DE3010533A1 - CATALYST COMPOSITIONS, THEIR PRODUCTION AND USE - Google Patents

Description

Dipl.-Ing. P. WIRTH Dr. V. SC H MIED-KO WARZIK I

DiPL-In ₉ -CDANNENBERG-Dr-P-WEINHOLD- Dr. D. GUDEL

335024 SIEGFRIEDSTRASSE

TELEPHONE: C089)

OG-I25439-I-G

Wd / Sh

Union Carbide Corporation

270, Park Avenue

New York, N.Y. 10017 / USA

Catalyst compositions, their preparation and use.

030040/0741

This invention relates to silver catalysts, their manufacture, and their use in the manufacture of Ethylene oxide. The catalysts of the invention include 5 a supported silver catalyst. The catalyst contains a combination of a) cesium and b) and at least one other Alkali metal from the group: lithium, sodium, potassium and rubidium, in which a) and b) in amounts (based on the amount of the silver contained therein) are available that are sufficient

10 in order to increase the efficiency of ethylene production to a value that exceeds the efficiencies that are below normal process conditions obtained with appropriate catalysts, which are similar to the said catalyst, however with the exception that instead of a) and b) one of the

ir, lysers the appropriate amount of a) and the other contains the corresponding amount of b). The catalyst as used in the manufacture of ethylene oxide contains i.e. a combination of cesium with one or more other alkali metals (excluding francium) in an amount

on which achieves a synergistic effect, as described here. In addition, da.5 methods of the invention indicate such synergism as a function of the silver content of the catalyst. For every amount of silver in the catalyst, the present invention creates the corresponding

_{? I} , corresponding ratio of alkali metal to silver, with special combinations of cesium with one or more alkali metals can be selected, which effect levels in the production of ethylene oxide, the higher level of efficiency that can be achieved with such a silver content

■ _m in combination with the appropriate amount of either

Cesium or another alkali metal obtained in such an amount.

The production of ethylene oxide by the reaction of oxygen ₃₅ fabric or oxygen-containing gases with ethylene in the presence of a silver catalyst is an old and well developed art. For example, USP 2,040,782 (1936) describes the production of ethylene oxide by reacting oxygen with ethylene in the presence of silver catalysts which contain certain metal promoters.

* = Effectiveness 030040/0741

In the US patent specification 20370 (1937) has been ^described,:: that the formation of olefin oxide may be effected ^by, olefins directly with molecular oxygen in the presence ^of: a silver catalyst can be combined. Since then, efforts in the art have been directed to improving catalyst efficiency in the manufacture of ethylene oxide.

¹⁰ BeL describing this invention, the terms

Conversion, selectivity, and yield used as described in the US patent 3,420,784 (1969) column 3, lines 24-35. The definition of selectivity agrees

i ^r> those respectively, as has been described in US Patent 2,766,261, Spate 6, lines 5-22 and U.S. Patent 3,144,916, Z. 58-6. 1 The definitions of "yield" and "conversion" have various meanings in the prior art, and these are not used as

? <> as defined in U.S. Patent 2,766,261, for example. The terms "Efficiency" and "selectivity" as used herein are intended to be taken as synonyms werdon.

, "> Silver catalysts used in the manufacture of ethylene oxide have undergone significant changes from the time of their first development period. According to the state the Tnoinik were initially silver particles on a carrier material deposited, with little attention paid to the carrier

ao properties, such as the surface, the Pore volume and the chemically inert behavior. As technology progressed, a special one developed Technology with regard to carriers that contain silver and that are used in the reaction of ethylene with oxygen

; is production of ethylene oxide were more effective. Exist today Most of the supports for silver catalysts made of finely divided substances with which the interior of the ffeactor can be loaded, so that the reaction gases and the gaseous products of the

Keissne patent,

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U IUOJJ

can flow around these particulate materials, where they flow through i through the reactor and be ^recovered: can. The shape of the supports is a variable factor, and the particular shape chosen will be adapted to the reactor used and the gas flow desired, the surface area desired, which is desired to optimize the reaction, also being coordinated with other factors.

The carriers used hitherto generally consist of inorganic substances and are generally more mineral Art. In most cases the preferred support is made of 'jC-alumina as described in the literature

_1S (see, e.g., U.S. Patents 2,294,383, 3,172,893, 3,332,887, 3,423,328, and 3,563,914).

The silver deposited on these carriers generally consists of small particles. It has been described in the literature that the size of the silver particles is a factor which determines the effectiveness of the catalyst. In most cases, is obtained silver fine particles using the standard procedures of the art, see for example US Patent 2,554,459, 2,831,870, 3,423,328 (there is described that silver particles are used of 150-400 R), US Patent 3 702 259 (describes a manufacturing process for forming silver particles less than 1 / µ in diameter) and US Pat. No. 3,758,418 (describes silver particles less than 1000 2 in diameter).

The deposition of silver on the support can be achieved by a wide variety of methods. The two on Frequently used methods are once the impregnation of the carrier with a silver solution with subsequent heat treatment of the impregnated carrier in order to achieve the deposition of the silver on the carrier, and on the other hand of the layering the support with silver by precipitating silver or the prior formation of silver in a slurry, such that the silver particles are deposited on the support;

0 300AO / 074 1

3 U Ί U b J J

T ⁷ T- ]

and adhere to the carrier surface when the carrier ί is heated to remove the liquid present. These various methods have been described in various US patents such as US patents _; 2,773,844, 3,207,700, 3,501,407 and 3,664,970 (see British Patent 754,593) and 3,172,893.

The surface value exhibited by the carrier was counter ■ was of great interest in the development of the silver J catalysts. Descriptions related to the surface value

the catalyst supports are contained in US patent specification

2,766,261 (which has a surface area of 0.002 - 10 m / g

US Pat. No. 3,172,893 (which describes a porosity of 35-65 % and a pore diameter of 80-200 / u), US Pat. No. 3,725,307 (which describes

a surface area of less than 1 m / g and an average Describes pore diameters of 10-15 / U), US Pat. No. 3,664,970 (according to which a carrier is used, which has a minimum porosity of about 30%, the pore diameter in the range of 1-30 / α with an average Value of about 4-10 / u) and US patent specification

3,563,914 (according to which a catalyst is used, the one

2 surface area of less than 1 m / g, a volume of

0.23 cem / g and a particle size between 0.074 and 0.30 mm Has).

In the earliest developments of silver catalysts for Production of ethylene oxide has been found to act as a number of metals in combination with silver Promoters for the silver catalyst can act. These substances are not themselves catalysts, but they do carry to increase the rate or amount of oxide produced. One of the problems with finding whether or not these metals act as promoters is the nature of the reaction itself. The reaction between oxygen and ethylene to form ethylene oxide is highly: exothermic. However, it is even more exothermic than this reaction

0 30 0 A0 / 0 7 A 1

the combustion of ethylene or ethylene oxide to carbon dioxide. These implementations occur simultaneously, and the ■ critical factor in determining the effectiveness of the ■. Overall procedure is the degree of regulation that one has with regard to these two competing reactions. It is therefore inevitable that a substance which promotes the production of ethylene oxide can at the same time also be regarded as a substance which enables the complete combustion of the ethy-10

lere or ethylene oxide to carbon dioxide prevented. The Pro ^:

The problem with the definition of the promoter is therefore whether this substance is not actually an inhibitor of the combustion reaction. It is known that there are substances there that when added to the reaction the formation of less

Cause carbon dioxide. Such substances are called inhibitors. There are also materials that are in attendance in addition to the catalyst cause a higher production rate of ethylene oxide, and such substances are used as promoters designated. Whether the latter substances actually inhibit

gates or promoters appears to be insignificant. What matters, is that the reaction result for the production of Ethy-; lenoxide is cheap. Therefore, when determining or Characterization of a catalytic process for the production of ethylene oxide the selectivity of the process an important factor to consider in the process with regard to the production of ethylene oxide.

The use of alkali metals as promoters in the silver catalyzed production of ethylene oxide is known in the art. Already in the US patent specification 2 177 361 (1939) the use of alkali metals in silver catalysts has been described. In the US patent It has been reported in 2,238,471 that lithium is very useful as a promoter, but that it is harmful to potassium and cesium be. In the examples of this patent are essentially 10 wt .-% potassium hydroxide or cesium hydroxide; with the silver oxide used in the manufacture of the catalyst;

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ORIGINAL INSPECTED

used. It was later described in US Pat. No. 2,404,438 that sodium and lithium were effective promoters ren are for this reaction. Much the same thing has been described in US Pat. No. 2,424,084. J U.S. Patent 2,424,086 generally gives alkali metals as

Promoters and mentions sodium in particular. According to the US; Patent 2,671,764 was believed that alkali metals are effective in \ io form of their sulfates as Pomotoren for such silver catalysts. In particular, it has been described that sodium, potassium, lithium, rubidium or cesium sulfates can be used as promoters. In the US

Patent specification 2,765,283 describes a pretreatment of a support with a dilute solution of a chlorine-containing compound, wherein such a chlorine compound should be inorganic. Specific examples of suitable inorganic chlorine compounds include sodium chloride, lithium chloride and potassium chlorate. In this patent it has been stated that the amount of the inorganic chlorine-containing compound which is deposited on the supported catalyst; from 0.0001-0.2% by weight based on the weight of the carrier ^. US Pat. No. 2,615,900 describes the use of metal halide in the treatment of supported catalysts, such halides being alkali halides such as ζ "Β. ; of lithium, sodium, potassium and cesium. The metal halide is present in an amount of about 0.01% -50% based on the weight of the metallic silver. In this patent it is also described that there are pre-; _{30 is} part of using mixtures of the individual metal halides described in the patent: ι, namely there-; going to increase the so-called "break-in" period of the new Kata-, lysatorverbindungen, whereby at the same time a; average but steady stability of the catalyst over a period of time; _3I . extended period of time during normal operation; ί was maintained. So there would be certain, with metal · * ·

Catalysts treated with halides have a short-term, high initial activity, while other metal halide! nide to impart long-term, mediocre activity to the catalyst.) This patent is of the opinion ^

INSPECTED

that the metal halides which are present in the catalyst, serve to prevent the combustion of ethylene to carbon dioxide 5, so that these substances act as catalyst-inhibiting or anti-catalytic substances are classified. US Pat. No. 2,709,173 discloses the use of a silver catalyst for the production of ethylene oxide has been described, j being simultaneously with the application of the silver catalyst jio on or in the solid support of one of the following alkali ! metal halides, such as lithium, sodium, : Potassium and rubidium compounds of chlorine, bromine and iodine, to increase the overall production rate of ethylene oxide. ! The patent states small amounts of "less than about! 15 0.5% as useful". In particular, in the patent "Proportions of alkali metal halides between about

i 0.0001 to about 0.1% "as particularly preferred

- lifted. The patent indicates that

; "although the preferred catalyst composition has a

- Contains 20 separate promoters, this is not always necessary

• because during the production of the catalyst the alkali metal

j halide to some extent to the corresponding

\ Alkali metal oxide is converted, which acts as a promoter

. \ Acts "US Patent 2,766,261 appears from the _teaching;

= 25 of US Pat. No. 2,238,474 to deduce that cesium and}

- potassium in silver catalysts are harmful, while sodium \ and lithium are suggested as useful promoters.

