Reconstituted tobacco leaf, and method of making and using same

Abstract

The application provides a kind of reconstituted tobacco and its preparation method and application, the preparation method includes the following steps: (1) after mixing metal oleate, template agent, surfactant and solvent, solid material is obtained by pyrolysis treatment, the supercrystal metal oxide is obtained by calcining treatment to the solid material;(2) after etching treatment to the supercrystal metal oxide, the etching material obtained is graphitized, and mesoporous graphene skeleton material is obtained;(3) the mesoporous graphene skeleton material, tobacco raw material, adhesive and additive are mixed, and the reconstituted tobacco is obtained by post-processing.The method prepared by the application has good moisture retention and uniformity of heating, and the reconstituted tobacco is not easy to absorb moisture, and the mesoporous graphene skeleton material in the reconstituted tobacco has abundant pore structure and specific surface area, which can regulate water release and smoke release, so as to achieve the effect of moisture retention and flavor enhancement.

Description

Technical Field

[0001] This invention belongs to the field of tobacco manufacturing technology, and relates to a reconstituted tobacco leaf, its preparation method, and its application. Background Technology

[0002] The ordinary manufacturing process used in the reprocessing of tobacco leaves is largely just a physical recombination process of raw materials. In terms of chemical composition, the tobacco sheets obtained by this method are not much different from the tobacco dust and stems used as raw materials. The chemical components that affect the taste are still retained in the tobacco leaves. For example, tobacco cell wall substances and proteins are the main chemical components that are significantly detrimental to the internal quality of tobacco leaves.

[0003] Tobacco cell wall substances play a skeletal role in ordinary tobacco leaves, stems, and tobacco sheets. They are mainly composed of structurally stable, insoluble substances, including organic compounds such as cellulose, hemicellulose, lignin, and pectin, accounting for approximately 30% of the dry matter in flue-cured tobacco leaves and about 40% in tobacco stems. These large organic molecules that form the skeletal structure can negatively impact the intrinsic quality and flavor of tobacco, such as the throat irritation caused by lower aldehydes produced during pyrolysis.

[0004] CN109007958A discloses a tobacco roasting aroma substance, its preparation method, and its application. The method involves adding a polyol and an organic acid-metal salt complex to tobacco powder raw materials, stirring until homogeneous, and reacting at 150–250°C for 0.5–3 hours. The resulting product is then added to an organic solvent, ultrasonically extracted for 10–60 minutes, followed by shaking extraction for another 10–60 minutes. After centrifugation, the supernatant is filtered through an organic filter membrane, and the filtrate is subjected to vacuum distillation to remove the organic solvent, yielding the tobacco roasting aroma substance. This tobacco roasting aroma substance, when combined with isosorbide and applied to tobacco materials, effectively improves the material's moisture retention, as well as the comfort and harmony of cigarettes.

[0005] CN112120271A discloses the preparation of a malt tobacco flavoring and its application in tobacco. The malt tobacco flavoring can reduce the off-flavors of cigarettes, reduce the irritation of cigarettes, increase the sweetness and permeability of cigarettes, and improve the quality of cigarettes.

[0006] The above solutions, which involve adding additives to cigarettes to improve their moisture retention or enhance their aroma, can achieve some effect, but they do not fundamentally solve the problem, resulting in no significant improvement in the user experience. Summary of the Invention

[0007] The purpose of this invention is to provide a reconstituted tobacco leaf, its preparation method, and its application. The reconstituted tobacco leaf prepared by the method of this invention has good moisture retention and uniform heating. The reconstituted tobacco leaf is not prone to moisture absorption. The mesoporous graphene framework material in the reconstituted tobacco leaf has abundant pore structure and specific surface area, which can regulate the slow release of moisture and the release of smoke, thereby achieving the effects of moisture retention and aroma enhancement.

[0008] To achieve this objective, the present invention adopts the following technical solution:

[0009] In a first aspect, the present invention provides a method for preparing reconstituted tobacco leaves, the method comprising the following steps:

[0010] (1) After mixing metal oleate, template agent, surfactant and solvent, a solid material is obtained by pyrolysis treatment, and the solid material is calcined to obtain supercrystalline metal oxide;

[0011] (2) After etching the supercrystalline metal oxide, the resulting etched material is graphitized to obtain a mesoporous graphene framework material.

