, a silver catalyst such as electrolytic silver or supported silver can be suspended in an aqueous solution of palladium, made alkaline with ammonia or the like, and reduced by flowing a reducing agent such as formalin or hydrazine or a hydrogen gas to obtain a catalyst. More favorable results can be obtained by using the above-mentioned silver-based catalyst by subjecting it to a heat treatment at 200 to 700 ° C. in a reducing atmosphere or an inert gas atmosphere before using the oxidative dehydrogenation reaction. Further, as the copper catalyst used in the present invention, copper crystal particles obtained by electrolysis or the like can be used.

[0013] Multilayer catalysts useful in the process of the present invention include:
At least one, preferably one to four, more preferably two or three copper catalyst layers, at least one layer, preferably one
It comprises from 4 to 4, more preferably 2 or 3 silver-based catalyst layers composed of silver and palladium, and at least 1 layer, preferably 1 to 4 layers, more preferably 2 or 3 silver catalyst layers. One or more of these three catalyst layers are:
A catalyst composed of catalysts having different shapes and particle diameters. For example, the copper catalyst layer, the silver-based catalyst layer made of silver and palladium, and the silver catalyst layer have a particle size of 0.1 to 2.0 mm. 0.1-0.4mm, 0.4-0.75mm, 0.75
A layer of catalyst particles having different particle diameters, such as 1.0 to 2.0 mm and 1.0 to 2.0 mm, is formed in multiple layers to form each type of catalyst layer. The total thickness of the multilayer catalyst used in the present invention is 5 to 100 mm, preferably 20 to 40 mm.

In the multilayer catalyst, the weight of the three kinds of catalysts is 2% of the total weight of all the catalyst particles.
0 to 30 wt%, particularly 25 wt%, and the ratio of the silver-based catalyst composed of silver and palladium is 10 to 30 wt%, particularly 20 w
t%, and the proportion of silver catalyst is 40-70 wt%, especially 5
5 wt%. Further, the numbers of the three types of catalyst layers may be the same or different from each other. The number of copper catalyst layers may be greater, equal to, or less than the number of silver catalyst layers.

In the present invention, oxidation is carried out by flowing ethylene glycol through at least one silver catalyst layer, at least one silver catalyst layer composed of silver and palladium, and at least one copper catalyst layer. As a result, the amount of unreacted raw materials and the reaction intermediate, such as glycolaldehyde, is reduced compared to conventional catalysts comprising silver and palladium or silver and copper. Conversion and glyoxal selectivity can also be ensured.

The method of the present invention is an oxidative dehydrogenation reaction using molecular oxygen. Pure oxygen or air may be used as molecular oxygen, but the latter is preferably used economically. In order to obtain glyoxal with a high yield, ethylene glycol and molecular oxygen are diluted with an inert gas to cause a reaction. Inert gases such as nitrogen, helium,
A rare gas such as argon, carbon dioxide, water vapor, or the like is used. A low-temperature reaction tends to increase the amount of unreacted ethylene glycol, and a high-temperature reaction tends to increase the production of formalin, carbon monoxide, and carbon dioxide, so that the amount of glyoxal produced decreases. Therefore,
The preferred reaction temperature in the process of the present invention is 400-70.
0 ° C.

In the present invention, the oxidative dehydrogenation reaction is carried out in the presence of phosphorus or a phosphorus compound. Phosphorus or a phosphorus compound may be preliminarily mixed with a raw material in a predetermined amount before the reaction, or may be added to the reaction system alone or as a solution separately from the raw material. The amount of phosphorus or phosphorus compound added is usually 0.05 to
10 ppm is appropriate. Phosphorus compounds include mono,
Various organic phosphorus compounds such as primary or tertiary phosphines such as di- or trimethylphosphine, phosphites such as methyl phosphite and ethyl phosphite, dimethyl ester of methyl phosphonate and diethyl ester of ethyl phosphonate can be effectively used. Are listed. However, a phosphorus compound having a high boiling point causes a need to make the evaporator temperature particularly high, or the phosphorus compound stays in the evaporator and decomposes and accumulates to cause corrosion of equipment materials, thereby generating iron. It is not preferable because rust or the like may fly to the reaction layer and adversely affect the reaction. Accordingly, organic phosphorus compounds having a relatively low boiling point, such as methyl phosphite, ethyl phosphite, methyl phosphate, and ethyl phosphate are more preferably used. By adding these phosphorus compounds, compared to the case where they are not added,
Generation of oxidation products such as carbon monoxide and carbon dioxide and decomposition products such as formaldehyde is remarkably suppressed, and the yield of glyoxal as a target product is significantly improved.

