阅读说明：本技术 一种彰显中式卷烟甜味特性的香原料的制备方法及应用 (Preparation method and application of fragrant raw material for showing sweet taste characteristics of Chinese-style cigarettes ) 是由 马宇平 陈芝飞 席高磊 王清福 马胜涛 刘强 蔡莉莉 赵旭 赵志伟 于 2020-12-10 设计创作，主要内容包括：本发明涉及一种彰显中式卷烟甜味特性的香原料的制备方法及应用。通过乙基麦芽酚发生乙酰化反应得到乙基麦芽酚乙酸酯,然后氢化还原得到二氢乙基麦芽酚乙酸酯,再与乙酰氧化试剂反应得到二氢乙基麦芽酚二乙酸酯,最后利用脂肪酶水解得到2,3-二氢-3,5-二羟基-6-乙基-4H-吡喃-4-酮。与现有技术相比,本发明反应收率显著提升,而且本技术反应工艺操作简便,能够进行大规模生产,具有广泛的应用前景。该香原料添加至卷烟中可以丰富烟香,增加烟气透发性和细腻程度,改善余味舒适性,增加口腔甜润感,进而彰显中式卷烟“甜味”特征,具有潜在应用价值。(The invention relates to a preparation method and application of a fragrant raw material for showing the sweet taste characteristic of Chinese cigarettes. Ethyl maltol is subjected to acetylation reaction to obtain ethyl maltol acetate, then the ethyl maltol acetate is subjected to hydrogenation reduction to obtain dihydro ethyl maltol acetate, the dihydro ethyl maltol acetate reacts with an acetyl oxidation reagent to obtain dihydro ethyl maltol diacetate, and finally the dihydro ethyl maltol diacetate is hydrolyzed by using lipase to obtain 2, 3-dihydro-3, 5-dihydroxy-6-ethyl-4H-pyran-4-one. Compared with the prior art, the method has the advantages that the reaction yield is obviously improved, the reaction process is simple and convenient to operate, large-scale production can be realized, and the method has a wide application prospect. The cigarette flavor raw material is added into the cigarette, so that the cigarette flavor can be enriched, the smoke penetrability and the fineness are increased, the aftertaste comfort is improved, the sweet feeling in the oral cavity is increased, the 'sweet' characteristic of the Chinese cigarette is revealed, and the cigarette flavor has potential application value.)

1. A preparation method of a fragrant raw material for showing the sweet taste characteristic of Chinese cigarettes is disclosed, wherein the fragrant raw material is 2, 3-dihydro-3, 5-dihydroxy-6-ethyl-4H-pyran-4-one, and is characterized by comprising the following preparation steps:

1) preparing ethyl maltol acetate I from ethyl maltol;

2) preparing dihydroethyl maltol acetate II from ethyl maltol acetate I;

3) preparing dihydro ethyl maltol diacetate III from dihydro ethyl maltol acetate II;

4) preparing 2, 3-dihydro-3, 5-dihydroxy-6-ethyl-4H-pyran-4-one from dihydro ethyl maltol diacetate III;

the preparation method of the structural formula comprises the following steps:

2. the preparation method of the fragrant raw material for revealing the sweet taste characteristic of the Chinese style cigarette according to claim 1, which is characterized by comprising the following specific preparation steps:

(1) ethyl maltol acetate I preparation: sequentially adding ethyl maltol and an acetylation reagent into a reaction bottle, reacting for 4-6 h at 60-120 ℃, adding ethyl acetate into the reaction liquid for dilution, adding a saturated sodium bicarbonate solution in batches under stirring until no bubbles are generated, washing an organic phase with a saturated NaCl solution, separating an organic layer, and using anhydrous Na for removing the organic layer₂SO₄Drying, and evaporating under reduced pressure to remove the solvent to obtain a light yellow oily substance ethyl maltol acetate I;

(2) preparation of dihydroethyl maltol acetate II: dissolving ethyl maltol acetate I in ethyl acetate, adding a hydrogenation catalyst, reacting at room temperature for 4-6 hours in a hydrogen atmosphere, performing suction filtration after the reaction is finished, and performing reduced pressure concentration on the filtrate to obtain dihydro ethyl maltol acetate II;

