DE3884246T2 - Cigarette. - Google Patents

Description

The present invention relates to cigarettes and other smoking articles of this kind.

Cigarettes are popular smoking articles having a substantially cylindrical, rod-like structure having a quantity of tobacco (i.e., filler material cut into shape) enclosed in a wrapper such as paper, thereby forming a tobacco rod. Currently, popular cigarettes contain blends of tobacco material, with the majority of blends having a nicotine content of from about 1.2 percent to about 2.25 percent, more commonly from about 1.4 percent to about 2 percent, and most commonly from about 1.6 percent to about 1.8 percent, based on the dry weight of the tobacco material. It has been found desirable to manufacture cigarettes with cylindrical filters, with the end thereof and the end of the tobacco rod arranged in series. Typically, filters are made of fibrous material such as cellulose acetate and are attached to the tobacco rod using a restrictive tipping or tipping material.

Popular cigarettes classified as "full flavor" provide the smoker with a desirable tobacco aroma, taste and satisfaction. Typically, the "full flavor" cigarettes emit approximately 14 mg or more of FTC "tar" per cigarette. A second classification of popular cigarettes includes cigarettes classified as "full flavor low tar." Typically, the "full flavor low tar" cigarettes emit between approximately 8 to approximately 14 mg of FTC "tar" per cigarette and lower FTC nicotine levels compared to "full flavor" cigarettes.

A third classification of popular cigarettes includes the "ultra low tar" cigarettes. Such "ultra low tar" cigarettes emit even lower amounts of FTC "tar" and nicotine. Typically, the "ultra low tar" cigarettes emit less than about 7 mg of FTC "tar" per cigarette. The "full flavor low tar" and "ultra low tar" cigarettes traditionally have air diluents such as laser-cut perforations around their mouth end area or have high-efficiency filter elements to remove "tar" and nicotine from the mainstream aerosol.

In general, the taste or strength of cigarettes classified as having lower "tar" and nicotine levels is always perceived as weaker when compared to cigarettes whose characteristics approximate those of "full flavor" cigarettes. To enhance the taste, strength and satisfaction, it has been proposed to add numerous flavoring agents to the cut filler material of such lower "tar" cigarettes. However, such an addition generally results in a mainstream smoke which may be perceived as harsh or irritating to the consumer's mouth, nose and throat. In the 1972 study published by R.J. In the paper "Tobacco Flavoring for Smoking Products" published by the Reynolds Tobacco Company, it was proposed on pages 10 and 13 to treat tobacco, tobacco substitutes, filters and the like of a smoking product with a flavoring agent in the form of levulinic acid in order to give the smoke more body and a sweet caramel flavor.

In addition, the use of tobaccos with a naturally high nicotine content as cut filler material is possible to enhance the tobacco taste, strength and satisfaction obtained from such cigarettes. However, High nicotine content cigarettes (ie cigarettes containing tobacco blends with a natural nicotine content of more than about 2.25% by weight) generally tend to produce unpleasant tasting mainstream smoke which may be perceived as harsh or irritating to the consumer's mouth, nose and throat.

It is therefore an object of the invention to improve the smoking character of such cigarettes so that their smoke is not perceived as excessively harsh or irritating. In particular, it would be desirable to provide a cigarette such as an "ultra low tar" cigarette with the ability to deliver the good tobacco flavor, strength and satisfaction characteristic of a "full flavor low tar" cigarette and at the same time be perceived as pleasant tasting but not excessively harsh or irritating. It would also be desirable to provide a cigarette such as a "full flavor low tar" cigarette with the ability to deliver the good tobacco flavor, strength and satisfaction characteristic of a "full flavor" cigarette and at the same time be perceived as pleasant tasting but not excessively harsh or irritating. Furthermore, it would be desirable to improve the smoking character of cigarettes in which tobaccos or other tobacco materials with very different nicotine contents are used.

This object is achieved by the cigarette defined in claim 1.

The present invention relates to a smoking article which delivers a good tobacco taste and at the same time is capable of delivering relatively low amounts of FTC "tar". Preferred articles according to the invention are cigarettes which have the characteristic (s) of "full flavor low tar"cigarettes. flavor, strength and satisfaction. Also preferred are cigarettes that deliver the flavor, strength and satisfaction characteristic of full flavor low tar cigarettes and the relatively low FTC "tar" levels characteristic of ultra low tar cigarettes. In addition, the preferred cigarettes taste extremely pleasant and give the perception of a smooth smoking character (ie, do not give the perception of a harsh or irritating character) relative to a comparable cigarette with similar FTC "tar" levels.

Cigarettes with

(i) a relatively low ratio of FTC “tar” to FTC nicotine,

(ii) a relatively low ratio of FTC carbon monoxide to FTC nicotine,

(iii) good tobacco taste, strength and satisfaction, and

(iv) a smooth, pleasant smoke character without being overly mild in taste.

Generally, the levulinic acid is added to at least a portion of the smokable material. The acid may be present in the cigarette in dissociated and/or non-dissociated form. The levulinic acid may be present in the cigarette as levulinic acid and/or levulinate ion.

In this specification, the term "dry weight", with respect to the smokable material of the smoking article, means the mass of the smokable material after drying for three hours at 214º F (101º C) in a forced draft oven until a constant weight is achieved. See Moseley et al, Ind. Eng. Chem., Vol. 43, p. 2342 (1951).

As used in this specification, the term "nicotine content" means, in relation to the smokable material, the mass of the alkaloid nicotine as determined by spectroscopic method, divided by the dry weight of the smokable material analyzed. See Harvey et al, Tob. Sci., Vol. 25, p. 131 (1981).

The smokable material from which cigarettes according to the invention are conveniently made may be a cut filler material made from one or more tobacco materials having an inherently high nicotine content. The tobacco material(s) having an inherently high nicotine content may be used alone or as mixtures with

(i) one or more tobacco materials with low nicotine content, and/or

(ii) one or more tobacco substitutes. Cigarettes according to the invention as such include those cigarettes whose smokable material has a total nicotine content or a nicotine content of the mixture of more than approximately 2.25 percent.

A cigarette according to the invention may conveniently contain at least one salt obtained from nicotine and an organic acid. The salt is added to the cigarette as an additive. Preferably, the salt is such that the molar ratio of nicotine to organic acid is 1:3. Most preferably, the salt additive comprises nicotine levulinate. The salt in question is contained in the cigarette in such a way that during use of the cigarette the salt is subjected to decomposition conditions. For example, a cigarette according to the invention may contain a smokable material and at least one salt of nicotine and an organic acid as an additive, wherein

(i) the nicotine content of the cigarette is more than approximately 2.25 per cent based on the dry weight of the smokable material, and

(ii) one of the above salts is nicotine levulinate.

The presence of the salt obtained from nicotine and levulinic acid in the cigarette results in an improved tobacco taste, strength and smoking pleasure as well as improved or maintained taste characteristics of the aerosol during use of the article while avoiding undesirable bad aftertaste.

SHORT DESCRIPTION OF THE DRAWING

Figure 1 shows a longitudinal section of a cigarette according to the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

An embodiment of the invention is shown in Figure 1 and is in the form of a cigarette 10. The cigarette comprises a generally cylindrical rod 15 of smokable material 20, such as cut tobacco filler material, which is contained within a confining outer wrapper material 25. The rod 15 is hereinafter referred to as a "tobacco rod". The ends of the tobacco rod are open to expose the smokable material. The cigarette 10 also comprises a filter element 30 disposed adjacent one end of the tobacco rod 15 such that the filter element and the tobacco rod are axially end-to-end and preferably abut against one another. The filter element 30 is substantially cylindrical in shape and has a diameter substantially equal to the diameter of the tobacco rod. The ends of the filter element are open to allow the passage of air and smoke therethrough. The filter element 30 comprises filter material 35, which is covered along its longitudinal surface with externally encircling filter plug covering material 40.

