JPS60100533A - Preparation of glyoxal - Google Patents

Abstract

PURPOSE:In preparing glyoxal by oxidizing ethylene glycol in gaseous phase, to obtain the desired compound useful as a treatment for fiber, treatment for paper making, etc. in high yield and in high purity, by using silver having specific particle diameter as a catalyst in the presence of phosphorus or phosphorus compound. CONSTITUTION:In preparing glyoxal by oxidizing ethylene glycol in gaseous phase, the raw material and a gas containing molecular oxygen are brought into contact with a silver catalyst containing >=5wt% particles having <=0.1mm. particle diameter in the presence of 1-50ppm phosphorus or phosphorus compound (preferably relatively low-boiling organic phosphorus compound such as methyl phosphite, etc.) calculated phosphorus based on the raw material at high temperature (450-650 deg.C) with suppressing formation of decomposition and oxidation products such as CO, CO2, HCHO, etc., unreacted raw material, and glycol aldehyde as a reaction intermediate, to give the desired compound having high quality in high yield and selectivity stably.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a gas phase oxidation reaction of ethylene glycol, and more particularly, the present invention relates to a gas phase oxidation reaction of ethylene glycol, and more particularly, a method of contacting ethylene glycol with powdered silver having a fixed particle size in the presence of a predetermined 117 phosphorus or a phosphorus compound ( This is a gas phase oxidation method that produces glyoxal in high yield with r-4'!j characteristics.

There are many proposals for producing glyoxal by oxidizing ethylene glycol. For example, a method of oxidizing with oxygen using a nitrification catalyst consisting of copper and/or silver and phosphorus (1!l Publication No. 1664/1972), a catalyst containing phosphorus and copper, phosphorus and silver, or phosphorus, copper and silver. An oxidation method carried out by mixing a bromine compound in a raw material mixture gas in an amount that does not reduce the conversion rate of ethylene glycol to about 90% or less in the presence of ('13. + Kaimei No. 52-17408)
There is. In addition, a method using a catalyst containing copper (American method, j
' [No. 2.339.282), cu-Si-M1
A method has been proposed in which a copper-containing catalyst is co-f'-4-oxidized with a halogen thread compound using a copper-containing catalyst.

However, methods using these alloy catalysts are not industrially advantageous because the preparation of the catalyst is slow, the lifetime during which high reaction performance can be maintained is short, and the reprocessing of the catalyst is complicated. It wasn't the method.

Furthermore, as a method by oxidation of ethylene glycol,
A method of oxidizing in the presence of chain crystals with a constant particle size (01-2.s vn, ) (q: J Kaimei 54-10.580
No. 9), a method of oxidizing using a copper-containing catalyst in the coexistence of a phosphorus compound that vaporizes under the reaction conditions (Shokai 55-551
No. 29) have also been proposed. However, the yield of glyoxal by these methods is not very high, and a considerable amount of glycolaldehyde and other impurities, which are reaction intermediates, are produced.

Glyoxal is a fiber processing agent, 19 paper strength agent, 11 a main raw material for soil hardening agent, and 17 is a very useful compound as an intermediate for organic synthesis. However, especially when used as a textile processing agent or paper processing agent, if a large amount of glycolaldehyde is added, the final product will be significantly colored and lose its commercial value.

Furthermore, removing glycolaldehyde produced as a by-product during glyoxal production as a post-treatment is too costly and is not an economical method.

Therefore, this method could not compete with the nitric acid oxidation method of acetaldehyde, which has not been implemented industrially.

However, the method for producing glyoxal using ethylene glycol gas-phase acid f
Compared to the FIR f2 conversion method, ethylene glycol with an acid ratio of ethylene (11←'-+ r4) using cheap natural gas as the raw material is used as ) fJ
Although it had excellent uniformity, it was at a disadvantage in this respect.

Therefore, the present inventors proposed a method for producing glyogysal by gas phase oxidation of ethylene glycol in order to overcome the drawbacks of the conventional method.

As a result, we decided to use silver containing particles with a grain size of 01i11111 or more with a coefficient of 5 or more as a catalyst. It has been discovered that not only the yield rate can be dramatically improved, but also that the by-product of glycolaldehyde (1) can be significantly reduced, and that it is possible to produce high-quality products such as /c.

That is, in producing glyoxal by gas-phase oxidation of ethylene glycol, the present invention uses a gas containing ethylene glycol and O/molecular oxygen to phosphorus, and in the coexistence of a phosphorus compound, the particle size is reduced in the upper part. This invention provides a method for producing glyoxal characterized by bringing particles of 01w or less into contact with a silver catalyst containing a coefficient of 5 or more to perform intoxication (!-).

