Green production process for synthesizing 1, 8-terpineol and preparing perfume-grade terpilenol by dehydrating 1, 8-terpineol

Abstract

The invention discloses a green production process for synthesizing 1, 8-terpineol and preparing perfume-grade terpilenol by dehydrating the 1, 8-terpineol, which comprises the steps of hydration reaction, centrifugal separation, acid water recovery, by-product recovery, dehydration reaction and secondary distillation. Wherein the turpentine hydration reaction conditions are as follows: a catalyst is composed of alpha-hydroxy acid and phosphoric acid or boric acid, intermittent stirring is performed at room temperature, the reaction is performed for 2-15 days, an IBC ton barrel can be adopted as a reaction tank, and the mass yield of terpin hydrate is greater than 100%. Citric acid or tartaric acid is adopted to catalyze the dehydration reaction of terpineol hydrate, and the selectivity of terpineol can reach 91% or above. Compared with a traditional process, the method has the advantages that the catalyst is low in corrosivity and does not need an enamel reaction kettle; the reaction is carried out at room temperature, and no cooling equipment is needed; centrifuging to obtain terpin hydrate crystals without alkali neutralization; acid water is easy to recycle, and almost no wastewater is discharged; an IBC barrel is used as a reactor, so that the equipment investment is low.

Description

Technical Field

[0001] The present invention relates to the technical field of deep processing of forest chemical products, and particularly relates to a green production process for synthesizing 1,8-terpene diol and dehydrating it to prepare perfume-grade terpineol. Background Art

[0002] 1,8-Terpene diol (hydrated terpene diol) is an intermediate for synthesizing terpineol and is also an expectorant, usually used for patients with acute or chronic bronchitis to dilute (relax) thick phlegm. The synthesis of 1,8-terpene diol by the reaction of pinene with water is separated from the reaction system in the form of hydrated terpene diol crystals. On the one hand, this is conducive to its separation and purification, and ultimately obtaining high-quality terpineol for perfume; on the other hand, this also makes it difficult to use heterogeneous catalysts such as cation resins and solid acids to replace the 30-38% sulfuric acid used in production, so as to solve the technical problems of reducing pollution, equipment corrosion and high energy consumption. Chinese Patent Application CN201710258186.4 discloses a green production method of hydrated terpene diol and terpineol. Specifically, after the hydration reaction in the two-step production of terpineol, the by-product red oil from the previous batch is added to wash the hydrated terpene diol crystals, and this method reduces the discharge of wastewater compared with the traditional water washing. Chinese Patent Application CN201110169483.4 discloses a process for preparing terpineol. Specifically, turpentine or industrial pinene is used to carry out a hydration reaction under acid catalysis and ultrasonic assistance, then left to stand for layering, neutralized and washed to obtain hydrated terpene diol crystal products and red oil, and then the hydrated terpene diol crystal products are dehydrated with dilute acid catalysis to generate butter mainly containing terpineol, and finally the terpineol product is obtained through rectification and purification.

[0003] Since the hydration reaction of pinene to form terpin diol is an exothermic reaction, it is advisable to carry out the reaction at 30 °C. When the temperature is high, terpene by-products such as limonene and terpinene will increase. Using 30% sulfuric acid as the catalyst, the heat release is large in the early stage of the reaction. During production, the cooling water temperature is usually controlled at 5 °C or even below 0 °C, often requiring a high-power refrigerator for cooling, resulting in high energy consumption. Moreover, using brine as the cooling medium is likely to cause corrosion of the equipment. At the same time, due to the use of 30% sulfuric acid as the catalyst, which has strong corrosiveness, the reaction needs to be carried out in an enamel reaction kettle. However, it is not easy to install baffles in the enamel reaction kettle, and the heat and mass transfer efficiency is not high. To increase the contact between the oil and water phases and improve the mixing effect, a relatively high stirring speed is required, and the material circulation volume is large. Coupled with the formation of terpin diol crystals, it is easy to cause accidents such as bending of the stirring shaft. The dehydration of hydrate terpin diol to synthesize terpineol, the main components of which are α-terpineol, and the relative contents of β-terpineol and γ-terpineol are also relatively high. The classic process for the dehydration reaction is to use a sulfuric acid solution of less than 0.2%, and stir the reaction under boiling reflux conditions, requiring the acid content of the input terpin diol crystals to be lower than 0.12%. The terpin diol crystals formed by hydration need to be neutralized with sodium hydroxide solution, and the residual sulfates will affect the catalytic performance of sulfuric acid. Multiple washings will produce a large amount of dilute acid water that is difficult to recover (Mou Daqing. Process Technology Improvement and Effect Analysis of Two-step Production of Medicinal Terpineol [J]. Biomass Chemical Engineering, 2010, 44(01): 27-30.).

[0004] The academic community believes that when phosphoric acid is used as the catalyst for the hydration reaction of pinene, no hydrate terpin diol (1,8-terpin diol) is produced in the crude product, but terpineol is directly obtained. On the other hand, phosphoric acid has a good effect on catalyzing the dehydration of hydrate terpin diol, and the alcohol content in the butter is more than 85% (Jiang Jianchun, Chu Fuxiang, Wang Yongqiang, et al. Modern Forest Products Chemical Engineering (Volume II) [M]. Beijing: Chemical Industry Press, 2024: 244-247.). This means that if the synthesis of hydrate terpin diol from pinene can be catalyzed by phosphoric acid, the hydrate terpin diol separated by centrifugation does not need to be neutralized with alkali (when catalyzed by sulfuric acid, neutralization is necessary), which will greatly reduce the generation of wastewater. Experiments show that when using phosphoric acid with a mass concentration <50% and following the sulfuric acid method for the pinene hydration reaction conditions at 20-30 °C for 24 h, no hydrate terpin diol can be obtained. If hydrate terpin diol is to be obtained, the reaction time needs to be extended to more than 240 h, or the phosphoric acid concentration needs to be increased to more than 50%, but the yield is relatively low (50-60%). Chinese Patent Application CN201810689839.9 discloses a method for synthesizing terpin diol from turpentine and preparing terpineol and terpinyl acetate. Using a phosphoric acid composite catalyst, the highest yield of hydrate terpin diol is 95.2%. However, there are still problems such as low yield of hydrate terpin diol and the need for fractional distillation to purify terpineol. Summary of the Invention

[0005] The present invention aims to overcome the problems of high energy consumption, low yield and the need to treat a large amount of wastewater existing in the traditional "two-step" process for synthesizing terpineol, and improve the atom economy of synthesizing hydrate terpene diol from turpentine and its dehydration to prepare terpineol through technological innovation, so as to develop a green synthesis process.

[0006] To achieve the above objectives, the present invention is realized through the following technical solutions:

[0007] A green production process for synthesizing 1,8-terpene diol and its dehydration to prepare perfume-grade terpineol, including a hydration reaction, centrifugal separation, acid water recovery, dehydration reaction and by-product recovery, characterized in that: the hydration reaction includes the following steps, adding turpentine (pinene content ≥ 85%), water, α-hydroxy acid composite catalyst and emulsifier into the reaction tank according to a mass ratio of 100:50-150:20-150:0.01-0.08, starting stirring, with the reaction temperature being 5-40°C and the reaction time being 2-10 days; the α-hydroxy acid composite catalyst is composed of α-hydroxy acid and phosphoric acid or boric acid; the α-hydroxy acid is composed of one or several of glycolic acid, lactic acid, mandelic acid, tartaric acid, malic acid, citric acid, gluconic acid, lactobionic acid; the order of adding the raw materials into the hydration reaction tank is water, catalyst, turpentine.

[0008] Further, the hydration reaction adopts intermittent stirring, 2-6 times per day, 1-5 minutes each time, with an interval of 6-12 hours each time.

[0009] Further, the catalyst for the hydration reaction is composed of α-hydroxy acid and phosphoric acid, and their mass ratio is 1-50:100.

[0010] Further, the catalyst for the hydration reaction is composed of α-hydroxy acid and boric acid, and their mass ratio is 100:1-60.

[0011] Further, the emulsifier is made from the following raw materials: sophorolipid, N-methyl-N,N-dialkyl chitosan quaternary ammonium salt, polyglycerol fatty acid ester, sodium citrate, sodium gluconate, nano-silica and water.