(3) preparation of Dihydroethyl maltol diacetate III: in a reaction bottle, adding dihydroethyl maltol acetate II and ethylReacting an acyl oxidation reagent and a solvent at 60-120 ℃ for 10-12 h, cooling the reaction solution, washing with a saturated NaCl solution, separating an organic layer, and using anhydrous Na₂SO₄Drying, evaporating under reduced pressure to remove solvent, and performing silica gel column chromatography on the residue to obtain colorless oily substance dihydroethyl maltol diacetate III;

(4) preparation of 2, 3-dihydro-3, 5-dihydroxy-6-ethyl-4H-pyran-4-one: adding dihydro ethyl maltol diacetate III, lipase and solvent into a reaction bottle in sequence, reacting for 3 hours at 0-80 ℃, extracting an organic layer with dichloromethane, and adding anhydrous Na₂SO₄Drying, evaporating under reduced pressure to remove solvent, and performing silica gel column chromatography on the residue to obtain colorless oily substance 2, 3-dihydro-3, 5-dihydroxy-6-ethyl-4H-pyran-4-one.

3. The method for preparing a fragrant raw material for showing the sweet taste characteristic of Chinese cigarettes according to claim 2, wherein the acetylation reagent in the step (1) is one of acetic anhydride or acetyl chloride.

4. The method for preparing a fragrant raw material for showing the sweet taste of Chinese cigarettes according to claim 2, wherein the molar ratio of ethyl maltol to the acetylation reagent in the step (1) is 1: (1-3), the reaction temperature is 60-120 ℃.

5. The method for preparing a fragrant raw material showing the sweet taste characteristic of Chinese cigarettes according to claim 2, wherein the hydrogenation catalyst in the step (2) is one of palladium carbon, raney nickel and tris (triphenylphosphine) rhodium chloride; the mass ratio of the ethyl maltol acetate I to the hydrogenation catalyst is 1: (0.05-0.5).

6. The method for preparing a fragrant raw material for showing the sweet taste of Chinese cigarettes according to claim 2, wherein the acetoxidation reagent in the step (3) is one of lead tetraacetate, manganese triacetate and silver acetate, and the molar ratio of the dihydroethyl maltol acetate II to the acetoxidation reagent is 1: (0.5-3), wherein the reaction solvent is one of benzene, toluene or cyclohexane; the reaction temperature is 60-120 ℃.

7. The method for preparing a fragrant raw material for showing the sweet taste of Chinese cigarettes according to claim 2, wherein the lipase in the step (4) is one of candida rugosa lipase or porcine pancreatic lipase; the mass ratio of the dihydroethyl maltol diacetate III to the lipase is 1: (0.01 to 0.5); the reaction solvent is one of acetonitrile, toluene or water; the reaction temperature is 0-80 ℃.

8. Use of a flavor material for revealing the sweetness characteristic of a chinese cigarette, characterized in that the flavor material of any one of the above claims 1 to 7 is used.

9. The use of the flavor raw material for developing the sweetness characteristic of a Chinese cigarette according to claim 8, wherein the alcoholic solution of the flavor raw material is sprayed on the cut tobacco.

10. The application of the fragrant raw material for showing the sweet taste characteristic of Chinese cigarettes according to claim 9, wherein the adding amount of the fragrant raw material is 1-50 ppm of the mass of the cut tobacco.

Technical Field

The invention belongs to the technical field of synthesis of cigarette flavor raw materials, and particularly relates to a preparation method of a flavor raw material 2, 3-dihydro-3, 5-dihydroxy-6-ethyl-4H-pyran-4-one which shows the sweet taste characteristic of a Chinese cigarette and application of the flavor raw material as a flavor raw material in cigarettes.

Background

The 'sweet taste' of smoke is a key index influencing the sensory quality and the style characteristics of cigarettes, and is one of important marks of Chinese cigarettes which are different from American, English, Japanese and the like cigarettes. In order to show the characteristics, substances such as saccharides, extractum, Maillard reactants and the like are generally used in the flavoring of Chinese style cigarettes; these substances can generate sweet taste in smoke, mainly because they contain or crack to generate volatile sweet substances such as pyrones and dehydrated saccharides, but because the content of these sweet substances is very low, the cigarette 'sweet taste' characteristics are not good. Therefore, the volatile sweet substances are directly used as the fragrant raw materials, so that the content of the sweet substances in the smoke can be obviously improved, and the 'sweet taste' characteristic of the Chinese cigarette is effectively displayed.

