Preparation method of a small molecule terpene fragrance substance

Abstract

The present invention relates to a preparation method of small molecule terpene flavor substances, belonging to the technical field of chemical engineering. The preparation method comprises the following steps: a macromolecular terpene compound, silver vanadate and a titanium silicate molecular sieve catalyst carry out a photocatalytic reaction in an oxidation environment to generate small molecule terpene flavor substances. The preparation method of the small molecule terpene flavor substances of the present invention combines photocatalytic C-C cleavage and oxidation catalysis, enabling the macromolecular terpene compound to generate small molecule terpene flavor substances. The conditions are mild, the process is controllable, the cost is low, and the catalytic materials such as silver vanadate and titanium silicate molecular sieve used are green and environmentally friendly and can be reused.

Description

Technical Field

[0001] The present invention relates to a preparation method of small - molecule terpene flavor substances, belonging to the field of chemical engineering technology. Background Art

[0002] Terpenoids are hydrocarbons composed of several isoprene structural units. According to the structure of terpenoids, they can be divided into monoterpenes (composed of two isoprene units), sesquiterpenes (composed of three isoprene units), diterpenes (composed of four isoprene units), sesterterpenes (composed of five isoprene units), triterpenes (composed of six isoprene units), tetraterpenes (composed of eight isoprene units), polyterpenes (composed of more than eight isoprene units), etc.

[0003] Small - molecule terpenoids such as monoterpenes and sesquiterpenes are mostly volatile oily liquids with special odors, which constitute the main components of plant essential oils and are important flavor substances. However, their extraction and preparation processes are complex, costly, and expensive. Their quality is limited by the planting environment and climate, and the controllability is poor. Macromolecular terpenoids such as solanesol (a terpene alcohol) and carotenoids (a terpene) are not easily volatile, are easily obtained, and are inexpensive. Moreover, they are endogenous components in tobacco. The small - molecule terpene flavor substances prepared by their degradation are harmonious with the tobacco flavor. After being added to cigarettes, they can significantly enrich the natural aroma of cigarette smoke. Macromolecular terpenoids, such as solanesol is a 4.5 - terpene alcohol and carotene is a 4 - terpene. They have large molecular weights and can produce rich terpene substances through catalytic cracking. However, the thermal cracking method has problems such as poor controllability and poor reproducibility. Therefore, developing a preparation method of terpene flavor substances with mild conditions and controllable processes has great potential value. Summary of the Invention

[0004] The purpose of the present invention is to provide a preparation method of small - molecule terpene flavor substances, which solves the problems of poor controllability and poor reproducibility in the prior art.

[0005] In order to achieve the above purpose, the technical solution adopted by the preparation method of small - molecule terpene flavor substances of the present invention is as follows:

[0006] A preparation method of small - molecule terpene flavor substances, comprising the following steps: Macromolecular terpenoid compounds, silver vanadate, and titanium - silicon molecular sieve catalyst carry out photocatalytic reaction in an oxidation environment to generate small - molecule terpene flavor substances.

[0007] The preparation method of small - molecule terpene flavor substances of the present invention combines photocatalytic C - C bond cleavage and oxidation catalysis to make macromolecular terpenoid compounds generate small - molecule terpene flavor substances. Its conditions are mild, the process is controllable, the cost is low, and the catalytic materials such as silver vanadate and titanium - silicon molecular sieve used are green and environmentally friendly and can be reused.

[0008] Preferably, the molar ratio of the macromolecular terpene compound to silver vanadate is 30-80:1. As a photocatalyst, silver vanadate can only cause the reaction of the macromolecular terpene compound under the condition of light irradiation.

[0009] To further catalyze the oxidation reaction, preferably, the mass ratio of the macromolecular terpene compound to the titanium silicalite molecular sieve is 200-300:1.

[0010] The titanium silicalite molecular sieve is divided into three-dimensional ordered hierarchical pore titanium silicalite molecular sieve and non-three-dimensional ordered hierarchical pore titanium silicalite molecular sieve. To make the degradation of the macromolecular terpene compound more complete, preferably, the titanium silicalite molecular sieve is a three-dimensional ordered hierarchical pore titanium silicalite molecular sieve.

[0011] Preferably, the photocatalytic reaction is carried out in an ionic liquid; the ionic liquid is a trihexyltetradecyl salt solution. As an ionic liquid solvent, the trihexyltetradecyl salt solution is green, environmentally friendly and reusable. Further preferably, the trihexyltetradecyl salt solution is one or any combination of trihexyltetradecyl bis(2,4,4-trimethylpentane) phosphite, trihexyltetradecyl chloride, and trihexyltetradecyl caprate.

