US3577997A - Tobacco treatment with citric acid and deuterium oxide - Google Patents

Tobacco treatment with citric acid and deuterium oxide Download PDF

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US3577997A
US3577997A US809004A US3577997DA US3577997A US 3577997 A US3577997 A US 3577997A US 809004 A US809004 A US 809004A US 3577997D A US3577997D A US 3577997DA US 3577997 A US3577997 A US 3577997A
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tobacco
citric acid
smoke
cigarettes
deuterium oxide
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US809004A
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Max August Helmut Bindig
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American Chemosol Corp
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American Chemosol Corp
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    • A—HUMAN NECESSITIES
    • A24—TOBACCO; CIGARS; CIGARETTES; SIMULATED SMOKING DEVICES; SMOKERS' REQUISITES
    • A24B—MANUFACTURE OR PREPARATION OF TOBACCO FOR SMOKING OR CHEWING; TOBACCO; SNUFF
    • A24B15/00—Chemical features or treatment of tobacco; Tobacco substitutes, e.g. in liquid form
    • A24B15/18—Treatment of tobacco products or tobacco substitutes
    • A24B15/24—Treatment of tobacco products or tobacco substitutes by extraction; Tobacco extracts
    • A24B15/241—Extraction of specific substances
    • A24B15/246—Polycyclic aromatic compounds
    • A—HUMAN NECESSITIES
    • A24—TOBACCO; CIGARS; CIGARETTES; SIMULATED SMOKING DEVICES; SMOKERS' REQUISITES
    • A24B—MANUFACTURE OR PREPARATION OF TOBACCO FOR SMOKING OR CHEWING; TOBACCO; SNUFF
    • A24B15/00—Chemical features or treatment of tobacco; Tobacco substitutes, e.g. in liquid form
    • A24B15/18—Treatment of tobacco products or tobacco substitutes
    • A24B15/28—Treatment of tobacco products or tobacco substitutes by chemical substances
    • A24B15/42—Treatment of tobacco products or tobacco substitutes by chemical substances by organic and inorganic substances

Definitions

  • This invention relates to the treatment of tobacco and relates more particularly to a technique for processing tobacco in order to reduce the quantity of various undesirable constituents, particularly benzo(a)pyrene, in the smoke resulting from pyrolysis of a treated tobacco charge in smoking products, particularly cigarettes, manufactured with such tobacco compositions.
  • this invention is concerned with the carcinogenicity of certain smoke constituents and thus, an understanding of materials believed to cause cancer and the activity thereof in connection with smoking is a basic prerequisite to an appreciation of the invention. Similarly, the significance of the results achieved with the invention are understood by comparison results with certain accepted testing procedures, and more particularly, rodent tests. Accordingly, the background on cancer-producing materials and cancer tests is set forth initially.
  • Cancer is a malignancy of pathologically changed cells which begins locally, grows in neighboring tissues and is carried throughout the body by the blood stream or lymph tract. Such pathogenic cells can form off-shoot tumors in remote regions of the body, a process known as metastasis. The entire organism can be thus affected depending upon the malignancy, location and size of such tumors.
  • Cigarette smoke is known to be a heterogeneous mixture of various materials including minute particles of liquid, uncondensed vapors and gases. When it reaches the smokers mouth, smoke is a concentrated aerosol with millions or billions of tiny particles, on the order of 0.5 microns in individual median size, per cubic centimeter.
  • Chemical composition and biological properties of smoke are ordinarily investigated by separating the same into a particulate phase and a gaseous phase, the gaseous phase frequently being further subdivided into materials which condense at liquid-air temperature and those which do not.
  • the large quantities of material required for investigation of the chemical constituents are prepared on smoking machines in which many cigarettes are smoked simultaneously in a fashion designed to simulate average smoking habits.
  • a yellow-brown condensate known as tobacco tar is collected in traps with the traps being cooled to the temperature of dry ice (-70 C.) or liquid nitrogen (196 C.).