[0012] (3) The mesoporous graphene framework material, tobacco raw material, adhesive and additives are mixed and then post-processed to obtain the reconstituted tobacco.

[0013] This invention prepares carbon-coated two-dimensional supercrystalline metal oxides via a one-step pyrolysis method assisted by a salt template. Calcination removes the carbon coating layer from the surface of the supercrystalline metal oxides, inducing full cross-linking of atomic lattices between the

[100] crystal planes of the supercrystalline metal oxides. While maintaining the initial ordered structure of the supercrystalline, multiple controls are achieved on its microstructure and composition, enabling the carbon-coated two-dimensional supercrystalline metal oxides to be directionally transformed into interconnected porous supercrystals. Then, through etching and graphitization, the interconnected porous supercrystals are transformed into two-dimensional ordered mesoporous carbon frameworks (MCFs), and further, two-dimensional ordered mesoporous graphene-like frameworks (MGFs) are obtained through high-temperature graphitization. MGFs simultaneously satisfy the comprehensive optimization of multiple influencing factors such as graphitization degree, thermal conductivity, and pore structure. This can improve the problem of uneven heating in reconstituted tobacco leaves, leverage the hydrophobic properties of the graphene-like structure surface to solve the problem of easy moisture absorption in reconstituted tobacco leaves, and, based on multi-level pore structure design and surface modification technology, regulate the slow release of moisture and the release of tobacco components, thereby achieving effects such as moisture retention and aroma enhancement.

[0014] Preferably, the metal oleate in step (1) includes any one or a combination of at least two of iron oleate, nickel oleate, cobalt oleate or manganese oleate. Typical but non-limiting combinations include combinations of iron oleate and nickel oleate, combinations of nickel oleate and cobalt oleate, or combinations of nickel oleate and manganese oleate.

[0015] Preferably, the template agent in step (1) comprises sodium chloride particles.

[0016] Preferably, the solvent in step (1) includes n-hexane.

[0017] Preferably, the surfactant in step (1) includes sodium oleate.

[0018] Preferably, the mass ratio of the surfactant to the metal oleate in step (1) is 1:(5-15), for example: 1:5, 1:8, 1:10, 1:12 or 1:15, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0019] The surfactant described in this invention can not only provide a carbon source, but also form complexes with metal ions and serve as a precursor for the pyrolysis formation of metal oxide nanocrystalline supercrystals. When the surfactant content increases, its adhesion force on different crystal faces of the nanocrystalline supercrystal is different, resulting in anisotropy of the growth rate on different crystal faces. This invention controls the growth rate of the

[100] crystal face to be slower than that of other crystal faces by adding a surfactant, thereby forming nanocubes.

[0020] Preferably, the solid-liquid ratio of the metal oleate to the solvent in step (1) is 0.3 to 0.5 g / mL, for example: 0.3 g / mL, 0.35 g / mL, 0.4 g / mL, 0.45 g / mL or 0.5 g / mL, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0021] Preferably, the mass ratio of the metal oleate to the template agent in step (1) is 1:(5-15), for example: 1:5, 1:8, 1:10, 1:12 or 1:15, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0022] Preferably, the temperature of the pyrolysis treatment in step (1) is 300 to 500°C, for example: 300°C, 350°C, 400°C, 450°C or 500°C, etc., not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0023] Preferably, the pyrolysis treatment time in step (1) is 1 to 3 hours, for example: 1 hour, 1.5 hours, 2 hours, 2.5 hours or 3 hours, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0024] Preferably, the pyrolysis treatment in step (1) is followed by cooling, washing and drying.

[0025] Preferably, the detergent used for washing includes deionized water.

[0026] Preferably, the calcination temperature in step (1) is 550 to 650°C, for example: 5550°C, 5850°C, 6050°C, 6250°C or 6550°C, etc. Other unlisted values ​​within this range are also applicable.

