US3251366A - Tobacco - Google Patents

Description

United States Patent 7 This application is a continuation-impart of our copending application Serial No. 283,999, filed May 29, 1963.

This invention relates to a tobacco product and has for an object the provision of a composition and process for improving the flavor and aroma of tobacco and tobacco smoke.

It is well known in the tobacco art that the flavor and aroma of the tobacco product and the smoke from the tobacco are very important considerations insofar as the ultimate consumer is concerned. Considerable efforts are exerted by the manufacturers of tobacco products to provide a product that will be acceptable to the consumer,

particularly as regards to flavor and aroma characteristics.

It :has been the common practice in the tobacco industry to prepare blends of domestic and oriental tobaccos in order to provide smoking tobacco which has a pleasing flavor and aroma before and during smoking. However,

such a procedure-is costly and may at times become prohibitive in the event th-atcertain types of tobacco may be in short supply. Accordingly, it is a further object of this invention to provide a new class of additive materials which when applied to the tobacco products improve and enhance the flavor and aroma of these products and the smoke emitted therefrom thereby increasing or enhancing the pleasure and other values that may be derived by the consumer from the use of these products.

A further object of this invention is the provision of a process for enhancing or otherwise improving the flavor, aroma and other qualities of certain domestic, oriential, reconstituted or synthetic tobaccos which may be deficient in said flavor or aroma or other qualities.

An additional object of this invention is to provide a process of preparing a smoking tobacco. or product which when smoked has an enhanced flavor or aroma.

A still further object of this invention is the provision of smoking products, such as cigarettes, cigars or pipe tobacco, and a process for forming same whereby the flavor and aroma before and during smoking are improved or enhanced.

Further and additional objects will appear from the following description and the appended claims.

In accordance with one embodiment of this invention, a

tobacco product is provided to which has been added or which has been treated with a small amount of a compound selected from the group of compounds having the formulae wherein R R R and R are selected from the group consisting of hydrogen and alkyl groups and R is an alkyl group. Preferably the alkyl groups are lower alkyl rad- 3,251,366 Patented May 17, 1966 icals of from 1 to 6 carbon atoms. The compounds falling within the scope of the generic Formulae I and II are a,B-unsaturated-'y-lactones with up to 3 alkyl substituents. The compounds falling Within the scope of Formula HI are lactols of the lactones of Formula I and may be designated a,/3-unsaturated-y-alkyl- -hydroxy butenolides. Thus, R R R R and R can be methyl, ethyl, propyl, isopropyl, butyl, isobutyl, pentyl and hexyl. In one preferred embodiment of this invention R and' R are each methyl, R is pentyl, R is hydrogen and R is normal butyl. With these values three compounds generically indicated in Formulae I, II and III are, respectively, a,/3-dimethyl-'y-pentylidenebutenolide, u, 8-dimethyl-'y-pentylbutenolide, and a,5-dimethyl-y-pentyl- -hydroxybutenolide.

The following specific examples illustrate the preparation and characteristics of representative tobacco additives of the present invention. It will be appreciated, however, that this invention is not limited to the specific processes by which the compounds may be prepared. All temperatures are expressed in degrees centigrade.

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Example I In the following will be presented one specific example of a process for preparing a,B-dimethyl-y-pentyl-y-hydroxybutenolide, u,[3-dimethy1 'y pentylidenebutenolide and a,fi-dimethyl-v-p'entylbutenolide which are preferred compounds used as additives for tobacco products in accordance with this invention.

To a solution of 30 grams of dimethylmaleic anhydride in 150 milliliters of dry benzene and 500 milliliters of anhydrous ether, at 0, was added over a two hour period 350 milliliters of an ether solution of amyl magnesium bromide prepared, in a nitrogen atmosphere, from 40.-

grams of amyl bromide and 7 grams of magnesium. Fifteen minutes after completing the addition of the Grignard reagent, the Grignard complex was decomposed by addition of 200 milliliters of a cold aqueous 5 percent sulfuric acid solution. The two layers were separated and the aqueous phase was extracted with 200 milliliters of ether. The ether solutions were combined and extracted with 300 milliliters of aqueous 10 percent sodium carbonate to remove the unreact'ed dimethylmaleic anhydride.