[0012] Further, the hydration reaction tank is an IBC ton barrel, with the inner liner made of high-density polyethylene, the outer frame welded and formed by hot-dip galvanized steel pipes, the bottom tray cast from steel plates, and plastic corner guards installed at the four bottom corners, and the diameter of the loading port is larger than the diameter of the stirring paddle.

[0013] Further, after the hydration reaction is completed, the crude hydrated terpineol in the reaction tank is taken out and separated by a centrifuge at a rotation speed of 800 - 1000 r / min and a filter screen aperture of 800 - 1000 meshes, and the centrifugate is collected; then, water accounting for 10% of the mass of the hydrated terpineol is added, the hydrated terpineol is washed and separated by a centrifuge, and this is repeated 3 times, and the centrifugates are combined; the collected centrifugate is allowed to stand and layer, the upper layer is a by-product containing isomers such as limonene, terpinene, and terpinolene, and the lower layer is acid water; the obtained acid water is returned to the reaction tank; after the obtained by-product is metered, it is added to the reaction tank together with turpentine as a raw material for the next hydration reaction.

[0014] Further, 1 - 10% of a catalyst needs to be added to the hydration reaction; the catalyst is phosphoric acid or α - hydroxycarboxylic acid.

[0015] Further, the dehydration reaction is to add the dehydrated hydrated terpineol to a dehydration reaction kettle equipped with an oil - water separator, and add water 2 - 3 times its mass and citric acid or tartaric acid 0 - 0.5‰ of its mass, and the temperature is controlled at 100°C - 105°C, and the reaction is carried out until no terpineol is distilled out.

[0016] Further, the dehydrated product of the hydrated terpineol is put into a distillation kettle equipped with an oil - water separator, water 2 - 3 times its mass is added, and β - molecular sieve 2 - 3% of its mass is added, heated to boiling, the crude terpineol distilled out in the first 10 min is collected and purified by vacuum fractional distillation; continue distilling until no terpineol is distilled out, and the collected product is used as perfume - grade terpineol; the hydrogen - type β - molecular sieve has a silica - alumina ratio of 25 - 30 and a particle size of ≤5 μm.

[0017] Compared with the prior art, the advantages and beneficial effects of the present invention are as follows:

[0018] 1. The hydration reaction of turpentine in the present invention can adopt intermittent stirring, and the total stirring time per day is about 6 min. Even if the reaction takes 15 days to complete (5 - 7 days in summer), the total stirring time required is only 90 min. While the traditional sulfuric acid method requires a high - speed stirring of a 11 - 15 kW motor for 24 h, consuming 264 - 360 degrees of electricity (Mou Daqing. Process Technology Improvement and Effect Analysis of Producing Medicinal Terpineol by Two - Step Method [J]. Biomass Chemical Engineering, 2010, 44(01): 27 - 30.). Assuming the use of the same motor, the new process only requires 5.5 - 16.5 degrees of electricity, and the electric energy can be saved by more than 93% only for the stirring motor of the reaction kettle. Moreover, the hydration reaction of the present invention has no intense heat release, the reaction is carried out at room temperature, and no refrigerator is required for cooling, which can greatly reduce the energy consumption. If the industrial electricity price is 1 yuan / degree, the energy consumption cost of the traditional pinene hydration reaction > 264, while the energy consumption cost of the new process is only 5.5 - 16.5 yuan.

[0019] 2. The mass yield of the synthetic terpin hydrate from turpentine oil in the present invention can reach 110%, and the content of 1,8-terpinol is 98%, as shown in the appendix Figure 1 . Moreover, when the high-efficiency emulsifier of the present invention is added to the hydration reaction, its dosage is less than 1‰. The obtained terpin hydrate does not need to be neutralized with alkali, and the acidic water can be reused, with almost no waste water discharge.

[0020] 3. The hydration reaction tank of the present invention can use IBC ton barrels, with less equipment investment. There is no need to build a special reaction platform, and it has good site adaptability. If n ICB barrels are grouped into 1# - 10#, starting from the first day of production, n barrels in the 1# group are fed with materials, and so on. On the 10th day, n barrels in the 10# group are fed with materials; then on the 11th day, after separating the terpin hydrate products in the n barrels of the 1# group, continue to feed materials, and so on. On the 20th day, the n barrels in the 10# group are discharged. In this way, it can ensure that at least 200 kg / barrel × n barrels = 200 × n kg of terpin hydrate products are produced every day.

[0021] 4. The isomerization by-products of the turpentine hydration reaction in the present invention can be reused as raw materials, that is, the by-products of the previous batch can be used as raw materials together with the turpentine oil of this batch. Different from the sulfuric acid method, the catalyst of this new process can catalyze isomerization by-products such as limonene, terpinene, and isolimonene to continue to react with water to synthesize terpin hydrate.

[0022] 5. For the dehydration reaction of the terpin hydrate in the present invention, the GC content of terpineol in the product can reach 90%, and the selectivity of terpineol can reach 91.1%, as shown in the appendix Figure 2 . Appendix Figure 2 In the gas chromatogram of the appendix, the three main peaks from left to right are β-terpineol, α-terpineol, and γ-terpineol, and their GC contents are 19.1%, 51.2%, and 19.7% respectively. Since the content of terpineol in the dehydration product ≥ 90%, it can be directly used as a fragrance, as shown in the appendix Figure 2 .

[0023] 6. In the present invention, by adding the dehydration reaction product of terpin hydrate back into the distillation kettle and adding hydrogen-type β-zeolite, the remaining terpin hydrate is further dehydrated to obtain terpineol, thereby improving the yield and purity of terpineol. The purity of the obtained terpineol can reach 93.5%, as shown in the appendix Figure 3 . Appendix Figure 3 In the gas chromatogram of the appendix, the three main peaks from left to right are β-terpineol, α-terpineol, and γ-terpineol, and their GC contents are 14.0%, 60.1%, and 19.4% respectively. For the same-specification terpineol sold on the market (purified by vacuum fractional distillation), the contents of the three isomers are 2.7% for β-terpineol, 70.1% for α-terpineol, and 20.7% for γ-terpineol, and the total GC content of terpineol is 93.5%, as shown in the appendix Figure 4 . From the appendixFigure 4 It can be seen that for the terpineol purified by the vacuum fractional distillation method, the content of β-terpineol is only 2.7%. This is because the boiling points of β-terpineol and the by-product fenchol are close, and it is very difficult to separate them using a distillation column. During vacuum fractional distillation, they almost distill out together. Attached Figure 4 Compared with Attached Figure 3 more than 80% of β-terpineol is lost. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is the GC chromatogram of the synthesized 1,8-terpinediol;

[0025] Figure 2 is the GC chromatogram of the terpineol prepared by dehydrating terpin hydrate;

[0026] Figure 3 is the GC chromatogram of the terpineol obtained by secondary distillation;

[0027] Figure 4 is the GC chromatogram of the commercially available terpineol obtained by vacuum fractional distillation. DETAILED DESCRIPTION OF THE INVENTION

[0028] Now, various exemplary embodiments of the present invention will be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, characteristics, and implementation schemes of the present invention.

[0029] It should be understood that the terms used in the present invention are only for describing specific embodiments and are not used to limit the present invention. Additionally, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded from the range.

[0030] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein can also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0031] Without departing from the scope or spirit of the present invention, various improvements and changes can be made to the specific embodiments of the specification of the present invention, which will be obvious to those skilled in the art. Other embodiments obtained from the specification of the present invention will be obvious to those skilled in the art. The specification and examples of this application are merely exemplary.

[0032] Regarding the terms "comprising", "including", "having", "containing", etc. used herein, they are all open-ended terms, meaning including but not limited to.

[0033] Analysis and testing methods for example or control sample

[0034] Analysis instrument: Aglient 7890A gas chromatograph, Agilent Technologies, USA; Chromatographic column: AT-35, fused silica capillary column (60m × 0.25mm × 0.25μm). GC analysis conditions: Carrier gas, high-purity nitrogen; Program temperature rise: 70°C (2 min), rising to 150°C at 50°C / min, staying for 3 min, then rising to 230°C at 30°C / min, staying for 40 min; Injection port temperature: 250°C, total flow rate 130.5 ml / min, split ratio 50:1, septum purge 3 ml / min; FID detection, detector temperature: 250°C, hydrogen flow rate 40 ml / min, air 450 ml / min, nitrogen purge, 25 ml / min. Injection volume 0.2 μl.

