CA2079495A1

CA2079495A1 - Smoking article with co oxidation catalyst

Info

Publication number: CA2079495A1
Application number: CA002079495A
Authority: CA
Inventors: John H. Kolts; Scott H. Brown; Otis E. Helm; Timothy P. Harper
Original assignee: Individual
Current assignee: Phillips Petroleum Co
Priority date: 1991-10-03
Filing date: 1992-09-30
Publication date: 1993-04-04
Also published as: TW216767B; EP0535695A2; JPH05329213A; EP0535695A3

Abstract

Abstract of the Disclosure The present invention relates to a cigarette-like smoking article which is capable of producing substantial quantities of aerosol, both initially and over the useful life of the product, without significant thermal degradation of the aerosol former and without the presence of substantial pyrolysis or incomplete combustion products or sidestream aerosol.
Embodiments of the present smoking article comprise a combustible fuel element, a physically separate CO oxidation catalyst attached adjacent to the fuel element, a physically separate aerosol-generating means including an aerosol forming material attached adjacent to the catalyst in conductive heat exchange relationship with the fuel element, and a means for delivering the generated aerosol to the user.
The articles of the present invention provide the user with the taste, feel, and aroma associated with the smoking of conventional cigarettes without burning tobacco. The CO oxidation catalyst substantially decreases the level of CO inhaled by the user of such an article, by oxidizing the CO created by the burning fuel element to CO2.

Description

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_ OKING ARTICLE WITH CO OXIDATION CATALYST

Background of -the Inventio Th~ prqsen-t lnvention relates generally to smoking flrticles, and more particularly, bu-t not by way of lim:Ltation, to smoking articles comprising means for oxidation of CO.
Smoking articles have been disclosed which employ an ~` aerosol-producing apparatus to simula-te tobacco smoke. Generally, such articles comprise a small, hlgh density combustible fuel element in conjunction with a physically separate aerosol-generating means.
Generally, a heat conducting Member is utilized, such a8 a metal conductor, which contacts both the fuel elemen-t and a~rosol-generating means to transfer heat from the burning fuel element to the aerosol-generating means.
A problem with these articles is the high level of carbon monoxide which exists in the aerosol. This large amount of carbon monoxide is a result of incomplete combustion, which is caused by the burning carbonaceous fuel element. The level of carbon monoxide in the smoke of cigarettes and cigarette subs-titutes is a known concern in the tobacco industry.
Summary of the Invention It is an object of this invention to provide a product, such as, for example, a smoking article which is capable of producing substantial quantities of aerosol, both initially and over the useful ' :

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liEe of thH product, while also producing signlflcantly reduced quantities of carbon monQxide.
It is a further object of this lnvention to reduce potentlal health hazards in smoking.
In accordance with this invsntion there :Ls provided an apparatus for producing aerosol comprising fl combustible fusl element, a quan-tity of CO oxidation catalyst, and aerosol-generatlng means. In accordance with another aspect of this :lnventlon there is provided a cigarette-type smoking artlcle comprising a combustible hlel element, a quantity of C0 oxidatlorl catalyst, aerosol-generatlng means, and means for dellvering the generated aerosol to the user.
The present invention is described in greater detai1 in the accompanying drawings and :Ln the detailed descrip-tion of the invention which follow.
_ief Description of the Drawin~
Figure l ls a longitudinal cross-sectional view of a smoking article constructed in accordance with the invention.
Figure 2 is an enlarged, partlal left side elevation view of the smoking article of Figure l more clearly illustrating the preferred fuel element passageway configura-tions.
Figure 3 is an elevation view similar to Figure 2 illustrating a second fuel element passageway conflguration.
Figure 4 is an elevation view similar to Figure 2 illustrating a third fuel element passageway configuration.
Figure 5 is a longitudinal cross-sectional view of a smoking article constructed in accordanca with a second embodiment of the inven-tion.
Figure 6 ls a longitudinal cross-sectional view of a smoking article constructed in accordance with a third embodiment of the lnventlon.
Figure 7 is an enlarged partial longitud:inal cross-sectional view more clearly illustrating the aerosol-production assembly employed in the embodiments of Figure l, Figure 5 and Figure 6.

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3 21~79~95 Flgllre R :ls Rn enlnrged eleva-tion vlew taken along llne 8-8 of Figur~ 7.
Figure 9 is an enlarged longitudinal cross-sectlonal view of An alternative for~ of metallic contalners suitable for use in the Assembly of Figure 7.
Flgure 10 is a cross-sectional view taken along line 10-10 of Figure 9.
Figure 11 Ls an enlarged partial longitudinal cross-sectional view illustrating an al-ternative form of aerosol-production assembly suitable for employment in the embodiments of Figure 1 and Flgure 5.
Figure 12 is an enlarged cross-sectional view taken along line 12-12 of Figure 11.
Figure t3 is an enlarged elevfltion view takan along line 13-13 of Flgure 11.
Flgure 14 ls an enlarged longitudinal cross-sectional view of an nlterna-tive form of metallic catalyst container suitable for use in the assembly of Figure 11.
Figure 15 is a cross-sectional vlew taken along line 15-15 of Figure 14.
Detailed Description of the Inventlon Referring now ~o the drawlngs, and to Flgure 1 ln particular, there ls lllustrated a clgarette-like smoklng artlcle 10 constructed in ac&ordance with one embodiment of the present inventlon. The smoking article 10 includes an aerosol produc~tlon assembly 12 comprlsing a heat-conduc-tive tubular metfll container 14 having a partially closed, perforated first end portion 16~and an open second end portion 18J a combustlble fuel element 20 fixedly secured in the second end portion 18, a quantity of C0 oxidation catalyst 22 disposed within the metal container 14 adjacent to the fuel element 20j and a quantity of aerosol-generatlng material 24 disposed within the metal container 14 intermediate the first end portion 16 and the catalys-t 22.
A C0 oxidation catalyst can be any catalyst capable of the oxidation of carbon monoxide to carbon dloxide by reaction with oxygen.
The process for oxidlzing a carbon ~onoxide containing gas can be .

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carrled out at Any suitable temperature and pressure conditions and any suitable volume ratio oE C0 an 2~
Th~ perlphery oE the ~uel element 20 is surrou}lded by a porous jacket of rcsiliellt heat insulating fibers 26, such flS glass fibers.
The portion oE the tubu]ar metal contain~r 14 contailling the catalyst 22 and aerosol-generating materia] 24 is surxounded by ~ jacket of tobacco-containing material 30. At the first end portion 16 oE the container 14 is situated a tobacco paper filter 32 having a Eirst end 34 contacting the first end portion 16 and the tobacco 30 and an opposlte second end portion 36. At the second end portlon 36 of the tohacco paper fllter 32J a porous fllter elenlent 38 having A ftrst ~nd portLon 40 contactlll~ the second end portLon 36 nncl hav:Ltlg an opposlte second end port:lon ~2 def:LnLng the terminnl or mouth-end of the smok:Lng artlcLe 10. The entire length of the smoking artlcle 10 ls overwrapped with one or more layers of a sui-table combustible wrapper 44 such as, for example, cigarette paper.
Preferably, the fuel elemQnt 20 is provlded with one or more longitudlnally extendlng passageways 46. The passageways 46 provide means for controlllng transfer of heat from the fuel element 20 to the aerosol-generating material 24, which is important both in terms of transferring enough heat to produce sufficient aerosol and in terms of avoiding the transfer of so much heat that the aerosol-generating ma-terial 24 is degraded. Generally the passageways 46 provide porosity - ' and increase early heat transfer to the aerosol-generating material 24 by increasing the amoun-t of hot gases which reach the aerosol-generating , material 24. The passageways 46 also tend to control *he rate of burning of the fuel element 20.
~`Generally, a large number of passageways 46, e.g. about 5 to 9 or more, especially with fl relatively close spacing between the passageways such that the passages grow together~ at least at the lighting end 48 of *he fuel elemen-t 20, during burning and produce high convective heat transfer which leads to high aerosol delivery from aerosol-generating material 24. A large number of passageways 46 also generally helps assure ease of lighting of the fuel element 20.

