A tableted catalyst support, characterized by an alpha-alumina content of at least 85 wt.-%, a pore volume of at least 0.40 mL/g, as determined by mercury porosimetry, and a BET surface area of 0.5 to 5.0 m.sup.2/g. The tableted catalyst support is an alpha-alumina catalyst support obtained with high geometrical precision and displaying a high overall pore volume, thus allowing for impregnation with a high amount of silver, while exhibiting a surface area sufficiently large so as to provide optimal dispersion of catalytically active species, in particular metal species. The invention further provides a process for producing a tableted alpha-alumina catalyst support, which comprises i) forming a free-flowing feed mixture comprising, based on inorganic solids content, at least 50 wt.-% of a transition alumina; ii) tableting the free-flowing feed mixture to obtain a compacted body; and iii) heat treating the compacted body at a temperature of at least 1100° C., preferably at least 1300° C., more preferably at least 1400° C., in particular at least 1450° C., to obtain the tableted alpha-alumina catalyst support. The invention moreover relates to a compacted body obtained by tableting a free-flowing feed mixture which comprises, based on inorganic solids content, at least 50 wt.-% of a transition alumina having a loose bulk density of at most 600 g/L, a pore volume of at least 0.6 mL/g, as determined, and a median pore diameter of at least 15 nm. The invention moreover relates to a shaped catalyst body for producing ethylene oxide by gas-phase oxidation of ethylene, comprising at least 15 wt.-% of silver, relative to the total weight of the catalyst, deposited on the tableted alpha-alumina catalyst support. The invention moreover relates to a process for producing ethylene oxide by gas-phase oxidation of ethylene, comprising reacting ethylene and oxygen in the presence of the shaped catalyst body.

A tableted catalyst support, characterized by an alpha-alumina content of at least 85 wt.-%, a pore volume of at least 0.40 mL/g, as determined by mercury porosimetry, and a BET surface area of 0.5 to 5.0 m.sup.2/g. The tableted catalyst support is an alpha-alumina catalyst support obtained with high geometrical precision and displaying a high overall pore volume, thus allowing for impregnation with a high amount of silver, while exhibiting a surface area sufficiently large so as to provide optimal dispersion of catalytically active species, in particular metal species. The invention further provides a process for producing a tableted alpha-alumina catalyst support, which comprises i) forming a free-flowing feed mixture comprising, based on inorganic solids content, at least 50 wt.-% of a transition alumina; ii) tableting the free-flowing feed mixture to obtain a compacted body; and iii) heat treating the compacted body at a temperature of at least 1100° C., preferably at least 1300° C., more preferably at least 1400° C., in particular at least 1450° C., to obtain the tableted alpha-alumina catalyst support. The invention moreover relates to a compacted body obtained by tableting a free-flowing feed mixture which comprises, based on inorganic solids content, at least 50 wt.-% of a transition alumina having a loose bulk density of at most 600 g/L, a pore volume of at least 0.6 mL/g, as determined, and a median pore diameter of at least 15 nm. The invention moreover relates to a shaped catalyst body for producing ethylene oxide by gas-phase oxidation of ethylene, comprising at least 15 wt.-% of silver, relative to the total weight of the catalyst, deposited on the tableted alpha-alumina catalyst support. The invention moreover relates to a process for producing ethylene oxide by gas-phase oxidation of ethylene, comprising reacting ethylene and oxygen in the presence of the shaped catalyst body.

A process for preparing a silver-containing catalyst for the oxidation of ethylene to ethylene oxide (EO) including the steps of: providing a support having pores; providing a silver-containing impregnation solution; adding an amount of surfactant to the impregnation solution; contacting the support with the surfactant-containing impregnation solution; and removing at least a portion of the impregnation solution prior to fixing the silver upon the carrier in a manner which preferentially removes impregnation solution not contained in the pores. The use of the surfactant results in improved drainage of the silver impregnation solution from the carrier exteriors during the catalyst synthesis. As a result, the amount of silver-containing impregnation solution necessary for the synthesis of the EO catalyst was reduced by up to 15% without reducing the catalyst performance.

A process for preparing a silver-containing catalyst for the oxidation of ethylene to ethylene oxide (EO) including the steps of: providing a support having pores; providing a silver-containing impregnation solution; adding an amount of surfactant to the impregnation solution; contacting the support with the surfactant-containing impregnation solution; and removing at least a portion of the impregnation solution prior to fixing the silver upon the carrier in a manner which preferentially removes impregnation solution not contained in the pores. The use of the surfactant results in improved drainage of the silver impregnation solution from the carrier exteriors during the catalyst synthesis. As a result, the amount of silver-containing impregnation solution necessary for the synthesis of the EO catalyst was reduced by up to 15% without reducing the catalyst performance.

A process for producing a silver-based epoxidation catalyst, comprising i) impregnating a particulate porous refractory support with a first aqueous silver impregnation solution comprising silver ions and an aminic complexing agent selected from amines, alkanolamines and amino acids; ii) converting at least part of the silver ions impregnated on the refractory support to metallic silver by heating while directing a stream of a first gas over the impregnated refractory support to obtain an intermediate catalyst, wherein the first gas comprises at least 5 vol.-% oxygen; iii) impregnating the intermediate catalyst with a second aqueous silver impregnation solution comprising silver ions, an aminic complexing agent selected from amines, alkanolamines and amino acids, and one or more transition metal promoters, in particular rhenium; and iv) converting at least part of the silver ions impregnated on the intermediate catalyst to metallic silver by heating while directing a stream of a second gas over the impregnated intermediate catalyst to obtain the epoxidation catalyst, wherein the second gas comprises at most 2.0 vol.-% oxygen, wherein the impregnated refractory support and the impregnated intermediate catalyst are each heated to a temperature of 200 to 800° C. The process of the invention surprisingly allows for obtaining a catalyst with high selectivity in a cost-efficient manner. The invention also relates to a silver-based epoxidation catalyst obtainable by such a process, and to a process for producing an alkylene oxide by gas-phase oxidation of an alkylene, comprising reacting an alkylene and oxygen in the presence of a silver-based epoxidation catalyst obtainable by the above process.

