Low-temperature catalytic fragrance-releasing composite catalyst, preparation method and application thereof

Abstract

The present application relates to the field of light industry and chemical material preparation technology, in particular to a low-temperature catalytic fragrance-releasing composite catalyst, a preparation method and application thereof. The preparation method of the low-temperature catalytic fragrance-releasing composite catalyst comprises: modifying HTS titanium-silicon molecular sieve with a metal organic salt solution to prepare a composite metal oxide titanium-silicon molecular sieve catalyst. The present application has high stability and adsorption and low cost, can catalyze the fragrance release of tobacco sheet at low temperature, effectively solves the problems of high fragrance release temperature of existing heat-not-burn electronic cigarettes, reduces the fragrance release temperature of tobacco sheet, reduces the release of harmful components in smoke, and reduces the energy consumption of smoking utensils.

Description

Technical Field

[0001] This invention relates to the field of light industry and chemical material preparation technology, specifically to a low-temperature catalytic aroma release composite catalyst, its preparation method, and its application. Background Technology

[0002] The market size of heated tobacco products (HTMS) is increasing year by year. Due to their simulated taste and reduced harm compared to traditional cigarettes, more and more people are accepting and using HTMS. The core temperature of traditional cigarettes generally exceeds 800℃, and most of the harmful smoke components in cigarettes are produced when tobacco is heated to high temperatures. Related studies have shown a positive correlation between the production of harmful substances in tobacco and the heating temperature. Therefore, lowering the temperature of the tobacco can significantly reduce the production of harmful smoke.

[0003] Currently, the heating temperature of common heated tobacco products is around 350℃. Due to insufficient release of aroma substances in the smoke under low temperature conditions, it is difficult to further reduce the heating temperature of heated tobacco products. Considering that the essence of the aroma release process is an oxidation-reduction reaction, the production of tobacco aroma substances can be promoted by adding a suitable catalyst, thereby further reducing the tobacco heating temperature. Traditional catalysts mainly include alkali metal catalysts, metal oxide catalysts, transition metal catalysts, etc. Among them, alkali metal catalysts generally include lithium, sodium, potassium, calcium, etc. (Chen Wenxuan, Liu Peng, Li Xueqin, Li Yanling, Zhou Zhengzhong, Lei Tingzhou. Research progress on catalysts for catalytic cracking of biomass tar [J]. Forest Products Industry, 2022, 59(03):41-48; Qi Guolu. Mechanism and application of alkali metal catalytic carbon smoke combustion [D]. Hebei University of Science and Technology, 2016.). However, due to the low melting point of alkali metals, they are prone to sintering and agglomeration at high temperatures, resulting in reduced activity. At the same time, due to their own Strong alkalinity makes them unsafe for use in tobacco sheets. While a wide variety of metal oxide catalysts exist, allowing selection based on reaction conditions, their poor dispersion and tendency to agglomerate limit the contact area with reactants, reducing catalytic efficiency. Transition metals, also precious metals, possess high catalytic activity and reaction stability. For example, invention CN104370879A utilizes precious metal catalytic pyrolysis to prepare diene nicotine; however, the high price of precious metals and the high preparation cost, coupled with substantial upfront investment, limit their widespread industrial application. Therefore, developing a low-cost, highly stable, and adsorbent catalyst capable of catalyzing aroma release from tobacco sheets at low temperatures is necessary and urgently needed. This would reduce the harmful components of the smoke by lowering the heating temperature of the tobacco sheets, reduce the inlet temperature of the smoke to improve taste, and ultimately enhance the quality of new tobacco sheets. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a method for low-temperature catalytic aroma release from tobacco sheets. The low-temperature catalytic aroma release composite catalyst and its method provided by this invention enable low-temperature catalytic aroma release from tobacco sheets, are low-cost, and possess high stability and adsorption capacity. This effectively solves the problem of high aroma release temperatures in existing heated tobacco products, reduces the aroma release temperature of tobacco sheets, decreases the release of harmful components in the smoke, and lowers the energy consumption of smoking devices.

