# US 7,610,920 B2 · Thiol-functionalized sorbent for smoking articles and filters for the removal of heavy metals from mainstream smoke > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,610,920 B2 - Document ID: US7610920B2 - Status: Granted - Kind: B2 - Application number: 10/740,586 - Filed: 2003-12-22 - Published: 2005-06-23 - Granted: 2009-11-03 - Earliest claimed: 2003-12-22 - Assignees: Philip Morris USA Inc. - Inventors: Jay A Fournier; Zhaohua Luan - Web page: https://patentgrep.com/patent/US7610920B2 ## CPC - A24D 3/166: {Silicic acid or silicates} - A24B 15/42: by organic and inorganic substances {(A24B15/281 takes precedence)} - A24D 3/14: of organic materials as additive (of ion exchange materials A24D3/12) - A24D: CIGARS; CIGARETTES; TOBACCO SMOKE FILTERS; MOUTHPIECES OF CIGARS OR CIGARETTES; MANUFACTURE OF TOBACCO SMOKE FILTERS OR MOUTHPIECES - A24B: MANUFACTURE OR PREPARATION OF TOBACCO FOR SMOKING OR CHEWING; TOBACCO; SNUFF ## Abstract Smoking articles which use thiol-functionalized sorbents are provided. The thiol-functionalized sorbents comprise at least one thioalkylsilyl compound covalently bound to an inorganic molecular sieve substrate, where the thiol-functionalized sorbent is capable of removing at least one heavy metal constituent of mainstream smoke. The thiol-functionalized sorbents are particularly useful for the removal of mercury and/or cadmium from mainstream smoke. Methods for making cigarette filters and smoking articles using the thiol-functionalized sorbent, as well as methods for smoking a cigarette comprising the thiol-functionalized sorbent, are also provided. ## Claims ### Claim 1 A smoking article comprising a thiol-functionalized sorbent having at least one thioalkylsilyl compound covalently bound to an inorganic molecular sieve substrate, wherein the thiol-functionalized sorbent is located in a filter and is present in an amount effective for removing cadmium from mainstream smoke, and wherein the smoking article is selected from the group consisting of a cigarette, a pipe, a cigar and a non-traditional cigarette. ### Claim 2 (depends on 1) The smoking article of claim 1, wherein the smoking article is a cigarette. ### Claim 3 (depends on 1) The smoking article of claim 1, wherein the filter is selected from the group consisting of a mono filter, a dual filter, a triple filter, a cavity filter, a recessed filter, and a free-flow filter. ### Claim 4 (depends on 1) The smoking article of claim 1, wherein the inorganic molecular sieve substrate comprises mesoporous or microporous molecular sieves. ### Claim 5 (depends on 1) The smoking article of claim 1, wherein the inorganic molecular sieve substrate is selected from the group consisting of zeolite, aluminophosphate, mesoporous silicate, mesoporous aluminosilicate, and mixtures thereof. ### Claim 6 (depends on 5) The smoking article of claim 5, wherein the inorganic molecular sieve substrate comprises a zeolite. ### Claim 7 (depends on 6) The smoking article of claim 6, wherein the zeolite is selected from the group consisting of zeolite ZSM-5, zeolite A, zeolite X, zeolite Y, zeolite K-G, zeolite ZK-5, zeolite Beta, zeolite ZK-4, and mixtures thereof. ### Claim 8 (depends on 7) The smoking article of claim 7, wherein the zeolite is selected from the group consisting of zeolite ZSM-5, zeolite Y, and mixtures thereof. ### Claim 9 (depends on 1) The smoking article of claim 1, wherein the thiol-functionalized sorbent comprises 3-thiopropylsilane covalently bound to a zeolite. ### Claim 10 (depends on 1) The smoking article of claim 1, wherein the thiol-functionalized sorbent comprises a silicate material. ### Claim 11 (depends on 1) The smoking article of claim 1, wherein the thiol-functionalized sorbent comprises 3-thiopropylsilane covalently bound to a mesoporous silicate. ### Claim 12 (depends on 1) The smoking article of claim 1, wherein the thioalkylsilyl group is covalently bound on exterior and interior surfaces of the inorganic molecular sieve substrate and wherein the inorganic molecular sieve substrate is a mesoporous molecular sieve. ### Claim 13 (depends on 1) The smoking article of claim 1, wherein the thiol-functionalized sorbent comprises a thioalkylsilyl group having more than three carbons. ### Claim 14 (depends on 1) The smoking article of claim 1, wherein the thiol-functionalized sorbent is in granular form having a particle size from about 20 mesh to about 60 mesh. ### Claim 15 (depends on 1) The smoking article of claim 1, comprising from about 10 mg to about 300 mg of the thiol-functionalized sorbent. ### Claim 16 (depends on 1) The smoking article of claim 1, comprising from about 100 mg to about 200 mg of the thiol-functionalized sorbent. ### Claim 17 A cigarette filter comprising a thiol-functionalized sorbent having at least one thioalkylsilyl compound covalently bound to an inorganic molecular sieve substrate, and wherein the thiol-functionalized sorbent is present in an amount effective for removing cadmium from mainstream smoke. ### Claim 18 (depends on 17) The cigarette filter of claim 17, wherein the inorganic molecular sieve substrate comprises mesoporous or microporous molecular sieves. ### Claim 19 (depends on 17) The cigarette filter of claim 17, wherein the inorganic molecular