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United States Patent: 4,257,430 Page 11 of 16 A series of experiments was undertaken to evaluate the effect of temperature on the rate of formation of insoluble palladium in a casing formulation containing: Component Weight Percent Invert Sugar 15.4 Flavor 4.4 Propylene glycol 2,2- Glycerine 6.5 Corn Syrup 4.9 Lactic Acid 0.5 (NH.sub.4).sub.2 PdCi.sub.6 1.2 Mg(NO.sub.3).sub.2 . 6H.sub.2 0 Water 33 2 100.0 Three separate mixtures were prepared, held at 23.degree. C., 60.degree. C. or 70.degree. C., and periodically analyzed to determine soluble palladium. The insoluble palladium formed after one hour was determined, and is used as a measure of the rate of the first stage reaction. In addition, the first order rate constant, k was calculated from a plot of the logarithm of soluble palladium against time. The data are summarized as follows: Insoluble Palladium Formed in 1 Hr., as % Rate Constant, Temperature, .degree.C. of Total Palladium k, hr..sup.-1 23 0 0.00 60 36 0.03 70 41 0.19 0 0 w co - ~- a rn EXAMPLE 3 Employing procedures and materials similar to those described in Example 2, except 0 http://164.195.100.11/netacgi/nph-Parser?Sect1=PTO1&Sect2=HIT.../425743 2/13/01

United States Patent: 4,257,430 EXAMPLE 1 Page 10 of 16 A casing formulation was prepared in accordance with the following table: Component Invert Sugar Glycerine Corn Syrup Flavor Gum Tragacanth Mg(NO.sub.3).sub.2 5% Aq*(NH.sub.4 2 (pH = 1.5) Water *Aqueous Weight Percent 23.56 3.84 6.12 3.87 0.25 6H.sub.2 0 34.30 Pd(Cl.sub.4) 10.30 17.76 100.00 The resulting solution was heated at 77.degree. C. and the solution was periodically analyzed for soluble palladium and total palladium. The results of these analyses are summarized as follows: Time, hr. Palladium Present in Casing as % of Total Palladium Soluble Insoluble 1 27.5 72.5 2 15 85 3 10 90 4 7 93 5 3 97 20 1 99 The formation of insoluble palladium was found to occur in two stages: the first, by a rapid reaction which is essentially complete in about 1 hour, and the second by a slower reaction which appears to obey first order kinetics. EXAMPLE 2 http://164.195.100.11/netacg'i/nph-Parser?Sect1=PTO1 &Sect2=HIT.../425743 2/13/01

United States Patent: 4,257,430 Page 16 of 16 *Added as Mg(NO.sub.3).sub.2 . 6H.sub.2 O **Extrapolated from data curve from 74 week results to 80 weeks As is evident from the foregoing, the yield of polycyclic aromatic hydrocarbons and the incidence of tumors in mice both decrease as the amount of non-extractable palladium increases. In general, substantial reductions in the incidence of tumors are achieved when the amount of total nitrate is in excess of about 0.4 weight percent and the amount of non-extractable palladium is greater than about 100 ppm. It is preferred, however, that there be employed at least about 0.7 weight percent total nitrate nitrogen and at least about 250 ppm of non-extractable palladium. Most preferably, there should be employed at least about 0.7 weight percent total nitrogen and at least about 450 ppm of non-extractable palladium. Images Home View Shopplng Cart Boolean Add to Shopping Cart 1 Humber Help http://164.195.100.11/netacg'i/nph-Parser?Sect1=PTO1 &Sect2=HIT.../425743 2/13/01

