Natural heliotropin synthesis and treatment process

Abstract

The present invention discloses a natural heliotropin synthesis and treatment process, and belongs to the technical field of compound synthesis, the natural heliotropin synthesis and treatment process comprises isomerization treatment, oxidation treatment, reduction treatment, alkali washing treatment, water washing treatment and rectification treatment, wherein the isomerization treatment comprises feeding and reaction, end point monitoring, distillation purification and segmented collection; the oxidation treatment comprises reaction configuration, temperature and time length control and end point judgment. According to the method, safrole is adopted as a raw material, synthesis is performed through isomerization treatment and oxidation treatment, then a special aftertreatment process is performed, the wastewater discharge amount in the heliotropin aftertreatment stage is greatly reduced, the heliotropin yield is remarkably increased, alkali washing wastewater is treated and effectively reused in the alkali washing process, and the environmental pollution is reduced. The alkali washing wastewater amount is effectively reduced, and the wastewater treatment cost is reduced. Meanwhile, the hydrolysis loss of the heliotropin in the alkali washing process is also reduced, and the yield of the heliotropin is increased.

Description

Technical Field

[0001] The invention belongs to the technical field of compound synthesis, and in particular relates to a synthesis and treatment process of natural heliotropin. Background Art

[0002] Natural jasminaldehyde, chemical name: 3,4-methylenedioxybenzaldehyde, also known as piperonal, is an organic compound with the chemical formula C8H6O3. White or light yellow crystals. Boiling point 261-263℃, freezing point>35℃, soluble in 4 volume 95% ethanol and oily spices. It has a sweet bean fragrance and anise fragrance, slightly spicy, some like perfume grass (commonly known as sunflower), and cherry fragrance, which is weak and long. The taste is a strong sweet floral fragrance, spicy and slightly bitter. It is suitable for high and low-end flavors, and can be used in sunflower, violet, carnation, sweet bean flower, acacia, shy flower, hawthorn flower, newly cut grass, osmanthus, lilac, lily of the valley, honeysuckle, vanilla, frangipani. It is also widely used in edible flavors, and can be used in flavors such as vanilla beans, cherries, peaches, plums, strawberries, cola, rum, maple, nuts, etc. It can also be used in tobacco flavors.

[0003] Currently, there are two main routes for synthesis using piperonyl cyclopentane and safrole as raw materials. However, in the current post-treatment process, the alkaline washing step has disadvantages such as large amount of wastewater, hydrolysis of jasminoids during treatment, and large losses. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the disadvantages of the prior art and provide a natural heliotropin synthesis and treatment process.

[0005] The technical solution adopted to solve the above technical problems is: a natural jasminoid synthesis and treatment process, comprising:

[0006] Step 1) Isomerization treatment:

[0007] Feeding and reaction: add safrole and potassium hydroxide in proportion to an alkali-resistant reaction kettle and heat and stir;

[0008] Monitoring endpoint: sampling every hour for gas chromatography analysis until the safrole residue is less than 1%;

[0009] Distillation purification: Raise the temperature to 150-160°C and distill isosafrole through a fractionating column;

[0010] Segment collection: separation of head and tail segments;

[0011] Step 2) Oxidation treatment:

[0012] Reaction configuration: add isosafrole and deionized water in a mass ratio of 1:3 into a glass washing bottle, introduce ozone, and control the ozone flow rate at 5-6L / min;

[0013] Temperature control and duration: maintain the reaction temperature at 10-15°C and react continuously for 10 hours;

[0014] End point judgment: the solution changes from colorless to light yellow turbid, and jasminoid crystals appear, which is the crude jasminoid;

[0015] Step 3) Reduction process:

[0016] Add 600 g of 10% sodium pyrosulfite aqueous solution to the reaction solution for reduction to remove the peroxide generated during the oxidation process, stand the solution for stratification, separate the aqueous phase, and discharge the lower aqueous phase;

[0017] Step 4) Alkaline washing treatment:

[0018] After the reduction is completed, the crude jasminaldehyde is separated from the aqueous phase and poured into a three-necked flask to enter the alkaline washing step;

[0019] Step 5) washing treatment: after the crude jasminaldehyde product is washed with alkali, the aqueous phase is separated, and then 200 g of clean water is added for washing, and the aqueous phase is separated after standing;

[0020] Step 6) distillation treatment: The treated crude jasminaldehyde is transferred into a three-necked flask and then distilled to obtain high-purity jasminaldehyde.