  • the tar thus contains all of the particulate phase of the smoke as well as condensable components of the gaseous phase.
  • the amount of tar from the smoke of one cigarette is generally between 3 and 40 milligrams, the quantity varying according to the burning and condensing conditions, the length of the cigarette, the use of a filter, the porosity of the cigarette paper, the content of tobacco, and the weight and kind of tobacco.
  • components of the particulate phase include higher polycylic aromatics, aliphatic and alicyclic hydrocarbons, terpenes and isoprenoid hydrocarbons, alcohol and esters, sterols, aldehydes and ketones, acids, phenols and polyphenols, alkaloids, nitrogen bases, heterocyclics, amino acids and inorganic chemicals such as arsenic, potassium and some metals.
  • benzo(a)pyrene (occurs as l,2-benzopyrene; also called 3,4-benzpyrene and benz(e)pyrene, 4,5-benzopyrene is one of the most potent carcinogens detected in tobacco smoke and is present in much larger quantities than any of the other compounds identified to date.
  • This material has been well known as a carcinogen for some time since it is present in coal tar, i.e., the tar formed on carbonization of coal.
  • the smoke condensates from all smoked tobacco compositions include a quantity of benzo(a)pyrene which is detectable by well-known qualitative techniques and which is present in sufficient quantities to be a hazard to health as a tumor-inducing material. It has been suggested that the reduction of benzo(a)pyrene would inhibit the tumorigenicity of tobacco smoke condensate, benzo(a)pyrene being the accepted indicator for tumor-initiating aromatic hydrocarbons. See, for example, Reduction of Tumorigenicity of Cigarette Smoke, Wynder et al. JAMA, Vol. 192, No. 2, Apr. 12, 1965, pp. 96l02.
  • this invention in general, is directly concerned with the reduction of the biologically undesirable constituents of cigarette smoke without substituting any similarly noxious substances therefore, thereby in effect, leading to the production of a safer cigarette.
  • the procedures for manufacturing cigarettes and the like having the improved properties set forth above do not result in taste losses, and require only relatively small additional capital investments for equipment.
  • the invention permits the utilization of particular compositions and techniques. the cost of which would not in any way be prohibitive to the adoption of such procedures by the industry.
  • the tobacco treating compositions hereof are nonresidual biologically and probably do not survive pyrolization in any form other than carbon dioxide and water. Further, the extremely small quantities utilized will not appreciably alter the weight of the tobacco.
  • the basic techniques hereof comprise spraying a tobacco composition with a treating material comprising a solution of a mixture of effective quantities of citric acid and deuterium oxide.
  • a treating material comprising a solution of a mixture of effective quantities of citric acid and deuterium oxide.
  • citric acid was dissolved in distilled water to a total of milliliters and l milliliter of deuterium oxide was then added.
  • 0.2 milliliter of stock solution was diluted to l to 2 liters final volume with distilled water. Dilution with distilled water regularly gives a pH of 4.5 to 5.5 at between 1 and 2 liters final volume. It is found that within this pH range tobacco flavor and aroma are not appreciably altered.
  • Shredded tobacco of conventional American blend ready for manufacture into cigarettes was used. Such tobacco ordinarily contains various flavoring ingredients and various humectants, depending on the manufacture. While the particular humectants may vary with different manufacturers, such additives are always included to provide the tobacco with adequate water retention properties for commercial purposes.
  • Tobacco ready for manufacture into cigarettes generally has a relative humidity of approximately 50 percent plus or minus a few percent since unduly dry tobacco is generally not acceptable to the smoking public. In any event, the humidity of the tobacco should be adjusted to a range of about 48 or 50 percent to about 60 percent, if necessary, since the optimum results from use of the instant inventive concepts are realized by starting with tobacco of this type. Additionally, humidity control provides a simple measure for quantifying the treating solution added to the tobacco according hereto.
  • the relatively high humidity insures complete impregnation of the tobacco with the treating solution.