The desired lactol (a43-dimethyl-'y-pentyl-y-hydroxybutenolide) remaining in the ether solution was then removed, presumably as the sodium salt, by extraction with 400 milliliters of aqueous 1 M sodium hydroxide solution. The sodium hydroxide solution was acidified, at ()10 C., with 4-N hydrochloric acid and was extracted with 45 0 milliliters of hexane to recover the lactol. After drying the hexane solution, 28 grams of lactol, 11 1.4730, boiling point 134 (0.2 mm.), was obtained by evaporation of the hexane and is suitable for use as an additive to tobacco products in accordance with this invention.

In order to recover the unreacted dimethylmaleic anhydride, the above mentioned sodium carbonate solution was acidified, at O-10 C., and was extracted'with 300 milliliters of chloroform. After drying the chloroform solution, grams of impure dimethylrnaleic anhydride was recovered by evaporation of the chloroform. Recrystallization of the recovered dimethylmaleic anhydride from a mixture of chloroform and hexane resulted in a recovery of 8 grams of pure anhydride.

The lactol was converted to ix,B-dimethyl-y-peneylidenebutenolide by dehydration in the following manner. A mixture of 13 grams of lactol, 6 grams of p-toluenesulfonic acid and 350 milliliters of benezene was refluxed wit-h azeotropic distillation of Water until no more water was evolved. After cooling to room temperature, the reaction mixture was extracted with 200 milliliters of water, milliliters of 10 percent potassium carbonate to completely remove the p-toluenesnlfonic acid and 100 milliliters of water. After drying the benezene solution,

11.5 grams of the lactone, n 1.5103, boiling point 123 (0.5 mm.), was recovered by evaporation of the benzene.

This represents a 56 percent conversion of dimethylmaleic anhydride to the lactone or based on the amount of dimethylmaleic anhydride recovered a yield of 79 percent. This lactone is also suitable for use as an additive to tobacco products is accordance with this invention.

In order to prepare the additive a,/3-dimethyl-'y-penty1- butenolide, the following reagents, in the order listed, were added to 30 milliliters of ethyl acetate: 2 grams Darco K-B charcoal, 0.2 gram chloroplatinic acid dissolved in 2 milliliters of absolute ethanol, 5 grams of the lactone a,fi-dimethyl-ypentylidenebutenolide dissolved in 30 milliliters of ethyl acetate and 0.08 gram sodium borohydride dissolved in 5 milliliters of absolute ethanol. After two minutes 2.5 milliliters of glacial acetic acid was added. The reduction was carried out in a low pressure hydrogenation apparatus at room temperature and an initial hydrogen pressure of 28 pounds per square inch. Hydrogen uptake ceased after one hour. The reaction mixture, after removal of the catalyst by filtration, was extracted with 150 milliliters of l M potassium carbonate. The ethyl acetate solution was dried and the solvent was evaporated to yield 3 grams of a,fl-din1ethyl- 'y-pentylbutenolide, 11 1.4657, boiling point 87-89 (0.2 mm.). This represents a 60 percent yield based on the amount of the lactone of a,fi-dimethyl-' -pentylidenebutenolide used.

It has been found that these particular compounds when incorporated into tobacco products impart a flavor and aroma both before and during smoking reminiscent of celery seed which many smokers consider to be desirable in tobacco products. However, it is pointed out that the methods for defining or characterizing the quality of a flavor or aroma in the tobacco art are almost purely subjective and diflerent smokers may define the same flavor quite differently. Also, the compounds included within the broad scope of this invention where the alkyl substituents in the generic formulae are somewhat different than specified in the compounds named immediately above impart flavor and aroma to the tobacco products whichmay be difiicult to characterize on the basis of any recognized standard. Thus the compounds comprehended by this invention by subjective tests impart characteristic flavors which are desirable in tobacco products and the smoke therefrom even though the exact character thereof cannot be described on the basis of known standards.