[0021] Preferably, in the feeding and reaction links of the isomerization treatment step, the weight ratio of safrole to potassium hydroxide is 20:1.

[0022] Preferably, in the feeding and reaction links of the isomerization treatment step, a 300 mm glass distillation tower and a Roots vacuum pump are used simultaneously for vacuum heating and reflux, the temperature control is set to 100-115° C., the vacuum degree is set to 90-150 Pa, and the stirring speed is set to 300 r / min.

[0023] Preferably, in the oxidation treatment step, ozone is generated by an ozone generator, and ozone is introduced into the glass washing bottle using an impact aeration head, with an ozone content of 40 mg / L.

[0024] Preferably, during the distillation treatment, the outlet of the three-necked flask is connected to a 300 mm distillation tower, and the parameters of the distillation tower are set as follows: the vacuum degree is set to 90-150 Pa, the temperature of the initial distillation stage is set to 130° C., and the temperature of the main distillation stage is set to 160° C.

[0025] Preferably, the alkali washing step includes three methods:

[0026] Alkali washing method 1: add 600g of 10% sodium carbonate aqueous solution for direct alkali washing, stir for 15 minutes, let stand and separate, and recover the alkali solution at the same time;

[0027] Alkaline washing method 2: Take 500g of the upper liquid, add 30g of sodium carbonate, stir, dissolve and reuse;

[0028] Alkali washing method three: distill the sodium carbonate aqueous solution after alkali washing under normal pressure to evaporate the water therein, then add 30g of sodium carbonate, stir and dissolve, and recycle.

[0029] Preferably, in the alkali washing method 1, recovering the alkali solution specifically includes the following steps:

[0030] Pretreatment: Filter the solution to remove solid impurities and suspended matter;

[0031] Concentration: The sodium carbonate solution is concentrated by passing it through an evaporator to remove water and increase the concentration of the solution.

[0032] Preferably, during the concentration process, the sodium carbonate solution is concentrated by multiple-effect evaporation.

[0033] Preferably, the fractionation column in the isomerization treatment step is a packed fractionation column, and an air bag is arranged between the top of the fractionation column and the packing layer, and the air bag is sealed and filled with heat transfer oil. When the heat transfer oil is heated, the volume of the air bag expands and squeezes the filler in the packing layer downward to reduce the gap between the fillers.

[0034] Preferably, a U-shaped shape memory alloy sheet is provided between the top of the distillation column and the airbag, and the shape memory alloy consists of two long sections and a connecting section fixed between the two long sections. One long section of the shape memory alloy abuts against the top of the distillation column, and the other long section contacts the surface of the airbag, so that under high-temperature heating, the shape extruded alloy bends and deforms, and the two long sections of the shape extruded alloy are in a state of being unfolded with each other, and the long section located at the bottom squeezes the airbag in the direction of the packing layer.

[0035] The beneficial effects of the present invention are as follows:

[0036] (1) In the present invention, safrole is used as a raw material, and is synthesized by isomerization treatment and oxidation treatment, and then a special post-treatment process is used, so that the wastewater discharge in the post-treatment stage of jasminoids is greatly reduced, and the yield of jasminoids is significantly increased;

[0037] (2) In the present invention, the alkali washing wastewater is treated and effectively reused in the alkali washing process, which effectively reduces the amount of alkali washing wastewater and reduces the cost of wastewater treatment. At the same time, the hydrolysis loss of jasminoids in the alkali washing process is also reduced, and the yield of jasminoids is increased;

[0038] (3) In the present invention, the volume of the heat transfer oil expands after being heated, thereby expanding the volume of the air bag and squeezing the fillers in the fractionation column, so that the gaps between the fillers are reduced. This can avoid the phenomenon of "foam entrainment" caused by the entrainment of the isosafrole vapor with the solution during the distillation purification process, thereby causing a decrease in the concentration of isosafrole. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a schematic flow chart of a method for synthesizing and treating a natural hediocarbaldehyde in the present invention;

[0040] Figure 2 It is a schematic flow diagram of the isomerization treatment method of the present invention;

[0041] Figure 3 It is a schematic flow diagram of the oxidation treatment method in the present invention;

[0042] Figure 4 It is a schematic diagram of the method flow of the alkali washing step in the present invention. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0044] Some of the equipment used in the present invention comes from the following sources:

[0045] The ozone generator was purchased from Jinan Hailin Ozone Technology Co., Ltd., model HLS-20PY, ozone output: 20g / h; the heat-collecting constant temperature heating magnetic stirrer was purchased from Shanghai Yushen Instrument Co., Ltd., model DF101S; the Roots vacuum pump was purchased from Zhengzhou Great Wall Science and Technology Industry and Trade Co., Ltd., model SHB-111; the gas chromatograph was purchased from Hewlett-Packard of the United States, model hp Hewlett 890.

