CA1048010A - Catalyst for the production of ethylene oxide - Google Patents
Catalyst for the production of ethylene oxideInfo
- Publication number
- CA1048010A CA1048010A CA210,866A CA210866A CA1048010A CA 1048010 A CA1048010 A CA 1048010A CA 210866 A CA210866 A CA 210866A CA 1048010 A CA1048010 A CA 1048010A
- Authority
- CA
- Canada
- Prior art keywords
- silver
- catalyst
- support
- alkali metal
- catalysts
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D301/00—Preparation of oxiranes
- C07D301/02—Synthesis of the oxirane ring
- C07D301/03—Synthesis of the oxirane ring by oxidation of unsaturated compounds, or of mixtures of unsaturated and saturated compounds
- C07D301/04—Synthesis of the oxirane ring by oxidation of unsaturated compounds, or of mixtures of unsaturated and saturated compounds with air or molecular oxygen
- C07D301/08—Synthesis of the oxirane ring by oxidation of unsaturated compounds, or of mixtures of unsaturated and saturated compounds with air or molecular oxygen in the gaseous phase
- C07D301/10—Synthesis of the oxirane ring by oxidation of unsaturated compounds, or of mixtures of unsaturated and saturated compounds with air or molecular oxygen in the gaseous phase with catalysts containing silver or gold
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/50—Improvements relating to the production of bulk chemicals
- Y02P20/52—Improvements relating to the production of bulk chemicals using catalysts, e.g. selective catalysts
Abstract
Abstract of the Disclosure Silver catalysts for the production of ethylene oxide, prepared by (a) impregnating a support having a surface ares from 0.03 to 10 m2/g with a solution of a compound of K, Rb or Cs to obtain a final catalyst con-taining 0.25-16 mg equivalent weights K, Rb or Cs/kg catalyst for each m2 of support surface per g of support, (b) drying the impregnated support, (c) impregnating the dried support with a solution of a silver compound so as to obtain a final catalyst containing 1-25%w of silver and (d) heating the pro-duct of step (c) to convert the silver compound to silver metal.
Description
- 2 -The invention relates to silver catalysts for the production of ethylene o~ide comprising silver on a porous refractory support and also containing one or more alkali compounds. The invention further relates to a p~ocess for the preparation of these catalysts and to a process for the production of ethylene oxide in the presence of these catalysts.
Materials consisting of silver upon a support are known to be useful catalysts for the production of ethylene oxide by the controlled incomplete oxidation of ethylene with molecu]ar oxygen. A great variety o~ modi~ications have been proposed to improve the activity and selectivity of these catalysts. These modifications have involved, for example, the supports employed, the method of production, the physical form of the silver on the support and the addition of additives to the catalyst.
The alkali metals and their salts have been repeatedly proposed as additives for various silver catalysts for the production of ethylene oxide~ U.S patent specification 2,125,333, an early pub~ication on this subject, discloses "small amounts~' of alkali metals, including both sodium or potassium, in silver catalysts Later patents elaborated on this disclosure, but often with contradictory teachings.
For instance, U.S. patent specification 2,238,474 teaches that while addition of 1000 ppm by weight to 24% by weight of sodium improved silver catalysts, this amount ~8~
of potassium or cesium hydroxide ha~ a detrimental ef~ect on catalyst performance. A large number of promoters useful in broad weight ranges is cited in U.S. patent specification 2,615,900, but no distinction in the effectiveness of the various promoters is made.
The use of large amounts of alkali metal sulphates is stated in U.S. patent specification 2,671,764. Further, U.S. patent specification 2,765,283 discloses that the addition from 1 to 2000 ppm by weight of an inorganic chlorine compound (e.g. sodium chloride) to the catalyst support prior to the addition of silver improves the performance of the finished catalyst. However, U.S.
patent specification 2,799,687 discloses that when from 20 ppm by weight to 1. 6% by weight of an inorganic halide (sodium chloride or preferably potassium chloride) are added as separate solid particles to a fluidized bed of a supported silver catalyst, the halide acts as a suppressant, inhibiting the catalyst activity.
In U.S. patent specification 3,144,416 a number of promoter materials is cited, but no critical limitations on their concentration is given. The use o~ alkali and alkali earth metals as promoters is generally disclosed in U.S.patent specification 3,563,913, listing specifically lithium with no reference to cesium, rubidium or potassium.
These promoters are preferably added to the catalyst support before the latter is impregnated with the solution containing the silver compound. The use of aluminium 10~8(~
oxide supports having a pore volume between 0.15 and 0.30 m /g and a surface area below 10 m2/g is stated in U.S.patent specification 3~575,888. The use of certain organic amine solubilizing/reducing agents to produce uniformly spaced, adherent, hemispherical deposits of metallic silver on catalyst supports is disclosed in U.S.patent speci~ication 3,702,259. According to Netherlands patent application 7300162, catalysts may be used that contain one or more of the alkali metals potassium, rubidium and/or cesium in an amount of 0~35-3,0 milligramatom alkali metal (mgat) per kg catalyst, which metals have been deposited simultaneously with the silver on the catalyst support. Adding potassium, rubidium and/or cesium in amounts outside the range specified is not beneficial and addition of the alkali prior to the;addition of silver offers little or no advantage.
The prior art clearly recognizes that alkali metal compound addition changes, for better or worse, the character of a silver ekhylene oxide catalyst.
It has now been found that the deposition of ~otassium, rubidium or cesium prior to the deposition of the silver in critical amounts proportlonal to the support surface area produces superior ethylene oxide catalysts.
The invention may be defined as relating to silver catalysts for the production of ethylçne oxide comprising silver and one or more alkali compounds on a porous refractory support, which catalysts have been prepared by a process comprising the following steps:
(a) impregnating a porous refractory support having a surface area from 0.03 m2/g to 10 m2/g with a solution of a compound of an alkali metal having an atomic number from 19 through 55 in such concentration as to produce - optionally after extraction with a solvent after either step (b) or (c) indicated below - i.n the final catalyst a content from 0.25 to 16 milligram equivalent weights of the alkali metal per kilogram total catalyst for each square meter of support surface area per gram of catalyst support((mgew/kg)/(m2/g));
(b) at least partially drying the impregnated support f step ta);
(c) contacting the product of step (b) with a liquid phase containing a dissolved silver compound or a slurry of particles of silver or a silver compound in an amount sufficient to deposit from 1 to 25 per cent by weight of silver, based on the total catalyst, on the support surface, and (d) ithermally treating the product of step (c), to convert the silver compound to silver metal.
The catalysts according to the present invention comprise a porous refractory support having deposited on its exterior and interior tpore) surfaces from 1 to 25% by weight, based on total catalyst, of silver ~14~0~0 and certain amounts of potassium, rubidium and/or cesium ions Of the alkali metals, i.e. lithium, sodium, potassium, rubidium and cesium, only those alkali metals of atomic number from 19 through 55 inclusive, i.e., potassium, rubldium and cesium, are suitable. Unless otherwise stated, these three suitable metals will hereinafter be referred to as "the higher alkali metals". Excellent results are achieved with each of the three higher alkali metals. Potassium offers cost advantages, while cesium gives the greatest catalyst improvement. Rubidium gives a greater catalyst improvement than does potassium.
Mixtures of the higher alkali metals are also useful.
The higher alkali metals are present on the catalysts in the f~rm of their cations, rather than as the extremely active free alkali metals. Silverj on the other hand, is present on the finished catalysts as silver metal.
The amount of the higher alkali metal (or metals) present on the catalyst surface is a critical function of the surface area. The contents of higher alkali metals of this invention are found to be directly proportional to the surface area of the support with the optimum content being preferably 5-4 and more preferably 5-3 milligram equivalent weight per kilogram total catalyst for each square meter of surface area per gram of catalyst support ((mgew/kg)/(m /gm)). In other words, the optimum higher alkali metal content divided by the surface area is approximately a constant value. It has been ~L~48~
found that as the alkali metal content is increased from zero, the selectivity of the catalyst increases to a maximum, and at contents beyond the maximum the selectivity decreases again. The content at which this maximum in the selectivity occurs is referred to herein as the optimum alkali metal content. Further, since the approach to the optimum selectivity is gradual rather than a step function, there are alkali metal contents both above and below the optimum that also produce commercially significant improvements in catalyst selectivity and are considered within the scope of this invention. Hence, the alkali metal contents preferably include contents that range from 25% to 175% of the optimum content~ more preferably from 25% to 150%, and most preferably from 50% to 150%. Expressed as the operable range, the higher alkali metal contents, relative to the support surface area range from 0.25 to 16, preferably from 0.25 to 14 and most preferably from 0.5 to 14 milligram equivalent weights per kilogram total catalyst for each square meter of surface area per gram of catalyst support (mgew/kg)/(m ~gm). There appears to be minor variations in the content range of each of the higher alkali metals of this invention wherein optimum selectivity is obtained when the catalysts of this invention are employed in the partial oxidation of ethylene to ethyl~ne oxide. It is thought, however, that these minor differences are attributable to undetermined experimental differences or other unknown variables, ~Lai48~L0 but they are not considered to be significant. While the optimum alkali metal content is directly proportional to the surface area of the cata]yst support, not all surface areas provide commercially useful catalysts.
The catalyst surface areas that have been found critical for this invention range from 0.03 to 10 square meters per gram (m2/g).
It must be made clear that the amounts of potassium, rubidium and/or cesium deposited are not necessarily the total amounts of these metals present in the catalysts.
They are the amounts of these alkali metals which are present on the surface of the catalyst and which are intentionally added to the catalysts prior to the addition of silver. It is not unusual that substantial amounts, often up to 1 %w, of higher alkali metals (usually potassium) are present within the porous support, due to use of support materials containing naturally occurring alkali metals or inadvertent alkali metal addition during support manufacture. These amounts of higher alkali metal present in the support in non-leachable form do not appear to contribute to the improved performance of catalysts aocordin~ to this invention and are neglected in determination of alkali metal concentrations. However, amounts of higher alkali metal present in the support in leachable form must be taken into account in determinlng the amounts of higher alkali metal depos'ited on the support. In fact, an alternate method of providing all or part of the desired amounts of t~e higher alkall metal is to incorporate the higher alkali metal in the support in leachable form during the manufacture of the support.
The catalysts according to the present invention contain from 1 to 25% by weight, based on the total catalyst, of silver as silver metal. Preferably, they contain from 2 to 20 and most preferably from 4 to 16% by weight of silver. The use of amounts of silver larger than 25% by weight is not excluded but is generally economically unattractive. The silver is deposited over the interior and exterior surfaces of the catalyst support and should be evenly dispersed over these surfaces.
The exact physical form of the silver upon the support can vary and does not appear to be critical to the invention. Very excellent results are obtained with the controlled surface alkali metal content catalyst of this invention, however, when the silver is present in the form of uniformly spaced, discontinuous, adherent, discrete particles having a uni~orm diameter of less than one micron (10,000 A). Best results are obtained with this type of catalyst when the silver particles have diameters of from 1000 to 10,000 A and most preferred catalysts have silver particles of an average diameter-in the range of from 1500 to 7500 A.
The support employed in the catalysts according to the invention is selected from the large number .
~8~0 of conventional porous refractory catalyst carriers or support materials which are essentially inert in the presence of the ethylene oxidation feeds, pro-ducts and reaction conditions. Such conventional materials may be of natural or synthetic origin and preferably are of a macroporous structure, that is, a structure having a surface area below 10 m2/g and preferably below 7 m /g.
These support materials typically have an apparent porosity of greater than 20%, Very suitable supports comprise those of siliceous and/or aluminous composition. Specific examples of suitable supports are the aluminium oxides ~including the materials sold under the trade mark "Alundum"), charcoal, pumice, magnesia, zirconia, kieselguhr, fuller's earth, silicon carbide, porous agglomerates comprising silicon and/or silicon carbide, magnesia, selected clays, artificial and natural zeolites and ceramics. Refractory supports particularly useful in preparation of catalysts according to the present invention comprise the aluminous materials, in particular those con-taining alpha-alumina. In the case of alpha alumina-containing supports, pre-ference is given to those having a specific surface area as measured by the B.E.T. method of from 0.1 to 7 m2!g and an apparent porosity as measured by conventional mercur~ or water absorption techniques of from 10% to 50% by volume. The B.E.T. method for determining specific surface area is described in detail in Brunauer, -- 10 _ ~., ~[)4~3010 S., Emmett,P.H., and Teller,E., J.Am.Chem.Soc.,60 (1938), 309-319.
Regardless of the character of the support used, it is preferably shaped into particles, chunks, pieces, pellets, rings, spheres, and the like, of a size suitable for employent in fixed bed applications. Conventional commercial fixed bed ethylene oxidation reactors are typically in the form of a plurality of parallel elongated tubes (in a suitable shell) approximately 2.5 to 5 cm in diameter and 7 to 14 m long filled with catalyst.
