US3705589A - Tobacco substitute smoking mixture - Google Patents

Abstract

Smoking mixture for cigarettes, cigars, pipes and the like comprising a solid black condensate of a compound of the formula R1 COCH2.CH2COR2 wherein R1 and R2, which may be the same or different, are H, alkyl, hydroxyalkyl or formyl. The condensate is mainly an aldol condensation product resulting from reaction between the carbonyl groups and the methylene groups of the monomer. The solid condensate is preferably prepared in sheet form by mixing the condensate with a binding agent. Suitable additives such as carbohydrate material, inert porous fillers, flavorants, glow producers and tobacco may be admixed with the condensate to produce the final smoking product. The preferred condensates are succinaldehyde, acetonyl acetone and compounds of the formula H.CO.CH2CO.CO.H,H.CO.CH2CH2CO.CH2OH and H.CO.CO.CH2CH2CO.CH 2OH. This invention relates to smoking mixtures for cigarettes, cigars, pipes and the like. Smoking mixtures normally consist mainly of, or contain, a high proportion of natural tobacco and the opinion is now widely held that the smoking of tobacco, especially in cigarette form, increases the incidence of lung cancer. This has been attributed to the presence in tobacco smoke of carcinogenic compounds such as 3,4-benzpyrene, cilia toxic substances, for example hydrogen cyanide, which initiate the action of the carcinogen, cocarcinogens, for example phenols, which accelerate the action of the carcinogen and solid matter (tar) which may contain other harmful constituents. It is an object of this invention to provide smoking mixtures wherein a smoke-producing material, which produces a smoke containing a lower content of cilia toxic materials, cocarcinogens and ''tar'' than tobacco smoke, is used in total or partial replacement of tobacco.

Description

[22] Filed:

United States Patent Morman [72] Inventor: James Forrester Morman, Troon,

Scotland I [73] Assignee: Imperial Chemical Limited, London, England April 22, 1970 21 Appl. No.: 31,014

Industries [30] Foreign Application Priority Data 1 May 1, 1969 Great Britain: ..22,270l69 52 Us. 01 ..131/17, 131/2 51 Int. Cl. ...A24b 15/00, A24d 01/18, A24b 13/00 [58 Field of Search ..131/2,1s, 17, 140-144 [56] References cited" UNITED STATES PATENTS 3,112,754 12/1963 Diaz; ..l3l/2 2,943,958 7/1960 Schaflander ..l3l/2 3,034,931 5/1962 Kiefer ..i3l/2 OTHER PUBLICATIONS Preparation and Reactions of Dialkoxytetrahydrofurans by Fakstorp, aleigh and Schniepp from the Journal O The American Chemical Society Vol. LXXLL [4 1 Dec. 12,1972

Jan-Y April 1950 pages 869-874. 7 Dangerous Properties of Industrial Materials by N. Irving Sax published by theReinhold Book Corporation, New York, Third Edition 1968 pages 380 and 381 cited. 7

Primary Examiner-Melvin D. Rein Attamey.-Cushman, Darby & Cushman [57 ABSTRACT The solid condensate is preferably prepared in sheet form by mixing the condensate with a binding agent. Suitable additives such as carbohydrate material, inert porous fillers, flavorants, glow producers and tobacco may be admixed with the condensate to produce the final smoking product. The preferred condensates are succinaldehyde, acetonyl acetone and compounds of the formula H-CO-CH COCOH,H-CO-CH CH CO-CH 0H and H-CO-COCH CH CO'CH 0H.

9 Claims, No Drawings TOBACCO SUBSTITUTE SMOKING MIXTURE This invention relates to smoking mixtures for cigarettes, cigars, pipes and the like.

Smoking mixtures normally consist mainly of, or contain, a high proportion of natural tobacco and the opinion is now widelyheld that the smoking of tobacco, especially in cigarette form, increases the incidence of lung cancer. Thishas been attributed to the presence in tobacco smoke of carcinogenic compounds such as 3,4-benzpyrene, cilia toxic substances, for example hydrogen cyanide, which initiate the action of the carcinogen, co-carcinogens, for example phenols, which accelerate the action of the carcinogen and solid matter (tar) which may contain other harmful constituents.

It is an object of this invention to provide smoking mixtures wherein a smoke-producing material, which produces a smoke containing a lower content of cilia toxic materials, co-carcinogens and tar than tobacco smoke, is used in total or partial replacement of tobac- The smoking mixtures of this invention comprise, as at least part of the smoke-producing material, a solid condensate produced by acid or base catalyzed condensation of a compound of the formula R COCH -CH COR (I) wherein R and R, which may be the same or different, each represents a hydrogen atom, or an alkyl, hydroxyalkyl or forrnyl group or a precursor of such compound (I). The condensate is mainly an aldol condensation product resulting from reaction between the carbonyl groups and the methylene groups of the monomer (l).