[0046] Example 1

[0047] like Figure 1-Figure 4 As shown, this embodiment provides a natural jasminoid synthesis and treatment process, comprising:

[0048] Step 1) Isomerization treatment:

[0049] Feeding and reaction: safrole and potassium hydroxide are added to an alkali-resistant reactor in a ratio of 20:1. Specifically, the weight of safrole is 1000 g and the weight of potassium hydroxide is 50 g. A heat-collecting constant temperature heating magnetic stirrer is used for heating and stirring. A 300 mm glass distillation tower and a Roots vacuum pump are used for vacuum heating and reflux. The temperature control is set to 100 ° C., the vacuum degree is set to 150 Pa, and the stirring speed is set to 300 r / min.

[0050] Monitoring endpoint: Using a gas chromatograph, take samples every hour for gas chromatography analysis until the safrole residue is less than 1%;

[0051] Distillation purification: The temperature is raised to 152°C, and isosafrole is distilled out through a fractionation column. The fractionation column is a packed fractionation column, and an air bag is placed between the top of the fractionation column and the packing layer. The air bag is sealed and filled with heat transfer oil. After the heat transfer oil is heated, the volume of the air bag expands and squeezes the packing in the packing layer downward to reduce the gap between the packings. In this way, when the temperature rises and the amount of steam is large, by reducing the gap between the packings, when the steam entrains the solution, the droplets of the solution contact the packing more quickly and timely, thereby avoiding the solution being entrained by the steam, that is, "foam entrainment", resulting in a decrease in the concentration of isosafrole and purity. In addition, a U-shaped shape memory alloy sheet is provided between the top of the fractionating column and the airbag, and the shape memory alloy is composed of two long sections and a connecting section fixed between the two long sections. One long section of the shape memory alloy abuts against the top of the fractionating column, and the other long section contacts the surface of the airbag, so that under high temperature heating, the shape extruded alloy is bent and deformed, and the two long sections of the shape extruded alloy are in a state of being unfolded with each other, and the long section located at the bottom squeezes the airbag toward the direction of the packing layer, so that the squeezing force of the airbag on the packing is increased, so that the gap between the packing can be further reduced;

[0052] Segmented collection: Separate the head and tail segments to obtain isosafrole with a content of 97.8% (cis-isosafrole 15.6% / trans-isosafrole 82.2%), and the yield can reach 86%;

[0053] Step 2) Oxidation treatment:

[0054] Reaction configuration: add isosafrole and deionized water in a mass ratio of 1:3 into a glass washing bottle, start the ozone generator at the same time, and introduce ozone into the glass washing bottle through an aeration impact head. The ozone content is 40 mg / L, and the ozone flow rate is controlled at 5 L / min;

[0055] Temperature control and duration: maintain the reaction temperature at 15°C and react continuously for 10 hours;

[0056] End point judgment: the solution changes from colorless to light yellow turbid, and jasminoid crystals appear, which is the crude jasminoid;

[0057] Step 3) Reduction process:

[0058] Add 600 g of 10% sodium pyrosulfite aqueous solution to the reaction solution for reduction to remove the peroxide generated during the oxidation process, stand the solution for stratification, separate the aqueous phase, and discharge the lower aqueous phase;

[0059] Step 4) Alkaline washing treatment:

[0060] After the reduction is completed, the crude jasminaldehyde is separated from the aqueous phase and poured into a three-necked flask to enter the alkali washing step. The alkali washing step is as follows: 600g of 10% sodium carbonate aqueous solution is added to directly perform alkali washing, and then the mixture is stirred for 15 minutes and allowed to stand for stratification, and the alkali solution is recovered at the same time;

[0061] Step 5) washing treatment: after the crude jasminaldehyde product is washed with alkali, the aqueous phase is separated, and then 200 g of clean water is added for washing, and the aqueous phase is separated after standing;

[0062] Step 6) distillation treatment: the treated crude jasminaldehyde is transferred to a three-necked flask, the outlet of the three-necked flask is connected to a 300 mm distillation tower, the parameters of the distillation tower are set as follows: the vacuum degree is set to 98 Pa, the initial distillation stage temperature is set to 130 ° C, the main distillation stage temperature is set to 160 ° C, and then distillation is carried out to obtain high-purity jasminaldehyde.