[0012] Preferably, the macromolecular terpene compound is one or two of terpene compounds and terpenol compounds. Further preferably, the terpene compounds are one or any combination of β-carotene, squalene, and lutein; the terpenol compound is solanesol.

[0013] Preferably, the conditions of the photocatalytic reaction include light irradiation and heating.

[0014] Further preferably, the light irradiation condition is provided by a xenon lamp; the power of the xenon lamp is 35-55 W.

[0015] To promote the photocatalysis and oxidation reaction, preferably, the heating temperature is 100-200 °C and the time is 3-10 h.

[0016] Preferably, the oxidation environment is achieved by adding hydrogen peroxide to the system.

[0017] To better carry out the oxidation reaction, preferably, the mass fraction of hydrogen peroxide in the system is 0.5-1%. Description of the Drawings

[0018] Figure 1 It is the MS chromatogram of the distillate after photocatalysis of solanesol in Example 1;

[0019] Figure 2 It is the MS chromatogram of the distillate after photocatalysis of β-carotene in Example 2;

[0020] Figure 3MS chromatogram of the saponified distillate of squalene after photocatalysis in Example 3. Detailed implementation mode

[0021] The titanium silicalite molecular sieve of the present invention is prepared by mixing a tetrapropylammonium hydroxide solution and a sodium hydroxide solution to form a reaction solution, adding 3DOM Carbon (three-dimensional ordered macroporous carbon) to the reaction solution, drying, then adding tetraethyl orthosilicate and mixing evenly, adding tetrabutyl titanate after standing, placing it in a reaction kettle and heating to 130-220 °C, taking it out after 24-72 h and cooling it to room temperature, washing and drying, and then calcining it in an air atmosphere at 400-700 °C for 5-24 h.

[0022] Further, the tetrapropylammonium hydroxide solution is obtained by dissolving tetrapropylammonium hydroxide in absolute ethanol.

[0023] Further, the sodium hydroxide solution is obtained by dissolving sodium hydroxide in water.

[0024] Further, the material ratio of tetrapropylammonium hydroxide, sodium hydroxide, water and absolute ethanol in the reaction solution is (3-18):(0.1-0.3):(300-500):(150-300).

[0025] Further, the molar ratio of tetraethyl orthosilicate to tetrabutyl titanate is 10-100:1.

[0026] The technical solutions of the present invention will be further described below in conjunction with specific implementation modes.

[0027] I. Specific examples of the preparation method of the small molecule terpene fragrance substance of the present invention are as follows:

[0028] Example 1

[0029] The preparation method of the small molecule terpene fragrance substance in this example adopts the following steps:

[0030] (1) Ag 3 VO 4 Synthesis of photocatalyst: Weigh 0.5 g of AgNO 3 in a conical flask, add 25 mL of distilled water to dissolve it to obtain a clear and transparent solution A. Weigh 0.115 g of NH 4 VO 3 in a conical flask, add 25 mL of distilled water at 70 °C to dissolve it, and use 3 mol·L -1Adjust the pH value of the NaOH solution to 14 to obtain Solution B. Place Solution A in a separatory funnel and slowly drip it into Solution B in a conical flask while stirring magnetically, and yellow precipitate will form. After dripping, place the conical flask in a microwave oven and microwave heat it at 50% power for 1 h. Take out the conical flask from the microwave oven and stir magnetically at 30 °C for 0.5 h. Subsequently, centrifuge the precipitate, ultrasonically wash it 4 times with distilled water first, and finally ultrasonically wash it 1 time with absolute ethanol, and dry it in a constant temperature drying oven at 70 °C for more than 6 h to obtain the sample Ag 3 VO 4 powder.

[0031] (2) The three-dimensional ordered hierarchical porous titanium silicate molecular sieve (3DOM-TS) is prepared by the steam-assisted crystallization method (SAC): the molar ratio of tetrapropylammonium hydroxide (TPAOH): NaOH: H 2 O: EtOH in the reaction solution is 9: 0.15: 390: 180, where NaOH is dissolved in deionized water, and TPAOH and absolute ethanol are stirred and mixed. Put 0.20 g of 3DOM Carbon in a glass bottle, and then evenly drip the above reaction solution. Dry it at room temperature for more than 12 h. After the absolute ethanol has completely volatilized, drip 0.30 ml of TEOS (tetraethyl orthosilicate) and stir evenly. After standing for 12 h, add tetrabutyl titanate (TBOT) with a molar ratio of 1 / 10. Put it in a reaction kettle and heat it to 180 °C. After 48 h, take out the reaction kettle and cool it to room temperature. Wash the product with deionized water, dry it at 70 °C, and then calcine it in an air atmosphere at 550 °C for 12 h to remove the hard template and organic structure-directing agent to obtain the three-dimensional ordered hierarchical porous titanium silicate molecular sieve (3DOM-TS).