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s Figure 2, Fi&ure 3 J and Fignre 4 show sev~rfll suitable alternativ~
configurfltions for such pflssageways 46.
The most pr~ferred fuel elements 20 useflll in pr~cticing -this invention flre cflrbonflceous mflteriflls (i.e. ma-terials prlmarily comprising carbon). Combustible fuel elements 20 collstructed of carbonflceous materials are partLcularly fldvantflgeous because they produce minimal ash, and h~ve high heat generatillg capacity.
A preferred combustlble fuel element 20 iæ formed of a pressed or extruded mflss oE carbon preparecl from a powd~recl carbon and bLndcr, by conv~ntional press~lr~ Eormlng or cxtrllsion technl~ues. Sllltflble non-actlvfltod carbons for pressure EormlnK ar0 preparccl from pyrroll~ed cotton or pyrrolized papers, such as non-talc containing grades of Grande Prairle Canadian Kraft Paperl available from the Buckeye Cellulose Corporation of Memphis, Tennessee. A suitable activated caxbon for combustible Euel elements 20 is sold under the designation PCB-G, and another suitable non-activated carbon is sold under the designation PXC, both of which are available from Calgon Carbon Corporation, Pittsburgh3 Pennsylvania.
A suitable carbonacaous fuel cfln be prepared by admixing from about 50 to about 90 weight-%, most praferably from 80 to 95 weight-%, of the carbonaceous material based on the total weight of carbonaceous material and binder with from about 1 to about 50 weight-%, most preferably from 5 to 20 weight-%, of a sultable binder based on the total weight of carbonaceous material and binder with sufficient water to make a paste having a stiff dough~like consistency. Minor amounts 3 e.g. up to flbout 35 weight-%, preferably from flbout 10 to abou-t 20 weight-%, based on the total weight of carbonaceous materifll and binder, of tobflcco, tobacco extract, and the like can be added to the paste with additional water, if necessary, to maintain a stiff dough-]ike consistency.
The paste is then extruded, using any suitable ex-trusion apparatus such as a conventional ram or piston type extruder, into the desired shape with the desired number and configuration of passageways, and dried, prrferably at a te~per:ture iA the r:n8e Oe fro~ about 90C

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6 ~ 3 to flbout lOOC to redllce the mois-ture conten-t to about 2% to 7% by weight bflsed on the total weight of paste. Alternatively, the passageways can be formed using conventionfll drilling t~chniques.
In ge.neral, -the combus-tible fuel elements 20 which are employed in practicing the invention are less than about 20 mlllimeters long. Preferably, the element 20 is about lS millimeters or less, more preferflbly about 10 millimeters or less in length. Advantageously, the diameter of the fuel element 20 is flbout 8 millimeters or less, preferably between about 3 and 7 m:Llllmeters, and more preferably between about 4 to 6 millimeters. The density of the cflrbonaceous material forming the fuel elements 20 ranges generally from about 0.5 g/cc to about 1.5 g/cc as measured, e.g., by mercury displacement.
Preferably, the dens:lty is greater than 0.7 g/cc, more preferably greater than 0.8 g/cc. The length and diameter of the fuel element 20, the dens:Lty of the carbonaceous material Erom which it i9 formed, and the passageway patterns aro selected to achieve a desired burning time for the fuel element 20. In most cases, a high density carbonaceous material is desired because it helps to ensure that the fu~l element will burn long enough to slmulate the burning time of a conven-tional cigarette and that it will provide sufficient heat energy to generate the required amount of aerosol from the aerosol-generating material 24.
Upon lighting the smoking article 10, the fuel element 20 burns, generating the heat used to volatize the components of the aerosol-generating ma-terial 24. These thus vola-tized components comprise the aerosol and are then drawn through the mou-th-end 42 of the smoking article 10, especially during puffing, and into the users mouth, in a manner akin to the smoking of a conventional cigarette.
The aerosol-generating material 24 preferably includes one or more thermally stable components which carry one or more aerosol-forming substances. As used herein, a "thermally s-table" material is defined as one capable of withstanding the high, albeit controlled, -temperatures, e.g., generally from about 350C to about 600C, which may eventually exist near the burning iuel element 20, without significant ~' :
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decomposit:ion or burn:lng. Th~ use oE such thermally stable materi~l is believed to help maintain the simple "smoke" chemistry of -the aerosol.
S~itable aerosol-forming substances include polyhydri.c fllcohols and mixtures of polyhydr:Lc alcohols. PreEerred aerosol-forming substances are selected from -the group conslsting of glycerin, triethylene glycol, propylene glycol, and mixtures o:~ any two or more thereof.
One particularly preferred aerosol-generat:Lng material 24 comprises a thermally stable alumina substrate conta:LnIng sprayed, dr:Led tobacco extract, and one or more tobacco flavored mod:lEie:rs, such as levulinic ac:Ld, one or more flavoring materials, flnd one or more a~ro~ol Eorming substances, such as glycerin~ ~n especially useful alumina substrate is available from the Davison Chemical Division of W.R. Grace and Co. under the designation SMR-14-1896. Before use, this alumina is ..
sin-tered at elevated -temperatures, e.g. greater than lOOOaC, washed, and dried. In certa~n preferred embodiments, this alumina substrate can be mixed with densified tobacco particles, whlch particles may also be impregnated with an aerosol forming substance.
A significant improvement or advantage of the smoking article 10 over other similar smoking articles exists in the placement of th~ CO
oxidatiGn catalyst 22 between the combustible fuel element 20 and the aerosol-~enerating material 24. The CO oxidation catalyst 22 removes carbon monoxide produced by thc burning carbonaceous material in the : .
combus-tible fuel element 20. Such a removal results in a reduction i.n the amount of carbon monoxide inhaled by the user of the smoking articl~ .
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~ Non-limiting examples of suitable, eEfectlv~ CO oxidation ~ catalysts are: CuO-MnO2 catalysts such as, for example, catalysts sold under the trademark Hopcalite and available from Mine Safety Appliances;
alumina or magnesia-supported Pt and/or Pd ca-talyst ~preEerably also ; containing iron oxide, described in U.S. Patent 4,818,745, the disclosure of which is hereby incorporated of reference); compositions comprising a ceramic honeycomb support, tin dioxide Pt and/or Pd, and optionally other oopromoters (described in U.S. Patent 4,830,844, -the :-- , , 8 2~7~@~
disclosure vf which is hereby :Lncorporated of reference); titania or 7.i.rconia-supported plat:inum and iron oxide containing catalyst materials (optionally containing a ceramic honeycomb support which is coated wi-th titania or zirconia); hydrotalcite-supported platinum/iron oxide;
compositions comprising Pt and Fe-oxide on hydro-talcite; compositions comprising Pt and Fo-oxide on vanadium oxide; compositions which contain silvor motal or oxldo, manganeso oxldo, and an o~ide of cobal-t or iron;
and many of the commercially availabla catalyst compositions used for purifying exhaust gasos :Erom combllstion angines~ and usod .in C02 lasers (for racomb:Lning C0 an~ 2 ) ' Th~ ~o oxidation catalyst matc:riflls uscd :Ln tho apparatus o:E
thls invanti.on can havo any su:Ltablo shnpo such as cylindrical, ~.
ri.ng-shaped, honeycomb-shaped and the like. The materi.als can bo of any suitable si~o, for instanca A particlo diflmoter of about 0.0~ ~nchas to about 0.1 inchas for bead-shaped particles. The surfaco area of these catalyst materials generally is in the range of from about 10 to about 300 m2/g, proferably about 150 to about 250 m2/g. The shapa, size, surface structure and area and other structural parameters of the catalyst particles can be selected by those having ordinary skill in the art so as to provide maximum conversion of C0 to C0~ and minimum ;~
resistance to the flow of the combus-tion gas ex.tting from the burning fual element.
Preferably, the C0 o~idation catalyst 22 and aerosol-generating material 24 are enclosed within a heat-conductive tubular metal containor 14. The heat-conductive material preferably omployod in con~tructing tha proferrad container is typ.ically a metallic tube, strip, or foil, such as aluminum, which can vary in thickness from -~
less than about 0.01 millimeters to about 0.1 millimeters, or more. The ~:
thickness and/or type of conducting material can be varle~ (e.g. other metals, or the matorial sold undex the trademark Grafoil and available from ~nion Carbide) to achiove virtually any dosired dogree of heat transfer.
The fuel element heat insulating fibers 26 employed in practicing the invantion are preferably formed into a porous resilient ~: :

