KR830001028B1 - Silver catalyst for the production of ethylene oxide - Google Patents

Abstract

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Description

Silver catalyst for the production of ethylene oxide

The present invention relates to a catalyst for use in preparing ethylene oxide from gaseous ethylene and molecular oxygen.

In general, in the production of ethylene oxide by gas phase reaction using a fixed bed type tubular reaction tube, alumina, silicoalumina, magnesia, pumice, zirconia, zirconium, viscosity, ceramic products carrier, natural or artificial graphite, asbestos Depositing or adhering metal silver as a catalyst body together with some kind of promoter or activator (cocatalyst) to an inert refractory carrier composed of natural or artificial zeolite or silicon carbide It was prepared by using an oxygen or oxygen-containing gas and ethylene as a raw material gas for the reaction.

In the prior art, the solid material, ie, the silver catalyst or the carrier, has a specific surface area of 10 m 2 / g or less and a porosity of up to 60% by volume ratio.

In general, specific surface areas are described by LCDRAKE in "Industrial and Enginnering Chemistry-Analytical Editoin" Vol 17, page 782,1945, and "Industrial and Enginnering Chemistry" Vol 7, page 115,1927, and "Proceedings of the National Academy of The so-called Mercury Porosimeter Method described by WASHBURN in USA USA Vol. 7, page 115,1927 and subsequently described by BRUNAUER, EMMET and TELLER in Vol. 60, page 309,1938 of "The Journal of the American Chemical Society" Vol. It is measured by the nitrogen adsorption method known as the method.

It is not enough to select and select a catalyst carrier because of the above conditions alone. The reason for this is that the state of the reaction phase and technical technique used to deposit the metal silver on the carrier is not sufficient. Therefore, it is because the activity, selectivity, and long-term lifetime of the catalyst to ethylene oxide are affected.

It is already known that the use of ethylene in the epoxidation process is carried out in the following two different technical methods for producing a catalyst from a silver compound.

a) coating a silver compound suspended in a liquid on a carrier;

b) Carefully studied Impregnating the carrier with a silver compound solution dissolved in the solvent of choice.

In the above two methods, both should be silver compounds of the kind having the property of easily decomposing the silver compound to precipitate the metallic silver on the carrier.

In addition, the correlation between the silver compound and the solvent used is very important. The reason for the above-described correlation between the silver compound and the solvent is that the structural properties of the carrier and the metal are different from the evaporation process. This is because it has a very important effect on the activity and selectivity of the catalyst. In order to obtain a silver catalyst containing metal silver particles or aggregated particles having a size and shape such that the activity and selectivity to be changed to ethylene oxide are improved to a desired degree, the carrier may be a warm compound or an organic metal silver compound. It is impregnated with a solution, the organometallic compound of which the organic portion of the compound binds one or more nitrogen atoms or oxygen atoms in the molecule, which can form a coordination bond with the atoms of the metal and has an acidic functional group. It is preferable that it be a silver compound (silver salt).

The primary form of the organosilver compound used for such a use is that in which an acidic group and a functional group capable of forming an intramolecular complex with an atom of metal silver are bonded in the same molecule. Examples of this are as described in the claims of French Patent No. 1,295,385, ie impregnating the carrier with an aqueous solution of silver lactic acid, or as claimed by Applicant as No. 77033866 dated November 10, 1977. It may be exemplified by impregnating a silver compound such as anthranilic acid, picolinic acid, or salicylic acid into a carrier by solution solution with pyridine. And the technical content of French Patent No. 2,023,986 dated November 26, 1969 is different from the above, which is to impregnate the carrier with a metal silver derivative of tartaric acid, citric acid, malic acid, or isomalic acid in an aqueous solution state.

