Tobacco humectant, preparation method and use thereof

Abstract

A tobacco humectant, which is a metal-organic framework material with a three-dimensional structure obtained by a self-assembly of Zr.sup.4+ and terephthalic acid or 2-aminoterephthalic acid. The metal-organic framework material with the three-dimensional structure obtained by the self-assembly of the Zr.sup.4+ and the terephthalic acid is Uio-66, and the metal-organic framework material with the three-dimensional structure obtained by the self-assembly of the Zr.sup.4+ and the 2-aminoterephthalic acid is Uio-66-NH.sub.2. A preparation method of the tobacco humectant and a use thereof in tobacco is further provided.

Claims

1. A method of preparing tobacco, comprising the step of using a tobacco humectant as an additive material in the tobacco, wherein, the tobacco humectant is a metal-organic framework material with a three-dimensional structure obtained by a self-assembly of Zr.sup.4+ and terephthalic acid or 2-aminoterephthalic acid; the metal-organic framework material with the three-dimensional structure obtained by the self-assembly of the Zr.sup.4+ and the terephthalic acid is Uio-66, and the metal-organic framework material with the three-dimensional structure obtained by the self-assembly of the Zr.sup.4+ and the 2-aminoterephthalic acid is Uio-66-NH.sub.2.

2. The method according to claim 1, wherein, the tobacco humectant is used in an amount ranging from 0.05% to 1.0% by weight of the tobacco.

3. The method according to claim 1, wherein, the Uio-66 has a molecular formula of Zr.sub.24O.sub.120C.sub.192H.sub.96, a molecular weight of 6512.10, a space group of Fm3m of a cubic system, wherein a=b=c=20.7004 Å; and the Uio-66-NH.sub.2 has a molecular formula of Zr.sub.24O.sub.120C.sub.192H.sub.144N.sub.24, a molecular weight of 6560.1, a space group of Fm3m of a cubic system, wherein a=b=c=20.4832 Å.

4. The method according to claim 2, wherein, the Uio-66 has a molecular formula of Zr.sub.24O.sub.120C.sub.192H.sub.96, a molecular weight of 6512.10, a space group of Fm3m of a cubic system, wherein a=b=c=20.7004 Å; and the Uio-66-NH.sub.2 has a molecular formula of Zr.sub.24O.sub.120C.sub.192H.sub.144N.sub.24, a molecular weight of 6560.1, a space group of Fm3m of a cubic system, wherein a=b=c=20.4832 Å.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic diagram showing a three-dimensional structure of a tobacco humectant Uio-66 of the present invention.

(2) FIG. 2 is a schematic diagram showing a three-dimensional structure of a tobacco humectant Uio-66-NH.sub.2 of the present invention.

(3) FIG. 3 is a diagram showing a powder X-ray diffraction (PXRD) of tobacco humectants Uio-66 and Uio-66-NH.sub.2 of the present invention.

(4) FIG. 4 is a diagram showing a result of a dynamic vapor sorption analysis of a tobacco humectant Uio-66 of the present invention.

(5) FIG. 5 is a diagram showing a result of a dynamic vapor sorption analysis of a tobacco humectant Uio-66-NH.sub.2 of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

(6) The present invention is further described in detail below with reference to the specific embodiments. It should be noted that the specific embodiments are only the preferred embodiments of the present invention, and are not intended to limit the scope of the present invention, that is, all equivalent changes and modifications made according to the scope of the present application should still be within the protective scope of the present invention.

Embodiment 1

(7) Preparation of Tobacco Humectant Uio-66 by Solvothermal Method:

(8) 15 mmol of anhydrous ZrCl.sub.4 was placed in a beaker, and 30 mL of N,N′-dimethylformamide was added, followed by a sonication for 30 minutes until complete dissolution. 15 mmol of terephthalic acid and 60 mL of N,N′-dimethylformamide were added to the above solution, and the sonication was continued for 30 minutes until complete dissolution. The above mixed solution was transferred to a polytetrafluoroethylene reactor for a reaction at 120° C. for 24 hours. A first solid product was filtered out, washed with 20 mL of ethanol at 60° C., dried and transferred to a conical flask. 30 mL of N,N′-dimethylformamide was added, and stirring was performed to remove the unreacted ligand. The above product was filtered out, washed with 20 mL of ethanol, dried and transferred to the reactor, followed by drying in an oven at 90° C. for 12 hours. A second solid product was obtained by a centrifugation, then washed and centrifuged twice with 20 mL of ethanol, and washed and centrifuged twice with 20 mL of acetone, and then the solid was dried. The final product was placed in a reaction dish and dried under vacuum for 12 hours to obtain the tobacco humectant Uio-66. The three-dimensional structure of the obtained tobacco humectant Uio-66 is shown in FIG. 1. As can be seen from the FIG. 1, the obtained tobacco humectant Uio-66 has a relatively large specific surface area and an obvious pore structure. The prepared Uio-66 was determined to have a molecular formula of Zr.sub.24O.sub.120C.sub.192H.sub.96, a molecular weight of 6512.10, a space group of Fm3m of a cubic system, wherein a=b=c=20.7004 Å.