[0027] Preferably, the calcination time in step (1) is 1 to 3 hours, for example: 1 hour, 1.5 hours, 2 hours, 2.5 hours or 3 hours, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0028] Preferably, the etching process in step (2) includes the following steps:

[0029] The supercrystalline metal oxide was mixed with ultrapure water and then hydrochloric acid was added. After the reaction, the solution was removed by filtration to obtain a black solid powder. The above steps were repeated until the solution obtained by filtration did not change color, thus obtaining the etching material.

[0030] Preferably, the reaction time is 0.5 to 1.5 hours, for example: 0.5 hours, 0.8 hours, 1 hour, 1.2 hours or 1.5 hours, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0031] Preferably, the temperature of the graphitization process in step (2) is 900 to 1600°C, for example: 900°C, 1000°C, 1200°C, 1400°C or 1600°C, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0032] Preferably, the graphitization treatment time in step (2) is 1 to 3 hours, for example: 1 hour, 1.5 hours, 2 hours, 2.5 hours or 3 hours, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0033] Preferably, the adhesive in step (3) comprises sodium carboxymethyl cellulose.

[0034] Preferably, the additive in step (3) includes glycerol and / or propylene glycol.

[0035] Preferably, the mass ratio of the mesoporous graphene framework material, tobacco raw material, binder and additives in step (3) is (1-5):100:(1-5):(30-50), for example: 1:100:1:30, 2:100:3:40, 3:100:4:35, 5:100:2:40 or 5:100:5:50, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0036] Preferably, the post-processing in step (3) includes centrifugation, rolling, and drying.

[0037] In a second aspect, the present invention provides a reconstituted tobacco leaf, which is obtained by the method described in the first aspect.

[0038] Thirdly, the present invention provides a tobacco article comprising reconstituted tobacco leaves as described in the second aspect.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] The reconstituted tobacco produced by the method of the present invention has good moisture retention and heat uniformity. The reconstituted tobacco is not prone to moisture absorption. The mesoporous graphene framework material in the reconstituted tobacco has abundant pore structure and specific surface area, which can regulate the slow release of moisture and the release of smoke, thereby achieving the effects of moisture retention and aroma enhancement. Attached Figure Description

[0041] Figure 1 The image shows an HRTEM image of a two-dimensional graphene-like framework obtained during the preparation of reconstituted tobacco leaves as described in Example 1.

[0042] Figure 2 The image shows an HRTEM image of a two-dimensional graphene-like framework obtained during the preparation of reconstituted tobacco leaves as described in Example 2.

[0043] Figure 3 The image shows an HRTEM image of a two-dimensional graphene-like framework obtained during the preparation of reconstituted tobacco leaves as described in Example 3.

[0044] Figure 4 The image shows an HRTEM image of a two-dimensional graphene-like framework obtained during the preparation of reconstituted tobacco leaves as described in Example 4. Detailed Implementation

[0045] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0046] The sodium chloride particles and ferric oleate used in the embodiments and comparative examples of this invention were prepared by the following method:

[0047] Weigh 60g of NaCl and dissolve it in 200mL of deionized water. Stir under sonication until the NaCl crystals are completely dissolved to obtain a clear and transparent NaCl solution. Place this solution in a liquid nitrogen tank for rapid freeze-drying. Then, continue to place it in a freeze dryer for three days to thoroughly remove residual moisture. Once the NaCl has transformed from crystalline particles into a fluffy white powder, remove it from the freeze dryer and store it in a desiccated container.

[0048] Add 10.8 g of FeCl3·6H2O to a 1 L three-necked flask, followed by 70 mL of deionized water. Stir thoroughly in an ultrasonic cleaner until the FeCl3·6H2O is completely dissolved. Then, add 90 mL of ethanol, 36.5 g of sodium oleate, and 150 mL of n-hexane. React at 70 °C under reflux for 4 h. After cooling to room temperature, transfer the reaction mixture to a separatory funnel. Add an appropriate amount of deionized water to remove unreacted FeCl3·6H2O and sodium oleate. Shake thoroughly, allow to separate into layers, and remove the lower aqueous layer. Repeat this process 3–5 times. Transfer the remaining organic layer to a round-bottom flask and remove the low-boiling solvent by rotary evaporation. The resulting reddish-brown viscous liquid is ferric oleate, which should be placed in a vacuum oven for later use.