2, 3-dihydro-3, 5-dihydroxy-6-ethyl-4H-pyran-4-ketone (DDMP) belongs to pyranol enol ketone compounds, and when the DDMP is added into cigarettes, the sweet taste of cigarette smoke can be obviously improved, the taste characteristics of sweetness and moistness of the cigarettes are highlighted, and the DDMP is in positive correlation with the sweetness of the smoke. The synthesis and application research of 2, 3-dihydro-3, 5-dihydroxy-6-ethyl-4H-pyran-4-one is reported at home and abroad. Therefore, the development of the synthesis of the 2, 3-dihydro-3, 5-dihydroxy-6-ethyl-4H-pyran-4-one and the application research thereof in cigarettes has important significance for showing the 'sweet taste' style characteristic of Chinese cigarettes.

Disclosure of Invention

The invention aims to provide a preparation method of 2, 3-dihydro-3, 5-dihydroxy-6-ethyl-4H-pyran-4-one serving as a fragrant raw material which is simple to operate, high in yield and easy to produce in a large scale and shows the sweet taste characteristic of Chinese cigarettes, and application of the fragrant raw material in cigarettes.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

a preparation method of a fragrant raw material for showing the sweet taste characteristic of Chinese cigarettes, wherein the fragrant raw material is 2, 3-dihydro-3, 5-dihydroxy-6-ethyl-4H-pyran-4-one, comprises the following preparation steps:

1) preparing ethyl maltol acetate I from ethyl maltol;

2) preparing dihydroethyl maltol acetate II from ethyl maltol acetate I;

3) preparing dihydro ethyl maltol diacetate III from dihydro ethyl maltol acetate II;

4) preparing 2, 3-dihydro-3, 5-dihydroxy-6-ethyl-4H-pyran-4-one from dihydro ethyl maltol diacetate III;

the preparation method of the structural formula comprises the following steps:

the preparation method comprises the following specific steps:

(1) ethyl maltol acetate I preparation: sequentially adding ethyl maltol and an acetylation reagent into a reaction bottle, reacting for 4-6 h at 60-120 ℃, adding ethyl acetate into the reaction liquid for dilution, adding a saturated sodium bicarbonate solution in batches under stirring until no bubbles are generated, washing an organic phase with a saturated NaCl solution, separating an organic layer, and using anhydrous Na for removing the organic layer₂SO₄Drying, and evaporating under reduced pressure to remove the solvent to obtain a light yellow oily substance ethyl maltol acetate I;

(2) preparation of dihydroethyl maltol acetate II: dissolving ethyl maltol acetate I in ethyl acetate, adding a hydrogenation catalyst, reacting at room temperature for 4-6 hours in a hydrogen atmosphere, performing suction filtration after the reaction is finished, and performing reduced pressure concentration on the filtrate to obtain dihydro ethyl maltol acetate II;

(3) preparation of Dihydroethyl maltol diacetate III: adding dihydro ethyl maltol acetate II, an acetyl oxidation reagent and a solvent into a reaction bottle in sequence, reacting for 10-12 h at 60-120 ℃, cooling the reaction liquid, washing with a saturated NaCl solution, separating an organic layer, and using anhydrous Na₂SO₄Drying, evaporating under reduced pressure to remove solvent, and performing silica gel column chromatography on the residue to obtain colorless oily substance dihydroethyl maltol diacetate III;

(4) preparation of 2, 3-dihydro-3, 5-dihydroxy-6-ethyl-4H-pyran-4-one: adding dihydro ethyl maltol diacetate III, lipase and solvent into a reaction bottle in sequence, reacting for 3 hours at 0-80 ℃, extracting an organic layer with dichloromethane, and adding anhydrous Na₂SO₄Drying, evaporating under reduced pressure to remove solvent, and performing silica gel column chromatography on the residue to obtain colorless oily substance 2, 3-dihydro-3, 5-dihydroxy-6-ethyl-4H-pyran-4-one (IV).

Further, the acetylation reagent in the step (1) is one of acetic anhydride or acetyl chloride.

Further, the molar ratio of the ethyl maltol to the acetylation reagent in the step (1) is 1: (1-3), the reaction temperature is 60-120 ℃.