In such reactors, it is desirable to employ a support formed into a rounded shape, such as, for example, spheres, pellets, rings, tablets, and the like,having diameters of from 2.5 to 20 mm.
The catalysts of the invention are prepared by a technique in which the desired higher alkali metal is deposited on the catalyst support surface prior to the deposition o~ the silver. Accordingly, the invention also relates to a process for the preparation of silver catalysts according to the invention, which comprises:
(a) impregnating a porous refractory support having a surface area from 0.03 m2/g to 10 m2/g with a solution of a compound of an alkali metal having an atomic number from 19 through 55 in such concentration as to produce - optionally after extraction with a solvent after either step (b) or (c) indicated below - in the final catalyst a content from - 12 ~-~4~
0.25 to 16 milligram equivalent weights of zhe alkali metal per kilogram total catalyst for each square metre of support surface area per gram of catalyst support ((mgew/kg)/(m2/g));
(b) at least partially drying the impregnated support of step (a);
(c) contacting the product of step (b) with a liquid phase containing a dissolved silver compound or a slurry of particles of silver or a silver compound to deposit from 1 to 25 per cent by weight of silver, based on the total catalyst, on the support surface, and (d) thermally treating the product of step (c); to convert the silver compound to silver metal.
The exact concentrations of higher alkali metal compounds and silver compounds employed in the impregnatin~
solution used in the above-mentioned steps (a) and (c) may generally require some routine experimentation since the amount of higher alkali metal compounds and silver compounds deposited will depend in part on the porosity and surface area of the catalyst support.
However, methods of varying the amount of a higher alkali metal and silver deposited are conventional, as is the analytical determination of the amount of 5 the materials actually present.
Preferably the impregnating liquid in step (a) above contains the higher alkali metal compound in such concentration as to produce in the final product a higher alkali metal content from 0.25 to 14 and most preferably from 0O50 to 14 milligram equivalent weights per kilogram total catalyst for each square meter of support surface area.
Another method involves deposition of larger then required amounts of the higher alkali metal salts according to step (a) in the general procedure described above followed by contacting the catalyst particles so obtained after either step (b) or step (d) of the procedure described above with a suitable solvent, for example an anhydrous alkanol of 1 or 2 carbon atoms per molecule, methyl or ethyl acetate or tetrahydrofuran. The higher alkali metals are soluble in the solvents described to a sufficient degree that one or more washings with these solvents will selectively remove the excess higher alkali metal such that the amount remaining intact on the support surface falls within the concentration range critical to the invention. This method then provides a ready means of adjus~ing the higher alkali metal concentration from levels in excess of the content of 16 (mgew/kg)/(m2/g), whether the result of purposeful or inadvertent actions~ to specific concentrations within the range of from 0.25 to 16 (mgew/kg)/(m2/g), by a process whîch is readily applicable to large plant scale operations.
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An excellent method for adding the desired higher alkali metals ls to dissolve a compound thereof in an aqueous phase in an amount regulated to give the required alkali metal addition to the finished catalyst when the support is contacted therewith. Suitable higher alkali metal compounds generally include all those which are soluble in an aqueous phase. In this regard, no unusual effectiveness is observed with use of any particular anion in the alkali metal compounds. For example, hydroxides, nitrates, nitrites~ chlorides, iodidesl bromates, bicarbonates, oxalates, acetates, tartrates, lactates or isopropoxides, may be used.
The support after impregnation with the higher alkali metal may be dried in any suitable manner, preferably by increasing the temperature to a value between 100C
and 200C, for example for a time from 0.5 to 8 and particularly from 0.5 to 4 hours with multiple temperatures being suitable and conducting an inert gas over the heated support. Suitable inert gases are nitrogen, air, hydrogen, noble gases, carbon dioxide, methane and mixtures of these gases. Drying can be performed at atmospheric, sub-, and super-atmospheric pressures.
Vacuum- and freeze-drying may also suitably be employed.
A great variety of methods for adding silver to supports are known. In a typical method, the support may be impregnated with an a~ueous solution of silver nitrate, dried, and the silver reduced with hydrogen ~L~48~1~
or hydrazine as described in U.S. Patent Specification
Materials consisting of silver upon a support are known to be useful catalysts for the production of ethylene oxide by the controlled incomplete oxidation of ethylene with molecu]ar oxygen. A great variety o~ modi~ications have been proposed to improve the activity and selectivity of these catalysts. These modifications have involved, for example, the supports employed, the method of production, the physical form of the silver on the support and the addition of additives to the catalyst.
The alkali metals and their salts have been repeatedly proposed as additives for various silver catalysts for the production of ethylene oxide~ U.S patent specification 2,125,333, an early pub~ication on this subject, discloses "small amounts~' of alkali metals, including both sodium or potassium, in silver catalysts Later patents elaborated on this disclosure, but often with contradictory teachings.
For instance, U.S. patent specification 2,238,474 teaches that while addition of 1000 ppm by weight to 24% by weight of sodium improved silver catalysts, this amount ~8~
of potassium or cesium hydroxide ha~ a detrimental ef~ect on catalyst performance. A large number of promoters useful in broad weight ranges is cited in U.S. patent specification 2,615,900, but no distinction in the effectiveness of the various promoters is made.
The use of large amounts of alkali metal sulphates is stated in U.S. patent specification 2,671,764. Further, U.S. patent specification 2,765,283 discloses that the addition from 1 to 2000 ppm by weight of an inorganic chlorine compound (e.g. sodium chloride) to the catalyst support prior to the addition of silver improves the performance of the finished catalyst. However, U.S.
patent specification 2,799,687 discloses that when from 20 ppm by weight to 1. 6% by weight of an inorganic halide (sodium chloride or preferably potassium chloride) are added as separate solid particles to a fluidized bed of a supported silver catalyst, the halide acts as a suppressant, inhibiting the catalyst activity.
In U.S. patent specification 3,144,416 a number of promoter materials is cited, but no critical limitations on their concentration is given. The use o~ alkali and alkali earth metals as promoters is generally disclosed in U.S.patent specification 3,563,913, listing specifically lithium with no reference to cesium, rubidium or potassium.
These promoters are preferably added to the catalyst support before the latter is impregnated with the solution containing the silver compound. The use of aluminium 10~8(~
oxide supports having a pore volume between 0.15 and 0.30 m /g and a surface area below 10 m2/g is stated in U.S.patent specification 3~575,888. The use of certain organic amine solubilizing/reducing agents to produce uniformly spaced, adherent, hemispherical deposits of metallic silver on catalyst supports is disclosed in U.S.patent speci~ication 3,702,259. According to Netherlands patent application 7300162, catalysts may be used that contain one or more of the alkali metals potassium, rubidium and/or cesium in an amount of 0~35-3,0 milligramatom alkali metal (mgat) per kg catalyst, which metals have been deposited simultaneously with the silver on the catalyst support. Adding potassium, rubidium and/or cesium in amounts outside the range specified is not beneficial and addition of the alkali prior to the;addition of silver offers little or no advantage.
The prior art clearly recognizes that alkali metal compound addition changes, for better or worse, the character of a silver ekhylene oxide catalyst.
It has now been found that the deposition of ~otassium, rubidium or cesium prior to the deposition of the silver in critical amounts proportlonal to the support surface area produces superior ethylene oxide catalysts.
The invention may be defined as relating to silver catalysts for the production of ethylçne oxide comprising silver and one or more alkali compounds on a porous refractory support, which catalysts have been prepared by a process comprising the following steps:
(a) impregnating a porous refractory support having a surface area from 0.03 m2/g to 10 m2/g with a solution of a compound of an alkali metal having an atomic number from 19 through 55 in such concentration as to produce - optionally after extraction with a solvent after either step (b) or (c) indicated below - i.n the final catalyst a content from 0.25 to 16 milligram equivalent weights of the alkali metal per kilogram total catalyst for each square meter of support surface area per gram of catalyst support((mgew/kg)/(m2/g));
(b) at least partially drying the impregnated support f step ta);
(c) contacting the product of step (b) with a liquid phase containing a dissolved silver compound or a slurry of particles of silver or a silver compound in an amount sufficient to deposit from 1 to 25 per cent by weight of silver, based on the total catalyst, on the support surface, and (d) ithermally treating the product of step (c), to convert the silver compound to silver metal.
The catalysts according to the present invention comprise a porous refractory support having deposited on its exterior and interior tpore) surfaces from 1 to 25% by weight, based on total catalyst, of silver ~14~0~0 and certain amounts of potassium, rubidium and/or cesium ions Of the alkali metals, i.e. lithium, sodium, potassium, rubidium and cesium, only those alkali metals of atomic number from 19 through 55 inclusive, i.e., potassium, rubldium and cesium, are suitable. Unless otherwise stated, these three suitable metals will hereinafter be referred to as "the higher alkali metals". Excellent results are achieved with each of the three higher alkali metals. Potassium offers cost advantages, while cesium gives the greatest catalyst improvement. Rubidium gives a greater catalyst improvement than does potassium.
Mixtures of the higher alkali metals are also useful.
The higher alkali metals are present on the catalysts in the f~rm of their cations, rather than as the extremely active free alkali metals. Silverj on the other hand, is present on the finished catalysts as silver metal.
The amount of the higher alkali metal (or metals) present on the catalyst surface is a critical function of the surface area. The contents of higher alkali metals of this invention are found to be directly proportional to the surface area of the support with the optimum content being preferably 5-4 and more preferably 5-3 milligram equivalent weight per kilogram total catalyst for each square meter of surface area per gram of catalyst support ((mgew/kg)/(m /gm)). In other words, the optimum higher alkali metal content divided by the surface area is approximately a constant value. It has been ~L~48~
found that as the alkali metal content is increased from zero, the selectivity of the catalyst increases to a maximum, and at contents beyond the maximum the selectivity decreases again. The content at which this maximum in the selectivity occurs is referred to herein as the optimum alkali metal content. Further, since the approach to the optimum selectivity is gradual rather than a step function, there are alkali metal contents both above and below the optimum that also produce commercially significant improvements in catalyst selectivity and are considered within the scope of this invention. Hence, the alkali metal contents preferably include contents that range from 25% to 175% of the optimum content~ more preferably from 25% to 150%, and most preferably from 50% to 150%. Expressed as the operable range, the higher alkali metal contents, relative to the support surface area range from 0.25 to 16, preferably from 0.25 to 14 and most preferably from 0.5 to 14 milligram equivalent weights per kilogram total catalyst for each square meter of surface area per gram of catalyst support (mgew/kg)/(m ~gm). There appears to be minor variations in the content range of each of the higher alkali metals of this invention wherein optimum selectivity is obtained when the catalysts of this invention are employed in the partial oxidation of ethylene to ethyl~ne oxide. It is thought, however, that these minor differences are attributable to undetermined experimental differences or other unknown variables, ~Lai48~L0 but they are not considered to be significant. While the optimum alkali metal content is directly proportional to the surface area of the cata]yst support, not all surface areas provide commercially useful catalysts.
The catalyst surface areas that have been found critical for this invention range from 0.03 to 10 square meters per gram (m2/g).
It must be made clear that the amounts of potassium, rubidium and/or cesium deposited are not necessarily the total amounts of these metals present in the catalysts.
They are the amounts of these alkali metals which are present on the surface of the catalyst and which are intentionally added to the catalysts prior to the addition of silver. It is not unusual that substantial amounts, often up to 1 %w, of higher alkali metals (usually potassium) are present within the porous support, due to use of support materials containing naturally occurring alkali metals or inadvertent alkali metal addition during support manufacture. These amounts of higher alkali metal present in the support in non-leachable form do not appear to contribute to the improved performance of catalysts aocordin~ to this invention and are neglected in determination of alkali metal concentrations. However, amounts of higher alkali metal present in the support in leachable form must be taken into account in determinlng the amounts of higher alkali metal depos'ited on the support. In fact, an alternate method of providing all or part of the desired amounts of t~e higher alkall metal is to incorporate the higher alkali metal in the support in leachable form during the manufacture of the support.
The catalysts according to the present invention contain from 1 to 25% by weight, based on the total catalyst, of silver as silver metal. Preferably, they contain from 2 to 20 and most preferably from 4 to 16% by weight of silver. The use of amounts of silver larger than 25% by weight is not excluded but is generally economically unattractive. The silver is deposited over the interior and exterior surfaces of the catalyst support and should be evenly dispersed over these surfaces.
The exact physical form of the silver upon the support can vary and does not appear to be critical to the invention. Very excellent results are obtained with the controlled surface alkali metal content catalyst of this invention, however, when the silver is present in the form of uniformly spaced, discontinuous, adherent, discrete particles having a uni~orm diameter of less than one micron (10,000 A). Best results are obtained with this type of catalyst when the silver particles have diameters of from 1000 to 10,000 A and most preferred catalysts have silver particles of an average diameter-in the range of from 1500 to 7500 A.