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jacket from one or more layers of heat insU]flting material.
~dvantageously, this jacket ls at least abou-t 0.5 mm thick, preferably at least abol1t l mm thick, more preferably between about 1.5 to 2 mm thick. Generally, the jacket extends over more than about half~ if not all o the length o~ the fuel element 20.
The currently preferred heat insulflting fibers 26 are ceram1c fibers and glflss fibers. Two suitable glass fibexs are avallable from the Manning Paper Company of Troy, New York, under thH desigllations, Manniglas lOOO and Manniglns 1200. When posslble, glass fiber ma-ter-ia1s having a low softening polnt~ e.g., below about 650C, are preferred.
The preEerrecl glass fibers include mat.erinls produced by Owens-Corning of Toledo~ Ohio under the des:Lgnat:lons 6432 and 6537.
The CO oxidation catalyst 22 and aerosol-generating mater:ial 24S or at least a portion -thereof, are circumscribed by a jacket of -tobacco-containing material 30 through which gases and vapors may pass during smoklng oE the article. During smoking, hot vapors are swept through the tobacco to extract the volatile components erom the tobacco, without combustion or substantial pyrolysis. Thus, th user receives an aerosol which contains the tas-tes and flavors of natural tobacco without the numerous combustion products produced by a conven-tional cigarette. -The jacket of tobacco-containing material 30 employed around the aerosol generating materI~l 24 may contain any tobacco available to the skilled axtisan, such as Burley, Flue~Cuxed, Turkish, xeconstituted tobacco, extruded tobacco mixtures, tobacco-containing sheets, and the like.
Advantageously, a blend of tobacco can be used to contxibute a greater variety of flavors. The jacket of tobacco-containing material 30 can also include conventional tobacco additives, such as fillers, casings, reinforcing agents, humectants, and the like. Flavor agen-ts can likewise be added to the jacket of tobacco-containing matexial 30, as well as flavor modifying agents.
The porous filter element 38 can be formed of any suitable material which can satisfactorily filter pax-ticulate ox other forms of solids as well as liquids from combustion gases passing therethrough ::

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while, passing filter~-1 gases thro~1gh the second end portion 42 of the filter element 38. It is presently preferred -to construct the filter element 38 from polypropylene ~ibers in, for example, the form of non-woven fa~ric. Such filters can also include low eEficiency cellulose acetate filters and hollow or baEfled plastic Ll-ters~ such flS ~.those made of polypropylene. Such filters do not appreciably in-terfere with the aerosol delivery. Tha embod:Lment of the invention in Flgure utilizes a Eiltor comprised of -two components. The first component is disposed ad~acent the aerosol-generatLng material 24 and i9 compr,~sed of a tobacco paper fil-ter 32. The, second component ~s disposed ad,jacent the tobacco paper fllte,r 32 and is comprlsed of a porous filter element 38, preferably comprising polypropylene.
Th~ e,ntlre length of the article, or Any portlon thereof, may be overwrapped with one or more layers of a suitable wrapper 44 such as cigare-tte paper, tobacco leaf, or tobacco paper. Generally, the wrapper 44 at the lighting end of the fuel element 48 should not openly flame during burning of the fuel element 20. In addition, the wrapper 44 should have controllable smolder properties and should produce a gray9 cigarette-like or- cigar-like ash.
In addition to the componellts described in Figure 1, the embodiment of smoking article lOA illustrated in Figure 5 also contains ;~
a second portion of CO oxidation catalyst 50 disposed between the heat conducting tubular metal container 14 and the wrappe,r 44. The second portion of CO oxidation catalyst 50 circumscribes either a portion o~
the fuel element 20 or a portion of the heat conducting tubular metal container 14, or a portion of both. The second portion oE CO oxidation catalyst 50 is positioned between the heat insulatirlg fibers 26 that surround the fue], element 20, and the jacket of tobacco-containing material 30 that surrounds the heat-conductive tubular metal container 14. The purpose of the, second portion of CO oxidatlon catalyst 50 is to remove or substantially remove carbon monoxide from the vapor stream that passes around the heat-'conductive tubular metal con-tainer 14 through the jacket of tobacco-containing material 30 to the first end ' :~,' ~.

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portion ].6 of the tubular metal contalner 14 by induclng the oxldation of C0 to C02.
The embodiment of smok.ing article lOB illustra-ted in Figure 6 also includes, :Ln addition to the elemen-ts depicted in Figure 5, a slightly modlfiad aerosol product:ion assembly 12A which differs from -the aerosol production assembly 12 by addlt:ionally including an elongated heat-conductive member 52 that is in direct heat-conductive contact with both the fuel element 20 and at leas-t a portion of the aexosol-generating material ~4. The heat-conduct:Lve member 52 is generally comprised of A thin metallic wire. The wlre :Ls preeerably comprised of copper. The wire can be of any suitable l.eng-th and diameter for effectively transferring heat from the :Euel element 20 to at leflst a porton of -the aerosol-generating material 24. The wire preferably has a d.iameter of abo~lt 0.05 cm. The wixe :Ls preferably about 2.0 cm or less in leng-th. Nore preferably, the wire is about 1.0 cm in length. The heat-conductive member 52 is anchored in the center hole of the fu~l element 20 and extends axially through the center of the heat-conductive tubular metal container 140 The heat-conductive member 52 reaches completely through the C0 oxidation catalyst 22 and extends into the aerosol-generating material 24. .
The purpose of such a heat-conductive member 52 :Ls to promote more effective transfer of heat from the burning tip of the fuel element 20 to the aerosol-generating material 24. This is necessary because the CO oxida-tion catalyst 22 inside the heat-conductive tubular metal container 14 can act as a heat sink, delaying the warmup of the aerosol-generating material 24 which in turn delays the appearance or generation of aerosol. Additionally, the heat-conductive member 52 heats up the C0 oxidation catalyst 22 more quickly, resul-ting in better conversion of carbon monoxide to carbon dioxide during the initial puEfs ~ :
from the cigarette-like smoking article lOB.
Figure 7 mors clearly illustrates the configllration for the aerosol production assembly 12 comprising the heat-conductlve tubular ~etal container 14 having a partially closed perforate first end portion 16 and the open second end portion 18, the combustible fuel element 20 ' - :! - :

