JPS6322185B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a remover that selectively removes carbon monoxide from tobacco smoke generated during smoking without adversely affecting the aroma and taste of tobacco. (Industrial application field) Carbon monoxide (hereinafter also simply referred to as CO), which is generally generated by incomplete combustion of carbon or carbon-containing compounds.
Because it binds tightly to hemoglobin in the blood and significantly inhibits the blood's role in oxygen absorption and transport, it can cause acute poisoning symptoms such as headaches and dizziness, and in severe cases can even lead to death. Also, CO
It is said that long-term exposure to these substances can cause chronic heart disease. This CO is contained in a few percent of the so-called mainstream smoke that smokers directly inhale when they smoke cigarettes, and although it is significantly diluted by the air that is simultaneously inhaled before reaching the human lungs. It is believed that this contributes to the chronic increase in the concentration of CO-bound hemoglobin in the blood of smokers, and there is a desire to reduce CO from tobacco smoke. (Prior Art) From this point of view, many attempts have been made to reduce the CO concentration in mainstream cigarette smoke.
Many proposals have been made in patent specifications and the like. These proposals can be broadly classified as follows. 1. A method of selecting and using raw materials that generate less CO. 2. A method of suppressing the generation of CO by creating holes in the filter part or using high porosity wrapping paper, or reducing the generated CO by diffusion from the wrapping paper. 3. A method of reducing CO by oxidizing or capturing it by filling or holding an oxidation catalyst, oxidizing agent, or adsorbent in a filter part or cigarette holder, etc. Among methods 1 to 3 above, methods 1 and 2 have been extensively studied to date, and some of them have been commercialized. However, the current situation is that no definitively effective method has yet been found for method 3. The reasons for this include the extremely short contact time between tobacco smoke and the oxidation catalyst and other fillers, the presence of inhibiting components such as moisture and tar in the surrounding environment, and the toxicity of the fillers themselves. In addition to the necessity, there are many other problems, such as the fact that the aroma and taste of cigarettes is impaired. Examples of substances that have been proposed for the purpose of reducing CO in tobacco smoke by method 3 above include the so-called hopcalite-based composite oxide catalyst (Japanese Patent Laid-Open No. 1983-1972), which is mainly composed of a composite of copper oxide and manganese oxide.
72988, JP-A-53-96399) and metal oxide catalysts such as manganese oxide (Brit.pat. No. 1315374)
However, all of them are significantly deactivated by moisture, and follow-up tests show almost no removal effect. or,
There are also many disclosures regarding precious metal supported catalysts (Japanese Patent Application Laid-Open No. 1983-1999)
-73344, 53-149192, 55-137039)
However, as a result of further testing, it became clear that sufficient effectiveness could not be expected in removing CO from smoke. However, on the other hand, the so-called Wacker type catalyst, which was developed for the purpose of synthesizing acetaldehyde using ethylene as a raw material and using oxygen in the gas phase, has high activity against CO oxidation. ,
A mechanism has been proposed in which water is effectively introduced into the redox system and CO is oxidized by oxygen in the gas phase (J.Air Pollution Control Association). Assoc.) 28, 253
(1978)). This Watzker type catalyst basically uses PdX ₂ or M ₂ PdX ₂ (X is a halogen atom, M is a group Ia metal in the periodic table) as an active compound for the substrate, and also as a redox pair for the substrate.