In the present invention, phosphorus or a phosphorus compound may be mixed with ethylene glycol for a predetermined amount before being subjected to the reaction, or may be added to the reaction system separately from ethylene glycol, alone or as a solution. Examples of phosphorus compounds include inorganic phosphorus compounds such as ammonium orthophosphate, diammonium hydrogen phosphate, ammonium dihydrogen orthophosphate, and ammonium dihydrogen phosphite; Various phosphorus compounds such as tertiary phosphine, methyl monononite, phosphorous acid esters such as !+14 ethyl phosphate, methylphosphonic acid/methyl ester, and diethyl ethylphosphonic acid ester can be used effectively. However, phosphorus compounds with a high ?JIi point may cause the evaporator temperature to rise significantly, or these phosphorus compounds may stagnate in the evaporator, decompose, and accumulate, reducing the monthly yield of the device. It is not preferable to use an organic phosphorus compound with a relatively low boiling point, such as phosphorous acid. Methyl, ethyl phosphite, methyl phosphate, ethyl phosphate, etc. are used.

This phosphorus is still the addition of phosphorus compounds; yi, iJ, ethylene glycol is converted to phosphorus,
A range of 0 ppm is suitable. By adding phosphorus or a phosphorus compound, the production of oxidation products such as carbon oxide and carbon dioxide and decomposition products such as formaldehyde is significantly suppressed compared to the case where these are not added, and the desired production is achieved. The yield rate of glyoxal, a substance, is significantly improved. In the method of the present invention, if the addition of phosphorus or phosphorus compounds is temporarily interrupted, the production rate of carbon oxide, carbon dioxide, or formaldehyde immediately increases. This determines that the nitrated phosphorus or phosphorus compound acts effectively in the gas phase rather than accumulating and acting on the catalyst.

In the present invention, the characteristics of the combination of a trace amount of phosphorus or a phosphorus compound and a powdered silver catalyst with a particle size of 0°1 mm or less are determined by the advantages and disadvantages of the action of the phosphorus or phosphorus compound itself and the effects of the powdered silver catalyst itself. Even though their effects are contradictory to each other, by combining the two, the strengths of both interact successfully and a dramatic effect can be achieved.

In other words, increasing the amount of phosphorus compound added without using a powdered silver catalyst reduces the production of carbon dioxide, carbon oxide, and formaldehyde, and improves glyoxal selectivity, but the reaction intermediate glycol Aldehyde and unreacted ethylene glycol increase. On the other hand, in the absence of a phosphorus-stratified phosphorus compound, the particle size is 0.1 m or more compared to the case where chain crystals having a particle size of about 0.1 m or more, which are generally widely used, are used as a catalyst. ．． 1. ', When the following powdered silver is used as a catalyst to carry out the gas phase oxidation reaction of ethylene glycol, the oxidation activity is extremely high and many decomposition oxidation products such as carbon monoxide and carbon dioxide are generated. The yield of the product glyoxal is not very good.

In addition, when phosphorus or a phosphorus compound coexists with a powdered silver catalyst, the increase in glycolaldehyde and unreacted ethylene glycol is significantly suppressed.

On the other hand, when a phosphorus compound is added to ethylene glycol in an amount of about 50 ppm or more in the presence of a conventional chain crystal catalyst having a particle size of about 0.11 m or more, carbon dioxide, -carbon oxide, The generation of decomposition oxidation products such as porn and aldehydes +d decreases, and the glyoxal selectivity improves by -1.
- However, it is not favorable because unreacted ethylene glycol and glycolaldehyde, which is a reaction intermediate, increase. Furthermore, it is not practical because reaction deactivation occurs due to a decrease in the reaction temperature and the stability of reactions 4'' and 5 is significantly impaired. In addition, the reaction stability is significantly improved, and the formation of unreacted ethylene glycol and the 184-mer glycolaldehyde during the reaction is significantly suppressed.

The amount of phosphorus or phosphorus compound to be added is calculated by converting it into ethylene glycol and converting it into phosphorus.Addition of an amount less than 11)I)III will result in a small effect and is not practical. Further, if more than 50 pprn of phosphorus or a phosphorus compound is added in terms of phosphorus, it is not practical because various reaction-inhibiting effects appear to the extent that the reaction cannot be maintained even in the presence of a powdered silver catalyst.

Next, as the powdered silver with a particle size of 0.1 or less used in the method of the present invention, powdered silver obtained by electrolysis may be used, as well as fine powdered silver produced chemically, such as by alkaline precipitation method. It can be used regardless of its preparation method, such as a fine powder obtained by heating yuzu in an inert gas, which is generally called a gas evaporation method.

Such a powdered silver catalyst having a particle size of 0.1 or less can be used alone, but it can also be used in combination with crystalline silver having a particle size of 0.16 or more at a weight ratio of 5% or more.

