Description:
This invention relates to new smoking products and a method for preparing them.
As used herein, the term "smoking products" is meant to refer to and to include filler material embodied in cigarettes, cigars and for use with pipes and the like, and mixtures thereof with various proportions of tobacco and including cigarette papers and wrappers used in the preparation of such cigars and cigarettes, and it includes cigarettes, cigars and the like products manufactured with such filler materials and wrappers.
In the aforementioned applications, description is made of the preparation of a smoking product suitable for use in cigarettes, cigars or with pipes wherein the smoking product is prepared of relatively pure cellulosic materials subjected to selective oxidation with liquid nitrogen dioxide to convert preferably more than 90 percent of the methylol groups in the cellulosic molecule to yield a product which can be referred to as an oxycellulose or polyuronic acid. The oxidation reaction product is further processed by removal of liquid nitrogen dioxide by vaporization and preferably by washing the oxidized cellulosic product with water and/or alcohol and/or acetone or other solvent for removal of solubilized foreign material, including oils, waxes, latices and the like, which contribute undesirably to the taste and aroma when used as a smoking product in accordance with the practice of this invention.
One method for effecting this oxidation is disclosed in copending application, Ser. No. 745,221, filed July 16, 1968, now U.S. Pat. No. 3,516,416, wherein description is made of the oxidation of a cellulosic material by suspension in liquid nitrogen dioxide in the ratio of one part by weight cellulosic material to 5 to 1,000 parts by weight liquid nitrogen dioxide, and preferably one part by weight cellulosic material to 25 to 50 parts by weight of the liquid nitrogen dioxide. The reaction therein is carried out at a temperature within the range of 15° to 65° C., and at autogenous pressure when the reaction temperature exceeds 21° C., the boiling point of nitrogen dioxide.
Another method for effecting this oxidation is disclosed in copending application Ser. No. 745,135, entitled "Preparation of Smoking Products of Cellulose Derivatives and Process," filed July 16, 1968, now U.S. Pat. No. 3,491,766, wherein the oxidation reaction, including reaction rate and amount of conversion, is materially improved by formulation of the oxidation reaction mixture to contain up to 8 percent by weight of water in the liquid-nitrogen-dioxide system and by carrying out the reaction at elevated temperatures above 15° C., and preferably between the range of 20° to 45° C., depending somewhat upon the amount of moisture present in the reaction medium, whereby the reaction medium is rendered relatively nonelectrically conductive so that the presence of water in the reaction medium will not result in attack or degradation of the cellulosic material to be oxidized, and wherein the formulation to include aqueous medium in the reaction of liquid nitrogen dioxide also operates to adjust the specific gravity of the reaction mixture in the direction towards the specific gravity of the cellulosic material whereby suspension of the cellulosic material in the reaction medium is easier to achieve and maintain. The result is a more rapid and uniform oxidation reaction of the cellulosic material to produce a better product at a more rapid rate.
A further method for effecting the oxidation of cellulosic materials is disclosed in copending application, Ser. No. 774,064, filed Nov. 7, 1968, and entitled "Method for Producing Smoking Product of Oxidized Cellulosic Material" wherein the cellulosic material is first wetted with liquid nitrogen dioxide and then is exposed to hot gaseous nitrogen dioxide and then is exposed to hot gaseous nitrogen dioxide. This particular method can be advantageously used in the form of a continuous process for the production of large quantities of oxidized cellulosic materials.
The resulting smoking product is then formulated with mineralizing agents such as oxalates, glycolates, diglycolates, lactates, pivalates or tannates of such metals as calcium, magnesium, lithium, potassium, barium, strontium, preferably introduced to form the salt internally in the cellulosic derivative for purposes of providing desired ashing characteristics. Instead of forming the described salts internally in the cellulosic derivative, limited beneficial characteristics can be achieved by external application of such mineralizing agents. As described, the desired internal introduction is achieved by first wetting the cellulosic derivative with metal cation in dilute solution for absorption into the cellulosic derivative followed by exposure to the acid anion in solution to precipitate the metal salt in situ in the cellulosic material.
This application is addressed to a process of treating oxidized cellulosic material, independent of the method by which the cellulosic material is oxidized, with an agent which enhances the odor and aroma which accompanies the burning cellulosic material.