'However, in US Pat. No. 2,769,016 it has been found that ■

> That sodium, potassium and lithium act as promoters, if

| ₃₀ they are used in silver catalysts. This latter

The patent also recommends pretreating the support with dilute solutions of sodium chloride, lithium chloride, or potassium chloride. It is stated in U.S. Patent 2,799,687. I that the addition of metal halides within the range described in the I ₃₅ US Patent 2,615,900 to any extent

leads to optimal results. This, it is said, is especially true in the case of alkali metal halides, especially the j chloride and fluoride of sodium and potassium. It is recommended that the inorganic halide component of the

030040/0741

ORIGINAL INSPECTED

- · ΛΙ

Catalyst in the range of 0.01-5% by weight, preferably 0.01-0.1% by weight, based on the weight of the "the oxidation;> ⁵ catalyzing silver component", ie the silver salt that | j converted to elemental silver is held. \ ! US Patent 3,144,416 mentions a variety of metals' as promoters, one of which is cesium _o In the US patent 3,258,433 has been described that sodium is an effective promoter j. US Patent 3,563,913 recommends the use of alkali metals, such as lithium compounds, as promoters. The preferred amount of the promoter is from about 0.03 -0.5 wt .-% of metal, based on the weight of the carrier specified by \. In U.S. Patent 3,585,217! have described that alkali chlorides "are known to counteract the formation of carbon dioxide" and "can be incorporated into the catalyst". US Pat. No. 3,125,538 describes a supported silver catalyst; a simultaneously deposited alkali metal from the group of potassium, rubidium and cesium in a special gram-atom- ^; Ratio, based on the silver, contains. The weight of the silver is preferably 2-5% by weight of the catalyst. This catalyst is said to be particularly suitable for reacting nitrogen dioxide with propylene; US Pat. Nos. 3,962,136 and 4,012,425 describe the identical catalyst as being effective in the production of ethylene oxide. In US Pat. No. 3,962,136 the simultaneous deposition of alkali metal and silver on the support has been described, the alkali metal in its final form on the; 30 carrier is present, in the form of a cesium oxide, rubidium oxide or mixtures of these, optionally in combination with a smaller amount of potassium oxide. The amount

of such an oxide is about 4.0 10 ~ wt / kg to about

3 ■

: 8.0 10 wt / kg of the total catalyst. US patent specification

^; 35 4 010 115 differs from this teaching, however, since it uses potassium oxide as the alkali metal oxide, optionally in combination with a small amount of rubidium or cesium oxide. U.S. Patent Application 317,349 (1972) to which

'. the patents 3,962,136 and k 010 115 and others back-j

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3010633

contains some interesting data that should be considered. In Example 2, which contains some comparative experiments ^, the production of a catalyst is described, the ί 310 parts by weight of simultaneously added potassium ent-; holds. It was found that this catalyst was inactive when used as an ethylene oxidation catalyst or for the production of ethylene oxide. Although this amount of potassium
in this catalyst within that in the US patent; 4,010,115 as effective for the production of ethylene oxide
is the range described, no values are given in the patent to support this view.

In Belgian Patent 821,439, based on the ^British: see patent 1489335 is based, it has been described that a catalyst can be prepared in accordance with the
U.S. Patents 3,962,136, 4,012,425 and 4,010,115
Catalysts produced is equivalent by
the method by which the alkali metal
is applied to the carrier. According to the Belgian patent specification or the corresponding British patent specification
becomes a porous, heat-resistant carrier with a certain
Surface value first impregnated with an alkali metal,
in order to deposit this on the carrier material in certain amounts (both the amount and the type of porous
Carrier correspond to the above-mentioned US patent
4 010 115). Then the carrier is dried to fix the alkali metal and then the silver is applied to the
Carrier applied. This procedure gives a

subsequent deposition of the alkali metal promoter and
of the silver catalyst. Apparently, one is essentially
Similar type of catalyst due to simultaneous deposition
made of alkali metal and silver, as a \ comparison of the values in the example of Patent beigischen;

font with the data of the aforementioned patent specification 4 010 shows. The critical importance of the deposition process the presence of alkali metal on the support appears doubtful; consider ι

0300A0 / 0741

of this patent specification and patents 4 033 903 and I 4 125 480, which describe the treatment of a used silver j containing catalyst by a subsequent supply of a j

i

■ or more of the metals potassium, rubidium or cesium; beschreiben.Eine such treatment apparently places the '■ catalyst in the location, the selectivity to ethylene oxide

j to reinforce. US patent 4,066,575 is a further ^(j ίο patent, is described in that subsequent, supply of alkali metal such as cesium, provides results, 'which both the previous and the simultaneous _supply;

are equivalent.

■ is US Patent 3,962,136 has related patents based on US patent application 216 188 (1972) ', which-

: se. US patent describes that "the highest level of selectivity that can be obtained with potassium-modified catalysts all other things being equal, normally

■ ? O is less than that which one with rubidium or cesium

\ modified catalysts obtained (see column 2, lines 38-42) ', US patent application 216 188 includes a drawing which shows the relative effectiveness of rubidium, cesium and potassium in enhancing the selectivity of ethylene oxide when

■? 5 these can be used in a silver catalyst. The drawing ^! tion shows that curve C, which represents the addition of cesium, J gives the greatest increase in selectivity, while curve B, which represents the addition of rubidium, shows mediocre values; which, however, are superior to the addition of potassium, represented by curve A. In a pamphlet filed on April 11, 1975; Sentence in US patent application 480 896, on which US patent application 4 010 115 is based, the applicant emphasizes that.

Description and claims no "synergistic effects.

due to the use of "mixtures" of alkali metals. The same statement is in the entry;

dated April 11, 1975 in U.S. Patent Application 471,398 (1974) ^: j on which U.S. Patent 4,012,425 is based. i

·

030040/0741 ORIGINAL INSPECTED

3010b33

-ns-

In Denj examples, the German Offenlegungsschrift 26 40 540 describes a silver catalyst for Sthylenoxidherstellung, 5 of the sodium and either potassium, rubidium or cesium corresponds ■ holds. In Table I of this publication, the! ! Alkali content of all kata prepared according to the examples ^! i lyzers have been shown, many of which contain sodium, potassium, and cesium. In a footnote to the table it is stated that i ₁₀ that the presence of potassium in all of the catalysts examined; (except for one that was cesium-free) is based on impurities in the carrier, the extent of such impurities being below that which is said to be useful in accordance with the invention. The laid-open specification does not suggest 1 ₁₅ that cesium can advantageously be combined with potassium and / or sodium; could be ned, the efficacy data still show! in the table a synergistic effectiveness of cesium ί with sodium or the potassium impurities in the catalyst

■ goal.

! Japanese patent application 95 213/75 relates to

; a method for producing ethylene oxide using a catalyst composition that converts silver, barium, potassium and cesium in certain atomic proportions

; grasps. In Table I of this application, the effectiveness values are summarized, which one after the examples with the various

; obtained different catalyst compositions. None of the cesium-potassium-barium mixtures in the examples showed any synergistic effect. A comparison of some examples in

Indeed, Table I shows the absence of one

Cesium-potassium synergism, because that is the effect that one

I with a cesium-potassium mixture has been shown to be lower than that obtained with the same amount

; Preserves cesium in the absence of potassium. Examples 3 and

; 7 e.g. refer to catalysts with an identical atomic ratio of cesium to silver (0.05 atoms / 100 atoms

j Ag), but with a different potassium content, whereby the:

■ Atomic ratio of potassium to silver in example 3 = 0.001 atoms K / 100 atoms Ag and the corresponding ratio in both

of cesium and potassium

030040/0741

BATH ORIGINAL

3010553

! game 7 = 0.05. The effectiveness obtained according to Example 3 i is 76.4% and that according to Example 7 is 75.9%. I j 5 The greater potassium content in Example 7 thus had one; Decrease in catalyst effectiveness as a result. In a similar ·; ' Examples 1 and 4 relate to catalysts ^! with an identical atomic ratio of cesium to silver, the catalyst according to Example 1 containing an amount of potassium which is one order of magnitude higher than in Example 4. Nevertheless, the stated catalyst efficiency is essentially the same, namely 76.7% in Example 1 or 76.6% in example 4.

A o39 561
In the US patent, a catalyst for the production of ethylene oxide has been described which contains silver, tin, antimony, thallium, potassium, cesium and oxygen in certain atomic proportions. Mixtures of cesium and potassium have not been mentioned as a desirable combination. In Table I of this patent a silver-cesium-potassium combination is described which is described as a comparative example and as not in accordance with the invention. A selectivity of 73.0 % is thus achieved, a value which is significantly lower than the selectivity of the 45 examples which have been shown in Tables 2 and 3. Furthermore, the efficacy values of the various catalysts shown in Tables 2 and 3 do not show a synergistic combination of cesium and potassium among the various combinations of elements used in the catalysts. It is also remarkable

30 ^y

It is worth noting that the aforementioned US Pat. No. 4,039,561 claims priority of a Japanese application from 1973 and that thereafter the same applicant claims the Japanese Patent application 25 703/77 has filed, which describes a catalyst for Ä'thylenoxidbildung that the same metal elements - as described in the US patent - includes, with the exception of cesium and potassium. The efficacy values shown in the examples of the latter Japanese application are the same as those of FIG

^; 0300AO / 07A1

301Q533

US patent specification. The effect of cesium and potassium in the catalyst composition according to US Pat. No. 5 is therefore probably insignificant.

j In the Belgian patent specification 854 90A silver catalysts have been described, the different mixtures; Contains sodium and cesium. In British patent application 2 002 252 A, a supported silver catalyst is given in Table II which contains various mixtures of cesium and thallium, some of which additionally contain potassium or antimonium. The US patent! 4 007 135 relates generally (column 2, lines 25-30) to: ₁₅ silver catalysts for the production of alkylene oxide, the silver

"together with a catalytic amount of at least one \ promoter from the group lithium, potassium, sodium, rubidium,; cesium, copper, gold, magnesium, zinc, cadmium, strontium, calcium, niobium, tantalum, molybdenum, tungsten, chromium, vanadium 20 ^{un (} 3 barium "contain. The European patent application; with the publication number 0003 642 describes in table; III silver-containing catalysts which comprise mixtures of potassium and cesium and a catalyst which contains sodium and cesium. The cited publications show none. _{? ()} synergistic interaction of cesium with other alkali metals.

In the Belgian patent 867 045 supported silver catalysts have been described which have a so-called effective \ ₃₀ seed proportion of lithium and a significantly lower; Amount of alkali metal from the group consisting of cesium, rubidium and / or potassium. In Table I of this patent three catalysts have been described that contain all of the cesium, sodium, potassium and lithium, wherein the lithium concentration = _'35 at least an order of magnitude higher than is: the concentration of cesium or potassium. The mentioned in Table I \ catalysts L1, L2 and L3 include very comparable: different concentrations of cesium, potassium and sodium, j in Table II, however, is stated to be essential in the same loan ■ selectivity effect. It's not a clue

030 040/0741

■ Al

to a synergistic interaction of cesium with potassium! or added sodium to the silver catalysts.

j The Belgian patent specification 867 185 describes silver carriers! catalysts for Äthylenoxidherstellung that a certain \ amount of potassium and at least another alkali metal selected from the group containing rubidium or cesium. Table I shows the compositions of 14 potassium-containing catalysts,

2 of which contain potassium in combination with cesium (catalysts G and H). The selectivity of the catalysts G and H is found to be identical at a pressure of 1.03 bar . shown, but is slightly different at a higher Mb pressure of 16.55 bar. No silver-potassium-cesium synergism can be seen from the values.

The present invention differs from the prior art in the fact that the ' '? o Ethylene oxide used silver catalyst at least 2 alkali metals used (excluding francium), one of which is cesium, each of the alkali metals in such Amount is present that their combination is synergistic with respect to the amount of silver in the catalyst Effect with regard to the ethylene oxide selectivity creates a selectivity that is greater than any previously after Prior art achieved selectivity.