The condensates from succinaldeh'yde, acetonyl acetone and from compounds of the formula l-l-CO-CH -CH CO-CO-l-l, l-l-CO-CH -CH -CO-CH,-OH or u-cococm-cm-co-cruou are especially valuable.

Suitable precursors of Compounds 1 are compounds containing a furan ring structure, for example furan, 2,5-dimethylfuran, furfural, furfuryl alcohol and 5- hydroxymethylfurfural and pentoses and hexoses, for example glucose and sucrose, which, on heating in the presence of acids as described in The Furans by Dunlop and Peters, Chapter 8 and in Review of Pure and Applied Chemistry, 1961, 14, 1 61 (Noyes), produce compounds having a furan ring structure. When heated in the presence of acid catalyst the furan ring opens to form compound I as an intermediate. Thus, furan gives succinaldehyde, (H'COCH CH CO' 2,5-dimethylfuran gives acetonyl acetone (CH CO' Cl-lyCH, -CO-CH furfural and pentoses give the compound I-l-CO-CH2-CH -CO-CO-H; fufuryl alcohol gives the compound H-CO-CH -CH CO'CH -OH; S-hydroxymethyl furfural and hexoses give H-CO'CO-CH 'CH CO'CH OH. The compound I condenses in the acid reaction conditions to form the solid condensate used in the smoking mixtures.

The smoking mixtures of the invention produce less tar and harmful constituents on smoking than corresponding mixtures containing tobacco only as the smoke-producing material. It is believed that only some of the methylene groups are involved in the initial condensation reactions leading to formation of the conden- Sate product. During smoking further condensation occurs with liberation of water, rather than pyrolytic breakdown into smoke components. Formation of a cross-linked thermally stable solid or char is thus favored, which can then glow-burn in the cigarette to harmless gaseous products.

It will be understood that the smoking mixtures of the invention may, in addition to the condensate of compound I, comprise other materials which are normal constituents of smoking mixtures such as, for example, tobacco, carbohydrates or other smoke-producing organic material and, as desired, any of the other modifying agents commonly used in such mixtures. For example, the mixturesmay comprise glow-promoting catalysts, materials to improve ash coherence and color, nicotine, flavoran ts or medicaments.

As glow-promoting catalysts for ensuring fire-holding capacity, alkali metal compounds are preferred.

As material to improve the ash, salts of ammonia, alkali metals or alkaline earth metals can be used and of these, salts of magnesium, calcium or ammonium are preferred.

Numerous beneficial flavoring materials may be included in the mixture. These include tobacco extracts, organic esters, essential oils, menthol, tonka bean or vanillan.

Glycerol and glycols such as, for example, ethylene glycol and di-, triand tetra-ethylene glycol are convenient humectants.

Other materials, such as carbonates or porous inert fillers, may be included in the smoking mixture to facilitate combustion, imparting a more open texture to the mixture, thereby facilitating access of oxygen.

It is convenient for smoking mixtures to simulate tobacco and the solid condensate is, therefore, preferably prepared in sheet form and, when required as a cigarette or pipe filling, shredded into strips. The sheet may conveniently be prepared by mixing the condensate, in powdered form, with a solution of filmforming agent such as, for example, a solution of a water-soluble cellulose derivative, starch, pectin, gun or mucilage, formed as a film and dried. Water-soluble methyl cellulose or sodium carboxymethyl cellulose, preferably in grades such that a 2 percent aqueous solution has a viscosity of at least 1,500 centipoises at 25C, may advantageously be used as the film-forming agent.

The remaining constituents of the smoking mixture may be mixed with the solution of film-forming agent but, if desired, soluble additives may be incorporated by spraying a solution of the additive on the formed sheet.

For use in cigarettes or pipes, the shred mixture is preferably conditioned'in a humid atmosphere to a moisture content of 5 to 15 percent by weight.

The invention is further illustrated by the following Examples in which all parts and percentages are by weight.

Example 1 A condensate of succinaldehyde was prepared by adding 250 parts of sulphuric acid gradually to an emulsion of 200 parts of furan and 50 parts of water, shaking the mixture for 3 days and then isolating the black solid condensation product which had been precipitated. The condensate was ground in a mortar and washed with water until the washings were free from acid and finely ground in a ball mill until it passed a BS. mesh sieve.

