WO2008056011A1

WO2008056011A1 - Tobacco/catalyst mixtures for reducing toxic compounds in tobacco smoke

Info

Publication number: WO2008056011A1
Application number: PCT/ES2007/000628
Authority: WO
Inventors: Antonio Marcilla Gomis; María Isabel BELTRAN RICO; Amparo Gomez Siurana; Rosa Navarro Martinez; Deseada BERENGUER MUÑOZ; Isabel Martinez Castellanos
Original assignee: Universidad De Alicante
Priority date: 2006-11-07
Filing date: 2007-11-05
Publication date: 2008-05-15
Also published as: ES2301392B1; EP2092838A1; EP2092838B1; DK2092838T3; ATE547015T1; EP2092838A4; ES2383359T3; ES2301392A1

Abstract

The invention relates to the use of certain additives which are mixed with tobacco in order to reduce the quantity of toxic and carcinogenic substances found in tobacco smoke. The invention also relates to tobacco/additive compositions and to the preparation method thereof.

Description

TOBACCO-CATALYST BLENDS FOR REDUCTION OF TOXIC COMPOUNDS PRESENT IN TOBACCO SMOKE

The present invention is framed in the field of the smoking articles preparation industry. More specifically, the present invention relates to the use of tobacco-catalyst mixtures for the reduction of toxic compounds present in tobacco smoke.

STATE OF THE PREVIOUS TECHNIQUE

In today's society, the habit of smoking tobacco represents a global problem with very negative consequences on the health of human beings, with a very significant impact on public health departments or ministries. The smoke that is generated in the combustion of tobacco contains a series of toxic and carcinogenic compounds that are inhaled by smokers, both active and passive, and that make tobacco a major cause of death worldwide.

In tobacco and smoke generated by combustion, more than 4000 different compounds have been identified [RR Baker and LJ. Bishop, J. Anal. Appl. Pyrol., 74 (2005), 145], of which at least 60 are recognized as toxic and carcinogenic. Among these compounds are tars, carbon monoxide and dioxide, acetaldehyde, phenols, acetone, formaldehyde, benzene, toluene and nicotine. Nicotine is the main addictive component present in tobacco and, in the human body, it is transformed into a metabolite called cotinine, which, since it has been found only in smokers and passive smokers, is used as a benchmark for measure the degree of exposure to tobacco smoke. The process of smoking a cigarette generates the appearance of two types of smoke currents, the so-called "mainstream", consisting of the smoke that the smoker inhales and exhales directly from the cigarette; and the secondary current consisting of the smoke that is eliminated through the lit cigarette, which is diluted in the surrounding air and inhaled by passive smokers. The main current corresponds to the smoke that is generated in the combustion of tobacco and passes through the cigarette from the lit end, to exit through the end of the filter. Since this is the current As smokers inhale, it is of great interest to eliminate or reduce its content in toxic substances.

Different methods and additives have been proposed in order to reduce the toxicity of tobacco smoke. In most of these, materials other than zeolites or aluminosilicates are used. One of the first proposals corresponds to Seeofer et al. [Seeofer, F., kausch, E., "Removal of nitric oxide and carbon monoxide from tobáceo smoke", US 4,182,348, jan 8, 1980], which use a compound of formula M ₂ M ¹ RuOe, where M is a metal divalent, M 'is a lanthanoid or actinoid trivalent metal, Ru acts with valence 5, and M and M' can form a perovskite layer with Ru ions. This compound, once mixed with tobacco or incorporated into the paper or filter, contributes to the elimination of NO and CO from tobacco smoke. In the same vein, Rongved [Rongved, P., "Catalytic cigarette smoke cleaning devise and process", US 5,671, 758A, Sept 30, 1997] also describes a type of filler that reduces toxic substances, such as CO, from the combustion gases of tobacco, by the addition of solid, inert, stable and non-polluting catalysts, together with or near tobacco. Among these catalysts, it proposes the use of vanadium pentoxide, molybdenum trioxide and radio oxides. Among the first patents is also Rosen's [Rosen,

WE, "Method of treating tobáceo", US 3,840,026, Oct 8, 1974], in which the use of an absorbent material is proposed, with a high moisture content, and in a proportion comprised between 1 and 50%, to reduce undesirable products generated in the combustion of tobacco. The type of material belongs to the land group of infusoria, diatoms and calcium or magnesium silicates.

More recently, Li et al. [Li, P., Hajaligol, M., "Oxidant / catalyst nanoparticles to reduce carbon monoxide in the mainstream smoke of a cigarette", US 20030075193, April 24, 2003] have described the use of Fe ₂ θ3, CuO, TiO nanoparticles ₂ , CeO ₂ , Ce ₂ O ₃ , AI ₂ O ₃ , and ₂ O ₃ doped with Zr, Mn ₂ O ₃ doped with Pb, as well as mixtures of these materials, to increase the degree of conversion of CO to CO ₂ . This patent also describes the procedure for the preparation of cigarettes, which includes a) the addition of the nanoparticle additive to the tobacco bite, b) the introduction of the most additive tobacco bite mixture into a machine manufacture of cigarettes to form a cigarette and c) the placement of the paper wrap around tobacco to shape the final cigarette. In a continuation of this patent [Li, P., Hajaligol, M., "Oxidant / catalyst nanoparticles to reduce tobáceo smoke constituents such as carbon monoxide", US 200313118759, July 17, 2003], the same authors show the capacity of the Additives described to reduce the amount generated from other constituents of tobacco such as aldehydes, 1,3-butadiene, soprene, acrolein, acrylonitrile, HCN, o-toluidine, 2-naphthylamine, nitrogen oxides, benzene, N-nitrosonornicotine , phenol, catechol or benzantracene). In another patent, Li et al. [Li, P., Rasouli, F., Hajaligol, M., "Manganese oxide mixtures in nanoparticle form to lower the amount of carbon monoxide and / or nitric oxide in the mainstream smoke of a cigarette", US 6,782,892, August 31, 2004 ] have shown that coprecipitation of manganese oxide with any of the previously studied nanoparticles also contributes to increasing the degree of conversion of nitric oxide to nitrogen. In the same line as the previous patents, Li et al. [Li, P., Rasouli, F., Hajaligol, M., "Catalysts to reduce carbon monoxide and nitric oxide from the mainstream smoke of cigarette", WO 2004/110184, December 23, 2004] also describe an additive consisting of a catalyst containing nanoparticles of a metal and / or a metal oxide supported on a fibrous material, which increases the conversion of carbon monoxide into carbon dioxide and nitric oxide into nitrogen, while in a different patent [Rasouli, F., Li , P., Zhang, W.-J, Gedevanishvili, S., "Use of oxyhydroxide compounds in cigarette paper for reducing carbon monoxide in the mainstream smoke of a cigarette", WO 2005/039326, May 6, 2005], the use, with the same purpose, of additives based on hydroperoxides of transition metals or rare earths or mecías of these materials. All these patents also describe the role and methods used for the preparation of cigarettes, as well as the conditions in which they were smoked.

