United States Patent [191
`Ritscher et a1.
`
`[54] THREE-WAY CATALYTIC PROCESS FOR
`GASEOUS STREAMS
`
`[75] Inventors: James S. Ritscher, Ossming; Michael
`R. Sandner, Chappaqua, both of NY.
`[73] Assigneea Union carbide Corporation, New
`,
`York, N_Y‘
`
`_
`
`_
`
`[21] AppL NO; 80,132
`_
`Sep. 28, 1979
`[22] Filed:
`'
`[51] Int. Cl.3 ............................................ .. B01D 53/36
`[52] US. Cl. ........ .; ....................... .. 423/21s.2; 60/301;
`423/239; 423/245; 423/247
`[58] Field of Search ................ .. 423/213.2, 213.5, 245,
`423/247; 60/301; 252/455 Z
`References Cited
`
`[56]
`
`U.S. PATENT DOCUMENTS
`3,346,328 10/1967 Sergeys .......................... .. 423/213.2
`
`[11]
`[45]
`
`4,297,328
`Oct. 27, 1981
`
`3,716,344 2/ 1973 Ashburn ......................... .. 423/213.2
`4,157,375 6/1979 Brown et a1. ..
`423/239
`4,170,571 10/1979 Ritscher .............. ..
`. 252/455 Z
`
`FOREIGN PATENT DOCUMENTS
`2263387 7/1973 Fed. Rep. of Germany 423/213.2
`2411853 9/1974 Fed. Rep. of Germany 423/213.2
`
`Primary Examiner—G. O. Peters
`Attorney, Agent, or Firm—Gary L. Warner
`
`ABST
`57
`RACT
`[
`]
`A processfor the catalytic combustion of carbon mon~
`oxide and hydrocarbons and the catalytic reduction of
`the oxides of nitrogen contained in a gas stream. The
`process involves intimately contacting the gaseous
`stream with a catalyst bed comprising copper metal or
`copper ion and a high silica zeolite.
`
`12 Claims, 1 Drawing Figure
`
`Umicore AG & Co. KG
`Exhibit 1113
`Page 1 of 10
`
`

`

`U.S. Patent
`
`Oct. 27, 1981
`
`4,297,328
`
`I80
`
`I40
`
`I20
`
`I00
`
`80
`
`FIG.
`
`0
`no
`8
`ON :IO NOISHHANOO %
`
`
`
`
`
`% EXCESS O2 OVER STOICHIOMETRIC OXIDANT
`
`Umicore AG & Co. KG
`Exhibit 1113
`Page 2 of 10
`
`

`

`1
`
`25
`
`.‘ THREE-WAY CATALYTIC PROCESS FOR
`-
`GASEOUS STREAMS.
`
`4,297,328
`2
`amount is provided. In addition, base metal catalysts
`may be used for the combustion of hydrocarbons if the
`‘operating temperature of the catalyst is raised suffi
`ciently.
`,
`FIELD OF THE INVENTION
`‘Although no catalyst is presently known for catalyz
`ing the disproportionation of NOx, a variety of catalysts
`This invention relates'to a process for the catalytic
`are known which reduce NO; to N1, using carbon mon
`oxidation of carbon monoxide and hydrocarbons and .
`oxide, hydrogen or hydrocarbons as the reductant.
`the reduction of nitrogen oxides contained in a gaseous
`Since all three of these reductants are present in normal
`stream. The, process may occur inva stoichiometric ex
`automobile emissions, this would appear-to be a simple
`cess of oxygen without substantial decrease in the con
`‘matter. Unfortunately, oxygen is also present in such
`version to non-noxious products.
`emissions and most catalysts which reduce NOX will not
`BACKGROUND OF THE INVENTION
`operate effectively, in an oxidizing atmosphere. Instead
`of reducing NOX the reductants reduce oxygen. In addi
`1 One of the most troubling pollution control problems
`today arises from the ‘emissions of automobiles. The
`tion, some of the noble metals used to oxidize carbon
`monoxide and hydrocarbons, ‘i.e., platinum and palla
`noxious emissions are of essentially three types. These
`are: (1) carbon monoxide (CO), (2) hydrocarbons (HC
`dium, tend to reduce NO,‘ to ammonia in a highly ef?
`cient manner. Since ammonia is highly noxious, its pro
`and (3) nitrogen oxides (NOX).