[0032] (3) Using solanesol as the target degradation product, add 100 g of solanesol to 500 mL of trihexyltetradecyl bis(2,4,4-trimethylpentane) phosphite ([P 66614 [Phos]) ionic liquid and dissolve it by ultrasonic treatment. Then add 0.5% H 2 O 2 and dissolve it by ultrasonic treatment. Then add 1 g of the synthesized Ag 3 VO 4 photocatalyst and 0.5 g of three-dimensional ordered hierarchical porous titanium silicate molecular sieve, and ultrasonically disperse for 15 min to make the solanesol reach the adsorption / desorption equilibrium on the catalyst surface. Use a 35 W xenon lamp (luminance: 3200 lm, color temperature: 6000 K) as the light source, stir magnetically and heat for 10 h, control the temperature at 200 °C. After the reaction is completed, perform vacuum distillation and collect the distillate. The MS chromatogram of the distillate is as Figure 1 shown, and the specific components and ratios are shown in Table 1.

[0033] Table 1 Composition and Proportion of Distillate

[0034]

[0035]

[0036] Example 2

[0037] The preparation method of small molecule terpene flavor substances in this example adopts the following steps:

[0038] (1) Synthesis of Ag 3 VO 4 photocatalyst: Weigh 0.1 g of AgNO 3 in a conical flask, add 10 mL of distilled water to dissolve it, and obtain a clear and transparent solution A. Weigh 2 times the molar ratio of AgNO 3 of NH 4 VO 3 in a conical flask, add distilled water at 70 °C to dissolve it, and adjust the pH value to 10 with 0.1 mol·L -1 NaOH solution to obtain solution B. Place solution A in a separatory funnel and slowly drip it into solution B in the conical flask while stirring magnetically, and yellow precipitate will form. After dripping, place the conical flask in a microwave oven and microwave-heat it at 20% power for 2 h. Take out the conical flask from the microwave oven and stir magnetically at 40 °C for 0.5 h. Then centrifuge the precipitate, wash it ultrasonically with distilled water 4 times first, and finally wash it ultrasonically with absolute ethanol 1 time, and dry it in a constant temperature drying oven at 70 °C for more than 6 h to obtain the sample Ag 3 VO 4 powder.

[0039] (2) Preparation of three-dimensional ordered hierarchical porous titanium silicate molecular sieve (3DOM-TS) by steam-assisted crystallization method (SAC): The reaction solution tetrapropylammonium hydroxide (TPAOH):NaOH:H 2The molar ratio of O:EtOH is 3:0.1:500:300, where NaOH is dissolved in deionized water, and TPAOH and absolute ethanol are stirred and mixed. Put 0.1 g of 3DOM Carbon in a glass bottle, then evenly dropwise add the above reaction solution, dry it at room temperature for more than 12 h. After the absolute ethanol has completely volatilized, dropwise add 0.1 mL of TEOS (tetraethyl orthosilicate) and stir evenly. After standing for 12 h, add tetrabutyl titanate (TBOT) with a molar ratio of 1 / 50, put it into a reaction kettle and heat it to 220 °C. After 24 h, take out the reaction kettle and cool it to room temperature. Wash the product with deionized water, dry it at 50 °C, and then calcine it in an air atmosphere at 400 °C for 24 h to remove the hard template and organic structure-directing agent to obtain three-dimensionally ordered hierarchical porous titanium silicate molecular sieve (3DOM-TS).

[0040] (3) Using β-carotene as the target degradation product, add 50 g of β-carotene to 300 mL of trihexyltetradecylammonium chloride ([P 66614 [C1]) ionic liquid and dissolve it by ultrasonic treatment, then add 1% of H 2 O 2 and dissolve it by ultrasonic treatment. Then add 0.4 g of the synthesized Ag 3 VO 4 photocatalyst and 0.2 g of three-dimensionally ordered hierarchical porous titanium silicate molecular sieve, disperse them by ultrasonic treatment for 20 min to make the adsorption / desorption equilibrium of β-carotene on the catalyst surface. Use a 35 W xenon lamp as the light source, stir magnetically and heat for 5 h, control the temperature at 150 °C. After the reaction is completed, perform vacuum distillation and collect the distillate. The MS chromatogram of the distillate is as Figure 2 shown, and the specific components and proportions are shown in Table 2.