The filter element 30 is secured to the tobacco rod 15 by means of a tipping material 45 which circumscribes both the entire length of the filter element and an adjacent portion of the tobacco rod. The inner surface of the tipping material 45 is firmly bonded to the outer surface of the filter plug wrapping material 40 and the outer surface of the wrapping material 25 of the tobacco rod using a suitable adhesive. Optionally, a ventilated cigarette or an air-diluted cigarette is provided with an air-diluting device, for example a series of perforations 50, each perforation extending through the tipping material and the filter plug wrapping material.

Typically, the tobacco rod has a length of about 50 mm to about 85 mm and a circumference of about 17 mm to about 27 mm, and its wrapping material is a conventional cigarette wrapping paper. Suitable cigarette wrapping papers are commercially available from Kimberley-Clark Corp. under reference numbers 719 and 856 or from Ecusta Corp. under experiment numbers TOD 01788 and TOD 03363. If desired, a double wrap may be used. The tobacco rods and the resulting cigarettes may be made in any known configuration using known cigarette manufacturing processes and equipment.

Typically, the filter element has a length of about 20 mm to about 35 mm and a circumference of about 17 mm to about 27 mm. The filter material may be any suitable material such as cellulose acetate, polypropylene, tobacco material or the like. Filter materials having compositions or properties with a low filtering effect with respect to nicotine may be used. The filter plug wrapping material is typically a conventional paper filter plug wrap material and may be either air permeable or substantially air impermeable. However, if desired, an unwrapped cellulose acetate filter element may be used. The various filter elements suitable for use in this invention may be manufactured using known methods and equipment for cigarette filter production.

Typically, the tipping wrapper material circumscribes the filter element and an adjacent portion of the tobacco rod in such a way that the tipping wrapper material extends approximately 3 mm to 6 mm along the tobacco rod. Typically, the tipping wrapper material is a conventional tipping paper material. The tipping wrapper material may have varying porosities. For example, the tipping wrapper material may be substantially air-impermeable or air-permeable, or may have an area of perforations, openings or air holes as a result of treatment (e.g., by mechanical or laser perforation processes) thereby providing a means of air dilution for the cigarette. The total surface area of the perforations and the arrangement of the perforations along the cigarette circumference may be varied to determine the functional characteristics of the cigarette.

In this specification, the term "air dilution" means the ratio (generally expressed as a percentage) of the volume of air drawn through the air diluent to the total volume of air and aerosol drawn through the cigarette and exiting the outermost mouthpiece region of the cigarette. For cigarettes with air dilution or ventilation, the level of air dilution may vary. Preferably, the level of air dilution in a cigarette is greater than about 20 percent, more preferably greater than about 30 percent. The upper limit of air dilution in a Cigarette smoking is usually less than about 80 percent, and more often less than about 60 percent.

The smokable material used in making the tobacco rod can vary. For example, the tobacco material can be made in a processed form such as an extrudate (e.g., as a rod-shaped foam extrudate or a tubular extrudate), in the form of a filler material such as cut tobacco filler material, or the like. In general, the tobacco material of cigarettes is in the form of cut filler material. In this specification, the terms "filler material" or "cut filler material" include tobacco materials having a shape suitable for use in making cigarette tobacco rods. Filler material as such can include tobacco materials which are blended and in a shape ready for making cigarettes. The tobacco filler materials are conveniently used as rods or shreds, as is common in conventional cigarette manufacturing. The cut tobacco filler material can be used, for example, in the form of strands cut to a thickness of from about 1/25 inch to about 1/60 inch, preferably from about 1/30 inch to about 1/40 inch. Generally, such strands have lengths of from about 0.25 inch to about 3 inches.

Tobacco materials may be subjected to casing and top dressing processes, which are conventionally carried out at various stages of cigarette manufacture. For example, additives such as flavorings and humectants may be added to the tobacco material, as is common in cigarette manufacture. Suitable additives include flavorings such as vanillin, cocoa, licorice, menthol, tobacco flavor oil, tobacco extracts, and the like. Such additives are conveniently added to the smokable material as top dressing ingredients.

The majority of the filler material contained in the smokable rod is a tobacco material. However, the tobacco material may be blended with another smokable material such as a tobacco substitute. Examples of suitable tobacco materials include flue-cured, burley, Maryland or oriental tobaccos; processed tobacco materials such as expanded tobaccos, processed tobacco stems, reconstituted tobacco materials or reconstituted tobacco materials with different endogenous and exogenous nicotine concentrations; or mixtures thereof. Optionally, the tobacco materials may be blended with small amounts of carbonized and/or pyrolyzed materials.

Tobacco material(s) having a naturally high nicotine content constitute(s) at least a portion of the smokable filler material useful in making the smoking articles of the present invention. Typically, such suitable high nicotine tobaccos or processed high nicotine tobaccos have a nicotine content of greater than about 2.5 percent. The nicotine content of high nicotine tobacco materials is often greater than about 3 percent, frequently greater than about 4 percent, and in certain circumstances even greater than about 5 percent. The nicotine content of tobacco materials useful in this invention generally does not exceed about 10 percent.

The high nicotine filler material can vary. For example, the types of tobacco designated by the USDA as Type 35 (One Sucker), Type 36 (Green River), and Type 37 (Virginia Sun Cured) are common high nicotine tobaccos. A cultivar such as Nicotiana rustica often has a natural nicotine content of about 6 percent to about 10 percent. In addition, the leaves from the top of the stem of commercial varieties of flue-cured tobacco (designated by the USDA as Types 11 - 14) are also and Burley tobacco (designated Type 31 by the USDA). The natural nicotine content of many tobaccos can depend on the agronomic conditions under which the tobacco varieties are grown, as well as the specific genetic line of the tobacco.

Processed tobacco materials may be used. Such processed tobaccos may be created by tobacco reconstitution processes. For example, materials may be made by extrusion, film casting, fourdrinier or papermaking processes. Raw materials used in the manufacture of processed tobaccos may include those high nicotine tobaccos described above; also, various types of tobacco extracts may be used in the processed tobacco manufacturing steps. On the other hand, processed tobaccos may also be manufactured under suitable conditions to create products with different nicotine contents. Optionally, nicotine may be added to the solvents used for expansion, which are used to create volume-expanded high nicotine tobacco material. A typical expansion process is described in U.S. Patent No. 3,524,451 (Fredrickson). Processed tobacco materials also include tobacco or tobacco materials mixed with tobacco extracts, spray-dried tobacco materials or tobacco flavouring oils or otherwise treated. Processed tobacco materials as such have a high nicotine content after completion of the processing steps required for their preparation or manufacture and before their use in the manufacture of cigarettes.

Tobacco(s) with high nicotine content and/or processed tobacco(s) with high nicotine content may be used as the tobacco material of the cigarette, as component(s) of cigarette blends or as parts of the components of cigarette blends For example, high nicotine tobacco(s) and/or processed tobacco material(s) may be blended with tobacco substitute(s) having a nicotine content of less than about 2 percent. Typically, so-called "American blends" having a high nicotine content (i.e., having a total nicotine content of the blend of more than about 2 percent) are desired for cigarette manufacture. The total nicotine content of the tobacco material or blends of materials from which the tobacco rods for the cigarettes of the invention are made is typically more than about 2.25 percent, generally more than 2.5 percent, often more than about 3 percent, frequently more than about 3.5 percent, and in certain circumstances even more than about 4 percent.