sieve substrate is selected from the group consisting of zeolite, aluminophosphate, mesoporous silicate, mesoporous aluminosilicate, and mixtures thereof. ### Claim 20 (depends on 19) The cigarette filter of claim 19, wherein the inorganic molecular sieve substrate comprises a zeolite. ### Claim 21 (depends on 20) The cigarette filter of claim 20, wherein the zeolite is selected from the group consisting of zeolite ZSM-5, zeolite A, zeobte X, zeolite Y, zeolite K-G, zeolite ZK-5, zeolite Beta, zeolite ZK-4, and mixtures thereof. ### Claim 22 (depends on 21) The cigarette filter of claim 21, wherein the zeolite is selected from the group consisting of zeolite ZSM-5, zeolite Y, and mixtures thereof ### Claim 23 (depends on 17) The cigarette filter of claim 17, wherein the thiol-functionalized sorbent comprises 3-thiopropylsilane covalently bound to a zeolite. ### Claim 24 (depends on 17) The cigarette filter of claim 17, wherein the thiol-functionalized sorbent comprises a silicate material. ### Claim 25 (depends on 17) The cigarette filter of claim 17, wherein the thiol-functionalized sorbent comprises 3-thiopropylsilane covalently bound to a mesoporous silicate. ### Claim 26 (depends on 17) The cigarette filter of claim 17, wherein the thioalkylsilyl group is covalently bound on exterior and interior surfaces of the inorganic molecular sieve substrate and wherein the molecular sieve is a mesoporous molecular sieve. ### Claim 27 (depends on 17) The cigarette filter of claim 17, wherein the thiol-functionalized sorbent comprises a thioalkylsilyl group having more than three carbons. ### Claim 28 (depends on 17) The cigarette filter of claim 17, wherein the thiol-functionalized sorbent is in granular form having a particle size from about 20 mesh to about 60 mesh. ### Claim 29 (depends on 17) The cigarette Filter of claim 17, comprising from about 10 mg to about 300 mg of the thiol-functionalized sorbent. ### Claim 30 (depends on 17) The cigarette filter of claim 17, comprising from about 100 mg to about 200 mg of the thiol-functionalized sorbent. ### Claim 31 (depends on 17) The cigarette filter of claim 17, wherein the filter is selected from the group consisting of a mono filter, a dual filter, a triple filter, a cavity filter, a recessed filter, and a free-flow filter. ### Claim 32 (depends on 17) The cigarette filter of claim 17, wherein the filter comprises cellulose acetate tow, cellulose paper, mono cellulose, mono acetate, and combinations thereof. ### Claim 33 (depends on 17) The cigarette filter of claim 17, wherein the thiol-functionalized sorbent is incorporated into one or more cigarette filter parts selected from the group consisting of shaped paper insert, a plug, a space, cigarette filter paper, and a free-flow sleeve. ### Claim 34 (depends on 17) The cigarette filter of claim 17, wherein the thiol-functionalized sorbent is incorporated with cellulose acetate fibers forming a plug or a free-flow filter element. ### Claim 35 (depends on 17) The cigarette filter of claim 17, wherein the thiol-functionalized sorbent is incorporated with polypropylene fibers forming a plug or free-flow filter element. ### Claim 36 (depends on 17) The cigarette filter of claim 17, wherein the thiol-functionalized sorbent is incorporated in at least one of a mouthpiece filter plug, a first tubular filter element adjacent to the mouthpiece filter plug, and a second tubular filter element adjacent to the first tubular element. ### Claim 37 (depends on 17) The cigarette filter of claim 17, wherein the thiol-functionalized sorbent is incorporated in at least one part of a three-piece filter including a mouthpiece filter plug, a first filter plug adjacent to the mouthpiece filter plug, and a second filter plug adjacent to the first filter plug. ### Claim 38 (depends on 17) A method of making a cigarette filter, the method comprising: incorporating a thiol-functionalized sorbent into the cigarette filter of claim 17, wherein the thiol-functionalized sorbent comprises at least one thioalkylsilyl compound covalently bound to inorganic molecular sieve substrate. ### Claim 39 (depends on 38) The method of claim 38, wherein the filter is a mono filter, a dual filter, a triple filter, a cavity filter, a recessed filter, or a free-flow filter. ### Claim 40 (depends on 17) A method of making a cigarette, the method comprising: (i) providing a cut filler to a cigarette making machine to form a tobacco column; (ii) placing a paper wrapper around the tobacco column to form a tobacco rod; and (iii) attaching the cigarette filter of claim 17 to the tobacco rod using tipping paper to form the cigarette. ### Claim 41 (depends on 2) A method of smoking the cigarette of claim 2, comprising lighting the cigarette to form smoke and drawing the smoke through the cigarette, wherein during the smoking of the cigarette, the thiol-functionalized sorbent removes the at least one heavy metal constituent of mainstream smoke. ### Claim 42 A cut filler composition comprising tobacco and a thiol-functionalized sorbent having at least one thioalkylsilyl compound covalently bound to an inorganic molecular sieve substrate, wherein the thiol-functionalized sorbent is capable of removing at least some of a heavy metal constituent of mainstream smoke.