IL34410A - Smoking mixture - Google Patents

Description

SMOKING MIXTURE ji©»∑? nanpn 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, especiall in cigarette form, increases the incidence of lung cancer. THLs has been attributed to the presence in tobacco smoke of carcinogenic compounds such as 3, -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 tobacco.

The smoking mixtures of this invention comprise, as at least part of the smoke-producing material, a solid condensate produced by acid or base catalysed condensation 1 2 of a compound of the formula R COCH^ · CiL,COR (I) wherein 1 2 R and R , which may be the same or different, each represents a hydrogen atom, or an alkyl, hydroxyalkyl or formyl group or a precursor of such compound (I). The cQndensate is mainly an aldol condensation product resulting from reaction between the carbonyl groups and the methylene groups of the monomer (I).

The condensates from succinaldehyde, acetonyl acetone and from compounds of the formula H.CO.CHg. CHg. CO.CO.H, or H.C0.C0.CH2.CH2.C0.CH20H are especially valuable.

Suitable precursors of Compounds I are compounds containing a furan ring structure, for example furan, 2,5-dimethylfuran, furfural, furfuryl alcohol and 5-hydroxy-methylfurfural and pentoses and hexoses, for example glucose and sucrose, which, on heating in the presence of acids as described in 'The Purans ' by Dunlop and Peters, Chapter 8 and in 'Review of Pure and Applied Chemistry', 1961, 1_1±., 161 (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. CO. CH2. CH2. CO.H ) ; 2,5-dimethylfuran gives acetonyl acetone ( CH^ · CO. CIL, . CH,-,. CO. CH^ ) ; furfural and pentoses give the compound H. CO . CH2. CH2. CO. CO.H; furfuryl alcohol gives the compound H. CO. CH2. CH2. CO. CH2- OH; 5-hydroxymethyl furfural and hexoses give H.C0.C0.CH2.CH2.C0.CH20H. 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 condensate 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 favoured, 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 ether smoke-producing organic material and, as desired, any of the other modifying agents commonly used in such mixtures. For example, the mixtures may comprise glow-promoting catalysts, materials to improve ash coherence and colour, nicotine, flavourants 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. k Numerous beneficial flavouring 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-, tri- and tetra-ethylene glycol are convenient humectant s .

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 film-forming agent such as, for example, a solution of a water-soluble cellulose derivative, starch, pectin, gum or mucilage, formed as a film and dried. Water-soluble methyl cellulose or sodium carboxymethyl cellulose, preferably in grades such that a 2.% aqueous solution has a viscosity of at least 1500 centipoises at 25°C, 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 λ % 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 B.S. 1 20 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 1 0. 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 to give a film 0.5 millimetre 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 H. CO. CEL, . CH^ . CO. COH was prepared by adding 20 parts of sulphuric acid to an emulsion of 100 partes 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 B'.S. 120 sieve.

Cigarettes were made from this solid condensate as described in Example 1 except that 8.£? 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 analysed for 'tar', hydrogen ■ cyanide, phenols and 3 -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 spectrophotometrlcally.

The phenols content was determined by steam distilling the phenols from a methanol extract of the smoke and reacting them wit a stabilised, diazonium salt of p-nitroaniline to- give a coloured product which. as estimated spectrophotometryally.

The 3 j Lr-benzpyrehe content was determined by isolating the 3> -'benzpy.rene 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 flue-cured tobacco :Srn,oke condensate , ( 'tar ' ) .. 3 . 8-7 . 5 ' 26.3-27 . 8 : mg ./cigarette .

