JP2789123B2 - Method for producing glycolaldehyde - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing glycolaldehyde, and more particularly to a method for producing glycolaldehyde from ethylene glycol using a copper-zinc catalyst.

Glycol aldehydes are α-amino acids, pharmaceuticals, pesticides,
It is a useful compound as a raw material for photographic drugs or special polymers, and as a fiber treatment agent, odorant, and deodorant.

[Conventional technology]

The main known techniques for producing glycolaldehyde from ethylene glycol are as follows.

(1) A method in which ethylene glycol is brought into contact with a copper / chromium-based catalyst at 300 to 400 ° C. together with hydrogen and water vapor (US Pat. No. 168281, 1965). (2) Ethylene glycol is added to copper / zinc alloy (brass).
Method of contacting at 220-370 ° C under reduced pressure of ~ 45mmHg (Masato Nomura, Yoshito Fujiwara Research Report No.15, Kinki University Faculty of Engineering No.15) (3) Oxidative dehydrogenation of ethylene glycol using a silver, copper or gold metal catalyst Method for obtaining glycol aldehyde (DE3535483 A1) (4) Method of passing ethylene glycol and steam through a copper or copper / zinc catalyst (Japanese Patent Laid-Open No. 61-69740) (5) Silver, copper, silver oxide , Copper oxide etc. and silicon, phosphorus,
Or a method using a catalyst in combination with a boron compound (Japanese Patent Application Laid-Open No. 62-45548). Further, regarding activation of a copper-based catalyst, (6) hydrogenation of carbon monoxide in a copper / zinc two-component catalyst The tendency of deterioration in the activity of the methanol synthesis reaction is further suppressed by repetition of the hydrogenation reaction and air treatment (Koji Tsuchimoto, Yoshiro Morita, Journal of Engineering Chemistry, Vol. 70, No. 9 (1967)).

The method for producing each of the above glycol aldehydes is described in (4)
Except for the above method, the selectivity is poor and the production conditions are severe, making it difficult to say that it is an industrially sufficient technique.

The present inventors have proposed a method of passing a small amount of oxygen through a copper composite catalyst (Japanese Patent Application No. 63-329850) in addition to the above method (4) for the production of glycolaldehyde.
We have been developing a method to increase the selectivity of glycolaldehyde and extend the active life of the catalyst to more than 700 hours.

[Problems to be solved by the invention]

However, copper and zinc-based catalysts tend to have relatively low activity in the initial stage of the reaction, and there is still a point to be improved as an industrial production method of glycolaldehyde.

An object of the present invention is to provide a method for synthesizing glycol aldehyde from ethylene glycol, which has high selectivity for copper
It is an object of the present invention to improve the tendency that the activity at the initial stage of the reaction, which can be said to be a feature of the zinc-based catalyst, is relatively small, and to produce glycolaldehyde with high activity almost from the start of the reaction.

[Means for solving the problem]

The present inventors have conducted intensive studies to solve the above-mentioned problems of the prior art, and as a result, by performing a reaction treatment with ethylene glycol and an oxidation treatment with oxygen as a pretreatment of a copper or zinc-based catalyst, the catalyst activity was reduced for a short time. This makes it possible to produce glycolaldehyde with good activity from the beginning of the reaction.

That is, in the present invention, when producing a glycol aldehyde from ethylene glycol using a copper-zinc catalyst containing 0.3 to 3 parts by weight of zinc as zinc oxide with respect to 1 part by weight of copper oxide, A method of producing a glycol aldehyde, wherein a pretreatment of the catalyst is carried out by alternately repeating a reaction treatment with ethylene glycol and an oxidation treatment with oxygen before the catalyst.

The document (6) described in the above-mentioned prior art describes that the tendency of deterioration of activity is suppressed by repetition of reaction and air treatment. However, the reference (6) relates to a hydrogenation reaction, whereas the present invention relates to a dehydrogenation reaction, and there is an essential difference. In the literature (6), the initial activity of the air treatment reaction is as follows:
In the method of the present invention, the initial activity of the reaction itself after the oxygen treatment is increased by the repetition of the treatment, whereas the treatment is not changed by the repetition of the treatment.