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fixedly ~c(~lred in the ~cond end portion l8, the qu~ntity of CO
oxidation catalyst 22 di.sposed within the metal contalner 14 adjacent the fuel element 20~ and the ~uantity o.~ aerosol-generating ma-terifll 24 disposed within tlle me-tal container l4 intermediate the first end portion 16 thereof and the CO oxidation catalyst 22. Tho metal Contfliner 14 is cylindr:ical.ly shaped with the open second end portion 18 adjacent to the :Euel element 20. Preferably, several s:lot-liko openin~s 54 are provided in the closed perforate :First end portion 16 of the metal container 14. ~ preferrcd conigura-tion for s~l~h slo-t-llke openings 54 is shown in Figure 8. The pllrpose o:f these slot-].ike openings 54 :Ls to all.ow the aerosol crea-ted to escap~ -Erom the metal contalner ].4.
Wh:Lle tha metal container 14 could be of flny sui.table length and m~ter.tal thickness, generally~ -the -thlckness of the metal container 14 ranges :Erom about 0.01 mm or less to flbout 0.1 mm or more, and ranges from flbout 10 mm or less to about 50 mm or more ln length. Preferably, the metal con-tainer 14 ranges in :length from flbout 20 mm to about 40 mm, more preferably from about 25 to about 35 mm~ Advantageously, the diameter of metal container 14 is about 8 mm or less, preferably between about 3 flnd 7 mm, and more preferably between about 4 to 6 mm.
Generally, the diameter of the hea-t-conductive metal container 14 and the fuel element 20 are ~uch thflt one end of the fuel element 20 will fit tightly within the open second end portion 18 of the metal container 14. Generally, the heat-conductive metal container 14 extends over no more than about one half the length of the fuel element 20.
Preferably, the heat-conductive metal container 14 overlaps or otherwise contacts no more than about the rear 5 mm of the fuel element. This ContflCt is sufficient to hold the fuel element 14 in place while no-t substantially interfering with the burning of the fuel element 14.
In Figure 9 and Figure 10, a slightly modified version of the heflt-conductive metal container 14 is shown as is desigrlated by the :~
reference charac-ter 14A. This embodiment contains a plurality of circumferentially spaced pin-like holes 15 formed in the metal container 14A along a clrcumferential line near the juncture of -the combustible ' ~ ~ 7 93~7 f~lel element 20 ~nd the Co oxida-tlon cfltalyst 22 to be disposed there.in.
The purpose of the hvles 15 is to increase the amoun-t of oxygen available to the C0 oxi.dation catalyst 22. A higher oxygen co~centration will increas~, the carbon monoxide conv~rsion to carbon dio~ide that can be obtai.n~d.
Generally the pin-like holes 15 are of such si~,e and number so as to allow a sufficient amount oE oxygen to reach the catalyst in orcler to provide a maximum conversion of carbon monox:Lde to car'bon dioxlde.
While the pin-like holes 15 can be o:E any suitable number, generally -there are about 8 pln-like holes 15 formed in the metal container 14A.
Generally, the pin-like holes 15 are evenly spaced around the ci~cumference of the metal con-talner element 14~. Pr~ferably, the ' :
pin-like holes 15 are positioned so that they circumscr:Lbe the juncture between the uel element 20 and the C0 oxidation cata].yst 22 disposed within the metal container element 14A. Preierably, this posi-tion is about S mm from the open end of the me-tal container element 14A. While the pin-like holes 15 can be of any suitable sizeJ generally the pin~like holes 15 are less than abont 1 mm in diameter. Preferably, -the pin-like holes 15 are less than about 0.5 mm in diameter.
Figurs 11 illustrates an alternate configuration for the . '~
aerosol production assembly which is designated by the reference character ].2B. This aerosol production assembly 12B is characteri~ed by :~
physically separate container elements. The C0 oxida*ion catalyst 22 is contained within a heat-conduc-tive catalyst container eIement 56, while ~.
the aerosol-generating material 24 is contained within a heat conductive ~;
aerosol-generating material container element 58.
Generally, the catalyst container element 56 is cylindrically shaped with an open end adjacent to the fllel element 2Q and closed at the other periorated end. Generally, several slot-like openings 60 are provided in the perforate closed end of the catalyst container element 56 as shown in Figure 12. The purpose of these slot-like openings 60 is to allow the ilow of hot gases and vapors from the Euel element 20 'to the aerosol-generating material 24.
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Wh-Lle the catalyst contfllner elem~n-t 56 can be of any suitable I~ngth flnd material thickn~ss, generally, th~ thickness oE the catalyst container element 56 ranges from about 0.0l mm or less to about 0.1 mm, or more, flnd is less than flbout 30 mm in length. Pr~ferably, th~
catalyst container element 56 ls about 20 mm or less, more preferably about 15 mm or less in length. Advantageously, the diflmeter of the catalyst contalner element 56 is about 8 mm or less, preferab]y, from about 3 mm to about 7 mm, and more preferably from about 4 mm to ahout 6 mm.
Generally, the diameters o the catalyst cont~ln~r ~l~m~nt 56 and the ~uel element 20 nre such that on~ encl oE th~ fl~ lement 20 ~lll flt tlghtly wlthin the open end oE the catalyst carltfllller element 56. Generally, the catalyst container e1~ment 56 e~tends over no more than about one half tha length oE the fuel element 20. Preferabl~, the catalyst container element 56 overlaps or contacts no more than about the rear 5 mm of the fuel element 20. Thls will allow the catalyst container element 56 to hold the fuel element 20 securely while not interfering substantially with the burning of -the Euel element 20.
Generally, the aerosol-generating material container element 58 is cylindrically shaped with an opened end adjacent to the closed perforate end of the catalyst container element 56 and closed at the other perforated end. Preferably, several slot-like openings 62 flre provided in the perforate closed end oE the aerosol-generating material container element 58 as shown in Figure 12. The purpose of these slot-like openings 62 is to allow -the aerosol created to escape from the asrosol-generating material container element 58.
While the aerosol-generating ma-terial container element 58 could be of any suitable length and material thickness, generally the thickness of the aerosol-generating material container elemeut 58 ranges from about 0.01 mm or less to about 0.1 mm~ or more, and the element ranges from about 10 mm to about 50 mm in length. Preferably, the aerosol-generating material container element 58 is abou-t 40 mm or less, more preferably about 30 mm or less in length. Advantageously, the diameter of the container element 58 is about 8 mm or less, preferably, .... - , ~

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from about 3 mm to about 7 mm, and more preferflbly Erom about 4 mm to about 6 mm. Generally~ the diameter of the aerosol-generating material container element 58 and the catalys-t container element 56 are such that the closed end of the catalyst contalner element 56 will fit tightly within the ope.n end of the aerosol-generating material container element 58. Generally! the aerosol-generating material cont~iner elemerlt 58 extends over a sufficient portion oE the catalyst container element 56 so that the catalyst container elemen-t 56 is securely held adjac~nt to the aerosol-generating material container element 58.
~ n Figure 14 and Fig~lre l5, a slightly modLELed verslon of heat-conducting catalyst container element 56 i8 shown and is designa-ted by the reEerance character 56A. This embodiment con-tains a plurallty oE
circumfarentially spaced pln-like holes 64 formed in the catalyst contalner elemen-t 5fiA along a clrcumferentlal line near the juncture of -the combustlble fuel element 20 and the CO oxidation catalyst 22 to be disposed thereln. The purpose of the holes 64 is to lncrease the nmount of oxygen available to the C0 oxidation catalyst 22. A hlgher oxygen concentration will lncrease the carbon monoxide conversion -to carbon dioxide that can ba obtained.
Gensrally, the pin-like holes 64 are of such si7e and number so as to allow a sufficient amount of oxygen to rench the catalyst in order to provide a maxlmum conversion of carbon monoxlde to carbon ~- dio~ide. While the pln-like holes 64 can be of any suitable number, generally there are about 8 pin-like holes 64 formed in the catalyst contalner element 56A. Generally, the pin-like holes 64 are evenly spaced around the circumference of the catalyst container element 56A.
Preferably, the pln-llke holes 64 are positloned so that they circumscribe -the juncture between the fuel element 20 and the CO
oxidation catalyst 22 disposed within the catalyst con-talner elem~nt 56A. Preferably, this position is about 5 mm from the open end of the catalyst container element 56A. While the pin-like holes 64 can be of any suitable size, generally the pin-like holes 64 are less than about 1 mm in diameter. Preferably, the pin-like holes 64 are less than about 0.5 mm in diameter.

. .