[0035] Example 1

[0036] A green production process for synthesizing 1,8-terpineol and dehydrating it to prepare perfume-grade terpineol, comprising the following steps:

[0037] (1) Hydration reaction: Turpentine (pinene content ≥ 85%), water, α-hydroxy acid composite catalyst and emulsifier are added to the reaction tank according to a mass ratio of 100:100:50:0.05, start stirring, the reaction temperature is 5 - 10°C, and the reaction time is 10 days; The α-hydroxy acid composite catalyst is composed of α-hydroxy acid and phosphoric acid, and their mass ratio is 3:37; The α-hydroxy acid is tartaric acid; The order of adding the raw materials to the hydration reaction tank is water, catalyst, and turpentine in sequence.

[0038] (2) Centrifugal separation: After the hydration reaction is completed, the crude hydrated terpineol in the reaction tank is taken out and put into a centrifuge for separation at a speed of 800 r / min and a filter screen pore size of 1000 meshes, and the centrifugate is collected; Then add water with a mass of 10% of the hydrated terpineol, wash the hydrated terpineol and separate it with a centrifuge, repeat 3 times, and combine the centrifugates.

[0039] (3) Acid water recovery: Let the centrifugate in step (3) stand for layering. The upper layer is a by-product containing isomers such as limonene, terpinene, and terpinolene, and the lower layer is acid water. Return the acid water to the reaction tank.

[0040] (4) By-product recovery: After measuring the by-product obtained in step (3), add it to the reaction tank together with turpentine as the raw material for the next hydration reaction.

[0041] (5) Dehydration reaction: Put the hydrated terpineol separated in step (2) into a dehydration reaction kettle equipped with an oil-water separator, add water twice its mass and tartaric acid at 0.5‰ of its mass, control the temperature at 100°C - 105°C, and react until no terpineol distills out.

[0042] (6) Secondary distillation: Put the dehydrated product of the hydrated terpineol in step (5) into a distillation kettle equipped with an oil-water separator, add water twice its mass, and add β-molecular sieve at 2.5% of its mass. Heat to boiling, collect the crude terpineol distilled out in the first 10 minutes, and purify it by vacuum fractional distillation; continue distilling until no terpineol distills out, and collect it as perfume-grade terpineol; the hydrogen-type β-molecular sieve has a silica-alumina ratio of 28 and a particle size of 5 μm.

[0043] The emulsifier described in step (1) includes the following raw materials in terms of mass percentage:

[0044] Sophorolipid 32.1%, N-methyl-N,N-dialkyl chitosan quaternary ammonium salt 17.0%, polyglycerol fatty acid ester 11.2%, sodium citrate 10.2%, sodium gluconate 6.5%, nano-silica 4.3%, and the balance is deionized water;

[0045] The preparation method of the emulsifier includes the following steps:

[0046] 1) Add sophorolipid and N-methyl-N,N-dialkyl chitosan quaternary ammonium salt to the reaction kettle, control the temperature at 50 - 54°C, and mix at a rotation speed of 200 r / min for 25 minutes to obtain mixture a;

[0047] 2) Add sodium citrate and sodium gluconate to the mixture a prepared in step 1), then control the temperature at 56 - 60°C, and then adjust the pH to 6.2 using food-grade citric acid to obtain mixture b;

[0048] 3) Add nano-silica to the mixture b prepared in step 2), and then treat it under the conditions of an ultrasonic power of 250 W and a frequency of 38 kHz for 14 minutes to obtain mixture c;

[0049] 4) Add polyglycerol fatty acid ester and deionized water to the mixture c obtained in step 3), and then stir at a speed of 1400 r / min for 9 min to obtain an emulsifier.

[0050] The vacuum fractional distillation described in step (6) is specifically operated as follows:

[0051] S1: First, discharge the air in the distillation column to make the vacuum degree in the distillation column ≤ -0.10 MPa;

[0052] S2: Transfer the crude terpineol product in step (6) to the bottom of the distillation column;

[0053] S3: Heat to keep the bottom temperature of the column at 110 - 120 °C and the top temperature at 90 - 95 °C, reflux for 1.5 h, with a reflux ratio of 12:1, and collect dipentene;

[0054] S4: Increase the temperature to keep the bottom temperature of the column at 130 - 140 °C and the top temperature at 95 - 105 °C, with a reflux ratio of 18:1, and collect terpineol;

[0055] After the hydration reaction, the yield of hydrated terpin diol is 110% and the purity is 98%, see the appendix Figure 1 ; After the dehydration reaction, the GC content of terpineol in the product is 90.0%, see the appendix Figure 2 ; After the secondary distillation, the GC content of terpineol is 93.5%, see the appendix Figure 3 .

[0056] Example 2

[0057] A green production process for synthesizing 1,8 - terpin diol and dehydrating it to prepare perfume - grade terpineol, including the following steps:

[0058] (1) Hydration reaction: Add turpentine (pinene content ≥ 85%), water, α - hydroxy acid composite catalyst, and emulsifier (prepared by the same process as in Example 1) to the reaction tank according to a mass ratio of 100:100:80:0.05, start stirring, with the reaction temperature at 25 - 30 °C and the reaction time at 7 days; the α - hydroxy acid composite catalyst consists of α - hydroxy acid and phosphoric acid, and their mass ratio is 7:40; the α - hydroxy acid is tartaric acid; the order of adding the raw materials to the hydration reaction tank is water, catalyst, and turpentine in sequence.

[0059] (2) Centrifugal separation: After the hydration reaction, take out the crude hydrated terpin diol in the reaction tank, put it into a centrifuge for separation at a speed of 1000 r / min and a filter screen pore size of 800 mesh, and collect the centrifugate; then add water with a mass of 10% of the hydrated terpin diol, wash the hydrated terpin diol and separate it with a centrifuge, repeat 3 times, and combine the centrifugates.

[0060] (3) Acid water recovery: Let the centrifugate from step (3) stand for layering. The upper layer is a by-product containing isomers such as limonene, terpinene, and terpinolene, and the lower layer is acid water. Return the acid water to the reaction tank.

[0061] (4) By-product recovery: After measuring the by-product obtained in step (3), add it together with turpentine as raw materials for the next hydration reaction into the reaction tank.

[0062] (5) Dehydration reaction: Put the hydrated terpin diol separated in step (2) into a dehydration reaction kettle equipped with an oil-water separator, add water twice its mass and tartaric acid at 0.3‰ of its mass, control the temperature at 100°C - 105°C, and react until no terpineol is distilled out.

[0063] (6) Secondary distillation: Put the dehydrated product of the hydrated terpin diol in step (5) into a distillation kettle equipped with an oil-water separator, add water twice its mass, and add β-molecular sieve at 2.5% of its mass. Heat to boiling, collect the crude terpineol distilled out in the first 10 min, and purify it by vacuum fractional distillation (the same vacuum fractional distillation method as in Example 1); continue distilling until no terpineol is distilled out, and collect it as perfume-grade terpineol; the hydrogen-type β-molecular sieve has a silica-alumina ratio of 28 and a particle size of 5 μm.

[0064] After the hydration reaction is completed, the yield of hydrated terpin diol is 105%; after the dehydration reaction is completed, the GC content of terpineol in the product is 90.5%; after secondary distillation, the GC content of terpineol is 93.2%.

[0065] Example 3

[0066] A green production process for synthesizing 1,8-terpin diol and dehydrating it to prepare perfume-grade terpineol includes the following steps:

[0067] (1) Hydration reaction: Add turpentine (pinene content ≥ 85%), water, α-hydroxy acid composite catalyst, and emulsifier (prepared by the same process as in Example 1) to the reaction tank according to a mass ratio of 100:100:80:0.05. Start stirring, the reaction temperature is 30 - 35°C, and the reaction time is 7 days; the α-hydroxy acid composite catalyst is composed of α-hydroxy acid and phosphoric acid, and their mass ratio is 7:40; the α-hydroxy acid is citric acid; the order of adding the raw materials to the hydration reaction tank is water, catalyst, and turpentine in sequence.

[0068] (2) Centrifugal separation: After the hydration reaction is completed, take out the crude hydrated terpin diol in the reaction tank, put it into a centrifuge for separation at a speed of 1000 r / min and a filter screen pore size of 800 mesh, and collect the centrifugate; then add water at 10% of the mass of the hydrated terpin diol, wash the hydrated terpin diol and separate it with a centrifuge, repeat 3 times, and combine the centrifugates.