[0049] Example 1

[0050] This embodiment provides a reconstituted tobacco leaf, and the preparation method of the reconstituted tobacco leaf is as follows:

[0051] 0.2 g of ferric oleate was dissolved in 0.5 mL of n-hexane and sonicated to form a reddish-brown ferric oleate solution. The ferric oleate solution, 2 g of NaCl granules, and 20 mg of sodium oleate were thoroughly mixed to obtain an orange-red powder. The powder was placed in a tube furnace and heated at 2 °C for 1 minute under a N2 atmosphere. -1 The temperature was increased to 400℃ at a constant rate, and pyrolysis was carried out for 2 hours. During the calcination process, ferric oleate decomposed into Fe3O4 nanocubes and carbon, while the Fe3O4 nanocubes were orderly assembled on the template surface to form two-dimensional supercrystals. After cooling to room temperature, the material was washed three times with deionized water to remove NaCl particles, yielding a solid material, namely carbon-coated 2D Fe3O4 NCSLs. The solid material was then calcined at 600℃ for 2 hours to obtain supercrystalline iron oxides.

[0052] (2) 200 mg of supercrystalline iron oxide was transferred to a 500 mL Shu Niu bottle. 200 mL of ultrapure water was added first, followed by 200 mL of hydrochloric acid to etch the Fe3O4 crystals inside the supercrystalline structure. The solution was observed to quickly turn light green. After reacting for 1 hour, the acid solution was removed by vacuum filtration. The black powder on the filter membrane was transferred back to the 500 mL Shu Niu bottle for further etching. The above steps were repeated until the solution no longer changed color, indicating that the etching was complete. The obtained black solid powder was then graphitized at 1200 °C for 2 hours to obtain a mesoporous graphene framework material.

[0053] (3) The mesoporous graphene framework material, tobacco raw material, sodium carboxymethyl cellulose and glycerol are mixed in a mass ratio of 5:100:2:40, and the mixture is centrifuged to form tobacco mud. The tobacco mud is then made into cakes and rolled, and dried at 80°C for 5 minutes to obtain the reconstituted tobacco.

[0054] Example 2

[0055] This embodiment provides a reconstituted tobacco leaf, and the preparation method of the reconstituted tobacco leaf is as follows:

[0056] 0.2 g of cobalt oleate was dissolved in 0.6 mL of n-hexane and sonicated to form a reddish-brown cobalt oleate solution. The cobalt oleate solution, 1 g of NaCl particles, and 20 mg of sodium oleate were thoroughly mixed to obtain an orange-red powder. The powder was placed in a tube furnace and incubated at 2 °C for [time missing] minutes under a N2 atmosphere. -1 The temperature was increased to 300℃ at a rate of [missing information], and pyrolysis was carried out at an isothermal temperature for 3 hours. During the calcination process, cobalt oleate decomposed into Fe3O4 nanocubes and carbon, while the Fe3O4 nanocubes were orderly assembled on the template surface to form two-dimensional supercrystals. After cooling to room temperature, the material was repeatedly washed three times with deionized water to remove NaCl particles, yielding a solid material, namely carbon-coated 2D Fe3O4 NCSLs. The solid material was then calcined at 650℃ for 1 hour to obtain supercrystalline cobalt oxide.

[0057] (2) 200 mg of supercrystalline cobalt oxide was transferred to a 500 mL Shu Niu bottle. 200 mL of ultrapure water was added first, followed by 200 mL of hydrochloric acid to etch the Fe3O4 crystals inside the supercrystalline structure. The solution was observed to quickly turn light green. After reacting for 0.5 h, the acid solution after etching was removed by a vacuum filter. The black powder on the filter membrane was transferred back to the 500 mL Shu Niu bottle for further etching. The above steps were repeated until the solution no longer changed color, indicating that the etching was complete. The obtained black solid powder was then graphitized at 900 °C for 3 h to obtain a mesoporous graphene framework material.

