US 2822306 A
Description (OCR text may contain errors)
United States P m- AROMATIC AND PLEASANT TASTING DE-NICO- TINIZED TOBACCO AND METHOD OF PRODUC- lNG SAME Heinz Thienemann, Beuel, and Peter Krug, Munich, Germany, assignors to Dr. Plate, G. m. b. H., Chemische Fabrik, Bonn, Germany No Drawing. Application July 1, 1955 Serial No. 519,657
22 Claims. (Cl. 131-17) The present inventionrelates to a tobacco having reduced nicotine content, and especially to such a tobacco which is aromatic and pleasant tasting as well as to a method for the production of such tobacco.
Various methods are known for the production of nicotine free tobacco or a tobacco with reduced nicotine content, in which methods the nicotine may be recovered. It is possible to use a method based either on the principle of direct solvent extraction of nicotinecompounds whereby soluble compounds will be washed out, or on the principle of leaching with an alkaline aqueoussolution which depends upon a chemical reaction to break down insoluble compounds which, after such break down, are Washed out. Methods based on each .of these principles have been modified to include steps used in methods based on the other principle. According to the variations in the method used, different amounts of nicotine will be recovered. Usually when a process basedon the principle of solvent extraction withoutany modification is used, the extraction of nicotine will not proceed to a suflicient extent whereas when substances are used which react chemically with tobacco as is true in leaching, a greater quantity of nicotine will be removed, but at the same time undesirable damage to the tobacco will occur. For this reason it has heretofore been very diflicult to obtain a good tobacco with agreeable smoking characteristics, which tobacco has reduced nicotine content. Where good smoking characteristics have heretofore been obtained, this has been at the cost of insuflicient nicotine removal.
We have found it possible to produce an aromatic and pleasant tasting tobacco with reduced nicotine content, providing that the denicotinization is carried out in the presence of a quantity of an alkalizing substance chemically corresponding in quantity to the amount of nicotine which is bound to phosphoric acid. By restricting the amount of the chemical reactant in leaching tothat quantity which has been analytically determined as that quantity necessary to treat the nicotine bound to phosphoric acid, it is possible to prevent damage of the-tobacco tozbe treated, and at he. same time. to carry the denicotinization as far as desired. a
We have found that a portion of the nicotine in tobacco is always bound to phosphoric acid, the resultingsalt or salts being insoluble in water. In research, in studying the effect of varying quantities of phosphoric acid on the process of extraction, certain principles were discovered.
With equal total nicotine content, but different content of phosphoric acid, meaning that varyingquantities of coti oc urr d nt e o of e alt of this add a greater quantity of nicotine is removed by asimple sol- 2,822,396 l atentecl Feb. 4%, 19 58:
vent reaction when less phosphoric acid is present. On
Based upon the results which we have found, denicotinization can be executed with highest yield of'nic'otine and with best care for the tobacco whenan alkaline substance is added corresponding in amount to the content of nicotine bound to phosphoric acid, the addition being made either before or simultaneously with the extraction. By this addition of a certain amount of alkaline substance, it is possible to remove from the tobacco the nicotine previously non-extractable, i. e. the nicotine bound to phosphoric acid, while, by avoiding the presence of an excess of the alkaline substance which is used, damage to the tobacco will be avoided.
The quantity of alkaline substances necessary in order to release the nicotine bound to phosphoric acid can be calculated. In doing so, it is necessary to determine first by chemical analysis :the content of phosphoric acid and total nicotinecontent in the particular lot of tobacco involved. The analytical techniques necessary for such determination are well known-and do not form part of the present invention. For example, phosphoric acid content can be determined by precipitating the phosphate with ammonium molybdate, from a solution prepared by dissolving with nitric acid an ash prepared-from a tobacco sample, the solution being diluted with water. The precipitate is then dissolved with sodium hydroxide solution, and this titrated with hydrochloric acid. In like manner, nicotine can be determined by known techniques, a precipitate first being prepared which is'soluble in water, and the aqueous solution of this precipitate being titrated with a caustic solution. From these values there is calculated the nicotine bound to phosphoric acid by means of the valences. and the secondary nicotine phosphate are possible-with the same content of phosphoric acid. Onemay obtain, therefore, two different values for bound nicotine, i. e. firstly a lower value for the primary salt, and secondly a higher value for the secondary salt. Because of the native character of the tobacco plant, there are probably formed both types of combination, and in most cases, one will find mixtures of the salts. The quantity of alkaline substances added is therefore increased or decreased depending on the nature of the phosphates present in a given tobacco.