`.
`'
`"The simultaneous control of these various pollutants
`duction is undesirable. Thus, platinum and palladium
`20
`presents a formidable technical problem because of
`either alone or in combination, are not suitable for con
`varying nature of the pollutants. Control of carbon
`_ trolling the pollutant NOx. To avoid the production of
`monoxide and hydrocarbons is a relatively simple mat
`ammonia the catalyst may be chosen as either rhodium
`ter to achieve catalytically. The simultaneous control of
`or ruthenium, either alone or in combination, as both
`nitrogen oxides, carbon monoxide and hydrocarbons,
`efficiently catalyze the reduction of NO,‘ to N2. Unfor
`by a so-called “three-way” catalyst, is a much more
`tunately, the use of these catalysts create a number of
`difficult problem.
`problems.
`*The need to simultaneously control these three types
`Ruthenium tends to form volatile oxides in an even
`of pollutants has long been recognized. It has long been
`slightly oxidizing atmosphere and these oxides are then
`known that nitrogen oxides are both pollutants and
`distilled out of the catalytic system. In addition to the
`initiators for complex photochemical reactions with
`resulting loss in catalytic activity, ruthenium and its
`hydrocarbons. The resultant “photochemical smog” is a
`compounds are highly toxic. Therefore, from a practi
`serious problem. Carbon monoxide is a serious pollutant
`cal standpoint, only rhodium can be used for the reduc
`in and of itself.
`tion of NOx to nitrogen. Rhodium, however, does not
`Carbon monoxide is a relatively easy pollutant to
`function as a suitable catalyst when used in an even
`control and is easily combusted in a catalytic‘ unit to
`slightly oxidizing atmosphere. Thus, there must always
`carbon dioxide. Even under an oxygen-de?cient atmo
`be excess reductant present if rhodium is to be used.
`sphere, carbon monoxide will be combusted to the oxy
`Unfortunately, if too much reductant is present the
`gen limiting value by any noble metal, and many base
`reduction of NOX to ammonia on platinum or palladium
`metal, catalyst.
`occurs. As a result of these countervailing consider~
`The catalytic control of various “hydrocarbons” is
`ations, the conversion of NOx to nitrogen can be accom
`more dif?cult. The. combustion of hydrocarbons to
`plished by rhodium only over a narrow range of oxidant
`carbon dioxide and water varies in complexity depend
`and reductant, i.e., the oxidant/reductant ratio.
`ing on the nature of the hydrocarbon. The group re
`The above-noted oxidant/reductant ratio must be
`ferred to as “hydrocarbons” includes many different
`carefully controlled for the three presently known
`7 substrates, some being very reactive while others are
`“three way” catalyst systems, i.e. platinum/rhodium;
`highly refractory. This group also includes small
`platinum/ruthenium; and monel. The narrow range of
`amounts of hydrogen which is easily oxidized. A small
`oxidant/reductant, i.e.,-air/fuel, under which the cata
`amount of methane is included in this group, and is a
`lysts are operable is referred to as the “window” for the
`hydrocarbon which is relatively difficult to oxidize.
`catalyst and the overall effect is referred to as the “win
`Most “hydrocarbon” pollutants are considerably easier
`dow effect”. The stoichiometric ratio of air to fuel,
`to oxidize than methane, but since they only weakly
`referred to as the air/fuel ratio or A/F ratio, is depen
`chemisorb on catalytic surfaces, they are more dif?cult
`dent on the natureof the fuel. For the fuels commonly
`to oxidize than carbon monoxide and hydrogen.
`employed for automobiles it is preferably about 14.7.
`In general the nitrogen oxides troublesome from a
`When the A/F ratio is less than 14.7, the mixture is
`pollution standpoint are nitric oxide (NO) and nitrogen
`referred to as “rich", i.e., excess fuel is present in the
`dioxide (N02) and are both referred to herein by the
`mixture. When the A/F ratio is above 14.7 the mixture
`formula NOX. The elimination of NO,; is generally
`referred to as “lean”, i.e., excess air or oxygen is present
`achieved by the reduction of NO,‘ to elemental nitro~
`in the mixture. An A/F unit is simply a change in the
`gen. In theory, NO can be disproportionated to yield
`A/F ratio of 1.0.