2 parts of sodium carboxymethyl cellulose were dissolved in 75 parts of water and 2.8 parts of glycerol, 1.0 part of potassium citrate, 0.8 part citric acid and 0.8 part ammonium sulphate were dissolved in 25 parts of water. The two aqueous solutions were united and stirred vigorously while 10.6 parts of the black powder condensate and 2 parts of calcium carbonate were added. The resulting slurry was stirred for 1 hour. The slurry was cast on glass plates and dried to a moisture content of 14 percent to give a film 0.5 millimeter thick. The film was cut into strips, shredded and made into cigarettes. The cigarettes gave a mild, acceptable smoke.

Example 2 A condensate of the compound l-l-CO-CH 'Cl-l -CO- COH was prepared by adding 20 parts of sulphuric acid to an emulsion of 100 parts of furfural and 20 parts of water, refluxing the mixture for 5 minutes and then isolating the black solid condensation product which had precipitated. The condensate was ground, washed with water till the washings were free from acid, dried and ground in a ball mill until it passed a BS. 120 sieve.

Cigarettes were made from this solid condensate as described in Example 1 except that 8.6 parts of the condensate and 2 parts of calcium citrate were used instead of 10.6 parts of condensate.

The cigarettes gave a mild and acceptable smoke. The smoke was analyzed for tar, hydrogen cyanide, phenols and 3,4-benzpyrene content.

The tar content was determined by drawing the smoke through a trap and weighing the condensate.

The hydrogen cyanide was determined by reacting the hydrogen cyanide in a methanol extract of the smoke with chloramine T and pyridine and reacting the glutaconic aldehyde formed with diethyl acetone dicarboxylate to give a red/violet complex which was estimated spectrophotometrically.

The phenols content was determined by steam distilling the phenols from a methanol extract of the smoke and reacting them with a stabilized diazonium salt of p-nitroaniline to give a colored product which was estimated spectrophotometrically. I

The 3,4-benzpyrene content was determined by isolating the 3,4-benzpyrene from a methanol extract of the smoke by means of a thin layer chromatograph (using a thin layer of cellulose acetate) and estimating it by its fluorescence spectrum.

The results, together with corresponding results for the smoke from a typical British flue-cured tobacco cigarette, were:

Smoke from Smoke from cigarettes cigarettes of this having blend Example of British tobacco Smoke condensate (tar) 3.8-7.5 26.3-27.8 mgJcigarene Hydrogen cyanide 20-28 pgjcigarette 172-251 Phenols pig/cigarette 13.5-17 214-306 3,4-benzpyrene g.lcigarette 35 X 35-43 X 10" The tar, hydrogen cyanide and phenols content of the smoke from the cigarettes of the Example were much lower than those of the smoke of British fluecured tobacco and the 3,4-benzpyrene content was about the same as that of the tobacco smoke. Thus, the smoke from the cigarettes of this Example would be less harmful than the smoke from flue-cured tobacco.

Example 3 A condensate of the compound H'CO-Cl-l, CHzCOCH OH was prepared b addirg 1 8 4 parts 9f sulphuric acid dropwise to a solution of 100 parts furfuryl alcohol in 200 parts of water at room temperature, stirring the mixture for five days and isolating the black-brown solid condensation product which had been precipitated. The condensate was ground, washed and incorporated in cigarettes as described in Example 1. The cigarettes gave a mild and acceptable smoke.

Example 4 A condensate of the compound l-lCO-COCH -Cl-l CO-CH Ol-l was prepared by adding 184 parts of sulphuric acid dropwise to a solution of 100 parts of 5- hydroxymethylfurfural in 200 parts of water at room temperature, stirring the mixture for 4 days and isolating the brown solid condensation product which had been precipitated. The condensate was ground and washed and incorporated in cigarettes as described in Example 1. The cigarettes gave a mild and acceptable smoke.

Example 5 Smoke condensate (tar) mgJcigarette 8.5-8.8 Hydrogen cyanide pg/cigarette 19-34 Phenols pig/cigarette 27-35 3,4-benzpyrene gJcigarette 35 X l0" The tar, hydrogen cyanide and phenols content of the smoke from the cigarettes of this Example were much lower than those of the smoke of British fluecured tobacco smoke and the 3,4-benzpyrene content is about the same as that of the tobacco smoke. Thus, the smoke from the cigarettes of this Example would be less harmful than the smoke from flue-cured tobacco.

Example 6 A condensate of the compound HCO-CO'CH -CH CO'CH Ol-l was prepared by adding 92 parts of sulphuric acid at room temperature to a saturated aqueous solution of glucose containing 276 parts glucose, maintaining the temperature at -90C for 30 minutes, after the initial rise in temperature due to hydration of H 80 and isolating the spongy black condensate produced. The condensate was ground, washed and incorporated into cigarettes as described in Example 1. The cigarettes gave a mild and acceptable smoke.