  • the use of a humidity at this level causes no difficulty since, as indicated, ordinary tobacco ready for manufacture into cigarettes has a relative humidity of about 48 or 50 percent to satisfy other commercial requirements.
  • Compressed inert gas preferably nitrogen
  • oxygen or other propellants may be substituted therefor.
  • a fine wetspray nozzle was employed with 4 atmospheres pressure of propellant gas. However, this is not a critical factor.
  • spraying tobacco with the aforementioned diluted solution was quantified by humidity control. The initial humidity was elevated by the spray liquid minimally to a reading 20 percent greater than the original humidity.
  • composition as set forth above comprised approximately a 10 percent citric acid and deuterium oxide solution diluted to a pH of about 5 and quantitatively controlled by humidity elevation, it has been found that other concentrations of solution and other quantity controls are useful.
  • This solution then has a weight ratio of about 1:10 deuterium oxide/citric acid as compared to a 1:1 solution as used in the preferred procedure described above.
  • the quantities of the active ingredients are relatively minute whereby it would appear as if substantial variation in the actual quantities utilized should not be expected to significantly modify the resultant properties of the tobacco or the condensates resulting from smoking the same.
  • the ratio of citric acid to tobacco may vary as much as from 1 mg. to 100 mg. citric acid/tobacco for 5000 cigarettes. Since the average cigarette includes approximately 1 to 1.1 g. tobacco the citric acid is present in from about 1 mg. to 100 mg. to about 5 kg. tobacco.
  • the deuterium oxide may be present in similar or even smaller proportions. Thus, the extremely small amounts of treating solution necessary to produce the desired results is believed evident.
  • the solution described hereinabove can be prepared at ordinary room temperatures and is preferably applied to the tobacco as a spray.
  • conventional tobacco treating techniques are used except the solution is preferably sprayed onto the tobacco after the roasting or toasting operation at a location prior to the wrapping of the tobacco in the manufacture of a cigarette and at a point where the heated tobacco has sufficiently cooled so that it does not evaporate the spray solution.
  • a location where the tobacco has reached a temperature of approximately 30 C. or less that is, when the tobacco approaches room temperature, can be expected to be quite satisfactory. Substantially higher temperatures might evaporate the solution or make application of the same more difficult.
  • Spraying of the solution may be carried out in a flavor drum situated after the roasting equipment.
  • other equivalent spraying equipment may be utilized in lieu of the flavor drum. It is to be pointed out that this spray equipment is basically the only additional investment which would be required for the use of the instant process whereby such a technique can be readily integrated with conventional cigarette manufacturing procedures in the absence of significant increase in costs.
  • the particles should be of such a size that they would not tend to float or become suspended in the surrounding atmosphere. In other words, during the spraying technique, the particles should relatively quickly come in direct contact with the tobacco and impregnate the same.
  • the solution is preferably used at a pH of between about 4.5 and 5.5. While this pH can be modified somewhat, a pH substantially below 4 will ordinarily adversely affect the taste and flavor of the treated tobacco. Therefore, this lower limit becomes somewhat important from a practical viewpoint. in fact, in order to produce optimum test characteristics, a pH of approximately is significant. Similarly, a maximum limit. of about pH 6 is basically governed by practical considerations in that a solution having less acidity would be undesirably weak whereby it would become necessary to add an excessive amount of the solution to the tobacco mixture thereby increasing the moisture content of the same to a point which is not commercially desirable.
  • Example 1 it will accordingly be understood that although the procedure set forth in Example 1 is preferred from all standpoints, various modifications can be made thereto by those skilled in the art without departing from the instant inventive concepts. Additionally, it is quite possible that various chemically similar materials can be substituted for the ingredients of the composition set forth hereinabove while producing a similar result, although the time and expense in determining the available alternatives has not permitted such an investigation to date. However, it is now known that use of a aqueous citric acid solution alone or use of an aqueous deuterium oxide solution alone at least in the aforementioned concentrations rather than use of a mixed solution as set forth above will not produce the desirable modification of the smoke condensates to be discussed in more detail hereinafter, specifically, reduction of benzo(a)pyrene and health hazards.