Embodiment 2

(9) Preparation of Tobacco Humectant Uio-66-NH.sub.2 by Solvothermal Method

(10) 18 mmol of anhydrous ZrCl.sub.4 was placed in a beaker, and 30 mL of N,N′-dimethylformamide was added, followed by a sonication for 30 minutes until complete dissolution. 14 mmol of 2-aminoterephthalic acid and 50 mL of N,N′-dimethylformamide were added to the above solution, and the sonication was continued for 30 minutes. The above mixed solution was transferred to a polytetrafluoroethylene reactor for a reaction at 120° C. for 24 hours. A first solid product was filtered out, washed with 20 mL of ethanol at 60° C., dried and transferred to a conical flask, 30 mL of N,N′-dimethylformamide was added, and stirring was performed to remove the unreacted ligand. The above product was filtered out, washed with 20 mL of ethanol, dried and transferred to a reactor, followed by drying in an oven at 90° C. for 12 hours. A second solid product was obtained by a centrifugation, then washed and centrifuged twice with 20 mL of ethanol, and washed and centrifuged twice with 20 mL of acetone, and then the solid was dried. The final product was placed in a reaction dish and dried under vacuum for 12 hours to obtain the tobacco humectant Uio-66-NH.sub.2. The three-dimensional structure of the obtained tobacco humectant Uio-66-NH.sub.2 is shown in FIG. 2. As can be seen from the FIG. 2, the obtained tobacco humectant Uio-66-NH.sub.2 has a relatively large specific surface area and an obvious pore structure. The prepared Uio-66-NH.sub.2 was determined to have a molecular formula of Zr.sub.24O.sub.120C.sub.192H.sub.144N.sub.24, a molecular weight of 6560.1, and a space group of Fm3m of a cubic system, wherein a=b=c=20.4832 Å.

(11) The powder X-ray diffraction (PXRD) pattern of the obtained tobacco humectants Uio-66 and Uio-66-NH.sub.2 is shown in FIG. 3. As can be seen from FIG. 3, the Uio-66 and Uio-66-NH.sub.2 obtained are relatively pure.

Embodiment 3

(12) Determination of Dynamic Changes in Moisture Content of Tobacco Added with Tobacco Humectant Uio-66

(13) The tobacco humectant Uio-66 prepared in Embodiment 1 was dissolved in a mixed solvent of 1,2-propylene glycol and glycerin, and added to the shredded tobacco according to 0.2% of the amount of the humectant by weight, and a shredded tobacco sample containing an equal amount of the alcohol mixed solvent without the humectant Uio-66 was used as a blank control. The shredded tobacco samples were then placed in a dynamic vapor sorption (DVS) apparatus at a temperature of 22° C. and a relative humidity of RH46% to determine the moisture dynamic content. The results are shown in Table 1 and FIG. 4. As can be seen from FIG. 4, the adsorption-desorption curve of the Uio-66 has a relatively large sorption hysteresis, and under certain pressure, the Uio-66 has a certain moisture adsorption-retention capability with a maximum adsorption amount of up to 14%, showing a good moisture adsorption capacity.