Example 7 A condensate of succinaldehyde was prepared by adding 4 parts of sulphuric acid slowly with stirring to a mixture of 18.8 parts of succinaldehyde (prepared as described in J. Amer. Chem. Soc. 72, 869) and 3 parts of water, stirring the mixture for 3 days and isolating the black solid condensate which had been precipitated. The condensate was ground, washed and incorporated into cigarettes as described in Example 1. The cigarettes gave a mild and acceptable smoke.

Example 8 To parts of acetonyl acetone were added 1.84 parts of concentrated sulphuric acid and the mixture was refluxed. After some time black oil and solid separated. The heating was maintained as for the initial reflux conditions for 20 hours, at the end of which the mixture was essentially solid. After cooling the black solid material was filtered and washed thoroughly with water until the washings were free from acid. 6.4 parts of solid were isolated. The solid was ground and made into cigarettes as in the previous Examples.

Example 9 To 10 parts of acetonyl acetone was added 0.5 part sodium hydroxide and the mixture was refluxed. After some time brown oil and'solids separated. The heating was maintained as for the initial reflux conditions for 20 hours, at the end of which time the mixture was essentially solid. After cooling the brown solid material was'filtered and washed with water until the washings were free from base. 7.5. parts of solid were isolated. The solid was ground and made into cigarettes as in the previous Examples.

What we claim is:

1. A smoking mixture in sheet form comprising a smoke-producing material and a film-forming agent therefor, the smoke-producing material being a black solid condensate produced by self condensation of a compound of the formula wherein R and R which may be the same or different, each represents a hydrogen atom or an alkyl, hydroxyalkyl or formyl group, the said self condensation being carried out in the presence of an acid or base catalyst at a temperature from ambient up to the boiling point for a time sufficient to produce the black solid.

2. A smoking mixture as claimed in claim 1 wherein the compound is selected from the group consisting of succinaldehyde, acetonyl acetone and compounds of the formula H-CO'CH -CHyCOCO-H, H'CO'CH; -CH -COCH -OH and H-CO'CO-CH -CH -CO-CH OH.

3. A smoking mixture as claimed in claim 1 including a carbonate or porous inert filler to facilitate combustion.

4. A smoking mixture as claimed in claim 1 comprising tobacco, carbohydrates or other smoke-producing organic material in addition to the smoke producing black solid condensate.

5. A smoking mixture as claimed in claim 1 including a glow-promoting catalyst, nicotine, flavorant, medicament, humectant or ash or color improver.

6. A smoking mixture as claimed in claim 1 wherein the compound I) is produced in situ is heating a precursor thereo consisting of a compoun which con- RCOCH 'CH CQR 1 wherein R and R which may be the same or different, each represents a hydrogen atom or an alkyl, hydroxyalkyl or formyl group, the said self condensation being carried out in the presence of an acid or base catalyst at a temperature from ambient up to the boiling point for a time sufficient to produce the black solid.

Claims (8)

1. 2. A smoking mixture as claimed in claim 1 wherein the compound is selected from the group consisting of succinaldehyde, acetonyl acetone and compounds of the formula H.CO.CH2.CH2.CO.CO.H, H.CO.CH2.CH2.CO.CH2.OH and H.CO.CO.CH2.CH2.CO.CH2OH.
2. 3. A smoking mixture as claimed in claim 1 including a carbonate or porous inert filler to facilitate combustion.
3. 4. A smoking mixture as claimed in claim 1 comprising tobacco, carbohydrates or other smoke-producing organic material in addition to the smoke producing black solid condensate.
4. 5. A smoking mixture as claimed in claim 1 including a glow-promoting catalyst, nicotine, flavorant, medicament, humectant or ash or color improver.
5. 6. A smoking mixture as claimed in claim 1 wherein the compound (I) is produced in situ by heating a precursor thereof consisting of a compound which contains a furan ring structure and produces said compound (I) upon heating in the presence of acid catalyst.
6. 7. A smoking mixture as claimed in claim 6 wherein the precursors of compound (I) are selected from furan, 2,5-dimethylfuran, furfural, furfuryl alcohol and 5-hydroxymethyl-furfural and pentoses and hexoses.
7. 8. A smoking mixture as claimed in claim 7 wherein the precursor of compound (I) is glucose or sucrose.
8. 9. A smoking mixture comprising tobacco and the black solid condensate produced by self condensation of a compound of the formula R1COCH2.CH2COR2 (I) wherein R1 and R2 which may be the same or different, each represents a hydrogen atom or an alkyl, hydroxyalkyl or formyl group, the said self condensation being carried out in the presence of an acid or base catalyst at a temperature from ambient up to the boiling point for a time sufficient to produce the black solid.