In 2004, Li et al. [Li, P., Rasouli, F., Hajaligol, M., "Application of nanoparticle iron oxide in cigarette for simultaneous CO and NO removal in the mainstream smoke", Beitraege zur Tabkforschubg International 21 (1) (2004), 1] They described the use of an additive formed by iron oxide nanoparticles, which is generated in situ while the cigarette is burning, and which is capable of increasing the degree of conversion of CO and NO to CO ₂ and N ₂ , respectively. On the other hand, organic potassium salts can also be used as additives, which allow reducing the yield of CO, nicotine and dry nicotine-free particulate matter (NFDPM) [Li, C ₁ Parry, A., "Potassium organic salts as burn additives ¡n cigarettes", Beitraege zur Tabkforschubg International 20 (5) (2003), 341].

Other patents or scientific publications have been found describing the use of zeolites as tobacco additives. Thus, Cvetkovic et al. [Cvetkovic, N, Adnadjevich, B., Nikolic, M, "Catalytic reduction of NO and NO _x content in tobaceous smoke", Beitraege zur Tabkforschubg International 20 (1) (2002), 43) use a catalyst based on zeolite Cu- ZSM-5 in order to reduce the amount of NO and NO _x in the mainstream of tobacco smoke. This additive can be incorporated into the filter or mixed directly with tobacco and, according to the mechanism proposed by these authors, it is the adsorption properties of the additive and the diffusivity therein that determine its activity. There are also other authors who propose the use of certain additives, based on their adsorption capacity. For example, Jianhua et al. [Jianhua, Z., Ying, W., Yilun, W, "Mesopore solid alkali, mesopore functional material, its preparation method and application", CN 1460641, 2003-12-10] describe the use of an alkaline solid catalyst and a functional material based on a silicon-based mesoporous molecular sieve (for example MCM-41 or NaA, NaY and ZSM-5 zeolites), which contains a lantanoid, actinoid or transition metal, for the reduction of nitrosamines by selective adsorption. The use of zeolites for the reduction of NFDMP and polynuclear aromatic hydrocarbons (PAH) has also been revealed by Radojicic et al. [Radojicic, V., Nikolic, M., Adnadevic, B., Jovanovic, A., "Selective reduction of PAH content in cigarette tobaceous smoke by catalytic cracking process", Physical Chemistry, 2004]. Other inventions also related to the foregoing are, for example, Shahtyar et al. [Shahryar RR, Firooz Rasouli M., Hajaligol RM, "Tobacco cut filler including metal oxide supported particles", US 2005/0126583 June 15, 2005], which describes the procedure for preparing particle-based additives that include supported metal oxides. In said study, the additive is formed by combining the particles and a solution of the metal oxide precursor with the composition of the smoking article. Other patents, such as Stanbridge Ia [Stanbridge KA, "Incorporating additives into cigarette rods", GB 2229079, September 19, 1990], focus on the procedure used to incorporate tobacco additives. In this case, the additive is deposited in the tobacco stream during the cigarette making process, using a device that allows the material to be deposited, in powder form or in the form liquid, in suspension or as foam. On the other hand, any of the aforementioned additives can also be added directly to tobacco using the cigarette rolling machines described by Pascual [Pascual UA, "Cigarette rolling and tobacco rolling machines", U 200202253, September 18, 2002]. EP 740907 describes the use of zeolitic, natural and synthetic materials, as additives to reduce toxic compounds in tobacco smoke. In this invention, a smoking article is claimed which is comprised of a filter, tobacco and a wrapper. The additives, with different characteristics depending on the destination of the additive, are incorporated into both the filter and tobacco. Thus, while the additive that is introduced into the filter is hydrophobic, hydrophilic materials are preferred for mixing with tobacco. These hydrophilic additives are used saturated with water and consist of zeolites X, Y, L, mordenite and BETA, and are added to tobacco, using or not adhesion agents, such as silica gel. At high temperatures, these materials act as catalysts and have positive effects in order to reduce the toxic compounds generated in the combustion of tobacco, without affecting the taste of it.

Another similar patent [Meier, MW, "Process for treating tobáceo with catalitically active material for reducing toxic components in tobaceous smoke", EP 1, 234,511 26.02.2001] focuses on the process of preparing cigarettes using the aforementioned additives, No need to use adherent agents. The procedure consists of 1) distributing the catalytically active material in the tobacco and 2) pressing said material on the tobacco. It is therefore desirable to have additives for mixing with tobacco, to reduce the amount of toxic and carcinogenic substances present in tobacco smoke. Additives that on the other hand avoid, or at least minimize, some of the drawbacks known in the art.