In the case of the presence of the primary salt, the quantity of alkaline substances to be added is'smaller than in the case of the secondary salt. In the process of ex traction, an addition of alkaline substance corresponding to the primary salt will be suflicient in most cases, as
the remaining nicotine content will then be below the limit of the so-called nicotine-poor tobaccos. It is also possible to exactly determine by chemical analysis whether in an individual case more primary-or more secondary nicotine salt is present, and then to exactly calculate the necessary quantity of alkaline substance.v
ing nicotine content after a solvent extraction without Theoretically, the primary any addition of an alkaline substance, i. e. before leaching. (Nora-The values for total nicotine content, for content of phosphoric acid, and for nicotine remaining before leaching were determined by chemical analysis, while the values for amount of nicotine bound to the respective salts were calculated.)
As may be seen from these experimental results, generally with higher content of phosphoric acid relative tov the total amount of nicotine initially present, the greater is the proportionate amount of nicotine remaining after the extraction and before leaching. Furthermore, it may be seen that the amount of nicotine remaining after extraction is generally within the limits calculated for the nicotine bound in the primary and secondary salts. The values show that it is possible by determining the content of phosphoric acid, to establish the most favorable extent to which an extraction may be carried before any addition of alkaline substances. This has been impossible according to hitherto existing knowledge.
The selective nicotine extraction according to the present invention, in which a quantity of alkaline substances corresponding to the nicotine bound to phosphoric acid is addedymay be carried out with organic solvents or solvent mixtures as well as with water. For a higher yield, and a generally more careful treatment of the tobacco, it is more favourable to carry out the extraction not with the solvents or solvent mixtures alone, but in the presence of a certain amount of water. By the use of a certain quantity of water, it is possible to prevent the dehydration of the tobacco which usually occurs with the solvent extraction. By the use of water not only is embrittling of the tobacco prevented, but also the necessary opening up of the tobacco plant tissue cells is assured. Under such conditions, the solvent can enter into the cells. Furthermore, the water is a suitable carrier of the alkaline substance because this substance is in most cases more easily soluble in water than in organic solvents. The addition of water to the organic solvent or organic solvent mixture favors a selective nicotine extraction for a further reason; to wit, that a co-extraction of the waxes, resins and volatile oils will for the most part be avoided. Therefore, it is of special importance to provide a permanent saturation of the solvents or solvent mixtures respectively with water, for only then, an extensive extraction of the nicotine, together with a careful treatment of the tobacco, will be obtained, and this is indispensable for the production of smoking tobacco with reduced nicotine content. The maintenance of the saturation with water can be obtained by providing a reservoir of water, on the bottom of the solvent collecting-vessel.
ferent ways. For example, one can spread the alkaline substance on the tobacco before the extraction is carried out. One can also combine the treatment by alkaline or solvent mixtures, since a preliminary extraction as well The addition of alkaline reagents can be done in dif-- reagent with a water vapour treatment. ThlS combined: method is suitable in an extraction using organic solventmust be highly insoluble in water.
tity of alkaline substances corresponding to the content of nicotine bound to phosphoric acid to the water which is necessary for the saturation of the organic solvent. The alkaline substance may also be added to the reservoir of water on the bottom of the solvent collecting-vessel.
As alkaline substances, there are preferably used those which will not appreciably influence the pH, even at higher concentrations. They must be, however, of a higher alkalinity than the nicotine, so that a chemical release will be possible. Very much suited are ammonia, or such products which release ammonia, such as ammonium bicarbonate.