Embodiment 4

(14) Determination of Dynamic Moisture Content of Tobacco Added with Tobacco Humectant Uio-66-NH.sub.2

(15) The Uio-66-NH.sub.2 prepared in Embodiment 2 was dissolved in a mixed solvent of 1,2-propylene glycol and glycerin, and added to the shredded tobacco according to 0.2% of the amount of the humectant by weight, and a shredded tobacco sample containing an equal amount of the alcohol mixed solvent was used as a blank control. The shredded tobacco samples were then placed in a dynamic vapor sorption (DVS) apparatus at a temperature of 22° C. and a relative humidity of RH46% to determine the moisture dynamic content. The results are shown in Table 1 and FIG. 5. As can be seen from FIG. 5, the adsorption-desorption curve of the Uio-66-NH.sub.2 has a good sorption hysteresis, and under certain pressure, the Uio-66-NH.sub.2 has a certain moisture adsorption-retention capability with a maximum adsorption amount of up to 3.5%, showing a good moisture adsorption capacity.

(16) Table 1 shows a comparison of the moisture adsorption/desorption changes among the tobacco humectant Uio-66 and, the tobacco humectant Uio-66-NH.sub.2 and the equivalent alcohol mixed solvent in tobaccos.

(17) TABLE-US-00001 TABLE 1 Comparison of moisture adsorption/desorption changes among Uio-66, Uio-66-NH.sub.2 and propylene glycol Sorption hysteresis degree Equivalent alcohol mixed % P/P.sub.0 Uio-66 Uio-66-NH.sub.2 solvent 10.0 6.12 2.714 0.956 20.0 10.40 2.403 1.052 30.0 11.93 2.051 1.099 40.0 9.99 1.805 1.117 50.0 5.75 1.556 1.174 60.0 2.06 1.303 1.352

(18) The adsorption hysteresis degree in Table 1 indicates a moisture adsorption-retention capability at a certain pressure. As can be seen from Table 1, the adsorption hysteresis degrees of the Uio-66 and the Uio-66-NH.sub.2 are significantly larger than that of the equivalent alcohol mixed solvent, indicating that the Uio-66 and the Uio-66-NH.sub.2 have a strong moisture retention capability. Meanwhile, under each set humidity, the values of the adsorption hysteresis degrees of the Uio-66 and the Uio-66-NH.sub.2 are greater than that of the equivalent alcohol mixed solvent, indicating that the moisture content retention and moisturizing capabilities of the Uio-66 and the Uio-66-NH.sub.2 are better than that of the control group of the equivalent alcohol mixed solvent. Adding the Uio-66 or the Uio-66-NH.sub.2 to the tobacco helps to maintain the moisture content of the cigarettes, and increases the humidity and comfort level of the cigarette smoke, which brings a great practical significance in tobacco moisturizing.

Embodiment 5

(19) Sensory Evaluation of Cigarette after Adding Tobacco Humectant Uio-66

(20) The tobacco humectant Uio-66 was uniformly mixed in the shredded tobacco at 1% of the dry weight of the shredded tobacco. The control sample was the same quality of shredded tobacco without the Uio-66. The tobacco samples were placed in a constant temperature and humidity chamber with a humidity of 60±3% and a temperature of 22±1° C. for 48 hours. After manual rolling, the sensory evaluation was performed by organized professional assessment staffs according to GB5606.4-2005. The sensory evaluation results showed that the cigarette containing the humectant Uio-66 had a better taste, a stronger sweetness, a better flavor, and a better smoking comfort.

Embodiment 6

(21) Sensory Evaluation of Cigarette after Adding Tobacco Humectant Uio-66-NH.sub.2

(22) The tobacco humectant Uio-66-NH.sub.2 was uniformly mixed in the shredded tobacco at 1% of the dry weight of the shredded tobacco. The control sample was the same quality of shredded tobacco without the Uio-66-NH.sub.2. The tobacco samples were placed in a constant temperature and humidity chamber with a humidity of 60±3% and a temperature of 22±1° C. for 48 hours. After manual rolling, the sensory evaluation was performed by organized professional assessment staffs according to GB5606.4-2005. The results showed that the cigarette containing the humectant Uio-66-NH.sub.2 had a better taste, a enhanced sweetness, a less irritation, and a better smoking comfort.

Conclusion

(23) The results of the sensory evaluation in Embodiments 5 and 6 indicate that the tobacco humectants Uio-66 and Uio-66-NH.sub.2 obtained by the present invention can be added to tobacco, which can maintain the humidity of the tobacco, can bring the cigarette a sweet and moist sensory, and improve the comfort level of the cigarette smoke, and can be used as an additive material as a component in a formula of rolled tobacco leaves.

(24) The foregoing description is merely the basic description under the conception of the present invention. Any equivalent transformation made according to the technical solution of the present invention shall fall within the protective scope of the present invention.