EXPLANATION OF THE INVENTION

According to a first aspect of the invention, it provides the use of an additive for mixing with tobacco, to reduce the amount of toxic and carcinogenic substances present in tobacco smoke, where said additive is selected from the group formed by: a) zeolites in their acidic, sodium or iron-exchanged forms; b) mesoporous aluminosilicates in their acidic, sodium or iron-exchanged forms; c) mixtures of the above materials with oxides of iron, cerium or zirconium; and d) mixtures of the above materials.

In accordance with another aspect, the invention provides a composition comprising any form of blond, black, leaf, sting, rolling tobacco (RYO), pipe filling tobacco (MYO), pipe tobacco or any other article capable of being smoked, with at least one additive selected from: a) zeolites in their acidic, sodium and exchanged forms with iron; b) mesoporous aluminosilicates in their acidic, sodium and iron-exchanged forms; c) mixtures of the above materials with oxides of iron, cerium or zirconium; d) mixtures of the above materials.

In accordance with another aspect, the invention provides a method for reducing the amount of toxic and carcinogenic compounds present in tobacco smoke, which comprises the use of the additives of the present invention in dry blending with tobacco.

According to another aspect, the invention provides a method for preparing the composition according to the invention, which comprises contacting the tobacco with the appropriate amount of additive, and mixing both components.

According to another aspect, the invention provides the use of a KIT that provides the adequate amount of catalyst for the "in situ" preparation of the tobacco-additive mixture described above. The kit of the invention comprises separate compartments for tobacco and additive, in the appropriate proportions, as well as instructions for its preparation. DESCRIPTION OF THE INVENTION:

In accordance with an embodiment of the present invention, the use of an additive belonging to the group consisting of the following materials is described, to reduce the presence of toxic and carcinogenic compounds in tobacco smoke: acid, sodium or exchanged forms with iron of BETA zeolite (H-BETA, Na-BETA, Na-Fe-BETA, Na-Ce-BETANa-Zr-BETA); acid, sodium or exchanged forms with zeolite iron ZSM-5 (H-ZSM-5, Na-ZSM-5, Na-Fe-ZSM-5, Na-Ce-ZSM-5, Na-Zr-ZSM-5) ; acidic, sodium or exchanged forms with zeolite iron USY (H-USY, Na-USY, Na-Fe-USY, Na-Ce-USY, Na-Zr-USY); acid, sodium or exchanged forms with mesoporous aluminosilicate iron MCM-41 (Na-MCM-41, Na-Fe-MCM-41, Na-Ce-MCM-41, Na-Zr-MCM-41); acidic, sodium or exchanged forms with MCM-22 alumninosilicate iron (Na-MCM-22, Na-Fe-MCM-22, Na-Ce-MCM-22, Na-Zr-MCM-22); mixtures of the above with oxides of Fe, Ce or Zr; and mixtures of these materials.

Preferably, the additive used is selected from the group consisting of H-ZSM-5, Na-ZSM-5, Na-Fe-ZSM-5, Na-Ce-ZSM-5, Na-Zr-ZSM-5, H- USY, Na-USY, Na-Fe-USY, Na-Ce-USY, Na-Zr-USY, Na-MCM-41, Na-Fe-MCM-41, Na-Ce-MCM-41, Na-Zr- MCM-41, Na-MCM-22, Na-Fe-MCM-22, Na-Ce-MCM-22, Na-Zr-MCM-22, mixtures of the above with Fe, Ce or Zr oxides; and mixtures of these materials.

In accordance with an embodiment of the present invention, the additive is selected from the group formed by the sodium and iron exchanged forms of the zeolites or aluminosilicates, mixtures of Fe, Ce or Zr oxides with any of the above materials, and mixtures of the above.

In a more preferred embodiment, the additive is selected from Na-MCM-41, Na-Fe-MCM-41, Na-Ce-MCM-41, Na-Zr-MCM-41, mixtures thereof with oxides of Fe, Ce or Zr; and mixtures of these materials.

The compositions of the invention are characterized by containing as additives those materials described above. Thus, according to an embodiment of the invention, the additive is selected from the group consisting of: a) the acid, sodium and exchanged forms with zeolite iron

BETA: H-BETA, Na-BETA, Na-Fe-BETA; b) the acid, sodium and exchanged forms with zeolite iron ZSM-5: H-ZSM-5, Na-ZSM-5, Na-Fe-ZSM-5; c) the acid, sodium and exchanged forms with zeolite iron USY: H-USY, Na-USY, Na-Fe-USY; d) the acid, sodium and exchanged forms with mesoporous aluminosilicate iron MCM-41: Na-MCM-41, Na-Fe-MCM-41; e) Acid, sodium and exchanged forms with MCM-22 alumninosilicate iron: Na-MCM-22, Na-Fe-MCM-22; f) mixing oxides of Fe, Ce or Zr with any of the above materials; g) mixtures of the above.

Preferably the additive is selected from H-ZSM-5, Na-ZSM-5, Na-Fe-ZSM-5, Na-Ce-ZSM-5, Na-Zr-ZSM-5, H-USY, Na-USY, Na-Fe-USY, Na-Ce-USY, Na-Zr-USY, Na-MCM-41, Na-Fe-MCM-41, Na-Ce-MCM-41, Na- Zr-MCM-41, Na- MCM-22, Na-Fe-MCM-22, Na-Ce-MCM-22, Na-Zr-MCM-22, mixtures of the above with Fe, Ce or Zr oxides; and mixtures of these materials. In an alternative embodiment, the additive is selected from the group consisting of the sodium and iron exchanged forms of the zeolites or aluminosilicates, mixtures of Fe, Ce or Zr oxides with any of the above materials, and mixtures of the above. More preferably, the additive is selected from the group consisting of Na-MCM-41, Na-Fe-MCM-41, Na-Ce-MCM-41, Na-Zr-MCM-41, mixtures thereof with Fe oxides, Ce or Zr; and mixtures of these materials.