It is an object of this invention to produce and to provide a method for producing a cellulosic material which is suitable for use in smoking and which finds wide acceptance as a smoking product from the standpoint of taste, aroma, appearance, burning characteristics and relative absence of undesirable reaction products.
As the cellulosic raw material, use can be made of various forms of cellulose, such as wood pulp, straw, alpha-cellulose, flax, fibrous carbohydrates, seaweed carbohydrates, bamboo filaments, cotton filaments, hemp, refined paper, rice paper, filamentous gums and even plants and plant leaves and the like fibrous materials from which noncarbohydrate components have been separated, all of which is hereinafter referred to as cellulosic material.
It is preferred to make use of a purified cellulosic material from which various of the sugars, proteins, chlorophylls, flavones, colors, lignins, oils, waxes, resins and lactices have been removed since these contribute undesirable odors and tastes to the smoking product.
Purified cellulose is unsatisfactory for use as a smoking product from the standpoint of taste, aroma and burning characteristics. This is believed to stem from the acids and aldehydes that are evolved upon pyrolysis of the cellulose. It has been found that many of the defects of pure cellulose can be greatly alleviated by conversion of the methylol groups to carboxyl groups to produce a product which readily pyrolyzes with complete breakup of the cellulosic molecule into water vapor, and oxidation products of carbon such as carbon dioxide and low molecular weight compounds which readily volatilize off. However, residual odors persist in spite of the advantages gained through oxidation of cellulosic materials.
It has been found that undesirable residual odors can virtually be eliminated and the taste of the cellulosic material vastly improved by treating oxidized cellulosic material with an aldehydic or alcoholic agent. It is believed that the compounds utilized in accordance with the present invention become incorporated with the cellulosic material, and are preferentially sought out by the olfactory senses, thereby to dominate over any undesirable odors from the burning cellulosic material.
In referring to the "incorporation" or "association" of the aldehydes or alcohols with the material being treated, it will be understood that no specific limitation is intended. Diffusion within the fibers of the material treated has been recognized while presence of the materials in particulate form on the exterior of the fibers is also contemplated.
It has been found that aromatic compounds of the formula:
wherein X is alkylene or methyl-substituted alkylene having one to six carbon atoms; Z is --CHO or --CH 2 OH and, Y is a substituent selected from the group consisting of hydrogen, hydroxy, alkyl, such as methyl, ethyl, propyl, t-butyl, etc., having from one to six carbon atoms, and alkoxy, such as methoxy, ethoxy, butoxy, etc., having one to six carbon atoms, are suitable to enhance odor and aroma. Representative compounds falling within this definition include α-methyl-β (par-tert-butyl phenyl) propionaldehyde, which is available commercially under the trademark "Lilial" from Givaudan-Delawanna, Inc. of New York; phenyl propyl aldehyde; and phenyl ethanol.
Another group of compounds which can be used as treating agents in the present invention is the C 9 to C 18 long chain fatty aldehydes, having either branched or straight chains. Representative of this group is nonyl aldehyde (C 9 ), capryl aldehyde (C 10 ), undecylenyl aldehyde (C 11 ) and lauryl aldehyde (C 12 ). It is important that the fatty acid aldehyde contain at least nine carbon atoms since the corresponding C 5 through C 8 aldehydes gave a strong burning odor upon pyrolysis, and are therefore apparently unsuitable.
Various hydroxy compounds have also been found to be suitable as treating agents in the present invention. Such compounds include 3, 7-dimethyl-2, 6-octadienol, more commonly known as geraniol. Also suitable are methyl heptyne carbonate, ethyl glyoxalate, sandalwood oil and amyris oil. East Indies sandalwood oil is available commercially, and may be derived by distillation of Santalum album of India. Australian sandalwood oil is similarly commercially available and is derived by distillation of wood of Eucarya spicata in Western Australia.
The agents of the present invention may be incorporated with the oxidized cellulose by any of a wide variety of procedures. For example, it is possible to soak the oxycellulose in a dilute solution of the agent in water, alcohol or a mixture thereof. Any inert solvent may be used. It is preferred to incorporate the agent in the cellulose by spraying a dilute solution of the agent in an inert solvent onto the cellulose.
The amount of agent applied is not critical, and it is generally sufficient to apply an amount such that any unpleasant odors of the pyrolyzing cellulose are not detectable. An amount within the range of 0.01 to 0.05 percent by weight of the cellulose is usually sufficient for this purpose.