`N2 and 02, since it is thermodynamically unstable with
`The three presently known “threeway” catalysts
`respect to its elements. Even so, there is no known
`referred to, above operate properly when the fuel mix
`catalyst for this disproportionation and absent such a
`ture is “rich” i.e. when the A/F ratio is less than 14.7
`catalyst it does not occur at an appreciable rate.
`and the environment is a reducing atmosphere. How
`The present means for oxidizing “hydrocarbons” and
`ever, if the A/F ratio is much less than about 14.7 unac
`carbon monoxide is by use of noble metal catalysts in
`ceptable levels of carbon monoxide and hydrocarbons
`the presence of suf?cient oxygen for complete combus
`pass through the catalyst unoxidized. The limits, i.e. the
`tion. In practice, this requires a slight excess of oxygen
`range of A/F values, under which the catalysts effec
`such that an amount in excess of the‘stoichiometric
`
`35
`
`40
`
`45
`
`50
`
`55
`
`65
`
`Umicore AG & Co. KG
`Exhibit 1113
`Page 3 of 10
`
`

`

`4,297,328
`3
`tively control all three pollutants, i.e., the “window”, is
`between 14.4 and 14.7. When the 'A/F ratio moves
`outside these values the catalyst performance and'there
`fore, the control of pollutants dramatically decreases.
`Further, below an A/F ratio of about l4.4,'theforma
`tion of ammonia on the platinum catalyst becomes ‘a
`
`signi?cant problem. .
`
`.
`
`n
`
`.
`
`I
`
`>
`
`.
`
`‘
`
`less; -
`
`»
`
`,
`
`..
`
`1n addition,'the use of high-silica zeolites for the
`adosrption/combustion of an organic-substrate is dis
`closed .in ‘co-pending U.S. application‘ Ser. -No.- 053,149
`filed June 29, 1979.
`I ’
`-
`This co-pending application discloses another impor
`tant'characteristic of thesehigh-silica zeolites, that is,
`their ability to adsorb anv organic substrate, i.e. organic
`compounds, ‘until the organic substratexis catalytically
`acted upon. Inthe particularcase of any gaseous exhaust
`stream, this characteristic provides a meansof?capturing
`and'storing the organic- substrate fromthe gaseous
`stream while the temperature of the stream is raised to
`the optimum temperature required for the vcatalytic
`
`process.
`
`"
`
`>
`
`‘
`
`'
`
`2
`
`-
`
`.
`
`4
`to about 2.0 A/F units. Further, such a catalyst should
`operate ef?ciently in an oxidizing atmosphere",v i:e., on
`the “lean” side of the air/fuel ‘mixture wherein the A/F
`ratio is greater than about 14.7.
`Further, it has been suggested that the'oxides of nitro
`gen may be, reduced. by use of a zeolite exchanged
`against a catalytically active metal when said reduction
`Further, although “monel” is referred to as a “three
`is performed inthe presence of an ef?cient: amount of
`Way” catalyst this characterization of monel is a, poor
`carbon monoxideand/or hydrogen. Such a] process is
`one. While the platinum/rhodium and platinum/rm
`\disclosed in Disclosure. Publication 2,411,853 of the
`thenium catalysts exhibitsigni?cant oxidizing activity
`German Federal Republic,——corresponding U.S. Appli
`“monel” exhibits relatively poor oxidizing activity.
`cation, Ser. No. 340,809_—¢wherein oxides of nitrogen
`“Monel” is also structurally unstable in a cycling envi
`are reduced in an exhaust gas comprising not‘ more than
`ronment, i.e., if the A/F ratio changes from rich to lean
`2% oxygen. The German disclosure has as arequire
`and back, as, is often the case, and under this environ
`ment that no more than 2% oxygen ever be present in
`ment the catalyst deteriorates rapidly. “Monel” is also
`the exhaust gasi,undergoingtreatment. In- addition, the
`easily poisoned by sulfur which is present in small
`disclosed process does not utilize the novel features of
`amounts in motor fuels.
`high-silica zeolites but instead utilizes zeolites such as
`Further, the ef?cientvuse of the known “three-way”
`mordenite, zeolite Y or natural-zeolites such as faujasite,
`catalysts requires the constant maintenance of an air .to_
`chabazite and erionite. Further, the disclosed process
`20
`fuel ratio within 0.3 A/ F units of a certain air/fuel ratio
`must use- a nickel exchanged. zeolite to‘ minimize the
`value, as determined by the particular fuel. Unfortu
`production of ammonia. Further, the disclosedprocess
`nately, even modern carburetors cannot control the
`requires thatthe amount of oxidizing gases must not be
`A/F‘ratio ‘to within
`A/F ‘units. Therefore, the ex
`so large as to consume all reducing-gas beforev the re
`haust stream is constantly shifting outside the accept-.