In an embodiment of the invention, the composition is characterized in that the additive is in concentrations between 0.5 and 15% by weight with respect to tobacco. Preferably in concentrations between 2 and 7% by weight with respect to tobacco.

As already mentioned, unlike other applications in which zeolites or related materials are also used, in this patent, the additives considered, in powder form, are added and mixed directly with the tobacco sting, without using any type of adhesive agent or any other specific technology for the preparation of the mixtures. Among the additives of the present invention, no toxic components or fibrous materials are included. On the other hand, the use of additives belonging to the aforementioned group of materials allows obtaining significant reductions in the generation of a considerably high number of toxic and carcinogenic compounds generated by smoking tobacco (CO ₁ nicotine, tars, aldehydes, etc.), unlike what is claimed in the documents of the state of the art, where only the reduction of a few compounds (NO and NO _x , in the case of Cvetkovic et al., nitrosamines in the case of Jianhua et al. or NFDMP and polynuclear aromatic hydrocarbons (PAH) in the case of Radojicic et al.). On the other hand, as already mentioned, the materials proposed in this patent cause a very significant reduction in the amount of toxic and carcinogenic compounds present in tobacco smoke, due to their role as cracking catalysts in pyrolysis processes and combustion of tobacco, rather than its adsorbent properties, which is the basis of the mechanism proposed by some of the previous authors [Cvetkovic et al. and Jianhua et al.).

It should be noted that the use of additives and the methodology proposed in this patent leads to significantly higher results than those contained in some of the patents consulted, where the use of some material included in the group previously proposed is also proposed. aforementioned. Thus, for example, the results described by Meier et al. [Meier MW, Jost, W., Scanlan, F., EP 0 740 907] for the generation of tars (tar) or nicotine when the acid and sodium forms of BETA zeolite are used show minimal differences with respect to cigarettes of reference, smoked without additive, while the results observed when using the procedure described in the present patent suppose a very important reduction of said substances. This fact supposes one of the main objectives of the present invention. This improvement is even more noticeable when comparing the results of Meier et al. with those obtained with other materials proposed here, for example with MCM-41. On the other hand, this patent describes and places special emphasis on the drastic reduction of certain very important toxic substances, such as CO, to which reference is not made in any of the reviewed patents that use materials related to those proposed in this work.

The proposed procedure can be used in a highly satisfactory manner with any type of tobacco preparation (blond, black, leaf, sting, rolling tobacco, pipe tobacco and any other items that can be smoked). Notwithstanding the foregoing, the application of a few drops of water, ethanol or any other wetting agent can facilitate the manufacturing process. In addition, as already mentioned, by the described process, reductions of toxic compounds are obtained which are significantly higher than those described in other patents related thereto. It is worth noting that, even in those patents in which the possibility of using additives with or without bonding agents is proposed [Meier MW, Jost, W., Scanlan, F., EP 0 740 907], when describing the different Examples, these are mixed with the tobacco by vaporizing them in the form of a suspension of the zeolite with C-GeI and LC-674, while in the present invention, the zeolites are mixed directly with the tobacco bite and, at most, are added a few drops of ethanol to favor the humidification of the catalyst. On the other hand, in the patent of Meier et al. It is explicitly recognized that in the smoking article, the catalyst is incorporated into tobacco using an adhesive. This fact is very important, since the presence of the adhesive or the mixture of the active element with other components can cause undesirable effects of interparticular diffusion or even partial or total blocking of the pores of the catalyst with the consequent loss of effectiveness.

Regardless of all of the above, for the preparation of cigarettes different types of equipment can be used that facilitate and can improve the incorporation of the additive to the tobacco sting, such as fast or orbital mixers, fluidized beds and entrained beds, among others, as well as sieves to separate and recirculate the additive that had not been fixed on the fibers of tobacco. On the other hand, for other preparations other than conventional cigarettes, where the preparation of the tobacco-additive mixtures must be carried out manually by the smoker himself, a kit comprising separate containers for tobacco and additive can be used. Said kit or dispenser provides the adequate amount of catalyst for the preparation of blond, black, leaf, sting, rolling tobacco, pipe tobacco and any other article that can be smoked. This kit can consist of a blister pack, where each cavity contains the selected amount (between 5 and 70 mg, so that a dosage between 0.5 and 15% of additive is obtained with respect to tobacco, preferably between 2 and 7% by weight, which will usually be consumed in portions of about 1 g of tobacco), individual capsules containing said amounts, a container that includes a calibrated or graduated teaspoon or any other calibrated dispenser.

The present invention describes the use of catalysts that have adequate characteristics from this point of view since they have a non-fibrous morphology, approximately spherical and a particle size or aggregates such that, in the proportions described in the examples, they are observed in the secondary filters used, which constitutes a guarantee that they do not pass through the conventional filter. For other applications, it may be necessary to adjust the particle size to ensure this behavior.

As it has been shown in the previous section, different methods have been described to reduce the amount of toxic and carcinogenic substances from the combustion of tobacco, which are present in the main and secondary currents of the smoke generated by smoke tobacco.