Example lI.3,4-dimetlzyl-A" -butenolide The slow distillation of 16 grams of B-methyllevulinic acid gave a fraction (0.7 gram) which was resolved by vapor-phase chromatography into two peaks. The first and second peaks were identified by infrared and nuclear magnetic resonance data as being 3,4-dimethyl-A' -butenolide and 3,4-dimethyl-A -butenolide. The infrared and nuclear magnetic resonance spectra confirmed the identity of 3,4-dimethyl-A -butenolide having the formula Example III.3,4,4-trimetlzyl-A -butenolide (a) 3,4,4-trimethylbutyr0lact0ne.To a solution of 10 grams of fi-methyllevulinic acid in 80 milliliters of absolute ether was added 30 milliliters of methylmagnesium bromide (3 M in ether) over a period of one hour. After allowing the solution to stir for two hours, 50 milliliters of water was added while cooling, followed by 10 milliliters of acetic acid in 50 milliliters of water. The water layer was extracted with ether and the ether extracts were dried and distilled, yield 1.5 grams of 3,4,4- trimethyl-butyrolactone, boiling point 89-92/ 8 mm.

(b) 3,4,4-trimethyl-A' -butenolide.To a mixture of 1.5 grams of 3,4,4-trimethylbutyrolactone in 10 milliliters of concentrated hydrochloric acid at 0.5 C. was added dropwise 2.1 grams of bromine. The solution was then stirred an additional two hours and poured into a solu tion of ice water. The residue obtained from extracting the aqueous layer with ether was heated on an oil bath at 60 for one hour with milliliters of dimethylaniline. The solution was diluted with water, extracted with ether, and the ether layer was washed with 100 milliliters of 5 N hydrochloric acid and concentrated. Purification of the residue by vapor-phase chromatography gave 3,4,4-trimethyl-A""-butenolide having the structural formula Example I V.The synthesis of 3 -is0pr0pyl-A' -buterzolide (a) Z-isopropyl-1,3-propane di0l.Diethylisopropylmalonate (101 grams, 0.5 mole) was added dropwise to a solution of 30.4 grams of lithium aluminum hydride in 650 milliliters of anhydrous ether. After the addition was completed, the reaction mixture was refluxed for two hours and hydrolyzed by adding 150 milliliters of ethanol followed by 600 milliliters of 20% hydrochloric acid. Extraction of the acid layer several times with ether and concentration of the ether layer gave a residue that Was distilled at diminished pressure. Yield, 42.7 grams of 2-isopropyl-l,3-p=ropane diol, boiling point 118-120" C./ mm.

(b) 1 bromo 2 isopropylpropanoL-The foregoing glycol (42.7 grams) was saturated with anhydrous hydrogen bromide at 0 to 5 forfour hours, and the reaction mixture distilled yielding 26.8 grams of 1- brorno-2-isopropylpropanol, boiling point 102-106 C./ 7 mm.

(c) fi-isopropylbutyr0lact0ne.-To a solution of 12 grams of potassium cyanide in 75 milliliters of water was added 32.8 grams of 1-bromo-2-isopropylpropanol in 15 milliliters of ethanol. for 15 hours, cooled, diluted with milliters of water and acidified with 50% hydrochloric acid. Extraction with ether and distillation of the residue produced 12.5 grams of fi-isopropylbutyrolactone, boiling point 7376 C./1 mm.

(d) Bromination of B-isopropylbutyrolactone.A solution of p-isopropylbutyrolactone (1.2 grams) and N- brornosuccinimide (3.0 grams) in 20 milliliters of carbon tetrachloride was refluxed for two hours using an infrared heat lamp. The solution'was then cooled, filtered and concentrated under reduced pressure.

(e) Delzydrobromination of a-bromo-p-isopropylbw tyrolact0ne.-The residue from the bromination above was heated on an oil bath at 60 C. for one hour with 5 milliliters of dimethylaniline. The solution was diluted with milliliters of ether and washed five times with 10 milliliters of 6 N hydrochloric acid. Concentration of the ether layer gave a residue which was analyzed by vapor phase chromatography using a 6 foot silicon rubber SE- column. The starting material and product were obtained from the chromatogram and the infrared and nuclear magnetic resonance spectra of the latter compound confirmed its identity as 3-isopropyl-A -butenolide having the formula The solution was refluxed Example V.-The synthesis of 'y-ethyl-A -butenolide (a) Preparation of 4-ket0hexanoic acid.A mixture of one mole of methyl acrylate 86 grams), three moles of l-nitropropane (267 grams) and 0.5 mole of triethylarnine (50.5 grams) was kept at room temperature for seven days. Distillation of the reaction mixture gave 1 18.5 grams of methyl 4-nitrohexanate, boiling point 97-100 C./2 mm.