The support employed in the catalysts according to the invention is selected from the large number .
~8~0 of conventional porous refractory catalyst carriers or support materials which are essentially inert in the presence of the ethylene oxidation feeds, pro-ducts and reaction conditions. Such conventional materials may be of natural or synthetic origin and preferably are of a macroporous structure, that is, a structure having a surface area below 10 m2/g and preferably below 7 m /g.
These support materials typically have an apparent porosity of greater than 20%, Very suitable supports comprise those of siliceous and/or aluminous composition. Specific examples of suitable supports are the aluminium oxides ~including the materials sold under the trade mark "Alundum"), charcoal, pumice, magnesia, zirconia, kieselguhr, fuller's earth, silicon carbide, porous agglomerates comprising silicon and/or silicon carbide, magnesia, selected clays, artificial and natural zeolites and ceramics. Refractory supports particularly useful in preparation of catalysts according to the present invention comprise the aluminous materials, in particular those con-taining alpha-alumina. In the case of alpha alumina-containing supports, pre-ference is given to those having a specific surface area as measured by the B.E.T. method of from 0.1 to 7 m2!g and an apparent porosity as measured by conventional mercur~ or water absorption techniques of from 10% to 50% by volume. The B.E.T. method for determining specific surface area is described in detail in Brunauer, -- 10 _ ~., ~[)4~3010 S., Emmett,P.H., and Teller,E., J.Am.Chem.Soc.,60 (1938), 309-319.
Regardless of the character of the support used, it is preferably shaped into particles, chunks, pieces, pellets, rings, spheres, and the like, of a size suitable for employent in fixed bed applications. Conventional commercial fixed bed ethylene oxidation reactors are typically in the form of a plurality of parallel elongated tubes (in a suitable shell) approximately 2.5 to 5 cm in diameter and 7 to 14 m long filled with catalyst.
In such reactors, it is desirable to employ a support formed into a rounded shape, such as, for example, spheres, pellets, rings, tablets, and the like,having diameters of from 2.5 to 20 mm.
The catalysts of the invention are prepared by a technique in which the desired higher alkali metal is deposited on the catalyst support surface prior to the deposition o~ the silver. Accordingly, the invention also relates to a process for the preparation of silver catalysts according to the invention, which comprises:
(a) impregnating a porous refractory support having a surface area from 0.03 m2/g to 10 m2/g with a solution of a compound of an alkali metal having an atomic number from 19 through 55 in such concentration as to produce - optionally after extraction with a solvent after either step (b) or (c) indicated below - in the final catalyst a content from - 12 ~-~4~
0.25 to 16 milligram equivalent weights of zhe alkali metal per kilogram total catalyst for each square metre of support surface area per gram of catalyst support ((mgew/kg)/(m2/g));
(b) at least partially drying the impregnated support of step (a);
(c) contacting the product of step (b) with a liquid phase containing a dissolved silver compound or a slurry of particles of silver or a silver compound to deposit from 1 to 25 per cent by weight of silver, based on the total catalyst, on the support surface, and (d) thermally treating the product of step (c); to convert the silver compound to silver metal.
The exact concentrations of higher alkali metal compounds and silver compounds employed in the impregnatin~
solution used in the above-mentioned steps (a) and (c) may generally require some routine experimentation since the amount of higher alkali metal compounds and silver compounds deposited will depend in part on the porosity and surface area of the catalyst support.
However, methods of varying the amount of a higher alkali metal and silver deposited are conventional, as is the analytical determination of the amount of 5 the materials actually present.
Preferably the impregnating liquid in step (a) above contains the higher alkali metal compound in such concentration as to produce in the final product a higher alkali metal content from 0.25 to 14 and most preferably from 0O50 to 14 milligram equivalent weights per kilogram total catalyst for each square meter of support surface area.
Another method involves deposition of larger then required amounts of the higher alkali metal salts according to step (a) in the general procedure described above followed by contacting the catalyst particles so obtained after either step (b) or step (d) of the procedure described above with a suitable solvent, for example an anhydrous alkanol of 1 or 2 carbon atoms per molecule, methyl or ethyl acetate or tetrahydrofuran. The higher alkali metals are soluble in the solvents described to a sufficient degree that one or more washings with these solvents will selectively remove the excess higher alkali metal such that the amount remaining intact on the support surface falls within the concentration range critical to the invention. This method then provides a ready means of adjus~ing the higher alkali metal concentration from levels in excess of the content of 16 (mgew/kg)/(m2/g), whether the result of purposeful or inadvertent actions~ to specific concentrations within the range of from 0.25 to 16 (mgew/kg)/(m2/g), by a process whîch is readily applicable to large plant scale operations.
~L~4~ O
An excellent method for adding the desired higher alkali metals ls to dissolve a compound thereof in an aqueous phase in an amount regulated to give the required alkali metal addition to the finished catalyst when the support is contacted therewith. Suitable higher alkali metal compounds generally include all those which are soluble in an aqueous phase. In this regard, no unusual effectiveness is observed with use of any particular anion in the alkali metal compounds. For example, hydroxides, nitrates, nitrites~ chlorides, iodidesl bromates, bicarbonates, oxalates, acetates, tartrates, lactates or isopropoxides, may be used.
The support after impregnation with the higher alkali metal may be dried in any suitable manner, preferably by increasing the temperature to a value between 100C
and 200C, for example for a time from 0.5 to 8 and particularly from 0.5 to 4 hours with multiple temperatures being suitable and conducting an inert gas over the heated support. Suitable inert gases are nitrogen, air, hydrogen, noble gases, carbon dioxide, methane and mixtures of these gases. Drying can be performed at atmospheric, sub-, and super-atmospheric pressures.
Vacuum- and freeze-drying may also suitably be employed.
A great variety of methods for adding silver to supports are known. In a typical method, the support may be impregnated with an a~ueous solution of silver nitrate, dried, and the silver reduced with hydrogen ~L~48~1~
or hydrazine as described in U.S. Patent Specification
3,575,888. In another technique the support may be impregnated with an ammoniacal solution of silver oxalate or carbonate and the silver metal formed by thermally 5 decomposing the salt. Silver may be added as well by the technique disclosed in U.S. Patent Specification 3,702,259, wherein the support is impregnated with special aqueous solutions of silver salts and combinations of ammonia, vicinal alkanolamines and/or vicinal alkyldiamines, and then thermally treated. Other possible methods for adding silver include impregnating a support with an ethanolamine-containing solution of a silver salt and then reducing, as disclosed by Japanese Patent Specification 19606/1971, or by adding a slurry of ~ine particles of silver carbonate to the support and thermally decomposing as described in U.S.Patent Specification 3,043,854 or adding silver in the form of "cluster"
silver as by the process described in U.S.Patent Specification 3,781,317~ In each of these techniques, silver is added to the support when the support is contacted with a liquid phase containing either a silver solution or a slurry of particles o~ silver or a silver compound.
A particularly effective method of depositing the silver is where the silver is added to the support from a basic solution, particularly from a nitrogenous base-containing basic solution. Examples of these nitrogenous bases are ammonia, the alkylamines and the alkanolamines.
~(~148~
In a particularly preferred modification, the silver addition to the catalyst support is rnade by techniques such as those disclosed in U.S.Patent Specification 3,702,259. This preferred preparation method involves impregnation of an alumina support with certain aqueous silver salt solutions and a subsequent thermal reduction of the silver salt. The silver impregnation solution consists essentially of:
A.a silver salt of a carboxylic acid, B. an organic amine alkaline solubilizing/reducing agent, and C. an additional aqueous solvent as is required to achieve the desired silver level.
Suitable carboxylic acid silver salts include silver carbonate and the silver salts of mono- and polybasic carboxylic and hydroxycarboxylic acids of up to about 16 carbon atoms per molecule. Silver carbonate and silver oxalate are particularly useful silver salts, with silver oxalate being most preferred.
An organic amine solubilizing/reducing agent is present in the impregnating solution used in this prepration method. Suitable organic amine silver-solubilizing/reducing agents include lower alkylenediamines of from 1 to 5 carbon atoms per molecule, mixtures of a lower alkanolamine of from 1 to 5 carbon atoms with a lower alkylenediamine of from 1 to 5 carbon atoms, as well as mixtures of ~0480~(~
ammonia with lower alkanolamines or lower alkylene-diamines of from 1 to 5 carbons. Four groups of organic amine solubilizing/reducing agents are preferred. They are the following:
A. vicinal alkylenediamines of from 2 to 4 carbon atoms, B. mixtures of (1) vicinal alkanolamines of from 2 to 4;carbon atoms and (2) vicinal alkylenediamines of from 2 to 4 carbon atoms;
C. mixtures of vicinal alkylenediamines of from 2 to 4 carbon atoms and ammonia; and D. mixtures of vicinal alkanolamines of from 2 to
silver as by the process described in U.S.Patent Specification 3,781,317~ In each of these techniques, silver is added to the support when the support is contacted with a liquid phase containing either a silver solution or a slurry of particles o~ silver or a silver compound.
A particularly effective method of depositing the silver is where the silver is added to the support from a basic solution, particularly from a nitrogenous base-containing basic solution. Examples of these nitrogenous bases are ammonia, the alkylamines and the alkanolamines.
~(~148~
In a particularly preferred modification, the silver addition to the catalyst support is rnade by techniques such as those disclosed in U.S.Patent Specification 3,702,259. This preferred preparation method involves impregnation of an alumina support with certain aqueous silver salt solutions and a subsequent thermal reduction of the silver salt. The silver impregnation solution consists essentially of:
A.a silver salt of a carboxylic acid, B. an organic amine alkaline solubilizing/reducing agent, and C. an additional aqueous solvent as is required to achieve the desired silver level.
Suitable carboxylic acid silver salts include silver carbonate and the silver salts of mono- and polybasic carboxylic and hydroxycarboxylic acids of up to about 16 carbon atoms per molecule. Silver carbonate and silver oxalate are particularly useful silver salts, with silver oxalate being most preferred.
An organic amine solubilizing/reducing agent is present in the impregnating solution used in this prepration method. Suitable organic amine silver-solubilizing/reducing agents include lower alkylenediamines of from 1 to 5 carbon atoms per molecule, mixtures of a lower alkanolamine of from 1 to 5 carbon atoms with a lower alkylenediamine of from 1 to 5 carbon atoms, as well as mixtures of ~0480~(~
ammonia with lower alkanolamines or lower alkylene-diamines of from 1 to 5 carbons. Four groups of organic amine solubilizing/reducing agents are preferred. They are the following:
A. vicinal alkylenediamines of from 2 to 4 carbon atoms, B. mixtures of (1) vicinal alkanolamines of from 2 to 4;carbon atoms and (2) vicinal alkylenediamines of from 2 to 4 carbon atoms;
C. mixtures of vicinal alkylenediamines of from 2 to 4 carbon atoms and ammonia; and D. mixtures of vicinal alkanolamines of from 2 to
4 carbon atoms and ammonia.
These preferred solubilizing/reducing agents are generally added in the amount of from 0.1 to 10 moles per mole of silver present.
~ ery preferred as solubilizing/reducing agents are:
A. ethylenediamine, . ethylenediamine in combination with ethanolamine, C. ethylenediamine in combination with ammonia and D. ethanolamine in combination with ammonia.
Ethylenediamine, alone or in combination with ethanolamine, is most preferred.
When ethy]enediamine is used as the sole solubilizlng/r~luci~g agent, it is necessary to add amounts of the amine in the range of from 0.1 to 5.0 moles of ethylenediamine per mole of silver.
When ethylenediamine and ethanolamine together are used as solubllizing/reducing agent, it is suitable to employ from 0 1 to 3.0 moles of ethylenediamine per mole of silver and from 0.1 to 2.0 moles of ethanolamine per mole of silver.
When ethylenediamine or ethanolamine is used with ammonia, it is generally useful to add at least about two moles of ammonia per mole of silver and very suitable to add from about 2 to about 10 moles of ammonia per mole of silver. The amount of ethylenediamine or ethanolamine employed is suitably from 0.1 to 2.0 moles per mole of silver.
As already noted, it is essential that only certain controlled amounts of the hi~her alkali metals of the invention be present, these amounts being a function of the surface area of the catalyst support. These amounts are achieved by either controlled addition of alkali metal to the support in the first impregnation step or by controlled removal of excess alkali metal from the impregnated catalyst support either before or after the silver impregnation step.
The thermal treatment of step (d) may be carried out at a temperature of from 100 to 500C, preferably to 375C, and more preferably from 125 to 325C, for the time, typically 0.5 to 8 hours, required to decompose ~L~348~:~0 the silver salt and form the adherent particulate deposit of metallic silver o~ the surfaces. Lower temperatures do not adequately decompose the silver salt and ~hould be avoided. More than one temperature may be employed.