' As already mentioned, the extraction of the nicotine from the tobacco can also be carried out by leaching with water to which a quantity of alkaline substances corresponding to the content of nicotine bound to phosphoric acid has beenadded. Here again, it is possible to carry out the extraction in such a manner that the tobacco will suffer no damage, and will be entirely suited for the production of smoking tobacco. In order to give the tobacco a full flavor, it is recommended that the nicotine in the extract obtained by the leaching be removed from the extract to produce a suitable concentrate of nicotine-free extract, the denicotinized tobacco being thereafter treated with this concentrate. The process of concentration which is necessary for the manufacture of the extract is preferably carried out in vacuum, in order to avoid any damage to the ingredients therein.
The denicotinization of the extract can be carried out by means of suitable solvents, such as trichlorethylene, which may be added to the aqueous extraction product either before or after evaporation to condense such product. Simply by shaking extraction product to which solvent has been added, the latter will take up the nicotine, and the nicotine bearing solvent may then be removed from the extraction product. On the one hand, a solvent for such nicotine extraction must have a very good solubility for the nicotine, but on the other hand,
The latter requirement is important for otherwise the process of evaporation will be subject to considerable interruption and there may also be considerable loss of solvent, when the solvent for nicotine is added to the extraction product before evaporation to condense the latter.
The produced extract concentrate may be introduced to the treated tobacco either in nicotine free from, or with a certainnicotine content. Through control of the leachingo'n the one hand, and through an addition of either a nicotine free extract concentrate, or an extract concentrate with'a certain nicotine content, one can obtain a tobacco having an. entirely controlled nicotine content, i. e. one can produce either nicotine free smoking tobacco, or such tobacco having a little nicotine content.
. In order to enhance'the taste of the smoking tobacco, one can add certain arornatic substances or extracts to the concentrate obtained from the tobacco according to the present invention, which concentrate is to be introduced into the tobacco after the leaching is carried out. These aromatic substances or extracts may be of natural or synthetic origin. Furthermore, it is possible to acidity the concentrate obtained from the tobacco with such acids which are usually present in the tobacco. As accordingto the found results,'the prosphoric acid is of considerable importance, it is suitable to use it for the stated purpose. 1 'F For further improvement of the aromatic properties,-
it has proved favorable to submit the obtained denicotinized tobacco to a further aromatization in vacuum.
EXAMPLE I American Virginia tobacco having a nicotine content of 2.50% was extracted with ethyl acetate saturated with, water, with the addition of the quantity of an alkaline sub stance -correspondinga.to the content of nicotine bound to phosphoric acid. Thecontent of phosphoric 'acid-was 1.07%. This value corresponds to 1.77% bound nicotine in the form of secondary salt. Therefore, there had to be applied 1.6% ammonium bicarbonatewhich was added to the water necessary forthe saturation of the' ethyl acetate. The applied ratio of ethyl acetate to water was 5.521. The weight of ethyl acetate was fourteen times the weight of tobacco.
The extraction was carried out according to the Soxhlet method. After an extraction of 3 hours, the remaining nicotine content'was 0.58%. The tobacco so produced with reduced nicotine content was aromatized in vacuum as follows: 2% (calculated in the weight. of tobacco) of a watery-alcoholic flavor (with 30% alcohol content) was allowed to flow into an evacuatable vessel containing the tobacco, at a pressure of 25 mm. Hg. The vacuum was maintained for thirty minutes, in order to obtain an equal .distribution of the aromatic substances. By the treatment in the vacuum, the flavoring agent is more intimately combined with the tobacco, than would be the case were the agent sprayed on the tobacco, as would be done normally. The aromatized tobacco so obtained with reduced nicotine'content was cut and processed into smoking tobacco. It was extremely mild, and showed no loss of the properties of a Virginia tobacco.
EXAMPLE II American Virginia tobacco having a nicotine content of 22% and a content of phosphoric acid of 0.82% was spread with the quantity of ammonium bicarbonate (1.36%) which is necessary for the releaseof the nicotine bound in phosphoric acid, this tobacco having previously been submitted to a water vapor treatment. The extraction was carried out with ethyl acetate saturated with water according to the Soxhlet method, a reservoir of water being maintained in the solvent collecting: vessel. The remaining nicotine content was 0.39% after an extraction of 2 hours. When determining the cx tracted nicotine in the solvent, there were found 93.8% of the total quantity in the reservoir of water.