[0063] The specific recovery of alkali solution includes the following:

[0064] Pretreatment: Filter the solution to remove solid impurities and suspended matter;

[0065] Concentration: The sodium carbonate solution is concentrated by passing it through an evaporator to remove water and increase the concentration of the solution.

[0066] Example 2

[0067] like Figure 1-Figure 4 As shown, this embodiment provides a natural jasminoid synthesis and treatment process, comprising:

[0068] Step 1) Isomerization treatment:

[0069] Feeding and reaction: safrole and potassium hydroxide are added to an alkali-resistant reactor in a ratio of 20:1. Specifically, the weight of safrole is 1000 g and the weight of potassium hydroxide is 50 g. A heat-collecting constant temperature heating magnetic stirrer is used for heating and stirring. A 300 mm glass distillation tower and a Roots vacuum pump are used for vacuum heating and reflux. The temperature control is set to 115° C., the vacuum degree is set to 950 Pa, and the stirring speed is set to 300 r / min.

[0070] Monitoring endpoint: Using a gas chromatograph, take samples every hour for gas chromatography analysis until the safrole residue is less than 1%;

[0071] Distillation purification: The temperature is raised to 150°C, and isosafrole is distilled out through a fractionation column. The fractionation column is a packed fractionation column, and an air bag is placed between the top of the fractionation column and the packing layer. The air bag is sealed and filled with heat transfer oil. After the heat transfer oil is heated, the volume of the air bag expands and squeezes the packing in the packing layer downward to reduce the gap between the packings. In this way, when the temperature rises and the amount of steam is large, by reducing the gap between the packings, when the steam entrains the solution, the droplets of the solution contact the packing more quickly and timely, thereby avoiding the solution being entrained by the steam, that is, "foam entrainment", resulting in a decrease in the concentration of isosafrole and purity. In addition, a U-shaped shape memory alloy sheet is provided between the top of the fractionating column and the airbag, and the shape memory alloy is composed of two long sections and a connecting section fixed between the two long sections. One long section of the shape memory alloy abuts against the top of the fractionating column, and the other long section contacts the surface of the airbag, so that under high temperature heating, the shape extruded alloy is bent and deformed, and the two long sections of the shape extruded alloy are in a state of being unfolded with each other, and the long section located at the bottom squeezes the airbag toward the direction of the packing layer, so that the squeezing force of the airbag on the packing is increased, so that the gap between the packing can be further reduced;

[0072] Segmented collection: Separate the head and tail segments to obtain isosafrole with a content of 97.8% (cis-isosafrole 15.6% / trans-isosafrole 82.2%), and the yield can reach 86%;

[0073] Step 2) Oxidation treatment:

[0074] Reaction configuration: add isosafrole and deionized water in a mass ratio of 1:3 into a glass washing bottle, start the ozone generator at the same time, and introduce ozone into the glass washing bottle through an aeration impact head. The ozone content is 40 mg / L, and the ozone flow rate is controlled at 6 L / min;

[0075] Temperature control and duration: maintain the reaction temperature at 12°C and react continuously for 10 hours;

[0076] End point judgment: the solution changes from colorless to light yellow turbid, and jasminoid crystals appear, which is the crude jasminoid;

[0077] Step 3) Reduction process:

[0078] Add 600 g of 10% sodium pyrosulfite aqueous solution to the reaction solution for reduction to remove the peroxide generated during the oxidation process, stand the solution for stratification, separate the aqueous phase, and discharge the lower aqueous phase;

[0079] Step 4) Alkaline washing treatment:

[0080] After the reduction is completed, the crude jasminaldehyde is separated from the aqueous phase and poured into a three-necked flask to enter the alkali washing step. The alkali washing step is as follows: 500g of the upper liquid is taken, and 30g of sodium carbonate is added and stirred, and then dissolved and reused;

[0081] Treatment of residual liquid: distill the sodium carbonate aqueous solution after alkali washing under normal pressure to evaporate the water, then add 30g of sodium carbonate, stir and dissolve, and recycle;

[0082] Step 5) washing treatment: after the crude jasminaldehyde product is washed with alkali, the aqueous phase is separated, and then 200 g of clean water is added for washing, and the aqueous phase is separated after standing;

[0083] Step 6) distillation treatment: the treated crude jasminaldehyde is transferred to a three-necked flask, the outlet of the three-necked flask is connected to a 300 mm distillation tower, the parameters of the distillation tower are set as follows: the vacuum degree is set to 90 Pa, the initial distillation stage temperature is set to 130 ° C, the main distillation stage temperature is set to 160 ° C, and then distillation is carried out to obtain high-purity jasminaldehyde.

