Reaction device for preparing terpineol from limonene and synthesis method thereof

Abstract

A reaction device for preparing terpineol from limonene and a synthesis method thereof are provided. The reaction device is provided with an evaporator, a reactor, a condenser, a catalyst basket, a steam riser and a siphon. The evaporator is provided with a raw material inlet and a discharge outlet. The upper portion of the evaporator is connected with the upper portion of the reactor through the steam riser. The condenser is arranged at the top of the reactor. The catalyst basket is arranged in the reactor. The siphon is connected with the reactor and the evaporator respectively. The evaporator is heated. The raw material, water and solvent are evaporated through the steam riser and condensed in the condenser. The condensed liquid is reacted with the catalyst. When the liquid level in the reactor is higher than the height of the siphon, the liquid in the reactor is returned to the evaporator by the pressure difference. The raw material, water and solvent in the evaporator are continuously evaporated and reacted. The process is repeated. After the reaction is completed, the heating is stopped, the discharge outlet is opened, the discharged material is separated by rectification, and terpineol is obtained. The reaction synthesis of terpineol from limonene is easy for subsequent rectification and separation, the reaction time is short, and the process is simple.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of essence and flavor synthesis, in particular to a reaction device for preparing terpineol from limonene and a synthesis method thereof. BACKGROUND

[0002] Terpineol (molecular formula C 10 H 18 O) is a colorless transparent viscous liquid with lilac odor. Due to its unique fragrance and good sterilization and disinfection capacity, it is widely used as a fine chemical product such as a flavoring agent, a sterilizing agent, a disinfectant, an immune enhancing drug, a sedative, a detergent, a high-grade solvent, a printing agent, and a flotation agent. It can also be used to synthesize high value-added downstream products such as 1,8-eucalyptol, camphor, borneol, and linalool. The disinfectant prepared from terpineol has a high killing rate on bacteria such as Escherichia coli, Staphylococcus aureus, Candida albicans, and Pseudomonas aeruginosa, and has no skin irritation and good stability.

[0003] At present, terpineol has been found in the leaves, flowers, and stems of more than 200 plants. However, the economic value of extracting terpineol from plants is very low, and the content and yield are quite limited, which cannot meet the industrial demand. Therefore, terpineol is mainly produced by chemical synthesis method using turpentine oil as raw material in industry. Terpineol has the largest yield in the series of deep processing products of turpentine oil, which exceeds 50,000 tons / year. China has the largest production of turpentine oil in the world, which provides sufficient raw material sources for the production of terpineol.

[0004] The chemical synthesis method of terpineol mainly uses turpentine oil as raw material to synthesize terpineol by one-step or two-step method. The one-step method is to directly synthesize terpineol by hydration reaction of raw material turpentine oil under the catalysis of protonic acid. The one-step synthesis reaction has simple process, less process, short production cycle, and mainly uses solid acid catalyst, which does not cause corrosion of equipment and pollution of environment. However, the main hydration product of one-step synthesis reaction is α-terpineol (yield about 35.4%), and the product contains less γ-terpineol and no β-terpineol, which has poor fragrance. The two-step method is to first hydrate the raw material turpentine oil to generate hydrated terpene diol crystal under the catalysis of concentrated sulfuric acid and other protonic acids, and then to generate terpineol by dehydration under the catalysis of dilute sulfuric acid. The two-step synthesis reaction has complex process, more process, long production cycle, and uses sulfuric acid as catalyst, which causes serious corrosion of equipment and environmental pollution. However, the hydration reaction product of two-step method contains a certain amount of γ-terpineol and β-terpineol in addition to the main product α-terpineol, which has better fragrance.

[0005] Overall, a series of isomerization, hydration and dehydration side reactions are accompanied in the reaction process of synthesizing terpineol from turpentine oil as raw material, and there are many by-products, mainly including camphene, 2-carene, limonene, isoterpinene, 1,4-eudesmol, 1,8-eudesmol, borneol, isoborneol, hydrated terpene glycol, fenchol, etc., therefore, it is more difficult to obtain high-purity terpineol product by fractional distillation and purification of the reaction product. SUMMARY

[0006] The present application aims to solve the above problems in the prior art, and provides a reaction device for preparing terpineol from limonene and a synthesis method thereof, which is simple in process and friendly to the environment.

[0007] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0008] A reaction device for preparing terpineol from limonene, which is provided with an evaporator, a reactor, a condenser, a catalyst basket, a steam riser and a siphon tube; the evaporator is provided with a raw material inlet and a discharge outlet, and the upper part of the evaporator is connected with the upper part of the reactor through the steam riser; the condenser is arranged at the top of the reactor; the catalyst basket is arranged in the reactor; one end of the siphon tube is connected with the reactor, and the other end of the siphon tube is connected with the evaporator.

[0009] A method for synthesizing terpineol by using the reaction device for preparing terpineol from limonene, which comprises the following steps:

[0010] 1) The catalyst and Θ ring stainless steel wire mesh packing are mixed and filled into the catalyst basket, which is placed in the reactor and closed;

[0011] 2) The discharge outlet of the evaporator is closed, the raw material, water and solvent are mixed and then added into the evaporator, and the raw material inlet is closed; the raw material contains limonene, and the solvent is alcohol or liquid carbon dioxide;

[0012] 3) The evaporator is heated, the raw material, water and solvent are evaporated through the steam riser and condensed in the condenser, and the condensed liquid contacts the catalyst for catalytic reaction; after a period of reaction, the liquid level in the reactor is higher than the height of the siphon tube, so that the liquid in the reactor returns to the evaporator by pressure difference; the raw material, water and solvent in the evaporator are continuously evaporated and reacted, and the process is repeated; after the reaction is completed, the heating is stopped, the discharge outlet is opened, and the discharged material is separated by fractional distillation to obtain terpineol product, and the unreacted raw material and solvent are returned to the evaporator for repeated use.