This patent describes the use of certain zeolites and other aluminosilicates and mesoporous solids, in their neutral, acidic or exchanged forms with metal ions, as well as modifications and / or mixtures of these materials with non-toxic metal ions or with oxides of these metals, such as tobacco additives to drastically reduce the amount of toxic and / or carcinogenic compounds that are generated when smoking and that appear in the main and secondary currents of tobacco smoke. These additives also reduce the fraction of condensable and non-condensable products that are generated in the combustion of tobacco without substantially altering its organoleptic characteristics, while the amount of solid residue (coke) in the ashes increases.

These additives, in powder form, can be added and mixed directly with tobacco, without using any type of adhesive or special technology. These are valid and can be used for this purpose for any type of presentation of smoking tobacco directly (packages of conventional cigarettes, cigars, cigars, etc.), as well as for those forms that require prior manipulation to obtain the article that can be smoked (MYO, RYO, pipe tobacco, etc.). Therefore, an object of the present invention refers to the use of additives for the direct elimination of a large part of these undesirable compounds from the gases and condensable products that are part of the tobacco smoke in directly consumable products (packages of conventional cigarettes, cigars, cigars, etc.), as well as a kit comprising separate containers for tobacco and additive. Said kit or dispenser can be used preferentially for those forms that require prior manipulation to obtain the article that can be smoked (rolling tobacco-RYO-, tobacco for filling tube-MYO-, pipe tobacco, etc.).

The additives used in the present invention have the morphological and structural characteristics typical of molecular sieves. Thus, the USY zeolite has smaller Si / Al ratios and larger pore size than the ZSM-5 zeolite, and a structure characterized by bulky, essentially spherical internal cavities ("supercages") connected tetrahedrally through the pore openings , defined by rings of 12 oxygen atoms (12-member rings or 12MR) [Boxiong S., Chunfei W., Rui W., Binbin G. and Cai L., "Pyrolysis of scrap tires with zeolite USY", Journal of Hazardous Materials, in Press (2006)]. The ZSM-5 zeolite features a 10-member ring system (10MR), with a three-dimensional network of interconnected sinusoidal and circular channels, with pore sizes of 5.3x5.6 Á and 5.1x5.5 Á and intersections between the channels of 0.9 nm [N. Kumar, "Synthesis, modification and application of high silica catalysts in the transformation of light hydrocarbons to aromatic hydrocarbons", N. Kumar, Ph. D. thesis, Abo Akademi University, Ábo / Turku, Finland, 1996]. BETA zeolite has a structure with 12MR type holes [JM Newsam, M. MJ. Treacy, WT. Koetsier, Proc. R. Soc. Lond. A, 420 (1988), 375]. This zeolite has a highly disordered structure, consisting of the random growth of polymorphs A and B, with tetragonal and monoclinic symmetries, respectively, usually in an approximate ratio of 60:40 [Q. Li, A. Navrotsky, F. Rey, A. Corma, Micropor. Mater., 59 (2003), 177]. It has two types of straight channels, in the directions / a / and IbI with diameters of 7.3 x 6.8 Á for the tetragonal system and 7.3 * 6.0 A for the monoclinic system, and a sinusoidal channel in the IcI direction, 5.5 * 5.5 Λ The intersection of these channels forms a highly accessible pore system [JC Jansen, EJ. Creyghton, SL Njo, H. Koningsveld and H. Bekkum, Catal. Today, 38 (1997), 205]. The MCM-22 material [MK Rubin, P. Chu, US patent 4954325, 1990] is a relatively recent aluminosilicate, which was first obtained by Rubin et al. in 1990. The structure of the MCM-22 consists in two independent pore systems, one of them composed of two-dimensional channels with 10-member pore openings (10MR) and the other consists of a super-box system with 12-member openings (12MR). Due to this porous structure, the MCM-22 combines the behavior of both systems, 10MR and 12MR ₁ that confer some unusual catalytic properties. The MCM-41 material is also a mesoporous aluminosilicate, which was first synthesized by Beck et al. in 1992 [JS Beck, JC Vartuli, GJ Kennedy and CT Kresge, SE Schramm, Chem. Mater., 6 (1994), 1816]. The MCM-41 has a hexagonal arrangement of mesopores, with a highly regular pore system, of variable size between 1.5 and 10 nm, which confers a considerably high surface area. This property is of great importance for the reduction of the harmful effects of tobacco.

All these materials are widely described in the literature, both in what refers to the procedures for obtaining them, as well as their physicochemical and structural characteristics.

Within the group of materials referred to in this patent, the non-acidic forms, when used as tobacco additives in the manner described in this application, provide excellent results from the point of view of the reduction of the toxic and dangerous products present in tobacco smoke, since they avoid the negative effects associated with the possible hydrolysis of lignocellulosic materials present in tobacco, which can occur when acid forms are used in environments with a high degree of humidity. Table 1 shows the chemical and structural characteristics of some of the additives studied in this application, as a representative example of this type of materials. For all of them, the Si / Al ratio, the external surface and other characteristics can be modified within relatively wide intervals for different purposes, without thereby substantially modifying the behavior and general properties of the material.

Another important aspect is the size and shape of the catalyst particles. Small particle sizes improve contact with the solid and the evolved gases, but can more easily pass through the filters or the tobacco bed and pass into the lungs, so this aspect must be taken into account and this possibility reduced or eliminated. In any case it is very important that these types of additives do not contain compounds or toxic elements or presenting a fibrous morphology that could be harmful to health. The materials used have particle sizes of the order of 0.1-2 μm which, in many cases, are forming aggregates of 20-30 μm. In the experimental conditions used in the examples described in this invention, the materials described, with these particle dimensions, allow to obtain highly satisfactory results from the point of view of the reduction of toxic compounds present in tobacco smoke, without observing a significant presence of particles capable of passing through cigarette filters. However, for other forms of tobacco that can be smoked, it will be necessary to optimize the particle size of the additives so that they are present with a size that is small enough to produce good results, but not so much as to pass through the filters of the cigarette or the bed of tobacco. Throughout the description and the claims the word

"understand" and its variants are not intended to exclude other technical characteristics, additives, components or steps.