The higher alkali metal-promoted silver catalysts have been shown to be particularly selective catalysts in the direct oxidation of ethylene with molecular oxygen to ethylene oxide. The conditions for carrying out such an oxidation reaction in the presence of the silver catalysts of the present invention broadly comprise those described in the prior art. This applies, for example, to suitable temperatures, pressures, residence times, diluent materials such as nitrogen, carbon dioxide, steam, argon, methane or other saturated hydrocarbons, the presence or absence of moderating agents to control the catalytic action, for example 1,2-dichloroethane, vinyl chloride or chlorinated polyphenyl compounds, the desirability of employing recycle operations or applying successive conversions in different reactors to increase the yields of ethylene oxide, and any other special conditions which may be selected in processes - for preparing ethylene oxide. Pressures in the range of from about atmospheric to about 35 bar abs. are generally employed. Higher pressures may, however, be emplyed within the scope of the invention. Molecular oxygen employed as reactant is obtained from conventional sources. The suitable oxygen charge may consist essentially :`
~o~
of relatively pure oxygenl a concentrated oxygen stream comprising oxygen in major amounts with lesser amounts of one or more diluents, such as nitrogen, argon, etc., or another oxygen-containing stream, such as air. The use of the present novcl silver catalysts in ethylene oxidation reactions is in no way limited to the use of specific conditions among those which are known to be effective.
In a preferred application of the silver catalysts of the invention ethylene oxide is produced when an oxygen-containing gas of not less than 95% oxygen is contacted with ethylene in the presence of the present catalysts at a temperature in the range of from 210C to 285C and preferably 225C to 270C. Accordingly, the present invention also provides a process for the production of ethylene oxide by direct oxidation of ethylene in the vapour phase with molecular oxygen at ethylene oxide forming conditions at a temperature in the range from 210C to 285C in the presence of a fixed bed of a silver catalyst, which process is conducted in the presence of a silver catalyst as previously described.
The resulting ethylene oxide is separated and recovered from the reaction products by conventional methods known and used in the art. Use of the silver catalysts of the invention in ethylene oxide production processes gives higher overall ethylene oxidation selectivities to ethylene oxide at a given ethylene conversion than is possible with conventional ca~alysts.
While the reason for these higher selectivities observed with catalysts of this invention is not fully understood, experiments have indicated that conventional silver catalysts ~not containing higher alkali metals) cause ethylene oxide to combust after formation while silver catalysts containing higher alkali metals according to this invention do not cause as extensive ethylene oxide comhustion.
,~' - 21 - ~4~
The invention is ~urther illustrated by means of the ~ollowing Examples.
EXAMPLE I
~_ . .
A series of catalysts were prepared using alumina supports with different surface areas. The physical properties o~ these supports are shown in table I.
~4~ 0 Table I
Catalyst support A B C D E
Trade name -Carborun- Norton Girdler Péchiney dum Company SRS 6 Sur~ace area, m2g 0.19 0.51 1.07 1.32 6.55 Form of particles rings spheres, cylin- rings, spheres, 8 mm diam. 5 mm ders,diam. diam. diam.2 to
These preferred solubilizing/reducing agents are generally added in the amount of from 0.1 to 10 moles per mole of silver present.
~ ery preferred as solubilizing/reducing agents are:
A. ethylenediamine, . ethylenediamine in combination with ethanolamine, C. ethylenediamine in combination with ammonia and D. ethanolamine in combination with ammonia.
Ethylenediamine, alone or in combination with ethanolamine, is most preferred.
When ethy]enediamine is used as the sole solubilizlng/r~luci~g agent, it is necessary to add amounts of the amine in the range of from 0.1 to 5.0 moles of ethylenediamine per mole of silver.
When ethylenediamine and ethanolamine together are used as solubllizing/reducing agent, it is suitable to employ from 0 1 to 3.0 moles of ethylenediamine per mole of silver and from 0.1 to 2.0 moles of ethanolamine per mole of silver.
When ethylenediamine or ethanolamine is used with ammonia, it is generally useful to add at least about two moles of ammonia per mole of silver and very suitable to add from about 2 to about 10 moles of ammonia per mole of silver. The amount of ethylenediamine or ethanolamine employed is suitably from 0.1 to 2.0 moles per mole of silver.
As already noted, it is essential that only certain controlled amounts of the hi~her alkali metals of the invention be present, these amounts being a function of the surface area of the catalyst support. These amounts are achieved by either controlled addition of alkali metal to the support in the first impregnation step or by controlled removal of excess alkali metal from the impregnated catalyst support either before or after the silver impregnation step.
The thermal treatment of step (d) may be carried out at a temperature of from 100 to 500C, preferably to 375C, and more preferably from 125 to 325C, for the time, typically 0.5 to 8 hours, required to decompose ~L~348~:~0 the silver salt and form the adherent particulate deposit of metallic silver o~ the surfaces. Lower temperatures do not adequately decompose the silver salt and ~hould be avoided. More than one temperature may be employed.
The higher alkali metal-promoted silver catalysts have been shown to be particularly selective catalysts in the direct oxidation of ethylene with molecular oxygen to ethylene oxide. The conditions for carrying out such an oxidation reaction in the presence of the silver catalysts of the present invention broadly comprise those described in the prior art. This applies, for example, to suitable temperatures, pressures, residence times, diluent materials such as nitrogen, carbon dioxide, steam, argon, methane or other saturated hydrocarbons, the presence or absence of moderating agents to control the catalytic action, for example 1,2-dichloroethane, vinyl chloride or chlorinated polyphenyl compounds, the desirability of employing recycle operations or applying successive conversions in different reactors to increase the yields of ethylene oxide, and any other special conditions which may be selected in processes - for preparing ethylene oxide. Pressures in the range of from about atmospheric to about 35 bar abs. are generally employed. Higher pressures may, however, be emplyed within the scope of the invention. Molecular oxygen employed as reactant is obtained from conventional sources. The suitable oxygen charge may consist essentially :`
~o~
of relatively pure oxygenl a concentrated oxygen stream comprising oxygen in major amounts with lesser amounts of one or more diluents, such as nitrogen, argon, etc., or another oxygen-containing stream, such as air. The use of the present novcl silver catalysts in ethylene oxidation reactions is in no way limited to the use of specific conditions among those which are known to be effective.
In a preferred application of the silver catalysts of the invention ethylene oxide is produced when an oxygen-containing gas of not less than 95% oxygen is contacted with ethylene in the presence of the present catalysts at a temperature in the range of from 210C to 285C and preferably 225C to 270C. Accordingly, the present invention also provides a process for the production of ethylene oxide by direct oxidation of ethylene in the vapour phase with molecular oxygen at ethylene oxide forming conditions at a temperature in the range from 210C to 285C in the presence of a fixed bed of a silver catalyst, which process is conducted in the presence of a silver catalyst as previously described.
The resulting ethylene oxide is separated and recovered from the reaction products by conventional methods known and used in the art. Use of the silver catalysts of the invention in ethylene oxide production processes gives higher overall ethylene oxidation selectivities to ethylene oxide at a given ethylene conversion than is possible with conventional ca~alysts.
While the reason for these higher selectivities observed with catalysts of this invention is not fully understood, experiments have indicated that conventional silver catalysts ~not containing higher alkali metals) cause ethylene oxide to combust after formation while silver catalysts containing higher alkali metals according to this invention do not cause as extensive ethylene oxide comhustion.
,~' - 21 - ~4~
The invention is ~urther illustrated by means of the ~ollowing Examples.
EXAMPLE I
~_ . .
A series of catalysts were prepared using alumina supports with different surface areas. The physical properties o~ these supports are shown in table I.
~4~ 0 Table I
Catalyst support A B C D E
Trade name -Carborun- Norton Girdler Péchiney dum Company SRS 6 Sur~ace area, m2g 0.19 0.51 1.07 1.32 6.55 Form of particles rings spheres, cylin- rings, spheres, 8 mm diam. 5 mm ders,diam. diam. diam.2 to
5 mm 15 mm 5 mm Sodium content,%w 0.02 0.13 0.24 o.40 0.52 Zinc content, %w - - 0.24 0. 23 Silica content,%w 0. 26 2.37 0.15 0.28 2.5 Iron content, %w 0.09 0.45 o.o4 0.03 0.05 Trace metals other than Na, Zn, Si and Fe, %w oxides 0.33 0.85 0.25 0.3 0.3 Apparent porosity~),%v 24 50 25 25 40 Median pore diameter, micron 3.9 2 o.8 0.6 0.25 80% of the pores had diameters in the range of from .. to .. ~micron 1.5-15 0.3-10 0.4-1.2 0.2-1.5 0.1-0.9 Pore volume"),ml/g0.23 0.25 0.22 0.45 _______ ') from water adsorption ~') determined by means of the mercury porosimeter 2~ 480~L0 C fl ti fl ly r~ ti F~ d rl lJ ~ n a li (3 (~ A ~ 1., /~ - 2, .... ~ J., r3 t; c .
Wr.)r~ marl~3 'Lrl aC'COrdflrlCe Wl.t;tl t~l:i.f3 invr?nti:lon~ that if~, h ,y t h e c3 ~ n ~, .l. fl :1 cl r? l~ r.) [~; :l. t, i c) ~ o L~ t, f l ~,' .a :l. k f~ i rnc ti a l. a nd tihr,~ ~I.l3.vr.?r. C'flt;l'l.y).~ rlc!fJ.i p;rlr.ll;ed M/\-O, f;~l3-0, . . ., ~ ~0, r3t;c, wrlrr3 n~t :Ln acc,c)rclfln~le w:i.t;h th(? :invr~nt;ir.?-n ln that th~?y cont;fl.:i.n~d no alka:l i rnet,f~ a.tia3yf3t,f^~ c1r~F;.i~nati~d N~ M~\-2, . . . ) Nl.~-'l, rnkc~ wt~re~ f.;l~.f~;O not; :I.n accordanc w.lt;h th;l.)i,; .lnvf~nt:ioll in that t,h~J d~pof~lt.lorl o-f' thre alka:L
m~3t~.1 an(l ti^lr.~ Fsl,`l.vc.~r~ w~!:rr~ marlr.,~ r3Lmult,anc!c)uf.~ Ly.
J,O '.L'o L'lLul~.;krak,f? thr~ prr?r~flrflt,:lon o~ crlt,lll$rFitf.~ in ~coorclflnc~ w.l. kh th.lf~ Invr.?nl;lon th~ pr~paratii.on o.f catalyst~
rna~ wl~h ~upport C .1~ El~`ti out; he:low. rrhe other catalyf3t~
:ln accorfl~n~o wllih thf3 Inv~?nl~ion w~,rf~ prc!p~lred ln a a lm.l la:r ~fJh:l orl .
~1'3 An amc)unti o;f` 30 ~; ot` ~mppo:rk C h~vLn~, a ~ur.~ac~
~r~Q o~ L . 07 m /~, wQr~ .f~;ir~3t :imprf?~n~t;f?~ un~lf~?r a prf~?ssurf~
o~E` O . 04 ba.r ab~ . .In a rot~ry ~vapo:r ator wi th ~ . 5 ml o.~ an acluf~oufl ~30:luki:Lon c,~ontaln Inp 3 m~ ce~,.iunl hyclroxide p~x~ ml ~lo~ t:lon, '.['h~ :i.mpre~n~ll;t~(.l sl~pport wa~ clr:1~d 2t~ by h~lt~tlp~ ror 3t) m:i.tl ak :llQC, and kh~n Ior tiwo hour~t at ~50C .ln ~1 ~.ttre~lm ol` n:i t;ro~;en.
~]~ 1UppOrti W~1~3 th~n .impr~ .rnat~cl w:i ~h an aclueou~3 ~tolutlon o.~` ~tl.~ltrer ~ rrh:lS ~C)lUkiOtl wa't prep~recl by the ro'1lowit~ t~ohr~ u~. 6 Qram~3 anhy(lrou~t sllv~r ~5 n:l~.r~t~ nnd 3.3 gr~ s pc~t~3~.nLllm ox~lat~,e (K~C204.1 ~120) w~r~ ~p~rat~ly ct.l.ssolv~?d i.n ClUf~l'lt:itt:i~?S Or l~Q ml of w~t~.r~ ~rt~ 30 ~ ob~ d W(?~ m:i~x(?d ~ d h~ .t~d 24 ~
on a steam bath. The silver oxalate precipitate was centrifuged and the supernata~t liquid decanted. Subsequently, the precipitate was washed five times with 100 ml hot (60-9oC) distilled water. The precipitate was centrifuged and the water decanted after each washing. The precipitate was then dissolved in 10 ml of a mixture consisting of 75 %v of 1,2-diaminoethane and 25 %v of waterg the mixture being cooled in ice. A quantity of 30 grams of the cesium-containing support was then consecutively impregnated at a pressure of 0.04 bar abs. in a rotary evaporator, with 8.5 ml of the latter liquid, warmed up by indirect heat exchange with hot water to a temperature of 60C with rotation, again at 0.04 bar abs, to partially remove the solvent, poured out onto a large filter paper and gently shaken to remove any excess moisture, heated in a stream of nitrogen for a period of two hours until a temperature of 300C was attained and kept at 300C for a further two hours. The catalyst was then cooled to ambient temperature. The silver content of the catalyst was 7.8 % by weight. The cesium content amounted to 3.35 mgew per kg catalyst. Examination of the catalyst with an electron microscope revealed that the silver had been deposited on the support as discrete particles with a uniform diameter of from 5 to 0.3 microns (500 to 3000 A). The silver particles were uniformly spaced over the surface of the ~upport.