[0058] (3) The mesoporous graphene framework material, tobacco raw material, sodium carboxymethyl cellulose and glycerol are mixed in a mass ratio of 1:100:1:30, and the mixture is centrifuged to form tobacco mud. The tobacco mud is then made into cakes and rolled, and dried at 80°C for 5 minutes to obtain the reconstituted tobacco.

[0059] Example 3

[0060] This embodiment provides a reconstituted tobacco leaf, and the preparation method of the reconstituted tobacco leaf is as follows:

[0061] 0.2 g of nickel oleate was dissolved in 0.4 mL of n-hexane and sonicated to form a reddish-brown nickel oleate solution. The nickel oleate solution, 3 g of NaCl granules, and 20 mg of sodium oleate were thoroughly mixed to obtain an orange-red powder. The powder was placed in a tube furnace and heated at 2 °C for 1 minute under a N2 atmosphere. -1The temperature was increased to 500℃ at a rate of [missing information], and pyrolysis was carried out at an isothermal temperature for 1 hour. During the calcination process, nickel oleate decomposed into Fe3O4 nanocubes and carbon, while the Fe3O4 nanocubes were orderly assembled on the template surface to form two-dimensional supercrystals. After cooling to room temperature, the material was repeatedly washed three times with deionized water to remove NaCl particles, yielding a solid material, namely carbon-coated 2D Fe3O4 NCSLs. The solid material was then calcined at 550℃ for 3 hours to obtain supercrystalline nickel oxide.

[0062] (2) 200 mg of supercrystalline nickel oxide was transferred to a 500 mL Shu Niu bottle. 200 mL of ultrapure water was added first, followed by 200 mL of hydrochloric acid to etch the Fe3O4 crystals inside the supercrystalline structure. The solution was observed to quickly turn light green. After reacting for 1.5 h, the acid solution after etching was removed by a vacuum filter. The black powder on the filter membrane was transferred back to the 500 mL Shu Niu bottle for further etching. The above steps were repeated until the solution no longer changed color, indicating that the etching was complete. The obtained black solid powder was graphitized at 1600 °C for 1 h to obtain a mesoporous graphene framework material.

[0063] (3) The mesoporous graphene framework material, tobacco raw material, sodium carboxymethyl cellulose and glycerol are mixed in a mass ratio of 5:100:5:50, and the mixture is centrifuged to form tobacco mud. The tobacco mud is then made into cakes and rolled, and dried at 80°C for 5 minutes to obtain the reconstituted tobacco.

[0064] Example 4

[0065] The only difference between this embodiment and embodiment 1 is that the temperature of the graphitization process in step (2) is 600°C, while the other conditions and parameters are exactly the same as in embodiment 1.

[0066] Example 5

[0067] The only difference between this embodiment and embodiment 1 is that the temperature of the graphitization process in step (2) is 2000℃, while the other conditions and parameters are exactly the same as in embodiment 1.

[0068] Example 6

[0069] The only difference between this embodiment and embodiment 1 is that the mass ratio of the mesoporous graphene framework material to the tobacco raw material in step (3) is 0.5:100. All other conditions and parameters are exactly the same as in embodiment 1.

[0070] Example 7

[0071] The only difference between this embodiment and embodiment 1 is that the mass ratio of the mesoporous graphene framework material to the tobacco raw material in step (3) is 10:100. All other conditions and parameters are exactly the same as in embodiment 1.

[0072] Comparative Example 1

[0073] The only difference between this comparative example and Example 1 is that the calcination treatment in step (1) is not performed; all other conditions and parameters are exactly the same as in Example 1.

[0074] Comparative Example 2

[0075] The only difference between this comparative example and Example 1 is that the graphitization process in step (2) is not performed; all other conditions and parameters are exactly the same as in Example 1.

[0076] Comparative Example 3

[0077] The only difference between this comparative example and Example 1 is that no mesoporous graphene framework material is added; all other conditions and parameters are exactly the same as in Example 1.

[0078] Performance testing: The reconstituted tobacco leaves from the above-described embodiments and the reconstituted tobacco leaves from Comparative Examples 1 and 2 were shredded and added at a ratio of 10% to the leaf blend formula (i.e., blank leaf blend) of a certain brand of cigarettes from Yunnan Tobacco. The mixture was then formed using a cigarette rolling machine. Sensory evaluation was conducted according to the national standard GB5606.4-2005 "Sensory Technical Requirements for Cigarettes". The evaluation results are shown in Table 1.