32710~A

The aerosol produced by the articles constructed in accordance with the present invention is chemicfllly simple, conslsting essentlally of air, water, oxides of carbon, the aerosol former, any desired flavors or other desired volatile materials, and -trace amounts of other materials.
The wet total particulate matter (WTPM) produced hy articles of this invention has no measurable mutagenic activity flS measured by the ~mes Test, :l.e., there is no signiEicant dose response r21at:Lonship between the WTPM produced by articles of the present :in~ention and the number of revertan-ts occurring ill standard -test mlcroorganlsms exposed to such products. Accordlllg to the proponents of the Ames Test, a significant dose dependant rasponse indica-tes -the presence of mutagenlc materials :Ln the pxodue-ts testecl. Sae Ames e-t al, Nu-tatlon Research, 31:347-364 (1975); Nagas et al, Muta-tion Research, 42:335 (1977).
A furthar benefit from the present lnvention is a relative lack of ash produced during use in comparison to ash from a conventional cigarette. As the carbon fuel element is burned, it i8 essentially converted to oxides of carbon, with relative]y lit-tle ash generation, and thus there is no need to dispose of ashes while using the article.
Anoth~r important benefit from the variou~ embodiments of the present invention is the decrease in carbon monoxide produced in comparison to that produced by other known cigarette-like smoking articles.
Preferred embodiments of this invention are capable of delivering at leas-t 0.6 milligrams of aerosol, measured as wet total particulate matter ~WTPN), in the first three puffs, wh~n smoked under FTC smoking conditions, which consist of a 35 cc puff volume of 2 seconds duration, separated by 58 seconds of smolder. More preferably, embodiments of the invention are capable of delivering 1.5 milligrams or more of aerosol in -the first three puffs. Most preferably, embodiments of the invention are capable of delivering 3.0 milligram~ or mbre of aarosol in the first three puffs when smoked under FTC smoking conditions. Moreover, preferred embodlments of the invention deliver an average of ~t le:~t abotlt 0.8 milligrams of WTPM pel p~if for at least ' ~.

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:

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:: : : :,-32710C~

about 6 puffs, preferably at le~st about 10 puffs under FTC smoking conditions. More preEerably, preferred emhod:iments deliver 20 to 30 milligrams, or more, of WTPM over at least 10 puffs, under FTC smoking conditions .
A presently preferred smoking artic]e of the present invention fllso delivers very low level~ of carbon monoxide, pr~f~rably less -than about 10 milligrams total C0 delivery over the lLfe of the smoktng article, morc preferably, less thfln about 5 mLlligrams totnl C0 deliv~ry (e.g., about 0.01-4.5 milligrams~, most preferably less than about 3 milligrflms total C0 dellvery (e.g., about 0.1-2 mtlligrams).
As used hereln, and only for the purposes oE thls appllcation, "flerosol" is defined to include vapors, gases, particles, and the like, both visible and lnvisibla, ancl especially -those components perceived by the user to be "smoke-like", genera-ted by ac-tion of -the heat from the burning fuel ~lement upon ~ubstances contained withln the aerosol-generating means, or elsewhere in the article. As so defined, the term "aerosol" also includes vola-tile flavoring agents and/or pharmacologically or physiologically act:ive agen-ts, irrespective of whether they produce a visible aerosol.
As used herein, the term "conductive hea-t exchange relationship" is defined as a physical arrangement of the aerosol-generating means and the fuel elemen-t whereby heat is transferred by conduc-tion from the burning fuel element to the aerosol-generating means substantially throughout the burning period of the fuel elemcnt. Conductive heat exchange relationships can be achieved by locating the aerosol-generating means in close proximity to the burning portion of the fuel element, and/or by utilizing a conductive member to transfer heat from the burning fuel to the aerosol-generating means. Preferably, both methods of providing conductive heat transfer are used.
Advantages of the cigarette-like smoking article of the present invention will be further illustrated with reference to the follo`wing examples which aid in the understanding of the present invention, but which are not to be construed as limi-tations thereof.

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32710C~
18 2~
Ex m~
In this ~xample the preparaticn and prop~rties of several CO
oxldation catalysts are describcd. These catalysts wer~ tested in th~
smoking article of this invention~ as ls described in subsequent examples.
A CuO-MnO2 catalyst was prepflred in R~D laboratories o~
Phillips Petroleum Company in Bartlesville, Oklahoma as follows: To 150 ml of water (havlng been hea-ted to 75C) were add~d 20.7 g o~ -MnSO4~H20 and 6.2 g of CuSO4-5 1120. Upon complete dlssolutlorl of the coppor and man~anese sulfates, alr was bubbled -through the solutlon at a fast rate. Th~n 40 ml of an aqueo~s 25 weight-% NaO}I solutlon was added wlth stirrlng to the solution of copper and manganese sulfates. A
coprecipitate oE copper oxides/hydroxides and manganese oxides/hydroxides was formed, whlch WflS Eiltered, washed with wa-tar, ai~
driad and then heated for 3 hours at 200C in an oven. A brown, dry solid was obtained, which :is labeled Lab CuO-MnO2 ca-talyst. Its con~position is shown in Table 1.
Several commercifll CuO-MnO2 catalysts were obtained from Callery Chemical Co. Thcse materials ara labeled "Callery A", Callery B", and "Callery C". These CuO-MnO2 contain approximately 60 weight-% MnO2 and abou-t 40% CuO (as per disclosure in J. Am. Chem. Soc.
43~ 1921, page 1982). The exact compositions of the above-described CuO-NnO, catalysts are shoin ln Tabl~ t.

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327:L0C~
19 ~7~
Table 1 Lab Callery A Callery B Callery C
CuO-MnOz Cl:lO~MnO2 CuO-MnO2 CUo-Mno2 ~' ElementCfltalyst Cataly~_ Catalys_ Catal~st Ag 64 ppm 70 ppm 88 ppm 88 ppm ~
Ba 14 ppm 12 ppm 14 ppm 27 ppm :
Ca 2440 ppm 200 ppm 3690 ppm 1440 ppm Co 42 ppm --- 23 ppm ---Cr 125 ppm 123 ppm 132 ppm 151 ppm C~l 11.4% 11.~% 15.~% 12.9%
Fe 741 ppm 576 ppm 893 ppm 825 ppm K 1.9% 2.3% 1.8% 2.7%
Mn 55.1% 50.4% 48.0% 48.9%
No 319 ppm 297 ppm 319 ppm 378 ppm Na 6040 ppm 3250 ppm 2770 ppm 5560 ppm Ni 430 ppm 538 ppm 115 ppm 118 ppm Ph 730 ppm 821 ppm 744 ppm 508 ppm Sr 10 ppm 11 ppm 36 ppm 18 ppm Ti ~52 ppm --- 13 ppm ---V h2 ppm 33 ppm 58 ppm 92 ppm ~:

(Note: "%" means weight percent; "ppm" meaDs parts by weight per million parts by weight of CuO-MnO2 catalyst) An Ag-Mn-Co oxide catalyst (1:3:8 atomic ratio) was prepflred in the following manner. A solution as prapared by dissolving 12.7.1 g Na2CO3 in 500 ml H2O. When fully dissolved, 12.6 g KMnO~, were then added to the solution and dissolved. This solution was stirred while a second solution was slowly added, comprised of 8.5 g AgNO3, 28.0 g 50%
Mn(NO3)~ solution, and 113.4 g Cu(NO3)2-6}l2O dissolved in 500 ml ~i2O.
The mixture was stirred, filtered, and washed in 1 liter of H2O
containing 30 g NH4NO3 in order to remove tha Na and R from the sample.
This mixture was then washed in a like manner an additional three times uslng distilled water. The sample was dried at 110C for 3 hours, and then calcined at 400C for 20 hours. The resulting material was ground and sieved to 8-10 mesh. This catalyst is labaled ~ -Co oxide catalyst.
A titania-supported catalyst with platinum me*al and iron oxide as promoters was prepared by impregnating titania (provided by Degussa Corporation, Teterboro, New Jersey) with an aqueous solution : - : .
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2~7~2~
2~
contalning both Pt(NI13)4(N()3)~ and Fe(NO3)2-9H20. Concentrations of Pt and Fe in the sol~ltion and the welght ratio of the solut~on to titania were chosen sllch as to obtflin B final catalyst loading of about 1 weight-% Pt and about 0.5 weight-~O Fe. The Pt/Fe-impregnated titania was dried at about 125C, calc:Lned in alr for s~veral hours at 350C, and heated in a stream oE hydrogen gas at about 200-300C for several hours. Tbis catalys-t is labeled 1% Pt 5% FeL~iO~.
Several other Pt/Fe/TiO2 catalysts were prepared s~lbstantially in accordance with the above-described procedure except that Pt and Fe loadings wero difEer~1lt. These promoter lofldings wLIl be ldentiEied when tests are described in the exflmples below.
Example II
This example illus-trates the carbon monoxide outpu-t fox the preferred smoking articles of the present invent:lon. These articles were subs-tantially -those illustrated in Figure 1. For the tests in this example, -the articles were prepared by modifying -the RJR Pramier smokeless cigarett0.
The Premier unmodified cigaret-te was comprised of a carbonaceous fuel element in direct contact with an aerosol-generating materlal. The aerosol-generating material was enclosed within a metal container having a length of approximately 30 mm and a diameter of approximately 5 mm. The carbonaceous fuel element was of approximately lO mm in length and 5 mm in diqmeter, with longitudinal channels or passageways running through the length of the element. The fuel element was inserted into the open end of the aerosol-generating material container.
The fuel element was circumscribed by a layer of heat-insulating glass fiber of approximately 1.5 mm in thickness. The aerosol-generating material container was circumscribed by a layer of tobacco of approximately 1.5 mm in thickness. The mouthpiece end of the aerosol-generating material container was adJacent to a filter consisting of a cigarette paper filter adjacent to a nonwoven polypropylene filter. The en-tire article was wrapped in cigarette :