[0069] (3) Acid water recovery: Let the centrifugate from step (3) stand for layering. The upper layer is the by-product containing isomers such as limonene, terpinene, and terpinolene, and the lower layer is acid water. The acid water is returned to the reaction tank.

[0070] (4) By-product recovery: After measuring the by-product obtained in step (3), it is added to the reaction tank together with turpentine as the raw material for the next hydration reaction.

[0071] (5) Dehydration reaction: Put the hydrated terpineol separated in step (2) into a dehydration reaction kettle equipped with an oil-water separator, add water twice its mass and citric acid 0.3‰ of its mass, control the temperature at 100 °C - 105 °C, and react until no terpineol is distilled out.

[0072] (6) Secondary distillation: Put the dehydrated product of the hydrated terpineol in step (5) into a distillation kettle equipped with an oil-water separator, add water twice its mass, and add β-molecular sieve 2.5% of its mass. Heat to boiling, collect the crude terpineol distilled out in the first 10 min, and purify it by the vacuum fractional distillation method (the same as the vacuum fractional distillation method in Example 1); continue distilling until no terpineol is distilled out, and collect it as perfume-grade terpineol; the hydrogen-type β-molecular sieve has a silica-alumina ratio of 28 and a particle size of 5 μm.

[0073] After the hydration reaction is completed, the yield of hydrated terpineol is 110%; after the dehydration reaction is completed, the GC content of terpineol in the product is 91.7%; after secondary distillation, the GC content of terpineol is 93.8%.

[0074] Example 4

[0075] A green production process for synthesizing 1,8-terpineol and dehydrating it to prepare perfume-grade terpineol includes the following steps:

[0076] (1) Hydration reaction: Add turpentine (pinene content ≥ 85%), water, α-hydroxy acid composite catalyst, and emulsifier (prepared by the same process as in Example 1) to the reaction tank according to a mass ratio of 100:100:100:0.05. Start stirring, the reaction temperature is 30 - 35 °C, and the reaction time is 5 days; the α-hydroxy acid composite catalyst is composed of α-hydroxy acid and phosphoric acid, and their mass ratio is 7:30; the α-hydroxy acid is citric acid; the order of adding the raw materials to the hydration reaction tank is water, catalyst, and turpentine in sequence.

[0077] (2) Centrifugal separation: After the hydration reaction is completed, take out the crude hydrated terpineol in the reaction tank, put it into a centrifuge for separation, the rotation speed is 1000 r / min, the filter screen pore size is 800 mesh, and collect the centrifugate; then add water 10% of the mass of the hydrated terpineol, wash the hydrated terpineol and separate it with a centrifuge, repeat 3 times, and combine the centrifugates.

[0078] (3) Acid water recovery: Let the centrifugate from step (3) stand for layering. The upper layer is a by-product containing isomers such as limonene, terpinene, and terpinolene, and the lower layer is acid water. Return the acid water to the reaction tank.

[0079] (4) By-product recovery: After measuring the by-product obtained in step (3), add it together with turpentine as the raw material for the next hydration reaction into the reaction tank.

[0080] (5) Dehydration reaction: Put the hydrated terpin diol separated in step (2) into a dehydration reaction kettle equipped with an oil-water separator, add water twice its mass and citric acid at 0.3‰ of its mass, control the temperature at 100°C - 105°C, and react until no terpineol distills out.

[0081] (6) Secondary distillation: Put the dehydrated product of the hydrated terpin diol in step (5) into a distillation kettle equipped with an oil-water separator, add water twice its mass, and add β-molecular sieve at 2.5% of its mass. Heat to boiling, collect the crude terpineol distilled out in the first 10 min, and purify it by vacuum fractional distillation (the same vacuum fractional distillation method as in Example 1); continue distilling until no terpineol distills out, and collect it as perfume-grade terpineol; the hydrogen-type β-molecular sieve has a silica-alumina ratio of 28 and a particle size of 5 μm.

[0082] After the hydration reaction, the yield of hydrated terpin diol is 113%; after the dehydration reaction, the GC content of terpineol in the product is 90.8%; after secondary distillation, the GC content of terpineol is 93.9%.

[0083] Example 5

[0084] A green production process for synthesizing 1,8-terpin diol and dehydrating it to prepare perfume-grade terpineol includes the following steps:

[0085] (1) Hydration reaction: Add turpentine (pinene content ≥ 85%), water, α-hydroxy acid composite catalyst, and emulsifier (prepared by the same process as in Example 1) to the reaction tank according to a mass ratio of 100:150:100:0.03. Start stirring, the reaction temperature is 35 - 39°C, and the reaction time is 3 days; the α-hydroxy acid composite catalyst is composed of α-hydroxy acid and phosphoric acid, and their mass ratio is 7:30; the α-hydroxy acid is citric acid; the order of adding the raw materials to the hydration reaction tank is water, catalyst, and turpentine in sequence.

[0086] (2) Centrifugal separation: After the hydration reaction, take out the crude hydrated terpin diol in the reaction tank, put it into a centrifuge for separation at a speed of 1000 r / min and a filter screen aperture of 800 mesh, and collect the centrifugate; then add water at 10% of the mass of the hydrated terpin diol, wash the hydrated terpin diol and separate it with a centrifuge, repeat 3 times, and combine the centrifugates.

[0087] (3) Acid water recovery: Let the centrifugate in step (3) stand for layering. The upper layer is a by-product containing isomers such as limonene, terpinene, and terpinolene, and the lower layer is acid water. Return the acid water to the reaction tank.

[0088] (4) By-product recovery: After measuring the by-product obtained in step (3), add it to the reaction tank together with turpentine as the raw material for the next hydration reaction.

[0089] (5) Dehydration reaction: Put the hydrated terpineol separated in step (2) into a dehydration reaction kettle equipped with an oil-water separator, add water twice its mass and citric acid 0.3‰ of its mass, control the temperature at 100 °C - 105 °C, and react until no terpineol is distilled out.

[0090] (6) Secondary distillation: Put the dehydrated product of the hydrated terpineol in step (5) into a distillation kettle equipped with an oil-water separator, add water twice its mass, and add β-molecular sieve 2.5% of its mass. Heat to boiling, collect the crude terpineol distilled out in the first 10 min, and purify it by vacuum fractional distillation (the same vacuum fractional distillation method as in Example 1); continue distilling until no terpineol is distilled out, and collect it as perfume-grade terpineol; the hydrogen-type β-molecular sieve has a silica-alumina ratio of 28 and a particle size of 5 μm.

[0091] After the hydration reaction is completed, the yield of hydrated terpineol is 118%; after the dehydration reaction is completed, the GC content of terpineol in the product is 90.5%; after secondary distillation, the GC content of terpineol is 93.8%.

[0092] Example 6

[0093] A green production process for synthesizing 1,8-terpineol and dehydrating it to prepare perfume-grade terpineol includes the following steps:

[0094] (1) Hydration reaction: Add turpentine (pinene content ≥ 85%), water, α-hydroxy acid composite catalyst, and emulsifier (prepared by the same process as in Example 1) to the reaction tank according to a mass ratio of 100:150:100:0.01. Start stirring, and the reaction temperature is 30 - 35 °C and the reaction time is 7 days; the α-hydroxy acid composite catalyst is composed of α-hydroxy acid and phosphoric acid, and their mass ratio is 1:2; the α-hydroxy acid is lactic acid; the order of adding the raw materials to the hydration reaction tank is water, catalyst, and turpentine in sequence.

[0095] (2) Centrifugal separation: After the hydration reaction is completed, take out the crude hydrated terpineol in the reaction tank, put it into a centrifuge for separation at a speed of 1000 r / min and a filter screen aperture of 800 meshes, and collect the centrifugate; then add water 10% of the mass of the hydrated terpineol, wash the hydrated terpineol and separate it with a centrifuge, repeat 3 times, and combine the centrifugates.

[0096] (3) Acid water recovery: Let the centrifugate from step (3) stand for layering. The upper layer is the by-product containing isomers such as limonene, terpinene, and terpinolene, and the lower layer is the acid water. Return the acid water to the reaction tank.

[0097] (4) By-product recovery: After measuring the by-product obtained in step (3), add it to the reaction tank together with turpentine as the raw material for the next hydration reaction.