: Hydrogen cyanide . 20-28 · : 1 72-251 ^g. /cigarette : Phenols ^g. /cigarette : ■ 1 3 .5-17 : 2 -306 : ,+-Benzpyrene g. /cigarette: 35 x 1 0* 9 ■ 35^3 x 0" 9 ■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 flue-cured tobacco and the , 3,ij.-benzpyrene content was about the same as that of the IS 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. CHgCHgCOCHgOH was prepared by adding 18I. parts of 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 A condensate of the compound H. CO. CO. CH2. CH2. CO. CHgOH was prepared by adding 18L). 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 I . 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 f? A condensate of the compound HCO. CO. CH2. CH2. CO. CHgOH was prepared by adding 92 parts of sulphuric acid at room temperature to a saturated aqueous solution of sucrose containing J.7 . 7 parts of sucrose, maintaining the temperature at 80-90°C for 1 5 minutes, after the initial temperature rise due to hydration of and isolating the spongy black solid condensate produced. The condensate was ground and washed and incorporated into cigarettes, as described in Example 1. The cigarettes gave a mild and .acceptable smoke. The smoke was analysed for 'tar', hydrogen cyanide, phenols and 3 ,i-benzpyrene content and the results obtained were:- Smoke condensate (!tar') mg . /cigarette 8. 5-8 . 8 Hydrogen cyanide g . /cigarette 9-3^4- Phenols g . /cigarette 27-35 _ Q 3,i).-benzpyrene g. /cigarette 3 x 1 0 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 flue-cured tobacco smoke and the 3 ,^-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 H.CO.CO.CH^CH^CO.CH^OH was prepared by adding 92 parts of sulphuric acid at room temperature to a saturated aqueous solution of glucose containing 27 parts sucrose, maintaining the temperature at 80-90°C for 30 minutes, after the initial rise in temperature due to hydration of EL,S0^, 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 ij. parts of sulphuric acid slowly with stirring- to a mixture of 8.8 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 10 parts of acetonyl acetone were added I.8I4. 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. 6.1; 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 materi 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.

Claims (1)

1. WHAT WE CLAIM IS:- 1. A smoking mixture comprising, as at least part of the smoke-producing material, a solid condensate produced by acid or base catalysed condensation of a compound of the formula R C0CH2. CH^COR (I) (or a precursor thereof), wherein R1 and R2 , which may be the same or different, each represents a hydrogen atom, or an alkyl, hydroxyalkyl or formyl group. •2. A smoking mixture as claimed in Claim 1 wherein the condensate is mainly an aldol condensation product resulting from reaction between the carbonyl groups and the methylene groups of the monomer (I). 3. A smoking mixture as claimed in Claim 1 or Claim 2 wherein said smoke-producing material comprises the condensate from succinaldehyde , acetonyl acetone or compounds of the formula H. CO. CH2. CH2. CO. CO.H, Ξ. CO . CH2. CH2. CO . CH2. OH or I).. A smoking mixture as claimed in Claim 1 wherein the precursors of compound (I) are compounds containing a furan ring structure. 5. A smoking mixture as claimed in Claim 1+ wherein said precursor is selected from furan, 2,5-dimethylfuran, furfural, furfury1 alcohol, -hydroxymethylfurfural and pentoses and hexoses which on heating in the presence of acid produce compounds having a furan ring structure. 6. A smoking mixture as claimed in any one of the preceding claims comprising tobacco, carbohydrates or other smoke-producing organic material in addition to said solid condensate. 7. A smoking mixture ' as claimed in any one of the preceding claims comprising glow-promoting catalysts, materials to improve ash coherence and colour, nicotine, flavourants or medicaments in admixture with the smoke-producing material . b. A smoking mixture as claimed in Claim 7 wherein the glow-promoting catalyst comprises an alkali metal compound. 9. A smoking mixture as claimed in Claim 7 wherein the material to improve ash coherence comprises salts of ammonia, alkali metals or alkaline earth metals. 10. A smoking mixture as claimed in Claim 9 comprising salts of magnesium, calcium or ammonia as ash improvers. 11. A smoking mixture as claimed in Claim 7 wherein the flavourant comprises tobacco extracts, organic esters, essential oils, menthol, tonka bean or vanillan. 12. A smoking mixture as claimed in any one of the preceding claims comprising a humectant. 13· A smoking mixture as claimed in Claim 12 wherein the humectant is glycerol, ethylene glycol, di- tri- or tetra-ethylene glycol. U.. A smoking mixture as claimed in any one of the preceding claims comprising carbonate or porous inert fillers to facilitate combustion. A smoking mixture as claimed in any one of the preceding claims comprising a film-forming agent. 1 . A smoking mixture as claimed in Claim 1 $ wherein the film-forming agent comprises a water-soluble cellulose derivative, starch, pectin, gum or mucilage. 1 7 · ' A smoking mixture as claimed in Claim 16 wherein the water-soluble cellulose derivative is methyl cellulose or sodium carboxymethyl cellulose. 1 8. A smoking mixture as claimed: inr any one of the preceding claims in shredded form. 1 9 · . A smoking mixture substantially as hereinbefore described with reference to '.the Examples. 20 . A method of manufacturing the smoking mixture of any one of Claims 1 to 1 9 substantially as hereinbefore describ S. HOROWITZ & CO. AGENTS FOR APPLICANTS 1 1 AHcP/H /15. ^ - 70