Organic acids useful in this invention are any organic acid or organic compound which behaves as Lewis acids when in contact with nicotine. Examples of organic acids useful in the practice of the present invention include aromatic acids including benzoic type acids and substituted benzoic acids, hydroxy acids, heterocyclic acids, terpenoid acids, sugar acids such as the pectic acids, amino acids, cycloaliphatic acids, dicarboxylic acids, aliphatic acids, keto acids, and the like. Preferred organic acids include the straight and branched chain aliphatic acids; more preferred are the aliphatic monocarboxylic acids and especially the aliphatic keto-monocarboxylic acids. Examples of suitable organic acids include formic, acetic, propionic, isobutyric, butyric, alpha-methylbutyric, isovaleric, beta-methylvaleric, n-caproic, 2-furancarboxylic, phenylacetic, haptic, octanoic, pelargonic, malic, citric, oxalic, malonic, glycolic, succinic, ascorbic, tartaric, fumaric and pyruvic acids, as well as the lower fatty acids (i.e. with carbon chains below C₁₂) and the higher fatty acids (ie, having carbon chains from C12 to C20), and other acids of this type. The most preferred organic acid is an aliphatic gamma-keto acid known as levulinic acid (CH3COCH2CH2COOH). Levulinic acid is also known as acetylpropionic acid, alpha-ketovaleric acid, and 4-oxopentanoic acid. Useful organic compounds having an acidic character include phenols such as guaiacol, vanillin, protocatechualdehyde, and the like.

Many organic acids can improve the taste or aroma of the aerosol, since many organic acids are suitable flavoring agents. However, whether a particular organic acid acts as a flavoring agent depends on the amount of the particular organic acid used as an additive and the taste threshold of the particular acid used. See, for example, Tobacco Flavoring For Smoking Products by Leffingwell et al, pages 11 to 15 (1972). It may be advantageous to use organic acids which impart specific flavor characteristics to the cigarette in small amounts so as not to impart an undesirable bad aftertaste or flavor to the cigarette. For example, the use of certain organic acids in such low amounts may be advantageous so that the cigarette does not have taste or aroma characteristics that may be perceived as chemical, metallic, bitter, pungent or soapy in nature, or as inconsistent with the organoleptic characteristics generally associated with tobacco smoke.

The most preferred organic acid is levulinic acid. Such an organic acid can give the cigarette a smooth, tasty character without giving it any significant disharmonious taste or aroma. If necessary, certain amounts of various other organic acids may be mixed with levulinic acid and used as an additive according to the invention. However, levulinic acid should constitute the major part of the additive consisting of organic acids.

The organic acid additive can be provided in many places in the cigarette. For example, the organic acid or organic acid mixture can be added to the filler material, incorporated into part or all of the filler material, applied to the wrapping material of the tobacco rod, applied within the adhesive line of the wrapping material of the tobacco rod, or incorporated into the filter element of the cigarette, or the like. Optionally, the organic acid additive can be added to processed tobaccos during the manufacture of such materials. For example, the organic acids can be mixed with tobacco extracts or tobacco flavor oils and the resulting mixture of tobacco material and organic acid mixed with other tobacco(s) or tobacco materials or used in another way to treat them. The organic acid can be added to the cigarette or contained in the cigarette in non-dissociated and/or dissociated form (e.g. as carboxylate).

Typically, the organic acid additive is added to the cigarette by mixing the additive with the tobacco material. The method or process for adding the additive may vary depending on whether the additive is added diluted in liquid form or how the additive is placed within the cigarette. For example, the additive may be added using syringes or by methods such as spraying, casing, electrostatic deposition, impregnation, garnish injection, spray drying, encapsulation, and the like.

Suitable solvents for the organic acids include water, ethanol, glycerol, propylene glycol, and the like and combinations thereof.

One or more salts of nicotine and an organic acid may be added to the cigarette. By using such salts, a cigarette with a relatively high nicotine content may be obtained as well as providing the organic acid additive. Such salts may be provided in cigarettes containing tobacco materials with very different nicotine contents.

Preferred organic acid nicotine salts have a molar ratio of the organic acid to nicotine of 1:1, 2:1 or 3:1, most preferably 3:1. The most preferred salts are fully ionic salts of nicotine and the organic acid. Such preferred ionic salts are those salts in which both nicotine nitrogen atoms are protonated by the acid hydrogen atoms of the organic acids. For example, a particularly preferred salt is obtained from one mole of nicotine and 3 moles of levulinic acid and its molar ratio thereof is 1:3.

The nicotine salts of organic acids are conveniently prepared using methods well known to those skilled in the art. Many such methods have been catalogued by Perfetti in Contributions to Tobacco Research International, Volume 12, No. 2, p. 43 (1983), the disclosure of which is also the subject of this application. Preferably, nicotine salts of organic acids are obtained by contacting nicotine with at least the stoichiometric amount of organic acid required to form this specific salt under conditions sufficient to form the salt.

In general, the preferred nicotine organic acid salts are substantially non-volatile under the conditions of manufacture and storage of the smoking articles, but the specific properties of the various salts may vary. For example, nicotine organic acid salts, which are aliphatic acids with branched or unbranched chains having less than 20 carbon atoms, generally have a molar ratio of 1:3 (nicotine:acid) and are liquid under ambient conditions. Such salts normally decompose at temperatures below 100°C, usually between about 50°C and about 60°C. As another example, salts of nicotine and organic dicarboxylic acids generally have a molar ratio of 1:2 (nicotine:acid) and are solid under ambient conditions. Such salts normally decompose at temperatures between about 90ºC and about 120ºC. As yet another example, salts of nicotine and organic acids containing phenyl groups generally have molar ratios of 1:1, 1:2 or 1:3 (nicotine:acid). Normally such salts are solid under ambient conditions. Such salts normally decompose at temperatures between about 110ºC and about 200ºC.

Numerous organic acid nicotine salts can improve the taste and aroma of the aerosol, as many organic acids are suitable flavoring and odorizing agents. Examples of salts that can impart flavor and aroma to the mainstream aerosol at certain amounts include nicotine acetate, nicotine oxalate, nicotine malate, nicotine isovalerate, nicotine lactate, nicotine citrate, nicotine phenylacetate and nicotine myristate. However, it may be advantageous to use salts that impart flavor properties to the cigarette only in small amounts in order to avoid imparting any undesirable bad taste or aroma to the cigarette.

The most preferred salt of nicotine and organic acid is nicotine levulinate. Such a salt can give the cigarette a smooth, pleasant tasting character without imparting any significant disharmonious taste or aroma. If desired, certain amounts of various nicotine salts of organic acids can be mixed with nicotine levulinate and used as the additive in creating the cigarettes according to the invention.

The salts can be added to the cigarette at a variety of locations. For example, the salt can be added to the filler material, incorporated into a portion or all of the filler material, applied to the wrapping material of the tobacco rod, applied within the adhesive line of the wrapping material of the tobacco rod, provided within an area (e.g., a cavity) exposed to heat, or the like.

Typically, the nicotine organic acid salt additive or additive blend is added to the cigarette by admixing the additive with the tobacco material. The method or process for adding the additive may vary depending on whether the additive is added in solid or liquid form, or how the additive is placed within the cigarette. For example, the additive may be added using injection syringes or by methods such as spraying, electrostatic deposition, impregnation, garnish injection, spray drying, encapsulation, and the like.

