Catalyst for the oxidation of ethylene to ethylene oxide

Abstract

The present invention is directed to a shaped catalyst body for preparing ethylene oxide, which comprises at least silver, cesium and rhenium applied to an alumina support, wherein the alumina support comprises Si, Ca, and Mg in a defined amount. Furthermore, the present invention is directed to a process for preparing the catalyst according to the present invention and process for preparing ethylene oxide by gas-phase oxidation of ethylene by means of oxygen in the presence of a shaped catalyst body according to the present invention.

Claims

1. A shaped catalyst body for preparing ethylene oxide, which comprises silver, cesium and rhenium applied to an alumina support, wherein the alumina support comprises Si with the Si content in the carrier being defined as Cs, and measured in ppm per total support weight, Ca with the Ca content in the carrier being defined as C.sub.Ca, and measured in ppm per total support weight, and Mg with the Mg content in the carrier being defined as C.sub.Mg and measured in ppm per total support weight, wherein the value of the expression R1=C.sub.si/AW.sub.si−C.sub.Ca/AW.sub.Ca−C.sub.Mg/AW.sub.Mg is in the range of 1 to 100 mmol/kg per weight of the carrier, and AW.sub.Si, AW.sub.Ca, and AW.sub.Mg relate to atomic weight of Si, Ca and Mg in g/mol, respectively, and wherein the catalyst comprises Ag with the Ag content in the catalyst being defined as C.sub.Ag and measured in weight percent per total catalyst weight, Cs with the Cs content in the catalyst being defined as C.sub.Cs and measured in ppm per total catalyst weight, Re with the Re content in the catalyst being defined as C.sub.Re and measured in ppm per total catalyst weight, wherein the value of the expression R2=C.sub.Cs/AW.sub.Cs−C.sub.Re/AW.sub.Re is in the range of 1.0 to 5.0 mmol/kg per weight of total catalyst, and AW.sub.Cs, and AW.sub.Re, relate to atomic weight of Cs and Re in g/mol, respectively and the value of the expression R3=R2/[R1×(100−C.sub.Ag)/100] is in the range of 0.05 to 1, and further comprising rhenium, and cesium, in amounts such that the rhenium content C.sub.Re exceeds 450 ppm per weight of the total catalyst, and the cesium content C.sub.cs exceeds 450 ppm per weight of the total catalyst.

2. The shaped catalyst body according to claim 1, wherein the Si content in the carrier C.sub.si is in the range from 200 to 4000 ppm based on the total weight of the support and calculated as element.

3. The shaped catalyst body according to claim 1, wherein the Ca content in the carrier C.sub.Ca is in the range from 100 to 1000 ppm based on the total weight of the support and calculated as element.

4. The shaped catalyst body according to claim 1, wherein the alumina support comprises up to 1000 ppm of magnesium, based on the total weight of the support and calculated as element.

5. The shaped catalyst body according to any of claim 1, wherein the alumina support has a BET surface area in the range from 0.95 to 3.0 m.sup.2/g.

6. The shaped catalyst body according to claim 1, wherein the alumina support has at least two pore size distributions wherein at least one of the pore size distributions is within a pore size range of about 0.1 to 5 μm.

7. The shaped catalyst body according to claim 1, wherein the shaped catalyst body comprises silver in an amount of from 5 to 40% by weight, based on the total weight of the shaped catalyst body and calculated as element.

8. The shaped catalyst body according to claim 1, wherein the catalyst comprises at least one promoter selected from the group consisting of elements of groups IA, VIB, VIIB and VIA.

9. The shaped catalyst body according to claim 1, wherein the value of the expression R1 is in the range of 5 to 75 mmol/kg per weight of the carrier.

10. The shaped catalyst body according to claim 1, wherein the value of the expression R1 is in the range of 10 to 60 mmol/kg per weight of the carrier.