In addition, examples of the secondary form used in the above-mentioned applications include the composition of an inorganic silver salt or an organic silver salt with a substance having one or more complexing groups in the molecule which can form coordination bonds with metal silver. The thing which becomes. This includes French Patents Nos. 2,117,183 and 2,271,869 dated November 30, 1971 and 1975.5.16, which consisted of silver oxalate or a mixture of silver carbonate and ethylenediamine and ethanolamine, where possible an aqueous ammonia solution. Formed to form the impregnated into the carrier is to claim. As an example of the preparation method in this regard it was described starting from the compound Ag ₂ (CH ₂ NH ₂ —CH ₂ NH ₂ ) ₂ C ₂ O ₄ .

In French Patent No. 2,253,747 dated January 1, 1978, ammonia is considered to be preferred as a complexing agent for silver carboxylic acid salts, but it has been argued that the addition of reducing amines to aqueous impregnation solutions is important.

로 되는 아민류에서 선택되는 아민과 더불어 분자식이 Ag(amine)₂NO₃인 물질의 수성용액형 착화제와를 사용하였다.In French Patent No. 2,351,700 dated May 8,1977, the general formula

An aqueous solution complexing agent of a substance having a molecular formula of Ag (amine) ₂ NO ₃ together with an amine selected from among amines was used.

In French Patent No. 2,336,974 dated November 23, 1976, it has been published that a special amine complexing agent which can act as a solvent and also as a complexing agent has been explored in order to prepare a silver catalyst from silver carboxylic acid salts. These complexing agents were specific aliphatic polyamines or aliphatic aminoethers such as, for example, diethylenetriamine or bis (2-amino-ethyl) oxide.

In French Patent No. 2,215,267, filed Jan. 24, 1974, pyridine compounds were used as solvents and complexing agents for silver acetate.

The metals thus obtained are characterized in terms of the nature of the crystals, in particular the size, shape and distribution of the particles in the carrier, of 2,271,869 and 2,148,028 and 1977.7.25, dated 1975.5.16. No. 2,352,810 and Belgian Patent No. 852,123 dated April 3, 1977 and PETER HARRIOT and co-researchers described in "Journal of Catalysis" Vol 39 (3), page 395 (1975), Vol 21 (1), page 56 (1971). Mr. J.WU and MM, "The effect of crystallite size on the activity and silver catalysts", published in 1973 at Cornell University in the United States of America. JARJOUI was clearly published in 1976 in the "Study of the partial oxidation of ethylene in contact with silver based catalysts" at the University of Lyon, France.

The present invention provides cyclic iminoethers or isoxazoles (IV) in the form of oxazole (I), 2-oxazoline (II) and 3-oxazoline (III) represented by the following general formula. And cyclic alkyloxyimines of the form of 2-isooxazoline (V) and the like are complexed with salts and impregnated with a carrier to obtain a known heat treatment in an atmosphere of inert, reducing or oxidizing properties. The catalyst was found to have a very high activity and less adverse effects due to the carbon dioxide (CO ₂ ) content in the reactor body, which greatly increased the productivity of the ethylene oxide during the reaction, thereby greatly improving productivity. It is accomplished by doing so.

[Structure of General Formula]

In the general formulas (I) to (V) shown above, R is a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or a phenyl group.

According to the inspection of the silver-silver catalyst obtained by the scanning electron microscope, the particles of the metal silver constituting the catalyst were homogeneous and regular in the distribution state, and the shape was close to the spherical shape, and the diameter ranged from 0.1 to 0.1. It was 1 micron.

The silver catalyst obtained by the present invention is efficiently manufactured by a two-step process described below.

a) A solution of the selected silver compound (silver salts) with a solvent is impregnated into the carrier. This impregnation process involves immersing the carrier in the solution to impregnate the solution with the solution and then removing the excess solution, distilling off the solvent, or dissolving the solution in the carrier under conditions of pressure and temperature at which the solvent can be removed immediately. Or spray the solution continuously onto the carrier.

b) The obtained silver compound impregnated dry carrier is heat-treated to a temperature at which the silver compound in the carrier can produce metal silver.