  • Example 2 Utilizing conventional single cigarette, manually powered devices for manufacture of cigarettes, approximately 125,000 cigarettes were produced with tobacco treated according to the preferred technique of Example 1 and an additional 125,000 cigarettes were produced utilizing untreated tobacco of the same blend. Separate machines of identical construction were employed to make cigarettes from the treated and untreated tobaccos. Cigarettes were manufactured from each sample in identical fashion and with identical mean weights of tobacco. The cigarettes were 80 mm. overall, 63 mm. of which was tobacco, the remainder being a conventional cellulose acetate filter. Each cigarette weighted about 1 gram. The two batches of cigarettes were kept under identical conditions of temperature and humidity control.
  • the 250,000 cigarettes were smoked in a conventional 40-port cigarette smoking machine.
  • Cigarettes containing treated and untreated tobacco were smoked separately and the smoking machine was completely overhauled and cleaned between successive batches.
  • the cigarettes were smoked utilizing the techniques commonly accepted for such procedures, that is,.a standard rate of one puff per minute of 2 seconds duration and 35 ml. volume, to within about 10 mm. of the filter.
  • the smoke residues were collected on Cambridge fiberglass filters with no more than 5 residues being collected on any one Cambridge filter.
  • the vapors which bypassed the Cambridge filters were trapped in flasks immersed in dry ice.
  • the Cambridge filter and cold trap residues were combined separately for the 125,000 treated and for the 125,000 untreated cigarettes.
  • The,respectively separate residues were worked up in batches representing 500 cigarettes each.
  • the filter pad was resuspended in one liter of cyclohexane and filtered as before. This extract was then added to the separatory funnel for partitioning.
  • a long stem funnel was inserted through the top and through the upper cyclohexane layer into the methyl alcohol layer. About 2530 ml. of distilled water was slowly added and a light brown emulsion appeared at the bottom of the funnel.
  • the cyclohexane was evaporated in a conventional spherical evaporating vessel wherein the vessel is rotated in a warm water bath to prevent uneven heating, the bath temperature being at about 56 C. Vacuum was produced by a conventional aspirator and was allowed to build up about one minute. The flask was then rotated, slowly at first to prevent bumping, then more rapidly.
  • cigarettes formed with the tobacco treated according to the preferred technique of Example 1 were found to produce reduced nicotine content as compared with cigarettes incorporating untreated tobacco of the same blend, the treated condensates, on the average, containing approximately 78 percent of the nicotine in the untreated condensates, although total solids content was not significantly changed. In view of the known undesirable effects of nicotine, this reduction in nicotine content has obvious significance.
  • the percent reduction is based on a comparison with the amount of 3,4 benzo(a)pyrene obtained from a control of the same tobacco composition:
  • the initial humidity can also vary substantially while producing a benzo(a)pyrene reduction, but once again, optimum results are obtainable with tobacco having a conventional initial humidity level of approximately 50 percent.
  • incorporation of conventional humectants in the tobacco composition is important to provide the optimum treatment according to this invention, such additives also being necessary for commercial production of cigarettes or the like from the tobacco in order to provide adequate water retention.
  • the most effective processing conditions according to this invention from the standpoint of temperature, humectant additives and initial an final humidity levels correspond with the most desirable conditions for commercial production of cigarettes whereby the techniques of this invention may be readily integrated with present production procedures.
  • the treated cigarettes hereof were found to be at least as desirable from a taste and aroma standpoint to the smoker as their regular brand, without exception. Additionally, a reduction in cough and irritation was observed when smoking cigarettes having tobacco treated according hereto as compared with their regular brand. it is believed that the modification of the combustion products caused by the tobacco treatment hereof accounts for this reduction in cough and irritation.