When applying the nicotine salts of organic acids using spray techniques, it is desirable to form a liquid solution of the salt in a suitable solvent. Such solutions should have a sufficiently low Viscosity to permit spraying or injection of the solution. However, the concentration of the salt in the solution should not be diluted to such an extent that the salt undergoes significant dissociation. Typically, the concentration of the salt in the solution is approximately 20% by weight or more.

Suitable solvents for the salts include water, ethanol, glycerin, propylene glycol and the like, and combinations thereof. In general, most salts of nicotine and organic acids are soluble or miscible in such solvents, and the salts do not undergo significant dissociation when dissolved in small amounts. For example, the salt can be hydrogenated in water without significant dissociation. However, salts diluted with significant amounts of solvent can be dissociated to some extent to be added to the cigarette as a mixture of nicotine salt of organic acids, nicotine and organic acid. Therefore, adding an additive in the form of nicotine and levulinic acid to the cigarette is possible.

Cigarettes may be used as an additive

(i) at least one salt consisting of nicotine and an organic acid, and

(ii) Nicotine

Preferred additives of this type comprise at least one salt with a molar ratio of nicotine to organic acid of 1:3.

The amount of organic acid used in the cigarette can vary. The amount of organic acid contained in the cigarette depends on factors such as the arrangement of the organic acid in the cigarette and the construction of the cigarette. The construction includes the composition and properties of the filter material and the initial mixture of the filler material, the extent of ventilation of the cigarette; and other such factors. For example, for most cigarettes of this invention comprising tobacco material having a total or blend nicotine content of from about 2 percent to about 10 percent, it is desirable to add an organic acid additive to the cigarette in an amount of from about 1 percent to about 10 percent, based on the dry weight of the tobacco filler material, to impart acceptable tobacco flavor, strength, and satisfaction in use. Generally, the amount of organic acid added to such a cigarette will be greater than about 2 percent, often greater than about 3 percent, based on the dry weight of the tobacco filler material in the cigarette.

The amount of nicotine and organic acid salt(s) used in the cigarette can vary. The amount of salt contained in the cigarette depends on factors such as the arrangement of the salt in the cigarette and the construction of the cigarette. For most cigarettes having a tobacco filler material having a nicotine content of about 1 percent to about 2 percent, it is often desirable to add a salt as an additive to give the cigarette a total nicotine content of up to about 8 percent, more usually up to about 4 percent. Such an amount of additive can provide good tobacco flavor, strength and smoking pleasure in use. In general, the amount of nicotine organic acid salt added to a typical cigarette is about 0.25 percent to about 20 percent, preferably about 1.2 percent to about 13 percent of the salt additive based on the dry weight of the tobacco filler material in that cigarette. In certain cases, the use of approximately 3.5 percent or more of the additive salt is desirable, based on the dry weight of the tobacco filler material in the cigarette.

The cigarettes of this invention preferably produce a mainstream aerosol having a pH substantially equal to or lower than that of a similar cigarette having a small amount (e.g., less than 0.2 percent by weight) of the organic acid additive contained therein. In certain circumstances, an amount of an organic acid additive is added to a cigarette to reduce the pH of the mainstream aerosol during its use. The mainstream aerosol is that aerosol which is drawn through the article and into the mouth of the consumer. For example, in a cigarette having smokable tobacco material contained in a confining outer wrapper material, the mainstream aerosol comprises mainstream tobacco smoke with the products of combustion and/or pyrolysis of tobacco material.

The term "mainstream aerosol pH" means the average pH per inhalation of the entire aerosol as measured using the methods described by Sensabaugh et al in Tobacco Science, Volume XI, pages 25-30 (1967), the disclosure of which is also the subject of this application. Typical pH values of the mainstream aerosol of a cigarette average from about 4.5 units to about 8.5 units per cigarette.

By pH reduction of the mainstream aerosol is meant a reduction in the average pH of the mainstream aerosol per particular cigarette. Such a reduction is brought about by adding an effective amount of the additive (e.g. additive consisting of organic acid and/or nicotine salt of organic acids). Typically, the pH reduction is a reduction in the pH by more than about 0.03 pH units, preferably by more than about 0.08 pH units. Normally, the pH reduction of the mainstream aerosol will not make a cigarette which contains mainstream aerosol aerosol with a pH value considerably below 4.5 units.

The presence of the organic acid (which can be created by the decomposition of the nicotine salt of organic acids during use of the cigarette) can cause a pH reduction of the mainstream aerosol, which depends on the amount and type of organic acid contained therein. Therefore, a certain balance, maturation or blending of the flavors culminates in a fuller-bodied tobacco taste, more strength and satisfaction for the consumer. Such a flavor-enhancing property is particularly desirable in high-air dilution or "ultra low tar" cigarettes.

The pH of the mainstream aerosol is affected by several factors. For example, the pH of mainstream cigarette smoke can be affected by factors such as the type of tobacco material or blend of tobacco materials used, the type of processed tobacco (e.g., volume-expanded tobacco or reconstituted tobacco), the construction of the cigarette (e.g., the filter rod material, the degree of air dilution, the circumference of the cigarette, the type of wrapper material, etc.), the manner in which the cigarette is drawn, and other such factors.

Cigarettes according to the invention generally deliver from about 0.2 mg to about 3.5 mg, often from about 0.3 mg to about 2.5 mg, and more often from about 0.4 mg to about 1.5 mg of nicotine when smoked under FTC conditions. Typically, the ratio of FTC "tar" to FTC nicotine in cigarettes of this invention is less than about 12, generally less than about 9, often less than about 7, and in certain cases less than about 5. The ratio of FTC "tar" to FTC nicotine in cigarettes of this invention may be of this invention may be between about 3 and about 6. Typically, the ratio of FTC "tar" to FTC "nicotine" in a cigarette containing a nicotine salt of an organic acid can be reduced by up to about 80 percent of that ratio in a similar cigarette without the salt additive.

The following examples are intended to further illustrate the invention, but should not be construed as limiting its scope. Unless otherwise noted, all parts and percentages are by weight.

EXAMPLE 1

Preparation of a salt of nicotine and levulinic acid by the following process.

Into a 1000 ml round bottom flask is charged approximately 350 g of 1-nicotine obtained from Kodak Laboratory Chemicals, Eastman Kodak Co. (Catalog No. 52, p. 366, Chemical No. 1124973). To the 1-nicotine is added approximately 10 g of sodium hydroxide granules. The flask is fitted with a heating mantle and a magnetic stir bar. The nicotine solution is stirred using a magnetic stirrer. The nicotine is subjected to vacuum distillation using a Todd column filled with glass coils and the fraction distilled at a pressure of 10 mm Hg and a temperature between 97º C and 98º C is collected at a reflux ratio of approximately 10:1. The collected distillate is water clear. The nicotine purified in this way by the vacuum distillation process is used for the production of the salt of 1-nicotine and levulinic acid.

To a 500 mL round bottom flask equipped with a magnetic stir bar and heating mantle is added 69.6 g (0.6 mole) of levulinic acid. The levulinic acid is stirred using a conventional magnetic stirrer. The levulinic acid is obtained from Aldrich Chemical Co., catalog no. 1984-85, p. 672, compound no. L-200-9, and used without further purification. The levulinic acid is heated to approximately 50ºC to obtain a liquid form thereof and the liquefied component is stirred. To the liquefied levulinic acid is added 32.4 g (0.2 mole) of the purified 1-nicotine by titration over a period of approximately 20 minutes. Preferably, the nicotine is introduced into the organic acid to create an environment with an excess of acid in relation to the nicotine and thereby promote salt formation. A clear, viscous, yellow material weighing approximately 100 g is obtained. The product is sealed in a glass ampoule under nitrogen.