Various kinds of silver salts are used. Examples thereof include metal nitrate, sulfate, carbonate, formate, lactate, citrate, salicylate, maleate, malate, malonate and phthalic acid. Salts, tartarate, picolinate, anthranilate, salicyaldehyde complex compounds, and the like, in particular, silver salts of organic carboxylic acids having 1-10 carbon atoms and 1 to 2 acidic functional groups. , Silver benzoate, silver oxalate and silver pivalate are all preferably used as silver salts.

The silver salts described above may be replaced by a solution containing silver oxide in the form of an impregnation solution containing an acidic component in a slightly larger amount than the theoretical amount or the theoretical amount capable of producing silver salts. In general, the amount of acid is more than 5 to 25% in molar ratio than theoretical amount.

As a solvent to be used, it is effective to use the novel complexing agent as described above, and the use of the above-mentioned heterocyclic compounds is one of the objectives of the present invention. It has also been found that it is a solubilizer that greatly increases the solubility of the organic ionic compounds in the solvent. The minimum amount of cyclic iminoethers or cyclic alkyloxyimines is 2 molecular weights of the cyclic hetero compounds with respect to 1 atom of metal silver, and the solvent used in the impregnation process is a low-cost solvent, for example. An aqueous solution or an aqueous solution of ammonia, and nitriles, especially ketones such as acetonitrile, acrylonitrile, propionitrile, acetone, or methyl ethyl ketone, lower volatile alcohols, ethylene glycol, diethylene glycol, and amines may be used. Impregnation of the catalyst carrier is carried out with a solution containing as thick as possible from 300 to 400 g / l.

For the carrier having been impregnated, a process of separating and depositing the metal silver from the organic portion contained in the carrier is performed. A particularly preferable treatment method in such a treatment is to carry out the pyrolysis treatment under the following conditions.

In the temperature range from 20 ° C to 280 ° C, the temperature is raised at a rate of 20 ° every hour, and then heat-treated at 280-300 ° C for 10 to 50 hours. This process is carried out in a nitrogen atmosphere, and in this case, it may be carried out in an atmosphere in which an oxidizing agent or a reducing agent, for example, air, oxygen, hydrogen, or formaldehyde is added.

The metal content of the catalyst thus obtained is 5 to 25%, more preferably 8 to 20%.

The nature and tissue structure of the carrier is also important. Commonly used types of refractory carriers include α-alumina, silico-alumina, silicon carbide, zirconium or zirconia. These carriers should be of a size suitable for industrial fixed bed reactors. The shape may be ring, lozenges, chip or small piece, spherical shape or extruded shape ranging in size from 3.2 to 13 mm, and the catalyst is used in the catalytic reaction or the process of handling. Heavy or crumb is one that requires physical and mechanical properties that do not emit dust during the manufacture of the catalyst. The specific surface area of these final products (containing catalysts) is preferably less than 10 m 2 / g and less than 2 m 2 / g, i.e., 0.1 to 1 m 2 / g.

The apparent porosity should be mainly of pores with a radius of 0.25 microns and should have a volume ratio of at least 40 to 50% of the total volume.

In the experiment of the silver-containing catalyst carried out by the present invention, a silico-alumina-type carrier sold by Mr. Norton was used, which was spherical, and the granules were 6.5 to 4.9 mm and the specific surface area was 0.30 m 2 /. g and total porosity of 0.34 cm 3 / g.

The inventors have also confirmed the following facts with respect to the prior art, which will be explained as follows.

a) When a certain kind of compound, such as a halogenated hydrocarbon derivative, is present in a very small amount in the reaction zone, selectivity in the reaction is improved. It is very useful to add to the 1,2-dichloro ethanol reaction zone in the gas volume ratio up to 1 ppm.

b) Known promoters (catalysts) for the metal silver, which is the catalyst body of the silver-containing catalyst, for example K, Ca, Cas, Ba, Pt, Ni, Sn, Ca, Sr, Li, Mg, Na, Rb, Au, Cu, Zn, La, Ce, Th, Be, Sb, Bi, Ti, Pd, Ir, Os, Ru, Fe, Al, etc. can be added in the range of 0 to 2% (weight), which is a usual addition amount. have.