United States Patent: 4,257,430 Page 15 of 16 purposes of evaluating the effect of changes in nitrate and palladium content, and the amount of non-extractable palladium on biological activity, the individual values for percent tumor incidence and yield of PCAH were averaged. % of Sample Yield of PCAH Tumor Incidence A-1 2.258 42.0 B-1 2.329 47.9 C-1 2.245 41.9 D-1 2.148 55.3 Average 2.245 46.8 For each experimental run, the ratios of the observed yield of PCAH and tumor incidence to the average of the control values were calculated. The results are summarized in Table III. TABLE III PCAH Yields and Tumor Incidence of Test Samples Compared With Controls Biological Response Total Nit. Added Nit. ppm Pd PCAH Yield as % of Sample Nitrogen % Nitrogen %* Total Non-Ext As % of Ave. Con. Avg Control A-2 0.22 -- 470 300 92.3 84.6 C-2 0.55 -- 0 -- 88.4 88.2 B-2 0.47 -- 580 80 69.1 69.7 B-3 0.59 -- 580 140 68.5 (56)** D-4 0.80 -- 820 210 56.0 53.4 D-3* 0.69 -- 660 180 63.2 46.4 C-3 0.75 0.47 0 -- 84.4 57.9 D-2 0.77 0.46 550 160 56.7 36.3 C-4 0.73 0.44 440 260 68.5 17.7 A-3 0.74 0.44 550 360 62.9 4.9 http://164.195.100.11/netacgi/nph-Parser?Sect1=PTO1&Sect2=HIT.../425743 2/13/01

llnited States Patent: 4,257,430 Page 1 of 16 US PATENT & TRADEMARK OFFICE PA"1"I~N`?' FULL `7]~X"[" AND llh+AGIE4 ~`1..Fi"'E"AMASZ 1Te+,vSl-iapPirig U'art (_1,of1) United States Patent 4,257,430 Collins, et at. March 24, 1981 Tobacco composition including palladium Abstract Improved palladium-containing smoking tobacco compositions wherein the palladium in a highly active form is obtained by depositing on the tobacco palladium which has been insolubilized by admixing in an aqueous medium a water-soluble palladium compound and a reducing agent capable of reducing dissolved palladium cations to insoluble palladium. Methods for determining the amount of insoluble or active palladium are described. Inventors: Collins; Peter F. (Durham, NC); Bryant, Jr.; Herman G. (Durham, NC); Pullman; James O. (Chapel Hill, NC) Assignee: Liggett Group Inc. (Montvale, NJ) Appl. No.: 013575 Filed: February 21, 1979 Current U.S. Class: 131f300; 131/309; 131/352 Intern'l Class: A24B 015/28; A24B 015/42 Field of Search: . 131/t40 B,17 R,2,15 R,140 R Referenc,es Cited.Referenged Byj N ° - Patent Documents U S o o ~ _ . . . 4055191 Oct., 1977 Norman et al. 131/9. rn cc ~ Primary Examiner: Millin; Vincent Attorney, Agent or Firm: Ross, Jr.; J. Bowen cn~ W_ Claims http://164.195.100.11/netacgi/nph-Parser?Sect1=PTO1&Sect2=HIT.../425743 2/13/01

United States Patent: 4,257,430 Page 14 of 16 Series Sample Native Total Total Non-Extractable A 1* 0.22 0.22 0 -- 2* 0.22 0.22 470 300 3* 0.30 0.74 550 360 B 1 0.22 0.22 0 -- 2 0.47 0.47 580 80 3 0.59 0.59 580 140 C 1 0.17 0.17 0 -- 2 0.55 0.55 0 -- 3 0.28 0.75 0 -- 4 0.29 0.73 440 260 D 1 0.23 0.23 0 -- 2 0.31 0.77 550 160 3** 0.69 0.69 660 180 4 0.80 0.80 820 210 *These samples are the controls and Samples A and B employed in "Biological Test" of U.S. Pat. No. 4,055,191. **0.42 weight % Mg.sup.++ added as a 1/1 mixture of magnesium ma magnesium acetate to the tobacco TABLE II eummary of Evaluation of Tobacco Smoke and Condensate Active PCAH Yield, f A i l % Series Sam o n ma s ple mg per gram of dry smoke with Tumors A 1 2.258 42.0 2 2.073 39.6 3 1.412 2.3 B 1 2.329 47.9 2 1.551 32.6 3 1.538 43.8(22.5)* C 1 2.245 41.9 2 1.948 41.3 3 1.895 27.1 4 1.537 8.3 D 1 2 148 55 3 PJ . . 0 2 1 272 17 0 00 . . -1 . 3 1.419 21.7 CF) 4 1 258 25 0 to: . . da A *In this experiment, there was a sudden anomolous increase in th O) '' CO ^ of tumor bearing mice following the 74th week. The value in pare estimated from the tumor incidence observed through the 74th wee In the four series of tests, Samples A-1, B-1, C-1 and D-1 served as controls. For http://164.195.100.11/netacgi/nph-Parser?Sect1=PTO1&Sect2=HIT.../425743 2/13/01