[0005] In a first aspect, the method for preparing the low-temperature catalytic aroma release composite catalyst provided by the present invention includes: modifying HTS titanium-silicon molecular sieve with a metal-organic salt solution to prepare a composite metal oxide titanium-silicon molecular sieve catalyst.

[0006] The low-temperature catalytic aroma release method for tobacco sheets proposed in this invention can reduce the aroma release temperature of tobacco sheets, decrease the release of harmful components in the smoke, and reduce the energy consumption of smoking devices, effectively solving the problem of high aroma release temperature in existing heated tobacco products. By combining a hollow mesh titanium-silicon molecular sieve (HTS) with good adsorption properties and a large contact area with a metal oxide possessing high catalytic activity and high stability, the aroma release temperature of the tobacco sheet is effectively reduced, thereby reducing the release of harmful components in the smoke from novel tobacco sheets, lowering the inlet temperature of the smoke, and improving the taste. Furthermore, it can further reduce the energy consumption of heated tobacco products and increase the usage time of smoking devices. This invention uses titanium-silicon molecular sieve (HTS) as a catalyst carrier, and then prepares a low-temperature catalyst by loading the metal oxide of this invention. The catalyst is then mixed with the tobacco sheet matrix. The operation process is relatively simple. This not only solves the problem of insufficient adsorption of volatile organic compounds by traditional metal oxides and improves catalytic efficiency, but also greatly reduces the cost compared to precious metal catalysts, making it highly valuable.

[0007] Preferably, the organometallic salt in the metal-organic salt solution includes one or more of copper acetate, ammonium molybdate, nickel nitrate, phosphotungstic acid, magnesium acetate, and copper tungstate.

[0008] Preferably, the concentration of the organometallic salt solution is 1% to 20% by mass fraction, and more preferably 1% to 5%. In this invention, by using a salt solution with a mass fraction of 1% to 5%, especially between 2.5% and 3.5%, the modifier can be more completely attached to the titanium-silicon molecular sieve, increasing the specific surface area of ​​the catalyst, thereby better increasing the catalytic efficiency and obtaining a titanium-silicon molecular sieve catalyst with better catalytic rate.

[0009] Further preferred, the preparation method of the low-temperature catalytic aroma release composite catalyst provided by the present invention includes: mixing and stirring the metal-organic salt solution with the HTS titanium-silicon molecular sieve, then allowing it to settle and precipitate, filtering, drying the filter material at a temperature of 100-130℃, preferably 110-125℃, for 15-25 min, preferably 15-20 min, and then calcining it at a temperature of 500-600℃ for 8-12 h to obtain the composite metal oxide titanium-silicon molecular sieve catalyst. In the present invention, by adopting the above method and reasonably controlling the drying temperature and drying time, drying separation can be carried out more quickly, reducing the drying time; by reasonably controlling the calcination temperature and calcination time, the catalytic components of the modifier can be more completely converted, better reducing energy consumption while increasing the proportion of effective components of the catalyst.

[0010] Preferably, the preparation method of the low-temperature catalytic aroma release composite catalyst provided by the present invention includes: preparing a hollow mesh HTS titanium-silicon molecular sieve using TS-1 titanium-silicon molecular sieve as raw material.

[0011] Further preferred, the preparation method of the low-temperature catalytic aroma release composite catalyst provided by the present invention includes: adding a mixture of tetraethyl orthosilicate and tetrabutyl titanate to a tetrapropylammonium hydroxide solution, evaporating to form a synthetic gel, crystallizing, filtering, washing, drying, and then calcining to obtain TS-1 titanium-silicon molecular sieve; then mixing and stirring the TS-1 titanium-silicon molecular sieve, sulfuric acid solution, and TPAOH solution, crystallizing, filtering, washing, drying, and calcining at high temperature to obtain the HTS titanium-silicon molecular sieve. In the present invention, a physicochemically stable titanium-silicon molecular sieve HTS precursor can be prepared by hydrolysis prepolymerization of tetraethyl orthosilicate and tetrabutyl titanate, crystallization, drying, and calcination. Then, the interstitial spaces of the titanium-silicon molecular sieve are expanded by the action of sulfuric acid, allowing the organic salt solution to better adhere to the network structure of the titanium-silicon molecular sieve, increasing the proportion of catalytic cores and making the catalytic effect more efficient.