[0084] Example 3

[0085] like Figure 1-Figure 4 As shown, this embodiment provides a natural jasminoid synthesis and treatment process, comprising:

[0086] Step 1) Isomerization treatment:

[0087] Feeding and reaction: safrole and potassium hydroxide are added to an alkali-resistant reactor in a ratio of 20:1. Specifically, the weight of safrole is 1000 g and the weight of potassium hydroxide is 50 g. A heat-collecting constant temperature heating magnetic stirrer is used for heating and stirring. A 300 mm glass distillation tower and a Roots vacuum pump are used for vacuum heating and reflux. The temperature control is set to 108° C., the vacuum degree is set to 90 Pa, and the stirring speed is set to 300 r / min.

[0088] Monitoring endpoint: Using a gas chromatograph, take samples every hour for gas chromatography analysis until the safrole residue is less than 1%;

[0089] Distillation purification: The temperature is raised to 160°C, and isosafrole is distilled out through a fractionation column. The fractionation column is a packed fractionation column, and an air bag is placed between the top of the fractionation column and the packing layer. The air bag is sealed and filled with heat transfer oil. After the heat transfer oil is heated, the volume of the air bag expands and squeezes the packing in the packing layer downward to reduce the gap between the packings. In this way, when the temperature rises and the amount of steam is large, by reducing the gap between the packings, when the steam entrains the solution, the droplets of the solution contact the packing more quickly and timely, thereby avoiding the solution being entrained by the steam, that is, "foam entrainment", resulting in a decrease in the concentration of isosafrole and purity. In addition, a U-shaped shape memory alloy sheet is provided between the top of the fractionating column and the airbag, and the shape memory alloy is composed of two long sections and a connecting section fixed between the two long sections. One long section of the shape memory alloy abuts against the top of the fractionating column, and the other long section contacts the surface of the airbag, so that under high temperature heating, the shape extruded alloy is bent and deformed, and the two long sections of the shape extruded alloy are in a state of being unfolded with each other, and the long section located at the bottom squeezes the airbag toward the direction of the packing layer, so that the squeezing force of the airbag on the packing is increased, so that the gap between the packing can be further reduced;

[0090] Segmented collection: Separate the head and tail segments to obtain isosafrole with a content of 97.8% (cis-isosafrole 15.6% / trans-isosafrole 82.2%), and the yield can reach 86%;

[0091] Step 2) Oxidation treatment:

[0092] Reaction configuration: add isosafrole and deionized water in a mass ratio of 1:3 into a glass washing bottle, start the ozone generator at the same time, and introduce ozone into the glass washing bottle through an aeration impact head. The ozone content is 40 mg / L, and the ozone flow rate is controlled at 5.5 L / min;

[0093] Temperature control and duration: maintain the reaction temperature at 10°C and react continuously for 10 hours;

[0094] End point judgment: the solution changes from colorless to light yellow turbid, and jasminoid crystals appear, which is the crude jasminoid;

[0095] Step 3) Reduction process:

[0096] Add 600 g of 10% sodium pyrosulfite aqueous solution to the reaction solution for reduction to remove the peroxide generated during the oxidation process, stand the solution for stratification, separate the aqueous phase, and discharge the lower aqueous phase;

[0097] Step 4) Alkaline washing treatment:

[0098] After the reduction is completed, the crude product of jasminaldehyde is separated from the aqueous phase and poured into a three-necked flask to enter the alkali washing step. The alkali washing step is as follows: the sodium carbonate aqueous solution after the alkali washing is subjected to atmospheric distillation to evaporate the water therein, and then 30g of sodium carbonate is added to stir and dissolve, and then recycled;

[0099] Step 5) washing treatment: after the crude jasminaldehyde product is washed with alkali, the aqueous phase is separated, and then 200 g of clean water is added for washing, and the aqueous phase is separated after standing;

[0100] Step 6) distillation treatment: the treated crude jasminaldehyde is transferred to a three-necked flask, the outlet of the three-necked flask is connected to a 300 mm distillation tower, the parameters of the distillation tower are set as follows: the vacuum degree is set to 150 Pa, the initial distillation stage temperature is set to 130 ° C, the main distillation stage temperature is set to 160 ° C, and then distillation is carried out to obtain high-purity jasminaldehyde.