[0079] Table 1

[0080] Example 1 5 31.0 5.5 11.0 19.5 23.0 95.0 Example 2 5 30.5 5.5 11.0 19.0 23.5 94.5 Example 3 5 30.5 5.5 11.0 19.0 23.5 94.5 Example 4 5 27.5 5.0 10.5 18.5 22.5 89.0 Example 5 5 28.0 5.0 10.5 19.0 21.0 88.5 Example 6 5 26.5 5.0 10.5 18.5 21.5 87.0 Example 7 5 27.5 5.0 10.5 18.5 22.0 88.5 Comparative Example 1 5 24.5 4.5 9.0 17.5 20.0 80.5 Comparative Example 2 5 23.0 4.0 9.0 17.0 20.0 78.0 Comparative Example 3 5 23.5 4.0 8.5 16.0 20.0 77.0

[0081] As can be seen from Table 1, and from Examples 1-7, the total experience score of the cigarettes made from the reconstituted tobacco leaves described in this invention, in terms of overall gloss, aroma, harmony, off-flavors, irritation, and aftertaste, can reach over 87 points. By adjusting the conditions in the preparation process and the ratio of raw materials, the total score can reach over 94.5 points.

[0082] A comparison of Examples 1 and 4-5 shows that the graphitization temperature affects the performance of the reconstituted tobacco in the preparation process of the present invention. Controlling the graphitization temperature between 900 and 1600°C yields better results in reconstituted tobacco. If the graphitization temperature is too low, the graphitization effect is poor, and the material contains a large number of amorphous carbon species, affecting the stability and moisture retention of the reconstituted tobacco. If the graphitization temperature is too high, the specific surface area and pore volume of MGF decrease, the specific surface area and porosity of the material decrease, and the aroma enhancement, moisture retention, and stability of the reconstituted tobacco deteriorate.

[0083] A comparison of Examples 1 and 6-7 shows that the mass ratio of mesoporous graphene framework material to tobacco raw material affects the performance of the reconstituted tobacco leaf prepared according to the present invention. Controlling the mass ratio of mesoporous graphene framework material to tobacco raw material at 1-5:100 yields better reconstituted tobacco leaf results. If the amount of mesoporous graphene framework material added is too low, the improvement effect on the tobacco leaf is not obvious, and the reconstituted tobacco leaf effect is poor. If the amount of mesoporous graphene framework material added is too high, the proportion of the main component in the reconstituted tobacco leaf decreases, resulting in a poor user experience.

[0084] As can be seen from the comparison between Example 1 and Comparative Example 1, the present invention removes the carbon coating layer on the surface of the supercrystalline metal oxide by calcination, induces full cross-linking of atomic lattices between the crystal planes of the supercrystalline metal oxide

[100] , and achieves multiple regulation of its microstructure and composition while maintaining the initial ordered structure of the supercrystal, so that the carbon-coated two-dimensional supercrystalline metal oxide is directionally transformed into an interconnected porous supercrystal.

[0085] As can be seen from the comparison between Example 1 and Comparative Example 2, the present invention transforms interconnected porous supercrystals into two-dimensional ordered mesoporous carbon frameworks (MCFs) through graphitization treatment, and further obtains two-dimensional ordered mesoporous graphene-like frameworks (MGFs) through high-temperature graphitization. MGFs simultaneously satisfy the comprehensive optimization of multiple influencing factors such as the degree of graphitization, thermal conductivity, and pore structure. This can improve the problem of uneven heating of reconstituted tobacco leaves, leverage the hydrophobic properties of the graphene-like structure surface to solve the problem of moisture absorption in reconstituted tobacco leaves, and, based on multi-level pore structure design and surface modification technology, regulate the slow release of moisture and the release of tobacco components, thereby achieving effects such as moisture retention and aroma enhancement.