11. The shaped catalyst body according to claim 1, wherein the catalyst comprises at least one promoter selected from the group consisting of tungsten, lithium and sulfur.

12. The shaped catalyst body according to claim 1, wherein the value of the expression R2 is in the range of 1.346 to 5.0 mmol/kg per weight of total catalyst.

13. A process for preparing ethylene oxide by gas-phase oxidation of ethylene by means of oxygen in the presence of a shaped catalyst body according to claim 1.

14. A process for producing a shaped catalyst body comprising silver and rhenium applied to an alumina support, which comprises (a) providing an alumina support; (b) applying silver, cesium and rhenium to the alumina support, wherein for the alumina support, the value of the expression R1=C.sub.Si/AW.sub.Si−C.sub.Ca/AW.sub.Ca−C.sub.Mg/AW.sub.Mg is in the range of 1 to 100 mmol/kg per weight of the carrier, and AW.sub.Si, AW.sub.Ca, and AW.sub.Mg relate to atomic weight of Si, Ca and Mg in g/mol, respectively, and and rhenium and cesium are applied in amounts such that the value of the expression R2=C.sub.Ca/AW.sub.Cs−C.sub.Re/AW.sub.Re is in the range of 1.0 to 5.0 mmol/kg per weight of total catalyst, and AW.sub.Cs, and AW.sub.Re relate to atomic weight of Cs and Re in g/mol, respectively and the value of the expression R3=R2/[R1×(100−CAg)/100] is in the range of 0.05 to 1, and further comprising rhenium, and cesium, in amounts such that the rhenium content C.sub.Re exceeds 450 ppm per weight of the total catalyst, and the cesium content C.sub.Cs exceeds 450 ppm per weight of the total catalyst.

15. The process according to claim 14, wherein the process further comprises (c) calcining the alumina support obtained according to (b).

16. The process according to claim 14, wherein silver is applied in an amount of from 5 to 35% by weight, based on the total weight of the shaped catalyst body and calculated as element, in (b).

17. The process according to claim 14, wherein for the alumina support, the value of the expression R1 is in the range of 5 to 75 mmol/kg per weight of the carrier.

18. The process according to claim 14, wherein for the alumina support, the value of the expression R1 is in the range of 10 to 60 mmol/kg per weight of the carrier.

19. A shaped catalyst body obtained by the process according to claim 14.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) FIG. 1 shows testing data of the inventive catalyst 3.2.2.16 (white markers) and of the comparative catalyst 3.2.2.15 (black markers). On the x-axis, the time on stream in [hours] is plotted. On the left y-axis, selectivity is plotted in [%]. On the right y-axis, coolant temperature is plotted in [° C.].

(2) Examples will be used below to illustrate the invention.

EXAMPLES

(3) 1. Characterization Methods

(4) 1.1 Analysis of Total Amount of Ca-, Mg-, and Si-Impurities in Alumina Carriers

(5) 1.1.1 Sample Preparation for Measurement of Ca, Mg, and Si

(6) Approximately 100-200 mg (at an error margin of ±0.1 mg) of the aluminum oxide carrier sample were weighted into a platinum crucible. 1.0 g of lithium metaborate (LiBO.sub.2) was added. The mixture was melted in an automated fusion apparatus with a temperature ramp up to max. 1150° C.

(7) After cooling down, the melt was dissolved in deionized water by careful heating. Then, 10 ml of semi-concentrated hydrochloric acid (concentrated HCl diluted with deionized water, volume ratio 1:1 corresponds to about 6M) was added. Finally, the solution was filled up to a volume of 100 ml with deionized water.

(8) 1.1.2 Measurement of Ca, Mg, and Si

(9) Ca, Mg, and Si from the sample solution 1.1.1 were determined by Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES). Apparatus: ICP-OES Varian Vista Pro Parameters: Wavelengths [nm]: Ca 317.933 Mg 285.213 Si 251.611 Integration time: 10 s Nebulizer: Conikal 3 ml Nebulizer pressure: 270 kPa Pump rate: 30 rpm Calibration: external (matrix-matched standards)
2. Carriers

(10) Si-, Ca- and Mg-content [ppm] per total weight of the carrier and carrier BET surface area are summarized in Table 1.