United States Patent: 4,257,430 Page 3 of 16 This invention relates to smoking compositions comprising tobacco having associated therewith palladium as a catalytic agent. More particularly, the present invention is concerned with tobacco compositions including palladium as a catalytic agent wherein the palladium is in a highly active form. This invention is also concerned with a method for admixing smoking tobacco and palladium whereby the palladium is deposited in a highly active catalytic form. RELATED APPLICATIONS AND PATENTS The subject matter of this invention is related to the subject matter of U.S. Pat. No. 4,055,191, granted Oct. 25, 1977 to V. Norman and H. G. Bryant, Jr. for "Tobacco Composition", and (Ser. No. 344,589 filed Mar. 26, 1973 by H. G. Bryant, Jr., T. B. Williams and V. Norman for "Smoking Composition"). BACKGROUND As is summarized in U.S. Pat. No. 4,055,191, the proportion of polycyclic aromatic hydrocarbons (PCAH) in the smoke from tobacco can be materially reduced by incorporating palladium into the tobacco. It is further disclosed that palladium in combination with a nitrate salt, preferably magnesium nitrate, is even more efficient in reducing PCAH. Moreover, the combination of palladium and nitrate was shown in tests on mice to materially reduce the biological activity of tobacco smoke condensate obtained by smoking cigarettes on a wheel-type smoker as described in DESCRIPTION OF THE INVENTION In work undertaken to evaluate the effect of palladium and nitrate on the biological activity of tobacco smoke, certain anomalous results were observed. Subsequent evaluation of the data obtained in the course of this work indicated that the activity of the palladium depended on the form of the palladium which was deposited on the tobacco, which in turn was highly dependent upon the procedure employed. More particularly, it has been found in accordance with this invention that the effectiveness of palladium in reducing the biological activity of tobacco smoke is dependent on the amount of "non-extractable palladium", as hereinafter defined, which is deposited on the tobacco. The amount of "non-extractable palladium", in turn, is dependent on the deposition of the palladium from an aqueous composition including "insoluble palladium", as hereinafter defined. Accordingly, it is an object of this invention to provide a smoking tobacco including palladium in a highly active form. It is another object of this invention to provide palladium-treated smoking articles http:// 164.195.100.11/netacgi/nph-Parser?Sect1=PTO1 &Sect2=HIT.../425743 2/ 13/01

United States Patent: 4,257,430 What is claimed is: Page 2 of 16 1. A method for the deposition of catalytically active metallic palladium on smoking tobacco comprising: (a) Forming an aqueous solution containing a soluble palladium compound, and a compound capable of reducing ionic palladium cations to palladium metal, said solution having a pH of no more than 3; (b) Heating said solution at an elevated temperature for a period of time sufficient to convert at least about 50 percent of the palladium to insoluble palladium; and (c) Admixing the casing solution with tobacco to deposit thereon said insoluble palladium. 2. A method according to claim 1 wherein said reducing agent is a hydroxyl containing aldehyde. 3. A method according to claim 2 wherein said reducing agent is a sugar. 4. A method according to claim 1 wherein said aqueous solution containing palladium is a casing solution including at least one sugar and at least one polyhydroxy compound. 5. A method according to claim 4 wherein said soluble palladium compound is selected from the group consisting of palladium nitrate, palladium chloride, palladous dichlorodiamine, ammonium tetrachloropalladate and ammonium hexachloropalladate. 6. A method according to claim 5 wherein said palladium salt is ammonium tetrachloropalladate. 7. A method according to claim 1 wherein said heating is at a temperature of from about 50.degree. C. to about 90.degree. C. 8. A method according to claim 4 wherein said heating is at a temperature of from about 50.degree. C. to about 90.degree. C. for a period of time sufficient to convert at least 95 percent of soluble palladium to insoluble palladium. _ _ .......... ._........... - --- - -- -------- Description_ http://164.195.100.11/netacgi/nph-Parser?Sect1=PTO1&Sect2=HIT.../425743 2/13/01