`duction of the oxides and nitrogen. Thus,‘ the process
`25
`able A/F ratio for ef?cient use of the catalyst. Further,‘v
`requires that less than stoichiometric amounts of oxidiz
`ing_gases,e.g.-, oxygen, be present and, as speci?cally
`the ‘mixture must still be operated on a “rich” mixture
`which gives inherently poor fuel economy.
`.
`claimed, the concentration of oxygen must be 2% or
`To circumvent the problems associated with the ‘pres
`ently'known “three-way” catalysts various engineering
`techniques may be employed. The use of an oxygen
`sensor connected in a feedback loop to a micropro‘ces-t
`sor, whereby the carburetor is controlled, is perhaps
`one of the better suggested methods. Unfortunately, this
`technique greatly increases the complexity and cost of
`35
`the carburetion system and the carburetor must still
`operate on the “rich” side of the air/fuel mixture whichv
`inherently lessens fuel economy. Alternatively, a two-'
`stage system may beemployed wherein a ?rst reducing
`stage is followed by the introduction of excess air and a‘
`second oxidizing stage. Unfortunately, this technique
`also increases the complexity and 'cost of the carbure
`tion system and must also be operated on the “rich” side'
`of the'air/fuel ‘mixture.
`I
`‘
`i‘
`A further catalyst system is known to the prior art
`45
`which although not generally thought of as a “three-v
`way” catalyst does exhibit some “three-way” activity.
`This catalyst comprises an'iridium-based catalyst and
`employes ‘a two-stage catalyst ‘system. The catalyst
`system has poor oxidizing activity, but has the advan
`tage of operating efficiently in an oxidizing atmosphere,
`i.e., on a “lean” air/fuel mixture: Furthermore, the
`“window” for which the catalyst 'operates ef?ciently,
`i.e. as a three-way catalyst, is narrow,‘ although larger
`than the three previously discussed, and beyond another
`0.3 A/ F units the NOX reduction is relatively poor. 9
`The above-noted catalysts all have ai'further inherent
`disadvantage. Each catalyst employs a noble metal sys
`tem or iridium. These metals areextremely scarce and
`expensive. In particular, the scarcity and expense of
`60
`rhodium, the preferred reduction catalyst, raises serious
`questions over its continued use as a catalyst -for'au'to-"
`mobile emissions. In fact, the price-of rhodium has more
`than‘doubled since 1975 and is presently about $800.00
`per troy ounce.
`‘
`"
`A preferred “three-way” catalyst would minimize the
`problems of presently known catalysts." Such a pre
`ferred catalyst should operate over an A/F range of up
`
`Further, the use of a metal containing high-silica
`zeolite catalyst is disclosed in co-pending U.S. Ser. No.
`865,125,'filed Dec. 28, 1977. US. Ser. No. 865,125 dis‘
`closes a process for producing carbon dioxide by the
`conversion of hydrocarbons and carbon monoxidein a
`gas stream in admixture with oxygen and water vapor
`wherein said vgas stream is ‘contacted with a metal cori
`50.
`ta'in'ing crystalline zeolite aluminosilicate. The metal is‘
`chosen-from! Group‘ VIII metals. The'catalyst of this
`co-pending application may-‘also promote the conver
`sion of nitric oxide to nitrogen when the gas stream is
`suf?ciently low in oxygen such‘ thatvthe gas‘stream ‘is
`essentially neutral or is reducing in the redox sense.
`- The present invention provides a “three-way” cata
`lyst having advantages beyond those disclosed in the
`
`55
`
`prior‘art. ‘
`
`.