The resulting tobacco with reduced nicotine content was processed into smoking tobacco. It was found that the aroma of the original tobacco had not essentially been changed.
EXAMPLE III American Virginia tobacco having a nicotine content of 2.76% and a content of phosphoric acid of 0.93% was subjected to a water vapor treatment before the extraction was carried out; At the same time, there was applied as much ammonia as was made necessary with regard to the amount of primary nicotine salt present. For this, the water vapor producer was filled with ammonium bicarbonate. The tobacco treated in such a manner was leached with ethyl acetate according to the Soxhlet method, with maintenanceof a reservoir of water. The quantity of ethyl acetate used was tenfold the weight of tobacco used. The remaining nicotine content was 0.43% after an extraction of 4 hours.
EXAMPLE IV American Virginia tobacco having a nicotine content of 2.94% was leached with a sixfold quantity by weight of water. The leaching was carried out in two steps, at a temperature of 45 C. in the first step, and 55 C. in the second step. In the second step there was added the quantity of ammonium bicarbonate (1.69%) corresponding to the content of phosphoric acid (1.02%). The time of leaching was one hour per step. The extracts obtained in the two steps were consolidated and the nicotine removed from the extract by a threefold shaking with trichlorethylene. The remaining nicotine content in the extract was 0.2 g. per litre. The nicotine free extract was compressed to a concentrate by means of a vacuum circulation evaporator at a pressure of120 mm. Hg, the quantity of the concentrate being 28% of the original weight of'tobacco. Through an addition of citric acid the pH of the extract concentrate was adjusted to 5.8.- In -this adjustment, the extract concentrate was placed uponuthe tobacco which had'meanwhile been dried. After agstor ing of two hours, the sauced tobacco was cut,- and then roasted; h p
The so obtained tobacco with aremaining nicotinecontent of 0.53% was worked up into cigarettes. The ciga rettes were aromatic and better tastingwthan those of the untreated tobacco.
EXAMPLE V Similar'tmExarnple 4,' an'"Arnerican"Virginia tobacco having'a nicotine 'contentof' 3.26%"wasleached in two steps of one hour each'at'temperatures of 45 C. and 55 C. respectively. The. second leaching was executed with an addition of 1.5%' ofbicarbonate corresponding. tothe secondary nicotine salt bound to phosphoric acid, .under consideration of a content of phosphoric acid of 0.91%.
In contrast toExample-IV, the tobacco was subjected, however, to a water vapour treatment before being leached. Bythis, there was obtained a more favorable behavior ofthe tobacco when-placed in the leaching vessel, i. e; thebreaking was considerably reduced, and on the. other hand, the take-up of water through the cells already swelled was quicker.
From the'extract obtained through the leaching, there was produced by, evaporation under vacuum a reduction to half of thevolume ofa so-called intermediate concena trate. This was shaken three times with trichlorethylene at'a pH of 8.8 in order to remove the nicotine. The nearly'nicotine' free intermediate concentratewas further evaporated in the vacuum. The obtained 'final-concen trate corresponded to 24% of the originalweight of'tobacco. The nicotine content in the final concentrate was 10.5 g. per .kg. After an acificiation' with phosphoric acid in order to obtain a pH of 5.9, further'7.5"g. of pure nicotine were added per kg.'final concentrate, so thatafter having executed the saucing-the treated tobacco was adjusted to a nicotine content of0.6%
From the foregoing, there is to be seen thatwehave produced mild and pleasant tasting tobaccos with reduced nicotine content without any sutfering-of-the aromatic properties.
Examples of successful extractions of nicotine have been given above. There now followexamples of tures which have been used in the aromatization of "dc nicotinized tobacco. It will be noted that in'boththe mixtures given, an important ingredient is'the extract already referred to in the heretofore-described process of.
denicotinization by leaching with water to which alkaline substances have been added and where extract is specified in the following examples, it is such extract'whichis' meant. following examples, what is meant is a cleariglucose syrup obtainedfrom starch-flour by reaction with sulfuric acid. The root'tar extract specified in'thefollowingexamples is prepared by making a solution of 10 parts roottar obtained from the root of conifers with parts of 65% alcohol. This solution is distilled until 70 parts have distilled over, whereupon the distillate is then mixed with 30 parts of 65 alcohol and filtered.