For those skilled in the art, other objects, advantages and characteristics of the invention will emerge partly from the description and partly from the practice of the invention. The following examples are provided by way of illustration, and are not intended to be limiting of the present invention.

DETAILED EXHIBITION OF AN EMBODIMENT

Example 1. Comparative study of cigarette smoking with and without additive.

In order to demonstrate the role of the additives proposed in this patent, the following were smoked: a) commercial reference cigarettes and b) cigarettes to which the additives were incorporated, using a smoking machine that operated according to the following operating variables :

Cigarette smoking conditions and analysis of the products generated

• 5 cigarettes are smoked simultaneously, following the specifications of the ISO 3308 standard (puffs of 2 s duration, volume aspirated 35 ml_, frequency of drafts 60 s and pressure loss in the draft less than 300 Pa).

• Cigarettes are conditioned at room temperature and 60% relative humidity, keeping them in a desiccator provided with a saturated solution of sodium nitrite, at least for 48 hours before being smoked.

• During the smoking process, smoke, including CO ₁ CO ₂ and other non-condensable products, passes through the cigarette filter as well as a trap located immediately behind it. The non-condensable products are collected in a Tediar gas bag, which is reserved for subsequent analysis by gas chromatography (GC) and the condensable products are collected in the cigarette filter and in the subsequent trap. In it are retained condensable products that would be directly inhaled by smokers. • The suction pressure of the smoking machine is of the order of 150 cm of H ₂ O.

• The condensable products retained in the trap after the filter are extracted with 2-propanol, ensuring that all the compounds retained in the trap are recovered. The extract is then dried with sodium sulfate and reserved for further GC analysis.

• The determination of the CO and CO ₂ content in the non-condensable fraction is carried out by GC, using a thermal conductivity detector (GC-TCD) and a Porapack Q column, in a SHIMADZU GC-14A device, using a calibration through external patterns. The conditions of the analysis are:

Carrier gas: He

Temperataura injector: 100 ⁰ C

Detector temperature: 1 1O ⁰ C

Injected volume: 250 μL «The remaining non-condensable components are analyzed by GC with flame ionization detector (GC-FID), using a GAS-PRO column and the following conditions:

Carrier gas: He

Injector temperataura: 15O ⁰ C Detector temperature: 23O ⁰ C

Injected volume: 150 μL • The condensable compounds (extracted with 2-propanol) are analyzed by GC with mass spectrometry detector (GC-MS), using an HP-5MS column and the following conditions:

Carrier gas: He Temperataura injector: 5O ⁰ C

Detector temperature: 23O ⁰ C Injected volume: 1 μl_

• For the determination of the quantities obtained of each compound, the integration of the area under the chromatographic peaks is carried out and the corresponding response factors are used.

Conditions for preparing cigarettes

To carry out all the tests, cigarettes were prepared in which the tobacco fiber was mixed manually with the catalyst, aiding with a few drops of ethanol. This operation was performed on a sieve that allowed to separate the catalyst that was not adhered to tobacco, so that a percentage of catalyst was obtained in the nominal mixtures, which corresponded to the amount of initially heavy catalyst, and a real one, which was the finally retained by the sample. Other agents that are alternative to ethanol that can be used to aid in the tobacco-catalyst mixing process are water, glycerin and other similar solvents, which do not affect the properties of tobacco and evaporate with relative ease. Notwithstanding the foregoing, mixtures can also be carried out satisfactorily without using any of these substances.

Characteristics of the samples used

The characteristics corresponding to some examples that allowed to illustrate the results that can be achieved with the use of the proposed additives are presented below. The nominal percentage of each type of additive is indicated. The tobacco used, both in the reference cigarettes and in the different mixtures with the additives, was always a commercial blond tobacco of the same brand.

a) Examples corresponding to different tobacco-additive mixtures In all cases a nominal percentage of 10% by weight of additive is used. Cigarettes were prepared using the procedure described in "cigarette preparation conditions" and using the additives indicated below:

Tobacco

Tobacco + H-MCM-22 10%

Tobacco + Na-MCM-22 10%

Tobacco + Na-Fe-MCM-22 10%

Tobacco + H-MCM-41 10%

Tobacco + Na-MCM41 10%

Tobacco + Na-Fe-MCM41 10%

Tobacco + Na-Fe-MCM-41 + CeO ₂ 10%

Tobacco + H-USY 10%

Tobacco + H-ZSM-5 10%

Tobacco + Beta 10%

Tobacco + Na-Beta 10%

b) Examples corresponding to tobacco-additive mixtures with different concentration of additive

The additive used is in all cases Na-Fe-MCM-41. The percentages by weight of catalyst are indicated. Cigarettes were prepared using the procedure described in "cigarette preparation conditions" and using the nominal concentrations (weight percentage) indicated below:

Results obtained: a) Examples corresponding to different tobacco-additive mixtures

Tables 2, 3 and 4 present the results obtained when smoking cigarettes using the conditions of preparation of cigarettes, smoking conditions and analysis of the products generated and the examples of group a), corresponding to different tobacco mixtures -additive. The values obtained for: - CO and CO ₂ , in mg of compound / cigarette are shown

- quantity of some toxic products, in mg of compound / cigarette

- percentage of liquids, gases and ash generated

- total particulate matter (TPM) in mg / cigarette, calculated as:

_ m _λ - m ₀

" ¹ TPM ~ q where m ₀ is the mass of the trap after the filter, in mg, before smoking my is the mass of the trap after the filter, in mg, after smoking q cigarettes q is the number of cigarettes smoked