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2L 2079~
paper, and it had tha overall si~e and appearance of a conventional cigarette.
The Premier cigarette WAS modified by removing a portion of the aerosol-generating material from its container and replacing it with a C0 oxidation catalyst at the fuel element end of the con-tainer. Thls modlfica-tion was accompl:lshed by cuttin~ through the outer paper and tobacco one lnch from the cigarette tip. The canister was then opened at the partially perforated end ]6. All tbe aerosol-generating mater:L~l was then removed Erom the canister. The desired amount of C0 oxidat:Lon catalyst was loaded lnto the canister 30 as to be in clirect contact with the fuel source. The remaining space in -the can:lster WflS refllled wlth the aerosol-generating mater:Lal, and the perforated end of the canister was then reclosed.
For testingJ -tygon~ polymer tubing was fltted directly onto the exposed end of the me-tal container. Smoke was drawn through the tublng, through a particulate filter and into the cylinder of a smoking machine. The particulate filter was utllized to remove H70, glycerine and particulates prior to the gas chromatograph sampling. The smoke was then exhaled from the cylinder into an HP 3890 gas chromatograph.
Finally the smoke passed through an Anarad AR 400 Series infrared C0 analy~er and then to vent.
According to FTC smoking conditions, a "standard puff"
consists of a 35 cc draw in 2 seconds, wi-th one minute res-t between puffs. Because the tygon~ tubing in this e~periment was fitted directly onto the exposed end of the metal con-tainer rather than to the mouth-end of the smoking article, no air was drawn around the outside of the con-tainer during the test. There was approximately 30~O bypass around the container in the unmodified Premier cigarette. For this reason, the 35 cc/2 sec. standard puff was ad~us-ted to 25 cc/2 sec. for the canister only experiments. The results are shown in Table 2. The values shown in Table 2, as well as the values shown in all subsequent tables, are the average values for three runs.
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rablc 2 Rlln Catalys-t CO/CO (1) Total m~C0(2) 1 No catalyst 0.96 14.4 2 1% Pt, .5% Fe/TiO2 (l.00 mg) 0.37 7.7 3 LAB CuMnO2 ( 100 mg) 0.01 2.8 4 CALLERY A CuMnO2 (100 mg) 0.14 5.4 CALI,ERY B CuMnO2 ( 100 mg) 0.01 2.3 6 CALLERY B CuMn02 (80 mg) 0.11 4.0 7 CAII,ERY B CuMnO~ (50 mg) 0.27 7.2 ~ CAI.I.ERY C CuMIl02 ( 100 mg) 0.06 4.2 Notes~ CO/CO2ll .tn th:Ls ancl subseqllent Tables meaJIs mo:lecular ratio oE CO to CO~ .in the flltercd smoke, taken on -the thi.rd puff.
(2) "Total mg CO" in this and subsequen-t Tables means the total amount (in milligrams) of CO produced during one entire test using one Premier cigarette until complete ~xhaustion o:f the fuel source.
The CO/CO2 ratio is used as a measure of the completeness o~
the combustion to CO2. Test results in Table 2 clearly demonstratc the CO reducing effect of the tested catalysts (Runs 2-8) when compared to -the unmodified Premier cigarette canister (Run 1). The CuO-MnO2 catalysts (Runs 3-8) werc generally more effective than the Pt/Fe/TiO2 catalyst (Run 2).
Example III
Th~ ~rticles utili~ed in this exampl~ were substantially those described in Figure 1. The articles were prepared and tested in the same manner as those in Example II. Additionally, however~ some of the articles were provided with eight pin-like holes in the outer surface of the container, as shown in Figure 14 and Figure 15. The holes were made with the sharp poin-t of a #1 insect pin. The purpose of the holes was to provide additional oxygen to the catalyst in the container for more complete combustion of the carbon monoxide to carbon dioxide. Table 3 shows the carbon monoxide outpu-t for the articles with holes in the container, as compared to articles without such holes.

23 ~ 7s~0C~

Table 3 Ru _ Test De_ri~ L~ rO al mg CO
9 No catalyst, no holes 2.1 0.96 14.4 1% Pt, 0.5% Fe/TiO2 (100 mg), 2.1 0.37 7.7 no holes 11 1% P-t, 0.5% Fe/Tl02 (100 mg)~ 2.8 0.03 2.5 8 holes 12 Lab CuO/MnO2 ~100 mg), no holes 2.3 O.OI 2.3 13 Lab CuO/MnO2 ~tOO mg), 8 hol~s 2.8 O.Ol 2.1 Th~ O/C ratio clearly shows the holes are effectlve for increasing the amount of oxygen availflble for combust~.on of the carbon ; fuel. The additional oxygen significantly increases -the CO removal by the nobel m~tal -type catalysts, such as the 1% Pt, 0.5% Fe/TiO~
catalyst. The additional oxygen only sligh*:ly effec-ts the CO removal by the CuO/MnO2 ca-talysts.
~ Example IV ;:~
`. Th~ articles used in this example were substantially identical : to those described in Figure 1. The articles were prepared and tested : in the same manner as those in Example III, with 8 holes in the metal container to provide additional oxygen for the reaction. The effects of using 100 mg of catalyst with different promoter levals were investigated in an effort to redtlce the cost of the catalyst while maintaining a high activity. ~a-ta with various Pt and Fe weight percentages on TiO2 support are given in Table 4. ~ .