After treatment with the odor mask, the resulting oxidized cellulose may be, if desired, washed to remove excess agent.
The odor of burning protein or paper is not noticeable during pyrolysis of the cellulosic material treated in accordance with the concepts of this invention. It has been found that of the foregoing agents, sandalwood, amyris oil, geraniol, phenyl ethanol, alpha-methyl-beta-(para-tertiary-butyl phenyl) propionaldehyde and methyl heptyne carbonate are the most effective.
The odor evolved by the agent is not necessarily the same as that which is characteristic of the particular agent material. On the contrary, the odor produced is that which is characteristic of the particular agent during rapid pyrolysis with the oxidized cellulose. For this reason, agents should be selected upon the basis of the odors evolved upon pyrolysis, with the oxidized cellulose, and not upon the characteristic odor of the agent per se.
The following examples illustrate a typical process for the preparation of a smokable material in accordance with the present invention.
EXAMPLE I
A highly purified commercial grade of wood pulp is fabricated into a thin paper of a thickness comparable to a commercial cigarette paper. This paper is shredded into strands of about 2 mm. width and immersed in approximately 100 times its weight in liquid nitrogen dioxide maintained at 20° C. Immersion is continued for about 5 to 10 days, or until testing indicates a carboxyl level of 92- 100 percent, expressed as polyanhydroglucuronic acid content. The testing involves washing in aqueous alcohol, drying, dissolving in excess standard alkali, and then back titrating with standard acid.
The shredded material is then substantially freed of excess NO 2 by means of a warm stream of dry air. A solution of 0.03 percent by weight of phenyl propyl aldehyde is sprayed upon the shredded material, and the alcohol is allowed to evaporate. Analysis showed that the cellulose contained 0.037 percent by weight of phenyl propyl aldehyde.
The shredded cellulose is wrapped in the form of a cigarette in cigarette paper which had been treated in the same manner with phenyl propyl aldehyde. It has been found that the residual odor can best be tested in a "drum" test, which is conducted in the following manner. A one-fourth inch of the above described cigarette is burned in a closed top drum. To avoid irritant affects, an interval of 3 minutes is allowed to elapse, and the odor in the drum is tested through an opening in the top.
The drum test reveals no burnt paper odor, but yields a pleasant fernlike odor.
When the drum test is repeated on the shredded cellulose used above, but not treated with phenyl propyl aldehyde, an acrid odor characteristic of burning paper is detected. Residual caramel odors are likewise detected.
EXAMPLE II
The shreaded cellulose produced in Example I is sprayed with a 0.4 percent alcoholic solution of "Lilial," which was substantially pure α-methyl-β (para-tert-butyl phenyl) propionaldehyde. Analysis showed that the "Lilial" content was 0.015 percent by weight.
Drum tests on cigarettes made from the treated cellulose reveal no unpleasant odor. The odor detected had a pleasant floral sent.
EXAMPLE III
Oxidized cellulose in the form of shredded strands produced in the same manner as in Example I is sprayed with a dilute solution of lauryl aldehyde in alcohol until the cellulose contained 0.02 percent by weight of the aldehyde.
Drum tests showed the absence of any unpleasant odors as only a mild soap odor was detected.
EXAMPLES IV-IX
Shredded cellulose produced in the manner shown in Example I is treated with C 9 to C 11 , C 14 , C 16 and C 18 fatty aldehydes. Drum tests conducted on each sample revealed the following:
C 9 laundry soap odor C 10 coconut odor C 11 soap odor C 14 nut odor (peach kernel) C 18 scorched nut odor
The materials prepared in accordance with the practice of this invention find excellent use as a smoking product in cigarettes, pipes and like smoking devices. Use can be made of the treated material alone or in admixture, in various proportions with tobacco. A cigarette can be made by cylindrically wrapping the shredded material with cigarette paper, or preferably with paper treated in accordance with the instant invention, or better still with a paper made with pulp thus treated. A cigarette filter can then be attached, such a filter being treated with an appropriate flavor such as methol. Individuals smoking the individual type product will experience a clean taste, and the smoke inhaled will prove to be extremely mild, and in no sense irritating.
It will be understood that various changes and modifications may be made in the above described products and processes which provide the characteristics of the invention without departing from the spirit thereof particularly as defined in the following claims.