In Examples 1 to 12 described below, the containing catalyst of the present invention and the ethylene oxide side production method are not limited to these examples. Regarding the results obtained in these examples, the total conversion flow path of ethylene was respectively expressed by the following equation.

Total conversion of ethylene (O.E.C.):

OEC =

Rate of conversion to ethylene oxide, i.e. selectivity (E.O.S):

EOS =

Example 1

42.6 g of a granule having a size of 6.5 mm as a carrier of NORTON SA 5239 are charged into a flask of a rotary evaporator. The temperature of the oil bar attached to the rotary evaporator is 130 deg. C and degassed only on the carrier for one hour under reduced pressure. Next, a solution added to 108 g of silver acetate 16.5 gol 2-methyl-2-oxazoline (2-methy-2-oxazoline) is added dropwise to the carrier being stirred in the flask. Under these conditions, the solvent evaporates immediately. After the addition of the solution, the impregnation and drying processes are completed. Therefore, the solution is transferred to a tubular pyrolysis apparatus for heat treatment to precipitate the metal silver from silver acetate. This heat treatment is carried out in a nitrogen atmosphere and heated up to a temperature of 270 ° C. at a rate of 20 ° C. every hour and maintained at 270 ° C. for 18 hours. The obtained content was found to be 17% by weight based on the content of metal silver in the catalyst. Combining X-ray microscopy with scanning electron microscopy revealed that the metal silver particles in the catalyst were regularly distributed in the carrier, pseudo-spherical, and sized from 0.2 to 0.4 microns.

Next, the vessel obtained above is filled with 30 ml of the catalyst obtained in a reaction tube made of stainless steel pipe having a length of 600 mm and an inner diameter of 16 mm. At the lower side of the reaction tube, the reaction tube and the vessel in the reaction tube are fed into a preheating tube made of porcelain pipe having a length of 200 mm in which a catalyst is placed. The whole reactor is heated with a double case oil circulating oil bar. The gas charged and discharged into the reaction tube was analyzed by two-stage detection chromatograph. The first one was flame ionization detector which detects and analyzes ethylene oxide, methane, formaldehyde, propylene, propane, methanol and acetoaldehyde. Fire ionization detection device) and the second is a thermal conductivity detection device for detecting and analyzing oxygen, nitrogen, carbon dioxide, ethylene and water. The two columns were connected in series with ones 2.5m long and 2.5mm (1/8 inch) in diameter. One column was filled with Chromosorb 101 and the other with Porapak Q.

An atmospheric pressure mixed gas mixed with 50%: 50% of air and ethylene is passed into the catalyst bed in the reaction tube for 47 hours between the temperatures of 177 ° C and 185 ° C. Next, the reaction raw material gas containing ethylene, 5% of 13% oxygen, 82% of nitrogen, and 35ppb of 1,2-dichloroethane was reacted at a rate of 9,000 liters (in terms of standard state) per 1 liter of the catalyst. Ethylene oxide manufacturing experiments are performed by passing through the tube. The total conversion of ethylene (O.E.C.) was 5% and the selectivity to ethylene oxide (E.O.S.) was 78.5%.

EXAMPLE

42.6 g of a carrier of NORTON SA 5239 having a granule size of 6.5 mm are charged into the flask as described above, degassed at 100 ° C. under reduced pressure, and then a solution of 16.5 g of silver acetate salt dissolved in 108 g of oxazole is added dropwise. The temperature of the evaporator is set to 100 ° C. and the oxazole in the solution is added dropwise and then distilled soon. Thus, the impregnated carrier was heat-treated in the same manner as in Example 1. It was analyzed that the total amount of metallic silver in the obtained silver catalyst was 16.5%. Examination using X-ray microanalysis in combination with scanning electron microscopy revealed that the metal particles in the carrier were pseudo-spherical and sized in the range of 0.3 to 0.5 microns in diameter.