The method according to the invention and the method according to the invention. 3o catalyst are characterized by a combination of; a) cesium and b) at least one alkali metal from the; Group: lithium, sodium, potassium and rubidium, in order to achieve a synergistic effect, ie an effectiveness that is greater than the greatest value that is obtained under the usual - ■ 3 _S conditions with appropriate catalysts that match the; same catalyst, but with the exception

that the one - instead of a combination of a) and b) - '! contains only the corresponding amount of a) and the other only the> corresponding amount of b). The \

_{3 0 040/0} 7 A 1 mmpL

Catalysts include silver, cesium and at least one other alkali metal (excluding francium), which are on a] Surface of a porous support are deposited. Here lies in the special mixture of silver and alkali metal j

j such a relation, ate a synergistic effect

, is called.

ι ¹ O In the following description, the binary alkali »metal combination is one of cesium-lithium, cesium-sodium, cesium-potassium and cesium-rubidium, which in combination; nation with silver has a synergistic effect on certain! Supported catalysts and certain catalyst compositions ^! 15 genes. The catalysts of the invention are

but not restricted to binary combinations of alkali metals. The addition of other alkali metals to any of the aforementioned binary combinations can have beneficial effects in terms of raising or lowering the cold analyzer process temperature, improving the initial catalyst activity during the initial period and / or improving the aging properties of the catalyst over a longer process period. In some cases the addition of a third or even fourth alkali metal to an already synergistic binary combination has the effect ^; a further increase in catalyst efficiency.

The mathematical relationships that differ from the inventive Deriving synergistic, binary alkali metal combinations are explained below in relation to Cesium-potassium combinations shown. . Binary combinations of cesium with any other alkali metal according to the invention can easily be derived in an analogous manner, with the alkali of interest in each case

35 metal instead of potassium in the case of the one mentioned below Procedure is used.

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The ratio of cesium, potassium and silver to achieve the synergistic effect described here can be achieved with the help of a mathematical equation or a model can be represented, which the effectiveness as a function of the proportion of syllable «·,

• Cesium and potassium (each in% by weight) on the catalyst has been deposited in relation to the carrier. A synergism with mixtures of cesium and potassium can achieved with any concentration of silver in the finished catalyst will.

The general form of the mathematical equation that follows-;

hereinafter referred to as the "efficacy model" defines j

₁₅ the effectiveness (or selectivity) as a function of I.

Percentages by weight of silver, cesium and potassium on the j

Carriers were deposited as follows:!

i effectiveness % = ^ +

+ ^b 9 2 + b ₅ (BCs) (BG χ j (BK) ² + (BG χ BCs) ^{+ b} 8 BK) + (BCs χ BK)

ί where b to b _{q are} the respective coefficients for each term! of the effectiveness model mean and represent a number of the constants ί ί ■ that for a specific catalyst support and a

ί specific process of catalyst production after a:

"" Series of experiments as described below were determined.!

The value of some of these coefficients can be zero. i

BG = (wt% Ag - wt% Ag ") ί

where wt .-% Ag = the average value of wt .-% Ag, the I.

is used in the series of experiments. !

BCs = (wt% Cs - wt% "Cs")

where wt% Cs = the average value of wt% Cs that '■

is used in the series of experiments. j

BK = (Ge_w _.-% K - wt .-% T),! where% by weight K = the average value of% by weight K used in the series of experiments.

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The set of experiments is best designed in the form of a "composite design" with three independent variables, like this by Davies in "The Design and Analysis of Industrxal Experi-." ments ", Hafner Publishing Company, 1960, pp. 532-535 has been. The three independent variables here are:% by weight of silver, cesium and potassium. The range of each variable was chosen to suit the selectivity and activity of the Catalysts can be measured in the specified series of experiments under the desired test conditions. It is It is therefore advisable to first carry out a few preliminary tests in order to provisionally determine the corresponding ranges for cesium and potassium to determine. Zero percent cesium and / or potassium is a convenient lower limit for use in that "Composite Design". The upper limit of the concentration for

\ Cesium and potassium can be made through a number of experiments

can easily be determined with the catalysts gradually increasing amounts of either cesium or potassium as follows

• _{Contain 20} : A starting catalyst is produced (if necessary according to the examples given in the following

; Preparation method), which contains a small amount (in the order of about 0.001 wt .-%) of either cesium or potassium and a fixed amount (for example 7 wt .-%) of _{silver,? B} Then, the selectivity in the production of Ethylene

\ oxide determined under the desired test conditions. This experiment is then repeated with a catalyst which contains twice the amount (0.002% by weight) of alkali metal,

; and the experiment is repeated within a series of experiments, each subsequent experiment using a catalyst having twice the alkali content than that

; Catalyst of the previous experiment until the measured Selectivity of the last tested catalyst lower

j is than that of the initial catalyst. The upper limit of the cesium * j or potassium concentration is on this basis for the "composite"

j design ".

\ The procedure described above can advantageously be changed

', are used to determine the upper limit of the concentration more quickly in the event that a twofold increase in;

0300A0 / 0741

- te--

Alkali metal content in the catalyst does not significantly change

tion of the catalyst selectivity provides. This can be e.g. j

especially with catalysts containing lithium or sodium

hold (depending on the specific carrier and the s

applied manufacturing process) occur in contrast j

to catalysts containing other alkali metals, where i - as a general rule - the _resulting change in effectiveness is greater with increasing alkali concentration.

. So in the event that the catalyst effectiveness is practical

; remains unchanged, even if the alkali content of the catalyst has been doubled, should be described above; A tenfold alkali content was used for the same repetition ^!

until the measured effectiveness of the last catalyst is less than that of the initial catalyst. Then it can be useful ^{to repeat the last repeating step:} with a lower alkali content, such as

Halts to the upper limit of the alkali metal concentration for the "Composite Design" to determine more ^precisely: ■ a three- or five-fold increase in the Alkalimetalle-. ^r

The range of silver concentration in the "composite design". can normally be 6-16 wt% with the average value of silver (wt% Tg) being 11 wt%. Similarly, the ranges of cesium and potassium concentrations are typically from 0.0 to 0.02 weight percent. For rubidium, the range is suitably from 0.0-0.02% by weight, while the range for lithium and sodium is normally 0.0-0.1% by weight. For some carriers, the upper

limit the concentration of cesium and / or potassium to be 5-10 times greater. This can be the case especially with carriers

■ that contain exchangeable cations.

> In table 11.5 (page 533) of the aforementioned publication

Davies describes a "composite design" with three variables, which is divided into units of -pC »-1, 0, +1 and + cC , where -1 is a" low degree "of the corresponding variable and +1 a "high degree" of such a variable

030040/0741

and ○ denotes the average degree of the variable. -tC
is a degree slightly below that of -1 in value.

draws a degree that is slightly higher than the value represented by +1. The respective choice of - <£ and + <C is not ' ^: decisive. Table 11.6 on p. 534 of the Davies publication, however, suggests values of - <C and + cC, which are particularly useful for a "composite design"

and are also particularly useful according to the invention. The ex-; period series thus typically comprises 16 to 20 experiments, in which catalysts with different concentrations tested on silver, cesium and potassium. A prefer-! tes "composite design", in which e.g. the silver content in the

The range is from 7.0 to 15.0% by weight, the proportion of cesium in the range rich from 0.0 - 0.02% by weight and the potassium content in the range ' from 0.0 - 0.01% by weight is as follows:. .

Wt% silver

20 g

13th

9 13

9 13

25 13

11

11

15th

! 11

i. 11

i 11

! so 11

Weight percent cesium Wt% potassium 0.005 0.002 0.005 0.002 0.015 0.002 0.015 ■ \ "£ -; 0.002 0.005 ^; · / :. 0.008 0.005 "'■■ * 0.008 0.015 '·' «■ · 0.008 0.015 0.008 0.010 0.005 0.010 0.005 0.010 0.005 0.010 · * ■ 0.005 0.0 0.005. 0.020 . . .0.005 0.010 , r ■ '"■ 0.0 0.010 0.010
■ i "
* u - -

The catalysts of the experiment series Who dear, known to help, \ according to the prior art Ve.rjfkhfierf Jfur measure

Selectivity and Activity Investigated .-- An * appropriate level

for the activity, ie the rate of conversion of. Reaction ^ - · _; The participant in the product per unit of time is the temperature, which is required either to achieve a certain ethylene oxide production value or a selected conversion i

~ - J ₁ - U- '■

030040/0741 Ί ': ■ *

-. '*' BAD ORIGINAL

value of mol% ethylene (or oxygen) to be obtained. One
mathematical equation for the catalyst temperature (temperature; 5 temperature model) can be used in a manner similar to the efficiency

Model to be developed. This means that for each catalyst i two results are obtained (selectivity and temperature); ι which are dependent on the three variables (wt .-%
I in silver, cesium and potassium). The dependency between:: ', ο every result and the regulated variable is obtained by: I converting this data into an equation or a mathematical one? j model uses the least squares method, as in Example 8 of "Statistical Methods in ij Research and Production" by OL Davies and PL Goldsmith, > J ₁₅ Longman Group, Ltd., London, 4th edition, 1976 , described | ^; has been. In practice, adjusting a mathemati:! view such data routinely with the help of a model

Digital computer, as described in "Applied Regression · Analysis "by N.R. Draper and H. Smith, John Wiley and Sons, '

_'20 Inc., 1966. The models thus obtained; ΐ (the effectiveness model and the temperature model) describe = • the relationships between the results and the regulated ^

Variables.

j It is known that the number of experiments required for setting up mathematical relations between different
: Variables required by the reproducibility of these _:

Data depends. For a "composite design" that includes around 16 experiments, it may occasionally be necessary
j all or part of the series of specified experiments ·, j to repeat to establish the relation between effectiveness and
! Weight percentage of silver, cesium and potassium on an _ac-: define statistical credibility j zeptables measure. In practice it has been found that for a series of about 16 experiments, in which the percentages by weight of silver \

35 - ^T

of about 7% - 15% vary, a complete re t HOLUNG of the experiments is usually sufficient to hang the cooperation 'to find ^ under the Vorraui estimation that the standard

030040/0741

ORiGIiMAL INSPECTED

deviation of a single attempt no greater than 0.7%
in units of effectiveness. In the course of the experiments \

5 also other values besides those of the above experimental ^; series can be collected, which is useful for setting up the model described above. For example, values from the aforementioned preliminary tests to find the limit ranges as well as
other, additional test data relating to a

special supported catalyst and manufacturing processes are available, expediently with those from the "composite Design "can be combined and the equation is fitted to this data. Consequently, in practice Data from around 30-60 experiments to develop the efficacy and temperature models will be available.

The general form of the mathematical equation, hereinafter referred to as the "temperature model", defines temperature as a function of weight percentages of
₂₀ silver, cesium and potassium on the catalyst support
are deposited as follows:

Temperature, ⁰ C = · ₀ + «]. (BG) + * 2 (BCs) + · ₃ (ΒΚ)

+ a ₅ (BCs) ² + · ₆ (ΒΚ) ² + «7 (BCs χ BG) + a ₈ (BG χ BK) + a ₉ (BCs χ BK;

where a - a _{g are} the respective coefficients for each term in the temperature model, comprising a number of constants; 3o that are applicable to a particular carrier and a particular! Method of catalyst preparation according to the experiments' ■ ment series, are determined as described above. The value j of some of these coefficients can be zero. BG, BCs and BK have been defined above.