The product is 1-nicotine levulinate (as determined by infrared spectrometry) and has a nicotine to levulinic acid ratio of 1:3 (as determined by decomposition distillation in a 10% aqueous sodium hydroxide solution, followed extraction using isopropanol, and gas chromatography analysis for nicotine). The salt is believed to have a structure essentially as generally described in Figure 13 in Peretti, supra.

Cigarettes containing different amounts of the 1-nicotine levulinate salt are manufactured using the following process.

For cigarettes with a length of approximately 99 mm and a circumference of approximately 24.85 mm, the length of the tobacco rod is 68 mm and the length of the filter element is 31 mm.

The tobacco rod comprises a quantity of cut tobacco filler material weighing approximately 0.74 g contained in a cigarette paper restricting wrapper material sold commercially as 754 Cigarette Paper by Ecusta Corp. The filter element is manufactured using conventional cigarette filter manufacturing methods from cellulose acetate rod (2.7 denier per filament, 48,000 denier total) and restricting, air-permeable filter plug wrapper material made of paper having a CORESTA porosity of 26,000 ml/min. The tobacco rod and filter element are arranged so that their ends are in line and adjacent to each other and are firmly connected to each other by tipping paper and tipping paper having a CORESTA porosity of 3135 ml/min. The tipping paper is adhesively attached to the filter element and the adjacent portion of the tobacco rod. The tipping paper describes the length of the filter element and approximately 3 mm of the length of the tobacco rod. Cigarettes so described are manufactured using a Pilot Cigarette Maker from Hauni-Werke Korber & Co. KG. A ring of mechanically created perforations extends around the circumference of the cigarette approximately 13 mm from the outermost part of its mouth end. The perforations thus created result in cigarettes with 50% air dilution. The cigarettes thus produced are designated Samples No. 1, 2, 3, and C-1 according to the sample of filler material from which the respective cigarette was made.

The filler material used to make the tobacco rod consists of rods cut at 32 cuts per inch. The initial filler material comprises a mixture of approximately 9 percent burley tobacco, approximately 41 percent flue-cured tobacco, approximately 32 percent reconstituted tobacco material, and approximately 18 percent oriental tobacco varieties. An aqueous casing substance made of glycerin and flavorings is applied to the mixture.

Four samples of the cut filler mixture, each weighing 1.520 g, are provided. The first sample is treated with 20 g of the 1-nicotine levulinate additive. The second sample is treated with 60 g of the 1-nicotine levulinate additive. The third sample is treated with 100 g of the 1-nicotine levulinate additive. The fourth sample is not treated with the nicotine levulinate additive but is used for comparison purposes.

The addition of the 1-nicotine levulinate additive to the cut filler material is carried out in the form of a spray, using a hand sprayer to apply a mixture of water and additive in a ratio of 1:1.

Each of the four sample lots is placed separately in plastic bags, which are sealed and stored at 70º F for two days. The four sample lots are then each mixed with approximately 480 grams of a cut filler mixture of approximately 75 parts volume expanded burley tobacco and approximately 25 parts volume expanded flue-cured tobacco. The cut and volume expanded filler mixture is added to each sample lot using a mixing drum to obtain a thoroughly mixed mixture having a moisture content of approximately 12 percent to approximately 13 percent. To the mixture obtained from the first sample lot of filler material is added approximately 1 percent of the 1-nicotine levulinate salt (based on the weight of the filler material before treatment) and the mixture is designated Sample No. 1. To the mixture obtained from the second sample of the filler material, approximately 3 percent of the 1-nicotine levulinate salt is added (based on the weight of the filler material before treatment) and the mixture is designated as Sample No. 2. To the mixture obtained from the third sample of the filler material, approximately 5 percent of the 1-nicotine levulinate salt is added (based on the weight of the filler material before treatment) and the mixture is designated as Sample No. 3. The mixture obtained from the fourth sample of the filler material is not treated with the 1-nicotine levulinate salt additive but is used only for comparison purposes and is designated as Sample No. C-1.

The different cigarettes are smoked under FTC conditions. The data for each sample in terms of

(i) FTC Tar, FTC Nicotine, and FTC Carbon Monoxide,

(ii) the ratio of tar to nicotine,

(iii) the nicotine content of the cigarette,

(iv) the number of moves, and

the pH of the mainstream aerosol are presented in Table I. Table I Smoke pH5 Sample FTC Tar (mg/cigarette)¹ FC Nicotine (mg/cigarette)¹ FTC CO (mg/cigarette)¹ Tar/Nicotine² Total Nicotine (%)³ Number of Puffs4 Minimum Maximum *Not an example of the invention

1. Under FTC conditions, every two seconds of pulling (35 ml total volume) is followed by a smoldering phase of 58 seconds.

2. "Tar"/nicotine means the ratio of FTC "tar" to FTC nicotine as delivered by the cigarette.

3. Total nicotine means the total amount of nicotine (i.e. nicotine from all sources present in the cigarette) based on the dry weight of the filler material. See Harvey et al, cited earlier.

4. Number of puffs means the average number of puffs obtained per cigarette under FTC conditions.

5. The pH of the smoke is determined using the procedures described in Sensabaugh et al (referenced above). The minimum and maximum pH values reported for each cigarette represent the calculated averages of the minimum and maximum values per puff obtained from 8 puffs per cigarette.

The data in Table I show that the various cigarettes have increased nicotine content and FTC nicotine levels increase with increasing 1-nicotine levulinate levels. In addition, the ratio of FTC "tar" to nicotine in the examples decreases with increasing 1-nicotine levulinate levels. The various cigarettes all have similar amounts of "tar" and carbon monoxide emitted and a similar number of puffs. Furthermore, the samples of the invention (i.e., Samples Nos. 1-3) have a lower total smoke pH than the sample without exogenous nicotine salt of organic acids (i.e., Sample No. C-1).

Evaluations of the organoleptic properties of Samples Nos. 2, 3 and C-1 show that the cigarette with approximately 5 percent salt additive (i.e. Sample No. 3) has greater potency and smoothness and less roughness than the cigarette without salt additive (i.e. Sample No. C-1). Sample No. 2 does not differ significantly organoleptically from Sample No. C-1 in terms of roughness and overall flavor, although the amount of FTC nicotine in the sample is significantly higher relative to the control sample. Therefore, the nicotine levulinate additive enables the creation of a cigarette with a relatively low ratio of FTC "tar" to FTC nicotine while maintaining a smooth (i.e. not overly rough) flavor.

EXAMPLE 2

Cigarettes containing different amounts of the 1-nicotine levulinate salt are manufactured using the following process.

For cigarettes with a length of approximately 84 mm and a circumference of approximately 24.85 mm, the length of the tobacco rod is 57 mm and the length of the filter element is 27 mm. The tobacco rod comprises a quantity of cut tobacco filler material weighing approximately 0.49 g contained in a cigarette paper confining wrapper material sold commercially as 854 Cigarette Paper by Ecusta Corp. The filter element is manufactured using conventional cigarette filter manufacturing methods from cellulose acetate rod (2.1 denier per filament, 48,000 denier total) and confining, air-permeable paper filter plug wrapper material. The tobacco rod and the filter element are arranged with their ends in line and against each other and are connected together by an air-impermeable tipping paper. The tipping paper is attached to the filter element and the adjacent portion of the tobacco rod with adhesive. The tipping paper circumscribes the length of the filter element and approximately 3 mm of the length of the tobacco rod. Cigarettes so described are manufactured using a Pilot Cigarette Maker manufactured by Hauni-Werke Korber & Co. KG. Laser-generated perforations form a ring around the circumference of the cigarette approximately 13 mm from the outermost part of its mouth end. The perforations penetrate the tipping paper and filter plug wrapper material and are formed by a Laboratory Laser Perforator manufactured by Hauni-Werke Korber & Co. KG. The perforated cigarette has 75% air dilution. Cigarettes so manufactured are designated Sample Nos. 4, 5, 6, and C-2, corresponding to the sample of filler material from which each cigarette was made.