[0018]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. Example 1 (Catalyst preparation) a. Of the silver particles obtained by the electrolysis method,
Silver particles of ~ 500 [mu] m. This catalyst was designated as catalyst A. b. Of the silver particles obtained by the electrolysis method,
50 g of silver particles having a particle size of
It was immersed in a nitric acid aqueous solution of dinitrodiammine palladium containing wt% palladium, and with stirring, 50 ml of 37% formalin was added, and further, ammonia water was added to adjust the pH to 10. After reduction with formalin at 50 ° C. for 2 hours, the mixture was filtered, washed with water and dried.
This catalyst was designated as catalyst B. c. Of the copper particles obtained by the electrolysis method, the particle size is 105
Copper particles that are ５００500 μm. This catalyst was designated as catalyst C. (Reaction) For each of the above catalysts, the lowermost layer of a stainless steel reactor having an inner diameter of 27.4 mm was charged with catalyst A at 55% by weight based on the total catalyst loading, and then catalyst B was placed on the catalyst layer. 20% by weight based on the total catalyst loading, and furthermore, as the uppermost layer, catalyst C was added at 25% by weight based on the total catalyst loading.
% By weight. Into the reactor filled in this way, 150 g of ethylene glycol obtained by adding 3 ppm of trimethyl phosphite as phosphorus to ethylene glycol was added.
hr, water 150 g / hr, air 280 l / h
r, and nitrogen at 650 l / hr were supplied in a downflow through an evaporator and a preheater. After the reaction was continued for 10 days, the reaction gas was cooled, and the product was separated and collected in an absorption tower using water as an absorbent. The reaction results are shown in Table 1.

Example 2 (Catalyst preparation) Among silver particles obtained by the electrolysis method, 50 g of silver particles having a particle size of 105 to 500 μm were mixed with an aqueous solution of dinitrodiammine palladium containing 1 wt% of palladium based on silver nitric acid. Then, while stirring, 50 ml of 37% formalin was added, and further, ammonia water was added to adjust the pH to 10. After reduction with formalin at 50 ° C. for 2 hours, the mixture was filtered, washed with water and dried. This catalyst was designated as catalyst D. (Reaction) With respect to the catalyst D and the catalysts A and B used in Example 1, the lowermost layer of the stainless steel reactor having an inner diameter of 27.4 mm was charged with the catalyst A at 55% of the total catalyst charge.
The catalyst layer was filled at 20% by weight with respect to the total catalyst loading, and the uppermost layer was loaded with Catalyst C at 25% by weight with respect to the total catalyst loading. 150 g / hr of ethylene glycol obtained by adding 3 ppm of trimethyl phosphite as phosphorus to ethylene glycol and 150 g of water were charged into the reactor filled in this way.
/ Hr, air 280 liters / hr and nitrogen 6
At a rate of 50 l / hr, it was fed in a downflow through an evaporator and a preheater. After the reaction was continued for 10 days, the reaction gas was cooled, and the product was separated and collected in an absorption tower using water as an absorbent. The reaction results are shown in Table 1.

Comparative Example 1 For catalysts A and B, the inner diameter was 27.4 as in Example 1.
The lower layer of the stainless steel reactor was loaded with catalyst A at 80% by weight based on the total catalyst loading, and then over the catalyst layer was loaded with catalyst B at 20% by weight based on the total catalyst loading. In the same manner as in Example 1, a reaction gas was passed to carry out a reaction.
The reaction results are shown in Table 1.

Comparative Example 2 For catalysts A and C, the inner diameter was 27.4 as in Example 1.
The lower layer of the stainless steel reactor was loaded with catalyst A at 75% by weight based on the total catalyst loading, and then over the catalyst layer was loaded with catalyst C at 25% by weight based on the total catalyst loading. In the same manner as in Example 1, a reaction gas was passed to carry out a reaction.
The reaction results are shown in Table 1.