(11) TABLE-US-00001 TABLE 1 Total Si-, Ca-, and Mg-content [ppm] per weight carrier and carrier BET-surface area [m.sup.2/g] A B C D E Si-content [ppm] 900 900 700 800 700 Ca-content [ppm] 300 300 200 300 300 Mg-content [ppm] 200 100 100 200 100 BET surface area 0.88 0.91 1.12 1.29 1.37 [m.sup.2/g] F G H I J Si-content [ppm] 900 700 2300 2400 700 Ca-content [ppm] 300 300 400 400 300 Mg-content [ppm] 200 100 400 500 100 BET surface area 1.41 1.57 1.42 1.84 1.06 [m.sup.2/g]
3. Preparation of Catalysts
3.1 Production of the Silver Complex Solution

(12) 550 g of silver nitrate were completely dissolved in 1.5 l of water under constant stirring and the solution was warmed to 40° C. 402 g of KOH (47.8%) was mixed with 1.29 L water. A separate solution of 216.3 g oxalic acid was added to the KOH solution, which was then warmed to 40° C. The potassium oxalate solution was then added to the silver nitrate solution within 45 min (volume flow rate ca. 33 ml/min) with the aid of a dosing pump and the solution was stirred for approximately 1 h at 40° C. The precipitated silver oxalate was then filtered and the obtained filter cake was washed with 1 L water portions until the filter cake was free of potassium and nitrate (ca. 10 l total). The water was removed from the filter cake by flowing air through the filter apparatus and the water content of the filter cake was measured. Typically a cake of 620 g with a water content of 20.8% was obtained.

(13) Ethylenediamine (306 g) was cooled in an ice bath to ca. 10° C. and 245 g water was added in small portions. At the end of the water addition, 484.7 g of the (still damp) silver oxalate was added to the ethylenediamine/water mixture within 30 minutes. The mixture was stirred at room temperature overnight and any undissolved material removed via centrifugation. The silver content was determined refractometrically and the density was measured.

(14) The obtained solution contained 28.0-29.3 weight % silver and had a density of 1.512-1.532 g/mL.

(15) 3.2. Preparation of Ag Containing Catalysts with an Ag Content of >20 wt.-% (Double Impregnation)

(16) 3.2.1 Preparation of Ag-Containing Intermediate Products

(17) An amount of carrier A-D listed in Table 2 was placed into a 2 L glass flask. The flask was attached to a rotary evaporator which was set under vacuum pressure of 30 mbar. The rotary evaporator system was set in rotation of 30 rpm. An amount of the silver complex solution listed in Table 2 was added onto the carrier A-D over 15 minutes under vacuum of 30 mbar. After addition of the silver complex solution, the rotary evaporator system was continued to rotate under vacuum for another 15 minutes. The impregnated carrier was then left in the apparatus at room temperature and atmospheric pressure for 1 hour and mixed gently every 15 minutes.

(18) The impregnated carrier was calcined for 12 minutes at 290° C. under 23 m.sup.3/h flowing nitrogen in a calcination oven to yield a Ag-containing intermediate products.