The reaction vessel described in Example 1 was charged with 30 ml of the silver catalyst obtained above. A gas having a ratio of air and ethylene of 50% to 50% is passed for 30 hours at a temperature of 138 ° C and 184 ° C. Next, ethylene 13%, oxygen 5%, 1,2-dichloroethane 35ppb, and the balance is 20 bar pressure of the reaction raw material gas containing different amounts of CO ₂ and nitrogen, each containing ₁ liter of catalyst. The vessel in the reaction tube passes through the catalyst bed at a rate of 9,000 l per hour (standard). The results thus obtained are listed in Table 1 below.

[Table 1]

As a result, the inclusion catalyst of the present invention can be seen that less adverse effects of carbon dioxide (CO ₂ ), which is an inevitable secondary product during the ethylene oxide manufacturing process.

Example 3

36 g of a carrier of NORTON SA 5239 having a granule size of 4.9 mm were charged into a flask of the rotary evaporator described in Example 1 above and degassed while heating to a temperature of 120 ° C. under reduced pressure. Separately, a solution in which 5 g of acetic acid was dissolved in 100 g of 2-methyl-2-oxazoline and 8.5 g of silver oxide was dissolved to prepare a solution. This solution is added dropwise to the carrier in the flask. The heat treatment as described in Example 1 yields a silver catalyst having a metal silver content of 13.5 wt%. Ethylene 13%, oxygen 5%, nitrogen 82 after activating the catalyst at atmospheric pressure for 48 hours in the temperature range from 182 ° C to 218 ° C in a mixed gas with an ethylene / air ratio of 50% / 50%. %, The reaction mixture gas containing 35 ppb of 1,2-dichloroethane was reacted at a pressure of 20 bar at a flow rate of 9,000 liters (standard conversion) per hour with respect to 1 liter of catalyst. The result of reacting 58 hours at the reaction temperature of 218 ° C was 77% for E.O.S. (selectivity) with respect to 5% for O.E.C. (total conversion).

Example 4

37.5 g of a carrier of NORTON SA 5239 having a granule size of 4.9 mm are charged into a flask of a rotary evaporator. A solution obtained by dissolving 8.9 g of silver oxide in a liquid consisting of 10.3 g of benzoic acid (benzoic acid) and 120 g of 2-methyl-2-oxazoline was treated as described in Example 1 in the above-described preparation to obtain a silver-containing catalyst. After the heat treatment, the metal silver content of the silver catalyst was analyzed to be 14.2 wt%.

Into the reaction tube as described in Example 1, 30 ml of the silver obtained catalyst was charged. Ethylene 13%, Oxygen 5%, Nitrogen 82%, 1,2-Dichloroethane after activating pre-treatment for 114 hours at a temperature of 198 ℃ and 213 ℃ in a mixed gas where the ratio of ethylene / air is 50/50 at atmospheric pressure. A reaction gas of 35 ppb is passed through at a pressure of 20 bar. The velocity ratio of this gas is 9,000 l (standard state) per hour for 1 l of catalyst. The performance performed at the reaction temperature of 232 ° C. showed that the selectivity to ethylene oxide (E.O.S.) was 76.5% with respect to the total conversion of 5%.

Example 5

36.5 g of a carrier of NORTON SA 5239 having a granule size of 4.9 mm was treated with a solution of 8.33 g of pivalic acid and 8.6 g of silver oxide in advance, in a mixed solution of 104 g of 2-methyl-2-oxazoline, as described in Example 1, Ham gets a catalyst. After pyrolysis, the silver content of the silver catalyst was analyzed to be 16.6 wt%. Into the reaction tube described in Example 1, 30 ml of the silver obtained catalyst was charged. A mixture gas having a ratio of air and ethylene of 50/50 is allowed to pass for 48 hours between the temperature range of 184 ° C and 200 ° C. After activating the catalyst, ethylene 13%, oxygen 5%, nitrogen 82% The reaction vessel body of 1, 2-dichloroethane 35ppb is passed through the catalyst bed at a rate of 9,000 l (standard state conversion) every hour. As a result, the reaction temperature was 224 DEG C. The result was 77% of the selectivity to ethylene oxide relative to 3.4% of the total conversion of ethylene.