[0012] Further optimization involves adding a mixture of tetraethyl orthosilicate and tetrabutyl titanate to a tetrapropylammonium hydroxide solution, evaporating at 80–85°C to form a synthetic gel, crystallizing at 170–180°C for 20–25 hours, filtering and washing, drying at 110–120°C for 6–8 hours, and then calcining at 550–600°C for 6–8 hours to obtain TS-1 titanium-silicon molecular sieve; then mixing and stirring the TS-1 titanium-silicon molecular sieve, sulfuric acid solution, and TPAOH solution, crystallizing the resulting gel at 50–60°C for 36–48 hours, cooling to room temperature and filtering, washing the solid product with a large amount of deionized water, drying at 120°C for 12 hours, and then calcining at 550–600°C for 8 hours to obtain the HTS titanium-silicon molecular sieve. In this invention, the HTS titanium-silicon molecular sieve prepared using the above-mentioned optimized conditions has a stable spatial structure, can be stored for a long time at room temperature, and has uniform particle size, making it less prone to aggregation in tobacco and exhibiting good dispersibility.

[0013] Preferably, the molar ratio of the tetraethyl orthosilicate, the tetrabutyl titanate, and the tetrapropylammonium hydroxide is 1.00–1.05: 0.35–0.40: 1.00–1.10.

[0014] Preferably, the mass-to-volume ratio of the TS-1 titanium-silicon molecular sieve, sulfuric acid solution, and TPAOH solution is 1.00–1.05 g: 0.10–0.11 mL: 1.00–1.20 mL.

[0015] Preferably, the concentration of the sulfuric acid solution is 15% to 25%, and the concentration of the TPAOH solution is 20% to 30%.

[0016] Secondly, the composite catalyst provided by the present invention includes a catalytic core and a low-temperature catalytic support; the low-temperature catalytic support is an HTS titanium-silicon molecular sieve, and the catalytic core is a metal oxide; preferably, the composite catalyst is prepared by the preparation method of the low-temperature catalytic aroma release composite catalyst.

[0017] In this invention, the low-temperature catalytic support includes, but is not limited to, titanium-silicon molecular sieve structures such as TS-1 and HTS, and other network structures such as MOFs materials can also be used as catalyst supports; the catalytic core includes, but is not limited to, metal oxides such as copper, molybdenum, tungsten, magnesium, iron, and manganese, and other metals with catalytic effects such as platinum, gold, and palladium can also be used as catalytic cores. The composite catalyst is preferably prepared by the preparation method of the low-temperature catalytic aroma release composite catalyst provided by this invention.

[0018] Thirdly, the present invention provides a composite catalyst obtained by the preparation method of the low-temperature catalytic aroma release composite catalyst, or the application of the composite catalyst in the low-temperature catalytic aroma splitting and aroma release of electronic cigarette tobacco sheets.

[0019] Preferably, this includes mixing at least one of the composite catalysts with electronic cigarette tobacco sheets.

[0020] More preferably, the amount of the composite catalyst added to the electronic cigarette tobacco sheet is 1% to 30%, preferably 5% to 10%.