[0098] (5) Dehydration reaction: Put the hydrated terpineol separated in step (2) into a dehydration reaction kettle equipped with an oil-water separator, add water twice its mass and citric acid 0.3‰ of its mass, control the temperature at 100 °C - 105 °C, and react until no terpineol is distilled out.

[0099] (6) Secondary distillation: Put the dehydrated product of the hydrated terpineol in step (5) into a distillation kettle equipped with an oil-water separator, add water twice its mass, and add β-molecular sieve 2.5% of its mass. Heat to boiling, collect the crude terpineol distilled out in the first 10 min, and purify it by vacuum fractional distillation (the same vacuum fractional distillation method as in Example 1); continue distillation until no terpineol is distilled out, and collect it as perfume-grade terpineol; the hydrogen-type β-molecular sieve has a silica-alumina ratio of 28 and a particle size of 5 μm.

[0100] After the hydration reaction is completed, the yield of hydrated terpineol is 109%; after the dehydration reaction is completed, the GC content of terpineol in the product is 90.5%; after secondary distillation, the GC content of terpineol is 93.8%.

[0101] Example 7

[0102] A green production process for synthesizing 1,8-terpineol and dehydrating it to prepare perfume-grade terpineol includes the following steps:

[0103] (1) Hydration reaction: Add turpentine (pinene content ≥ 85%), water, α-hydroxy acid composite catalyst, and emulsifier (prepared by the same process as in Example 1) to the reaction tank according to a mass ratio of 100:150:100:0.01. Start stirring, the reaction temperature is 30 - 35 °C, and the reaction time is 7 days; the α-hydroxy acid composite catalyst is composed of α-hydroxy acid and phosphoric acid, and their mass ratio is 1:5; the α-hydroxy acid is glycolic acid; the order of adding the raw materials to the hydration reaction tank is water, catalyst, and turpentine in sequence.

[0104] (2) Centrifugal separation: After the hydration reaction is completed, take out the crude hydrated terpineol in the reaction tank, put it into a centrifuge for separation at a speed of 1000 r / min and a filter screen pore size of 800 mesh, and collect the centrifugate; then add water 10% of the mass of the hydrated terpineol, wash the hydrated terpineol and separate it with a centrifuge, repeat 3 times, and combine the centrifugates.

[0105] (3) Acid water recovery: Let the centrifugate in step (3) stand for stratification. The upper layer is a by-product containing isomers such as limonene, terpinene, and terpinolene, and the lower layer is acid water. Return the acid water to the reaction tank.

[0106] (4) By-product recovery: After measuring the by-product obtained in step (3), add it to the reaction tank together with turpentine as the raw material for the next hydration reaction.

[0107] (5) Dehydration reaction: Put the hydrated terpineol separated in step (2) into a dehydration reaction kettle equipped with an oil-water separator, add water twice its mass and citric acid at 0.3‰ of its mass, control the temperature at 100°C - 105°C, and react until no terpineol is distilled out.

[0108] (6) Secondary distillation: Put the dehydrated product of the hydrated terpineol in step (5) into a distillation kettle equipped with an oil-water separator, add water twice its mass, and add β-molecular sieve at 2.5% of its mass. Heat to boiling, collect the crude terpineol distilled out in the first 10 min, and purify it by vacuum fractional distillation (the same vacuum fractional distillation method as in Example 1); continue distillation until no terpineol is distilled out, and collect it as perfume-grade terpineol; the hydrogen-type β-molecular sieve has a silica-alumina ratio of 28 and a particle size of 5 μm.

[0109] After the hydration reaction, the yield of hydrated terpineol is 109%; after the dehydration reaction, the GC content of terpineol in the product is 90.5%; after secondary distillation, the GC content of terpineol is 93.8%.

[0110] Example 8

[0111] A green production process for synthesizing 1,8-terpineol and dehydrating it to prepare perfume-grade terpineol, comprising the following steps:

[0112] (1) Hydration reaction: Add turpentine (pinene content ≥ 85%), water, α-hydroxy acid composite catalyst, and emulsifier (prepared by the same process as in Example 1) to the reaction tank according to a mass ratio of 100:150:100:0.01. Start stirring, the reaction temperature is 30 - 35°C, and the reaction time is 5 days; the α-hydroxy acid composite catalyst consists of α-hydroxy acid and phosphoric acid, and their mass ratio is 1:3; the α-hydroxy acid is mandelic acid; the order of adding the raw materials to the hydration reaction tank is water, catalyst, and turpentine.

[0113] (2) Centrifugal separation: After the hydration reaction, take out the crude hydrated terpineol in the reaction tank, put it into a centrifuge for separation at a speed of 1000 r / min and a filter screen pore size of 800 mesh, and collect the centrifugate; then add water at 10% of the mass of the hydrated terpineol, wash the hydrated terpineol and separate it with a centrifuge, repeat 3 times, and combine the centrifugates.

[0114] (3) Acid water recovery: Let the centrifugate from step (3) stand for layering. The upper layer is a by-product containing isomers such as limonene, terpinene, and terpinolene, and the lower layer is acid water. The acid water is returned to the reaction tank.

[0115] (4) By-product recovery: After measuring the by-product obtained in step (3), it is added to the reaction tank together with turpentine as a raw material for the next hydration reaction.

[0116] (5) Dehydration reaction: Put the hydrated terpin diol separated in step (2) into a dehydration reaction kettle equipped with an oil-water separator, add water twice its mass and citric acid 0.3‰ of its mass, control the temperature at 100 °C - 105 °C, and react until no terpineol is distilled out.

[0117] (6) Secondary distillation: Put the dehydrated product of the hydrated terpin diol in step (5) into a distillation kettle equipped with an oil-water separator, add water twice its mass, and add β-molecular sieve 2.5% of its mass. Heat to boiling, collect the crude terpineol distilled out in the first 10 min, and purify it by vacuum fractional distillation method (the same vacuum fractional distillation method as in Example 1); continue distillation until no terpineol is distilled out, and collect it as perfume-grade terpineol; the hydrogen-type β-molecular sieve has a silica-alumina ratio of 28 and a particle size of 5 μm.

[0118] After the hydration reaction is completed, the yield of hydrated terpin diol is 113%; after the dehydration reaction is completed, the GC content of terpineol in the product is 90.6%; after secondary distillation, the GC content of terpineol is 93.8%.

[0119] Example 9

[0120] A green production process for synthesizing 1,8-terpin diol and dehydrating it to prepare perfume-grade terpineol, comprising the following steps:

[0121] (1) Hydration reaction: Add turpentine (pinene content ≥ 85%), water, α-hydroxy acid composite catalyst, and emulsifier (prepared by the same process as in Example 1) to the reaction tank according to a mass ratio of 100:150:100:0.01. Start stirring, the reaction temperature is 30 - 35 °C, and the reaction time is 7 days; the α-hydroxy acid composite catalyst is composed of α-hydroxy acid and phosphoric acid, and their mass ratio is 1:4; the α-hydroxy acid is malic acid; the order of adding the raw materials to the hydration reaction tank is water, catalyst, and turpentine in sequence.

[0122] (2) Centrifugal separation: After the hydration reaction is completed, take out the crude hydrated terpin diol in the reaction tank, put it into a centrifuge for separation at a speed of 1000 r / min and a filter screen pore size of 800 mesh, and collect the centrifugate; then add water 10% of the mass of the hydrated terpin diol, wash the hydrated terpin diol and separate it with a centrifuge, repeat 3 times, and combine the centrifugates.

[0123] (3) Acid water recovery: Let the centrifugate from step (3) stand for layering. The upper layer is a by-product containing isomers such as limonene, terpinene, and terpinolene, and the lower layer is acid water. Return the acid water to the reaction tank.

[0124] (4) By-product recovery: After measuring the by-product obtained in step (3), add it to the reaction tank together with turpentine as the raw material for the next hydration reaction.

[0125] (5) Dehydration reaction: Put the hydrated terpineol separated in step (2) into a dehydration reaction kettle equipped with an oil-water separator, add water twice its mass and citric acid 0.3‰ of its mass, control the temperature at 100°C - 105°C, and react until no terpineol is distilled out.