Tables 2 to 4 show that the proposed additives, in their acidic, sodium and iron-exchanged forms, as well as their mixtures with oxides of Ce and Zr, when mixed with tobacco in the proportions described, provide a significant reduction of the amount of toxic compounds that appear in tobacco smoke. This reduction in turn implies a decrease in the potential negative effects caused by tobacco smoke in smokers and passive smokers, without causing appreciable changes in the organoleptic properties and taste and consistency of tobacco, and without apparent generation of other undesirable compounds. On the other hand, not only the toxic compounds are reduced, but in general, the total amount of gases and liquids that are formed when smoking the cigarette (total particulate matter, TPM, plus the liquids retained in the filter), while increasing the solid residue along with the ashes. At the end of the process of smoking the cigarette, the additives are retained in the ashes or in the tobacco that has not been smoked. As it has been shown previously, the use of these additives causes a significant reduction of the toxic substances present in tobacco smoke, such as CO, CO ₂ , nicotine, etc., as well as the total amount of liquid and gaseous products. For example, in Table 2 the results obtained for the production of CO and _CO2, expressed as mg of compound / cigarette, to a cigarette reference to mixtures with some of the additives which may be considered representative of the rest is. As can be seen, when the proposed additives were used, reductions of the order of 24-88% were obtained in the amount of CO generated, with respect to the reference cigarette, while the reduction in the formation of CO ₂ can reach the 0-84% On the other hand, according to the data presented in Table 3, and as has already been shown, the materials studied also reduce the total amount of liquid and gaseous products generated, so that, for example, reductions of the order of 37-97% in the MPR are observed, while the solid waste generated increases. Table 4 shows, as an example, the results obtained for the production of some toxic and carcinogenic compounds that appear in tobacco smoke. As can be seen, in most cases, the use of the proposed additives provides a reduction of more than 50% for most of the compounds. For example, when Na-MCM-41 is used as an additive, the following reductions were observed with respect to the reference cigarette: CO ₂ , 81.4%; CO, 84.4%; TPM, 97.1%; glycerin, 32.5%; neofitadian, 72.1%; nicotine, 79.1%; acetone, 57.5%; acetaldehyde, 70.3%; hydroquinone, 79.7%, propionaldehyde, 49.3%; acrolein, 69.1%; crotonaldehyde, 62.2%; isobutyraldehyde, 66.7%, furan, 63.8% and benzene, 62.2%.

All the mixtures described can also be prepared by using fast mixers, fluidized or entrained beds and any other type of equipment that favors the mixing between the tobacco fiber and the additive. Sieves can also be used to separate and recirculate the additive that had not been fixed on the tobacco fibers. On the other hand, for preparations other than conventional cigarettes, where the preparation of the tobacco-additive mixtures must be carried out manually by the smoker himself, a dispenser can be used that provides the adequate amount of catalyst for the preparation of blond tobacco , black, leaf, sting, rolling tobacco, pipe tobacco and any Another item that can be smoked. This dispenser can consist of a blister pack, where each cavity contains the selected quantity (between 5 and 70 mg, so that it is obtained between 0.5 and 7% with respect to tobacco, which will usually be consumed in portions of about 1 g of tobacco ), individual capsules containing said amounts, a container that includes a calibrated or graduated teaspoon or any other calibrated dispenser. To prepare the ready-to-smoke product (MYO, RYO, pipe or other forms), the content of the calibrated dispenser is poured onto the tobacco fiber and carefully mixed with the hand. This procedure guarantees excellent results, as good as those presented in Tables 2 to 4.

Results obtained: b) Examples corresponding to tobacco-additive mixtures with different concentration of additive

The influence of the concentration of the additive in the additive-tobacco mixtures has also been studied. For this, mixtures with a nominal percentage of catalyst comprised between 1 and 10% were prepared, using the procedure described above. By way of example, tables 5 and 6 show the results obtained when Na-Fe-MCM-41 is used as an additive. As can be seen, the best results are achieved when the maximum concentration of additive is used, although in the mixtures with 3-7% excellent results are also obtained, which can be adjusted according to the reduction of the desired toxic compounds.

Table 1. Typical values of different properties of some of the additives studied in this patent ( ^a BJH; ^b BET method, adsorption isotherms of N ₂ ; ^c method t, adsorption isotherms of N ₂ ; ^d measured at P / Po = O.995, adsorption isotherms of N ₂ ; ⁶ XRF, ^f TPD of NH ₃ , ⁹ NMR).

Table 1.- Continuation.

Table 2. CO ₂ and CO content in tobacco smoke generated under controlled conditions.

Table 3. TPM obtained by smoking tobacco under controlled conditions.

Table 4. Generation (mg compound / cigarette) of different toxic compounds present in the gases and in the condensable products retained in the trap after the filter when smoking tobacco under controlled conditions.

Table 4. Continuation.

Table 5. TPM obtained by smoking tobacco under controlled conditions.

Table 6. Generation (mg compound / cigarette) of different toxic compounds present in the gases and in the condensable products retained in the trap after the filter when smoking tobacco under controlled conditions.

[OR

Table 6. Continuation.