Example 6

29.5 g of a carrier of NORTON SA 5239 having a granule size of 6.5 mm are charged into a flask of a rotary evaporator. A solution containing 9 g of silver oxide dissolved in a liquid consisting of 28.2 g of 2-methyl-2-oxazoline and 220 ml of acetonitrile was added to the carrier in the flask as in Example 1 to obtain a silver-containing catalyst. After pyrolysis, the metal content of the silver catalyst was analyzed to be 19wt%. In a stainless steel reaction tube 16 mm in diameter and 355 mm in length, 30 ml of the catalyst obtained above was charged and heated with a nitrate application bar. The reaction raw material gas is preheated with a porcelain filling having a height of 42 mm and then fed from the bottom of the reaction tube. The analyzer is the same as that described in Example 1.

An activated mixed gas having an air / ethylene ratio of 50/50 was fed in the temperature range of 157 ° C to 175 ° C for 30 hours to carry out preactivation of the catalyst, followed by ethylene 13%, oxygen 5%, nitrogen 82 %, 1,2-dichloroethane 35 ppb of reaction gas was passed through the catalyst bed at a pressure of 20 bar. The rate of passage was 9,000 liters per 1 liter of silver silver catalyst per hour, and the reaction rate was 195 ° C. The selectivity to ethylene oxide was 77% with respect to 5% of the total conversion of ethylene.

Example 7

36 g of a carrier of NORTON SA 5239 having a granule size of 4.9 mm are charged into a flask of a rotary evaporator. The temperature of the oil bar is maintained at 100 ° C. and the carrier is degassed for 30 minutes under reduced pressure. Separately, 5 g of acetic acid was added to the Erlenmeyer flask where 90 g of oxazole was infused, and 8.6 g of silver oxide was added in a small amount to prepare a liquid. The liquid is stirred for one hour to dissolve the silver oxide sufficiently and then left for half an hour. This solution is then added dropwise to the carrier in the flask and stirred to immediately evaporate the solvent. After the addition of the solution, the impregnated and dried carrier is transferred to the tubular reaction tube for heat treatment to precipitate the metal silver. This heat treatment is carried out for 18 hours at a rate of 20 ° C. per hour up to 270 ° C. in a nitrogen stream. It was confirmed that the metal content of this silver catalyst was 12wt%.

Next, 30 ml of the containing silver catalyst was charged into a stainless steel reaction tube having a length of 600 mm and an inner diameter of 16 mm. It is 200mm long and the inside of the reaction tube is made of porcelain ring in which the catalyst is placed to preheat the reaction raw material gas. The entire reactor is heated with a double oil-bard and oil circulating heating unit. Gas to be fed into and out of the reaction tube is analyzed using a double-detection chromatograph. One is a flame ionization detector for detecting and analyzing ethylene oxide, methane, formaldehyde, propylene, propane, methanol and acetoaldehyde. The other is a thermal conductivity detection device for detecting and analyzing oxygen, nitrogen, carbon dioxide, ethylene and water. These two detectors were connected in series with a diameter of 2.5mm (1/8) and a length of 2.5mm, and chromosorb 101 on one side and Porapak Q on the other side. Fill it.

A mixed gas of air / ethylene of 50/50 is fed to the catalyst in the reaction tube for 48 hours at atmospheric pressure while heating between 156 ° C and 178 ° C. Next, the reaction raw material gas consisting of 13% ethylene, 5% oxygen, 82% nitrogen, and 35ppb of 1,2-dichloroethane was added to the reaction tube at a rate of 9,000l (standard state conversion) per 1l of catalyst. Pass it through the silver catalyst layer. The reaction was carried out at a reaction temperature of 217 ° C. for 45 hours. The selectivity to ethylene oxide was 77.5% based on 5% of the total conversion of ethylene.