`
`'
`
`‘
`
`'
`
`'
`
`-
`
`The ‘present invention :provides a “three-way” cata
`lyst that is relatively inexpensive in that it employs the‘
`use of a base'metal, rather‘than a noble metal.‘
`'
`Further, the present invention provides a “three
`wa'y”'catalyst which effectively controls emissions of
`carbon monoxidev and hydrocarbons and provides a
`“three-way” catalyst wherein'oxides of - nitrogen are
`reduced preferentially‘to Nz'over a 'A/ F ratio range of
`up'to about 2.0 units.‘
`-
`'
`
`65
`
`Umicore AG & Co. KG
`Exhibit 1113
`Page 4 of 10
`
`

`

`4,297,328
`6
`5
`Further, the present invention provides a “three
`silica zeolite framework. As will be evident from the
`way” catalyst which effectively converts oxides of ni
`nature of the process and from the following examples,
`trogen to nitrogen without the production of signi?cant
`any zeolite or zeolite-like material having a SiO2/Al2O3
`amounts of ammonia, even in the absence of oxygen and
`molar ratio which exceeds about 10 and having the
`with an stoichiometric excess of hydrocarbon.
`characteristics of these high-silica zeolites will function
`Further, the present invention provides a “three
`as the zeolite used herein. However, in order to achieve
`way” catalyst that is thermally stable under the condi
`the most desirable results, the particular zeolite used
`tions of oxidation and reduction and is stable in an envi
`herein should preferably have certain additional charac
`ronment that cycles from “rich” to “lean” air/fuel mix
`teristics, as follows:
`Firstly, the zeolite should be metal ion-exchanged,
`-doped, or loaded suf?ciently so as to provide an effi
`cient amount of catalytic metal within or on the zeolite.
`Secondly, the zeolite should be thermally stable and
`in addition, be thermally stable in the presence of steam;
`that is, it should have thermal and hydrothermal stabil
`ity at the temperatures at which the catalytic process
`occurs. Typically a thermal and hydrothermal stability
`of at least about 600° C. is suitable for the present inven
`tion although this value depends on the nature of the
`gaseous stream being combusted and the chosen process
`parameters, e.g. flow rate, reaction time, water content
`and operating temperatures.
`In general, any zeolite, a crystalline material having
`an intracrystalline void volume, having a silica to alu
`mina ratio greater than 10, preferably greater than 20,
`will be found to perform satisfactorily as the zeolite for
`forming the metal-containing high-silica zeolite.
`Representative of those high-silica zeolites having the
`above-identi?ed properties, but not limited thereto, are
`“silicalite”, ZSM-S, ZSM-8, ZSM-ll, ZSM-12, Hyper
`Y, ultrastabilized Y, hereinafter designated “ultra-Y”,
`Beta, mordenite and erionite. It is to be understood that
`other zeolites having the properties described herein
`may be used without departing from the scope of the
`present invention. “silicalite” is a novel crystalline sil
`ica composition having a hydrophobic/organophilic
`characteristic which permits its use for selectively ad
`sorbing organic materials preferentially to water. Silica
`lite is more completely described in U.S. Pat. No.
`4,061,724, assigned to Union Carbide Corporation. It is
`described in claim 1 of said patent as, “A silica poly
`morph consisting of crystalline silica, said silica poly
`morph after calcination in air at 600° C. for 1 hour,
`having a mean refractive index of 1.39:0.01 and a
`speci?c gravity at 25° C. of 1.70:0.05 g./cc.” and in
`claim 2 as, “A silica polymorph consisting of crystalline
`silica, said silica- polymorph after calcination in air at
`600° C. for 1 hour having as the six strongest d-values of
`its X-ray powder diffraction pattern those set forth in
`Table A.”
`Table A is as follows:
`TABLE A
`Relative Intensity”
`
`tures.
`
`‘
`
`Finally, the present invention provides a “three-way”
`catalyst that is easily prepared, stable to handle and is
`virtually nontoxic.
`The instant invention provies a “three-way” catalyst
`having the above characteristics and overcomes the
`difficulties of the prior art by utilizing the unusual and
`unexpected behavior of catalysts which employ the use
`of high-silica zeolites. It has been found that copper
`containing high-silica zeolites provide a catalytic sys
`tem for the simultaneous oxidation of carbon monoxide
`and hydrocarbons to essentially carbon dioxide and
`water and for the reduction of oxides of nitrogen to
`nitrogen.
`The instant invention is more fully discussed hereinaf
`ter in the detailed description of the invention.
`
`DETAILED DESCRIPTION OF THE
`INVENTION
`The process of the present invention overcomes the
`problems associated with those “three-way catalysts”
`known to the prior art by utilizing the unique behavior
`of copper-containing high-silica zeolites.