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2 ~ 7 2l~

Table 4 Run ~O Pt % Fe_ Total 0/C Ratio Tot l mg_C0 14 ~lank no catalyst 2~7 13.4 `;
1.0 0.5 2.7 2.5 16 Group 1 0.5 O.Z5 2.8 4.7 17 0.3 0.15 2.8 9.5 18 0.5 ()~o 2.7 11.2 19 Group 2 0.5 0.25 2.8 4~7 0.5 0.5 3.0 6.6 21 0.5 1.0 2.8 9.7 22 0.3 0.0 2.5 12.1 23 Group 3 0.~ 0.15 2.8 9.5 2~ 0.3 1.5 2.9 12.
In the utillzation of the preferred smoking articles of -the present invention, carbon monoxide passes to the user by flow around the ou-tside of th~ metal container as well as flow through the me-tal container. Tes$ results in Group I of Table IV demonstrate that as the Pt level decreases, the C0 conversion decreases. Test results in Groups 2 and 3 demonstrate that the addition of a small amount of Fe (Runs 18, 19~ 22 and 23) results in a substantial increase in the C0 conversion over the same catalyst witho~t Fe (Run 14). Furthermore, these results show that too much Fe can have a detrimen-tal effect on the activity of a low level Pt ca-talyst (Runs 19-21, 23 and 24).
Example V
This example illustrates the additional benefit that i.s incurred when cataly$ is positioned outside the metal container as well as inside the metal container. Additionally, this example illustrates that the positioning of the catalyst inside the metal container in close proximity to the aerosol-generating material for a substantial period of time will not result in a reduction of the catalyst activity. The .
articles utili~.ed in this example were substantially those described in Figure 5. The articles were prepared by modifying the RJR Premier smokeless cigarette. The cigarette was modified by removing a , .
'' ' ':
:' ' ' . ' ' : --2s ~7~5 portlon of the a~rosol-generating material from its container and replacing :it with a C0 oxidfltion catalyst at the fue]. e].ement end of the Contfliner~ as described in Example TI. Additionally~ a portion of c~talyst was placed outside -the metal container so that it circumscribed A portion o:E the container near the fuel element, as sh~wn in Figure 5.
This was accomplished by removi.:ng a po-rt:lon of thc tobacco adJacent to the glass fiber jacket that surrounds the fuel element and replaclng i-t wlth catalyst so that the catalyst was positioned between the glass fiber jacket and the tohflcco Jacket of thc ci~flrette.
In order for this expcrimcnt to accoun-t for alr flow flroluld the outsi.de of the canis-ter as well as through the lnside, -the c:Lgarette was completety reassembledl and -tygon~ tubing was fi-tted to -the mouth .
end oE the cf.garette. Standard FTC smoking condi-tlons were employed, i.e. a 35 ml puff Oe 2 s~conds duration, once every mlmlte. The amount of catalyst inside and ou-tside the me-tal container was varied.
Additionally, the effect of aging on the newly prepared clgarettes was tested. The results are shown ln Table 5.
Tab1e 5 Run _ Test Description ~L~ CO/CO2 Total mg C0 25 no catalyst ~unmodified Premier) 3.2 0.92 13.0 Lab CuO-MnO2 catalyst 26 100 mg inside canister, none outside 4.3 0.10 5.3 27 100 mg lnside canis-ter, 50 mg outside 4.2 0.03 3.0 -~
28 80 mg lnside can.ister, 50 mg outside 3.2 0.06 5.8 Aging tes-ts for Lab CuO-MnO2 catalyst: 100 mg inside, 50 mg outside 29 aged for 24 hrs before test:;ng 3.6 0.02 3.4 30 aged for 48 hrs 4.6 0.02 3.1 31 aged for 120 hrs 3.4 0.02 3.6 32 aged for 48 hrs at 50C 4.5 0.02 2.7 ~. ~
Addi~ion of catalyst outside the metal container decreased the total carbon monoxide (Run 27). Test results on aging of the cigarettes .

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from Iable 5 show that aglng up to 120 hours had no detrimental effect on the cAtalyst per~ormance.
Rxample VI
The art:icles utLlized in this example wer~ substflntially those described in Figuxe 6. The articles were prepared by modifying the RJR
Premier smokeless c:Lgaret-te. The cigarctte was modified by removing a portion of the aerosol-generating material from its con-tainer and replacing it wlth a CO o~idation catalyst at the fuel el~mcnt end o~ the container, as described in E~ample II. Alsol ln a]l artLcles, 50 mg of 28-48 mesh Callery CuO-MnO2 B cal.alyst were placecl o~ltsLde the conta:lner, as descr:lbed ln ExAmplc V. Add:lt:lonally, a short plece of 0.020 inch d:lamster copper wlre was anchored in -the center hole oE the carbon fucl element e~tending axially through the cen-ter of thc container. The length of the wire reached completely -through the catalyst bed and extended into -the aerosol-generating material.
The cigarettes were completely reassembled and tygon~ tubing fitted to the mouth end of the cigarettes. Standard FTC smoking conditions were employed, i.e. a 35 ml puff of 2 seconds duration, once every minute. The amount of catalyst inside the container was varied from 25 to 100 mg. Control tes-ts without the copper wiro were run -Eor each trial for comparison.
The amount of aerosol emitted from the cigare-t-te was recorded by carefully watching the clear tygon~ tube attached -to the mouthpiece of the cigarette. A numerical value for the amount of aerosol was designated for each puff on a scale from 0.0 to 1.0 (in increments of 0.25), where 0.0 is for no aerosol~ 0.5 is for moderate aeroso], and 1.0 is for full aerosol. Of course, these numerical assignments for the amount of aerosol are subiective and imprecise. Never-theless, this gives a useful (though approximate) method of quantifying -the amount of aerosol. As beEore~ the total mg of C0 is determined for each cigarette using the IR C0 meter. The tabulated aerosol and total mg CO data for all trials are given in Table 6 and Table 7. PufE #1 designates the puff that is utilized to light the cigarette. Puffs #9 and #10 show no aerosol because the fuel source has completely burned.

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Table 6 No 100 mg 75 mg 50 mg 25 mg _t l~st Gatal~ Ca-tal~st Catalyst Catalyst To-tfll mg CO 12.15 2.62 2.79 4.80 7.72 Pu~ # _ Aero~ol 0 0.00 0.00 0.00 0.00 0.00 1 0.50 0.00 0.00 0.25 0.33 2 1.00 0.33 0.42 0.75 0.75 3 t.00 0.50 0.67 1.00 l.00 ~ 1.00 1.00 0.92 ].00 1.00 1.00 0.75 1.00 l.O0 1.00 6 1.00 0.58 0.83 1.00 1.00 7 0.50 0.50 0.67 0.75 0.66 8 0.00 0.16 0.33 0.16 0.00 9 0.00 0.00 O.00 0.00 0.00 0 . 00 0 . 0~ 0 . 00 0 . 00 0 . 00 ,, : .

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Table 7 .:
100 mg 75 mg 50 mg 25 mg 25 mg Cat~lyst Catalyst Cataly~-t Catalyst Catalyst No Catalyst 2.0 cm 2.0 cm 2.0 cm1.0 cm 2.0 cm No WlreWlre Wlre Wire Wire Wire Total Mg C0 12.15 2.28 2.l0 2.70 ~.86 5.39 PufE ~ Aerosol _ _ _ O 0.00 0.00 0.00 0.0~ 0.00 0.00 1 0.50 0.16 0.25 0.13 0.25 0.42 2 1.00 0.66 0.58 0.38 0.72 0.92 3 1.00 0.91 1.00 0.88 0.92 1.00 ~ 1.00 1.00 1.00 1.00 1.00 1.00 1.00 0~83 1.00 O.g6 1.00 1.00 6 1.00 0.~6 0.91 0.79 0.88 0.83 7 0.50 0.42 0.58 0.50 0.50 0.17 8 0.00 0.00 0.00 0.00 0.00 0.00 9 -Q 0.00 0.00 0.00 0.00 0.00 :~ 10 0 . 000 . 00 0 . 00 0 . 00 0 . 00 0 . 00 Test reslllts in Table 6 show the effect of varying the amo~mt of catalyst inside the container in the absence of a copper wire. This data illustrates that adding catalyst inside the con-tainer reduces the amount of aerosol produced, especially during the initial puffs. Test results in Table 7 show the, effect of varying the amo~mt of catalyst inside the container with the addition of the copper wire described above. Comparing the wire and no-wire data shows that the addition of the copper wire increased -the observed aerosol in all cases except the 50 mg case. Additionally~ comparison of the wire and no-wire dfl-ta shows that the addition of the copper wire increased the C0 conversion rate in all cases. The increased CO conversion is apparently due to the copper wire heating up the catalyst more quickly, resulting in better conversion of C0 during the inltial puffs than is observed in the abs~nc~ of the copper ~ire.