[0041] Table 2 Components and Proportions of the Distillate

[0042] Number RT (min) Compound Ratio 1 13.149 Isophorone oxide 3.1％ 2 16.938 3-Hydroxy-ionone 15.1％ 3 22.189 β-Damascenone 6.7％ 4 25.901 3-Oxo-ionol 7.8％ 5 31.974 Norisoprenone 1 7.4％ 6 32.737 Norisoprenone 2 6.9％ 7 33.507 Norisoprenone 3 7.4％ 8 34.159 Norisoprenone 4 8.4％ 9 35.105 Norisoprenone 5 7.7％ 10 35.392 Octadiene 1.7％ 11 36.768 6-Methyl-5-hepten-2-one 12.7％

[0043] Example 3

[0044] The preparation method of the small molecule terpene fragrance substance in this example adopts the following steps:

[0045] (1) Synthesis of the Ag 3 VO 4 photocatalyst: Weigh 1 g of AgNO 3 and put it into a conical flask, add 50 mL of distilled water to dissolve it to obtain a clear and transparent solution A. Weigh NH 3 with a molar ratio 3 times that of AgNO 4 VO 3 and put it into a conical flask, add distilled water at 70 °C to dissolve it, and use 5 mol·L -1Adjust the pH value of the NaOH solution to 11 to obtain Solution B. Place Solution A in a separatory funnel and slowly add it dropwise to Solution B in a conical flask while stirring magnetically, and yellow precipitate will form. After dropping, place the conical flask in a microwave oven and microwave it at 80% power for 0.5 h. Take out the conical flask from the microwave oven and stir magnetically at 20 °C for 0.5 h. Subsequently, centrifuge the precipitate, ultrasonically wash it 4 times with distilled water first, and finally ultrasonically wash it 1 time with absolute ethanol, and dry it in a constant temperature drying oven at 70 °C for more than 6 h to obtain the sample Ag 3 VO 4 powder.

[0046] (2) The three-dimensional ordered hierarchical porous titanium silicate molecular sieve (3DOM-TS) is prepared by the steam-assisted crystallization method (SAC): the molar ratio of tetrapropylammonium hydroxide (TPAOH): NaOH: H 2 O: EtOH in the reaction solution is 18: 0.3: 300: 150, where NaOH is dissolved in deionized water, and TPAOH and absolute ethanol are stirred and mixed. Put 0.5 g of 3DOM Carbon in a glass bottle, then evenly drop the above reaction solution, dry it at room temperature for more than 12 h, wait for the absolute ethanol to volatilize completely, drop 0.6 mL of TEOS (tetraethyl orthosilicate) and stir evenly, after standing for 12 h, add tetrabutyl titanate (TBOT) with a molar ratio of 1 / 100, put it in a reaction kettle and heat it to 130 °C, take out the reaction kettle after 72 h and cool it to room temperature, wash the product with deionized water, dry it at 90 °C, and then calcine it in an air atmosphere at 700 °C for 5 h to remove the hard template and organic structure-directing agent to obtain the three-dimensional ordered hierarchical porous titanium silicate molecular sieve (3DOM-TS).

[0047] (3) Using squalene as the target degradation product, add 300 g of squalene to 500 mL of trihexyltetradecylphosphonium decanoate ([P 66614 [Dec]) ionic liquid and dissolve it by ultrasonic treatment, then add 1% of H 2 O 2 and dissolve it by ultrasonic treatment. Then add 2 g of the synthesized Ag 3 VO 4 photocatalyst and 1 g of three-dimensional ordered hierarchical porous titanium silicate molecular sieve, ultrasonically disperse for 10 min to make the adsorption / desorption equilibrium of squalene on the catalyst surface. Use a 35 W xenon lamp as the light source, stir magnetically and heat for 3 h, control the temperature at 100 °C. After the reaction, perform vacuum distillation and collect the distillate. The MS chromatogram of the distillate is as Figure 3 shown, and the specific components and ratios are shown in Table 3.