CuX ₂ (X is a halogen atom) is used. The presence of moisture, which is generally considered undesirable in low-temperature CO oxidation using metal oxidation, works effectively in this type of catalyst;
It can be said to be an ideal catalyst when used under humid conditions such as CO reduction. Inventions using such Watzker-type catalysts for CO reduction include the addition of copper salts other than copper halides (mainly copper nitrate) to promote reoxidation of palladium salts reduced by CO. A method of increasing activity by adding three components (Japanese Patent Application Laid-open No. 50-33990), an example of adding tin ions, etc. to promote reoxidation (Japanese Patent Application Laid-open No. 110400/1983), 1
There is an example (Japanese Unexamined Patent Publication No. 55-97252) in which a copper salt of 20% is coexisting. The Watzker type catalyst seen in these inventions related to CO oxidation is a homogeneous system as a solution,
Or alumina, silica, aluminosilicate,
It is used as a heterogeneous catalyst supported on various carriers such as molecular sieves and activated carbon. However, when a catalyst in which the Watzker type catalyst according to the conventional invention is supported on the above-mentioned carrier, which is known as a catalyst carrier, is used for the purpose of reducing CO in mainstream cigarette smoke, the effect is not necessarily sufficient. On the other hand, when γ-alumina is used as a carrier, the oxidation activity of CO is high, and the reduction rate of CO in tobacco smoke when filled in the filter part of the cigarette is also extremely high, but it does not significantly reduce the aroma and taste of tobacco smoke. It has the disadvantage of lowering This is considered to be due to the physical and chemical properties of the γ-alumina surface. Furthermore, when activated carbon alone is used as a carrier, although no adverse effect on tobacco flavor was observed, there is a drawback that a sufficient CO reduction effect cannot be obtained. [Problems to be solved by the invention] The present invention has been made in view of the above-mentioned problems of conventional catalysts for reducing CO2.
The purpose of the present invention is to provide a CO removal agent that has a high reduction effect and does not adversely affect the aroma and taste of tobacco smoke. When actually applying a CO remover to cigarettes, mainly cigarettes, the CO remover is
It is necessary to hold the CO oxidation catalyst on a carrier and fill it in the filter or holder of a cigarette. Therefore, the present inventors investigated in detail the relationship between the type of carrier on which the catalyst should be supported, the oxidation activity of CO, and the effect on the aroma and taste of tobacco smoke regarding the Watzker type catalyst consisting of a combination of palladium salt and copper salt. As a result of research, it was discovered that when a mixed composition of metal oxide and activated carbon is used as a carrier, a highly active CO removal catalyst can be obtained that does not adversely affect the aroma and taste, leading to the present invention. Ivy. [Means for Solving the Problems] That is, the agent for removing carbon monoxide from tobacco smoke of the present invention is a catalyst in which a palladium salt and a copper salt are supported on a carrier, and the carrier is a metal oxide. and activated carbon. In the present invention, the activated carbon used as a carrier composition is not particularly limited, and vegetable activated carbon or coal-based activated carbon such as coconut shell charcoal, palm charcoal, and softwood charcoal is preferably used. In addition, the specific surface area of these activated carbons is approximately 500 to 1300 according to the BET measurement method.
m ² /g. Next, metal oxides that are mixed with activated carbon include magnesium oxide (MgO), aluminum oxide (Al ₂ O ₃ ), silica (SiO ₂ ), and pentoxide (P ₂ O ₅ ).
and transition metal oxides or composite oxides, or silicate minerals containing one or more of magnesium or aluminum in the composition, such as kaolinite (Al ₂ O ₃・2SiO ₂・2H ₂ O), asbestos (MgO・SiO ₂ ),
Zepiolite (Mg ₈ H ₂ (Si ₄ O ₁₁ ) ₃・3H ₂ O), zeolite (Na ₂ Al ₂ Si ₃ O ₁₀・xH ₂ O), diatomaceous earth (mainly composed of SiO ₂ , with Al ₂ in the composition) _O3 , _{Fe2O3 ,}
Contains MgO and CaO. ) etc. are preferably used. Further, as the transition metal oxide, for example, copper oxide (CuO), zirconium oxide (ZrO ₂ ), titanium oxide (TiO ₂ ), nickel oxide (NiO), cobalt oxide (C ₀ O), etc. are preferably used. be able to. Next, any known method may be used to solidify the activated carbon and the metal oxide to form a carrier. For example, the activated carbon powder and the metal oxide powder may be mixed in an aqueous solution of a water-soluble polymer such as polyvinyl alcohol, silica gel, alumina sol, water glass, etc. Knead and harden, form into granules of about 20 to 60 mesh, and pre-dry to about 100 mesh.