[0086] As can be seen from the comparison between Example 1 and Comparative Example 3, the reconstituted tobacco produced by adding mesoporous graphene framework material to tobacco leaves has good moisture retention and heat uniformity. The reconstituted tobacco leaves are not prone to moisture absorption. The mesoporous graphene framework material in the reconstituted tobacco leaves has abundant pore structure and specific surface area, which can regulate the slow release of moisture and the release of smoke, thereby achieving the effects of moisture retention and aroma enhancement.

[0087] During the preparation of reconstituted tobacco leaves as described in Examples 1-4, HRTEM images of two-dimensional graphene-like frameworks (MGFs) were obtained as follows: Figure 1-4 As shown, by Figure 1-4 It can be seen that at very low temperatures, the internal lattice fringes are relatively blurry, indicating the presence of a large number of amorphous carbon species. As the graphitization temperature gradually increases, the layered lattice fringes become clearer, thus indicating that the amorphous carbon species continuously crystallize at high temperatures.

[0088] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for preparing reconstituted tobacco leaves, characterized in that, The preparation method includes the following steps: (1) After mixing metal oleate, template agent, surfactant and solvent, the mixture is subjected to pyrolysis to obtain solid material, and the solid material is subjected to calcination to obtain supercrystalline metal oxide; (2) After etching the supercrystalline metal oxide, the etched material is graphitized to obtain a mesoporous graphene framework material. (3) The mesoporous graphene framework material, tobacco raw material, adhesive and additives are mixed and then post-processed to obtain the reconstituted tobacco. The metal oleate in step (1) includes any one or a combination of at least two of iron oleate, nickel oleate, cobalt oleate or manganese oleate, and the surfactant includes sodium oleate. The mass ratio of the surfactant to the metal oleate is 1:(5~15). The graphitization treatment in step (2) is carried out at a temperature of 900~1600℃ and for a time of 1~3h. The mass ratio of the mesoporous graphene framework material, tobacco raw material, adhesive and additives in step (3) is (1~5):100:(1~5):(30~50).

2. The preparation method according to claim 1, characterized in that, The template agent in step (1) includes sodium chloride particles.

3. The preparation method according to claim 1, characterized in that, The solvent in step (1) includes n-hexane.

4. The preparation method according to claim 1, characterized in that, The solid-liquid ratio of the metal oleate to the solvent in step (1) is 0.3~0.5 g / mL.

5. The preparation method according to claim 1, characterized in that, The mass ratio of the metal oleate to the template agent in step (1) is 1:(5~15).

6. The preparation method according to claim 1, characterized in that, The temperature of the pyrolysis treatment in step (1) is 300~500℃.

7. The preparation method according to claim 1, characterized in that, The pyrolysis treatment in step (1) takes 1 to 3 hours.

8. The preparation method according to claim 1, characterized in that, After the pyrolysis treatment in step (1), the process involves cooling, washing, and drying.

9. The preparation method according to claim 8, characterized in that, The detergent used in the washing process includes deionized water.

10. The preparation method according to claim 1, characterized in that, The calcination temperature in step (1) is 550~650℃.

11. The preparation method according to claim 1, characterized in that, The calcination process in step (1) takes 1 to 3 hours.

12. The preparation method according to claim 1, characterized in that, The etching process in step (2) includes the following steps: The supercrystalline metal oxide was mixed with ultrapure water and then hydrochloric acid was added. After the reaction, the solution was removed by filtration to obtain a black solid powder. The above steps were repeated until the solution obtained by filtration did not change color, thus obtaining the etching material.

13. The preparation method according to claim 12, characterized in that, The reaction time is 0.5~1.5h.

14. The preparation method according to claim 1, characterized in that, The adhesive in step (3) includes sodium carboxymethyl cellulose.

15. The preparation method according to claim 1, characterized in that, The additives mentioned in step (3) include glycerol and / or propylene glycol.

16. The preparation method according to claim 1, characterized in that, The post-processing in step (3) includes centrifugation, rolling and drying.

17. A reconstituted tobacco leaf, characterized in that, The reconstituted tobacco leaves are obtained by the method described in any one of claims 1-16.

18. A tobacco product, characterized in that, The tobacco product comprises reconstituted tobacco as described in claim 17.

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