[0101] Tables 1 to 5 are the experimental records of each step in Example 1 to Example 3. The experimental results of the oxidation treatment step are shown in Table 1:

[0102]

[0103] Table 1

[0104] The experimental results of the reduction treatment step are shown in Table 2:

[0105]

[0106]

[0107] Table 2 Alkaline washing treatment step experimental results are shown in Table 3:

[0108]

[0109] Table 3 Water washing treatment step experimental results are shown in Table 4:

[0110]

[0111] Table 4 Distillation treatment step experimental results are shown in Table 5:

[0112]

[0113] Table 5

[0114] It can be seen from Tables 1 to 5 that: Example 1 directly uses sodium carbonate aqueous solution to alkali wash the crude natural jasminaldehyde, and the loss is large, reaching 22.7%, and the yield of natural jasminaldehyde after distillation is 61.09%; Example 2 uses the upper layer recycled alkali washing water after standing and adds 30g sodium carbonate to alkali wash the crude natural jasminaldehyde, and the loss rate is significantly reduced to only 9.09%, and the yield of natural jasminaldehyde after distillation is 71.28%. Example 3 uses the recycled alkali water after distillation and adds 30g sodium carbonate to alkali wash the crude natural jasminaldehyde, and the loss rate is 9.93%, and the yield of natural jasminaldehyde after distillation is 71.96%.

[0115] From the experimental data, the loss rate of Example 2 is the lowest, and the yield of natural jasminaldehyde in Example 3 is the highest. The loss rate of Experiment 1 is the highest, and the yield of natural jasminaldehyde is the lowest. Compared with Example 1, the loss rate of Example 2 and Example 3 decreased by about 12%, the yield of natural jasminaldehyde increased by about 10%, and the amount of alkali washing wastewater each time was reduced by 70-80%, greatly reducing the cost of wastewater treatment. Compared with Example 3, the yield of natural jasminaldehyde in Example 2 was 0.66% lower, and the loss rate was also 0.84% ​​lower. Considering that Example 2 directly reuses alkaline water and omits the wastewater distillation link, the method of Example 2 is the best method.

[0116] Comparative Example 1

[0117] The traditional method for preparing jasminaldehyde includes:

[0118] Raw materials: vanillin, acetone, sodium hydroxide (NaOH) or potassium hydroxide (KOH), acid (such as hydrochloric acid HCl or sulfuric acid H2SO4);

[0119] Experimental steps:

[0120] Prepare the reaction mixture: Add appropriate amounts of vanillin and acetone to a reaction vessel. Typically, the molar ratio of vanillin to acetone is 1:1 to 1:2.

[0121] Adding alkaline catalyst: Slowly add an aqueous solution of sodium hydroxide or potassium hydroxide under stirring. The amount of base is usually 1-2 times the molar number of vanillin.

[0122] Heating to reflux: The reaction mixture is heated to reflux, usually at 60-80°C for several hours. During the reflux process, vanillin and acetone undergo a condensation reaction under alkaline conditions to form heliotropin.

[0123] Acidification: After reflux is complete, cool the mixture and then acidify by slowly adding an acid (such as hydrochloric acid or sulfuric acid) until the pH reaches neutral or slightly acidic (pH 5-6).

[0124] Extraction: After acidification, the mixture will separate into two layers. Use a separatory funnel to separate the aqueous layer and the organic layer. The organic layer contains heliotropin.

[0125] Purification: Wash the organic layer with saturated brine to remove residual alkali and acidic substances. Dry the organic layer by adding anhydrous sodium sulfate or other desiccant. Remove the desiccant by filtration, and then further purify the jasminaldehyde by vacuum distillation or column chromatography.

[0126] Crystallization: Cool the purified heliotropin solution to allow it to crystallize. Collect the crystals by filtration.

[0127] Drying: The collected jasminoid crystals are dried in a vacuum dryer to obtain pure jasminoid. The yield of jasminoid prepared by the traditional preparation method is between 48-55%, which is much lower than the yield of jasminoid in Examples 1-3.

[0128] Note: Wear appropriate personal protective equipment during the reaction, such as lab coat, gloves and goggles. Make sure to operate in a well-ventilated environment, as acetone and vanillin are volatile. Control the reaction temperature and time to avoid side reactions. Wastewater should be properly disposed of to avoid environmental pollution.