The most appropriate use of the effectiveness and temperature models to determine the synergistic range for each selected weight percent silver in the Catalyst is the representation of the effectiveness and temperature

0300A0 / 07A1

rature result in graphical form, which is generally called
"Contour maps" is referred to as the example 11 of the aforementioned publication "Design and Analysis of Industrial Experiments" has been described. Figu-j ren 1 and 2 show the contour lines. Maps of the effectiveness and j temperature for a selected carrier and a selected ^! Catalyst production process with 7 or 13 wt .-% silver .. io The contour maps were from a specified series f; obtained in experiments, the silver content in the range j: from 5.88 - 16.05%, the cesium content from 0.00 - 0.019%

and the potassium content was in the range of 0.00-0.021%. The ! Table I below summarizes the test data that were used for | the selected support and the catalyst preparation method ^; driving were available and of which the contour line maps
were derived. The trials were in two different ways; Test reactors carried out according to the standard test procedure which is described below under the heading "Catalyst: compare". Two similar, only ί slightly different carriers were used in experiments I. Table I shows the experimental data in a more general way; Basis, ie the data were matched to established
To compensate for differences between the reactors used and the Kata-2f, lyser carriers.

Ö30040 / 0 74 1

Wt% silver

Tabel

% By weight% by weight temperature effectiveness cesium potassium in C in %

11.14 0.00477 0.0015B 10.53 0.00897 0.0 11.14 0.00479 0.0 11.01 0.00941 0.00312 11.21 0.00240 0.00080 10.92 0.01865 0.0 11.OA 0.00941 0.0 04/11 0.00941 0.0 11.09 0.01421 0.00412 10.41 0.0 0.0 10.41 0.0 0.0 11.16 0.01909 0.00633 10.94 0.01403 0.0 10.70 0.01128 0.00379 9.08 0.01900 0.00315 9.31 0.00968 0.00645 13.17 0.00617 0.00102 9.10 0.00323 0.00214 13.14 0.00915 0.00613 11.11 0.00950 0.00315 11.31 0.01206 0.0 05/11 0.00236 0.00078 12.72 0.00311 0.00207 16.05. 0.00941 0.00313 5.88 0.00924 0.00306 04/11 0.01421 0.00157 10.89 0.00462 0.00450 10.80 0.0 0.00613 t.93 0.00630 0.00105 15.51 0.01218 0.0 «.03 0.01341 0.0

11/13

0.00897

0.00810 256.0 256.4 256.0 256.0 258.0 282.2 257.2 255.0 270.7

263.0

265.0

292.6

267.0

262.0

293.0

269.9

254.9

260.0-

259.1

259.6

260.3

260.4

255.8

263.0

269.1

268.9

256.4

260.5

260.4

266.4

280.3

266.2

73.9 77.5 72.9 77.4 70.7 74.3 76.3 76.3 75.7

68.5 66. *.

72.0 76.7 77.5 71.8 76.6 74.2 72.7 77.5 77.6 77.4 70.1 71.6 77.7 76.8 76.7 75.4 69.9 74.4 77.2 73.7

77.1

T3 0040/0741

ι 20th - d * -
Continuation of table I: Wt%
Cesium Wt%
potassium ■ kl · temperature
in ⁰ C 3010533 Ί
: Wt%
silver 0.00888 0.00800 264.3 16.00 0.0 0.01230 263.6 effectiveness
in % : 5 10.93 0.01562 0.00469 277.1 77.8 12.95 0.01313 0.00386 268.1 73.3 !
I. 25th 13.12 0.00150 0.0 264.4 76.0 12.85 0.01047 0.00297 257.3 77.0 13.12 0.01784 0.00540 282.3 66.2 10 13.26 0.01384 0.00407 269.4 78.3 « 12.91 0.01384 0.00407 269.8 74.5 12.91 0.01038 0.00295 257.0 77.0 ί 12.91 0.01038 0.00295 257.2 77.2 ; 12.91 .0.00150 0.02100 299.0 76.3 i 15th 13.00 0.01038 0.01500 290.7 76. i 13.00 0.00150 0.01470 268.6 67. C i 6.68 0.01056 0.01220 269.2 72.2 ϊ
; 7.14 0.00594 0.01010 280.4 73.7 ϊ
ί 7.06 0.00727 0.00192 263.3 72.3 I.
i 6:00 am 0.01153 0.00330 274.4 75.2 8.00 0.01171 0.00339 272.7 75.7 8.15 0.00749 0.00199 262.2 76.9 8.30 0.00150 0.0 268.0 77.6 8.03 0.01056 0.0 264.0 76.5 7:00 0.01056 0.00400 271.0 69.0 7:00 75.5 76.2

030040/0741

-Xl

The specific efficacy and temperature models that vo the aforementioned data were derived using the least-5-square method mentioned, are as follows: j

Efficacy,% = _{77 19 +} 0.196 (BG) + 133.4 (BC «) i

+ 120.5 (BK) - 63787.0 (BCs) ² ι

- 47229.0 (BK) ² + 52.1 (BG χ BCs) ;

10 ^:

- 60823.0 (BCs χ BK); and

Temperature, ⁰ C = 259.44 - 1..279 (BG) + 1555.8 (BCs)

+ 794.1 (BK) + 0.3466 (BG) ² + 168544.0 (BCs) 2 ₊ 147856.0 (BK) ² + 132807.0 (BCs χ BK)

I -

ι where BG = (wt .-% Ag - 11.0)
j BCsr (wt% Cs 0.01)

■ BK (% by weight K 0.003)
j mean ^25.

■ Figures 1 and 2 show contour lines of constant effective ! speed and temperature with variable potassium-cesium concentration

• actions. The darker lines indicate the contour lines of the

; ³⁰ selectivity, where the selectivity value for each line

! is specified. The lighter dashed lines represent the

I shows the temperature contour lines in ten-degree steps.

\ The effectiveness and temperature for points between the other

j given contour lines can be interpolated.

i35 times selectivity that you get from every possible combination

; of cesium and potassium as a function of the cesium concentration

! tration is obtained by the designated "Sel _M "

j curve shown. This curve represents the maximum synergism. mus that is possible for any given fraction of cesium. \

¹ "0 3 0 0 40/0 741

The synergism curve (referred to as "A" in Figures 1 and 2) separates the area of synergism, as described herein, from the areas of additive and antagonistic effects.

Additive effects occur when the effectiveness achieved with a combination of cesium and potassium is an average j of the effectiveness values obtained under normal conditions with catalysts similar to the catalyst containing said combination, with the exception that an - \ site of potassium and cesium of a catalyst, only the j corresponding amount of cesium and the other contains only the corresponding amount * de potassium. Antagonistic effects occur '

j on if the effect you get with a mixture of cesium!

I ₁₅ and potassium obtained is lower than the effectiveness values \ obtained with corresponding catalysts, which in each case; only the corresponding amount of cesium or the corresponding;

. Amount of potassium contained alone, as described above ) \ . The area defined by the ordinate, the abscissa and \ ! _{? 0} the synergism curve (curve "A) is limited, describes the?

; synergistic surface according to the invention. The area on the right j! next to the synergism curve "A" represents the area of the additive dn

and antagonistic effects - as described above - represent '<', ie it denotes mixtures which are not in accordance with the present invention. The preferred combinations of cesium and potassium on the contour lines are those which have selectivity values on the " ^Sel Max" curve or near the "Sei .." curve. In general, preferred mixtures are those in which cesium and ^! , Potassium are present in a weight ratio of about 100: 1 to 1: 100, each depending on the particular Kata-; lyser carrier and the chosen manufacturing process. Preferred mixtures of cesium and lithium or cesium and; Sodium are usually those in which the alkali metals in ^ä a weight ratio of about 1000: 1 to 1: 1000. forward '.

According to FIG. 1, a catalyst containing, for example, 0.003% cesium and; Contains 0% potassium, about 73 % effectiveness. The addition;

030040/0741

- «34 ·

from about 0.008% potassium to this catalyst results in an increase in the effectiveness to about 76.0%, ie the maximum selectivity with this proportion of cesium (value on the "Sel _M " curve). A further addition of potassium up to about 0.016 % (that is the value on curve "A") would result in effectiveness values which are equal to or greater than those obtained with the specified amount (0.003%) of cesium alone

ίο (i.e. when no alkali metal other than cesium is present). Adding more than 0.016% potassium results in efficacy values that are lower than those obtained with It contains 0.003% cesium alone, i.e. it is in the area of additive or antagonistic effects. Still can

15 such an amount of potassium that such antagonistic effects causes a catalyst with a quite appropriate selectivity and activity for a particular procedure result.

The synergistic range changes depending on the silver content of the catalyst, as can be seen from the efficiency model ^f . Figure 2 shows the region of synergism at 13%> silver. The "Be," curve and the synergistic curve; (Curve "A") of FIG. 2 correspond to those of the description of FIG. 1. Comparisons of FIGS. 1 and 2 show that the j contour lines of effectiveness are similar to one another, however; are different with respect to the cesium and potassium axes. For example, j encloses the line for a 76% effectiveness in FIG. 1, an area which is smaller than the area delimited by the corresponding line in FIG. The maximum value of the selectivity that is obtained γ% by weight of silver, ie the maximum on the “Sel _Max ” line, is also somewhat above; 76% (Figure 1), while the corresponding maximum for; 13% by weight of silver is slightly above 77.8% (FIG. 2).

0300A0 / 0741

- -31 '

The course of the synergistic curve can also be seen be that with the investigated catalyst with 7% SiI-over the sum of the content of cesium and potassium at least must be about 0.017% (based on the silver content) if the synergistic range is maintained with certainty should be, while the corresponding maximum content of cesium and potassium only in each case in the synergistic Range if the value of 0.016% is not exceeded.

The efficacy model and temperature model that have been developed relate specifically to a particular j Method of catalyst preparation, a special carrier! and a special binary alkali metal combination. deviation

j

030040/074 1

genes in either the process of manufacture or the carrier! cder the particular binary combination can use the coefficient; 5 cients of the model and accordingly also the shape j of the contour line maps that are derived from it. So ^; the curves "A" and "Be .." can be straight lines or [

Include curves and can intersect one or both axes
; (namely the cesium axis and that of the other alkali metal

j 10 in the binary combination). In Figures 1 and 2, the curves "A" and "Sel _Max " intersect both axes, with the cesium axis
j is cut at an angle greater than 90 °. With others <

Carriers, another manufacturing process, and others
However, in binary alkali metal combinations with cesium, the resulting curves "A" and "Sel _M " intersect the cesium axis

! O

j m an angle less than 90, or they can be parallel j run to one of the axes. The coefficients of the model

i and the contour maps obtained from it can be used for

^! 'each of the above-mentioned combinations can be easily determined.

j _{? 0} by the selected series of experiments - as previously described:

ί has been - is applied. '

The concentrations of silver in the finished catalyst
can vary from about 2-20% by weight, the preferred
; ₂₅ ferred range of about 6 to about 16 wt .-% of silver is ·. ^: Lower silver concentrations are less important than the economic
I preferred point of view. The optimal silver concentration
for any particular catalyst depends on both economic factors and performance characteristics
; ₃₀ such as effectiveness, degree of catalyst aging and reaction
; tion temperature.