A process for producing a silver-based epoxidation catalyst, comprising i) impregnating a particulate porous refractory support with a first aqueous silver impregnation solution comprising silver ions and an aminic complexing agent selected from amines, alkanolamines and amino acids; ii) converting at least part of the silver ions impregnated on the refractory support to metallic silver by heating while directing a stream of a first gas over the impregnated refractory support to obtain an intermediate catalyst, wherein the first gas comprises at least 5 vol.-% oxygen; iii) impregnating the intermediate catalyst with a second aqueous silver impregnation solution comprising silver ions, an aminic complexing agent selected from amines, alkanolamines and amino acids, and one or more transition metal promoters, in particular rhenium; and iv) converting at least part of the silver ions impregnated on the intermediate catalyst to metallic silver by heating while directing a stream of a second gas over the impregnated intermediate catalyst to obtain the epoxidation catalyst, wherein the second gas comprises at most 2.0 vol.-% oxygen, wherein the impregnated refractory support and the impregnated intermediate catalyst are each heated to a temperature of 200 to 800° C. The process of the invention surprisingly allows for obtaining a catalyst with high selectivity in a cost-efficient manner. The invention also relates to a silver-based epoxidation catalyst obtainable by such a process, and to a process for producing an alkylene oxide by gas-phase oxidation of an alkylene, comprising reacting an alkylene and oxygen in the presence of a silver-based epoxidation catalyst obtainable by the above process.

There is provided a method of producing ethylene oxide and ethylene glycol capable of reducing a concentration in discharged water of 1,4-dioxane contained generated in a step of producing ethylene oxide and ethylene glycol. A method of producing ethylene oxide and ethylene glycol includes a predetermined step of producing ethylene oxide, and a step of extracting a part of a column bottom liquid of an ethylene oxide stripping column in the step of producing ethylene oxide and supplying the extracted column bottom liquid to a by-produced ethylene glycol concentration column, concentrating ethylene glycol produced as a by-product in the step of producing ethylene oxide, and distilling and separating 1,4-dioxane produced as a by-product in the step of producing ethylene oxide, wherein the by-produced ethylene glycol concentration column is a divided wall distillation column.

There is provided a method of producing ethylene oxide and ethylene glycol capable of reducing a concentration in discharged water of 1,4-dioxane contained generated in a step of producing ethylene oxide and ethylene glycol. A method of producing ethylene oxide and ethylene glycol includes a predetermined step of producing ethylene oxide, and a step of extracting a part of a column bottom liquid of an ethylene oxide stripping column in the step of producing ethylene oxide and supplying the extracted column bottom liquid to a by-produced ethylene glycol concentration column, concentrating ethylene glycol produced as a by-product in the step of producing ethylene oxide, and distilling and separating 1,4-dioxane produced as a by-product in the step of producing ethylene oxide, wherein the by-produced ethylene glycol concentration column is a divided wall distillation column.

Disclosed herein are methods of using scaled selectivities to assist in determining whether changes to the value of a target ethylene oxide production parameter—such as ethylene oxide production rate—used in the process of epoxidizing ethylene with a high-selectivity catalyst, have caused the process to move away from optimal operation. If the deviation from optimal operation has not worsened, it is generally unnecessary to perform a full optimization study even if the value of a target ethylene oxide production parameter has changed, which reduces or eliminates process disturbances caused by carrying out such studies. Methods are also disclosed which use both scaled selectivities and scaled reaction temperatures. If scaled selectivities reveal that a change in the value of a target ethylene oxide production parameter has moved the process away from optimal operation, scaled reaction temperatures can, under certain conditions, provide an indication of the directions in which the reaction temperature and/or overall catalyst chloriding effectiveness should be changed to move toward optimal operation. If a change in the value of a target ethylene oxide production parameter has improved the scaled selectivity, the scaled reaction temperature may also be used to guide further adjustments which may further improve scaled selectivity.

Disclosed herein are methods of using scaled selectivities to assist in determining whether changes to the value of a target ethylene oxide production parameter—such as ethylene oxide production rate—used in the process of epoxidizing ethylene with a high-selectivity catalyst, have caused the process to move away from optimal operation. If the deviation from optimal operation has not worsened, it is generally unnecessary to perform a full optimization study even if the value of a target ethylene oxide production parameter has changed, which reduces or eliminates process disturbances caused by carrying out such studies. Methods are also disclosed which use both scaled selectivities and scaled reaction temperatures. If scaled selectivities reveal that a change in the value of a target ethylene oxide production parameter has moved the process away from optimal operation, scaled reaction temperatures can, under certain conditions, provide an indication of the directions in which the reaction temperature and/or overall catalyst chloriding effectiveness should be changed to move toward optimal operation. If a change in the value of a target ethylene oxide production parameter has improved the scaled selectivity, the scaled reaction temperature may also be used to guide further adjustments which may further improve scaled selectivity.