JPS5859933A - Preparation of aldehyde or ketone - Google Patents

Abstract

PURPOSE:To prepare the titled compound useful as a raw material of textile processing and paper processing resin, synthetic intermediate of pesticides and pharmaceuticals, etc., in high yield, by the oxidative dehydrogenation of an alcohol in the presence of a P-containing silver catalyst capable of keeping its catalytic activity for a long period by the presence of P. CONSTITUTION:An aldehyde or ketone such as glyoxal, etc. is prepared by the oxidative dehydrogenation of an alcohol such as ethylene glycol, etc. with oxygen in the presence of a P-containing silver catalyst at 300-600 deg.C for 0.01-2sec under atmospheric pressure. The amount of oxygen is between the stoichiometric amount and 1.5 times thereof. The reaction is carried out either by feeding P or a P compound together with the raw materials to the catalyst bed, or interrupting the reaction at a stage when the catalytic activity is lowered, and feeding P or a P compound to the catalyst bed to reactivate the catalyst. The amount of P added to silver is <=500ppm and >=5-10ppm in terms of elementary P.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing aldehydes or ketones. More specifically, the present invention relates to a method for producing aldehydes or ketones by oxidative dehydrogenation of alcohols while maintaining the activity of a phosphorous-added silver catalyst for a long period of time.

The method of producing aldehyde-covered ketones by oxidative dehydrogenation of alcohol using a silver catalyst has been well known for a long time.
Formaldehyde is produced on a large scale from methanol in near constant yields.

However, when the alcohol used is a polyhydric alcohol such as ethylene glycol, propylene glycol, or butanediol, even if a normal cold catalyst is used, formaldehyde cannot be obtained in a high yield as when formaldehyde is obtained from methanol. is also known. Honkabuto Meisha is
As a result of intensive studies aimed at solving these problems, we found that a silver catalyst containing 500 ppm or less of phosphorus in terms of elemental phosphorus has a significant effect on the oxidative dehydrogenation of polyhydric alcohols. The present inventors have discovered that it is possible to maintain the catalytic activity for a long period of time by supplying a small amount of a phosphorus compound to the catalyst bed, and have completed the present invention.

That is, when producing an aldehyde or ketone by oxidative dehydrogenation of alcohol, the present invention uses a silver catalyst to which phosphorus is added, and supplies a trace amount of phosphorus or a phosphorus compound to the catalyst bed together with the reaction raw material. In the method of carrying out oxidative dehydrogenation or when the catalyst activity decreases, the supply of the reaction raw material is temporarily interrupted, and during that time, phosphorus reed or a phosphorus compound is supplied to the catalyst bed to reactivate the catalyst. This is a method to continue manufacturing by writing and supplying.

According to the method of the present invention, the reaction can be carried out for a long period of time while maintaining the activity of the catalyst by adding phosphorus or a phosphorus compound to the reaction system. Oxidative dehydrogenation can be carried out.

The phosphorus-added silver catalyst used in the method of the present invention has an ability to add phosphorus to silver of 500 p in terms of elemental phosphorus.
pm or less.

If the amount of phosphorus added exceeds 500 ppm, side reactions increase, which not only reduces the yield of the desired aldehyde but also gives unfavorable results such as the reaction product becoming yellow or yellowish brown. The lower limit of the amount of phosphorus added varies depending on the alcohol to be reacted, reaction conditions, etc., but is between 5 and 1.
One shift with 0 ppm or more is required.

The silver catalyst to which phosphorus has been added can be prepared by a conventional method, for example, by mixing silver with a predetermined amount of phosphorus, melting it in an inert atmosphere, forming an alloy, or by adding a phosphorus compound to a granular silver catalyst. It is prepared by immersing the entire body in a solution dissolved in an appropriate solvent, drying, and baking.

In the case of elemental phosphorus, for example, red phosphorus is dissolved in alcohol and immersed in a silver catalyst. This is then immersed in a silver catalyst. In the case of an organic compound such as triphenylphosphine, it is prepared by dissolving it in an organic solvent such as alcohol or acetone and immersing it in a silver catalyst, followed by drying and firing in the same manner. The phosphorus cabinet to be immersed is 500 p1) m for silver.
As mentioned above, the following should be maintained. The silver catalyst in which the solution containing phosphorus or a phosphorus compound is immersed may be a granular or wire-mesh catalyst made of pure silver, or a silver catalyst supported on a carrier such as alumina or silicon carbide.

In addition to the above-mentioned method of immersing an already prepared silver catalyst in a solution of phosphorus or a phosphorus compound, it is also possible to mix an aqueous solution of a phosphorus compound with an aqueous solution of a silver salt and support this on a carrier such as alumina or silicon carbide. The catalyst used in the method of the present invention can also be prepared by soaking, drying, and calcining.

As the silver salt, silver nitrate, silver acetate, etc. are often used, and as the phosphorus compound, ammonium phosphate, etc. are often used. silver salt and υ
In order to support the aqueous solution of the compound on the carrier, a conventional method such as dipping or spraying the solution onto the carrier is used.

Drying is carried out in air or nitrogen atmosphere at 50 to 150°C, and calcination is carried out at 350 to 600°C under air circulation for several hours. The carrier used usually has a surface area of 1 m'/gr or less.