4~1~9 0 To prepare the NA-0, ..., NI-O series of catalysts which did not contain any alkali metal, the first impregnation step with the cesium hydroxide solution described above was omitted with the subsequent steps being substantially the same.
To prepare the NA-1, NA-2, ..., N~-5, series of catalysts not in accordance with the invention, the first impregnation step with the cesium hydroxide described above was also omitted. The subsequent steps were followed in a substantially similar fashion with the exception that cesium hydroxide was added to the silver ethylenediamine-water solution in su~ficient quantities to provide the desired alkali metal content in the final catalyst product.
The catalysts prepared above were comparatively tested for the production of ethylene oxide. The reactor consisted of a tube with an internal diameter of 5 mm and was in each experiment rilled over a length of 12 cm with catalyst particles whose dimensions were in the range between 0.4 and o.8 mm. These catalyst particles were obtained by crushing the catalyst particles prepared as described in the above.
A mixture containing oxygen and ethylene was conducted through the catalyst bed in the presence of a small amount of vinyl chloride as a moderator under the following conditions:
~L~4801(~
Pressure ~ . . . . . . . . . . . . . . . . . . . 14.5 bar abs space velocity . . . . . . . . . . . . . . . . .3300 h 1 ethylene in feed ............................. 30 %m oxygen in feed . . . . . . . . . . . . . . . . . 8.5 ~m nitrogen in feed . . . . . . . . . . . . . . . . 61.5 %m moderator concentration, parts of vinyl chloride per million parts of feed (vol). . . . . . . . . 10 ppm The reaction temperature was adjusted to provide for an oxygen conversion of 52% and the selectivity to ethylene oxide was determined. The selectivity to ethylene oxide~ expressed as a percentage, is defined as the number of moles of ethylene oxide formed out of 100 moles converted ethylene. The results of the above described experiments are shown in Tables II
through VI. As can be noted from these tables, at the lowest support surface areas used, the sequential deposition method of this invention give similar results to the simultaneous deposition method. However, with the more desirable hi~her surface area supports, the technique of this invention produces far superior catalyst to those not produced in accordance with this invention.
.
.~ - 27 -109~81~10 Table II
Catalyst prepared with supports having surface areas of 0.19 m /g Cat. Silver Cesium content Reactor Oxidation content mgew7kg ppmw temp to selectivity to achieve ethylene 52% O oxide, %
conve~-_____ _~______ ________ _________ _ionlC
A-1') 7.0 0.86 114 259 79.9 A-2 7.6 1.01 134 255 80 3 A-3 7.9 1.11 148 259 80.7 A-4 7.6 1.49 198 265 79.8 A-5 8.2 1.65 220 261 79.0 NA-O 7.8 0 0 - 251 69.5 NA-1 8.3 0.77.103 254 80.3 NA-2 8.3 1.08 143 258 80 6 NA-3 7.7 1,25 166 263 80.2 NA-4 7.8 1.64 218 264 79 7 NA-5 8.o 1 89 252 295 76.1 ======--==================================
A-1. A-2,..., B-1, etc, are catalysts prepared according to this invention.
NA-O, NB~O, etc, are catalysts not according to this invention and with no alkali metal additionO
NA-1, NA-2,... , NB 1, etc, are catalysts not according to this invention and prepared by the simultaneous deposition of alkali metal with the silver.
- 2~ - ~
Table III
Catalyst prepared with supports having sur~ace areas o~ 0.51 m /g.
Catalyst Silver Cesium_content Reactor Oxidation Content mgew7kg ppmw temp.to selectivity to achieve to ethylene 52% O~ oxide,%
conve -__ ____ _______ ________ ________ _ion~C
B-1~) 7.7 o.89118 254 74.5 B-2 7.9 1.53204 252 77.8 B-3 7.7 2.79371 258 78.2 B-4 7.5 3.77502 259 76.5 B-5 7.9 5.50732 , 300 70.4 NB-O 7.7 0 0 251 71.0 NB-1 7.1 2.64351 261 77.6 NB-2 7.4l 3.78503 274 76.1 NB-3 8~0 5.47728 > 300 64 ====_==_=================================================_======
7) See footnote ~) of Table II.
- 29 - ~ ~4~0 Table IV
Catalyst prepared with supports having sur~ace areas of I.07 m2/~
Catalyst Silver Cesium content Reactor Oxidation content mgew7kg ppmw temp.to selectivity to achieve ethylene 52% O oxide, %
conve~-sion,C
.______.__ ________ . ______________ C-1")8,4 1,56 208 237 77.7 C-2 8.83.52 468 249 78,4 C-3 10,7 6,o3 802 255 79.5 C-4 8,76.59 877 256 77.5 C-5 10,6 7.95 1058 268 76,4 NC-O 8,o 0 0 260 71,9 NC-1 8,o 1,87 249 251 75,1 NC-2 8,o 3.11 430 260 75,9 NC-3 8,4 4,08 543 252 76.2 NC-4 9,2 4,80 639 257 74.7 NC-5 8.o 5.43 722 320 67.8 ================================_=====================.
') See footnote of table II.
, .~
~04813~
Table V
Catalyst Prepared with Supports having surface are,as of 1.32 m2/g Catalyst Silver Cesium content Reactor Oxidation content mgew7kg ppmw temp.to selectivity to achieve ethylene 52% O oxide,%
conve~-,________ _______ ________ ________ __onl_C__ ____.____ _____ D-1l) 6.6 4.19 557 260 67.0 D-2 6.o 6.35 844 265 73.2 D-3 6.9 7.691024 264 75.4 D-4 7.2 9.561272 261 74.3 ND-0 5.4 0 0 257 66.o ND-1 5.4 4. o8543 ' 293 65.6 ND-2 5O4 4.69 624 289 63.2 =_====_======================================================._=
~) See footnote ~) of table II
Table VI
Catalyst prepared with supports having surface areas of 6.~55 m2/g Catalyst Silver Cesium content Reactor Oxidation content mgew7kg ppmw temp.to selectivity to achieve ethylene 52% O~ oxide,%
conve~-__ ____ ________ _______ ___ _ sion~C
E-17) 11.5 25.73420 207 73~3 E-2 11.0 35.34690 205 75,4 E-3 11,2 39.55250 205 75.1 NE-0 9.4 0 0 220 50.0 NE-1 11.9 42.35621 277 42.4 =====================_=========================================
') See footnote') Or table II.
- 31 ~
The above~mentioned results are also represented in the accompanying graph, where the cesium contents ; of the catalysts, in ppm, are plotted along the horizontal axis and the selectivities to ethylene oxide, in %, 5 along the vertical axis. The selectivities of the catalysts made from the five different aluminas mentioned in Table I are indicated in the graph with five different ; symbols. The five lines based on each set of symbols represent the selectivity as a function of the cesium content for the surface area stated near each line.
The four lines for the surface areas 0.19, 0.51, 1.07 and 1. 32 m /g are based on the left hand and lower scales, whereas the line for the surface area 6.55 m /g is based on the left hand and upper scales. The vertical arrows pointed to each of the five curves indicate the optimum cesium content of each of the four catalysts. These optimum cesium contents are stated in Table VII.
Table VII
Alumina surface Optimum cesium Selectivity at Optimum cesium area, m2/g content, mgew/ optimum cesium content divided kg content, % by surface a~ea ________________ ______________ ______________ (mg_w!kg)/(m /g~
0.19 1.12 80.7 5.9 0.51 2.26 78.4 4.5 1.07 6.02 79.5 5.6 1.32 8.13 75.5 6.1
Wr.)r~ marl~3 'Lrl aC'COrdflrlCe Wl.t;tl t~l:i.f3 invr?nti:lon~ that if~, h ,y t h e c3 ~ n ~, .l. fl :1 cl r? l~ r.) [~; :l. t, i c) ~ o L~ t, f l ~,' .a :l. k f~ i rnc ti a l. a nd tihr,~ ~I.l3.vr.?r. C'flt;l'l.y).~ rlc!fJ.i p;rlr.ll;ed M/\-O, f;~l3-0, . . ., ~ ~0, r3t;c, wrlrr3 n~t :Ln acc,c)rclfln~le w:i.t;h th(? :invr~nt;ir.?-n ln that th~?y cont;fl.:i.n~d no alka:l i rnet,f~ a.tia3yf3t,f^~ c1r~F;.i~nati~d N~ M~\-2, . . . ) Nl.~-'l, rnkc~ wt~re~ f.;l~.f~;O not; :I.n accordanc w.lt;h th;l.)i,; .lnvf~nt:ioll in that t,h~J d~pof~lt.lorl o-f' thre alka:L
m~3t~.1 an(l ti^lr.~ Fsl,`l.vc.~r~ w~!:rr~ marlr.,~ r3Lmult,anc!c)uf.~ Ly.
J,O '.L'o L'lLul~.;krak,f? thr~ prr?r~flrflt,:lon o~ crlt,lll$rFitf.~ in ~coorclflnc~ w.l. kh th.lf~ Invr.?nl;lon th~ pr~paratii.on o.f catalyst~
rna~ wl~h ~upport C .1~ El~`ti out; he:low. rrhe other catalyf3t~
:ln accorfl~n~o wllih thf3 Inv~?nl~ion w~,rf~ prc!p~lred ln a a lm.l la:r ~fJh:l orl .
~1'3 An amc)unti o;f` 30 ~; ot` ~mppo:rk C h~vLn~, a ~ur.~ac~
~r~Q o~ L . 07 m /~, wQr~ .f~;ir~3t :imprf?~n~t;f?~ un~lf~?r a prf~?ssurf~
o~E` O . 04 ba.r ab~ . .In a rot~ry ~vapo:r ator wi th ~ . 5 ml o.~ an acluf~oufl ~30:luki:Lon c,~ontaln Inp 3 m~ ce~,.iunl hyclroxide p~x~ ml ~lo~ t:lon, '.['h~ :i.mpre~n~ll;t~(.l sl~pport wa~ clr:1~d 2t~ by h~lt~tlp~ ror 3t) m:i.tl ak :llQC, and kh~n Ior tiwo hour~t at ~50C .ln ~1 ~.ttre~lm ol` n:i t;ro~;en.
~]~ 1UppOrti W~1~3 th~n .impr~ .rnat~cl w:i ~h an aclueou~3 ~tolutlon o.~` ~tl.~ltrer ~ rrh:lS ~C)lUkiOtl wa't prep~recl by the ro'1lowit~ t~ohr~ u~. 6 Qram~3 anhy(lrou~t sllv~r ~5 n:l~.r~t~ nnd 3.3 gr~ s pc~t~3~.nLllm ox~lat~,e (K~C204.1 ~120) w~r~ ~p~rat~ly ct.l.ssolv~?d i.n ClUf~l'lt:itt:i~?S Or l~Q ml of w~t~.r~ ~rt~ 30 ~ ob~ d W(?~ m:i~x(?d ~ d h~ .t~d 24 ~
on a steam bath. The silver oxalate precipitate was centrifuged and the supernata~t liquid decanted. Subsequently, the precipitate was washed five times with 100 ml hot (60-9oC) distilled water. The precipitate was centrifuged and the water decanted after each washing. The precipitate was then dissolved in 10 ml of a mixture consisting of 75 %v of 1,2-diaminoethane and 25 %v of waterg the mixture being cooled in ice. A quantity of 30 grams of the cesium-containing support was then consecutively impregnated at a pressure of 0.04 bar abs. in a rotary evaporator, with 8.5 ml of the latter liquid, warmed up by indirect heat exchange with hot water to a temperature of 60C with rotation, again at 0.04 bar abs, to partially remove the solvent, poured out onto a large filter paper and gently shaken to remove any excess moisture, heated in a stream of nitrogen for a period of two hours until a temperature of 300C was attained and kept at 300C for a further two hours. The catalyst was then cooled to ambient temperature. The silver content of the catalyst was 7.8 % by weight. The cesium content amounted to 3.35 mgew per kg catalyst. Examination of the catalyst with an electron microscope revealed that the silver had been deposited on the support as discrete particles with a uniform diameter of from 5 to 0.3 microns (500 to 3000 A). The silver particles were uniformly spaced over the surface of the ~upport.