Further, the hydrogenation catalyst in the step (2) is one of palladium carbon, raney nickel and tris (triphenylphosphine) rhodium chloride; the mass ratio of the ethyl maltol acetate I to the hydrogenation catalyst is 1: (0.05-0.5).

Further, in the step (3), the acetoxylation reagent is one of lead tetraacetate, manganese triacetate and silver acetate, and the molar ratio of the dihydroethyl maltol acetate II to the acetoxylation reagent is 1: (0.5-3), wherein the reaction solvent is one of benzene, toluene or cyclohexane; the reaction temperature is 60-120 ℃.

Further, the lipase in the step (4) is one of candida rugosa lipase or porcine pancreatic lipase; the mass ratio of the dihydroethyl maltol diacetate III to the lipase is 1: (0.01 to 0.5); the reaction solvent is one of acetonitrile, toluene or water; the reaction temperature is 0-80 ℃.

An application of a fragrant raw material for showing the sweet taste characteristic of Chinese cigarettes, wherein any one of the fragrant raw materials is applied to the cigarettes.

Preferably, the alcoholic solution of the fragrant raw material is sprayed on the cut tobacco.

Preferably, the addition amount of the flavor raw materials is 1-50 ppm of the mass of the cut tobacco.

The invention has the advantages that;

the technical scheme takes ethyl maltol as a starting material, and prepares the 2, 3-dihydro-3, 5-dihydroxy-6-ethyl-4H-pyran-4-one through four-step reaction synthesis, compared with the yield of the preparation method in the prior art, the method has the advantages that the reaction yield is obviously improved, the total yield is up to 79.4 percent, the reaction process is simple, the operation is simple and convenient, the large-scale production can be carried out, and the method has wide application prospect. The cigarette flavor raw material is added into the cigarette, so that the cigarette flavor can be enriched, the smoke penetrability and the fineness are increased, the aftertaste comfort is improved, the sweet feeling in the oral cavity is increased, the 'sweet' characteristic of the Chinese cigarette is revealed, and the cigarette flavor has potential application value.

Detailed Description

The technical solutions of the present invention are described in detail below by examples, and the following examples are only exemplary and can be used only for explaining and explaining the technical solutions of the present invention, but not construed as limiting the technical solutions of the present invention.

The specific preparation steps of the structural formula are as follows:

example 1

Preparation of ethyl maltol acetate: ethyl maltol (1.40g, 10mmol) and acetic anhydride (2.04g, 20mmol) were added in this order to a 50mL round bottom flask, and after 6 hours of reaction at 90 ℃, 100mL ethyl acetate was added to dilute the reaction solution, and a saturated sodium bicarbonate solution was added in portions with stirring until no more bubbles were formed, the organic phase was washed 2 times with a saturated NaCl solution, and the organic layer was separated and washed with anhydrous Na₂SO₄Drying, evaporating under reduced pressure to remove solvent to obtain light yellow oily substance 1.78g, yield 97.8%,the product ethyl maltol acetate can be directly used for the next reaction.

Preparation of Dihydroethyl maltol acetate: in a 100mL round-bottomed flask, ethyl maltol acetate (1.82g, 10mmol), 5% palladium on carbon (0.2g), ethyl acetate (20 mL) was charged into the round-bottomed flask, and the mixture was purged with nitrogen and hydrogen 3 times, followed by reaction at room temperature under a hydrogen atmosphere for 3 hours (as monitored by TLC, the reaction was stopped immediately after completion of the reaction of the starting material). The reaction mixture was filtered with suction, the solvent was evaporated under reduced pressure, and the residue was subjected to silica gel column chromatography and eluted with petroleum ether/ethyl acetate 3/1 to give dihydroethyl maltol acetate 1.75g as a colorless oil in 92.4% yield.

Preparation of Dihydroethyl maltol diacetate: in a 100mL round bottom flask, dihydroethyl maltol acetate (1.84g, 10mmol) was dissolved in 20mL dry toluene, purged with nitrogen for 10min to remove oxygen, and then lead tetraacetate (8.86g, 20mmol) was added and reacted at 100 ℃ for 12 h. After the reaction solution was cooled, it was washed with saturated NaCl solution 2 times, and the organic layer was separated and Na anhydrous₂SO₄The mixture was dried, the solvent was distilled off under reduced pressure, and the residue was subjected to silica gel column chromatography, eluting with methylene chloride/ethyl acetate 50/1, to give dihydroethyl maltol diacetate 2.22g as a colorless oil in 91.7% yield.