[0048] Table 3 Components and ratios of the distillate

[0049] Number RT (min) Compound Ratio 1 12.829 Limonene 0.7％ 2 20.539 Citral 0.7％ 3 22.216 Isovaleraldehyde 20.8％ 4 22.985 4-Methyl-2-butanone 12.8％ 5 23.833 Isopentanone 14.7％ 6 25.908 Geraniol 13.5％ 7 26.801 Linalool 9.8％ 8 28.425 Oxidized linalool 12.4％ 9 29.541 Neral 13.4％ 10 30.487 Nerol 0.6％ 11 35.138 Octadiene 0.7％

[0050] II. Comparative Examples

[0051] Comparative Example 1

[0052] The preparation method of the small molecule terpene fragrance substance in this comparative example adopts the following steps:

[0053] Nitrogen protective gas was filled into the cracking kettle containing 300 g of squalene. Starting from an initial temperature of 200 °C, it was heated to 300 °C at a rate of 40 °C / min and maintained for 1 h, then heated to 400 °C at a rate of 30 °C / min and maintained for 1 h, and finally heated to 500 °C at a rate of 20 °C / min and maintained for 1 h. The products were squalene (200 °C), isoprene, squalene (300 °C), isoprene, limonene, benzene, toluene, styrene (400 °C), isoprene, benzene, toluene, styrene (500 °C). It can be seen that for macromolecular terpene alcohols such as squalene, using the high-temperature cracking method, the main products are volatile isoprene and harmful substances such as benzene and toluene. This process is not suitable for the synthesis of fragrance small molecule terpenes.

[0054] Comparative Example 2

[0055] The preparation method of the small molecule terpene fragrance substance in this comparative example is only different from that of Example 3 in that:

[0056] The preparation of titanium silicalite in step (2) is different: the material ratio of the reaction solution tetrapropylammonium hydroxide (TPAOH):NaOH:H 2 O:EtOH is 18:0.3:300:150. Among them, NaOH is dissolved in deionized water, and TPAOH and absolute ethanol are stirred and mixed. Then 0.6 mL of TEOS (tetraethyl orthosilicate) is added dropwise and stirred evenly. After stirring for 12 h, 1 / 100 molar ratio of tetrabutyl titanate (TBOT) is added, and it is put into the reaction kettle and heated to 130 °C. After 72 h, the reaction kettle is taken out and cooled to room temperature. The product is washed with deionized water and dried at 90 °C. This molecular sieve is a porous titanium silicalite, which is a non-three-dimensional ordered hierarchical pore titanium silicalite.

[0057] Adopting the squalene degradation step of Example 3, the main cracking product is squalene (mass ratio of 90%), and the rest are octylidiene (8%) and nerol (2%). It can be seen that the degradation effect of ordinary molecular sieve is significantly inferior to that of three-dimensional ordered hierarchical pore titanium silicalite.

Claims

1. A preparation method of a small molecule terpene flavor substance, characterized in that, it comprises the following steps: A macromolecular terpene compound, silver vanadate and a titanium silicalite molecular sieve catalyst carry out a photocatalytic reaction in an oxidation environment to generate a small molecule terpene flavor substance; The titanium silicalite molecular sieve catalyst is prepared by mixing a tetrapropylammonium hydroxide solution and a sodium hydroxide solution to form a reaction solution, adding three-dimensional ordered macroporous carbon to the reaction solution, drying, then adding tetraethyl orthosilicate and mixing evenly, adding tetrabutyl titanate after standing, putting it into a reaction kettle and heating to 130-220 °C, taking it out after 24-72 h and cooling to room temperature, washing and drying, and then calcining in an air atmosphere at 400-700 °C for 5-24 h; The macromolecular terpene compound is selected from solanesol, β-carotene, squalene; The molar ratio of the macromolecular terpene compound to silver vanadate is 30-80:1; The mass ratio of the macromolecular terpene compound to the titanium silicalite molecular sieve is 200-300:1; The photocatalytic reaction is carried out in an ionic liquid; the ionic liquid is a trihexyltetradecylphosphonium salt solution; The conditions of the photocatalytic reaction include light irradiation and heating; the heating temperature is 100-200 °C; The oxidation environment is achieved by adding hydrogen peroxide to the system.

2. The preparation method of the small molecule terpene flavor substance according to claim 1, characterized in that, the heating time of the photocatalytic reaction is 3-10 h.

3. The preparation method of the small molecule terpene flavor substance according to claim 1, characterized in that, the mass fraction of hydrogen peroxide in the system is 0.5-1%.

Images