4~1~9 0 To prepare the NA-0, ..., NI-O series of catalysts which did not contain any alkali metal, the first impregnation step with the cesium hydroxide solution described above was omitted with the subsequent steps being substantially the same.
To prepare the NA-1, NA-2, ..., N~-5, series of catalysts not in accordance with the invention, the first impregnation step with the cesium hydroxide described above was also omitted. The subsequent steps were followed in a substantially similar fashion with the exception that cesium hydroxide was added to the silver ethylenediamine-water solution in su~ficient quantities to provide the desired alkali metal content in the final catalyst product.
The catalysts prepared above were comparatively tested for the production of ethylene oxide. The reactor consisted of a tube with an internal diameter of 5 mm and was in each experiment rilled over a length of 12 cm with catalyst particles whose dimensions were in the range between 0.4 and o.8 mm. These catalyst particles were obtained by crushing the catalyst particles prepared as described in the above.
A mixture containing oxygen and ethylene was conducted through the catalyst bed in the presence of a small amount of vinyl chloride as a moderator under the following conditions:
~L~4801(~
Pressure ~ . . . . . . . . . . . . . . . . . . . 14.5 bar abs space velocity . . . . . . . . . . . . . . . . .3300 h 1 ethylene in feed ............................. 30 %m oxygen in feed . . . . . . . . . . . . . . . . . 8.5 ~m nitrogen in feed . . . . . . . . . . . . . . . . 61.5 %m moderator concentration, parts of vinyl chloride per million parts of feed (vol). . . . . . . . . 10 ppm The reaction temperature was adjusted to provide for an oxygen conversion of 52% and the selectivity to ethylene oxide was determined. The selectivity to ethylene oxide~ expressed as a percentage, is defined as the number of moles of ethylene oxide formed out of 100 moles converted ethylene. The results of the above described experiments are shown in Tables II
through VI. As can be noted from these tables, at the lowest support surface areas used, the sequential deposition method of this invention give similar results to the simultaneous deposition method. However, with the more desirable hi~her surface area supports, the technique of this invention produces far superior catalyst to those not produced in accordance with this invention.
.
.~ - 27 -109~81~10 Table II
Catalyst prepared with supports having surface areas of 0.19 m /g Cat. Silver Cesium content Reactor Oxidation content mgew7kg ppmw temp to selectivity to achieve ethylene 52% O oxide, %
conve~-_____ _~______ ________ _________ _ionlC
A-1') 7.0 0.86 114 259 79.9 A-2 7.6 1.01 134 255 80 3 A-3 7.9 1.11 148 259 80.7 A-4 7.6 1.49 198 265 79.8 A-5 8.2 1.65 220 261 79.0 NA-O 7.8 0 0 - 251 69.5 NA-1 8.3 0.77.103 254 80.3 NA-2 8.3 1.08 143 258 80 6 NA-3 7.7 1,25 166 263 80.2 NA-4 7.8 1.64 218 264 79 7 NA-5 8.o 1 89 252 295 76.1 ======--==================================
A-1. A-2,..., B-1, etc, are catalysts prepared according to this invention.
NA-O, NB~O, etc, are catalysts not according to this invention and with no alkali metal additionO
NA-1, NA-2,... , NB 1, etc, are catalysts not according to this invention and prepared by the simultaneous deposition of alkali metal with the silver.
- 2~ - ~
Table III
Catalyst prepared with supports having sur~ace areas o~ 0.51 m /g.
Catalyst Silver Cesium_content Reactor Oxidation Content mgew7kg ppmw temp.to selectivity to achieve to ethylene 52% O~ oxide,%
conve -__ ____ _______ ________ ________ _ion~C
B-1~) 7.7 o.89118 254 74.5 B-2 7.9 1.53204 252 77.8 B-3 7.7 2.79371 258 78.2 B-4 7.5 3.77502 259 76.5 B-5 7.9 5.50732 , 300 70.4 NB-O 7.7 0 0 251 71.0 NB-1 7.1 2.64351 261 77.6 NB-2 7.4l 3.78503 274 76.1 NB-3 8~0 5.47728 > 300 64 ====_==_=================================================_======
7) See footnote ~) of Table II.
- 29 - ~ ~4~0 Table IV
Catalyst prepared with supports having sur~ace areas of I.07 m2/~
Catalyst Silver Cesium content Reactor Oxidation content mgew7kg ppmw temp.to selectivity to achieve ethylene 52% O oxide, %
conve~-sion,C
.______.__ ________ . ______________ C-1")8,4 1,56 208 237 77.7 C-2 8.83.52 468 249 78,4 C-3 10,7 6,o3 802 255 79.5 C-4 8,76.59 877 256 77.5 C-5 10,6 7.95 1058 268 76,4 NC-O 8,o 0 0 260 71,9 NC-1 8,o 1,87 249 251 75,1 NC-2 8,o 3.11 430 260 75,9 NC-3 8,4 4,08 543 252 76.2 NC-4 9,2 4,80 639 257 74.7 NC-5 8.o 5.43 722 320 67.8 ================================_=====================.
') See footnote of table II.
, .~
~04813~
Table V
Catalyst Prepared with Supports having surface are,as of 1.32 m2/g Catalyst Silver Cesium content Reactor Oxidation content mgew7kg ppmw temp.to selectivity to achieve ethylene 52% O oxide,%
conve~-,________ _______ ________ ________ __onl_C__ ____.____ _____ D-1l) 6.6 4.19 557 260 67.0 D-2 6.o 6.35 844 265 73.2 D-3 6.9 7.691024 264 75.4 D-4 7.2 9.561272 261 74.3 ND-0 5.4 0 0 257 66.o ND-1 5.4 4. o8543 ' 293 65.6 ND-2 5O4 4.69 624 289 63.2 =_====_======================================================._=
~) See footnote ~) of table II
Table VI
Catalyst prepared with supports having surface areas of 6.~55 m2/g Catalyst Silver Cesium content Reactor Oxidation content mgew7kg ppmw temp.to selectivity to achieve ethylene 52% O~ oxide,%
conve~-__ ____ ________ _______ ___ _ sion~C
E-17) 11.5 25.73420 207 73~3 E-2 11.0 35.34690 205 75,4 E-3 11,2 39.55250 205 75.1 NE-0 9.4 0 0 220 50.0 NE-1 11.9 42.35621 277 42.4 =====================_=========================================
') See footnote') Or table II.
- 31 ~
The above~mentioned results are also represented in the accompanying graph, where the cesium contents ; of the catalysts, in ppm, are plotted along the horizontal axis and the selectivities to ethylene oxide, in %, 5 along the vertical axis. The selectivities of the catalysts made from the five different aluminas mentioned in Table I are indicated in the graph with five different ; symbols. The five lines based on each set of symbols represent the selectivity as a function of the cesium content for the surface area stated near each line.
The four lines for the surface areas 0.19, 0.51, 1.07 and 1. 32 m /g are based on the left hand and lower scales, whereas the line for the surface area 6.55 m /g is based on the left hand and upper scales. The vertical arrows pointed to each of the five curves indicate the optimum cesium content of each of the four catalysts. These optimum cesium contents are stated in Table VII.
Table VII
Alumina surface Optimum cesium Selectivity at Optimum cesium area, m2/g content, mgew/ optimum cesium content divided kg content, % by surface a~ea ________________ ______________ ______________ (mg_w!kg)/(m /g~
0.19 1.12 80.7 5.9 0.51 2.26 78.4 4.5 1.07 6.02 79.5 5.6 1.32 8.13 75.5 6.1
6.55 35.7 75.4 5.4 =_======== = ======================================================
- 32 - ~0480~
EXAMPLE II
Catalysts in accordance with this invention containing varying amounts of potassium as the higher alkali metal component were prepared using the feedstocks and general preparative t;echniques c-f Example I. Instead of adding cesium to the first impregnating solution, potassium as potassium hydroxide was added. The catalyst compositions, so prepared, were tested as ethylene oxide catalysts using the apparatus and technique of Example I. The compositions of these catalysts along with the results are given in Table VIII.
Table III
Catalyst prepared with supports having surface areas of 0,19 m /g Catalyst Silver Potassium content Reactor Oxidation content mgew7kg ppmw temp.to selectivity to achieve ethylene 52% O oxide,%
conve~
sion C
________ _______ ______ ________ ____~___ ______________ F-1') 7.8 1.7468 256 79.8 NF-0 7.8 0 _ 251 69.5 ======_=======___==_=====_===_=====_=_===========_==========_==
') See footnote ') of table II.
EXAMPLE III
Catalysts in accordance with this invention cotaining varying amounts of rubidium as the higher alkali metal component were prepared using the feedstocks and general preparative techniques of Example I. Instead of adding cesium hydroxide to the first impregnating solution, ~C~48~1~
rubidium as rubidium hydroxide was added. The catalyst compositions so prepared were tested as ethylene oxide catalyst using the apparatus and technique of Example I.
The compositions of the catalysts along with the results are given in Table IX.
Table IX
Catalyst prepared with supports having surface areas of 0.19 m /g.
Catalyst Silver Rubidium Content Reactor Oxidation content mgew/kg ppmw temp. selectivity to achie- to ethylene ve 52% 2 oxide, %
conver-sion C
__ _____ _______ ______,_ _________ ____~____ ___________ G~1l) 7.8 1.0690 252 76.7 NG-O 7.8 0 0 251 69.5 ========================================================= = .
~) See footnote') of Table II.
EXAMPLE IV
A series of catalysts were prepared in the same manner as described in Example I starting from the supports B, C, D and E listed in Table I, but using cesium nitrate instead of cesium hydroxide. The catalysts A, F, K and P containing no cesium were included in Table X for comparative purposes. The catalysts had the properties stated in Table X. The catalysts prepared were comparatively tested for the production of ethylene oxide in fixed beds. The reactor consisted of a tube with an internal diameter of 5 mm and was in each experiment filled over a length of 16 cm with catalyst particles whose largest dimensions varied between 0.4 and o.8 mm.
- 34 ~ q~4~0 A mixture containing oxygen and ethylene was conducted through the catalyst bed in the presence of a small amount of 1,2-dichloroethane as a moderator under the following conditions:
pressure . , . . , , . . . . . . . . 14.5 bar abs.
space velocity , , . . , , . . . . . 3000 h 1 ethylene in feed . . . . . . . . . . 30 %m oxygen in feed . . . . . . . . . . . 7,8 %m nitrogen in feed . . . . . . . . . . 62.2 %m mode~ator concentration, parts of chlorine per million parts of feed(w) 1.5 ppm . The reaction temperature was adjusted to provide for an oxygen conversion of 40% and the selectivity to ethylene oxide was determined. The values of S40 and T40 thus obtained are presented in Table X, together with the number of run hours elapsed at the moment of determination.
~~ - 35 -Table ~
Exp, Cat. Sur~ace Silver Ceslum diameter S40~ T o~ Run No, area of content,content silver % ~hours a~umina, %w Or cat,, particles, m /g mgat/kg microns _____ _ __ ___ ___ _______ _ ____ _ _________ _____ ____ _____ 1 A 0.51 12,8 0 0,1-0,4 76,3 214 100 2 B 0,51 12,1 0,72 0,05-0.5 78,7 220 95 3 C~) 0.51 9,4 1,07 0,1-0,6 79.o 235 120 4 D') 0.51 11.0 1.24 0,1-0.6 79.0 235 120 E 0.51 9.6 1.30 0.05-0.4 79.0 222*) 65 6 F 1,07 9.7 0 0.1-0.4 75.4 210 40
- 32 - ~0480~
EXAMPLE II
Catalysts in accordance with this invention containing varying amounts of potassium as the higher alkali metal component were prepared using the feedstocks and general preparative t;echniques c-f Example I. Instead of adding cesium to the first impregnating solution, potassium as potassium hydroxide was added. The catalyst compositions, so prepared, were tested as ethylene oxide catalysts using the apparatus and technique of Example I. The compositions of these catalysts along with the results are given in Table VIII.
Table III
Catalyst prepared with supports having surface areas of 0,19 m /g Catalyst Silver Potassium content Reactor Oxidation content mgew7kg ppmw temp.to selectivity to achieve ethylene 52% O oxide,%
conve~
sion C
________ _______ ______ ________ ____~___ ______________ F-1') 7.8 1.7468 256 79.8 NF-0 7.8 0 _ 251 69.5 ======_=======___==_=====_===_=====_=_===========_==========_==
') See footnote ') of table II.
EXAMPLE III
Catalysts in accordance with this invention cotaining varying amounts of rubidium as the higher alkali metal component were prepared using the feedstocks and general preparative techniques of Example I. Instead of adding cesium hydroxide to the first impregnating solution, ~C~48~1~
rubidium as rubidium hydroxide was added. The catalyst compositions so prepared were tested as ethylene oxide catalyst using the apparatus and technique of Example I.