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E~ le VII
The ar-ticles utiLl~ed in this exampl~ were substantially those illustrated in Figure 5. The articles were prepared by modlfying the RJR Premier smokeless clgarette as described in Example V. The portion of the catalyst placed outside the metal container comprised 50 mg oE
the Ag-Mn-CO oxide catalyst described in Example I~ The portion of -the catalyst placed inside the metal contalner comprised 100 mg of the Ag-Mn-CO oxide catalyst described in Rxample I. Standard FTC smoking conditions were ~mployed, i.e. a 35 ml puff of 2 seconds duration, once overy minute. Also, utlmodiEied Prem:ler clgarettes were tested for comparlson. The results are shown in Table 8.
Table 8 Run Test Desc_ ~tion L ~L~ Total m~ CO
32 No ca-talys-t ~unmodifLed Premier) 3.2 0.92 13.0 Ag-Mn-Co Oxide Catalyst 33 100 mg inside container, 50 mg outside 400 0.3 6.1 The r~sults of Table 8 clearly indica-te that the addition of the Ag-Mn-CO oxide catalys-t signl-ficantly increases the CO conversion for the Premier cigarette.
Reasonable variations, modifications and adaptations for various usages and conditions can be made wîthin the scope of the disclosure and the appended claims, withou-t departing from the scope of this invention.

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Claims

THAT WHICH IS CLAIMED IS:

1. Apparatus for producing aerosol, which comprises:
a combustible fuel element;
a quantity of CO oxidation catalyst having a first end portion and an opposite second end portion and disposed with the first end portion thereof adjacent said fuel element wherein said CO oxidation catalyst is selected from the group consisting of a titania-supported platinum and iron oxide catalyst, a silver-manganese-cobalt oxide catalyst and combinations thereof;
aerosol-generating means including an aerosol forming substance and disposed adjacent the second end portion of said catalyst for forming an aerosol in response to the application of heat thereto;
and heat-conductive means innerconnecting said combustible fuel element and said aerosol-generating means for transferring heat from said combustible fuel element to said aerosol-generating means.

2. Apparatus in accordance with claim 1, wherein said CO
oxidation catalyst comprises titania-supported platinum and iron oxide.

3. Apparatus in accordance with claim 1, wherein said CO
oxidation catalyst comprises a silver-manganese-cobalt oxide.

4. A cigarette-type smoking article comprising:
a combustible hollow tube having a first end portion, an opposite second end portion and an intermediate portion;
filter means disposed within said hollow tube adjacent the second end portion thereof;

apparatus for producing aerosol disposed within said hollow tube intermediate the first end portion thereof and said filter means, said apparatus comprising a combustible fuel element;
a quantity of CO oxidation catalyst having a first end portion and an opposite second end portion and disposed with the first end portion thereof adjacent said fuel elements;
aerosol-generating means including an aerosol forming substance adjacent the second end portion of said catalyst for forming an aerosol in response to application of heat thereto;
heat-conducting means interconnecting said combustible fuel element and said aerosol-generating means for conducting heat from said combustible fuel element to said aerosol-generating means wherein said heat-conducting means comprises an elongated metallic member having a first end portion and an opposite second end portion with the first end portion thereof in heat-conductive contact with at least a portion of said combustible fuel element and with the second end portion thereof in heat-conductive contact with at least a portion of said aerosol-generating means and wherein said elongated member extends through said quantity of CO oxidation catalyst; and said combustible fuel element being disposed within the first end portion of said hollow tube and said aerosol-generating means being disposed within said hollow tube adjacent said filter means.

5. A smoking article in accordance with claim 4 wherein said hollow tube and said apparatus for producing aerosol defines an annular space therebetween and wherein said smoking article further comprises:

a quantity of tobacco disposed within said annular space adjacent said catalyst and said aerosol generating means; and a quantity of porous heat insulation material disposed within said annular space adjacent said combustible fuel element.

6. A smoking article in accordance with claim 4 wherein said CO oxidation catalyst comprises titania-supported platinum and iron oxide.

7. A smoking article in accordance with claim 4 wherein said CO oxidation catalyst comprises a silver-manganese-cobalt oxide.

8. A smoking article in accordance with claim 4 wherein said CO oxidation catalyst is selected from the group consisting of a titania-supported platinum and iron oxide catalyst, a silver-manganese-cobalt oxide catalyst and combinations thereof.

9. A smoking article in accordance with claim 4 wherein the fuel element comprises combustible carbon.

10. A smoking article in accordance with claim 4 wherein the aerosol forming substance comprises glycerin-impregnated alumina particles.

11. A cigarette-type smoking article comprising:
a combustible hollow tube having a first end portion, an opposite second end portion and an intermediate portion;
filter means disposed within said hollow tube adjacent the second end portion thereof;
apparatus for producing aerosol disposed within said hollow tube intermediate the first end portion thereof and said filter means, said apparatus comprising a combustible fuel element;

a quantity of CO oxidation catalyst having a first end portion and an opposite second end portion and disposed with the first end portion thereof adjacent said fuel elements;
aerosol-generating means including an aerosol forming substance adjacent the second end portion of said catalyst for forming an aerosol in response to application of heat thereto;
heat-conducting means interconnecting said combustible fuel element and said aerosol-generating means for conducting heat from said combustible fuel element to said aerosol-generating means;
a heat-conductive metal container which encloses at least a first portion of the CO oxidation catalyst and at least a portion of the aerosol-generating means wherein said heat-conductive container is provided with a plurality of pin-like holes through the surface of said heat-conductive container so as to circumscribe said CO oxidation catalyst enclosed within said heat-conductive metal container; and said combustible fuel element being disposed within the first end portion of said hollow tube and said aerosol-generating means being disposed within said hollow tube adjacent said filter means.

12. A smoking article in accordance with claim 11 wherein said hollow tube and said apparatus for producing aerosol defines an annular space therebetween and wherein said smoking article further comprises:
a quantity of tobacco disposed within said annular space adjacent said catalyst and said aerosol-generating means;
a quantity of porous heat insulation material disposed within said annular space adjacent said combustible fuel element; and a second portion of CO oxidation catalysts within said annular space between said quantity of tobacco and said quantity of porous heat insulation material so as to circumscribe at least a portion of said heat-conductive metal container.

13. A smoking article in accordance with claim 12 wherein said heat-conducting means comprises:
an elongated metallic member having a first end portion and an opposite second end portion with the first end portion thereof in heat-conductive contact with at least a portion of said combustible fuel element and with the second end portion thereof in heat-conductive contact with at least a portion of said aerosol-generating means.

14. A smoking article in accordance with claim 13 wherein said elongated member comprises a thin metallic wire.

15. A smoking article in accordance with claim 14 wherein said thin metallic wire has a diameter not greater than 0.020 inches.

16. A cigarette-type smoking article comprising:
a combustible hollow tube having a first end portion, an opposite second end portion and an intermediate portion;
filter means disposed within said hollow tube adjacent the second end portion thereof;
apparatus for producing aerosol disposed within said hollow tube intermediate the first end portion thereof and said filter means, said apparatus comprising a combustible fuel element;
a quantity of CO oxidation catalyst having a first end portion and an opposite second end portion and disposed with the first end portion thereof adjacent said fuel elements;

aerosol-generating means including an aerosol forming substance ad the. second end portion of said catalyst for forming an aerosol in response to application of heat thereto;
heat-conducting means interconnecting said combustible fuel element and said aerosol-generating means for conducting heat from said combustible fuel element to said aerosol-generating means;
a first heat-conductive metal container having a first end portion, an opposite second end portion and an intermediate portion wherein said CO oxidation catalyst is enclosed within said first heat-conductive metal container, and a second heat-conductive metal container having a first end portion adjacent to said second end portion of said first heat-conductive metal container, an opposite second end portion and an intermediate portion, wherein said aerosol-generating means is enclosed within said second-conductive metal container; and said combustible fuel element being disposed within the first end portion of said hollow tube and said second end portion of said second heat-conductive metal container being disposed within said hollow tube adjacent said filter means.

17. A smoking article in accordance with claim 16 wherein said first heat-conductive metal container is provided with a plurality of pin-like holes through the surface of such first heat-conductive metal container so as to circumscribe said CO oxidation catalyst enclosed within said first heat-conductive metal container.