Comparative Example 3 For catalysts A, B and C, the inner diameter was 2 as in Example 1.
The lower layer of the 7.4 mm stainless steel reactor was filled with catalyst A at 80% by weight based on the total catalyst loading, and then over the catalyst layer was placed catalyst B at 15% by weight based on the total catalyst loading.
The catalyst C was further filled as the uppermost layer at 5% by weight based on the total catalyst loading. In the same manner as in Example 1, a reaction gas was passed to carry out a reaction. The reaction results are shown in Table 1.

Comparative Example 4 The catalysts A, B and C had an inner diameter of 2 in the same manner as in Example 1.
The lower layer of the 7.4 mm stainless steel reactor was loaded with 25% by weight of catalyst C based on the total catalyst loading, and then over the catalyst layer was placed 20% by weight of catalyst B on the total catalyst loading.
The catalyst A was further filled as the uppermost layer in an amount of 55% by weight based on the total catalyst loading. In the same manner as in Example 1, a reaction gas was passed to carry out a reaction. The reaction results are shown in Table 1.

Comparative Example 5 As with Example 1, 100% by weight of Catalyst A was charged into a stainless steel reactor having an inner diameter of 27.4 mm as in Example 1. In the same manner as in Example 1, a reaction gas was passed to carry out a reaction. The reaction results are shown in Table 1.

[0025]

[Table 1] As is clear from Table 1, in Comparative Example 1, the reaction was performed with only the silver catalyst layer and the silver-based catalyst layer, in Comparative Example 2, the reaction was performed with only the silver catalyst layer and the copper catalyst layer, and in Comparative Example 5, the reaction was performed with only the silver catalyst layer. Was. In Comparative Example 3, the proportion of the copper catalyst layer was low. In Comparative Example 4, the order of stacking the catalyst layers is reversed. In either case, the yield is low,
Even though the yield is somewhat high, the proportion of by-products is high.

[0026]

According to the method and the catalyst of the present invention, in producing glyoxal from ethylene glycol,
The stability of the gas phase oxidation reaction is excellent, the raw material conversion rate is high, the space-time yield is high, the amount of by-products is small, and glyoxal can be produced in a high yield.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // C07B 61/00 300 C07B 61/00 300 (72) Inventor Koji Takamatsu 1-6 Takasago, Takaishi-shi, Osaka Address: Mitsui Chemicals, Inc. (72) Inventor, Hatsuo Inoue 1-6, Takasago, Takaishi, Osaka Prefecture Mitsui Chemicals, Inc. (72) Inventor: Takashi Okawa 1-6, Takasago, Takaishi, Osaka, Japan Mitsui Chemicals, Inc. F Term (reference) 4G069 AA08 BC31A BC31B BC32A BC32B BC72A BC72B CB07 CB19 DA06 EA07 4H006 AA02 AC45 BA05 BA25 BC10 BC32 BC34 BE30 4H039 CA62 CC20

Claims (5)

[Claims] At least one silver catalyst layer, at least one silver catalyst layer
A glyoxal production catalyst comprising a silver-based catalyst layer composed of silver and palladium and at least one copper catalyst layer which are sequentially formed in a multilayer structure. 2. At least one silver catalyst layer, at least one silver catalyst layer.
A silver catalyst layer comprising silver and palladium and a multilayer catalyst layer comprising at least one copper catalyst layer, wherein ethylene glycol and molecular oxygen are reacted at a reaction temperature of 400 to 700 ° C. with a copper catalyst layer, a silver catalyst layer, A method for producing glyoxal, characterized in that an oxidative dehydrogenation reaction is carried out by flowing the silver catalyst layer in this order. 3. The method according to claim 1, wherein the multilayer catalyst layer comprises 10 to 30% by weight of a copper catalyst.
10 to 30% by weight of a silver-based catalyst layer composed of silver and palladium,
3. The method for producing glyoxal according to claim 2, wherein the silver catalyst layer has a ratio of 40 to 80% by weight. 4. The method for producing glyoxal according to claim 2, wherein 0.05 to 10 ppm of phosphorus or a phosphorus compound is added to ethylene glycol and molecular oxygen as phosphorus relative to ethylene glycol, and the mixture is allowed to flow through the catalyst layer to carry out the reaction. 5. The method for producing glyoxal according to claim 2, wherein the silver-based catalyst comprising silver and palladium has a palladium content of 0.001 to 10% by weight based on silver.