For example, if the silver particle size is about 0.01 mm to 0.01 mm, it is preferable to use a uniform layer of only those particles.

In addition, when using a fine powder of about 10-5 mm or less, such as that obtained by a vacuum method, in a reactor where the flow of the reaction gas is downward, the lower edge of the powder should have a diameter of about 01 mm or more. A practical example of this is a method in which chain crystals of a commonly used particle size are laid down and a finely powdered silver catalyst is filled on top of the chain crystals, which causes less scattering loss.

Furthermore, instead of silver particles having a particle size of about 0.1 mm or more, an inert carrier with a small specific surface area such as α-alumina or steatite spheres can be used, but the The reaction results obtained are somewhat low. This is because silver has an immediate thermal conductivity. In this way, metal powders such as copper can be used, but iron-based materials that are not catalytic cannot be used.

Furthermore, combinations with silver of other particle sizes VJ, particle size 0.1
m.

The following powdered silver exists 11! (It goes without saying that this is effective.

In the present invention, as molecular oxygen, pure oxygen or air may be used, but economically it is preferable to use the latter.

Furthermore, in order to obtain glyoxal in high yield, ethylene glycol and molecular oxygen are diluted with an inert slag to carry out the reaction. As the inert gas, a rare gas such as nitrogen, helium, or argon, carbon dioxide gas, or water vapor is used.

For the gas phase oxidation of the method of the present invention, a reaction temperature of 450 to 650°C is appropriate.

The reaction scum reacted as described above must be cooled as quickly as possible after leaving the catalyst layer. Excessive retention in the high temperature region will only lead to decomposition of unstable aldehydes. The cooled gas undergoes partial condensation as necessary to recover unreacted ethylene glycol. If there is no unreacted ethylene glycol, or if there is a trace amount of ethylene glycol remaining that does not pose a problem for the product and there is no need to remove it, it is cooled and condensed in a heat exchanger and then returned to normal absorption operations. to separate it from the gas phase components.

The glyoxal aqueous solution thus obtained contains organic acids and trace amounts of formaldehyde as impurities.

This formaldehyde is simply removed by a conventional stripping operation with steam injection, during which time some of the low-boiling organic acids such as formic acid and acetic acid are also removed. Furthermore, an aqueous glyoxal solution obtained by oxidizing ethylene glycol using a powdered silver catalyst contains almost no glycolaldehyde, which is a reaction intermediate, compared to a solution synthesized without using a powdered silver catalyst. In addition, the formaldehyde-stripped aqueous glyoxal solution contains 1 JU, 1 J wiping acid, and 1 J wiping acid, 1 J, and an appropriate acid necessary to maintain the stability of the product. Therefore, if necessary, it is sufficient to perform decolorization treatment and treatment with cation exchange 1V fat.

Thus, according to the method of the present invention, glyoxal can be produced from ethylene glycol in a high yield while suppressing the production of by-products, and the stability of the gas phase oxidation reaction is excellent. Therefore, the present invention is suitable as an industrial method for producing glyoxal.

Next, the present invention will be explained in more detail with reference to Examples.

Example 1 A particle size of 0.00 was obtained by electrolysis of an aqueous silver nitrate solution in a reactor.
45ii' of silver particles of 1 to 0.05 mm were laid down. The packed bed height was approximately 15+nm.

In this reactor, 156 f/Hr of ethylene glycol, 136 t/L-11 of steam, 281 t/Hr of air, 5921/Hr of nitrogen, and 5921/Hr of triethyl phosphite were added to ethylene glycol through an evaporator and a preheater. 26
Bppm (5 ppm as phosphorus) was added and fed in a downward flow, and the reaction was carried out at a reaction temperature of 525°C. After cooling the reaction gas, the product was separated and collected in a water absorption tower.

The results were ethylene glycol conversion rate of 999%, glyoxal selectivity of 811%, formalin selectivity of 2.5%,
The glycolaldehyde selectivity was 0.18%.

Comparative Example-1 No triethyl phosphite was added to the reactor, and the reaction temperature was
When the reaction was carried out under the same conditions as in Example 1 except that the temperature was 92°C, the ethylene glycol conversion rate was 1009, the glyoxal selectivity was 385%, the formalin selectivity was 123%, and the glycolaldehyde selectivity was 0f15 or less.

Example 2 In the bottom layer of the reactor, silver particles with a particle size of 0.35 to 0.84 mm obtained by electrolysis of an aqueous silver nitrate solution were placed in ii and 2y, and above that, silver particles with a particle size of 0.16 to 0.0 mm were placed in the bottom layer of the reactor. ．． ! 11.9f of silver particles of 15 mtn were laid, and the same particle size of IJ1 was used as the top layer.
157 ~0.01 mm silver particles were deposited. Packed bed height i, l: 15 m.