[0021] The beneficial effects of this invention are at least as follows: A titanium-silicon molecular sieve with a porous network structure serves as the catalyst adsorption carrier, while a metal oxide with high catalytic activity serves as the catalytic core. The combination of these two components yields a composite titanium-silicon molecular sieve catalyst, which possesses excellent adsorption properties and high catalytic activity. Compared to current single-form metal oxide catalysts, the composite catalyst, due to its network structure, can better adsorb and capture large organic molecules in tobacco sheets, making it easier to contact the catalytic core during heating, thereby achieving catalytic oxidation at lower temperatures and forming the unique aroma components of tobacco. Furthermore, due to the large specific surface area of ​​the titanium-silicon molecular sieve, while improving the aroma release performance of tobacco sheets, the amount of catalytic core used can be greatly reduced, thus lowering production costs. This catalyst is directly mixed with the reconstituted tobacco substrate for e-cigarettes, making its use simpler and more convenient, and not conflicting with the production process of reconstituted tobacco for e-cigarettes. However, this also means that the catalyst for e-cigarette tobacco sheets becomes a disposable consumable. Using traditional transition metals such as platinum, gold, palladium, and rhodium is extremely expensive, while using the modified titanium-silicon molecular sieve of this invention is very inexpensive, greatly improving economic efficiency. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 The effect of 1% HTS modification on the rate of tobacco pyrolysis provided in this embodiment of the invention;

[0024] Figure 2 The effect of 5% HTS modification on the rate of tobacco pyrolysis provided in this embodiment of the invention;

[0025] Figure 3 The pyrolysis mass of tobacco sheets provided in the embodiments of the present invention at various mass fractions of copper acetate under HTS conditions. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the present invention. Where specific techniques or conditions are not specified in the embodiments, they shall be performed in accordance with the techniques or conditions described in the literature in the art, or in accordance with the product instructions. Reagents or instruments used where the manufacturer is not specified are all conventional products that can be purchased through legitimate channels.

[0027] The following examples are used to illustrate the present invention, but are not intended to limit the scope of the invention.

[0028] All raw materials used in the following examples are commercially available.

[0029] In the following examples of the present invention, the catalytic effect is tested by the weight loss rate of tobacco sheets, and the test conditions are controlled by the tobacco reaction temperature at 200℃, 250℃, 300℃, and 350℃; and the reaction time is 1 min.

[0030] In the following examples of this invention, the tobacco powder was provided by Shandong Zhongyan Yizhong Tobacco, and it is consistent with the commercially available tobacco sheet products of the company. To ensure the accuracy of the experimental data, the tobacco powder was used for testing. The reagents used were purchased from Sinopharm Chemical Reagent Co., Ltd., the electric thermostatic drying oven used was purchased from Shanghai Jinghong Experimental Equipment Co., Ltd., and the high-temperature box-type resistance furnace used was purchased from Daoxu Yanguang Instrument Equipment Factory, Shangyu District, Shaoxing City.

[0031] Example 1

[0032] 10 ml of tetrapropylammonium hydroxide was added to 30 ml of deionized water and stirred at room temperature for 1 h. Then, a mixture of 30 ml of tetraethyl orthosilicate and 0.5 ml of tetrabutyl titanate was added dropwise. The mixture was heated to 50 °C and stirred until clear. After clarification, the temperature was raised to 80 °C to evaporate the alcohol. Then, it was crystallized at 180 °C for 24 h. After cooling, it was filtered, washed with water, and dried to obtain a white solid. The solid was then calcined in a muffle furnace at 600 °C for 12 h to obtain the carrier TS-1. TS-1 was added to a sulfuric acid solution and stirred. The mixture was then added to a tetrapropylammonium hydroxide (TPAOH) solution. The resulting gel was crystallized at 50 °C for 48 h, cooled to room temperature, filtered, and the solid product was washed with deionized water, dried at 120 °C for 12 h, and then calcined at 550 °C for 8 h to obtain HTS.

[0033] Example 2

[0034] Dissolve 1g of phosphotungstic acid in 99g of deionized water and stir until dissolved. Add 10g of the titanium-silicon molecular sieve HTS prepared by the above method to the phosphotungstic acid aqueous solution and stir at room temperature for 12h. Let the stirred titanium-silicon molecular sieve turbid liquid stand for 2h and then filter. Place the filter in a drying oven and dry at 110℃ for 30min. Place the dried product in a muffle furnace and calcine at 550℃ for 10h to obtain 1% phosphotungstic acid modified titanium-silicon molecular sieve H3[P(W3O 10 )4]@HTS.