[0126] (6) Secondary distillation: Put the dehydrated product of the hydrated terpineol in step (5) into a distillation kettle equipped with an oil-water separator, add water twice its mass, and add β-molecular sieve 2.5% of its mass. Heat to boiling, collect the crude terpineol distilled out in the first 10 min, and purify it by vacuum fractional distillation (the same vacuum fractional distillation method as in Example 1); continue distillation until no terpineol is distilled out, and collect it as perfume-grade terpineol; the hydrogen-type β-molecular sieve has a silica-alumina ratio of 28 and a particle size of 5 μm.

[0127] After the hydration reaction is completed, the yield of hydrated terpineol is 105%; after the dehydration reaction is completed, the GC content of terpineol in the product is 90.1%; after secondary distillation, the GC content of terpineol is 93.2%.

[0128] Example 10

[0129] A green production process for synthesizing 1,8-terpineol and dehydrating it to prepare perfume-grade terpineol, comprising the following steps:

[0130] (1) Hydration reaction: Add turpentine (pinene content ≥ 85%), water, α-hydroxy acid composite catalyst, and emulsifier (prepared by the same process as in Example 1) to the reaction tank according to a mass ratio of 100:150:100:0.01. Start stirring, the reaction temperature is 30 - 39°C, and the reaction time is 6 days; the α-hydroxy acid composite catalyst is composed of α-hydroxy acid and phosphoric acid, and their mass ratio is 1:2; the α-hydroxy acid is gluconic acid; the order of adding the raw materials to the hydration reaction tank is water, catalyst, and turpentine in sequence.

[0131] (2) Centrifugal separation: After the hydration reaction is completed, take out the crude hydrated terpineol in the reaction tank, put it into a centrifuge for separation at a speed of 1000 r / min and a filter screen aperture of 800 mesh, and collect the centrifugate; then add water 10% of the mass of the hydrated terpineol, wash the hydrated terpineol and separate it with a centrifuge, repeat 3 times, and combine the centrifugates.

[0132] (3) Acid water recovery: Let the centrifugate from step (3) stand for layering. The upper layer is a by-product containing isomers such as limonene, terpinene, and terpinolene, and the lower layer is acid water. The acid water is returned to the reaction tank.

[0133] (4) By-product recovery: After measuring the by-product obtained in step (3), it is added to the reaction tank together with turpentine as a raw material for the next hydration reaction.

[0134] (5) Dehydration reaction: Put the hydrated terpin diol separated in step (2) into a dehydration reaction kettle equipped with an oil-water separator, add water twice its mass and citric acid at 0.3‰ of its mass, control the temperature at 100 °C to 105 °C, and react until no terpineol distills out.

[0135] (6) Secondary distillation: Put the dehydrated product of the hydrated terpin diol in step (5) into a distillation kettle equipped with an oil-water separator, add water twice its mass, and add β-molecular sieve at 2.5% of its mass. Heat to boiling, collect the crude terpineol distilled out in the first 10 min, and purify it by vacuum fractional distillation (the same vacuum fractional distillation method as in Example 1); continue distilling until no terpineol distills out, and collect it as perfume-grade terpineol; the hydrogen-type β-molecular sieve has a silica-alumina ratio of 28 and a particle size of 5 μm.

[0136] After the hydration reaction is completed, the yield of hydrated terpin diol is 115%; after the dehydration reaction is completed, the GC content of terpineol in the product is 90.1%; after secondary distillation, the GC content of terpineol is 93.5%.

[0137] Example 11

[0138] A green production process for synthesizing 1,8-terpin diol and dehydrating it to prepare perfume-grade terpineol, comprising the following steps:

[0139] (1) Hydration reaction: Add turpentine (pinene content ≥ 85%), water, α-hydroxy acid composite catalyst, and emulsifier (prepared by the same process as in Example 1) to the reaction tank according to a mass ratio of 100:150:100:0.01. Start stirring, the reaction temperature is 30 - 39 °C, and the reaction time is 7 days; the α-hydroxy acid composite catalyst is composed of α-hydroxy acid and phosphoric acid, and their mass ratio is 1:10; the α-hydroxy acid is lactic acid; the order of adding the raw materials to the hydration reaction tank is water, catalyst, and turpentine in sequence.

[0140] (2) Centrifugal separation: After the hydration reaction is completed, take out the crude hydrated terpin diol in the reaction tank, put it into a centrifuge for separation, with a rotation speed of 1000 r / min and a filter screen pore size of 800 mesh, and collect the centrifugate; then add water at 10% of the mass of the hydrated terpin diol, wash the hydrated terpin diol and separate it with a centrifuge, repeat 3 times, and combine the centrifugates.

[0141] (3) Acid water recovery: Let the centrifugate from step (3) stand for layering. The upper layer is a by-product containing isomers such as limonene, terpinene, and terpinolene, and the lower layer is acid water. The acid water is returned to the reaction tank.

[0142] (4) By-product recovery: After measuring the by-product obtained in step (3), it is added to the reaction tank together with turpentine as the raw material for the next hydration reaction.

[0143] (5) Dehydration reaction: Put the hydrated terpineol separated in step (2) into a dehydration reaction kettle equipped with an oil-water separator, add water twice its mass and citric acid at 0.3‰ of its mass, control the temperature at 100 °C to 105 °C, and react until no terpineol is distilled out.

[0144] (6) Secondary distillation: Put the dehydrated product of the hydrated terpineol in step (5) into a distillation kettle equipped with an oil-water separator, add water twice its mass, and add β-molecular sieve at 2.5% of its mass. Heat to boiling, collect the crude terpineol distilled out in the first 10 min, and purify it by vacuum fractional distillation (the same vacuum fractional distillation method as in Example 1); continue distilling until no terpineol is distilled out, and collect it as perfume-grade terpineol; the hydrogen-type β-molecular sieve has a silica-alumina ratio of 28 and a particle size of 5 μm.

[0145] After the hydration reaction is completed, the yield of hydrated terpineol is 109%; after the dehydration reaction is completed, the GC content of terpineol in the product is 90.1%; after secondary distillation, the GC content of terpineol is 93.7%.

[0146] Example 12

[0147] A green production process for synthesizing 1,8-terpineol and dehydrating it to prepare perfume-grade terpineol includes the following steps:

[0148] (1) Hydration reaction: Add turpentine (pinene content ≥ 85%), water, α-hydroxy acid composite catalyst, and emulsifier (prepared by the same process as in Example 1) to the reaction tank according to a mass ratio of 100:150:100:0.05. Start stirring, the reaction temperature is 30 - 39 °C, and the reaction time is 10 days; the α-hydroxy acid composite catalyst is composed of α-hydroxy acid and boric acid, and their mass ratio is 10:1; the α-hydroxy acid is citric acid; the order of adding the raw materials to the hydration reaction tank is water, catalyst, and turpentine in sequence.

[0149] (2) Centrifugal separation: After the hydration reaction is completed, take out the crude hydrated terpineol in the reaction tank, put it into a centrifuge for separation at a speed of 1000 r / min and a filter screen aperture of 800 mesh, and collect the centrifugate; then add water at 10% of the mass of the hydrated terpineol, wash the hydrated terpineol and separate it with a centrifuge, repeat 3 times, and combine the centrifugates.

[0150] (3) Acid water recovery: Let the centrifugate from step (3) stand for layering. The upper layer is a by-product containing isomers such as limonene, terpinene, and terpinolene, and the lower layer is acid water. The acid water is returned to the reaction tank.

[0151] (4) By-product recovery: After measuring the by-product obtained in step (3), it is added to the reaction tank together with turpentine as a raw material for the next hydration reaction.

[0152] (5) Dehydration reaction: Put the hydrated terpin diol separated in step (2) into a dehydration reaction kettle equipped with an oil-water separator, add water twice its mass and citric acid at 0.3‰ of its mass, control the temperature at 100 °C - 105 °C, and react until no terpineol distills out.

[0153] (6) Secondary distillation: Put the dehydrated product of the hydrated terpin diol in step (5) into a distillation kettle equipped with an oil-water separator, add water twice its mass, and add β-molecular sieve at 2.5% of its mass. Heat to boiling, collect the crude terpineol distilled out in the first 10 minutes, and purify it by vacuum fractional distillation (the same vacuum fractional distillation method as in Example 1); continue distillation until no terpineol distills out, and collect it as perfume-grade terpineol; the hydrogen-type β-molecular sieve has a silica-alumina ratio of 28 and a particle size of 5 μm.