That is, the present invention provides a pretreatment that repeats a reaction treatment with ethylene glycol and an oxidation treatment with air.
This is a new technology to increase glycolaldehyde synthesis activity in a short time.

[Specific description of the invention]

(1) Catalyst The copper / zinc composite catalyst that can be used in the present invention is a catalyst in which copper and zinc are chemically, that is, microscopically mixed, and copper is contained in 1 part by weight in terms of copper oxide. A catalyst containing 0.3 to 3 parts by weight of zinc as zinc oxide is used. As the catalyst, a catalyst obtained by adding a trace amount of another component to a two-component system of a copper component and a zinc component, a catalyst having these components supported on a carrier, or the like can be used. In this case, the addition of other components other than the copper component and the zinc component is intended for a composite effect or a carrier effect, and these other components may be added at the stage of preparing the copper component and the zinc component. These other components may be added at a later stage of the preparation. Examples of such other components include alkaline earth metals such as Cr, Mn, Pb, Ag and Mg, and alkali metals such as K. Examples of the carrier include alumina, pumice, diatomaceous earth, silica, asbestos, and thoria. The catalyst that can be used in the present invention is not limited to the catalyst described above.

The copper-zinc composite catalyst used in the present invention is in the form of powder,
Fibrous, thread-like, or a method of heating a Cu-Zn alloy such as a network in the presence of oxygen, a method of firing a mixture of a copper salt such as copper nitrate or copper acetate and a zinc salt such as zinc nitrate or zinc acetate, It can be produced by a method of calcining a coprecipitated salt obtained by adding an alkali to a copper and zinc nitrate solution. The calcination temperature of the copper / zinc-based catalyst at this time is 500 to 1200 ° C., and particularly when calcined at a high temperature, the glycolaldehyde selectivity in the reaction tends to be improved.

The catalyst may be subjected to hydrogen reduction at a temperature of about 150 to 350 ° C. before use. For example, in the case of a CuO.ZnO (1/1 molar ratio) catalyst, when the calcination temperature at the time of catalyst preparation is 500 to 800 ° C., hydrogen reduction can be usually performed at a temperature of about 150 to 350 ° C. before use. However, with a catalyst calcined at a high temperature of 800 to 1200 ° C., hydrogen reduction hardly proceeds at a temperature of about 300 ° C. In the case of the copper / zinc composite catalyst, the supply of ethylene glycol causes a certain amount of reduction to proceed promptly in the early stage of the reaction, and an active site appears. Therefore, the hydrogen reduction need not be performed.

(2) Pretreatment of Catalyst The pretreatment of the catalyst before the reaction in the present invention comprises repeating a reaction treatment with ethylene glycol and an oxidation treatment with oxygen.

Reaction Treatment In the reaction treatment with ethylene glycol, ethylene glycol is introduced into the catalyst layer at the reaction temperature to cause a reaction.

At this time, water and oxygen may be accompanied with ethylene glycol. This pre-treatment is a reduction treatment with ethylene glycol, which produces glycol aldehyde. Therefore, the presence of water and oxygen is preferable because side reactions at that time are suppressed.

Conditions for this pretreatment include a catalytic reaction type, a reaction temperature,
The amount of ethylene glycol or water to be introduced is arbitrary as long as ethylene glycol reacts to some extent, but it is preferable to employ the same conditions as those of the main reaction after the completion of the pretreatment because operation management is simple and convenient.

Under such conditions, the reaction temperature is usually 180-400
° C, preferably 200-350 ° C. The amount of water to be added is generally 0.1 to 100 mol, preferably 0.5 to 50 mol, particularly preferably 1 to 10 mol, per mol of ethylene glycol. When oxygen is introduced, it is usually preferable to introduce oxygen as cost. The amount of oxygen to be added is usually 0.3 or less per mole of ethylene glycol. If the amount of added oxygen is large, a large amount of glyoxal and carbon dioxide is by-produced, so that the amount is limited to a very small amount.