[0035] Examples 3-4

[0036] The same method as in Example 2 was used, except that the 1% phosphotungstic acid aqueous solution was replaced with a 1% ammonium molybdate aqueous solution and a 1% copper acetate aqueous solution, respectively.

[0037] Example 5

[0038] Dissolve 3g of copper acetate in 97g of deionized water and stir for 10min. Add 10g of the titanium-silicon molecular sieve HTS prepared by the above method to the prepared copper acetate aqueous solution and stir for 8h at room temperature. Let the stirred titanium-silicon molecular sieve turbid liquid stand for 2h and then filter. Place the filter in a drying oven and dry at 120℃ for 20min. Place the dried product in a muffle furnace and calcine at 600℃ for 8h to obtain 3% copper acetate modified titanium-silicon molecular sieve Cu(CH3COO)2@HTS.

[0039] Examples 6-9

[0040] The method is the same as in Example 5, except that the concentration of the 3% copper acetate aqueous solution is changed to 1%, 2%, 4% and 5%, respectively.

[0041] Example 10

[0042] Dissolve 5g of ammonium molybdate in 95g of deionized water and stir until dissolved. Add 10g of the titanium-silicon molecular sieve HTS prepared by the above method to the ammonium molybdate aqueous solution and stir overnight at room temperature. Let the stirred titanium-silicon molecular sieve turbid liquid stand for 4 hours and then filter. Place the filter in a drying oven and dry at 120℃ for 30 minutes. Place the dried product in a muffle furnace and calcine at 550℃ for 12 hours to obtain 5% ammonium molybdate modified titanium-silicon molecular sieve (NH)MoO@HTS.

[0043] Example 11

[0044] The method described in the same way as in Example 10 is used, except that the 5% ammonium molybdate aqueous solution is replaced with a 5% phosphotungstic acid aqueous solution.

[0045] Example 12

[0046] Take 0.25g of tobacco powder. Considering that the catalysts all reach their maximum catalytic effect and reduce measurement errors, the amount added in this embodiment is relatively large. In actual production, it is added according to the requirements. Specifically, 1% concentration of modified ammonium molybdate, copper acetate, titanium phosphotungstic acid silicate molecular sieve (1% (NH)MoO@HTS, 1% Cu(CH3COO)2@HTS, 1% H3[P(W3O]) is added at 10% of the tobacco powder mass. 10 )4]@HTS)0.025g, which were respectively labeled as No. 1 1% ammonium molybdate modified molecular sieve, No. 2 1% copper acetate modified titanium silicon molecular sieve, and No. 3 1% phosphotungstic acid modified titanium silicon molecular sieve, and No. 4 without the addition of modified catalyst. The specific proportions are shown in Table 1.

[0047] Table 1. Comparative Experimental Setup for 1% Modified Titanium-Silica Molecular Sieves

[0048] Serial Number 1 2 3 4 Tobacco powder mass / g 0.25 0.25 0.25 0.25 Added catalyst mass / g 0.025 0.025 0.025 0 Total weight / g 0.275 0.275 0.275 0.25

[0049] The tobacco powder was mixed evenly with the modified catalyst, and then baked at 200℃, 250℃, 300℃, 350℃ and 400℃ for 60s in sequence. The mass of each batch was recorded, and the rate of mass reduction was used to reflect the catalytic effect. The experimental data are shown in Table 2. Since the catalyst was already baked at high temperature for a long time during the preparation process, its mass can be considered constant in this experiment and the following experiments. To facilitate comparison of the experimental data, the mass of the catalyst itself was removed from the recorded data. Therefore, the mass reduction is the mass reduction due to tobacco powder oxidation, which can be approximated as the tobacco oxidation effect. The mass change curve is shown in Table 2. Figure 1 As shown.