  • BIOLOGICAL TESTS Total cigarette residues trapped in sesame oil were used for injection experiments. The only modification of the residues was removal of nicotine in all instances by conventional techniques since rodents are hypersensitive to nicotine poisoning and would be killed by nicotine present in smoke residues tested in quantities large enough to be significant.
  • condensates were immediately taken into solution and prepared in the sesame oil for subcutaneous injection in the manner to be described in detail hereinafter. Smoking was continued throughout these biological tests and the aforedescribed chemical tests so that only fresh condensate would be used. Consequently, condensate was never stored in large quantities or for long times. In some instances small quantities of condensates were stored for short periods, never in excess of 48 hours, and such condensates were refrigerated during storage and warmed to ambient temperatures before use.
  • mice were CF-l (Carworth) inbred, tumor-resistent mice. Both males and females were used, selected at identical ages and average weights with the view to observing growth and weight-gain alterations.
  • mice A total of 150 mice were divided into three experimental groups, as follows:
  • Group A In this Group of 50 mice, each animal received 0.1 ml. injection of pure sesame oil from the batch used in Groups B and C each day for days (No tobacco smoke condensate was added).
  • Group B In this Group of 50 mice each animal received 0.1 ml. of smoke condensate (less nicotine) from five cigarettes containing tobacco treated according to Example 1 each day for 10 days.
  • Group C In this Group of 50 mice each animal received 0.1 ml. of smoke condensate (less nicotine) from five untreated cigarettes each day for 10 days.
  • mice were examined daily. No noticeable changes occurred with all mice remaining healthy until the 14th day when approximately one-fifth of the mice of Group C were noted to have beginning ulceration at the injection site.
  • the mice of Groups A and B appeared normal at that time. By the 20 day, one-fourth of the mice of Group C had ulcerations of injection sites with definite loss of hair.
  • the mice of Groups A and B were normal 5 weeks from the start of the experiment.
  • Biopsies of the ulcerated areas and subsequent sloughs in animals receiving higher concentrations of cigarette concentrates showed microscopic changes of intense inflammatory reaction with vascular thrombosis and necrosis of all tissues in the area resulting in a slough of the tissues.
  • Biopsies of multilobulated masses occurring in all three Groups showed a temporary pseudocyst formation with no characteristic pathological change.
  • mice The injected material in each Group of mice was the total smoke condensate (less nicotine) from five cigarettes.
  • mice Sesame oil controls of equal injected volumes were established on all experiments). At each level, paired animals were injected with residues from tobacco treated according hereto and with untreated cigarette residues of the same brand. Observations on these mice are divided into two types:
  • the toxic mortality from 100 cigarettes X 10 daily injection animals was 50 percent from both residue from treated and untreated tobacco.
  • treatment of tobacco according to this invention yields a decided decrease in toxic mortality in experimental animals over that which results from the residues of smoke from the same but untreated tobacco.
  • Vascular impairment and local tissue destruction from 25 cigarettes X 10 daily injection animals was zero in the sesame oil controls and the treated tobacco residue injected mice.
  • the untreated residues produced vascular occlusion and tissue death at the injection site in 100 percent of the animals at the fourteenth to sixteenth day.
  • Vascular impairment and local tissue destruction from 50 cigarettes X 10 daily injection animals was percent in treated tobacco residue mice and percent in the untreated ones.
  • Vascular impairment and local tissue destruction from 100 cigarettes X 10 daily injection animals was 100 percent regardless of the treatment of the tobacco.
  • the lowest dosage level assayed does not produce arterial occlusion and tissue death, if the tobacco is treated according to the instant inventive concepts.
  • This protective effective persists above the 25 cigarette per injection level. Protection provided by the treatment hereof against vascular impairment and tissue destruction is therefore of an order of magnitude of fiveto ten-fold.
  • mice Three groups of 100 mice each were treated in the manner of Groups A, B and C described above and were observed for a 60-week period.