(19) TABLE-US-00002 TABLE 2 Carrier name and amounts of ingredients used for preparation of Ag- containing intermediate products 3.2.1.1-3.2.1.4. Intermediate Intermediate Intermediate Intermediate 3.2.1.1 3.2.1.2 3.2.1.3 3.2.1.4 Carrier name Carrier A Carrier B Carrier C Carrier D Amount of 173.6 173.9 173.6 348.4 carrier [g] Amount of Ag- 115.9838 115.7641 114.5389 227.7935 complex solution [g] Ag-content in 28.93 29.04 29.3 28.7 Ag-complex solution [wt %] Ag-content in 16.2 16.2 16.2 15.8 Ag-containing intermediate [wt %]
3.2.2. Preparation of Final Catalysts

(20) An amount of Ag-containing intermediate products 3.2.1.1-3.2.1.4 listed in Table 3 were placed into a 2 L glass flask. The flask was attached to a rotary evaporator which was set under vacuum pressure of 30 mbar. The rotary evaporator system was set in rotation of 30 rpm. An amount of the silver complex solution listed in Table 3 prepared according to step 3.1 was mixed with an amount of promoter solution I listed in Table 3, an amount of promoter solution II listed in Table 3, an amount of promoter solution III listed in Table 3. Promoter solution I was made from dissolving lithium nitrate (FMC, 99.3%) and ammonium sulfate (Merck, 99.4%) in DI water to achieve target Li and S contents listed in Table 3. Promoter solution II was made from dissolving tungstic acid (HC Starck, 99.99%) in DI water and cesium hydroxide in water (HC Starck, 50.42%) to achieve target Cs and W contents listed in Table 3. Promoter solution III was made from dissolving ammonium perrhenate (Engelhard, 99.4%) in DI water to achieve target Re content listed in Table 3. The combined solution containing silver complex solution, promoter solutions I, II, and III was stirred for 5 minutes. The combined solution was added onto the silver-containing intermediate products 3.2.1.1-3.2.1.4 over 15 minutes under vacuum of 30 mbar. After addition of the combined solution, the rotary evaporator system was continued to rotate under vacuum for another 15 minutes. The impregnated carrier was then left in the apparatus at room temperature and atmospheric pressure for 1 hour and mixed gently every 15 minutes.

(21) The impregnated material was calcined for 10 minutes at 290° C. under 23 m.sup.3/h flowing nitrogen in a calcination oven to yield the final catalysts.

(22) TABLE-US-00003 TABLE 3 Intermediate name and amounts of ingredients used for preparation of catalysts 3.2.2.1-3.2.2.4. Catalyst 3.2.2.1 Catalyst 3.2.2.2 Catalyst 3.2.2.3 Catalyst 3.2.2.4 (comparative) (comparative) (inventive) (inventive) Ag-containing 3.2.1.1 3.2.1.2 3.2.1.3 3.2.1.4 Intermediate from Table 2 Amount of Ag- 205.2 205.1 204.0 207.6 containing Intermediate [g] Amount of Ag- 96.9312 95.8464 92.1530 89.5818 complex solution [g] Ag-content in Ag- 28.0 28.3 29.3 28.7 complex solution [wt %] Amount of promoter 1.5505 1.5501 1.5425 1.5582 solution I [g] Li-/S-content in 2.85/0.21 2.85/0.21 2.85/0.21 2.85/0.21 promoter solution I [wt %] Amount of promoter 2.3257 2.3251 2.3137 2.3373 solution II [g] Cs-/W-content in 4.0/2.0 4.0/2.0 6.0/2.0 7.0/1.9 promoter solution II [wt %] Amount of promoter 2.2122 2.2117 3.3295 4.3587 solution III [g] Re-content in 4.1 4.1 4.1 3.7 promoter solution III [wt %]

(23) Further Catalysts were prepared similar to catalysts 3.2.2.1-3.2.2.4.

(24) Catalyst compositions are listed in Table 4.