United States Patent: 4,257,430 Page 13 of 16 EXAMPLE 5 Several casing solutions containing various amounts of soluble palladium were prepared and employed to treat tobacco samples which then were analyzed for extractable palladium. The data for these runs is summarized as follows: % of Total Palladium Sample Soluble Pd in Casing Extractable Pd in Tobacco 1 74.7 87.1 2 67.0 80.4 3 61.4 68.3 4 46.9 63.3 5 32.8 49.7 6 25.8 42.7 As is evident from the foregoing, the proportion of extractable palladium in the tobacco is proportional to, but greater than, the proportion of soluble palladium in the casing solution. Consequently, even if the amount of soluble palladium in the casing is reduced to zero, the resulting tobacco will nonetheless contain extractable palladium, perhaps amounting to 10 percent or less of the total palladium. EXAMPLE 6 Employing procedures similar to those described in the Biological Test described in U.S. Pat. No. 4,055,191, cigarette tobacco was treated with casings including palladium. The tobaccos employed had varying natural nitrate contents, and in some instances the casings also contained added magnesium nitrate. The tobacco samples were then employed to prepare sample cigarettes which then were smoked on the wheel-type smoker to collect smoke condensate used for mouse-painting tests. For each tobacco sample, the incidence of tumor-bearing mice, as a percentage of the total mice at risk, was determined after 80 weeks. In addition, the nitrate content (native nitrate and added nitrate) and the palladium content (total and non-extractable) was determined. Finally, the yield of polycyclic aromatic hydrocarbons in the dry smoke was determined. The data are summarized in Tables I and II. ~ ~. TABLE I O) Summary of Content of Tobacco Samples V Nitrate Content, % Palladium Content, ppm http://164.195.100.11/netacgi/nph-Parser?Sect1=PTO1&Sect2=HIT.../425743 2/13/01

United States Patent: 4,257,430 Page 9 of 16 hydrochloric acid is added, the cover is replaced and the mixture is heated to boiling. Then 10 ml of water are added to the residue and the mixture is digested by heating near boiling (80.degree.-100.degree. C.) for 10 minutes. The solution is then cooled to room temperature and diluted to 25 ml with water to form a sample to be subjected to analysis for palladium. II. Analysis for Insoluble Palladium in Casing The insoluble palladium in the casing is that palladium in casing which is not soluble in water, and is determined by subtracting soluble palladium from total palladium. Total and soluble palladium are determined by the following procedures: Determination of "Total Palladium" In Casing An accurately weighed sample of about 0.3 gm of well mixed casing is placed in a 100-m1 beaker, and 5 to 10 ml of 1:1 nitric acid and perchloric acid is added. The resulting mixture is then worked up following the procedures described for determining total palladium in tobacco. Determination of "Soluble Palladium" In Casing A 0.3 to 3.0 ml portion of casing is accurately weighed in a 10 ml volumetric flask, and is diluted to 10 ml with water. The resulting solution is thoroughly mixed and is immediately filtered through a membrane filter having a pore size of not greater than 0.45 microns. A 2 to 5 aliquot of filtrate is mixed with 5 to 10 ml of 1:1 nitric acid and perchloric acid, and the resulting solution is treated as described above to achieve a sample for analysis for "soluble palladium". In carrying out this procedure, it is desirable to select sample and aliquot sizes so that there will be at least 15 micrograms, and preferably 50 to 200 micrograms, of palladium in the sample for analysis. III. Palladium Analysis Any procedure capable of accurately determining the quantity of palladium in the thus-obtained samples of "Total", "Extractable" and "Soluble" palladium may be employed. When analyzing for total palladium, atomic absorption spectroscopy has been found sufficient. When analyzing for "Extractable" or "Soluble" palladium, however, a more sensitive procedure is desirable. It has been found that the procedure of O. Menis and T. C. Rains, "Colorimetric Determination of Palladium With Alpha- Furildioxime," Anal. Chem., 27, 1932-34 (1955), is suitable for this purpose. In the examples which follow, "Extractable" or "Soluble" palladium was determined by adapting the Menis et al. procedure to automatic analysis with a Technicon Auto- Analyzer I. http:// 164.195.100.11/netacgi/nph-Parser?Sect 1=PTO 1&Sect2=HIT.../425743 2/ 13/01