A solution of 120 grams of methyl 4-nitrohexanate in 720 milliliters of water containing 189 grams of sodium hydroxide was added to an ice-cooled, mechanically stirred solution of 212 milliliters of concentrated sulfuric acid in 660 milliliters of water at such a rate that the temperature of the reaction solution remained at 57 C.

Extraction with ether followed by distillation gave 49.6 grams of 4-ketohexanoic acid, boiling point 120-132 C./2 mm.

(b) Lactonization of 4-ketohexan0ic acid.-A one gram sample of 4-ketohexanoic acid was stirred with an excess of thionyl chloride (10 milliliters) for one hour. After removal of the thionyl chloride under reduced pressure, the residue was irradiated for 1.5 hours using a IOU-watt Hanovia mercury vapor lamp. Purification of the residue by vapor phase chromatography and nuclear magnetic resonance analysis gave 7-ethyl-A-"-butenolide having the formula C-C 2H Example VI The compound 2,3-dimethyl-Af"-butenolide is known to the art and can be prepared by known' procedures. It is a solid having a melting point of 42 C.

Infrared spectrum: 1732, 1680, 1122, 1025 and 757 cm.-

Nuclear magnetic resonance spectrum:-1-=5.32 (2), 7.95 (3), and 8.14 (3).

Analysis.--Calcd. for C H O :Mol. wt., 112. Found: Mass, 112. 7

As previously indicated, the various tobacco additives encompassed within the scope of this invention may impart to tobacco an aroma and flavor difficult to characterize. As. illustrative, the tobacco additive of Example VI imparts an aroma and flavor which some characterize as a sweet, brown sugar note.

In accordance with this invention, a compound embraced by generic Formulae I, II or III or mixtures thereof is added to tobacco or applied to a smoking article or its component parts in amounts of about 0.00005 to 0.5 percent by weight of the product. Preferably the amount of additive is between about 0.004 and 0.02 percent by weight in order to provide a tobacco product having a desired flavor and aroma. However, the amount used will depend upon the amount of flavor and aroma desired and the particular compound or mixture thereof that is used. The additive may be incorporated at any step in the treatment of the tobacco but is preferably added after aging, curing and shredding and before the tobacco is formed into cigarettes. Likewise, it will be apparent that only a portion of the tobacco need be treated and the thus treated tobacco may be blended with other tobaccos before the cigarettes or other smoking articles are formed. In such case the tobacco treated may have the additive in excess of the amounts above indicated so that when blended with other tobaccos the final product will have the percentage within the indicated range.

In accordance with one specific embodiment of this invention, an aged, flue-cured and shredded tobacco is sprayed with a 1% ethyl alcohol solution of a,/3-dimethyl- 'y-pentylidenebutenolide in an amount to provide a to bacco containing 0.002 percent by weight of the additive on a dry basis. Thereafter the alcohol is removed by evaporation and the tobacco is manufactured into cigarettes by the usual techniques. It has been found that the cigarette when prepared as indicated has a desired and pleasing flavor, an aroma which to some people is reminiscent of celery seed and is detectable and pleasing in the main and side smoke streams when the cigarette is smoked. A similar product is obtained when tobacco is similarly treated with 0:,[3-dimethyl-y-pentylbutenolide or afi-dimethyl-y-pentyl-'y-hydroxybutenolide.

The additives falling within the scope of this invention may be applied to the tobacco by spraying, dipping or otherwise, utilizing suitable suspensions or solutions of the additive. Thus water or volatile organic solvents, such as alcohol, ether, acetone, volatile hydrocarbons and the like, may be used as the carrying medium for the additive while it is being applied to the tobacco. Also, other flavorand aroma-producing additives, such as those disclosed in United States Patents Nos. 2,766,145, 2,905,575, 2,905,576, 2,978,365 and 3,041,2l1 may be incorporated into the tobacco with the additive of this invention.

While this invention is principally useful in the manufacture of cigarette tobacco, it is also suitable for use in connection with the manufacture of pipe tobacco, cigars or other tobacco products. Furthermore, the compounds may be added to certain tobacco substitutes of natural or synthetic origin and by the term tobacco as used throughout this specification is meant any composition intended for human consumption by smoking or otherwise, whether composed of tobacco plant parts or substitute materials or both.