; Catalyst manufacture

j For the production of the catalysts according to the invention, the I ₃₅ a combination of cesium and one or more other! Containing alkali metals (excluding francium) a variety of methods can be used. The preferred method includes:

030040/0741

1) Impregnating a porous catalyst support with a

Solution comprising a solvent or a solubilizing ⁵ agents, silver salt in an amount sufficient to deposit the desired weight fraction of silver on the carrier, as well as salts of a) cesium and b) at least ι of another alkali metal selected from the group: lithium j sodium, potassium and rubidium in amounts sufficient to

deposit corresponding amounts of a) and b) on the carrier,

so that the effectiveness of the finished catalyst j

increases to a value in the production of ethylene oxide, j

which is higher than the effectiveness values under i

normal conditions with appropriate catalysts j

is obtained, which are similar to the catalyst mentioned, but j

with the exception that these instead of a combination j of a) and b) each only have the corresponding amount of

a) or the corresponding amount of b). \

2) treating the impregnated carrier to at least j

ί a fraction of the silver salt to metallic silver { ι

convert j and the deposition of silver or of a); and b) effect on the carrier. Silver and alkali · Metal deposition is generally achieved by heating,; ? 5 of the wearer to elevated temperatures to the liquid 1 ί to evaporate in the carrier and the deposition of silver and

ί alkali metal on the outer and inner surface to j

i cause. Alternatively, a silver and alkali metal j

! coating on the carrier from an emulsion or

130 slurries are generated that contain these substances,

I whereupon the support is heated as previously described.

S The impregnation of the carrier is the generally

Preferred technique for silver deposition, because it uses SiI - ber ¹ more effectively than in the coating process;

35, the latter usually not having any significant silver [

! causes deposition on the inner surface of the carrier .;

y y

[Also coated catalysts for silver losses j more susceptible to mechanical wear and tear. ;

030040/0741

The order of impregnation or deposition on the
Surface of the support of silver and alkali metals can
can be freely chosen. Impregnation and deposition of silver and alkali metals can take place simultaneously or next to one another, ie the alkali metals can be deposited on the carrier before, during or after the addition of silver. i The alkali metals can be applied together or one after the other. It may, for example, cesium are deposited first, j followed by a simultaneous or successive _t deposition of silver and the or the other alkali metal (eh), or or the other alkali metal (s) may first off are stored ι, whereupon at the same time or one after the other

Deposition of cesium and silver occurs. \

;

The catalyst support is impregnated using one or more solutions containing silver and alkali metal compounds, according to known methods of simultaneous or successive deposition. For 1 simultaneous deposit after impregnation, the
impregnated carriers heat-treated or chemically treated,
to reduce the silver compound to metallic silver and to deposit the alkali metals on the catalyst surface. In the case of the successive deposition,

²⁵ the carrier is first impregnated with silver or alkali metal

(depending on the sequence used) and then - as ■ described above - heat-treated or chemically treated. ; This is followed by a second impregnation step with a
ι appropriate heat or chemical treatment to the

finished, silver and alkali metal containing catalyst: to manufacture.

The silver solution used to impregnate the carrier
. comprises a silver salt or a silver compound in one
Solvents or complexing / solubilizing agents such as known silver solutions. That used, special
Silver salt is not critical and can zBausgewählt \ be made: silver nitrate, silver oxide or Silbercarboxylaten <

030040/0741

• 34

such as silver acetate, oxalate, citrate, phthalate, lactate, j propionate, bulyrate and salts of higher fatty acids. . I.

S j To dissolve silver to the desired concentration in the!

Impregnation medium can use a variety of solvents j or complexing / solubilizing agents ■ ^! will. Suitable solvents for this purpose are I.

j!

- ₁₀ have been described, for example: lactic acid (US Pat. No. 2,477,435 and 3,501,417), ammonia (US Pat. No. 2,463,228) ^,!

• Alcohols such as ethylene glycol (US Pat. No. 2,825,701 and I

; 3,563,914) and amines and aqueous mixtures of amines J

: (U.S. Patents 2,459,896, 3,563,914, 3,702,259, and j

I ₁₅ A 097 414). j

ί I

i Suitable alkali metal salts include all those in!

j the special solvents used or solubilize -

^; are soluble in the agents. Accordingly, inorganic,

j ₂₀ and organic salts of alkali metals, we zR nitrates, {

j halides, hydroxides, sulfates and carboxylates used j

j will be. When deposited at the same time as the silver, [

, the alkali metal salt preferably one that is associated with the -

[ Silver salt in solution does not react to premature ,

j:

^: _ To avoid silver precipitation. Therefore, alkali metal! halides preferably not used in lactic acid solution; because they then react with the silver ions present in them.

; After the impregnation of the catalyst support with silver and alkali metal salts, the impregnated support particles are: from the remaining unabsorbed solution or slurry; mung separated. This is expediently carried out by draining _i \ of the excess impregnating medium or alternatively by using j of separation such as filtration

j or centrifugation. The impregnated carrier is then

^s generally heat treated (e.g. roasted) to reduce decomposition

! and the reduction of the silver metal salt to metallic

! Shem silver and the deposition of alkali metal ions

j cause. Such a roasting process can take place at one temperature

^L """'~ 03 00 A 0/0 7 ^ Ϊ

- • 32

from about 100 ^° C. to 900 ^° C., preferably from 200 to 700 ^° C., I can be carried out for a sufficient period of time to i

, essentially all of the silver salt to metallic SiI-; about to convert. The higher the temperature is, in general ', the shorter the required reduction period. : For example, the reduction can be achieved at a temperature of about 400 ° C.-900 ^° C. in about 1 to 5 minutes. Even though

Heating times for the heat treatment of the impregnated \ carrier according to the prior art within a wide
Range can vary (e.g. is in US patent specification
3 563 914 heating for a period of less than 300 seconds to dry, but not to reduce the:

Catalyst proposed by roasting; US patent specification
3,702,259 describes a heating period of 2 to 8 hours at a temperature of 100 ° C to 375 ° C to reduce the silver salt in the catalyst; in US patent
3,962,136 are suggested for 1/2 to 8 hours in the same temperature range), it is only important that the reduc-; tion time related to the temperature in this way
that a substantially complete reduction of the
Silver salt to metal is achieved. To this end
continuous or staged heating can be used.

The heat treatment is preferably carried out in air, it can
but also a nitrogen or carbon dioxide atmosphere
be used. In the devices for such
Heat treatment, a standing or flowing atmosphere of such gases can be used to carry out the reduction.

The particle size of the silver metal ab- j

or ^:

f is stored depends on the catalyst manufacturer used.

recruitment procedure. So the respective choice of ^:

j solvent and / or complex-forming agent, the SiI-

I over salt, the heat treatment conditions and the catalyst

030040/0741

I The carrier should preferably not contain any ions associated with the alkali metals applied to the carrier are interchangeable, neither in manufacture nor

satellite carriers influence the size of the resulting silver particles to varying degrees. In the case of carriers who are position of ethylene oxide are generally known, one normally obtains a distribution of the silver particles in one

Particle size range from 0.05 to 2.0 / u. However, the role is which is the particle size of the silver catalyst in terms of I.

I the effectiveness of the catalyst in the production of ÄthV-

jio lenoxid is playing, not very clear. Considering the fact)

I that it is known that the silver particles on the cat-

I migrate the surface of the lyser when the catalytic

j-response can be used, which is a noticeable change

j its size and shape should result in the size of the

₁₅ silver particles will not be a major factor affecting itself

; affects catalyst performance. I.

j selection of carriers

The catalyst support used according to the invention can be made from

²⁰ conventional, porous, refractory materials can be selected,

! which are essentially inert to ethylene, ethylene oxide

; and other reactants and products among the

j are reaction conditions. These substances become general

i called "macroporous" and consist of porous material

• ²⁵ fen with a surface area of less than 10 m / g.

; The surface value is determined using conventional B.E.T. methods

■ according to Brunauer S. et al, J.Am.Chem.Soc., Volume 60, pp. 309-16

> (1938) measured. You are still through a pore volume

I in the range of about 0.15-0.8 ccm / g, preferably from

j30 marked about 0.2-0.6 ccm / g. The pore volume can

j with conventional mercury thermometry or water drainage

j sorption technology can be measured. Mean pore diameter

i knives for the carriers described above are approximately

I 0.01-100 / u, preferably from about 0.5-50 / u.

⁺ preferably less than 1 m / g

when using the catalyst, so that the amount of alkali metal is not changed, which creates the desired synergism supplies. If the carrier contains such ions, j

should these be removed using standard chemical processes such as leaching. If the carrier contains as such a quantity of alkali metal that can reach the silver is disturbed whereby the synergistic ratio, then the j carrier should be treated to remove the excess alkali metal \. Alternatively, the amount of alkali metal fed to the catalyst should be less than the synergistic amount, with the _{alkali metal derived from the carrier:} the desired synergistic amount ^;

₁₅ included.

The chemical composition of the carrier is not critical. Carriers can e.g. be made of oC aluminum oxide, silicon carbide, Silicon dioxide, zirconium oxide, magnesium oxide and

20 schxedenei Tonai exist. Materials based on

α-alumina are generally preferred. These on FLC aluminum; Substances based on minium oxide can be of great purity: e.g. 98 +% by weight «^ aluminum oxide, with the remaining Components silicon oxide, alkali metal oxides (e.g.

Sodium oxide) and traces of other metals and non-metallic ones Are impurities. But they can also be of low purity, i.e. about 80% by weight of aluminum oxide, where the difference is a mixture of silicon oxide, various alkali oxides, alkaline earth oxides, iron oxide and other> -

_'30 ren metal and non-metal oxides. The carriers of lesser purity are formulated in such a way that they are used in the catalysis; sator production and are inert under the reaction conditions. A wide variety of such carriers are available on the market. The carriers can be in the form of pellets, extruded particles, spheres, rings, and the like. The ^: carrier size can vary from approximately 1.6mm - 12.7mm. The carrier size is chosen in accordance with the type of reactor used. In fixed bed reactor applications j are generally support sizes of about 3.2 mm - 9> 6 mm

for the typical tubular reactor used in technical operations is most suitable. j

Ethylene Oxide Production I

The silver catalysts of the invention are particularly suitable for use in the production of ethylene oxide by gas

ι phase oxidation of ethylene and molecular oxygen!

suitable. The reaction conditions for carrying out the Oxidati *

onsreaktion are known and have been described in detail, j

This relates to reaction conditions such as temperature, pressure, residence time, concentration of the reactants,:

Diluents (e.g. nitrogen, methane and COp), inhibi- f gates (e.g. ethylene dichloride) and the like. Furthermore, j recirculating unreacted feed, using a 1 pass system, or using j successive reaction sequences to increase the ethylene conversion by using reactors in series; easily applied by those skilled in the art if expedient. The ■

! the respective process method is usually dependent on economic

Considerations determined. :

In general, the process is carried out so that a
? s the catalyst containing reactor continuously with a ^!

Ethylene- and oxygen-containing stream at one temperature
of about 200 - 300 C and a pressure between 1 at and \

about 30 at, what depends on the mass velocity
^: and the desired productivity depends, is charged.
'30 The residence time in large reactors is generally '! about 1 to 5 seconds. Oxygen can be used in the reaction

• Form of an oxygen-containing stream, such as air or ^:

technical oxygen. The emerging! Ethylene oxide is separated and made from the reaction products Us separated using conventional methods.

030040/0741

Catalyst comparative tests

The catalysts \ listed in the following table are all evaluated for comparison purposes under standard encryption \ search conditions using "magnedri ve" j-Rückraischungsautoklaven as in Figure 2 of the publication;

by J.M. Berty "Reactor for Vapor Phase-Catalytic

Studies "in Chem. Ingineering Progress, Vol. 70, No. 5, p. 78; - 84 (197A). The reactor was operated with 1.0 mol% ethylene oxide in the effluent gas under the following standard Loading conditions operated: \

component Mole% 15th oxygen 6.0 Ethylene 8.0 Ethane 0.50 Carbon dioxide 6.5 nitrogen Rest gas 20th Tpm ethylene chloride = 7.5

The pressure was kept constant at 19.2 atmospheres and the

3 (1)
stepping total flow at 0.64 m / h. The concentration of the effluent ethylene oxide was kept at 1.0 % by regulating the temperature. The temperature (C) and the catalyst efficiency are obtained as results indicating the catalyst efficiency.