The filler material used to make the tobacco rod consists of rods cut at 32 cuts per inch. The initial filler material comprises a blend of approximately 43 percent Burley tobacco, approximately 6 percent flue-cured tobacco, approximately 19 percent reconstituted tobacco material, and approximately 32 percent Turkish tobacco. An aqueous casing substance made of glycerin and flavorings is applied to the mixture.

Four samples of the cut filler mixture, each weighing 940 g, are provided. The first sample is treated with 60 g of the 1-nicotine levulinate additive. The second sample is treated with 140 g of the 1-nicotine levulinate additive. The third sample is treated with 200 g of the 1-nicotine levulinate additive. The fourth sample is not treated with the nicotine levulinate additive but is used for comparison purposes.

The addition of the 1-nicotine levulinate additive to the cut filler material is carried out in the form of a spray, using a hand sprayer to apply a mixture of water and additive in a ratio of 1:1.

Each of the four sample lots is placed separately in plastic bags, which are sealed and stored at 70º F for two days. Then the four sample lots are each mixed with about 1060 grams of a cut filler mixture of about 35 parts volume expanded burley tobacco and about 65 parts volume expanded flue-cured tobacco. The cut and volume expanded filler mixture is added to each sample lot using a mixing drum to obtain a thoroughly mixed mixture having a moisture content of about 12 percent to about 13 percent. To the mixture obtained from the first sample lot of filler material is added about 3 percent of the 1-nicotine levulinate salt (based on the weight of the filler material before treatment) and the mixture is designated Sample No. 4. To the mixture obtained from the second sample lot of filler material is added approximately 7 percent of the 1-nicotine levulinate salt is added (based on the weight of the filler material before treatment) and the mixture is referred to as Sample No. 5. approximately 10 percent of the 1-nicotine levulinate salt is added (based on the weight of the filler material before treatment) and the mixture is referred to as Sample No. 6. The mixture obtained from the fourth sample of filler material is not treated with the 1-nicotine levulinate salt additive, is used for comparison purposes only, and is referred to as Sample No. C-2.

For comparison purposes, Sample No. C-3 is prepared. Sample No. C-3 is prepared by adding nicotine to a cigarette designated Sample No. C-2. Specifically, approximately 30 mg of a 1:1 mixture of ethanol and 85 percent pure 1-nicotine is injected into the cigarette to give the cigarette a nicotine content of approximately 3.92 percent. The nicotine-ethanol mixture is added to the tobacco rod by inserting a syringe into the end of the rod to be lit and slowly withdrawing it from the rod while injecting the mixture into the rod.

Sample No. 7 is prepared by injecting approximately 10 mg of the ethanol-nicotine mixture described above into a cigarette designated as Sample No. 6 using a syringe in the manner described above. The cigarette thus prepared comprises a nicotine levulinate additive and an exogenous nicotine additive.

The various cigarettes are smoked under FTC conditions. The data regarding

(i) FTC Tar, FTC Nicotine, and FTC Carbon Monoxide,

(ii) the ratio of tar to nicotine,

(iii) the nicotine content of the cigarette,

(iv) the number of moves

for samples Nos. 4 - 6 and C-2 are presented in Table II. In addition, data regarding pH of the mainstream aerosol for samples Nos. 4 - 6, C-2 and C-3 are presented in Table II. Table II pH⁵ of Smoke Sample FTC Tar (mg/cigarette)¹ FTC Nicotine (mg/cigarette)¹ FTC CO (mg/cigarette)¹ Tar/Nicotine² Total Nicotine (%)³ Number of Puffs⁵ Minimum Maximum *Not an example of the invention

1-4 See Table I, footnotes 1-4

5. The pH of the smoke is determined using the procedures described in Sensabaugh et al (referenced earlier). The minimum and maximum pH values reported for each cigarette represent the calculated averages of the minimum and maximum values per puff, respectively. For samples Nos. 4, 5 and C-2, 7 puffs were used to calculate the average pH values. For samples Nos. 6 and C-3, 6 puffs were used to calculate the average pH values.

The data in Table II show that the various cigarettes have increased nicotine content and FTC nicotine levels increase with increasing 1-nicotine levulinate levels. In addition, the ratio of FTC "tar" to nicotine in the samples decreases with increasing 1-nicotine levulinate levels. The various cigarettes all have similar amounts of "tar" and carbon monoxide emitted and a similar number of puffs. In addition, the samples of the invention (i.e., Samples Nos. 4-6) have a lower total smoke pH than the sample without exogenous nicotine salt of organic acids (i.e., Sample No. C-2). In addition, the total smoke pH of Sample No. C-3 is much higher than that of any other sample.

Evaluations of the organoleptic properties of Samples Nos. 5, 6 and C-2 show that the cigarette with approximately 10 percent salt additive (i.e. Sample No. 6) has greater impact and smoothness and less roughness than the cigarette without salt additive (i.e. Sample No. C-2). All cigarettes tested produce good tobacco flavor and have no perceptible chemical off-flavor or uncigarette taste. Surprisingly, Sample No. 5 does not differ significantly organoleptically from Sample No. C-2 in terms of impact, smoothness, roughness and overall flavor, even though the sample delivers a greater amount of FTC nicotine than the control sample. Sample No. C-3 is extremely rough and unpleasant tasting. However, surprisingly, sample No. 7 exhibits a smooth smoke character and pleasant taste, although this sample contains a relatively large amount of exogenous nicotine.

EXAMPLE 3

High nicotine cigarettes containing various amounts of levulinic acid are manufactured using the following process.

For cigarettes having a length of approximately 84 mm and a circumference of approximately 24.85 mm, the tobacco rod length is 57 mm and the filter element length is 27 mm. The tobacco rod comprises an amount of cut tobacco filler material weighing approximately 0.76 g contained in a cigarette paper confining wrapper material sold commercially as 854 Cigarette Paper by Ecusta Corp. The filter element is manufactured using conventional cigarette filter manufacturing methods from cellulose acetate rod (2.1 denier per filament, 48,000 denier total) and confining, air-permeable paper filter plug wrapper material having a CORESTA porosity of 26,000 cm/min. The tobacco rod and the filter element are arranged so that their ends are one behind the other and adjacent to each other and are connected to each other by a porous (air-permeable) tipping paper. The tipping paper is attached to the filter element and the adjacent part of the tobacco rod with adhesive. The tipping material describes the length of the filter element and approximately 4 mm of the length of the tobacco rod. Cigarettes described in this way are manufactured using a Pilot Cigarette Maker from Hauni-Werke Korber & Co. KG. Mechanically created perforations form a ring around the circumference of the cigarette approximately 13 mm from the outermost part of its mouth end. The perforations created in this way result in cigarettes with an air dilution of 75%. The cigarettes thus manufactured are designated as Sample Nos. 8, 9, 10, and C-4, corresponding to the sample of filler material from which the respective cigarette was manufactured.