Claims

1. Use of an additive for mixing with tobacco, characterized in that said additive is selected from the group consisting of: a) zeolites in their acidic, sodium or iron-exchanged forms; b) mesoporous aluminosilicates in their acidic, sodium or iron-exchanged forms; c) mixtures of the above materials with oxides of iron, cerium or zirconium; and d) mixtures of the above materials to reduce the amount of toxic and carcinogenic substances present in tobacco smoke

2. Use according to the preceding claim, characterized in that the additive is selected from the group consisting of: a) the acid, sodium and exchanged forms with BETA zeolite iron: H-BETA, Na-BETA, Na-Fe-BETA ; b) the acid, sodium and exchanged forms with zeolite iron ZSM-5: H-ZSM-5, Na-ZSM-5, Na-Fe-ZSM-5; c) acid, sodium and exchanged forms with zeolite iron

USY: H-USY, Na-USY ₁ Na-Fe-USY; d) Acid, sodium and exchange forms with mesoporous aluminosilicate iron MCM-41: Na-MCM-41, Na-Fe-MCM-

41; e) Acid, sodium and exchanged forms with MCM-22 alumninosilicate iron: Na-MCM-22, Na-Fe-MCM-22; f) mixing oxides of Fe, Ce or Zr with any of the above materials; g) mixtures of the above.

3. Use according to claim 2, characterized in that the additive is selected from the group consisting of H-ZSM-5, Na-ZSM-5, Na-Fe-ZSM-5, Na-Ce-ZSM-5, Na-Zr-ZSM-5, H-USY, Na-USY, Na-Fe-USY, Na-Ce-USY, Na-Zr-USY, Na-MCM-41, Na-Fe-MCM-41, Na- Ce-MCM-41, Na-Zr- MCM-41, Na-MCM-22, Na-Fe-MCM-22, Na-Ce-MCM-22, Na-Zr-MCM-22, mixtures of the above with oxides of Fe, Ce or Zr; and mixtures of these materials.

4. Use according to any of the preceding claims 1 to 3, characterized in that the additive is selected from the group consisting of the sodium and iron exchanged forms of the zeolites or aluminosilicates, mixtures of Fe, Ce or Zr oxides with any of the above materials, and mixtures of the above.

5. Use according to any of the preceding claims 1 to 4, characterized in that the additive is selected from the group consisting of Na-MCM-41, Na-Fe-MCM-41, Na-Ce-MCM-41, Na- Zr-MCM-41, its mixtures with Fe ₁ Ce or Zr oxides; and mixtures of these materials.

6. Use of the additive according to any of the preceding claims 1 to 5, characterized in that the toxic and carcinogenic compounds are reduced in the main stream and in the secondary stream of tobacco smoke.

7. Composition comprising any form of blond tobacco, black, leaf, sting, rolling tobacco (RYO), tobacco for filling tubes (MYO), pipe tobacco or any other article that can be smoked, with at least one additive selected from the group consisting of: e) zeolites in their acidic, sodium and iron-exchanged forms; f) mesoporous aluminosilicates in their acidic, sodium and iron-exchanged forms; g) mixtures of the above materials with oxides of iron, cerium or zirconium; h) mixtures of the above materials.

8. The composition according to claim 7, characterized in that the additive is selected from the group consisting of: h) acid, sodium and exchanged forms with zeolite iron

BETA: H-BETA, Na-BETA, Na-Fe-BETA; i) the acid, sodium and exchanged forms with zeolite iron ZSM-5: H-ZSM-5, Na-ZSM-5, Na-Fe-ZSM-5; j) acid, sodium and exchanged forms with zeolite iron

USY: H-USY, Na-USY, Na-Fe-USY; k) the acid, sodium and exchanged forms with mesoporous aluminosilicate iron MCM-41: Na-MCM-41, Na-Fe-MCM-41;

I) Acid, sodium and exchanged forms with MCM-22 alumninosilicate iron: Na-MCM-22, Na-Fe-MCM-22; m) mixing of Fe, Ce or Zr oxides with any of the above materials; n) mixtures of the above.

9. The composition according to claim 8, characterized in that the additive is selected from the group consisting of H-ZSM-5, Na-ZSM-5, Na-Fe-

ZSM-5, Na-Ce-ZSM-5, Na-Zr-ZSM-5, H-USY, Na-USY, Na-Fe-USY, Na-Ce-USY, Na-Zr-USY, Na-MCM- 41, Na-Fe-MCM-41, Na-Ce-MCM-41, Na-Zr- MCM-41, Na-MCM-22, Na-Fe-MCM-22, Na-Ce-MCM-22, Na- Zr-MCM-22, mixtures of the above with oxides of Fe, Ce or Zr; and mixtures of these materials.

10. The composition according to any one of the preceding claims 7 to 9, characterized in that the additive is selected from the group formed by the sodium and iron-exchanged forms of the zeolites or aluminosilicates, mixtures of Fe, Ce or Zr oxides with any of the above materials, and mixtures of the above.

11. The composition according to any of the preceding claims 7 to 10, characterized in that the additive is selected from the group consisting of Na-MCM-41, Na-Fe-MCM-41, Na-Ce-MCM-41, Na -Zr-MCM-41, its mixtures with oxides of Fe, Ce or Zr; and mixtures of these materials.

12. The composition according to any of the preceding claims 7 to 11, characterized in that the additive is in concentrations between 0.5 and 15% by weight with respect to tobacco.

13. The composition according to claim 12, characterized in that the additive is in concentrations between 2 and 7% by weight with respect to tobacco.

14. The composition according to any of the preceding claims 6 to 13, characterized in that the additive has a particle size between 0.1-2 μm.

15. Method of preparing the composition according to any of the preceding claims 6 to 14, characterized in that it comprises contacting the tobacco with the appropriate amount of additive, and mixing both components.

16. The process according to claim 15, characterized in that water, ethanol, glycerin or mixture thereof is also added.

17. The method according to any of the preceding claims 15 to 16, characterized in that rapid mixers, fluidized beds, entrained beds or any other type of equipment that favor the mixing between the tobacco fiber and the additive are used; and sieves to separate and recirculate the additive that had not been fixed on the tobacco fibers.

18. Kit for the preparation of the composition according to any of the preceding claims 6 to 14, characterized in that it comprises separate compartments for tobacco and additive, in the appropriate proportions, and instructions for its preparation.