  • a 40-port automatic smoking machine was used to smoke" both the treated and untreated cigarettes. Standardized, internationally accepted specifications for the smoking-volume of puff, time, interval, etc. were met. Total smoke condensates were collected in dry ice traps. No Cambridge filters were used. The whole condensate, without physical or chemical separation, was used. Condensates were collected in single glass containers for each 500 cigarettes smoked. They were refrigerated until use, at which time condensates were taken up in acetone for application to the skin. The smoking, the collection of smoke condensate and their application to skin all were in continuous operation throughout the experimental period. Equal numbers of treated and untreated cigarettes were smoked. The smoking machine was dismantled and new tubing and glassware substituted before each change from treated to untreated cigarettes.
  • the CF mice used in this experiment were housed in metal cages in air-conditioned (temperature/humidity forced air controlled), isolated rooms at 25C. without central air returns. No other experimental animals were permitted in the rooms used, and there was no change in laboratory personnel. Sawdust bedding and Purina Fox Chow Checkers ad lib, with water ad lib was provided. indirect daylight in equal intensity reached all cages; there was no exposure to bright sources of artificial light. All mice were 21 days old at the commencement of the experiments. All experimentscontrols, treated and untreated-were run concurrently for a 60-week experimental period.
  • a shaved area 1.5 cm. by 2.0 cm. in the mid-dorsal skin was selected for each animal.
  • a 04 Camels hair brush was used to paint the whole condensate on this area.
  • the volume of solvent (acetone) was not varied between controls and the experimental groups. All groups were painted on the same days, using different equipment. Excess condensates in acetone were discarded at the end of each days application.
  • mice Groups of 50 mice each were given, by dermal painting, the following applications three times weekly:
  • a volume of acetone equal to the volumes of B and C groups for each application.
  • mice which serve as overall controls, received only acetone, In this group there were no malignancies produced within the painted skin zone.
  • mice which received dermal paintings with untreated tobacco whole condensates, developed malignancies in 25 percent of the animals within the painted skin zone.
  • Group B mice which received dermal paintings with treated tobacco whole condensates, developed no malignancies within the painted zone.
  • the overall irritation from heavy (three or more packs daily) cigarette smoking resulting from the use of tobacco treated according to this invention is substantially reduced, especially the productive cough ordinarily induced in many subjects by cigarette smoking.
  • the toxicity of the treating material hereof is not found to be any problem there being no metabolic residual matter and only reagent grade, naturally occuring substances being utilized.
  • smoke condensates from tobacco treated according hereto have less 3,4 benzo(a)pyrene, a factor which is of extreme significance considering the known carcinogenic effect of this material, and biological tests confirm that such treated tobacco produces smoke condensates which can be expected to be significantly less hazardous to health, based on results in experimental animals.
  • a method of processing tobacco comprising treating the tobacco with a material including a mixture of citric acid and deuterium oxide in quantities sufficient to reduce the quantity of benzo(a)pyrene in smoke resulting from pyrolysis of the tobacco.
  • said material is an aqueous solution having a pH of between about 4 and 6, said deuterium oxide being present in from about 10 to about percent by weight of said citric acid.
  • said material comprises an aqueous solution of about 1 gram of citric acid and 1 milliliter of deuterium oxide in 10 milliliters of water diluted to provide said solution with a pH of between about 4.5 and 5.5, further comprising the steps of initially adjusting said tobacco to a humidity of from about 50 to about 60 percent, an spraying said aqueous solution onto said tobacco in sufficient quantities to raise the humidity of said tobacco by at least about 20 percent.
  • a smoking article including a tobacco charge adapted to be ignited and smoked, the tobacco composition in said charge including a sufficient amount of a mixture of citric acid and deuterium oxide to reduce the benzo(a)pyrene content in smoke resulting from pyrolysis of the tobacco composition.