[0129] Gas chromatography analysis execution standard:

[0130] The standard for analyzing spices and flavors by gas chromatography is ASTM D3612; the standard for determining spices and flavors by gas chromatography is ISO 12228; and the official analytical method standard in the food and agriculture field is AOACI International.

[0131] Equipment needed:

[0132] Gas chromatograph: equipped with an inlet, chromatographic column, detector (such as F ID, TCD or MSD) and a data recording system; Chromatographic column: a capillary column suitable for analyzing safrole; Detector: the most commonly used is a flame ionization detector (F ID), but other types such as a mass spectrometer detector (MSD) can also be used; Carrier gas supply system: provides carrier gas such as helium or nitrogen; Microinjector: used for accurate injection; Sample preparation tools: such as vortex mixers, centrifuges, balances, etc.; Standard: safrole of known purity.

[0133] When performing gas chromatography analysis, you should ensure that the following best practices are followed: use appropriate standards for calibration to establish a calibration curve; ensure that the chromatograph is operating in optimal working condition and perform maintenance and calibration when necessary; keep the laboratory environment stable, especially temperature and humidity, as they will affect the chromatographic results; take appropriate safety measures as hazardous chemicals may be involved in the operation; with the above steps and equipment, the content of safrole can be effectively confirmed by gas chromatography analysis.

[0134] Specifically, the following methods are included: 1. Sample pretreatment

[0135] Before gas chromatography analysis, samples usually need to be pretreated:

[0136] Extraction: The reaction mixture is extracted with an appropriate organic solvent (such as n-hexane, dichloromethane, etc.) to separate safrole.

[0137] Cleanup: If the extract contains interfering substances, it may be necessary to further purify the sample by solid phase extraction (SPE) or other cleanup techniques.

[0138] Derivatization: If safrole is not volatile, derivatization may be necessary to convert it into a volatile derivative.

[0139] 2. Selection of chromatographic conditions

[0140] Chromatographic column: Choose a chromatographic column suitable for separating safrole and its reaction products, usually a capillary column, and the stationary phase may be non-polar such as DB-5, or a polar stationary phase such as DB-WAX.

[0141] Detector: A flame ionization detector (FID) or a mass spectrometer (MS) is usually used.

[0142] Carrier gas: Helium or hydrogen is commonly used as carrier gas.

[0143] Inlet temperature: set according to the boiling point of safrole, usually between 200-300℃.

[0144] Column temperature: adopt programmed temperature rising method, starting from a low temperature and gradually rising to the final temperature, usually between 50-300℃.

[0145] Detector temperature: usually set between 250-350℃.

[0146] 3. Preparation of Standard Curve

[0147] Prepare a series of safrole standard solutions with different concentrations.

[0148] The standard solutions of each concentration were analyzed by gas chromatography.

[0149] Draw a standard curve of peak area (or peak height) and concentration.

[0150] 4. Sampling and analysis

[0151] Inject the processed sample into the gas chromatograph.

[0152] The safrole peak was identified based on the retention time.

[0153] The content of safrole in the sample was calculated based on the peak area (or peak height) and the standard curve.

[0154] 5. Data Processing

[0155] The chromatography workstation software was used for data acquisition and processing.

[0156] Confirm whether the shape and separation of the chromatographic peak meet the requirements.

[0157] The retention time and peak area of ​​safrole were recorded for quantitative analysis.

[0158] Note:

[0159] Ensure that contamination is avoided during sample handling and analysis.

[0160] Instruments should be calibrated regularly using standard substances to ensure the accuracy of analysis results.

[0161] Consider the effects that reaction conditions and sample characteristics may have on the chromatography.

[0162] Through the above steps, the gas chromatograph can be effectively used to analyze the content of safrole in the reaction process of isosafrole and potassium hydroxide.

[0163] The above are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention.