[0050] Table 2. Mass change of tobacco powder with temperature under 1% modified catalyst.

[0051] Serial Number 1 2 3 4 Tobacco powder mass / g 0.25 0.25 0.25 0.25 200℃ 0.17 0.16 0.15 0.14 250℃ 0.13 0.12 0.13 0.10 300℃ 0.09 0.06 0.09 0.09 350℃ 0.07 0.05 0.07 0.08 400℃ 0.06 0.04 0.06 0.03

[0052] Comparison of the experiments showed that the rate of mass reduction and oxidation was lower than that of the blank control group before 300℃. Between 300℃ and 350℃, the catalytic rate of each experimental group increased significantly, and the effects of all three groups were higher than those of the blank control group. Since the aroma release temperature of reconstituted tobacco sheets is mostly concentrated around 350℃, it is evident that all three catalysts possess certain low-temperature catalytic effects. Among them, the copper acetate-modified titanium-silicon molecular sieve showed the best effect.

[0053] Example 13

[0054] The same experimental method as in Example 12 was used, except that the 1% low-temperature catalyst was replaced with a 5% low-temperature catalyst, the addition amount was changed to 20% of the tobacco powder mass, and the heating time was reduced to 30s. The configurations are shown in Table 3. Number 1 is 5% ammonium molybdate modified molecular sieve, number 2 is 5% copper acetate modified titanium silicate molecular sieve, number 3 is 5% phosphotungstic acid modified titanium silicate molecular sieve, and number 4 is without modified catalyst. The changes in tobacco powder mass are shown in Table 4.

[0055] Table 3. Comparative Experimental Configuration Table for 5% Modified Titanium-Silica Molecular Sieves

[0056] Serial Number 1 2 3 4 Tobacco powder mass / g 0.25 0.25 0.25 0.25 Added catalyst mass / g 0.05 0.05 0.05 0 Total weight / g 0.30 0.30 0.30 0.25

[0057] Table 4. Mass change of tobacco powder with temperature under the action of 5% modified catalyst.

[0058]

[0059]

[0060] Its mass change curve is as follows Figure 2 As shown in the figure, the experimental data shows that among the 5% concentration modified titanium-silicon molecular sieve catalysts, only copper acetate showed good catalytic performance. The catalytic effects of ammonium molybdate and phosphotungstic acid were similar to those of the blank group. This indicates that excessively high concentrations of modifiers cannot improve catalytic efficiency, and the appropriate concentration of modifier has a significant impact on the catalytic effect.

[0061] Example 14

[0062] The same experimental method as in Example 12 was used, except that the low-temperature catalyst was replaced with 1%, 2%, 3%, 4%, and 5% copper acetate-modified titanium-silicon molecular sieve catalysts, with an addition amount of 10% by mass. The baking time was 50 seconds, and the configuration table was similar to that in Table 1, so it will not be described in detail here. They are numbered 1 to 5 respectively. The changes in the mass of the smoke powder are shown in Table 5.

[0063] Table 5. Data on mass reduction of tobacco powder under different concentrations of copper acetate-modified titanium-silicon molecular sieve catalysts.

[0064] Serial Number 1 2 3 4 5 200℃ 0.04 0.05 0.04 0.05 0.05 250℃ 0.06 0.07 0.07 0.07 0.08 300℃ 0.07 0.08 0.08 0.08 0.09 350℃ 0.15 0.16 0.18 0.16 0.14 400℃ 0.18 0.19 0.2 0.18 0.17

[0065] The relationship between its mass reduction and temperature is as follows: Figure 3 As shown, the relationship between its catalytic effect and concentration is approximately a normal distribution, therefore its catalytic effect is better at a concentration of 3%.