EXAMPLE VI Where starch sugar syrup" is specified in the" Aromatization making use of these mixtures may be carried out by spraying them onto the dried denicotinized tobacco.
Having now particularly described and ascertained the nature of our said invention, and in what manner the same is to be performed, we declare thatzwhat we claim is:
l. A method for the production of a tobacco product from untreated tobacco containing insoluble nicotine phosphoric acid salts, comprising the steps of first quantitatively determining the content of phosphoric acid in said untreated tobacco, and subsequently treating said tobacco with a basic material capable of displacing the nicotine from the said salts, the amount of said basic material added being substantially equal to that amount required to combine in stoichiometric proportion with the phosphoric acid in said salts whereby nicotine is displaced therefrom, and the removal of nicotine so displaced from said tobacco.
2. A method as claimed in claim 1 wherein said basic material is contained in a liquid.
3. A method as claimed in claim 1 wherein the said basic material is ammonia.
4. A method as claimed in claim 1 wherein the said basic material is an ammonia derivative.
5. A method as claimed in claim 2 wherein said liquid is a non-aqueous solvent saturated with water.
6. A method as claimed in claim 5 wherein said basic material is added to the water necessary for the saturation of said non-aqueous solvent.
7. A method as claimed in claim 5 wherein a reservoir of water is maintained in the solvent vessel during removal of displaced nicotine from said tobacco.
8. A method as claimedin claim 2 wherein said liquid is ethyl acetate saturated'with water.
9. A method as claimed in claim 2 wherein said liquid is water.
10. A method as claimed in claim 1 wherein the treatment with said basic material is carried out prior to the removal of displaced nicotine from said tobacco. I
11. A method as claimed in claim 1 wherein the treatment with said basic material iscarried out simultane ously with the removal of displaced nicotine from said tobacco.
subsequent step of adding to the said tobacco product a nicotine-free extract prepared from the residue obtained upon removal of nicotinedisplaced from said tobacco.
15. A method as claimed in claim 14 wherein the residue obtained is a liquid, and said nicotine-free extract is prepared by evaporating said liquid under reduced pressure and by removing the nicotine from said liquid by adding to said-liquid a reagent in which the nicotine is soluble, but which reagent is substantially insoluble in water, and thereafter removing said reagent after said nicotine has dissolved therein.
16. A method as claimed in claim 1 including the subsequent step of adding to the said tobacco product an extract prepared from the residue obtained upon removal of nicotine displaced from said tobacco, a portion of the nicotine being removed from said residue.
17. A method as claimed in claim 14 in which phosphoric acid is added to said extract prior to the addition thereof to the said tobacco product.
18. A method as claimed in claim 14 in which aromatic substances are addedto said extract prior to the addition thereof to the said tobacco product.
19. A tobacco'product prepared from untreated tobacco containing insoluble nicotine phosphoric acid salts, from which untreated tobacco nicotine has been removed by use of an amount of basic material sufficient only to combine in stoichiometric proportion with the phosphoric acid in the said nicotine phosphoric acid salts.
20. A tobacco product prepared from untreated tobacco containing ins-olublenicotine phosphoric acid salts, from which untreated tobacco nicotine has been extracted by use of a solution of water containing an amount of basic material sufiicient only to combinein stoichiometric proportion with the phosphoric acid in the said nicotine phosphoric acid salts.
21. A tobacco product as claimed in claim 20 to which has been added an extract concentrate prepared from said solution after the removal of said solution from said tobacco product, a portion of the nicotine having first been removed from said solution.
22. A tobacco product as claimed in claim 19 which has been rendered aromatic by the addition of aromatic substances.
References Cited in the file of this patent UNITED STATES PATENTS 246,975 Philips Sept. 13, 1881 802,487 Wimmer Oct. 24, 1905 999,674 Sartig Aug. 1, 1911 1,577,768 Smith Mar. 23, 1926