(25) TABLE-US-00004 TABLE 4 Catalyst compositions (Ag-contents are reported in percent by weight of total catalyst, dopant values are reported in parts per million by weight of total catalyst) Example Carrier Ag [wt-%] Li [ppm] S [ppm] W [ppm] Cs [ppm] Re [ppm] 3.2.2.1 A 26.0 190 14 200 400 390 (comparative) 3.2.2.2 B 26.0 190 14 200 400 390 (comparative) 3.2.2.3 C 26.0 190 14 200 600 590 (inventive) 3.2.2.4 D 25.0 190 14 190 700 690 (inventive) 3.2.2.5 E 26.0 190 14 200 700 690 (inventive) 3.2.2.6 F 25.0 190 14 190 700 690 (inventive) 3.2.2.7 G 26.0 190 14 200 800 780 (inventive) 3.2.2.8 G 26.0 190 14 200 700 690 (inventive) 3.2.2.9 G 26.0 190 14 200 900 870 (inventive) 3.2.2.10 G 26.0 190 14 200 700 870 (comparative) 3.2.2.11 H 26.0 190 14 200 600 590 (comparative) 3.2.2.12 H 26.0 190 14 200 700 690 (comparative) 3.2.2.13 H 26.0 190 14 200 500 690 (comparative) 3.2.2.14 H 26.0 190 14 200 700 490 (inventive) 3.2.2.15 H 26.0 190 14 200 600 590 (comparative) 3.2.2.16 H 26.0 190 14 200 700 490 (inventive) 3.2.2.17 I 26.0 190 14 200 700 690 (comparative) 3.2.2.18 I 26.0 190 14 200 1000 690 (inventive) 3.2.2.19 I 26.0 190 14 200 1300 690 (comparative) 3.2.2.20 I 26.0 190 14 200 800 780 (comparative) 3.2.2.21 I 26.0 190 14 200 1130 780 (inventive) 3.2.2.22 I 26.0 190 14 200 1470 780 (comparative)

(26) TABLE-US-00005 TABLE 5 Key catalyst properties with respect to claims Carrier BET Catalyst Catalyst Catalyst surface Carrier Carrier Carrier Carrier Ag- Cs- Re- Catalyst area C.sub.Si C.sub.Ca C.sub.Mg R1 content content content R2 Catalyst Example [m.sup.2/g] [ppm] [ppm] [ppm] [mmol/kg] [wt %] [ppm] [ppm] [mmol/kg] R3 3.2.2.1) 0.88 900 300 200 16.33 26.0 400 390 0.915 0.076 comparative 3.2.2.2 0.91 900 300 100 20.45 26.0 400 390 0.915 0.060 comparative 3.2.2.3 1.12 700 200 100 15.82 26.0 600 590 1.346 0.115 inventive 3.2.2.4 1.29 800 300 200 12.77 25.0 700 690 1.561 0.163 inventive 3.2.2.5 1.37 700 300 100 13.32 26.0 700 690 1.561 0.158 inventive 3.2.2.6 1.41 900 300 200 16.33 25.0 700 690 1.561 0.127 inventive 3.2.2.7 1.69 700 300 100 13.32 26.0 800 780 1.830 0.186 inventive 3.2.2.8 1.69 700 300 100 13.32 26.0 700 690 1.561 0.158 inventive 3.2.2.9 1.69 700 300 100 13.32 26.0 900 870 2.099 0.213 inventive 3.2.2.10 1.69 700 300 100 13.32 26.0 700 870 0.595 0.060 comparative 3.2.2.11 1.42 2300 400 400 55.46 26.0 600 590 1.346 0.033 comparative 3.2.2.12 1.42 2300 400 400 55.46 26.0 700 690 1.561 0.038 comparative 3.2.2.13 1.42 2300 400 400 55.46 26.0 500 690 0.056 0.001 comparative 3.2.2.14 1.42 2300 400 400 55.46 26.0 700 490 2.635 0.064 inventive 3.2.2.15 1.42 2300 400 400 55.46 26.0 600 590 1.346 0.033 comparative 3.2.2.16 1.42 2300 400 400 55.46 26.0 700 490 2.635 0.064 inventive 3.2.2.17 1.84 2400 400 500 54.90 26.0 700 690 1.561 0.038 comparative 3.2.2.18 1.84 2400 400 500 54.90 26.0 1000 690 3.818 0.094 inventive 3.2.2.19 1.84 2400 400 500 54.90 26.0 1300 690 6.076 0.150 comparative 3.2.2.20 1.84 2400 400 500 54.90 26.0 800 780 1.830 0.045 comparative 3.2.2.21 1.84 2400 400 500 54.90 26.0 1130 780 4.313 0.106 inventive 3.2.2.22 1.84 2400 400 500 54.90 26.0 1470 780 6.871 0.169 comparative
3.3. Preparation of Ag Containing Catalysts with an Ag Content of <20 wt.-% (Single Impregnation)