LHSV is usually 0.05 to 20, preferably 0.1 to 1 including water.
It is about 0.

The time of the reaction treatment with ethylene glycol as the pretreatment is 150 hours or less at a time, preferably 20 minutes to 5 hours.
Time. The optimum reaction time for one operation depends on the type of the copper-zinc catalyst. Generally, in order to sufficiently increase the yield of glycolaldehyde, it is necessary to increase the number of treatments as the loading rate is lower. Treatment for 150 hours or more is not preferable in terms of production time loss and raw material loss for the purpose of producing glycolaldehyde, and the effect of the pretreatment cannot be improved, and the effect may be weakened.

Oxidation treatment After the above-described ethylene glycol reaction treatment, oxygen is supplied to the heated catalyst portion to perform oxidation treatment. At the time of the oxidation treatment, it is preferable to remove ethylene glycol with a gas which does not affect the catalytic activity such as nitrogen and water vapor in advance.

Air is usually used as a source of oxygen,
At the same time, steam or an inert gas may be introduced. The oxidation treatment temperature is 100 to 400 ° C, preferably 150 to 300 ° C, and the amount introduced is adjusted so that the temperature rise due to heat generation during oxidation is kept at 20 ° C or less.

Normally, after the heat generation of the catalyst ends, the process is switched again to the above-described reaction treatment with ethylene glycol. However, complete termination of the oxidation is not necessarily required. There is a conversion effect. The time of the oxidation treatment depends on the amount of the catalyst.

The number of repetitions of the reaction treatment with ethylene glycol and the oxidation treatment with oxygen depends on the effect of improving the initial activity obtained, but is generally 20 times or less, preferably 2 to 10 times.

The ethylene glycol reaction as a pretreatment may be interrupted on the way. A gas that does not significantly change the state of the catalyst, such as an inert gas or water vapor, may be introduced between the interruption and the next oxidation treatment.

(3) The present reaction The present reaction after the above pretreatment is carried out in a reactor filled with a catalyst, ethylene glycol and water, and
By introducing a small amount of oxygen, glycolaldehyde can be stably produced for a long time.

The amount of water to be added is generally 0.1 to 100 mol, preferably 0.5 to 50 mol, particularly preferably 1 to 10 mol, per mol of ethylene glycol. When the amount of water is 0.1 mol or less, the selectivity of glycolaldehyde decreases, which is not preferable. If the amount of water exceeds 100 moles, the space-time yield is poor and the economic efficiency is reduced.

Oxygen is introduced as molecular oxygen, and is usually preferably introduced as air in terms of cost. The amount of oxygen added is usually 0.3 to 0.001 mol, preferably 0.2 to 0.005 mol, per 1 mol of ethylene glycol. If the amount of oxygen is less than 0.005 mol, the catalytic activity is greatly deteriorated, while if the amount of added oxygen is large, glyoxal and carbon dioxide gas are produced as by-products, and the selectivity of glycolaldehyde decreases.

The reaction temperature is usually 180 to 400 ° C, preferably 200 to 350 ° C,
Particularly preferably, it is 250 to 300 ° C. At a temperature of 180 ° C. or lower, the conversion of ethylene glycol is low, and at a temperature of over 400 ° C., the selectivity of glycol aldehyde decreases.

LHSV is usually about 0.05 to 20, preferably about 0.1 to 10.

The reaction pressure may be normal pressure, reduced pressure, or suppression. Normal pressure is preferably used because of the economical efficiency and easy operation of the reactor.

As the atmosphere gas, an inert gas such as nitrogen or argon may be added in addition to ethylene glycol, water vapor, and air.

〔Example〕

Hereinafter, the present invention will be described more specifically with reference to examples.

In the following experimental examples, analysis of products was performed by using gas chromatography and high performance liquid chromatography. The conversion of ethylene glycol and the selectivity of glycol aldehyde were calculated based on the following formula.