Preparation of 2, 3-dihydro-3, 5-dihydroxy-6-ethyl-4H-pyran-4-one: dihydroethyl maltol diacetate (1.09g, 4.5mmol) was dissolved in 20mL of water, 50mg of Candida rugosa lipase (Candida rugosa) was added, the reaction was carried out at room temperature for 3 hours, the aqueous phase was extracted with dichloromethane 3 times, the organic layers were combined, and Na anhydrous₂SO₄Drying, removing the solvent by evaporation under reduced pressure, and performing silica gel column chromatography on the residue to obtain 0.68g of colorless oily substance 2, 3-dihydro-3, 5-dihydroxy-6-ethyl-4H-pyran-4-one, wherein the yield is 95.8 percent, and the total yield of the four steps is 79.4 percent.

Example 2

Preparation of ethyl maltol acetate: ethyl maltol (1.40g, 10mmol) and acetyl chloride (1.57g, 20mmol) were added sequentially to a 50mL round-bottomed flask, and after 6 hours of reaction at 90 ℃, 100mL of ethyl acetate was added to dilute the reaction solution, and a saturated sodium bicarbonate solution was added in portions with stirring until no more bubbles were formed. Using the organic phaseWashing with saturated NaCl solution for 2 times, separating organic layer, and adding anhydrous Na₂SO₄Drying, and distilling off the solvent under reduced pressure to obtain 1.64g of ethyl maltol acetate as a light yellow oily substance, wherein the yield is 90.1%, and the ethyl maltol acetate can be directly subjected to the next reaction.

Preparation of Dihydroethyl maltol acetate: in a 100mL round-bottom flask, ethyl maltol acetate (1.82g, 10mmol), Raney nickel (0.2g), ethyl acetate (20 mL) were charged into the round-bottom flask, and the mixture was reacted under a hydrogen atmosphere for 3 hours (TLC monitoring, starting materials were immediately reacted and stopped). The reaction mixture was filtered with suction, the solvent was evaporated under reduced pressure, and the residue was subjected to silica gel column chromatography and eluted with petroleum ether/ethyl acetate 3/1 to give 1.48g of dihydroethyl maltol acetate as a colorless oil in 80.4% yield.

Preparation of Dihydroethyl maltol diacetate: in a 100mL round bottom flask, Dihydroethyl maltol acetate (1.84g, 10mmol) was dissolved in 20mL dry toluene, purged with nitrogen for 10min to remove oxygen, and then silver acetate (3.34g, 20mmol) was added and reacted at 100 ℃ for 12 h. After the reaction solution was cooled, it was washed with saturated NaCl solution 2 times, and the organic layer was separated and Na anhydrous₂SO₄The mixture was dried, the solvent was distilled off under reduced pressure, and the residue was subjected to silica gel column chromatography, eluting with methylene chloride/ethyl acetate 50/1, to give 1.99g of dihydroethyl maltol diacetate as a colorless oil in 82.2% yield.

Preparation of 2, 3-dihydro-3, 5-dihydroxy-6-ethyl-4H-pyran-4-one: dissolving Dihydroethyl maltol diacetate (1.09g, 4.5mmol) in 20mL of toluene, adding 50mg of Candida rugosa lipase, reacting at 50 deg.C for 3h, extracting the aqueous phase with dichloromethane for 3 times, combining the organic layers, and adding anhydrous Na₂SO₄Drying, removing the solvent by evaporation under reduced pressure, and subjecting the residue to silica gel column chromatography to give 2, 3-dihydro-3, 5-dihydroxy-6-ethyl-4H-pyran-4-one as a colorless oil 0.58g, in 81.7% yield. The total yield of the four-step reaction is calculated to be 48.6 percent.

Example 3

Preparation of ethyl maltol acetate: in a 50mL round bottom flask, ethyl maltol (1.40g, 10mmol) and acetic anhydride (1.02g, 10mmol) were added sequentiallymmol) at 90 deg.C for 6h, reacting at 90 deg.C for 6h, diluting the reaction solution with 100mL ethyl acetate, and adding saturated sodium bicarbonate solution in portions while stirring until no bubbles are formed. The organic phase was washed 2 times with saturated NaCl solution, the organic layer was separated and washed with anhydrous Na₂SO₄Drying, and distilling off the solvent under reduced pressure to obtain 1.62g of ethyl maltol acetate as a light yellow oily substance with the yield of 89.0%, wherein the ethyl maltol acetate can be directly subjected to the next reaction.