(27) An amount of carrier J listed in Table 6 was placed into a 2 L glass flask. The flask was attached to a rotary evaporator which was set under vacuum pressure of 30 mbar. The rotary evaporator system was set in rotation of 30 rpm. An amount of the silver complex solution listed in Table 6 prepared according to step 3.1 was mixed with an amount of promoter solution I listed in Table 6, an amount of promoter solution II listed in Table 6, an amount of promoter solution III listed in Table 6. Promoter solution I was made from dissolving lithium nitrate (FMC, 99.3%) and ammonium sulfate (Merck, 99.4%) in DI water to achieve target Li and S contents listed in Table 6. Promoter solution II was made from dissolving tungstic acid (HC Starck, 99.99%) in DI water and cesium hydroxide in water (HC Starck, 50.42%) to achieve target Cs and W contents listed in Table 6. Promoter solution III was made from dissolving ammonium perrhenate (Engelhard, 99.4%) in DI water to achieve target Re content listed in Table 6. The combined solution containing silver complex solution, promoter solutions I, II, and III was stirred for 5 minutes. The combined solution was added onto the carrier J over 15 minutes under vacuum of 30 mbar. After addition of the combined solution, the rotary evaporator system was continued to rotate under vacuum for another 15 minutes. The impregnated carrier was then left in the apparatus at room temperature and atmospheric pressure for 1 hour and mixed gently every 15 minutes.

(28) TABLE-US-00006 TABLE 6 Catalyst name and amounts of ingredients used for preparation of catalysts 3.3.1 and 3.3.2. Catalyst 3.3.1 Catalyst 3.3.2 (comparative) (inventive) Carrier name Carrier J Carrier J Amount of carrier [g] 174.2 174.1 Amount of Ag-complex solution [g] 109.6222 109.5749 Ag-content in Ag-complex solution [wt %] 29.2 29.2 Amount of promoter solution I [g] 1.3768 1.3762 Li-/S-content in promoter solution I [wt %] 2.85/0.21 2.85/0.21 Amount of promoter solution II [g] 2.0651 2.0642 Cs-/W-content in promoter solution II [wt %] 4.8/2.0 6.0/2.0 Amount of promoter solution III [g] 3.2931 2.9705 Re-content in promoter solution III [wt %] 3.7 4.1

(29) Catalyst compositions are listed in Table 7.

(30) TABLE-US-00007 TABLE 7 Catalyst compositions (Ag-contents are reported in percent by weight of total catalyst, dopant values are reported in parts per million by weight of total catalyst) Example Carrier Ag [wt-%] Li [ppm] S [ppm] W [ppm] Cs [ppm] Re [ppm] 3.3.1 J 15.5 190 14 200 480 590 (comparative) 3.3.2 J 15.5 190 14 200 600 590 (inventive)

(31) TABLE-US-00008 TABLE 8 Key catalyst properties with respect to claims Carrier BET Catalyst Catalyst surface Carrier Carrier Carrier Carrier Cs- Re- Catalyst area C.sub.Si C.sub.Ca C.sub.Mg R1 content content R2 Catalyst Example [m.sup.2/g] [ppm] [ppm] [ppm] [mmol/kg] [ppm] [ppm] [mmol/kg] R3 3.3.1 1.06 700 300 100 13.32 480 590 0.443 0.039 (comparative) 3.3.2 1.06 700 300 100 13.32 600 590 1.346 0.120 (inventive)
4. Catalyst Testing I