A method such as heat treatment at a temperature of .degree. C. or higher may be employed. In this case, the amount of metal oxide contained in the mixed composition of activated carbon and metal oxide is preferably 10 to 90% by weight, more preferably 30 to 70% by weight. Next, in the present invention, the supported amount of the catalyst component contained in the CO removing agent is 0.01 to 0.01 for palladium salt.
A good range is 0.2 m mol/g, and for copper salts, 0.1 to 2.0 m mol/g, preferably 0.4 to 1.0 m
The range of mol/g is good. Furthermore, as types of palladium salts and copper salts, chlorides, nitrates, sulfates, etc. can be used. As a method for supporting the above metal salt catalyst on a mixed composition carrier of metal oxide and activated carbon, the pore volume of the carrier is measured in advance by the BET method, etc., and palladium is added to a volume of water approximately equal to that volume. The so-called pore-filling method involves dissolving the salt and copper salt and absorbing the entire amount into the pores of the carrier, or by immersing the carrier in a mixed aqueous solution of palladium salt and copper salt.
A method such as the so-called impregnation method, in which the solution is concentrated using a rotary evaporator or the like and salts are precipitated onto the carrier, can be applied, but the latter impregnation method is more convenient and It is excellent because there is no need to set any particular restrictions on the concentration. The CO remover of the present invention prepared as described above is used by filling it into a cigarette filter or a cigarette holder. The present invention will be explained in more detail with reference to Examples below. Using the CO remover of the present invention not only makes it possible to significantly reduce CO in tobacco smoke, but also improves the aroma and taste of tobacco smoke. has no negative effect,
In fact, it was found to have excellent effects such as reducing the irritation caused by smoke. (Example) (1) Preparation of carriers First, six types of catalyst carriers A according to the present invention made of a mixed composition of metal oxide and activated carbon were prepared by the following method.
~F was prepared. Preparation example 1 Coconut husk charcoal crushed to a particle size of 200 mesh or less
After thoroughly mixing 10g and 10g of diatomaceous earth powder with a dry mixer, 35ml of silica sol with a concentration of 30% by weight is obtained.
was added. After thoroughly kneading this mixture, 120
It was dried and solidified at ℃. Next, the carrier A was obtained by pulverizing the particles to a particle size of 20 to 60 meshes. Preparation Example 2 15 g of coal-based activated carbon pulverized to a particle size of 200 mesh or less and 5 g of silica-alumina powder were thoroughly mixed in a dry mixer, and then 35 ml of silica sol having a concentration of 20% by weight was added and further thoroughly kneaded. This kneaded material
After drying at 120°C, the temperature was raised to 300°C and heat treated for an additional 2 hours. Next, let it cool and crush it to 20 to 60
The particle size was made uniform in the mesh to obtain carrier B. Preparation Example 3 After thoroughly mixing 10 g of coal-based activated carbon pulverized to a particle size of 200 mesh or less and 10 g of cupric oxide (CuO), 30 ml of silica sol having a concentration of 30% by weight was added and further thoroughly kneaded. This kneaded material was dried at 120°C, then ground, and the particle size was adjusted to 20 to 60 mesh.
I got it. Adjustment example 4 Coconut husk charcoal crushed to a particle size of 200 mesh or less
Magnesium pyrophosphate (2MgO・P ₂ O ₅ ) in 10g
10 g of powder and 35 ml of No. 3 sodium silicate were added, thoroughly kneaded, and then dried at 150°C. Then crush it,
The particle size was adjusted to 20 to 60 mesh to obtain carrier D. Preparation example 5 Coal charcoal crushed to a particle size of 200 mesh or less
After adding 30ml of silica sol with a concentration of 30% by weight to 10g and 10g of kaolinite powder and thoroughly kneading,
Dry at 120°C. Then, heat treatment was further performed at 800° C. for 2 hours in a nitrogen stream. After cooling, crush it for 20 minutes.
A carrier E was obtained by adjusting the particle size to ~60 mesh. Preparation example 6 Coal charcoal crushed to a particle size of 200 mesh or less
After thoroughly mixing 10 g of zirconium oxide (ZrO ₂ ), 5 g of zirconium oxide (ZrO 2 ) prepared to the same particle size, and 5 g of nickel oxide (NiO) in a dry method, a silica sol with a concentration of 30% by weight was prepared.