Preparation of Dihydroethyl maltol acetate: in a 100mL round-bottom flask, ethyl maltol acetate (1.82g, 10mmol), tris (triphenylphosphine) rhodium chloride (0.2g), ethyl acetate (20 mL), 3 times with nitrogen and 3 times with hydrogen, respectively, were added, followed by reaction under hydrogen atmosphere for 3 hours (TLC monitoring, starting material reaction was stopped immediately after completion). The reaction mixture was filtered with suction, the solvent was evaporated under reduced pressure, and the residue was subjected to silica gel column chromatography and eluted with petroleum ether/ethyl acetate 3/1 to give 1.51g of dihydroethyl maltol acetate as a colorless oil in 82.1% yield.

Preparation of Dihydroethyl maltol diacetate: in a 100mL round bottom flask, dihydro ethyl maltol acetate (1.84g, 10mmol) was dissolved in 20mL of anhydrous toluene, purged with nitrogen for 10min to remove oxygen, and then manganese triacetate (5.36g, 20mmol) was added and reacted at 100 ℃ for 12 h. After the reaction solution was cooled, it was washed with saturated NaCl solution 2 times, and the organic layer was separated and Na anhydrous₂SO₄The mixture was dried, the solvent was distilled off under reduced pressure, and the residue was subjected to silica gel column chromatography, eluting with methylene chloride/ethyl acetate 50/1, to give dihydroethyl maltol diacetate 1.91g as a colorless oil in 78.9% yield.

Preparation of 2, 3-dihydro-3, 5-dihydroxy-6-ethyl-4H-pyran-4-one: dihydroethyl maltol diacetate (1.09g, 4.5mmol) was dissolved in 20mL acetonitrile, 50mg of porcine pancreatic lipase was added, the reaction was carried out at room temperature for 3 hours, the aqueous phase was extracted with dichloromethane 3 times, the organic layers were combined, and anhydrous Na was added₂SO₄Drying, removing solvent by evaporation under reduced pressure, and performing silica gel column chromatography on the residue to obtain colorless oil 0.55g, the yield is 77.5%, and the total yield of the four-step reaction is 44.7%.

Testing the performance of the incense raw materials:

an amount of 2, 3-dihydro-3, 5-dihydroxy-6-ethyl-4H-pyran-4-one (DDMP) prepared in any of the above examples was weighed and diluted with ethanol to a 5% solution for use. Weighing 100g of blank cigarette tobacco without flavoring, evenly spreading the blank cigarette tobacco in a clean tray, evenly spraying an ethanol solution of 2, 3-dihydro-3, 5-dihydroxy-6-ethyl-4H-pyran-4-one on the tobacco to prepare flavored tobacco with the proportion of 2, 3-dihydro-3, 5-dihydroxy-6-ethyl-4H-pyran-4-one to the tobacco of 1ppm, 5ppm, 10ppm, 20ppm, 30ppm and 50ppm, sealing and placing for 4H, placing in a 50 ℃ oven for drying, humidifying to standard moisture (12%) with distilled water, rolling into standard cigarettes, balancing the moisture (the humidity is 60% +/-2%, and the temperature is 22 +/-1 ℃) for 48H, and then evaluating the smoking. The control sample was a blank cigarette and the control sample was equilibrated for 48h under the same temperature and humidity conditions.

TABLE 1 perfuming test results

As can be seen from Table 1: the 2, 3-dihydro-3, 5-dihydroxy-6-ethyl-4H-pyran-4-ketone (fragrant raw material) has the functions of obviously improving and modifying the fragrance of cigarettes, reducing irritation, improving smoking taste and making the aftertaste clean and comfortable. The cigarette has prominent 'sweet' in taste sense, has the characteristic of remarkably improving 'sweet back' of cigarette smoke, and highlights the taste characteristics of 'sweet' and 'moist' of the cigarette. However, when the amount is 50ppm, scorching smell is generated, the cigarette fragrance quality is reduced, discomfort is generated, and the aftertaste is deteriorated, the recommended amount is: 20 to 30 ppm.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.