(32) The epoxidation reaction was conducted in a vertically-placed test reactor constructed from stainless steel with an inner-diameter of 6 mm and a length of 2.2 m. The reactor was heated using hot oil contained in a heating mantel at a specified temperature. All temperatures below refer to the temperature of the hot oil. The reactor was filled to a height of 212 mm with inert steatite balls (1.0-1.6 mm), then packed to a height of 1100 mm with split catalyst (particle size 0.5-0.9 mm) and then again packed with an additional 707 mm inert steatite balls (1.0-1.6 mm). The inlet gas was introduced to the top of the reactor in a “once-through” operation mode.

(33) The inlet gas consisted of about 35 vol % ethylene, 7 vol % oxygen, 1 vol % CO.sub.2, and ethylene chloride (EC) moderation in the range from 1.5 to 3.5 parts per million by volume (ppmv), with methane used as a balance. The reactions were conducted at a pressure of about 15 bar and a GHSV of about 4800 h.sup.−1. For catalysts with an Ag content of >20 wt.-% (catalysts 3.2.2.1 to 3.2.2.22), the temperature and ethylene chloride (EC) moderation were adjusted such that a work rate of 280 kg(EO)/(m.sup.3(catalyst)×h) was obtained at the highest EO selectivity. For catalysts with an Ag content of <20 wt.-% (catalysts 3.3.1 and 3.3.2), the temperature and ethylene chloride (EC) moderation were adjusted such that a work rate of 250 kg(EO)/(m.sup.3(catalyst)×h) was obtained at the highest EO selectivity.

(34) Results of the catalyst tests with catalysts containing >20 wt.-% of Ag are shown in Table 9. The results show that the catalysts of the inventive Examples 3.2.2.3, 3.2.2.4, 3.2.2.5 and 3.2.2.6 have a significantly improved activity (measured as temperature to maintain the work rate) over the catalysts of the comparative Examples 3.2.2.2 and 3.2.2.15.

(35) TABLE-US-00009 TABLE 9 Test reaction results EO- Temperature Time on Catalyst Carrier Selectivity [%] [° C.] stream [d] 3.2.2.2 B 88.3 230.6 14 comparative 3.2.2.2 B 89.3 233.5 21 comparative 3.2.2.2 B 89.4 238.3 30 comparative 3.2.2.3 C 89.6 228.1 21 inventive 3.2.2.3 C 90.1 230.0 30 inventive 3.2.2.4 D 89.7 229.7 14 inventive 3.2.2.5 E 89.5 232.8 21 inventive 3.2.2.5 E 89.5 231.4 30 inventive 3.2.2.6 F 89.8 232.0 14 inventive 3.2.2.15 H 88.5 232.9 14 comparative 3.2.2.16 H 88.5 228.9 14 inventive

(36) Results of the catalyst tests with catalysts containing <20 wt.-% of Ag are shown in Table 10. The results show that the catalyst of the inventive Example 3.3.2 has a significantly improved activity (measured as temperature to maintain the work rate) over the catalysts of the comparative Examples 3.3.1.

(37) TABLE-US-00010 TABLE 10 Test reaction results for catalysts with Ag contents of <20 wt.-%. EO-Selectivity Temperature Time on Catalyst Carrier [%] [° C.] stream [d] 3.3.1 J 88.2 247.5 8 comparative 3.3.1 J 89.4 246.5 16 comparative 3.3.2 J 90.7 237.1 8 inventive 3.3.2 J 90.9 237.9 16 inventive
5. Catalyst Testing II

(38) The catalyst screening was performed in a 16-fold parallel reactor system. Every reactor was simultaneously supported with the same inlet gas, temperature and pressure.