Example 1 A catalyst molded product having a composition of 50 parts by weight of CuO, 45 parts by weight of ZnO, and a specific surface area of 31 m ² / g (manufactured by Nikki Chemical Co., Ltd., N-211) was pulverized with a kneader, and a small amount of ion-exchanged water was added thereto to obtain a slurry. And α-alumina (Norton SA-5218, sphere diameter)
5mm) and slowly stirred to add N- 211 to α-alumina.
The powder was impregnated. After drying this impregnated body, in air, 10
And calcined for 4 hours at 00 ℃, CuO · ZuO-αAl 2 O 3 - catalyst (CuO / Z
nO weight ratio = 50/45, CuO.ZnO loading = 11%).

This catalyst was placed in a stainless steel reaction tube with an inner diameter of 15 mm.
After packing 49 ml in apparent volume and 56 g in weight, the following pre-reaction treatment was performed.

While maintaining the reaction tube at 260 ° C., a mixed solution of ethylene glycol: water = 1: 6 (molar ratio) was gasified through a preheater, passed through the reaction tube with LHSV 0.68, and simultaneously with 0.08 mole of ethylene glycol per mole. The reaction was carried out for 1 hour while passing air containing oxygen.

Next, after passing nitrogen gas through the reaction tube about 2 times quickly,
The oxidation treatment was performed by introducing air. This oxidation treatment
The air flow rate was adjusted while controlling the temperature rise due to the heat generation of the catalyst layer to 20 ° C. or less. The exotherm was over in one hour and the air treatment was over.

Next, the same treatment as the above-described reaction treatment with ethylene glycol was performed for 1 hour, and then the same oxidation treatment was performed for 1 hour.
Time, and again, the reaction-oxidation treatment is repeated,
Finished pre-processing.

While maintaining the temperature of the reaction tube after the pretreatment at 260 ° C., the same conditions as in the pretreatment, ie, ethylene glycol: water = 1: 6 (molar ratio), LHSV 0.68, oxygen with ethylene glycol molar ratio of 0.08, oxygen This reaction was carried out by introducing air containing.

Table 1 shows the conversion of ethylene glycol and the selectivity of glycol aldehyde during the pretreatment and in this reaction.

Example 2 In Example 1, the amount of N-211 catalyst powder was reduced to reduce CuO.
The same procedure as in Example 1 was performed, except that the ZnO loading rate was 8%, the number of repetitions of the pre-reaction treatment was 8, and the air treatment time per treatment was changed to 2 hours.

Table 2 shows the conversion of ethylene glycol and the selectivity of glycol aldehyde during the pretreatment and in this reaction.

Comparative Example 1 The same procedure as in Example 1 was carried out except that the pretreatment was not carried out.
This reaction was carried out in the same manner as described above.

The conversion of ethylene glycol and the selectivity of glycol aldehyde were as shown in Table 3.

Comparative Example 1 The same procedure as in Example 2 was carried out except that the pretreatment was not carried out.
This reaction was carried out in the same manner as described above.

The conversion of ethylene glycol and the selectivity of glycol aldehyde were as shown in Table 4.

[Effects of the Invention] In the method of the present invention, when producing glycolaldehyde from ethylene glycol using a copper-zinc catalyst, the pretreatment is repeated by repeating a reaction treatment with ethylene glycol and an oxidation treatment with oxygen, whereby the present reaction is carried out. Has a high activity from the beginning of the reaction, has a high selectivity for glycol aldehyde, and does not show a decrease in activity and selectivity due to the progress of the reaction.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) C07C 47/19 C07C 45/38 C07B 61/00 B01J 23/80 CA (STN)

Claims (1)

(57) [Claims] 1. A method for producing glycol aldehyde from ethylene glycol using a copper-zinc catalyst containing 0.3 to 3 parts by weight of zinc as zinc oxide with respect to 1 part by weight of copper oxide. A method for producing glycol aldehyde, wherein a pretreatment of a catalyst is performed by alternately repeating a reaction treatment with ethylene glycol and an oxidation treatment with oxygen before the catalyst.