  • a tobacco composition comprising tobacco and a sufficient amount of a mixture of citric acid and deuterium oxide to reduce the benzo(a)pyrene content in smoke resulting from pyrolysis of the tobacco.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • General Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • Manufacture Of Tobacco Products (AREA)
US809004A 1969-03-20 1969-03-20 Tobacco treatment with citric acid and deuterium oxide Expired - Lifetime US3577997A (en)

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US (1) US3577997A (fr)
BR (1) BR6908558D0 (fr)
CH (1) CH536608A (fr)
DE (1) DE1915785A1 (fr)
ES (1) ES366409A1 (fr)
FR (1) FR2033668A5 (fr)
IL (1) IL32006A0 (fr)
IT (1) IT982339B (fr)
NL (1) NL6905868A (fr)
OA (1) OA03464A (fr)
ZA (1) ZA692659B (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3863645A (en) * 1974-06-11 1975-02-04 Us Agriculture Process for treating tobacco
US4215706A (en) * 1978-10-13 1980-08-05 Loew's Theatres, Inc. Nicotine transfer process
US20040112394A1 (en) * 2002-07-18 2004-06-17 Val Krukonis Reduction of constituents in tobacco

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2971517A (en) * 1958-06-30 1961-02-14 Arenco Ab Process for the preparation of an insoluble tobacco sheet or web
US3003895A (en) * 1957-12-06 1961-10-10 Heinr Borgwaldt Tobacco product and method of making the same
US3106210A (en) * 1957-11-18 1963-10-08 Reynolds Metals Co Smoking tobacco
US3112755A (en) * 1960-12-19 1963-12-03 Lorillard Co P Tobacco product
US3126011A (en) * 1964-03-24 Tobacco composition and smoking unit
US3380458A (en) * 1966-02-15 1968-04-30 Eastman Kodak Co Method for producing a cigarette with low tar yield

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3126011A (en) * 1964-03-24 Tobacco composition and smoking unit
US3106210A (en) * 1957-11-18 1963-10-08 Reynolds Metals Co Smoking tobacco
US3003895A (en) * 1957-12-06 1961-10-10 Heinr Borgwaldt Tobacco product and method of making the same
US2971517A (en) * 1958-06-30 1961-02-14 Arenco Ab Process for the preparation of an insoluble tobacco sheet or web
US3112755A (en) * 1960-12-19 1963-12-03 Lorillard Co P Tobacco product
US3380458A (en) * 1966-02-15 1968-04-30 Eastman Kodak Co Method for producing a cigarette with low tar yield

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
Tang & Mathur Deuterium Isotope Effects on Dissociation Constants and Formation Constants, from Journal of Physical Chemistry (1961) No. 65, pg. 1074 1076 *

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3863645A (en) * 1974-06-11 1975-02-04 Us Agriculture Process for treating tobacco
US4215706A (en) * 1978-10-13 1980-08-05 Loew's Theatres, Inc. Nicotine transfer process
US20040112394A1 (en) * 2002-07-18 2004-06-17 Val Krukonis Reduction of constituents in tobacco
US7798151B2 (en) * 2002-07-18 2010-09-21 Us Smokeless Tobacco Co. Reduction of constituents in tobacco
US20110067715A1 (en) * 2002-07-18 2011-03-24 Us Smokeless Tobacco Co. Reduction of constituents in tobacco
US8555895B2 (en) 2002-07-18 2013-10-15 U.S. Smokeless Tobacco Company Llc Reduction of constituents in tobacco
US10045557B2 (en) 2002-07-18 2018-08-14 Us Smokeless Tobacco Co. Reduction of constituents in tobacco

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ES366409A1 (es) 1971-06-16
FR2033668A5 (fr) 1970-12-04
CH536608A (de) 1973-05-15
OA03464A (fr) 1971-03-30
IT982339B (it) 1974-10-21
NL6905868A (fr) 1970-09-22
IL32006A0 (en) 1969-06-25
ZA692659B (en) 1971-03-31
DE1915785A1 (de) 1970-12-10
BR6908558D0 (pt) 1973-02-15

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