[0154] After the hydration reaction is completed, the yield of hydrated terpin diol is 115%; after the dehydration reaction is completed, the GC content of terpineol in the product is 90.1%; after secondary distillation, the GC content of terpineol is 93.5%.

[0155] Example 13

[0156] A green production process for synthesizing 1,8-terpin diol and dehydrating it to prepare perfume-grade terpineol, comprising the following steps:

[0157] (1) Hydration reaction: Add turpentine (pinene content ≥ 85%), water, α-hydroxy acid composite catalyst, and emulsifier (prepared by the same process as in Example 1) to the reaction tank according to a mass ratio of 100:100:100:0.05. Start stirring, the reaction temperature is 30 - 39 °C, and the reaction time is 10 days; the α-hydroxy acid composite catalyst is composed of α-hydroxy acid and boric acid, and their mass ratio is 10:1; the α-hydroxy acid is tartaric acid; the order of adding the raw materials to the hydration reaction tank is water, catalyst, and turpentine in sequence.

[0158] (2) Centrifugal separation: After the hydration reaction is completed, take out the crude hydrated terpin diol in the reaction tank, put it into a centrifuge for separation at a speed of 1000 r / min and a filter screen aperture of 800 meshes, and collect the centrifugate; then add water at 10% of the mass of the hydrated terpin diol, wash the hydrated terpin diol and separate it with a centrifuge, repeat 3 times, and combine the centrifugates.

[0159] (3) Acid water recovery: Let the centrifugate from step (3) stand for layering. The upper layer is a by-product containing isomers such as limonene, terpinene, and terpinolene, and the lower layer is acid water. Return the acid water to the reaction tank.

[0160] (4) By-product recovery: After measuring the by-product obtained in step (3), add it to the reaction tank together with turpentine as the raw material for the next hydration reaction.

[0161] (5) Dehydration reaction: Put the hydrated terpinol obtained by separation in step (2) into a dehydration reaction kettle equipped with an oil-water separator, add water twice its mass and tartaric acid at 0.3‰ of its mass, control the temperature at 100 °C - 105 °C, and react until no terpineol distills out.

[0162] (6) Secondary distillation: Put the dehydrated product of the hydrated terpinol in step (5) into a distillation kettle equipped with an oil-water separator, add water twice its mass, and add β-molecular sieve at 2.5% of its mass. Heat to boiling, collect the crude terpineol distilled out in the first 10 min, and purify it by vacuum fractional distillation (the same vacuum fractional distillation method as in Example 1); continue distilling until no terpineol distills out, and collect it as perfume-grade terpineol; the hydrogen-type β-molecular sieve has a silica-alumina ratio of 28 and a particle size of 5 μm.

[0163] After the hydration reaction is completed, the yield of hydrated terpinol is 116%; after the dehydration reaction is completed, the GC content of terpineol in the product is 90.5%; after secondary distillation, the GC content of terpineol is 93.7%.

[0164] Example 14

[0165] A green production process for synthesizing 1,8-terpinol and dehydrating it to prepare perfume-grade terpineol, comprising the following steps:

[0166] (1) Hydration reaction: Add turpentine (pinene content ≥ 85%), water, α-hydroxy acid composite catalyst, and emulsifier (prepared by the same process as in Example 1) to the reaction tank according to a mass ratio of 100:100:100:0.05. Start stirring, the reaction temperature is 30 - 39 °C, and the reaction time is 10 days; the α-hydroxy acid composite catalyst is composed of α-hydroxy acid and boric acid, and their mass ratio is 100:3; the α-hydroxy acid is citric acid; the order of adding the raw materials to the hydration reaction tank is water, catalyst, and turpentine in sequence.

[0167] (2) Centrifugal separation: After the hydration reaction is completed, take out the crude hydrated terpinol in the reaction tank, put it into a centrifuge for separation at a speed of 1000 r / min and a filter screen pore size of 800 mesh, and collect the centrifugate; then add water at 10% of the mass of the hydrated terpinol, wash the hydrated terpinol and separate it with a centrifuge, repeat 3 times, and combine the centrifugates.

[0168] (3) Acid water recovery: Let the centrifugate in step (3) stand for layering. The upper layer is a by-product containing isomers such as limonene, terpinene, and terpinolene, and the lower layer is acid water. The acid water is returned to the reaction tank.

[0169] (4) By-product recovery: After measuring the by-product obtained in step (3), it is added to the reaction tank together with turpentine as a raw material for the next hydration reaction.

[0170] (5) Dehydration reaction: Put the hydrated terpineol separated in step (2) into a dehydration reaction kettle equipped with an oil-water separator, add water twice its mass and citric acid at 0.3‰ of its mass, control the temperature at 100 °C - 105 °C, and react until no terpineol is distilled out.

[0171] (6) Secondary distillation: Put the dehydrated product of the hydrated terpineol in step (5) into a distillation kettle equipped with an oil-water separator, add water twice its mass, and add β-molecular sieve at 2.5% of its mass. Heat to boiling, collect the crude terpineol distilled out in the first 10 min, and purify it by vacuum fractional distillation (the same vacuum fractional distillation method as in Example 1); continue distilling until no terpineol is distilled out, and collect it as perfume-grade terpineol; the hydrogen-type β-molecular sieve has a silica-alumina ratio of 28 and a particle size of 5 μm.

[0172] After the hydration reaction is completed, the yield of hydrated terpineol is 117%; after the dehydration reaction is completed, the GC content of terpineol in the product is 90.5%; after secondary distillation, the GC content of terpineol is 93.7%.

[0173] Example 15

[0174] A green production process for synthesizing 1,8-terpineol and dehydrating it to prepare perfume-grade terpineol, comprising the following steps:

[0175] (1) Hydration reaction: Add turpentine (pinene content ≥ 85%), water, α-hydroxy acid composite catalyst, and emulsifier (prepared by the same process as in Example 1) to the reaction tank according to a mass ratio of 100:150:100:0.05. Start stirring, the reaction temperature is 30 - 39 °C, and the reaction time is 15 days; the α-hydroxy acid composite catalyst is composed of α-hydroxy acid and boric acid, and their mass ratio is 100:3; the α-hydroxy acid is mandelic acid; the order of adding the raw materials to the hydration reaction tank is water, catalyst, and turpentine in sequence.

[0176] (2) Centrifugal separation: After the hydration reaction is completed, the crude hydrated terpineol in the reaction tank is taken out and put into a centrifuge for separation at a speed of 1000 r / min and a filter screen pore size of 800 mesh, and the centrifugate is collected; then water accounting for 10% of the mass of the hydrated terpineol is added, the hydrated terpineol is washed and separated by a centrifuge, and this is repeated 3 times, and the centrifugates are combined.

[0177] (3) Acid water recovery: The centrifugate from step (3) is allowed to stand and separate into layers. The upper layer is a by-product containing isomers such as limonene, terpinene, and terpinolene, and the lower layer is acid water, which is returned to the reaction tank.

[0178] (4) By-product recovery: After the by-product obtained in step (3) is measured, it is added to the reaction tank together with turpentine as a raw material for the next hydration reaction.

[0179] (5) Dehydration reaction: The hydrated terpineol separated in step (2) is put into a dehydration reaction kettle equipped with an oil-water separator, and water twice its mass and citric acid 0.3‰ of its mass are added, and the temperature is controlled at 100°C - 105°C, and the reaction is carried out until no terpineol is distilled out.

[0180] (6) Secondary distillation: The dehydrated product of the hydrated terpineol in step (5) is put into a distillation kettle equipped with an oil-water separator, water twice its mass is added, and β-molecular sieve 2.5% of its mass is added, heated to boiling, and the crude terpineol distilled out in the first 10 min is collected and purified by vacuum fractional distillation (the same vacuum fractional distillation method as in Example 1); continue distillation until no terpineol is distilled out, and the product collected later is used as perfume-grade terpineol; the hydrogen-type β-molecular sieve has a silica-alumina ratio of 28 and a particle size of 5 μm.

[0181] After the hydration reaction is completed, the yield of hydrated terpineol is 115%; after the dehydration reaction is completed, the GC content of terpineol in the product is 90.4%; after secondary distillation, the GC content of terpineol is 93.8%.