Alcohols used in the method of the present invention include methanol,
Monohydric alcohols such as ethanol, ethylene glycol,
Glycols such as propylene glycol, 1,4-butanediol, and styrene glycol.

Examples of products obtained by oxidative dehydrogenation include glyoxal, methylglyoxal, 1°4-butanedial, and phenylglyoxal.

To carry out the process of the invention, the feed alcohol or alcohol and water (steam) are preheated and vaporized and fed to the catalyst bed. The supply ratio 1 of alcohol and steam in the case of coexistence of steam is expressed as a ratio of steam to liquid water, alcohol/water = 110.1 ~
1/1.0. In particular, the range of 110.5 to 1/2 is often used.

The amount of oxygen relative to the alcohol is preferably in the range of the stoichiometric amount to 1.5 times the stoichiometric amount required for alcoholic dehydrogenation to form an aldehyde or ketone. Air is usually used as the oxygen source.

The contact time of the reaction mixture to the catalyst bed is set to 0.01 to 2 seconds. The temperature of the catalyst bed in which the reaction is carried out is between 300 and 6
00°C, particularly preferably in the range of 350 to 550°C. Normal pressure is usually used as the reaction pressure. The products flowing out of the catalyst bed are collected by cooling and purified by a conventional method such as treatment with an ion exchange resin to form a product.

In the method of the present invention, phosphorus or a phosphorus compound is added to the reaction system in the process of producing aldehyde l or ketone as described above, so that the activity of the phosphorus-containing silver catalyst is sustained for a long time.

This method includes: ■ a method in which phosphorus or a phosphorus compound is supplied to the catalyst bed together with a raw material; and ■ a method in which the reaction is interrupted at the point where the activity of the catalyst has decreased, and phosphorus or a phosphorus compound is supplied to the catalyst bed to reactivate it. etc.

In the method of feeding phosphorus or a phosphorus compound to the catalyst bed together with the raw material, the amount of phosphorus compound fed to the catalyst bed is IX per hour per 1 kg of silver catalyst, converted to elemental phosphorus.
10' ~I X 10-2f/Hr/kgpat
.

A range of is preferred. The phosphorus compounds to be supplied include, for example, phosphoric acid, phosphorous acid, phosphates (ammonium phosphate, nium phosphate, etc.)
, phosphine, trialkylphosphine, or elemental phosphorus.

In the method of the present invention, alcohol or alcohol and steam are reacted together by being supplied to a catalyst bed together with air. Therefore, the phosphorus compound is dissolved in alcohol or water which is a raw material for steam, and the phosphorus compound is dissolved in a vaporizer together with a reaction raw material. A convenient method is to preheat and vaporize it before supplying it to the catalyst bed.

In a method in which the reaction is temporarily stopped and the phosphorus compound is supplied to the catalyst bed to reactivate the catalyst, the phosphorus compound as described above is dissolved in a solvent such as water, and this is preheated and vaporized. The supply business to the catalyst bed is lX.
It is carried out at a rate of 10'' to 6×10'f/Hr7k eat for several hours to 10 hours.

The temperature of the catalyst bed when feeding the phosphorus compound is usually 3
00 to 600°C, particularly preferably around 400°C.

The phosphorus compounds dissolved in water and the oxygen contained in the air are useful compounds for fiber processing, paper processing resin raw materials, agricultural and pharmaceutical synthesis intermediates, and the like.

The present invention will be explained below with reference to Examples.

Comparative Example A phosphorous-added silver catalyst was prepared by immersing a granular silver catalyst for formalin synthesis in an ammonium phosphate aqueous solution, drying it, and calcining it in air at 400°C. The amount of phosphorus added in terms of elemental phosphorus relative to silver is 200 ppm. This catalyst 10f' has an inner diameter of 12
m/m stainless steel tube and heated externally to 400°C in a sand fluidized bath. 50 of ethylene glycol
% aqueous solution was supplied to a preheater at I CC/Hr and vaporized.
Nitrogen was supplied to the catalyst bed at 100 mfl/min and air at 15 mQ/min. The reaction tube effluent was cooled and collected, and the amount of glyoxal produced was determined by high performance liquid chromatography. Table 1 shows the yield of glyoxal with respect to the operating time of the catalyst bed.

Example 1 Using the same catalyst as in the comparative example, 1100 pp of tertiary ammonium phosphate was added to a 50 wt % ethylene glycol aqueous solution as a feedstock and reacted. The reaction conditions are the same as in the comparative example. Table 1 shows the relationship between the operating time of the catalyst and the yield of glyoxal.

Table-1 Example-2 In Comparative Example-1, the catalyst bed was operated for 4 days, and when the activity decreased, the raw material supply was interrupted, and 5 m' of tertiary ammonium phosphate! −
An aqueous solution prepared by dissolving . After the supply of the ammonium phosphorus aqueous solution was completed, the supply of raw materials was restarted, and the yield of glyoxal was 80%. When the catalyst was treated with only water and air without ammonium phosphate, the yield of glyoxal was only 50%.

Patent applicant: Mitsui Toatsu Chemical Co., Ltd.

Claims (1)

[Claims] An aldehyde or ketone produced by oxidative dehydrogenation of alcohol in the presence of a recreational catalyst to which phosphorus is added, while maintaining the activity of the catalyst with phosphorus or a phosphorus compound. manufacturing method.