The filler material for making the tobacco rod consists of rods cut at 32 cuts per inch. The initial filler material comprises a mixture of approximately 40 percent burley tobacco having a nicotine content of approximately 5 percent, approximately 18 percent flue-cured tobacco having a nicotine content of approximately 3.5 percent, approximately 30 percent reconstituted tobacco material having a nicotine content of approximately 0.5 percent, and approximately 12 percent of a blend of oriental tobaccos having a nicotine content of approximately 0.9 percent. An aqueous casing substance comprising glycerin and flavorings is applied to the mixture.

Four samples of the cut filler mixture, each weighing 2000 g on a dry basis, are provided. The first sample is treated with 120 g of the levulinic acid additive. The second sample is treated with 280 g of the levulinic acid additive. The third sample is treated with 400 g of the levulinic acid additive. The fourth sample is not treated with the levulinic acid additive but is used for comparison purposes.

The addition of the levulinic acid additive to the cut filler material is carried out in the form of a spray of a mixture of water and additive using a hand sprayer. The amount of water in the water-additive mixture is such that the cut filler material achieves a final moisture content of approximately 15 percent.

Each of the four samples is placed separately in plastic bags, sealed and stored at 70º F for two days. The four samples are then each filled with approximately 2000 g, by dry weight, of a cut filler mixture of approximately 35 parts volume-expanded Burley tobacco with a nicotine content of approximately 4 percent and approximately 65 parts volume-expanded flue-cured tobacco having a nicotine content of about 4 percent. The mixture of cut and volume-expanded filler material is added to each sample lot using a mixing drum to obtain a thoroughly mixed mixture having a moisture content of about 12 percent to about 13 percent.

To the mixture obtained from the first sample of filler material is added approximately 3 percent of the levulinic acid (based on the dry weight of the filler material) and the mixture is referred to as Sample No. 8. To the mixture obtained from the second sample of filler material is added approximately 7 percent of the levulinic acid (based on the dry weight of the filler material) and the mixture is referred to as Sample No. 9. To the mixture obtained from the third sample of filler material is added approximately 10 percent of the levulinic acid (based on the dry weight of the filler material) and the mixture is referred to as Sample No. 10. The mixture obtained from the fourth sample of filler material is not treated with the additive of levulinic acid, is used for comparison purposes only and is referred to as Sample No. C-4.

The different cigarettes are smoked under FTC conditions. The data for each sample in terms of

(i) the nicotine content of each mixture,

(ii) FTC Tar, FTC Nicotine, and FTC Carbon Monoxide,

(iii) the ratio of tar to nicotine,

(iv) the number of moves, and

(v) the pH of the mainstream aerosol are presented in Table III. Table III Smoke pH⁵ Sample FTC Tar (mg/cigarette)¹ FTC Nicotine (mg/cigarette)¹ FTC CO(mg/cigarette)¹ Tar/Nicotine² Total Nicotine (%)³ Number of Puffs⁵ Minimum Maximum Average⁵ Smoke pH *Not an example of the invention

1-4 See Table I, footnotes 1-4

5. Smoke pH is determined using the procedures described in Sensabaugh et al (references cited earlier). The minimum and maximum pH values reported for each cigarette represent the calculated averages of the minimum and maximum values per puff obtained from 7 puffs per cigarette.

6. The mean smoke pH represents the pH of the twenty-port smoke for the haptstream smoke of 20 cigarettes as determined using the procedures described by Harris et al in 32nd Tob. Chem. Res. Conf. (1978).

The data in Table III show that the various cigarettes with a high nicotine content in the cut filler material (i.e., approximately 3 percent total nicotine in the blend) have similar amounts of FTC "tar", nicotine and carbon monoxide delivered, as well as comparable ratios of FTC "tar" to nicotine and number of puffs. However, cigarettes according to the invention (i.e., Sample Nos. 8-10, which contain the levulinic acid additive) have reduced pH values of the mainstream smoke per puff and on average compared to a control cigarette (i.e., Sample No. C-4, which does not contain the levulinic acid additive). In addition, the data show that the pH of smoke from cigarettes according to the invention decreases significantly with increasing levulinic acid additive content. This reduction in the pH of the smoke from the cigarettes according to the invention suggests a significant increase in the concentration of hydronium ions in the tobacco smoke. Such an increase in the concentration of hydronium ions in the mainstream smoke is sufficient to change the organoleptic quality of the smoke.

The organoleptic evaluation of the samples shows that the cigarettes according to the invention give off a soft smoke, while the smoke of the comparison sample is very harsh. Samples No. 8 and 9 are rated as similarly mild. The cigarettes according to the invention give off good tobacco taste, strength and smoking pleasure. The comparison sample is very strong and the overwhelming feeling it produces is not satisfactory.

EXAMPLE 4

Cigarettes containing varying amounts of levulinic acid are manufactured using the following procedure.

For cigarettes having a length of approximately 84 mm and a circumference of approximately 24.85 mm, the tobacco rod length is 57 mm and the filter element length is 27 mm. The tobacco rod comprises an amount of cut tobacco filler material weighing approximately 0.82 g contained in a cigarette paper confining wrapper material sold commercially as 856 Cigarette Paper by Ecusta Corp. The filter element is manufactured using conventional cigarette filter manufacturing methods from cellulose acetate rod (2.7 denier per filament, 48,000 denier total) and confining, air-permeable paper filter plug wrapper material having a CORESTA porosity of 26,000 cm/min. The tobacco rod and the filter element are arranged so that their ends are one behind the other and adjacent to each other and are connected to each other by a substantially air-permeable tipping paper. The tipping paper is attached to the filter element and the adjacent part of the tobacco rod with adhesive. The tipping material describes the length of the filter element and approximately 4 mm of the length of the tobacco rod. Cigarettes described in this way are manufactured using a Pilot Cigarette Maker from Hauni-Werke Korber & Co. KG. Laser-created perforations form a ring around the circumference of the cigarette approximately 13 mm from the outermost part of its mouth end. The perforations thus created result in cigarettes with an air dilution of 50%. The cigarettes thus produced are designated as Sample Nos. 11, 12, 13, and C-5, corresponding to the sample of filler material from which the respective cigarette was made.

The filler material used to make the tobacco rod consists of rods cut at 32 cuts per inch. The initial filler material comprises a blend of approximately 31 percent Burley tobacco with a nicotine content of approximately 5 percent, approximately 20 percent flue-cured tobacco with a nicotine content of about 3.5 percent, approximately 31 percent reconstituted tobacco material with a nicotine content of about 0.5 percent, and approximately 18 percent of a blend of oriental tobaccos with a nicotine content of about 0.9 percent. An aqueous casing substance comprising glycerin and flavorings is applied to the blend.

Four samples of the cut filler mixture, each weighing 3120 g on a dry basis, are provided. The first sample is treated with 40 g of the levulinic acid additive. The second sample is treated with 120 g of the levulinic acid additive. The third sample is treated with 200 g of the levulinic acid additive. The fourth sample is not treated with the levulinic acid additive but is used for comparison purposes.

The addition of the levulinic acid additive to the cut filler material is carried out in the form of a spray of a mixture of water and additive using a hand sprayer. The amount of water in the water-additive mixture is such that the cut filler material achieves a final moisture content of approximately 15 percent.

Each of the four sample lots is placed separately in plastic bags, which are sealed and stored at 70º F for two days. Then the four sample lots are each mixed with approximately 880 grams, by dry weight, of a cut filler blend of approximately 35 parts volume expanded Burley tobacco having a nicotine content of about 4 percent and approximately 65 parts volume expanded flue-cured tobacco having a nicotine content of about 4 percent. The cut and volume expanded filler blend is added to each sample lot using a mixing drum. added to obtain a thoroughly mixed mixture having a moisture content of about 12 percent to about 13 percent.