[0182] Example 16

[0183] A green production process for synthesizing 1,8-terpineol and dehydrating it to prepare perfume-grade terpineol includes the following steps:

[0184] (1) Hydration reaction: Turpentine (pinene content ≥ 85%), water, an α-hydroxy acid composite catalyst, and an emulsifier (prepared by the same process as in Example 1) are added to the reaction tank in a mass ratio of 100:100:100:0.05, stirring is started, the reaction temperature is 30 - 39°C, and the reaction time is 10 days; the α-hydroxy acid composite catalyst is composed of α-hydroxy acid and boric acid, and their mass ratio is 100:3; the α-hydroxy acid is citric acid; the order of adding the raw materials to the hydration reaction tank is water, catalyst, and turpentine in sequence.

[0185] (2) Centrifugal separation: After the hydration reaction is completed, the crude hydrated terpineol in the reaction tank is taken out and put into a centrifuge for separation at a rotation speed of 1000 r / min and a filter screen pore size of 800 mesh, and the centrifugate is collected; then, water accounting for 10% of the mass of the hydrated terpineol is added, the hydrated terpineol is washed and separated by a centrifuge, and this is repeated 3 times, and the centrifugates are combined.

[0186] (3) Acid water recovery: The centrifugate from step (3) is allowed to stand for stratification. The upper layer is a by-product containing isomers such as limonene, terpinene, and terpinolene, and the lower layer is acid water, which is returned to the reaction tank.

[0187] (4) By-product recovery: After the by-product obtained in step (3) is measured, it is added to the reaction tank together with turpentine as a raw material for the next hydration reaction.

[0188] (5) Dehydration reaction: The hydrated terpineol separated in step (2) is put into a dehydration reaction kettle equipped with an oil-water separator, and water twice its mass and citric acid accounting for 0.3‰ of its mass are added. The temperature is controlled at 100 °C - 105 °C, and the reaction is carried out until no terpineol is distilled out.

[0189] (6) Secondary distillation: The dehydrated product of the hydrated terpineol in step (5) is put into a distillation kettle equipped with an oil-water separator, water twice its mass is added, and β-molecular sieve accounting for 2.5% of its mass is added. It is heated to boiling, and the crude terpineol distilled out in the first 10 min is collected and purified by the vacuum fractional distillation method (the same vacuum fractional distillation method as in Example 1); continue distilling until no terpineol is distilled out, and the product collected later is used as perfume-grade terpineol; the hydrogen-type β-molecular sieve has a silica-alumina ratio of 28 and a particle size of 5 μm.

[0190] After the hydration reaction is completed, the yield of hydrated terpineol is 117%; after the dehydration reaction is completed, the GC content of terpineol in the product is 90.5%; after secondary distillation, the GC content of terpineol is 93.7%.

[0191] Control Example 1

[0192] Comparative experiment. Phosphoric acid is used as the catalyst, and other reaction conditions are the same as in Example 1. After the hydration reaction is completed, the yield of hydrated terpineol is 5%.

[0193] Control Example 2

[0194] Comparative experiment. α-Hydroxy acid is used as the catalyst, and other reaction conditions are the same as in Example 1. After the hydration reaction is completed, the yield of hydrated terpineol is 0.

[0195] Control Example 3

[0196] Comparative experiment. Boric acid is used as the catalyst, and other reaction conditions are the same as in Example 1. After the hydration reaction is completed, the yield of hydrated terpineol is 0.

[0197] The above content is a further detailed description of the present invention in combination with specific / preferred embodiments, and it cannot be determined that the specific implementation of the present invention is only limited to these descriptions. For those of ordinary skill in the technical field to which the present invention pertains, without departing from the concept of the present invention, several alternatives or modifications can be made to these described embodiments, and these alternative or modified forms should all be regarded as falling within the protection scope of the present invention.

Claims

1. A green production process for synthesizing 1,8-terpene diol and dehydrating it to prepare perfume-grade terpineol, which includes a hydration reaction, centrifugal separation, acid water recovery, by-product recovery, dehydration reaction, and secondary distillation, and is characterized in that: The hydration reaction includes the following steps: turpentine, water, an α-hydroxy acid composite catalyst, and an emulsifier are added to a reaction tank in a mass ratio of 100:50-150:20-150:0.01-0.

5. Stirring is started at a rotation speed of 200-300 r / min, the reaction temperature is 5-40 °C, and the reaction time is 2-15 days; the α-hydroxy acid composite catalyst consists of an α-hydroxy acid and phosphoric acid or boric acid; the α-hydroxy acid consists of one or more of glycolic acid, lactic acid, mandelic acid, tartaric acid, malic acid, citric acid, gluconic acid, lactobionic acid; the raw materials are added to the hydration reaction tank in the order of water, catalyst, and turpentine.

2. The green production process for synthesizing 1,8-terpene diol and dehydrating it to prepare perfume-grade terpineol according to claim 1, characterized in that: The hydration reaction uses intermittent stirring, 2-6 times a day, each time for 1-5 minutes, with an interval of 6-12 hours each time.

3. The green production process for synthesizing 1,8-terpene diol and dehydrating it to prepare perfume-grade terpineol according to claim 2, characterized in that: The catalyst for the hydration reaction consists of an α-hydroxy acid and phosphoric acid, and their mass ratio is 1-50:

100.

4. The green production process for synthesizing 1,8-terpene diol and dehydrating it to prepare perfume-grade terpineol according to claim 2, characterized in that: The catalyst for the hydration reaction consists of an α-hydroxy acid and boric acid, and their mass ratio is 100:1-60.

5. The green production process for synthesizing 1,8-terpene diol and dehydrating it to prepare perfume-grade terpineol according to claim 4, characterized in that: The emulsifier is made from the following raw materials: sophorolipid, N-methyl-N,N-dialkyl chitosan quaternary ammonium salt, polyglycerol fatty acid ester, sodium citrate, sodium gluconate, nano-silica, and water.

6. The green production process for synthesizing 1,8-terpene diol and dehydrating it to prepare perfume-grade terpineol according to claim 1, characterized in that: The hydration reaction tank is an IBC ton barrel, with an inner liner made of high-density polyethylene, an outer frame formed by welding hot-dip galvanized steel pipes, a bottom tray cast from steel plates, plastic corner guards installed at the four bottom corners, and the diameter of the loading port is larger than the diameter of the stirring paddle.

7. The green production process for synthesizing 1,8-terpene diol and dehydrating it to prepare perfume-grade terpineol according to claim 1, characterized in that: After the hydration reaction is completed, the crude hydrate of terpine diol in the reaction tank is taken out and put into a centrifuge for separation at a rotation speed of 800-1000 r / min and a filter screen pore size of 800-1000 mesh, and the centrifugate is collected; then, water accounting for 10% of the mass of the hydrate of terpine diol is added, the hydrate of terpine diol is washed and separated by a centrifuge, and this is repeated 3 times, and the centrifugates are combined; the collected centrifugate is allowed to stand and separate into layers, with the upper layer being a by-product containing isomers such as limonene, terpinene, and terpinolene, and the lower layer being acid water; the obtained acid water is returned to the reaction tank; after the obtained by-product is metered, it is added to the reaction tank together with turpentine as a raw material for the next hydration reaction.

8. The green production process for synthesizing 1,8-terpene diol and dehydrating it to prepare perfume-grade terpineol according to claim 7, characterized in that: 1-10% of the catalyst needs to be replenished in the hydration reaction; the catalyst is phosphoric acid or α-hydroxycarboxylic acid.

9. The green production process for synthesizing 1,8-terpene diol and dehydrating it to prepare perfume-grade terpineol according to claim 1, characterized in that: The dehydration reaction is to dehydrate the hydrate of terpine diol and add it to a dehydration reaction kettle equipped with an oil-water separator, and add 2-3 times its mass of water and 0-0.5‰ of its mass of citric acid or tartaric acid, and the temperature is controlled at 100 °C-105 °C until no terpineol distills out.

10. The green production process for synthesizing 1,8-terpineol and dehydrating it to prepare perfume-grade terpineol according to claim 9, characterized in that: The dehydration product of the hydrate of terpine diol is put into a distillation kettle equipped with an oil-water separator, 2-3 times its mass of water is added, and 2-3% of its mass of β-molecular sieve is added, heated to boiling, the crude terpineol distilled out in the first 10 minutes is collected and purified by vacuum fractional distillation; continue distilling until no terpineol distills out, and the collected product is used as fragrance-grade terpineol; the hydrogen-type β-molecular sieve has a silica-alumina ratio of 25-30 and a particle size ≤ 5 μm.

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