A typical catalyst test procedure involves the following steps:

1. 80 ecm of catalyst are placed in a backmixing autoclave given. The volume of the catalyst is measured in a measuring cylinder with an inner diameter of 2.54 cm, which was pushed open several times to create a compact catalyst filling to reach. The weight of the catalyst is recorded.

at standard temperature and standard pressure, namely 0 ⁰ C and 1 at 030040/0741

2. The backmixing autoclave is heated to approximately the reaction temperature with a nitrogen flow of 0.566 m / h, with the fan running at 1500 rpm. The nitrogen flow is then interrupted and the above-described loading; feed stream passed into the reactor. The entire exiting The gas flow is adjusted to 0.64 m / h. The ΐ

/ few temperature will be regulated in the next few hours, * that the ethylene oxide concentration in the exiting gas

is about 1.0%. ^;

3. The concentration of the exiting oxide is recorded over the next 4 to 6 days to ensure safe; ensure that the catalytic converter has reached its constant maximum output. The temperature is displayed periodically; equal to get 1% oxide in the exhaust gas. The selectivity of the ■ catalyst to ethylene oxide and the temperature ture values are obtained in this way. j

The standard deviation of a single test result! j ²⁰ according to the method described above is 0.7% units of activity. ■

The following Tables II to VI summarize the test results together, obtained with silver catalysts in absence: ■ ^2b integral of additives and catalysts, the cesium in grain \ \ bination with one or more alkali metals selected from the

Group: contained lithium, sodium, potassium and rubidium. ;

The experiments are carried out using a plurality of;

Catalyst carriers and various manufacturing processes ,

• ³⁰ carried out. Catalysts made by the same process ^

: were made on a similar support are in the

Table denoted by a common number. ]

i 35

030040/0741 ^j

ORIGINAL INSPECTED

attempt

Table II

Wt% Ag

Wt% Cs

Weight - ⁰ / K

■ X ·· *

Active sarak. in %

1 A

1 B.

1 C

1 D

1 E.

1 F.

1 G

1 H.

1 I.

1 y

1 K

1 L

1 M.

1 N

1 O

1 p

1 Q

1 row

1 p

2 A

2 B

2 C

2 D

2 E.

2 F

2 G

2 H

11.14 0. 00479 11.14 0. 00477 10.89 0. 00461 10.41 0. 0000 10.80 0. 0000 10.93 0. 0000 10.90 0. 0000 04/11 0. 00941 06/11 0. 00941 10.92 0. 0186 11.16 0. 0191 8.0- 0. 004 7.8-i - 8.28 0. 0041 8.07 • - 14.97 ■ - 15.19 0. 0040i 14.80 - 15.10 0. 004 17.4 0. .000 16.6 0. .0044 16.5 0, .0085 17.3 0 .000 17.0 0 .0044 15.7 0 .0044 16.5 0 .0092 16.5 0 .0092

0.0000 71.7 256 0.00158 73.9. 256 0.00450 75.4 256 0.0000 68.4 265 0.00613 69.9 261 0.0123 73.3 26-i 0.0210 66.6 299 0.0000 75.6 256 0.00313 76.9 256 0.0000 73.1 263 0.00633 72.0 293 0.008 76.0 269.3 0.0078 75.0 263.6 - 73.8 253.3 - 67.3 2cö.O - 66.7 252.9 - 72.6 252.0 0.0079 75.5 255.5 0.0081 77.9 256.6 0.093 73.5 278 0.088 74.7 279 0.089 74.2 278 0,000 68-67 * 284-299 0.0016 70.8 276 0.069 74.1 280 0.0028 72.2 275 0.088 73.2 267

! *
; 35

Due to the rapid reactivation of this catalyst, the initial and final performance are given.

Efficacy is used here as defined above.

030040/0741

Experiments 1B and 1C show the synergism that can be achieved with

Obtains silver catalysts, which according to the invention contain mixtures 5 of cesion and potassium, in relation to the "only-

Cesium "catalyst below 1A, which is essentially the same!

Concentration of silver and cesium, but no potassium. The term "cesium only" catalyst, like it is here ^! 'is used refers to a catalyst wherein

j;

j ίο cesium is the only alkali metal that ab- j j was stored. The term "potassium only", "lithium only"; · ■ and "Sodium only" are corresponding names for the ■ 'related catalysts. The effectiveness you get with! Combinations of alkali metals obtained in Experiment 1B was' us about 2% higher than those with the corresponding "Nur- t Cesium "catalyst was achieved in Experiment 1A. A ■ further addition of potassium in an amount of 0.00158% (example 1B) up to an amount of 0.0045% potassium (example ld), whereby silver and cesium were kept essentially constant den, brought an even greater improvement in efficacy

compared to 1A, namely of about 3.7%. The catalyst j

tor from experiment 1D contained no cesium or potassium and

gave a relatively low effectiveness of 68.4%. The Ver- ;

Seek 1E, F and G show that "potassium only" catalysts j

? s essentially contained the same amount of silver as the \ catalysts 1B and 1C, a selectivity of

gave no more than 73.3%, which is significantly lower; than those with catalysts 1B and 1C, the mixtures
\ of cesium and potassium contained results.

It should also be noted that in addition to creating
the catalysts according to the invention are more effective
(1B and 1C) can be used at lower temperatures
could be considered the "potassium only" catalysts (1E, 1F and 1G),
which is a sign of the higher catalyst activity,
Although the "cesium only" catalyst (1A) at the same
At a low temperature, such as the catalysts 1B and 1C, could be used, this resulted in a significantly lower effectiveness. j

\ 030040/0741 J.

The catalyst of Run 1H was a "cesium only" Cat-I

/ in j

lysator, the amount of cesium almost twice as large as;

5 1A, B and C included. The addition of 0.0031% potassium to |

a catalyst of such a composition gave an i

Effectiveness improvement by more than 1%, like this one!

'Example 1 shows. ■

«Ίο Tests U and 1K show a non-synergistic combination _:

i nation of cesium and potassium. The addition of potassium too

j the "cesium only" catalyst U, which contains about 11% silver and ί

a relatively high cesium concentration of 0.00186% ent-; held, gave a catalyst (1K) of lower potency

^ ₁₅ and higher process temperatures. That means that!

: the combination of potassium and cesium in experiment 1K no j

j produced a synergistic result. Such a cesium

> i

i Potassium mixture is not according to the invention. ;

■ j

J ₂₀ Experiments 1L to 10 show the synergism according to the invention;

j for catalysts that contain about 8% silver. The effective \

• Samidity of the catalyst 1L, which is a synergistic combination; j nation of cesium and potassium contained was 1 % higher than that
of the "potassium only" catalyst 1 M and more than 2% higher than
: _{? 5} the effectiveness of the "cesium only" catalyst 1 N. The silver. ! catalyst 10, which contained neither cesium nor potassium, gave an effectiveness nearly 9% lower than catalyst 1L.

j _"n The experiments 1P to 1S show the synergy of the invention; i gism for catalysts that contain about 15% silver.

! The effectiveness of Catalyst 1S, which is a synergistic. } Mixture of cesium and potassium contained was more than 5%

j higher than that of the "only cesium" catalyst 1Q of the ·

L, corresponding amount of cesium in such a mixture j held, and about 2.5% higher than the "potassium only" catalyst

1R, which has the corresponding amount of potassium in such a \

Mixture contained. The catalyst 1P, which does not contain any additives'

030-040 7-074-1-

-H

showed an effectiveness about 11% below that of des
Catalyst 1S.

Experiments 2B and 2C show the effectiveness values that can be achieved with potassium-cesium mixtures for a catalyst
I which contained about 17% silver compared to the "I potassium only" catalyst of Run 2A. The addition of 0.0044% I ¹⁰ cesium in Experiment 2B resulted in improved effectiveness
i of 74.7% compared to an effectiveness of 73.5%,

obtained in Experiment 2A. The silver catalyst 2D,
j in which no alkali metal has been applied to the support

^{1 is included} in the table for comparison.
; ■ 15

j A comparison of experiments 2E and 2F shows that in one
j Increase in potassium concentration from 0.0016% to 0.069%,
I while the cesium content was kept constant, an improvement in the effectiveness of more than 3% was achieved.
! ²⁰ Similarly, a comparison of Experiment 2G and 2H shows that

j when increasing the Kalxumzentratxon - during the silver I and cesium content remained constant - an improvement in

; Effectiveness of 1% was achieved. '-

ι ■? 5 Three catalysts with 7% silver were produced,!

the optimum cesium concentration according to the effectiveness "> keitsmodell that was created when a batch _corresponds: held. The catalysts (Runs 3A, B and C) included
all about 7.0 wt% silver and 0.00906 wt% cesium, where
130 no potassium was present. In order to show how the effectiveness model works, three additional catalysts were ■! posed (experiment 3D, E and F), each of which about 7%; ; Containing silver, 0.00906% cesium and 0.004 % potassium. Of the ;

ι f

j Difference in the performance of the cesium / potassium catalysts

t;

! 35 compared to the "cesium only" catalysts could by means of the>

Effectiveness model to about 0.6% effectiveness units! be determined. As indicated in Table III below ⁵ , j the actual difference in performance was 0.7%;

i 030040/074 1. ^j

what is considered to be in accordance with the effectiveness model

can look at. Experiment 3G shows the effectiveness of a ⁵ "potassium only" catalyst containing silver and potassium in the same concentrations as the catalysts of experiments 3D, E and 'F, thus demonstrating the synergism:

I obtained with cesium-potassium combinations.

j Table III

"Cesium only" catalysts: 7.0% Ag, 0.00906% Cs

! attempt

! 15th

effectiveness
in % temperature
in ° C 75.4 263.9 75.7 261.4 75.4 266.1

I · 3A

I 3B

j 3C

j 20

¹ 'Average: 75.5 + 0.17 *

Cesium + potassium catalysts: 7.0% Ag ,

; 2b 0.00906% Cs, 0.004% K

; 3D 76.0 271.4

I 3E 76.1 271.5

j 3F 76.4 270.9

ι 30

\ Average: ⁷ 6.2 + 0.21 *

l "Potassium only" catalyst : '{ _f 0% Ag, 0.0040% K

S 3G 72.8 265.3

! 35

i *

The values indicate the standard deviations.

30.040 / 0741

The following Table IV shows the synergism achieved with a combination of cesium and lithium (experiment> compared to the corresponding "cesium only" catalyst of experiment AA and the corresponding "lithium only" catalyst of experiment AB. The AC catalyst was about 10% more effective than the "lithium only" catalyst: AB and about 3.5% more effective than the "cesium only" catalyst ^j! Io AA. J

'I.

j Experiment AD shows that with an increase in the lithium j

^! : Concentration of the catalyst AC by about ten times, j the efficiency achieved was reduced by more than 3%, j However, a comparison of the catalysts AD and AE shows that j that the efficiency obtained with catalyst AD! could be increased again by increasing the cesium concentration from 0.0053% to 0.0300%. It should be noted that the "cesium only" catalyst of test AG (corresponds to the cesium concentration of AE) was inactive, ie) that no ethylene oxide was produced at this cesium concentration. However, the combination of this concentration of cesium with 0.0300% lithium resulted in a very active catalyst (AE). Similarly, the "lithium only ¹ * -

2b catalyst AF (corresponds to the lithium concentration of AE) j a relatively low effectiveness of 65.A %. The syner! The result obtained with Catalyst AE is underlined by the sharp contrast between its effectiveness and the poor results obtained with Catalysts AF and AG. j

0 J3JO 0 AO / JO YES I

- 44 Table IV

Catalysts with synergistic combinations of silver, cesium and lithium

attempt Wt% Ag Wt% Cs Wt% Li 4Α 12.8 0.0052 0,000 4Β 13.1 0,000 0.0030 4C 12.8 0.0052 0.0030 4D 13.1 0.0053 0.0302 4E 13.0 0.0300 0.0300 4F 13th 0,000 0.0300 4G 13.0 0.0300 0,000

Effectiveness temperature
in% in C.