`The novel “three-way” catalyst and process of the
`invention utilize the unusual properties of high-silica
`zeolites, i.e. those having a Slog/A1203 molar ratio
`which exceeds about 10 and preferably about 20. It has
`been found that these high-silica zeolites are organo
`philic and hydrophobic, and may be utilized to oxidize
`carbon monoxide and hydrocarbons and reduce oxides
`of nitrogen when they contain copper metal or copper
`metal ions.
`It has been found that these high-silica zeolites, unlike
`’ the aluminas, maintain a relatively high adsorption ca
`pacity even at a temperature of 200° C. This behavior is
`to be distinguished from that of conventional zeolites,
`e.g. Zeolite A, U.S. Pat. No. 2,882,243; Zeolite X, U.S.
`Pat. No. 2,882,244; and Zeolite Y, U.S. Pat. No.
`3,216,789; which tend to strongly adsorb water and
`only weakly adsorb an- organic substrate. In addition,
`the thermal and hydrothermal stabilities of these high
`silica zeolites are often hundreds of degrees Centigrade
`higher than those of conventional zeolites, i.e. in excess
`of 800° C.
`The above-mentioned high-silica zeolites may be used
`so as to form “three-way” catalysts whichcircumvent
`most of the problems associated with the previously
`discussed catalysts. The “three-way” catalyst used
`herein is prepared by introducing the metal into the
`framework of the high-silica zeolite to form a copper
`containing high silica zeolite which exhibits both unique
`adsorption and catalytic characteristics when used in
`combination with a catalytic metal. Because these high
`silica zeolites have the capacity to undergo ion-ex
`change, the catalytic metal or metal ion may be conve
`niently introduced directly into the zeolite framework.
`The copper-containing high-silica zeolites, i.e. three
`way catalysts, of the present invention are prepared by
`introducing copper metal or copper ions into the high
`
`l0
`
`15
`
`25
`
`30
`
`35
`
`40
`
`45
`
`50
`
`55
`
`d-A
`
`11.1 i 0.20
`10.0 i 0.20
`3.85 i 0.07
`3.82 i 0.07
`3.76 i 0.05
`3.72 i‘ 0.05
`
`"VS = Very Strong: S : Strong
`
`VS
`VS
`VS
`S
`S
`5
`
`The preparation of silicalite is set forth in Examples 3,
`5, 6 and 7, of U.S. Pat. No. 4,06l,724, which examples
`are incorporated herein by reference.
`The above-mentioned ZSM-type zeolites are de
`scribed in various U.S. Patents and Foreign Patents as
`follows:
`
`60
`
`65
`
`Umicore AG & Co. KG
`Exhibit 1113
`Page 5 of 10
`
`

`

`4,297,328
`7
`ZSM-5 is a crystalline zeolite and is disclosed in U.S.
`Pat. No. 3,702,886. The preparation of ZSM-5 is set
`forth in Examples 1, 2, 6, 22, 26 and 27 of U.S. _Pat. No.
`3,702,886, which examples are incorporated herein by
`reference.
`I
`ZSM-8 is a crystalline zeolite and is disclosed in Brit
`ish speci?cation No. 1,334,243, published Oct. 17, 1973.
`ZSM-ll is a crystalline zeolite and is disclosed in U.S.
`Pat. No. 3,709,979.
`The preparation of ZSM-ll is set forth in Examples 1,
`2, 4, 5, 8 and 10 of U.S. Pat. No. 3,709,979, which exam
`ples are incorporated herein by reference.
`ZSM-12 is a crystalline zeolite and is disclosed in U.S.
`Pat. No. 3,832,449. The preparation of ZSM-12 is set
`forth in Examples I, II, III, IV, V, VI, VII and VIII of
`U.S. Pat. No. 3,832,449, which examples are incorpo
`rated herein by reference.
`U.S. Pat. Nos. 3,702,886 (ZSM-5), 3,709,979 (ZSM
`ll), and 3,832,449 (ZSM-l2) are commonly assigned to
`Mobil Oil Corporation, New York, New York.
`Ultrastabilized Y, i.e. ultrastabilized form of zeolite
`Y, is a form of zeolite Y which has been treated to give
`it the organophilic characteristic of the adsorbents of
`the present invention. A description of ultrastabilized Y
`is found in “Crystal Structures of Ultrastable Fauja
`sites”, Advances in Chemistry Series, No. 101, Ameri
`can Chemical Society, Washington, D.C., pages
`266-278 (1971).