To the mixture obtained from the first sample of filler material is added approximately 1 percent of the levulinic acid (based on the dry weight of the filler material) and the mixture is referred to as Sample No. 11. To the mixture obtained from the second sample of filler material is added approximately 3 percent of the levulinic acid (based on the dry weight of the filler material) and the mixture is referred to as Sample No. 12. To the mixture obtained from the third sample of filler material is added approximately 5 percent of the levulinic acid (based on the dry weight of the filler material) and the mixture is referred to as Sample No. 13. The mixture obtained from the fourth sample of filler material is not treated with the additive of levulinic acid but is used only for comparison purposes and is referred to as Sample No. C-5.

The different cigarettes are smoked under FTC conditions. The data for each sample in terms of

(i) the nicotine content of each mixture,

(ii) FTC Tar, FTC Nicotine, and FTC Carbon Monoxide,

(iii) the ratio of tar to nicotine,

(iv) the number of moves, and

(v) the pH of the mainstream aerosol

are presented in Table IV. Table IV Smoke pH⁵ Sample FTC Tar (mg/cigarette)¹ FTC Nicotine (mg/cigarette)¹ FTC CO (mg/cigarette)¹ Tar/Nicotine² Total Nicotine (%)³ Number of Puffs⁵ Minimum Maximum Average⁵ Smoke pH *Not an example of the invention

1-4 See Table I, footnotes 1-4

5. Smoke pH is determined using the procedures described in Sensabaugh et al (references cited earlier). The minimum and maximum pH values reported for each cigarette represent the calculated averages of the minimum and maximum values per puff obtained from 7 puffs per cigarette.

6. The mean smoke pH represents the pH of the twenty-port smoke for the haptstream smoke of 20 cigarettes as determined using the procedures described by Harris et al, supra.

The data in Table IV show that the various inventive cigarettes with a high nicotine content in the cut filler material (i.e., greater than 2.5 percent total nicotine in the blend) have similar amounts of delivered FTC "tar", nicotine and carbon monoxide as the control cigarette. The various cigarettes also have a comparable ratio of FTC "tar" to nicotine and a comparable number of puffs. However, inventive cigarettes (i.e., Sample Nos. 11-13, which contain the levulinic acid additive) have reduced pH values of the mainstream smoke, per puff and on average, compared to a control cigarette (i.e., Sample No. C-5, which does not contain the levulinic acid additive).

The organoleptic evaluation of the samples shows that the cigarettes according to the invention give off a soft smoke, while the smoke of the comparison sample is very harsh. Samples No. 12 and 13 are rated as similarly mild. The cigarettes according to the invention give off good tobacco taste, strength and smoking pleasure. The comparison sample is very strong and the overwhelming feeling it produces is not satisfactory.

EXAMPLE 5

Cigarettes containing varying amounts of levulinic acid are manufactured using the following procedure.

For cigarettes having a length of approximately 84 mm and a circumference of approximately 24.85 mm, the length of the tobacco rod is 57 mm and the length of the filter element is 27 mm. The tobacco rod comprises a quantity of cut tobacco filler material weighing approximately 0.82 g and contained in a confining wrapping material of cigarette paper, which is referred to as 856 Cigarette Paper sold commercially by Ecusta Corp. The filter element is manufactured using conventional cigarette filter manufacturing methods from cellulose acetate strand (2.7 denier per filament, 48,000 denier total) and restrictive, air-permeable filter plug wrapping material made of paper with a CORESTA porosity of 26,000 cm/min. The tobacco rod and the filter element are arranged so that their ends are one behind the other and adjacent to each other and are connected to one another by a substantially air-permeable tipping paper. The tipping paper is attached to the filter element and the adjacent portion of the tobacco rod with adhesive. The tipping material defines the length of the filter element and approximately 4 mm of the length of the tobacco rod. Cigarettes so described are manufactured using a Pilot Cigarette Maker manufactured by Hauni-Werke Korber & Co. KG. The cigarettes thus created are designated Sample No. 14, 15, 16, and C-6, corresponding to the sample of the core material from which each cigarette was made.

The filler materials used to make the tobacco rods for Samples Nos. 14, 15, 16 and C-6 are the filler materials used for Samples Nos. 11, 12, 13 and C-5, respectively.

The different cigarettes are smoked under FTC conditions. The data for each sample in terms of

(i) the nicotine content of each mixture,

(ii) FTC "tar", FTC nicotine,

(iii) the ratio of tar to nicotine,

(iv) the number of moves, and

(v) the pH of the mainstream aerosol

are presented in Table V. Table V Sample FTC Tar (mg/cigarette)¹ FTC Nicotine (mg/cigarette)¹ Tar/Nicotine² Total Nicotine (%)³ Number of Puffs⁴ Average Smoke pH⁴ *Not an example of the invention

1-4 See Table I, footnotes 1-4

5. The mean smoke pH represents the pH of the twenty-port smoke for the haptstream smoke of 20 cigarettes as determined using the procedures described by Harris et al., supra.

The data in Table V show that the various cigarettes of the invention having a high nicotine content in the cut filler material (i.e., greater than 2.5 percent total nicotine in the blend) have similar amounts of delivered FTC "tar" and nicotine as the control cigarette. The various cigarettes also have a comparable ratio of FTC "tar" to nicotine and a comparable number of puffs. However, cigarettes of the invention (i.e., Sample Nos. 14-16, which contain the levulinic acid additive) have a reduced average smoke pH as compared to a control cigarette (i.e., Sample No. C-6, which does not contain the levulinic acid additive).

The organoleptic evaluation of the samples shows that the cigarettes according to the invention give off a soft smoke, while the smoke of the comparison sample is very harsh. Samples No. 15 and 16 are rated as similarly mild. The cigarettes according to the invention give off good tobacco taste, strength and smoking pleasure. The comparison sample is very strong and the overwhelming feeling it produces is not satisfactory.

Claims (11)

1. Cigarette containing smokable material contained within a confining outer wrapping material, the cigarette (i) a ratio of FTC tar to FTC nicotine of less than 9; (ii) a nicotine content of more than 2.25%, based on the dry weight of the smokable material, and (iii) more than 1%, based on the dry weight of the smokable material, of levulinic acid in dissociated and/or non-dissociated form has. 2. Cigarette according to claim 1, the nicotine content of which, based on the dry weight of the smokable material, is greater than 2.5%. 3. Cigarette according to claim 1, the nicotine content of which, based on the dry weight of the smokable material, is greater than 3%. 4. Cigarette according to claim 1, 2 or 3, whose levulinic acid content, based on the dry weight of the smokable material, is greater than 2%. 5. Cigarette according to claim 1, 2 or 3, whose levulinic acid content, based on the dry weight of the smokable material, is greater than 3%. 6. Cigarette according to one or more of the preceding claims, in which substantially all of the levulinic acid is in non-dissociated form. 7. Cigarette according to one or more of claims 1 to 5, in which at least part of the levulinic acid is in the form of nicotine levulinate. 8. Cigarette according to one or more of claims 1 to 7, which has a ratio of FTC "tar" to FTC nicotine of less than 7. 9. A cigarette according to claim 1, which has a ratio of FTC "tar" to FTC nicotine of 3 to 6. 10. Cigarette according to one or more of the preceding claims, in which the smokable material is a mixture of tobacco materials. 11. Cigarette according to one or more of the preceding claims, which has a filter element in which at least part of the levulinic acid is located.