72.6 257 65.9 267 76.0 257 72.8 258 78.6 258
m 65.4 268 Inactive "*

No measurable amount of ethylene oxide was obtained.

I 25 , "3O

j 35 ι

The following Table V shows the synergism that can be achieved with the catalysts of Experiment 5C compared to the corresponding "cesium only" catalysts of experiment 5A and the corresponding "sodium only" catalysts Trial 5B received. Catalyst 5C showed 6% greater efficiency than "cesium only" catalyst 5A and one µm j 7.2% greater effectiveness than the "sodium only" catalysis • io sator 5B. Experiment 5D shows that an increase in the sodium concentration by ten times in relation to the Konzenj tration in the catalyst 5C gave the result that the catalyst efficiency was reduced.

20 i

ι I.

- 46 -

Table V

attempt Catalysts with synergistic combinations silver, Cesium and sodium temperature
in ⁰ C 5A Wt% Ag wt% Cs Wt% Na effectiveness
in % 257 O
co
O
O 5B 12.8 0.005 0,000 72.6 259 5C 13.0 0,000 0.010 71.4 251 O 5D 13.0 0.005 0.010 78.6 263 * x 12.4 0.005 0.100 77.6.

The following Table VI shows the synergism that can be achieved with
a catalyst is obtained which contains silver and cesium in combination with potassium, sodium and lithium, as indicated in Experiment 6Ά . The presence of chloride ions in the catalysts 6A, B and C indicates that at least part of the alkali metal salt is present that in the production of catalysts' ^! was used, was in the form of chlorides. The effective! [io sameness obtained with the synergistic combination of; Test 6A received was about 1.2% greater than the effectiveness
j of the corresponding "cesium only" catalyst of FIGS. 6C and
j about 9% larger than the corresponding combination of potassium, j sodium and lithium for catalyst 6B.

3Q..0 4Q / Q.741

I.
f
i co
Oil Wt% CO "U
ο yi tab e 1 48 -
1 e .-% K Weight .-% N / A VI potassium , Sodium Ul j
ί Catalysts with 13.1 synergistic combinations 001 0. 002 Silver, cesium, Wt .-% Li wt .-% Cl Effective
in % •
and lithium S. attempt 13.0 Ag wt .-% Cs wt 001 0. 002 0.006 0. 78.4 * . temperature
in ° C ! CO 6A 13.1 0.0132 0. 000 0. 000 0.006 0. 69.4 262 ^ CD 6B 0,000 0. 0,000 0. 77.2 267 jo 6C 0.0132 0. , 0137 265 0137 0035

The effectiveness is the average of two trials.

The catalysts of the invention can be prepared on a variety of supports and by various processes. The described synergism obtained with combinations of cesium with other alkali metals is
e.g. not on a particular type or chemical composition of the catalyst carrier, a certain sequence of \

! 1

j silver and alkali metal deposit or on a ^;

! ίο special group of solvents or solubilizing agents!

used in its manufacture. I.

030040/0741

ι - -re-

"-SS-

example 1

An 11.14 wt% Ag, 0.00477 wt% Ji Cs, and 0.00158 wt% Ji Catalyst containing K was prepared in the following manner on oC clay carrier "A" with the following chemical Composition and physical properties

posed:

chemical_composition_of_ carrier __ ^ A ^

; 98.5 oC alumina

j io silica 0.74

; Calcium oxide 0.22

Sodium oxide 0.16

Ferric oxide 0.14

Potassium oxide 0.04

is magnesium oxide 0.03

Surface value (1) a / 0.3 m / g

Pore volume (2) rv> 0.50 ccm / g

(or water absorption)

Fill density (3) 0.70 g / ml

• Average pore diameter (4) 21 microns

Pore size; Micron % d.Total pore volume

0.1-1.0 1.5

? s 1.0-10.0 38.5

10.0-30.0 20.0

30-100 32.0

> 100 8.0

(1) Measurement method according to "Aösorption, Surfce Area and Porosity" S.J. Gregg and K.S.W. Sing, Academic Press (1967),

Pages 316 to 321

(2) Measurement method according to ASTM C20-46

(3) calculated value based on a common weight measurement of the carrier in a container with known

'35 volume

(4) Measurement method according to "Application of Mercury Penetration to! Materials Analysis", C. Orr Jr., Powder Technology, Vol. 3 _t

I pages 117 to 123 (1970)

■ κ ·
j Synonym for aluminum oxide

0300A0 / 07A1

j * Carrier "A" was impregnated under vacuum with a solution of silver salts and alkali metals as follows. The Impräg * nating solution was prepared with such a concentration,

b that the final catalyst has the desired amounts Contained silver, cesium and potassium. The necessary concentration of silver, cesium and potassium in the solution for the given carrier was calculated from the bulk density (g / ccm) and the pore volume of the carrier, which are either known

ι · * are or can be easily determined. Under the assumption, that all silver in the impregnation solution contained in the carrier pores is deposited on the carrier about 21% by weight of silver in the solution is necessary to produce a catalyst containing about 11% by weight of silver.

ι. ¹ · The necessary alkali metal concentrate in the solution is obtained by dividing the silver concentration of the solution by the desired ratio of silver to cesium or potassium in the final catalyst. To achieve 11.0% by weight of Ag and 0.0047% by weight of Cs, the ratio? N is about 2330, and the necessary cesium concentration in the solution is 0.009% by weight. Similarly, the potassium concentration of the solution was calculated to be 0.003% by weight. The solution containing the desired concentrations of silver and alkali metals was prepared as follows:

80.16 g of highly pure ethylenediamine were 176 g least. Water mixed, whereupon to this solution slowly at room temperature (23 ° C) with constant stirring 60.06 g anhydrous oxalic acid (for reagent use) was added. The temperature of the solution rose during the addition of oxalic acid due to the exothermic reaction to about 40 ° C. Then 147.25 grams of silver oxide powder (Handy and Harmon, New York) was made Added diamine / oxalic acid / water solution. Finally, 29.30 g of monoethanolamine and 13.26 g of aqueous Cs hydroxide solution were added (0.00444 g Cs / ml solution or 0.0589 g Cs), 34.28 g aqueous K-carbonate solution (0.0005669 K / ml solution or 0.0194 g K) and 120.6 g dist. Water added to the

030040/0741 QPIHJINAL INSPECTED

st-

Complete solution; this was filtered and 0.9 g of undissolved silver was recovered. The spec. The weight of the solution obtained was about 1.328 g / ml.

125 g of carrier "A" were impregnated in a cylindrical glass vessel 30 cm long and 5 cm internal diameter, which was provided with a side arm and suitable closures for carrier impregnation under vacuum. A 500 ml separatory funnel for receiving the impregnation solution was inserted into the top of the impregnation vessel through a rubber stopper. The impregnation vessel containing the carrier was evacuated to about 50 mm Hg pressure for about 20 minutes, after which the impregnation solution was slowly added to the carrier by opening the seal between the separating funnel and the impregnation vessel until the carrier was completely floating in the solution; while the pressure in the vessel was kept at about 50 mm Hg. After the addition of the solution, the vessel was opened to come to atmospheric pressure with the carrier immersed in the impregnation solution for about 1 hour at ambient temperature and pressure, and then the excess solution was allowed to drain for about 30 minutes. The impregnated carrier became as follows heat-treated to reduce the silver salt and deposit cesium and potassium ions on the catalyst surface; it was spread in a single layer on an approximately 6.7 cm wide, endless belt made of stainless steel (spiral fabric) and passed for 2.5 minutes through a square 5 × 5 cm heating zone which was kept at 500 ^° C. by heating air upwardly led through the belt and about the catalyst particles in an amount of about 266 SCFH \. The hot air was generated by passing it through a stainless steel pipe 1.5 m long and 5 cm internal diameter, which was passed from the outside through an electric oven (LINDBERG tubular oven: 6.35 cm internal diameter, 90 cm long heating zone), which had 5400 watts of power. The hot air

V, 53 cm ³ / h

0 3 0040/074

, * in the tube was ejected through a square 5 x 5 cm opening immediately below the moving, the tape leading to the catalyst carrier was located. To

^: & Roasting in the heating zone, the finished catalyst was weighed. According to the calculation based on the increase in weight of the carrier and the known ratios of silver to cesium and potassium in the impregnation solution, it contained 11.14% by weight silver, 0.00477% by weight cesium and 0.00158% by weight. -% ίο potassium. According to the chemical analysis described below, this catalyst contained 10.88 % Ag which is close to the calculated value.

Analysis for silver is carried out by the following procedure. A sample of catalyst of about 50 g was pulverized in a mill, and 10 g of the same was weighed to an accuracy of 0.1 mg. The silver (and cesium etc.) in the catalyst sample was hot in a 80 ⁰ C, 50 vol dissolved -96igt nitric acid solution. The insoluble alumina particles were filtered and treated with distilled water to remove all adhering nitrate salts of Ag, Cs, etc. Water washed. This solution was made with dist. Bring water to 250 ecm in a volumetric flask. A 25 ml aliquot of this solution was titrated according to standard methods using a 0.1 ". Solution of ammonium thiocyanate and ferric nitrate as an indicator. The amount of Ag so contained in 250 ml of solution was then used to determine the percentage by weight of silver in the Calculate catalyst sample.

: «) The calculated values of the silver and alkali metal concentrations for all catalysts present were determined as above.

Example 2

A 16.6 wt% Ag, 0.0044 wt% Cs, and 0.088 wt% K

»> Containing catalyst was prepared as follows on a carrier" B "with the following properties:

Qι 3 0 0 A 0/0 7 4 1 ORIGINAL INSPECTED

'£ ^ SSi5 £ li®-2HSäi222iiS2i5üSS_Y22.2EäS§ ^r ' - " ^B " _Weight .-%

; o (-Alumina 86.0

, Silica 11.8

I 5 calcium oxide 0.24

• Sodium Oxide 0.69

[ Ferric oxide 0.30

Potassium oxide 0.54

Titanium dioxide 0.34

¹⁰ 2iiY5iiS§iiS £ i} S-5iS§S5 £ ^ ä £ i®S-Y2S_Si! ÄSS ^r " ^B "

Surface area (1) 0.10 m ² / g

Pore volume (2)

(or water absorption) 0.40 cc / g

Fill density (3) 0.72 g / ml

: ₁₅ average pore diameter (4) 22 microns (1) to (4) = see example 1

Pore size; Micron % of the total pore volume 0.1-1.0 0.0 1.0-10.0 12th 10.0-30 55 30 -. 100 33 > 1OO 0.0

The manufacturing process consisted of the following steps: (i) 333.5 g of lactic acid (88% / water) were brought to about 75 ° C heated, and 1.44 g of KpCO-, and were added with stirring 4.86 g aqueous CsOH solution (with 0.008 g / ml or 0.039 g Cs) was added.

(ii) 163.75 grams of Ag ₂ O (Metz Meallurgical Corp. USA) was added batchwise to the heated lactic acid with stirring so that the _{heat generated from the exothermic reaction of Ag 2} O with the lactic acid did not rise above about 85 ° C. Most of the Ag ₂ O and / or silver was left suspended in the solution; this suspension was dark brownish-gray in color.

030040/074

- (iii) 3.3 ml of hydrogen peroxide were added batchwise to; Add the above Ag ₂ O / lactic acid solution with vigorous stirring ^;

j added to completely dissolve the suspended material.