`In addition to the above-mentioned high-silica zeo
`lites, a particularly well suited high-silica zeolite, the
`zeolite used in the illustrative examples of the present
`invention, is the class of high-silica zeolites designated
`and hereinafter referred to as the Support A.
`Support A comprises a class of zeolites, described
`more fully in co-pending U.S.P. application Ser. No.
`655,065, ?led Feb. 4, 1976, said class of zeolites compris
`ing zeolite compositions which are readily composed by
`preparing an organic-free reaction mixture. These zeo
`lite compositions are highly siliceous and can contain an
`extraordinarily high amount of divalent metal cations.
`Further, the high thermal and hydrothermal stabilities
`of these zeolite compositions, i.e. in excess of 600° C.,
`make them ideally suited for the instant process.
`The Support A compositions, abbreviated hereinafter
`as SA, exhibit an aluminosilicate crystal structure
`wherein at least some of the 'AlO4— tetrahedra thereof
`are associated with, i.e. electrovalently neturalized by, a
`metal cation.
`The composition of these zeolites in the dehydrated
`state can be expressed empirically in terms of moles of
`oxides as follows:
`
`8
`TABLE I
`Interplanar Spacing, d (A)
`
`11.1 i" 0.2
`10.1 i 0.2
`3.85 i 0.07
`3.74 i 0.05
`3.72 i 0.05
`
`These values were determined by standard techniques.
`The radiation was the K-alpha doublet of copper, and a
`scintillation-counter spectrometer with a strip-chart pen
`recorder was used. The peak heights and the peak or
`line position as a function of two times theta (6), where
`theta is the Bragg Angle, were read from the spectrom
`eter chart. From these, the relative intensities and d
`(observed), the interplanar spacing in A, corresponding
`to the recorded lines, were determined.
`Ion-exchange of the original cations by other cation
`species does not substantially alter the X-ray pattern of
`Support A, but some minor shifts in interplanar spacing
`and variations in relative intensity can occur. Other
`minor variations can occur depending on the silica-to
`alumina ratio of the particular sample and whether or
`not the sample had been subjected to elevated tempera
`tures. In any event the d-spacings of the X-ray pattern
`will be within the tolerance indicated in Table 1.
`In conjunction with the aforesaid chemical composi
`tion and X-ray powder diffraction pattern, the SA com
`positions exhibit certain distinguishing infrared absorp
`tion characteristics. Infrared analytical techniques are
`recognized as highly useful in the study of ‘crystalline
`zeolites; see for example U.S. Pat. Nos. 3,506,400 and
`3,591,488 to Eberly et al., issued Apr. 14, 1970 and July
`6, 1971, respectively, and E. M. Flanigen, H. Khatami
`and H. A. Szymanski, “Adv. Chem. Series”., Vol. 101,
`1971 (pg. 201 et seq.).
`Infrared analysis was also employed to characterize
`these siliceous zeolites. Spectra were obtained on a
`Perkin-Elmer Model 112 single-beam instrument for the
`hydroxylstretching region 3800-3000 cm—1, on a Per
`kin-Elmer Model 621 double-beam instrument for both
`the mid-infrared region 1600-1300 cm—1 and the frame
`work region 1300-3000 cm— 1. After calcination at 600°
`C. in air, the samples were run as self-supported wafers
`(20 mg), and the spectra in the hydroxyl-stretching
`region were obtained after thermal treatments at 200° C.
`in vacuum for two hours.
`The process of the invention utilizes these metal-con
`taining high-silica zeolite compositions which include
`“3-way” catalysts comprising Support A with copper
`metal or copper ions. These catalysts are hereinafter
`designated by the abbreviations Cu-SA, wherein this
`abbreviation designates metal or metal ions of Cu intro~
`duced directly into the framework of Support A. This
`“3-way” catalyst is used to illustrate the process of the
`invention. Cu-ultra-Y is also a preferred “three-way”
`catalyst. In addition, the ZSM-5 type zeolites i.e. ZSM
`5, ZSM-8, ZSM-ll and ZSM-l2, hereinbefore de
`scribed, are preferred catalysts when in an appropri
`ately metal-containing form, i.e. when copper metal or
`copper ions are introduced into the framework of these
`high-silica zeolites.