Claims

1. A natural jasminoid synthesis and treatment process, characterized in that: include: Step 1) Isomerization treatment: Feeding and reaction: add safrole and potassium hydroxide in proportion to an alkali-resistant reaction kettle and heat and stir; Monitoring endpoint: sampling every hour for gas chromatography analysis until the safrole residue is less than 1%; Distillation purification: Raise the temperature to 150-160°C and distill isosafrole through a fractionating column; Segment collection: separation of head and tail segments; Step 2) Oxidation treatment: Reaction configuration: add isosafrole and deionized water in a mass ratio of 1:3 into a glass washing bottle, introduce ozone, and control the ozone flow rate at 5-6L / min; Temperature control and duration: maintain the reaction temperature at 10-15°C and react continuously for 10 hours; End point judgment: the solution changes from colorless to light yellow turbid, and jasminoid crystals appear, which is the crude jasminoid; Step 3) Reduction process: Add 600 g of 10% sodium pyrosulfite aqueous solution to the reaction solution for reduction to remove the peroxide generated during the oxidation process, stand the solution for stratification, separate the aqueous phase, and discharge the lower aqueous phase; Step 4) Alkaline washing treatment: After the reduction is completed, the crude jasminaldehyde is separated from the aqueous phase and poured into a three-necked flask to enter the alkaline washing step; Step 5) washing treatment: after the crude jasminaldehyde product is washed with alkali, the aqueous phase is separated, and then 200 g of clean water is added for washing, and the aqueous phase is separated after standing; Step 6) distillation treatment: The treated crude jasminaldehyde is transferred into a three-necked flask and then distilled to obtain high-purity jasminaldehyde.

2. The synthesis and treatment process of natural jasminaldehyde according to claim 1, characterized in that: In the feeding and reaction link of the isomerization treatment step, the weight ratio of safrole to potassium hydroxide is 20:

1.

3. The synthesis and treatment process of natural jasminaldehyde according to claim 1, characterized in that: In the feeding and reaction links of the isomerization treatment step, a 300 mm glass distillation tower and a Roots vacuum pump are used simultaneously for vacuum heating and reflux, the temperature control is set to 100-115° C., the vacuum degree is set to 90-150 Pa, and the stirring speed is set to 300 r / min.

4. The synthesis and treatment process of natural jasminaldehyde according to claim 1, characterized in that: In the oxidation treatment step, ozone is generated by an ozone generator, and ozone is introduced into the glass washing bottle using an impact aeration head, with an ozone content of 40 mg / L.

5. The synthesis and treatment process of natural jasminaldehyde according to claim 1, characterized in that: During the distillation treatment, the outlet of the three-necked flask was connected to a 300 mm distillation tower, and the parameters of the distillation tower were set as follows: the vacuum degree was set to 90-150 Pa, the temperature of the initial distillation stage was set to 130° C., and the temperature of the main distillation stage was set to 160° C.

6. The synthesis and treatment process of natural jasminaldehyde according to claim 1, characterized in that: The alkali washing process includes three methods: Alkali washing method 1: add 600g of 10% sodium carbonate aqueous solution for direct alkali washing, stir for 15 minutes, let stand and separate, and recover the alkali solution at the same time; Alkaline washing method 2: Take 500g of the upper liquid, add 30g of sodium carbonate, stir, dissolve and reuse; Alkali washing method three: distill the sodium carbonate aqueous solution after alkali washing under normal pressure to evaporate the water therein, then add 30g of sodium carbonate, stir and dissolve, and recycle.

7. The synthesis and treatment process of natural jasminaldehyde according to claim 6, characterized in that: In the alkali washing method 1, the recovery of the alkali solution specifically includes the following: Pretreatment: Filter the solution to remove solid impurities and suspended matter; Concentration: The sodium carbonate solution is concentrated by passing it through an evaporator to remove water and increase the concentration of the solution.

8. The synthesis and treatment process of natural heliotropin according to claim 7, characterized in that: In the concentration process, the sodium carbonate solution is concentrated by means of multiple-effect evaporation.

9. The synthesis and treatment process of natural hediocarbaldehyde according to claim 1, characterized in that: The fractionation column in the isomerization treatment step is a packed fractionation column, and an air bag is arranged between the top of the fractionation column and the packing layer. The air bag is sealed and filled with heat transfer oil. When the heat transfer oil is heated, the volume of the air bag expands and squeezes the packing in the packing layer downward to reduce the gap between the packings.

10. The synthesis and treatment process of natural hediocarbaldehyde according to claim 9, characterized in that: A U-shaped shape memory alloy sheet is provided between the top of the fractionating column and the airbag. The shape memory alloy consists of two long sections and a connecting section fixed between the two long sections. One long section of the shape memory alloy abuts against the top of the fractionating column, and the other long section contacts the surface of the airbag, so that under high-temperature heating, the shape extruded alloy generates bending deformation, and the two long sections of the shape extruded alloy are in a state of being unfolded with each other, and the long section located at the bottom squeezes the airbag toward the packing layer.

Images