The reaction was carried out under the same conditions as in Example 1 except that the reaction temperature was 517°C.

As a result, ethylene glycol conversion rate was 99.8%, glyoxal selectivity was 79.8%, formalin selectivity was 32%,
The glycolaldehyde selectivity was 026%.

Comparative Example 2 No triethyl phosphite was added to the reactor, and the reaction temperature was
The reaction was carried out under the same conditions as in Example 2 except that the temperature was 85°C.

As a result, ethylene glycol conversion rate was 100%, glyoxal selectivity was 400%, and formalin selectivity was 10.9%.
The N-glycoaldehyde selectivity was 0.05% or less.

Example In the bottom layer of the filter reactor, silver particles with a particle size of OB4-15 obtained by electrolysis of an aqueous silver nitrate solution were placed on 112y, and on top of that, silver particles with a particle size of 035-084 were placed on 97y, and on top of that, silver particles with a particle size of 035-084 were placed on 97y. 7.1 silver particles with a diameter of 0.16 to 0.35 mm
f-laying, with an average grain size of 7 x 10-5 mm as the top layer,
2. Finely powdered silver obtained by vacuum evaporation method. Of laid out. The height of the packed bed was 15 rows.

The reaction was carried out under the same conditions as in Example 1 except that the reaction temperature was 515°C.

As a result, ethylene glycol conversion rate was 998%, glyoxal selectivity was 796%, formalin selectivity was 3.5%,
The glycolaldehyde selectivity was 0.25%.

Comparative Example 3 No triethyl phosphite was added to the reactor, and the reaction temperature was
The reaction was carried out under the same conditions as in Example 6 except that the temperature was 90°C.

As a result, the ethylene glycol conversion rate was 100%, the glyoxal selectivity was 43.0%, the formalin selectivity was 97%,
Glycolaldehyde selection 21S was 0.05% or less.

Comparative Example 4 Is there a silver nitrate aqueous solution in the bottom layer of the reactor? 13. Silver particles with a particle size of 0.84 to 15 obtained by the l□moodjIIIr method were mixed into 13. ii
/, 1127 silver particles with a particle size of 0.35 to OB4 mm are placed on top of that, and the same particle size is 016 to 0.35 as the top layer.
717 mm silver particles were laid down. Filled bed height is 15mm
Met.

The reaction was carried out under the same conditions as in Example 1, except that the reaction temperature was 501°C. As a result, the ethylene glycol conversion rate was 99.7%, the glyoxal selectivity was 765%, the polymerin selectivity was 27%,
Glycolaldehyde selectivity was 1 day.

Furthermore, when the reaction was continued under the same conditions except that the addition of phosphorus fi & l ethyl was stopped, the reaction temperature reached 56.
0°C, ethylene glycol conversion rate 999%, glyoxal selectivity 49.3%, formalin selectivity 7.5
%, and the glycolaldehyde selectivity was 0.15%.

Example 4 Triethyl phosphite vs. ethylene glycol 53.
The reaction was carried out at 506° C. under the same reaction conditions as in Example 1 except that 6 ppm (10 ppm as phosphorus) was added.

As a result, the ethylene glycol conversion rate was 996%, the glyoxal selectivity was 85.6%, and the formalin selectivity was 1.8%.
, the glycolaldehyde selectivity was 0668%.

Example 5 Triethyl phosphite versus ethylene glycol 53.
The reaction was carried out at 500° C. under the same reaction conditions as in Example 6 except that 65 ppm (10 ppm as phosphorus) was added.

As a result, the ethylene glycol conversion rate was 995%, the glyogysal selectivity was 825%, the formalin selectivity was 2.6%,
The glycolaldehyde selectivity was 041%.

Comparative Example 5 Against ethylene glycol! ■-Non-ridged triethyl 55
．． The reaction was carried out at 490° C. under the same reaction conditions as in Comparative Example 4, except that 6 ppm (10 ppm as phosphorus) was added.

As a result, the ethylene glycol conversion rate was 995%, the glyoxal selectivity was 80.0%, the formalin selectivity was 20%,
The glycolaldehyde content was 45%.

patent applicant Mitsui Toatsu Chemical Co., Ltd.

Claims (1)

[Claims] (1) To produce glyoxal by gas-phase oxidation of ethylene glycol, a gas containing ethylene glycol and molecular oxygen is coexisted with phosphorus or a phosphorus compound,
A method for producing glyoxal, which comprises oxidizing it by contacting it with a silver catalyst having a particle size of 0.1 mm or less at a high temperature.