(39) The used reactor tubes were composed of stainless steel (1.4841) and had a length of 290 mm with an outer diameter of 10 mm and an inner diameter of 4.5 mm. The isothermal zone of the reactor has a length of 70 mm and this was heated using an indirect electrical heating. 1 mL catalyst with a particle size of 250 μm to 300 μm was placed in the isothermal zone of the reactor tube.

(40) The filling concept of the reactor tube is described in table 11. The filling concept is a stacked bed with five individual zones. From reactor top to bottom the reactor filling consist of two inert stacks from steatite beads and silica particles, followed by the catalyst located in the isothermal zone in the center of the reactor tube, followed by another two inert stacks, consisting of silica particles and steatite beads. Zone 5 represents the top of the reactor tube, where the inlet gas was introduced into the reactor tube and conducted in once-through operation mode.

(41) TABLE-US-00011 TABLE 11 Reactor tube filling Height Particle size Zone [mm] Material [μm] 1  0-70 steatite beads 315-500 2 70-60 silica particles 200-300 3  90-153 catalyst 250-300 4 153-173 silica particles 200-300 5 173-290 steatite beads 315-500

(42) The experiments were carried out at a GHSV of 4850 h.sup.−1, a reactor pressure of 15 barg and a reactor temperature of 230° C. The inlet gas consists of 35 vol. % ethylene, 7 vol. % oxygen, 5 vol. % argon and ethyl chloride (EC), which was dosed over a range of 1.25 to 2.5 ppmv. Nitrogen was used as carrier gas and argon as internal standard gas.

(43) The reactor outlet gas was quenched with nitrogen at a ratio of 2:1 to 4:1 and was analyzed via online gas chromatography (GC).

(44) Tests were carried out at reactor temperatures of 230° C. and ethylene chloride concentrations of 1.25 ppmv and 2.5 ppmv. The results of the catalyst screening are shown in Table 12.

(45) TABLE-US-00012 TABLE 12 Test reaction results. Temperature EC EO yield Catalyst Carrier [° C.] [ppm] [%] 3.2.2.1 (comparative) A 230 2.5 6.23 3.2.2.7 (inventive) G 230 2.5 10.21 3.2.2.8 (inventive) G 230 2.5 9.82 3.2.2.9 (inventive) G 230 2.5 10.22 3.2.2.10 (comparative) G 230 2.5 7.58 3.2.2.11 (comparative) H 230 2.5 7.26 3.2.2.12 (comparative) H 230 2.5 6.83 3.2.2.13 (comparative) H 230 2.5 6.95 3.2.2.14 (inventive) H 230 2.5 9.16 3.2.2.17 (comparative) I 230 2.5 7.93 3.2.2.18 (inventive) I 230 2.5 9.92 3.2.2.19 (comparative) I 230 2.5 6.91 3.2.2.20 (comparative) I 230 2.5 7.36 3.2.2.21 (inventive) I 230 2.5 9.30 3.2.2.22 (comparative) I 230 2.5 6.13 3.2.2.1 (comparative) A 230 1.25 6.25 3.2.2.7 (inventive) G 230 1.25 10.74 3.2.2.8 inventive) G 230 1.25 10.48 3.2.2.9 (inventive) G 230 1.25 10.69 3.2.2.10 (comparative) G 230 1.25 7.38 3.2.2.11 (comparative) H 230 1.25 6.80 3.2.2.12 (comparative) H 230 1.25 6.00 3.2.2.13 (comparative) H 230 1.25 5.51 3.2.2.14 (inventive) H 230 1.25 9.71 3.2.2.17 (comparative) I 230 1.25 6.61 3.2.2.18 (inventive) I 230 1.25 9.38 3.2.2.19 (comparative) I 230 1.25 7.56 3.2.2.20 (comparative) I 230 1.25 5.14 3.2.2.21 (inventive) I 230 1.25 9.04 3.2.2.22 (comparative) I 230 1.25 6.67