! A clear yellow solution whose temperature was about 8O ⁰ C 5 was obtained. (Small amounts of lactic acid or water

! were added to make up for evaporation losses.) This solution contained approximately 30.4% silver, 0.12 % K and 0.0078 % Cs.

id (iv) 189 g carrier "B" were evacuated and impregnated with the compound prepared in (iii) solution at a temperature of about 80 ⁰ C. The impregnation process of the support was 'described in Example 1, whereby in addition the cylindrical containing the carrier impregnation vessel' was surrounded with a heating mantle, the ^{Trägertempera-:} door held during impregnation at about 80 ⁰ C to ensure that the silver lactate in Solution remained. : (v) Then the impregnated carrier from (iv) was 4 minutes at 40O ⁰ C using those described in Example 1.

? [) Device and the process mentioned there. ; Example 3

A 13.4 wt. # Ag, 0.0091 wt. Ji Cs, and 0.0027 wt. 96K Catalyst containing was as follows on the in

:> · Carrier "A" described in Example 1 prepared. Production_of_ the_regulation solution

78.6 g of high purity triethylenetetramine were distilled with 80 g. Water mixed, then were slowly taking Stir to the amine solution 51.57 g of oxalic acid dihydrate

^3t) (for reagent purposes) was added. During this addition, the temperature of the solution rose to 60 ° C. due to the exothermic reaction. Subsequently, 5.83 g aqueous cesium hydroxide solution (0.009728 g Cs / g solution) and 4.46 g aqueous potassium carbonate solution (0.00369 g K / g solution) as well as 89.26 g silver oxide (Metz Metallurgical Corp.) were added . Finally, 15.28 g of monoethanolamine were added together with further dist. Water was added to the solution to a total volume of 250 ml. The solution was filtered,

030040/074

30105 ^: 3

and about 5 g of undissolved silver was recovered.

150 g of carrier "A" were evacuated at room temperature and impregnated according to Example 1 with the above impregnation solution. The carrier was then heat treated for 2.5 minutes at 50O ⁰ C according to the device and method of Example 1.

'••' The composition of the finished catalyst, calculated from the increase in weight of the support, was as given above. Example 4

A catalyst containing 13.04 wt% Ag, 0.0089 wt% Cs, and 0.0026 wt % K was prepared as follows on that in Example

i ^r > 1 described carrier "A" produced.

114.25 g of highly pure Aminoäthyläthanolamin were with 80 g dist. Water mixed, then 50.42 g of oxalic acid dihydrate were slowly added with constant stirring (for reagent purposes)

^ "added to the solution, the temperature rose due to the exothermic reaction to about 60 ⁰ C. Then, 5 _t 84 g of aqueous cesium hydroxide solution (0.009723 g Cs / g solution) and 4.52 g of aqueous Kaiiumcarbonatlösung (0.00369 g K / g solution) to the solution as well as 89 g silver oxide (Metz Metallurgical Corp.)

"'Added, whereupon further distilled water to a total volume of 250 ml was added.

150 g of carrier "A" were evacuated and impregnated according to Example 1 with the above solution. The heat treatment of the impregnated

■ ""'nated carrier took place for 2.5 minutes at 500 ⁰ C according to the device and method of Example 1.
Example 5

According to Example 1, a catalyst having nominally the same composition as the catalyst of Example 1, namely

³⁵ 11.1 wt .-% Ag, 0.0048 wt .-% Cs and 0.0016 wt .-% K, prepared, however, the preparation of the impregnation solution using aqueous solutions of cesium chloride

030040/074

- and potassium chloride instead of cesium hydroxide or potassium carbonate took place. After adding these chloride salts to the silver-containing impregnation solution, the solution remained clear, i.e. s no precipitation of silver chloride was observed.

Example 6

A catalyst having nominally the same composition as the catalyst of Example 1 was prepared (namely 11.0% by weight Ag, 0.0047% by weight Cs and 0.003% by weight

ίο Li), using lithium instead of potassium; the The lithium concentration of the solution was calculated to be 0.00573% by weight. In the manufacturing process according to Example 1 instead of the potassium carbonate solution, 34 g of an aqueous' Lithium carbonate solution (0.001094 g lithium / ml or

i '> 0.0372 g lithium) was added to the impregnation solution. Example 7

According to Example 1, a catalyst with nominally the same composition, i.e. 11.0 wt. - 96 Ag, 0.0047 wt. - 6 Cs and 0.01 wt. 96 Na, using sodium instead

pd made of potassium, the sodium concentration being the The solution calculated was 0.0191 96% by weight. In the process of In Example 1, instead of potassium carbonate, 34 g of an aqueous sodium carbonate solution (0.00365 g sodium / ml or 0.12415 g sodium) was added to the impregnation solution.

. '·> Example 8

A 12.59 wt. 96 Ag, 0.0088 wt. 96 Cs and 0.0025 wt. 96 K Catalyst containing was prepared on carrier "A" described in Example 1 by sequential impregnation procedure made in which potassium and cesium

™ deposited on the carrier prior to the deposition of silver as follows were: 146.1 g of carrier "A" were mixed with 250 ml of an aqueous, 0.0 5696 g cesium hydroxide and 0.1674 g potassium carbonate containing solution impregnated according to the impregnation method of Example 1. Then the impregnated

«Nated carrier heat-treated for 2.5 minutes according to Example 1 at 40O ⁰ C in order to deposit cesium and potassium ions on the carrier surface. After this heat treatment, the carrier was coated with the silver-containing impregnation solution as follows

030040/0741

treated:

48.9 g of highly pure ethylenediamine were distilled with 80 ml. Water mixed, whereupon 50.6 g of oxalic acid dihydrate (for reagent purposes) were added to the solution within one hour with constant stirring. During the oxalic acid addition, the temperature of the solution rose due to the exothermic reaction to about 4O ⁰ C. Next, oxalic acid / water solution 89.34 g of silver oxide (Metz Metallurgical Corp.) was added to the diamine /, whereupon the solution 17.84 g monoethanolamine together with further dist. Water were added to a total volume of 250 ml.

The above carrier "A" was impregnated with the impregnation solution prepared as above and then heat-treated ^{according to Example 1 at 40O 0 C for 2.5 minutes.} Example 9
A 13.09 wt .-% Ag, 0.0089 wt .- # Cs and 0.0026 wt -.% K-containing catalyst was prepared in the manner described in Example 1 ^W A carrier "by sequentially impregnation method in which silver from the Deposition of potassium and cesium was deposited on the carrier as follows:

5 Preparation of the silver-containing impregnation solution

48.43 g of highly pure ethylenediamine were added with 100 g least. Water mixed, whereupon for solution at room temperature with constant stirring slowly 50.75 g of oxalic acid dihydrate (for reagent purposes) have been added; due to the

• 3o exothermic reaction increased the temperature of the solution to about 60 ⁰ C. Then Qxalsäure / water solution were added 88.97 g of silver oxide (Metz Metallurgical Corp.) to the diamine / added. Finally, 17 »7 g of monoethanolamine and 44.0 g of dist. Water to complete the solution

35 adds, whose spec. Weight was 1.3957.

030040 / 07A1

150 g of carrier "A" were impregnated with the above solution and then heat-treated ^{at 500 ° C. for 2.5 minutes as in Example 1.} After this heat treatment, the carrier is impregnated with the impregnation solution as follows: Production of the impregnation containing cesium and potassium

5.791 g aqueous cesium hydroxide solution (0.009723 g Cs / g π. Solution) and 4.415 g aqueous potassium carbonate solution (Ο, ΌΟ369 g K / g solution) were placed in a 250 ml measuring cylinder, whereupon this up to the 250 ml mark was filled with n-butanol. The cylinder was heated to 40 ⁰ C, and sealed to obtain a clear solution vigorously _ir, shaken.

Catalyst manufacture

The above-described silver-containing carrier "A" was impregnated under vacuum with the cesium- and potassium-containing impregnation solution for 15 minutes, then the excess solution was drained off as in Example 1. The carrier was heat treated for 2.5 minutes at 500 ^° C. as in Example 1.

030040/074

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Claims (9)

Claims 1. Supported silver catalyst for the production of ethylene oxide, characterized in that it is a combination of a) cesium and b) at least one other alkali metal from the group: lithium, sodium, potassium and rubidium contains, wherein the combination of a) and b) comprises amounts (based on the amounts of silver) which are sufficient to increase the efficiency of ethylene oxide production to a value that is greater than the efficiency values, which are obtained under the usual conditions with appropriate catalysts which are similar to the process mentioned, but with the exception that the one - instead of a combination of a) and b) - only the corresponding amount an a) and the other only contains the corresponding amount of b). 2. Catalyst according to claim 1, characterized in that silver in an amount of about 2 to about 20 wt .-%, preferably from about 6 to about 15 weight percent is present. 3. Catalyst according to claim 1-2, characterized in that said alkali metal is sodium, lithium, potassium or rubidium. -J 4. Catalyst according to claim 1-2, characterized in that the weight ratio of cesium to potassium of about Is 100: 1 to about 1: 100. 5. Catalyst according to claim 1-4, characterized in that the catalyst support comprises OL aluminum oxide. 6. Catalyst according to claims 1-5, characterized in that the surface area of the catalyst support is smaller than about 1 m / g. 7. Catalyst according to claims 1-6, characterized in that the pore volume of the catalyst support is from about 0.2-0.6 cm ² / g. 030040/0741 8. A process for the preparation of ethylene oxide, wherein ethylene
and oxygen in the gas phase at a temperature
from about 200 ⁰ C to 300 ⁰ C in the presence of a silver supported catalyst are converted to ethylene oxide
to form, characterized in that a supported silver catalyst according to claims 1-7 is used. ίο 9. Process for the production of a supported silver catalyst! for the production of ethylene oxide by gas phase oxidation S of ethylene with an oxygen-containing gas, thereby j characterized in that the method comprises: I. I) impregnation of a porous catalyst support with a solution containing a solvent or a soluble \ making agent, silver salt in an amount equal to- { I is sufficient, the desired percentage by weight of silver | ; "to be deposited on the carrier as well as salts of a) cesium S; and b) at least one other alkali metal from the group: lithium, sodium, potassium and rubidium in sufficient quantities, corresponding quantities of a) and b) on: the comprises depositing carrier, so that the efficiency of the finished catalyst J increases in Äthylenoxidherstellung \ to a value which is higher than the active samkeitswerte J that can, under normal conditions, obtained with corresponding catalysts, the same catalyst referred to, but with the exception that | these instead of a combination of a) and b) each; only the corresponding amount of a) or the corresponding-: de amount of b) contain “; II) treating the impregnated support to make at least a fraction of the silver salt metallic To convert silver and to cause the deposition of the silver or of a) and b) on the carrier. Method according to claim 9, characterized in that
the solvent or solubilizing agent is lactic acid, an amine, or an aqueous mixture of amines
is. 030040/0741 ORIGINAL INSPECTED 11. The method according to claim 9-10, characterized in that the impregnated carrier to a temperature of about 200 ° C to about 700 ° C is heated. 12. The method according to claim 9-11, characterized in that the alkali metal is sodium, lithium, potassium or rubidium is used. 13. The method according to claim 12, characterized in that the cesium and potassium salt in solution in one concentration is present, which is sufficient to cesium or potassium in a weight ratio of about 100: 1 to about 1: 100 to be deposited. ; 14. The method according to claim 9-13, characterized in that the amount of silver salt in solution is sufficient to of about 2 to about 20 wt .-%, preferably from about 6 to about 16 wt .-% of silver to be deposited on said carrier. 030040/0741