[0066] Example 15

[0067] Take 0.25g of tobacco powder, and add 0.05g each of copper oxide, iron oxide, gold powder, unmodified titanium silicate molecular sieve HTS, and 3% copper acetate modified titanium silicate molecular sieve according to 20% of the tobacco powder mass. Allocate the experimental numbers 1 to 5 in sequence, and the blank control experiment is number 6. The configuration table is shown in Table 6.

[0068] Table 6. Different Catalyst and Tobacco Powder Configurations

[0069] Serial Number 1 2 3 4 5 6 Tobacco powder mass / g 0.25 0.25 0.25 0.25 0.25 0.25 Added catalyst mass / g 0.05 0.05 0.05 0.05 0.05 0 Total weight / g 0.275 0.275 0.275 0.275 0.275 0.25

[0070] The samples were placed in a muffle furnace at 300℃ and baked for 2 minutes, and their masses were measured to be 0.081, 0.093, 0.095, 0.103, 0.063, and 0.097, respectively. Analysis of the above data shows that copper oxide and the 3% titanium-silicon molecular sieve modified catalyst have good catalytic effects on tobacco powder. This is because copper has a better catalytic effect on the pyrolysis of organic matter compared to other metals. The titanium-silicon molecular sieve itself did not exhibit catalytic activity; on the contrary, it hindered the oxidation of tobacco powder. This is because the addition of the titanium-silicon molecular sieve adsorbs oxygen from the air, affecting the contact between the tobacco powder and oxygen, thus reducing the effect. The results for iron oxide and gold powder were similar to those in the blank experiment, indicating that the catalytic effect of iron oxide and transition metals on tobacco powder was not significant.

[0071] Experimental Example 1

[0072] The product of this invention is a fine powder catalyst with stable physicochemical properties. During the production and preparation process, it has undergone high-temperature baking for a long time, which has completely removed organic matter. Therefore, the properties will not change during product transportation and storage. However, it is necessary to pay attention to moisture prevention to prevent it from clumping.

[0073] Because of its stable chemical properties, it can be added as needed during the production process. In this experiment, tobacco sheet samples were prepared using the slurry method. The amount added was divided into 7 groups according to 1%, 5%, 10%, 15%, 20%, 25%, and 30%, and the specific configurations are as follows.

[0074] Prepare a tobacco sheet slurry by taking 10g of tobacco powder, 5g of food-grade high-viscosity glutinous rice glue, 15g of deionized water, 5g of calcium carbonate, and 0.5g of carboxymethyl cellulose. Take 3g of each slurry and add 0.01g, 0.05g, 0.10g, 0.15g, 0.20g, 0.25g, and 0.30g of 3% copper acetate-modified titanium silicate molecular sieve, respectively, and stir until homogeneous. Group the samples into 7 groups. Then, evenly spread each group of samples into a 50mm × 50mm stainless steel groove and dry in a 110℃ constant temperature drying oven for 10 minutes. After drying, the tobacco sheet experimental samples can be obtained.

[0075] Based on the above method, titanium-silicon molecular sieve modified catalysts with different addition amounts can be prepared during the tobacco sheet production and processing. The above examples are only recommended addition methods. In addition, when preparing tobacco sheet samples using the papermaking method, it can be added to the tobacco sheet matrix to play a corresponding role.

[0076] Test Methods: The experiment primarily used pyrolysis rate as the reference. Considering experimental error, this invention used a relatively large number of experimental samples as test objects. Pyrolysis mass was tested using a 0.01% balance supplemented by DSC. Gas chromatography was used to analyze the pyrolysis components of tobacco sheets. To ensure the consistency of experimental data, all experiments were conducted at room temperature (25°C) and standard atmospheric pressure, with the heating device maintained under aerobic conditions. Considering experimental safety, the entire experimental process was conducted under ventilated conditions.