The compositions of the catalysts along with the results are given in Table IX.
Table IX
Catalyst prepared with supports having surface areas of 0.19 m /g.
Catalyst Silver Rubidium Content Reactor Oxidation content mgew/kg ppmw temp. selectivity to achie- to ethylene ve 52% 2 oxide, %
conver-sion C
__ _____ _______ ______,_ _________ ____~____ ___________ G~1l) 7.8 1.0690 252 76.7 NG-O 7.8 0 0 251 69.5 ========================================================= = .
~) See footnote') of Table II.
EXAMPLE IV
A series of catalysts were prepared in the same manner as described in Example I starting from the supports B, C, D and E listed in Table I, but using cesium nitrate instead of cesium hydroxide. The catalysts A, F, K and P containing no cesium were included in Table X for comparative purposes. The catalysts had the properties stated in Table X. The catalysts prepared were comparatively tested for the production of ethylene oxide in fixed beds. The reactor consisted of a tube with an internal diameter of 5 mm and was in each experiment filled over a length of 16 cm with catalyst particles whose largest dimensions varied between 0.4 and o.8 mm.
- 34 ~ q~4~0 A mixture containing oxygen and ethylene was conducted through the catalyst bed in the presence of a small amount of 1,2-dichloroethane as a moderator under the following conditions:
pressure . , . . , , . . . . . . . . 14.5 bar abs.
space velocity , , . . , , . . . . . 3000 h 1 ethylene in feed . . . . . . . . . . 30 %m oxygen in feed . . . . . . . . . . . 7,8 %m nitrogen in feed . . . . . . . . . . 62.2 %m mode~ator concentration, parts of chlorine per million parts of feed(w) 1.5 ppm . The reaction temperature was adjusted to provide for an oxygen conversion of 40% and the selectivity to ethylene oxide was determined. The values of S40 and T40 thus obtained are presented in Table X, together with the number of run hours elapsed at the moment of determination.
~~ - 35 -Table ~
Exp, Cat. Sur~ace Silver Ceslum diameter S40~ T o~ Run No, area of content,content silver % ~hours a~umina, %w Or cat,, particles, m /g mgat/kg microns _____ _ __ ___ ___ _______ _ ____ _ _________ _____ ____ _____ 1 A 0.51 12,8 0 0,1-0,4 76,3 214 100 2 B 0,51 12,1 0,72 0,05-0.5 78,7 220 95 3 C~) 0.51 9,4 1,07 0,1-0,6 79.o 235 120 4 D') 0.51 11.0 1.24 0,1-0.6 79.0 235 120 E 0.51 9.6 1.30 0.05-0.4 79.0 222*) 65 6 F 1,07 9.7 0 0.1-0.4 75.4 210 40
7 G 1.07 8.5 0.32 0,05-0.3 75.9 210 115
8 H 1,07 8.4 C,68 0,1-0.3 76.3 209 117
9 I 1,07 9,0 2.21 0,1-0,4 80,6 209 75 80,5 220 103 79.7 228 260 J 1.07 7.8 3.35 0.05-0.3 79.3 211*) 60 11 K 1,32 8,o 0 0.05-0,2 73,9 205 85 12 L 1,32 9.5 1.07 0.05-0.2 75.6 212 150 13 M 1,32 7,5 2,19 0,05-0,3 76.8 215 145 14 N 1,32 7.8 2,26 0.05-0,3 77,1 208 50 77,5 223 116 77.5 222 215 0 1,32 7.3 2.49 0.05-0.3 77.5 227 167 16 p 6,55 9.4 0 0.05-0.3 50 215 30 17 Q 6.55 8.5 15 0,05-0,3 74,8 200 90 18 R 6.55 8.7 21 0,05-0.2 77,6 191 30 = = = _ = = = = = = = = = = = = = = = = = = _ = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = ~r = =
*) In this case an amount of 3 instead of 1.5 ppm 1,2-dichloroethane was used, temperature corrected to 1.5 ppm from 3 ppm.
') This catalyst was prepared by a single simultaneous impregnation and heated in air at 300C, 3L048~10 s not in acccrdance with the_present invention.
Series A:
.
Catalysts containing varying amounts of lithium, an alkali metal not falling within the scope of this invention, were prepared using the feedstocks and general preparative techniques of Example I. Instead of adding cesium hydroxide to the first impregnating solution, lithium as lithium hydroxide was added. The catalyst compositions so prepared were tested as ethylene oxide catalysts using the apparatus and technique of Example I. The composition of these catalysts along with the results are given in Table XI.
Table XI
Lithium c~talyst prepared with supports having surface areas of 0.19 m /g.
Catalyst Silver Lithium content Reactor Oxidation content mgew7kg ppmw temp. to selectivity to achieve ethylene 52% 0~ oxide, %
conve~sion, C
________ _______ _________ ________________ _______ ______ NH-O') 7.8 0 0 25169.5 NH-l 6.928 200 25073.5 NH-2 6.956 390 25072.4 NH-3 6.972 500 25272.8 ====================_=_==============================_========
') See footnote ') of Table II.
Series B:
Catalysts containing varying amounts of sodi.um, an alkali metal not falling within the scope of this - 37 ~ O
invention were prepared using the feedstocks and general preparative techniques of Example I. Instead o'~ adding cesium hydroxide to the first impregnation solution, sodium as sodium hydroxide was added. The catalyst compositions so prepared were tested as ethylene oxide catalysts using the apparatus techniques o~ example I. The composition of these catalysts along with the results are given in Table XII below.
Table XII
Sodium ca~alyst prepared with supports having surface areas of 0.19 m /g, Catalyst Silver Sodium content_ Reactor Oxidation content mgew7kg ppmw temp. to selectivity to achieve ethylene 52% O oxide, %
conve~sion, ________ _______ ________ ______ ________.. _ ______________ NI-O 7.8 0 0 , 251 69.5 NI-1 7,1 1.22 28 252 72.3 NI-2 7.1 2.17 50 251 74.1 NI-3 7.1 3.22 74 249 75.7 NI-4 7,1 3.57 82 254 75.5 NI-5 7.1 4.39 101 254 75.5 =============_=== ==============================_============
*) In this case an amount of 3 instead of 1.5 ppm 1,2-dichloroethane was used, temperature corrected to 1.5 ppm from 3 ppm.
') This catalyst was prepared by a single simultaneous impregnation and heated in air at 300C, 3L048~10 s not in acccrdance with the_present invention.
Series A:
.
Catalysts containing varying amounts of lithium, an alkali metal not falling within the scope of this invention, were prepared using the feedstocks and general preparative techniques of Example I. Instead of adding cesium hydroxide to the first impregnating solution, lithium as lithium hydroxide was added. The catalyst compositions so prepared were tested as ethylene oxide catalysts using the apparatus and technique of Example I. The composition of these catalysts along with the results are given in Table XI.
Table XI
Lithium c~talyst prepared with supports having surface areas of 0.19 m /g.
Catalyst Silver Lithium content Reactor Oxidation content mgew7kg ppmw temp. to selectivity to achieve ethylene 52% 0~ oxide, %
conve~sion, C
________ _______ _________ ________________ _______ ______ NH-O') 7.8 0 0 25169.5 NH-l 6.928 200 25073.5 NH-2 6.956 390 25072.4 NH-3 6.972 500 25272.8 ====================_=_==============================_========
') See footnote ') of Table II.
Series B:
Catalysts containing varying amounts of sodi.um, an alkali metal not falling within the scope of this - 37 ~ O
invention were prepared using the feedstocks and general preparative techniques of Example I. Instead o'~ adding cesium hydroxide to the first impregnation solution, sodium as sodium hydroxide was added. The catalyst compositions so prepared were tested as ethylene oxide catalysts using the apparatus techniques o~ example I. The composition of these catalysts along with the results are given in Table XII below.
Table XII
Sodium ca~alyst prepared with supports having surface areas of 0.19 m /g, Catalyst Silver Sodium content_ Reactor Oxidation content mgew7kg ppmw temp. to selectivity to achieve ethylene 52% O oxide, %
conve~sion, ________ _______ ________ ______ ________.. _ ______________ NI-O 7.8 0 0 , 251 69.5 NI-1 7,1 1.22 28 252 72.3 NI-2 7.1 2.17 50 251 74.1 NI-3 7.1 3.22 74 249 75.7 NI-4 7,1 3.57 82 254 75.5 NI-5 7.1 4.39 101 254 75.5 =============_=== ==============================_============
Claims (29)
1. Silver catalysts for the production of ethylene oxide comprising silver and one or more alkali compounds on a porous refractory support, which catalysts have been prepared by a process comprising the following steps:
(a) impregnating a porous refractory support having a surface area from 0.03 m2/g to 10 m2/g with a solution of a compound of an alkali metal having an atomic number from 19 through 55 in such concentration as to produce - optionally after extraction with a solvent after either step (b) or (c) indicated below - in the final catalyst a content from 0.25 to 16 milligram equivalent weights of the alkali metal per kilogram total catalyst for each square meter of support surface area per gram of catalyst support((mgew/kg)/(m2/g));
(b) at least partially drying the impregnated support of step (a);
(c) contacting the product of step (b) with a liquid phase containing a dissolved silver compound or a slurry of particles of silver or a silver compound in an amount sufficient to deposit from 1 to 25 per cent by weight of silver, based on the total catalyst, on the support surface, and (d) thermally treating the product of step (c), to convert the silver compound to silver metal.
(a) impregnating a porous refractory support having a surface area from 0.03 m2/g to 10 m2/g with a solution of a compound of an alkali metal having an atomic number from 19 through 55 in such concentration as to produce - optionally after extraction with a solvent after either step (b) or (c) indicated below - in the final catalyst a content from 0.25 to 16 milligram equivalent weights of the alkali metal per kilogram total catalyst for each square meter of support surface area per gram of catalyst support((mgew/kg)/(m2/g));
(b) at least partially drying the impregnated support of step (a);
(c) contacting the product of step (b) with a liquid phase containing a dissolved silver compound or a slurry of particles of silver or a silver compound in an amount sufficient to deposit from 1 to 25 per cent by weight of silver, based on the total catalyst, on the support surface, and (d) thermally treating the product of step (c), to convert the silver compound to silver metal.
2. Silver catalysts as claimed in claim 1, in which the content of the alkali metal in the final catalyst is in the range from 0.25 to 14 (mgew/kg)/(m2/g).
3. Silver catalysts as claimed in claim 2, in which the content of the alkali metal in the final catalyst is in the range from 0.5 to 14 (mgew/
kg)/(m2/g).
kg)/(m2/g).
4. Silver catalysts as claimed in claim 1, in which the alkali metal content in the final catalyst ranges from 1 to 9 milligram equivalent weights per kilogram total catalyst for each square meter of surface area per gram of catalyst support.
5. Silver catalysts as claimed in claim 4, in which the alkali metal content in the final catalyst ranges from 2 to 8 milligram equivalent weights per kilogram total catalyst for each square meter of surface area per gram of catalyst support.
6. Silver catalysts as claimed in claim 1, 2 or 5, in which the alkali metal is cesium.
7. Silver catalysts as claimed in claim 1, in which the porous refrac-tory support comprises alpha alumina.
8. Silver catalysts as claimed in claim 7, in which the surface area of the support is in the range from 0.1 to 7 m2/g.
9. Silver catalysts as claimed in claim 1, 2 or 5, of which the thermal treatment of step (d) is carried out in the presence of a reducing agent.
10. Silver catalysts as claimed in claim 1, in which the catalyst contains from 2 to 20 per cent by weight of silver.
11. Silver catalysts as claimed in claim 10, in which the catalyst contains from 4 to 16 per cent by weight of silver.
12. A process for the preparation of silver catalysts as claimed in claim 1, which comprises:
(a) impregnating a porous refractory support having a surface area from 0.03 m2/g to 10 m2/g with a solution of a compound of an alkali metal having an atomic number from 19 through 55 in such concentration as to produce -optionally after extraction with a solvent after either step (b) or (c) indi-cated below - in the final catalyst a content from 0.25 to 16 milligram equivalent weights of the alkali metal per kilogram total catalyst for each square metre of support surface area per gram of catalyst support ((mgew/kg)/
(m2/g));
(b) at least partially drying the impregnated support of step (a);
(c) contacting the product of step (b) with a liquid phase containing a dissolved silver compound or a slurry of particles of silver or a silver compound to deposit from 1 to 25 per cent by weight of silver, based on the total catalyst, on the support surface, and (d) thermally treating the product of step (c), to convert the silver compound to silver metal.