Example 8

After dissolving 13.5 g of silver propionic acid salt to 87 g of oxazole, the filtered liquid was degassed at 100 ° C. for 1 hour as it was charged into a flask of a rotary evaporator, and granules were added to 36.5 g of a carrier of NORTON SA 5251 having a size of 4.9 mm. Add it down. When the oil bar temperature is 100 ° C, the oxazole in the solution is distilled off as soon as it is added dropwise. Thus, the carrier after the impregnation process is subjected to heat treatment as described in Example 7. The content of metal silver in this silver catalyst was 12.5%.

A mixed gas having an air / ethylene ratio of 50:50 is passed at atmospheric pressure for 46 hours at a temperature between 140 ° C and 161 ° C. Next, a reaction gas containing 13% of ethylene, 5% of oxygen, 82% of nitrogen, and 35ppb of 1,2-dichloroethane was charged at 20 bar, and 9,000l per hour of standard catalyst was used. At the rate the inclusion of the reaction tube is passed into the catalyst bed. When the reaction temperature was 185 ° C, the selectivity to ethylene oxide was 80% with respect to 5% of the total conversion of ethylene.

Example 9

42.5 g of a carrier of NORTON SA 5239, granule size 6 mm (1/4 inch), is charged into a flask of a rotary evaporator. The pressure of the oil bar was reduced to 120 ° C., and the gas adsorbed by the carrier was degassed for 1 hour. At this time, the solution which melt | dissolved 16.5 g of silver acetate salts in the liquid which becomes 92 g of water and 18 g of oxazole is prepared. Next, the previously prepared solution is added dropwise to the stirring carrier. Next, heat treatment was performed as described in Example 7. The metal content of the catalyst was analyzed to be 11.5 wt%. Into the reaction tube as described in Example 7, 30 ml of the silver obtained catalyst was charged. The introduction of a mixture of air / ethylene 50/50 at atmospheric pressure for 48 hours was completed by activation of the catalyst followed by ethylene 13%, oxygen 5%, nitrogen 82% and 1,2-dichloroethane 35ppb. The reaction raw material gas into the catalyst layer of the reaction tube at a pressure of 20 bar is fed at a rate of 9,000 liters per hour (standard state) per 1 liter of catalyst. The selectivity to ethylene oxide was 77.8% with respect to 4.5% of the total conversion of ethylene by reaction for 50 hours at the reaction temperature of 228 degreeC.

Example 10

36 g of a carrier of CARBORUNDUM SAHT 96, granule size 1/4 inch (about 5-7 mm), are charged into a flask of a rotary evaporator. 14 g of silver acetate salt was dissolved in 94 g of oxazole, and the filtered solution was treated in the same manner as in Example 9 to obtain a catalyst. The metal content of the obtained silver catalyst was analyzed to be 16%. Into a stainless steel reaction tube heated with molten nitrate bar and having an inner diameter of 16 mm and a length of 355 mm, 30 ml of the silver catalyst obtained above is charged. Prior to filling the reaction tube, the reaction raw material gas is preheated with a preheating device filled with porcelain filler having a height of 42 mm, and then supplied from the lower side of the reaction tube. The gas sent to the reaction tube and the gas discharged from the reaction tube are analyzed using an analyzer similar to that described in Example 7. A mixed gas of air / ethylene 50/50 is fed for 48 hours at a temperature between 137 ° C. and 155 ° C. and at atmospheric pressure. Next, the reaction raw material gas containing 13% of ethylene, 5% of oxygen, 82% of nitrogen, and 35ppb of 1,2-dichloroethane was charged at a rate of 20 bar at a rate of 9,000 l (standard conversion) per liter of the catalyst in the reaction tube. It is passed through the reaction tube. When the reaction temperature was 191 ° C., the selectivity was 77% with respect to the total conversion of 5%.