`In order to more easily describe the conditions under
`which the instant process is carried out in the illustra
`tive examples hereinafter, the rate at which the gaseous
`stream passes through the catalyst bed is expressed by
`reference to the “space velocity”. The space velocity
`
`40
`
`45
`
`50
`
`0.01-2.0 M2/,,O: A1203: 20-100 SiOg
`wherein M represents a metallic cation and n represents
`the valence of M as prepared from reaction mixtures
`free of organic cations, as hereinafter described.
`These zeolites may also be .exchanged with ammo
`nium, or other cations, including metal ions, hydrogen
`ions, rare earth ions and mixtures thereof by contacting
`the zeolite with solutions containing one or more of the
`desired cations.
`In conjunction with the aforesaid chemical composi
`tion, these zeolites, i.e. SA compositions, possess a dis
`tinguishing crystalline structure characterized by an
`X-ray powder diffraction pattern having at least the
`following interplanar spacings:
`
`55
`
`65
`
`Umicore AG & Co. KG
`Exhibit 1113
`Page 6 of 10
`
`

`

`4,297,328 I
`:9
`10
`(SV) is de?ned as the volume of gas (V) passing through
`zeolite having a characteristic X-ray powder diffraction
`a given volume of catalyst space (Vc) divided by the
`pattern‘containing at least the d-spacings of Table l.
`catalyst space (Vc),i.e. SV=V/Vc. A space velocity of
`The product ?lter cake of the above zeolite is made
`10,000 hr-l means that the quotient of ,V /V c is equal to
`up into 5 inch pellets by blending the ?lter cake with
`10,000.
`acid-peptized alumina, in a weight ratio of 80 parts of
`anhydrous zeolite product to 20 parts alumina, and
`extruding this blended mixture. The extruded pellets are
`’ calcined for 2 hours at 600° C. The above-prepared
`high-silica zeolite is determined to be the high-silica
`zeolite previously designated as Support A.
`One hundred grams of the Support A pellets are
`added to a freshly ?ltered copper (II) chloride hydrate
`solution, prepared by dissolving 107.2 g. of the copper
`(II) chloride hydrate in 2000 milliliters of distilled wa
`ter. The solution and Support A pellets are gently re
`. ?uxed for three hours at which time the supernatant is
`decanted off. This process is repeated two additional
`‘times, for a total of three, and then the pellets are
`washed at room temperature for 1 hour with 2000 milli
`liters of distilled water with an occasional gentle swirl
`ing. The ?ltered pellets are then dried at .100" C. This
`catalyst is the catalyst previously designated as and is
`herein designated as catalyst Cu-SA. The catalyst
`Cu-SA pellets are activated by passing a stream of air
`containing 16 mole percent N02 at temperatures from
`25° C. to 250° C. over the catalyst pellets for a period of
`1 hour, followed by 1 hour at 350° C. in an air purge.
`Chemical analysis of a sample of this catalyst indicates
`that 7.3% copper, by weight, is present.
`
`25
`
`35
`
`45
`
`._
`Gas Flow Apparatus
`In carrying out the process of the invention a gas
`?ow, apparatus is used wherein a reaction container is .
`formed from apyrex oven comprising a pyrex container
`having nichrome wire wrapped around it for heating.
`The particular pyrex oven used in the examples set
`forth hereinafter, comprises an. inner‘pyrex tube (25
`mm.) placed within an outer pyrex tube wherein ap- ‘
`proximately 2 mm. separates the inner and outer‘ tubes.
`The inner tube is wrapped with nichrome wire, by
`which the reaction container is'heated and two side arm
`tubes extend from the inner tube. The side arm tubes are]
`spaced approximately 12cm apart and enable the intro
`duction of the influent stream and removal of effluent
`stream. A thermowell unit, comprising a 4 mm tube, is
`placed at approximately the middle of the inner tube
`wherein a thermocouple is placed, by means of which
`the temperature of the reaction container may be moni
`tored and controlled.
`‘
`'
`it By means of the nichrome wire heater the tempera
`tures of the catalyst bed region and a preheat region,
`comprising quartz chips, are maintained at the desired
`reaction temperature. After reaction the ef?uent
`stream, comprising essentially carbon dioxide, water
`and nitrogen exit the reaction container via one of the
`side arm members and is monitoredby means of a C02
`infrared analyzer and/ or a vapor