(a) impregnating a porous refractory support having a surface area from 0.03 m2/g to 10 m2/g with a solution of a compound of an alkali metal having an atomic number from 19 through 55 in such concentration as to produce -optionally after extraction with a solvent after either step (b) or (c) indi-cated below - in the final catalyst a content from 0.25 to 16 milligram equivalent weights of the alkali metal per kilogram total catalyst for each square metre of support surface area per gram of catalyst support ((mgew/kg)/
(m2/g));
(b) at least partially drying the impregnated support of step (a);
(c) contacting the product of step (b) with a liquid phase containing a dissolved silver compound or a slurry of particles of silver or a silver compound to deposit from 1 to 25 per cent by weight of silver, based on the total catalyst, on the support surface, and (d) thermally treating the product of step (c), to convert the silver compound to silver metal.
13. A process as claimed in claim 12, in which the solution used in step (a) is an aqueous solution.
14. A process as claimed in claim 12, in which a final catalyst is produced of which the content of the alkali metal is in the range from 0.25 to 14 (mgew/kg)/(m2/g).
15. A process as claimed in claim 14, in which a final catalyst is produced of which the content of the alkali metal is in the range from 0.5 to 14 (mgew/kg)/(m2/g).
16. A process as claimed in claim 12, in which a final catalyst is produced of which the alkali metal content ranges from 1 to 9 milligram equivalent weights per kilogram total catalyst for each square meter of sur-face area per gram of catalyst support.
17. A process as claimed in claim 16, in which a final catalyst is produced of which the alkali metal content ranges from 2 to 8 milligram equivalent weights per kilogram total catalyst for each square meter of sur-face area per gram of catalyst support.
18. A process as claimed in claim 12, 15 or 17, in which cesium is used as the alkali metal.
19. A process as claimed in claim 12, in which the porous refractory support used comprises alpha alumina.
20. A process as claimed in claim 19, in which the porous refractory support used has a surface area in the range from 0.1 to 7 m2/g.
21. A process as claimed in claim 12, 17 or 20, in which the thermal treatment of step (d) is carried out in the presence of a reducing agent.
22. A process as claimed in claim 12, in which a final catalyst is produced of which the silver deposited is in the range from 2 to 20 per cent by weight.
23. A process as claimed in claim 22, in which a final catalyst is produced of which the silver deposited is in the range from 4 to 16 per cent by weight.
24. A process as claimed in claim 12, 17 or 23, in which the drying in step (b) is conducted in a stream of nitrogen at a temperature in the range from 100°C to 200°C.
25. A process as claimed in any one of claim 12, 20 or 23, in which the thermal treatment in step (d) is carried out at a temperature in the range from 100°C to 375°C.
26. A process as claimed in claim 12, in which the liquid phase in step (c) is an aqueous solution comprising a silver salt of a carboxylic acid and an organic amine alkaline solubilizing/reducing agent.
27. A process as claimed in claim 26, in which 1,2-diaminoethane is used as the solubilizing/reducing agent.
28. A process for the production of ethylene oxide by direct oxidation of ethylene in the vapour phase with molecular oxygen at ethylene oxide form-ing conditions at a temperature in the range from 210°C to 285°C in the presence of a fixed bed of a silver catalyst, which process is conducted in the presence of a silver catalyst as claimed in any one of claim 1, 2 or 5.
29. A process for the production of ethylene oxide by direct oxidation of ethylene in the vapour phase with molecular oxygen at ethylene oxide form-ing conditions at a temperature in the range from 210°C to 285°C in the presence of a fixed bed of a silver catalyst, which process is conducted in the presence of a silver catalyst as claimed in any one of claim 8, 10 or 11.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB49962/73A GB1489335A (en) | 1973-10-26 | 1973-10-26 | Catalyst for the production of ethylene oxide |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1048010A true CA1048010A (en) | 1979-02-06 |
Family
ID=10454139
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA210,866A Expired CA1048010A (en) | 1973-10-26 | 1974-10-07 | Catalyst for the production of ethylene oxide |
Country Status (15)
| Country | Link |
|---|---|
| JP (1) | JPS581629B2 (en) |
| BE (1) | BE821439A (en) |
| CA (1) | CA1048010A (en) |
| CS (1) | CS219313B2 (en) |
| DD (1) | DD114407A5 (en) |
| DE (1) | DE2448449C2 (en) |
| ES (2) | ES431308A1 (en) |
| FR (1) | FR2249087B1 (en) |
| GB (1) | GB1489335A (en) |
| IN (1) | IN143192B (en) |
| IT (1) | IT1025175B (en) |
| NL (1) | NL7413748A (en) |
| PL (1) | PL99702B1 (en) |
| RO (1) | RO84369B (en) |
| SE (2) | SE407156B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11213806B1 (en) | 2018-06-21 | 2022-01-04 | Mid-Atlantic Technology, Research & Innovation Center, Inc. | Catalyst supports—composition and process of manufacture |
| US11396007B2 (en) | 2018-06-21 | 2022-07-26 | Mid-Atlantic Technology, Research & Innovation Center | Catalyst supports—composition and process of manufacture |
Families Citing this family (21)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2640540B2 (en) * | 1976-09-09 | 1978-10-19 | Basf Ag, 6700 Ludwigshafen | Catalyst for the production of ethylene oxide |
| US4066575A (en) * | 1976-07-26 | 1978-01-03 | Halcon International, Inc. | Process for the preparation of a supported silver catalyst |
| DE2819595A1 (en) * | 1977-05-12 | 1978-12-07 | Basf Ag | CATALYST FOR THE PRODUCTION OF ETHYLENE OXIDE |
| JPS5689843A (en) * | 1979-12-25 | 1981-07-21 | Nippon Shokubai Kagaku Kogyo Co Ltd | Silver catalyst for production of ethylene oxide |
| US4419276A (en) | 1981-09-30 | 1983-12-06 | Union Carbide Corporation | Silver catalyst for the manufacture of ethylene oxide and a process for preparing the catalyst |
| US4455392A (en) * | 1981-10-05 | 1984-06-19 | Union Carbide Corporation | Process for preparing a supported silver catalyst |
| BG37835A3 (en) * | 1982-06-30 | 1985-08-15 | Hoechst Ag,De | Method for preparing silver catalyst |
| US4575494A (en) * | 1984-02-08 | 1986-03-11 | The Dow Chemical Company | Alumina compositions useful as catalyst supports for ethylene oxidation |
| JPS60216844A (en) * | 1984-04-13 | 1985-10-30 | Nippon Shokubai Kagaku Kogyo Co Ltd | Silver catalyst for producing ethylene oxide |
| BRPI0312010B1 (en) | 2002-06-28 | 2017-11-28 | Shell Internationale Research Maatschappij B.V | METHOD FOR DETAINING AN EPOXIDATION PROCESS AND A PROCESS FOR EPOXIDATION OF AN OLEFINE |
| JP4537848B2 (en) * | 2002-06-28 | 2010-09-08 | シエル・インターナシヨナル・リサーチ・マートスハツペイ・ベー・ヴエー | Process for improving catalyst selectivity and process for epoxidation of olefins |
| US7348444B2 (en) | 2003-04-07 | 2008-03-25 | Shell Oil Company | Process for the production of an olefin oxide |
| US6846774B2 (en) * | 2003-04-23 | 2005-01-25 | Scientific Design Co., Inc. | Ethylene oxide catalyst |
| CA2524890C (en) * | 2003-05-07 | 2012-09-11 | Shell Internationale Research Maatschappij B.V. | Silver-containing catalysts, the manufacture of such silvercontaining catalysts, and the use thereof |
| US20040225138A1 (en) | 2003-05-07 | 2004-11-11 | Mcallister Paul Michael | Reactor system and process for the manufacture of ethylene oxide |
| US8148555B2 (en) | 2003-06-26 | 2012-04-03 | Shell Oil Company | Method for improving the selectivity of a catalyst and a process for the epoxidation of an olefin |
| BRPI0515905A (en) | 2004-09-24 | 2008-08-12 | Shell Int Research | a process for selecting molded particles, a process for installing a system, a process for reacting a gaseous feed load on such a system, a computer program product, and a computer system |
| JP5542659B2 (en) | 2007-05-09 | 2014-07-09 | シエル・インターナシヨナル・リサーチ・マートスハツペイ・ベー・ヴエー | Epoxidation catalyst, method for preparing catalyst, and method for producing olefin oxide, 1,2-diol, 1,2-diol ether, 1,2-carbonate or alkanolamine |
| CA2723517C (en) | 2008-05-07 | 2017-03-07 | Shell Internationale Research Maatschappij B.V. | A process for the start-up of an epoxidation process, a process for the production of ethylene oxide, a 1,2-diol, a 1,2-diol ether, a 1,2-carbonate, or an alkanolamine |
| CN102066348B (en) | 2008-05-07 | 2013-09-25 | 国际壳牌研究有限公司 | A process for the production of an olefin oxide, a 1,2-diol, a 1,2-diol ether, a 1,2-carbonate, or an alkanolamine |
| BR112019011162B1 (en) | 2016-12-02 | 2022-08-16 | Shell Internationale Research Maatschappij B.V. | METHOD FOR THE CONDITIONING OF AN ETHYLENE EPOXIDATION CATALYST AND METHOD TO IMPROVE THE SELECTIVITY OF SUCH CATALYST IN AN ETHYLENE EPOXIDATION PROCESS |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| BE793658A (en) * | 1972-01-07 | 1973-07-04 | Shell Int Research | CATALYST USED FOR THE PRODUCTION OF ETHYLENE OXIDE |
-
1973
- 1973-10-26 GB GB49962/73A patent/GB1489335A/en not_active Expired
-
1974
- 1974-10-03 SE SE7412461A patent/SE407156B/en not_active IP Right Cessation
- 1974-10-07 CA CA210,866A patent/CA1048010A/en not_active Expired
- 1974-10-10 DE DE2448449A patent/DE2448449C2/en not_active Expired
- 1974-10-21 NL NL7413748A patent/NL7413748A/en active Search and Examination
- 1974-10-22 IN IN2330/CAL/74A patent/IN143192B/en unknown
- 1974-10-24 BE BE149849A patent/BE821439A/en not_active IP Right Cessation
- 1974-10-24 IT IT28761/74A patent/IT1025175B/en active
- 1974-10-24 JP JP49122005A patent/JPS581629B2/en not_active Expired
- 1974-10-24 FR FR7435691A patent/FR2249087B1/fr not_active Expired
- 1974-10-24 ES ES431308A patent/ES431308A1/en not_active Expired
- 1974-10-25 PL PL1974175085A patent/PL99702B1/en unknown
- 1974-10-25 DD DD181925A patent/DD114407A5/xx unknown
- 1974-10-25 CS CS747326A patent/CS219313B2/en unknown
- 1974-10-25 RO RO80324A patent/RO84369B/en unknown
-
1976
- 1976-05-06 ES ES447632A patent/ES447632A1/en not_active Expired
-
1978
- 1978-08-24 SE SE7808959A patent/SE434837B/en not_active IP Right Cessation
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11213806B1 (en) | 2018-06-21 | 2022-01-04 | Mid-Atlantic Technology, Research & Innovation Center, Inc. | Catalyst supports—composition and process of manufacture |
| US11396007B2 (en) | 2018-06-21 | 2022-07-26 | Mid-Atlantic Technology, Research & Innovation Center | Catalyst supports—composition and process of manufacture |
| US11547985B2 (en) | 2018-06-21 | 2023-01-10 | Mid-Atlantic Technology, Research Innovation Center, Inc. | Catalyst supports—composition and process of manufacture |
| US11772082B1 (en) | 2018-06-21 | 2023-10-03 | Avn Corporation | Catalyst supports—composition and process of manufacture |
Also Published As
| Publication number | Publication date |
|---|---|
| PL99702B1 (en) | 1978-08-31 |
| SE7808959L (en) | 1978-08-24 |
| GB1489335A (en) | 1977-10-19 |
| SE7412461L (en) | 1975-04-28 |
| DE2448449C2 (en) | 1986-03-06 |
| SE407156B (en) | 1979-03-19 |
| FR2249087B1 (en) | 1976-10-22 |
| BE821439A (en) | 1975-04-24 |
| DE2448449A1 (en) | 1975-04-30 |
| FR2249087A1 (en) | 1975-05-23 |
| ES447632A1 (en) | 1977-06-16 |
| RO84369A (en) | 1984-06-21 |
| RO84369B (en) | 1984-08-30 |
| CS219313B2 (en) | 1983-03-25 |
| DD114407A5 (en) | 1975-08-05 |
| JPS5074589A (en) | 1975-06-19 |
| IN143192B (en) | 1977-10-15 |
| IT1025175B (en) | 1978-08-10 |
| NL7413748A (en) | 1975-04-29 |
| ES431308A1 (en) | 1976-11-16 |
| JPS581629B2 (en) | 1983-01-12 |
| SE434837B (en) | 1984-08-20 |
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