Example 11

14 g of silver acetate was dissolved in 126 g of oxazole, and the prefiltered solution was added to a carrier in a flask mounted on a rotary evaporator filled with 36 g of a carrier of NORTON SA 5236 having a granular size 1/4 inch. This carrier is degassed in advance under reduced pressure for 1 hour and 30 minutes in a heated state. When the oil bar of the rotary evaporator is heated to 80 ° C., the oxazole impregnated in the carrier is distilled off at a reduced pressure of 40 mm from the carrier impregnated with the solution. After the added oxazole was distilled off, a heat treatment similar to that described in Example 7 was performed. The content of metal silver in the obtained silver catalyst was analyzed to be 15.8%.

In the reaction tube as described in Example 10, the above-mentioned containing silver catalyst was charged with 30 ml of the silver containing catalyst, and the air / ethylene ratio was 50:50. The containing gas for activation of the catalyst was placed between 150 ° C and 168 ° C for 48 hours at atmospheric pressure. By passing through the feed, the catalyst is activated, and then the reaction raw material gas of 13% ethylene, 5% oxygen, 82% nitrogen and 35 ppb of 1,2-dichloroethane is fed at a pressure of 20 bar. The total conversion of ethylene was 4% at the reaction temperature of 190 ° C., while the selectivity to ethylene oxide was 70%.

Example 12

42.5 g of a carrier of NORTON SA 5239 with a granule size of 1/4 inch is charged into the flask of the rotary evaporator. The carrier in the flask is degassed under the same conditions as described in Example 7. 16.5 g of silver acetate was dissolved in a mixed solution of 112 g of isoxazole and 27.1 g of water, and then the isoxazole and water were immediately distilled off by dropping the prefiltered impregnation solution into the carrier in the flask. When the dropwise addition of the impregnating solution is completed and drying is completed, heat treatment is performed under the same conditions as those described in Example 7. The content of metal silver in the obtained silver catalyst was titrated to be 12.7%. Into the reaction tube as described in Example 10 was filled with 30 ml of the catalyst was charged with an activated mixed gas of air / ethylene 50/50 in a temperature range of 150 ℃ to 195 ℃ for 48 hours and then ethylene 13 The reaction raw material gas containing 5% of%, 5% of oxygen, 82% of nitrogen, and 35ppb of 1,2-dichloroethane was contained in the reaction tube at a pressure of 20 bar at a rate of 9,000 liters (standard conversion) per hour with respect to 1 liter of catalyst. It is sent to the reaction tube in the reaction. The selectivity to ethylene oxide was 75% with respect to 5% of the total conversion of ethylene at the reaction temperature of 217 degreeC.

Claims (1)

As described in the text, the number of carbon atoms in preparing a silver catalyst for producing ethylene oxide is obtained by impregnating and drying the organometallic silver compound in the refractory carrier for catalyst production, followed by thermal decomposition to precipitate the metal silver on the carrier in a free state. Oxazole, 2-methyl-2-oxazoline, 2-oxazoline, 3-oxazoline, isoxazole, which is three and has one number of oxygen atoms and one number of nitrogen atoms A heterocyclic compound having a heterocyclic group substituted with one or more alkyl groups and / or one or more phenyl groups at a bond carbon of 2-isooxazoline or a heterocyclic group constituting these heterocyclic compounds, Used as a complexing agent with a 1-base silver organic acid silver salt or a dibasic silver organic acid silver salt having 1 to 10 carbon atoms, or as a complexing agent, or a complexing agent The organic metal obtained by using as a zero and without using water, aqueous ammonia solution, nitrile, alcohol, ketone, or amine as a solvent or a solvent is used as a compound solution. A silver-containing catalyst for producing ethylene oxide, characterized by using a silica-alumina-type substance as a carrier, and the metal silver content in the resulting catalyst is in the range of 5 to 25%.