Also, the invention has been particularly described with reference to the addition of the compounds directly to tobacco. However, it will be apparent that the compound may be applied to the paper of the cigarette or to the wrapper of acigar. Also it may be incorporated into the filter tip, the packaging material or the seam paste employed for gluing the cigarette paper. Thus a tobacco product is provided which includes the specified additives and tobacco although in every instance the compound need not be admixed with the tobacco as above specifically described.

While several particular embodiments of this invention are shown above, itwill be understood, of course, that the invention is not to be limited thereto, since many modifications may be made, and it is contemplated, therefore, by the appended claims, to cover any such modifications as fall within the true spirit and scope of this invention.

We claim:

1. A tobacco product having added thereto an amount suificient to alter the flavor or aroma .of the tobacco prodnot of a compound selected from the group of compounds having the formulae wherein R R R and R are selected from the group consisting of hydrogen and alkyl groups of l to 6 carbon atoms and R is an alkyl group of not more than 6 carbon atoms.

2. The product recited in claim 1 wherein the amount of said compound is between about 0.00005 and 0.5% by weight of the product.

3. The product recited in claim 1 wherein the amount of said compound is between about 0.0004 and 0.02% by weight of the product.

4. A tobacco product having added thereto and dispersed therein a small amount suflicient to improve the flavor thereof of u,,B-dimethyl-y-pentylidenebutenolide.

5. A tobacco product having added thereto and dispersed therein a small amount suflicient to improve the flavor thereof of a,,8-dimcthyl-y-pentylbutenolide.

6. A tobacco product having added thereto and dispersed therein a small amount suflicient to improve the flavor thereof of a,fi-dimethyl-y-pentyl-y-hydroxybutenolide.

7. The product recited in claim '4 wherein the amount of flavorant is between about 00004 and 0.02 percent by weight of said tobacco.

8. The product recited in claim wherein the amount of flavorant is between about 0.0004 and 0.02 percent by weight of said tobacco.

9. The product recited in claim 6 wherein the amount of flavorant is between about 0.0004 and 0.02 percent by weight of said tobacco.

10. A tobacco product having added thereto and dispersed therein a small amount suflicient to improve the flavor thereof of 3,4-dirnethyl-A -butenolide.

11. The product recited in claim 10 wherein the amount of flavorant is between about 0.0004 and 0.02 percent by weight of said tobacco.

12. A tobacco product having added thereto and dispersed therein a small amount sufi'icient to improve the flavor thereof of 3,4,4-trimethyl-A -butenolide.

13. The product recited in claim 12 wherein the amount of flavorant is between about 0.0004 and 0.02 percent by weight of said tobacco.

14. A tobacco product having added thereto and dispersed therein a small amount suflicient to improve the flavor thereof of 3-isopropyl-N- -butenolide.

15. The product recited in claim 14 wherein the amount of flavorant is between about 0.0004 and 0.02 percent by weight of said tobacco.

16. A tobacco product having added thereto and dispersed therein a small amount suflicient to improve the flavor thereof of v-ethyl-N -butenolide.

17. The product recited in claim 16 wherein the amount of flavorant is between about 0.0004 and 0.02 percent by weight of said tobacco.

18. A tobacco product having added thereto and dispersed therein a small amount suflicient to improve the flavor thereof of 2,3-dimethyl-A' -butenolide.

19. The product recited in claim 18 wherein the amount of flavorant is between about 0.0004 and 0.02 percent by weight of said tobacco.

20. A process for improving the flavor of a tobacco product which comprises adding thereto a small amount of a compound selected from the group consisting of compounds having the formulae wherein R R R and R are selected from the group consisting of hydrogen and alkyl groups of l to 6 carbon atoms and R is an alkyl group of not more than 6 carbon atoms.

21. A tobacco product having added thereto an amount suflicient to alter the flavor or aroma of the tobacco product of a compound selected from the group of compounds having the formulae wherein R R R and R are selected from the group consisting of hydrogen and alkyl groups and R is an alkyl group.

References Cited by the Examiner UNITED STATES PATENTS 2,766,147 10/1956 Rowland 13117 2,872,360 2/1959 Teague l3117

Claims (1)

1. A TOBACCO PRODUCT HAVING ADDED THERETO AN AMOUNT SUFFICIENT TO ALTER THE FLAVOR OR AROMA OF THE TOBACCO PRODUCT OF A COMPOUND SELECTED FROMTHE GROUP OF COMPOUNDS HAVING THE FORMULAE