[0077] As shown in the figure, different modifiers have varying degrees of influence on the experimental catalytic effect. Figure 1 It is quite evident that low concentrations of the modifier have a limited effect in the early stages of aroma release in tobacco sheets, but a significant effect in the main aroma release phase. Higher concentrations of the modifier lower the catalytic temperature. Figure 2 It can be seen that rapid pyrolysis begins when the catalytic temperature is reduced to 250℃, but the pyrolysis rate decreases as the temperature increases, gradually approaching that of the blank control experiment. This indicates that the catalytic effect and catalytic temperature are both related to the concentration of the modifier. Figure 3 The experiment shows the effect of different concentrations of copper acetate modifier on the pyrolysis of tobacco sheets. It is not difficult to see that the catalytic effect of the modifier in the main aroma release temperature range is normally distributed with respect to the concentration. The experimental results show that the 3% copper acetate modifier has a good effect. Example 15 is a comparison of the catalytic effect of the present invention with that of commonly used catalysts. The composite titanium-silicon molecular sieve catalyst provided by the present invention has a better catalytic effect than the catalysts used in the existing methods.

[0078] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A method for preparing a low-temperature catalytic aroma release composite catalyst, characterized in that, include: A mixture of tetraethyl orthosilicate and tetrabutyl titanate was added to a tetrapropylammonium hydroxide solution and evaporated at 80-85°C to form a synthetic gel. The gel was then crystallized at 170-180°C for 20-25 hours, filtered, washed, and dried at 110-120°C for 6-8 hours. Finally, it was calcined at 550-600°C for 6-8 hours to obtain TS-1 titanium-silicon molecular sieve. The TS-1 titanium-silicon molecular sieve, sulfuric acid solution, and TPAOH solution were then mixed and stirred. The resulting gel was crystallized at 50-60°C for 36-48 hours, cooled to room temperature, filtered, and the solid product was washed, dried, and then calcined at 550-600°C to obtain a hollow network structure HTS titanium-silicon molecular sieve. The hollow mesh structure of the HTS titanium-silicon molecular sieve was mixed and stirred with a copper acetate solution of 1% to 5% by mass, then allowed to settle and filtered. The filtered material was dried at 100 to 130°C for 15 to 25 minutes, and then calcined at 550 to 600°C for 8 to 12 hours to obtain a composite metal oxide titanium-silicon molecular sieve catalyst. The composite metal oxide titanium-silicon molecular sieve catalyst is used for low-temperature catalytic aroma release of electronic cigarette tobacco sheets at 300 to 350°C.

2. The preparation method of the low-temperature catalytic aroma release composite catalyst according to claim 1, characterized in that, A mixture of tetraethyl orthosilicate and tetrabutyl titanate was added to a tetrapropylammonium hydroxide solution and evaporated at 80-85°C to form a synthetic gel. The gel was then crystallized at 170-180°C for 20-25 hours, filtered, washed, and dried at 110-120°C for 6-8 hours. Finally, it was calcined at 550-600°C for 6-8 hours to obtain TS-1 titanium-silicon molecular sieve. The TS-1 titanium-silicon molecular sieve, sulfuric acid solution, and TPAOH solution were then mixed and stirred. The resulting gel was crystallized at 50-60°C for 36-48 hours, cooled to room temperature, filtered, and the solid product was washed with a large amount of deionized water. It was dried at 120°C for 12 hours and then calcined at 550-600°C for 8 hours to obtain the HTS titanium-silicon molecular sieve.

3. A composite catalyst, characterized in that, The composite catalyst is prepared by the method described in claim 1 or 2 for preparing the low-temperature catalytic aroma release composite catalyst.

4. The application of the composite catalyst obtained by the preparation method of the low-temperature catalytic aroma release composite catalyst according to claim 1 or 2 in the low-temperature catalytic aroma splitting and aroma release of electronic cigarette tobacco sheets.

5. The application according to claim 4, characterized in that, include: At least one of the composite catalysts described in claim 3 is mixed with electronic cigarette tobacco sheets.

6. The application according to claim 5, characterized in that, The composite catalyst is added to the electronic cigarette tobacco sheet at an amount of 1 wt.% to 30 wt.%.

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