30 ml was added, thoroughly kneaded, and dried at 120°C. Next, this was further heat-treated at 300° C. for 2 hours, and then pulverized to a particle size of 20 to 60 mesh to obtain carrier F. (2) Preparation of carrier-supported catalyst For each 3 g of the above-mentioned supports A to E prepared by the method in (1), 2 m of a 0.1 mol/concentration palladium chloride aqueous solution, 1 m of a 1 mol/concentration cupric chloride aqueous solution, and 1 m of 1 mol/concentration copper nitrate aqueous solution
A mixed aqueous solution consisting of the following was added to impregnate the carrier with the catalyst component consisting of the palladium salt and the copper salt. Each was dried at 40°C to obtain carrier-supported catalysts A', B', C', D' and E' of the present invention. Regarding carrier F, 1 mol/copper salt per 3 g of carrier
aqueous solutions of cupric chloride and copper sulfate, respectively.
Catalyst F' was obtained in the same manner as in the case of supports A to E except that 1.5 m was used. (3) Test for removing CO from tobacco smoke 200 mg each of the carrier-supported catalysts of the present invention obtained in (2) were filled into the filter portion of a product cigarette (trade name Highlight). Connect this cigarette to an automatic smoking device and set it under standard smoking conditions (35m suction/1 puff,
Six puffs were inhaled at a rate of 2 seconds/1 puff), and the CO concentration in the resulting mainstream smoke gas was measured using a non-dispersive infrared spectrophotometer (ND-IR). Furthermore, using γ-alumina and coconut shell charcoal as carriers, A to E
In the same way as in the case of the carrier, the CO concentration was measured in the same way using the catalyst supporting the catalyst components as a comparison sample, and
The CO concentration was similarly measured using a filter filled with the same amount of coconut husk charcoal as a control. From the above measured values, the CO removal rate relative to the control was calculated and the results were as shown in Table 1.

[Table] The CO removal rate was calculated using the following formula. CO removal rate (%) = (1 - CO concentration of sample / CO concentration of control) x 100 As is clear from the results in Table 1, the filter filled with the carrier-supported catalyst of the present invention has only coconut husk charcoal as a carrier. The catalyst showed a CO removal rate 2 to 2.7 times higher than that of the γ-alumina support. (4) Flavor and taste test for tobacco smoke Samples obtained in the same manner as in (3) were evaluated by 10 trained specialized sensory panel members, and the results are shown in Table 2. .

【table】

[Table] As seen in the evaluation in Table 2, the carrier-supported catalyst of the present invention has almost no negative effect on the flavor of tobacco smoke, and all the panelists agreed that the catalyst had almost no negative effect on the aroma and flavor of tobacco smoke, and all the panelists agreed that there was no difference in flavor and aroma from the control product, the coconut husk charcoal filter. It was rated as excellent. On the other hand, it has been found that the γ-alumina carrier catalyst has a significant negative effect on the aroma and taste of cigarettes. (Effects of the invention) As described above in detail including the examples,
A mixed composition of metal oxide and activated carbon is used as a carrier,
The CO removal catalyst of the present invention, which is made by supporting a mixture of palladium salt and copper salt, can significantly reduce CO in smoke without reducing the aroma and taste of tobacco smoke.

Claims (1)

[Claims] 1. A catalyst in which a palladium salt and a copper salt are supported on a carrier, characterized in that a mixed composition of a metal oxide and activated carbon is used as the carrier. Carbon monoxide remover. 2. The cigarette according to claim 1, wherein the metal oxide is an oxide or composite oxide containing one or more metals selected from the group consisting of magnesium, aluminum, silicon, phosphorus, and transition metal elements. Carbon monoxide remover in smoke. 3. The carbon monoxide remover in tobacco smoke according to claim 1, wherein the metal oxide is a silicate mineral containing at least either magnesium or aluminum.