[0013] The alcohol is selected from one of methanol, ethanol, propanol, isopropanol and butanol, and isopropanol is preferred.

[0014] The content of limonene in the raw material is 70% to 100%.

[0015] The mass ratio of the raw material, water and solvent is 5: (0.6-2.5): (2.4-9.5); the mass ratio of the raw material and catalyst is 1:0.4-1:0.9.

[0016] The temperature of the evaporator is 150-200 DEG C; the reactor controls the temperature of the reaction to be 75-80 DEG C.

[0017] The porosity of the catalyst basket is 20%-50%.

[0018] The catalyst is a solid sulfonic acid type cation exchange resin, which is used after being washed by water or alcohol and dried.

[0019] The catalyst is selected from HND-8, HND-582, HND-583 and HND-587.

[0020] In the application, the reaction time is 6-24 hours.

[0021] Compared with the prior art, the application has the following beneficial effects:

[0022] 1. The conversion rate of limonene in the raw material reaches 94.3% at most, the yield of the main product alpha-terpineol reaches 50.1% at most, the total alcohol yield of terpineol (including 1-terpineol, 4-terpineol, beta-terpineol, alpha-terpineol, gamma-terpineol and delta-terpineol) reaches 67.8% at most, and the fragrance type is better as a perfume. Meanwhile, the isomerization reaction product is a byproduct with high added value, such as isoterpinen-4-ol and gamma-terpinene. In general, the reaction product of the reaction for synthesizing terpineol from limonene has fewer components than the reaction for synthesizing terpineol from turpentine oil, is easy to separate by subsequent rectification, has a short reaction time, a simple reaction process, is easy to operate, and has a short production cycle.

[0023] 2. The solid acid catalyst effectively solves the problems of equipment corrosion and environmental pollution, does not produce acidic wastewater, and can be recycled and directly reused.

[0024] 3. The solvent is low-carbon alcohol such as methanol, ethanol and propanol, which has low cost and is easy to separate by subsequent rectification, recover and reuse;

[0025] 4. The limonene raw material is widely available and sufficient, and natural plant essential oil containing limonene such as citrus essential oil can be directly used as the raw material, so that the cost of synthesizing terpineol is effectively reduced. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 It is a structural schematic view of the reaction device of the application;

[0027] Figure 2 It is a spectrum diagram of gas chromatography-mass spectrometry (GC-MS) of the reaction product of Example 1. DETAILED DESCRIPTION

[0028] In order to make the technical problems, technical solutions and beneficial effects of the present application more clear and explicit, the present application is further described in detail below in combination with the drawings and examples.

[0029] As shown in Figure 1 The reaction device for preparing terpineol from limonene of the present application is provided with an evaporator A, a steam riser B, a catalyst basket C, a reactor D, a siphon E and a condenser F.

[0030] The upper part of the evaporator A is connected with the upper part of the reactor D through the steam riser B, the condenser F is arranged at the top of the reactor D, and the catalyst basket C is arranged in the reactor D; a heating jacket and a thermal insulation layer are arranged outside the evaporator A and the reactor D; the two ends of the condenser F are the cooling water inlet and the cooling water outlet; one end of the siphon E is connected with the reactor D, and the other end of the siphon E is connected with the evaporator A; the height of the top of the siphon is lower than the height of the top of the reactor.

[0031] The evaporator A is provided with a raw material inlet and a discharge outlet, the raw material inlet is provided with a feeding valve V1, and the discharge outlet is provided with a discharge valve V2.

[0032] The temperature sensing and control system includes the heating, temperature display and temperature control T1 of the material in the evaporator A, the heating, temperature display and temperature control T2 of the material in the reactor D and the cooling, temperature display and temperature control T3 of the condenser F.

[0033] The pressure sensing and control system includes the display and control P1 of the pressure in the evaporator A and the display and control P2 of the pressure in the reactor D.

[0034] The method for synthesizing terpineol from limonene of the present application is as follows:

[0035] Firstly, the catalyst and Θ ring stainless steel wire mesh packing are mixed and filled into the catalyst basket C, fixed at the lower part of the condenser F, placed in the reactor D and closed; secondly, the discharge valve V2 is closed, the raw material and solvent are mixed and then added into the evaporator A, and the feed valve V1 is closed; the evaporator A is heated, the raw material, water and solvent are evaporated and condensed in the condenser F, and the condensed liquid contacts the catalyst for catalytic reaction; after a period of reaction, the liquid level in the reactor D is higher than the height of the siphon E, and the reaction product and unreacted raw material, water and solvent are returned to the evaporator A by pressure difference; in the reaction system, water and solvent and water and limonene are continuously evaporated azeotropically, and the boiling point of terpineol is much higher than the above two azeotropes, so the terpineol produced is left in the evaporator A, which avoids the contact reaction of terpineol and catalyst to the greatest extent; the raw material is continuously evaporated into the reactor D for reaction, and when the content of limonene in the evaporator A is less than 10% through sampling analysis, the heating is stopped, the discharge valve V2 is opened, and the material is discharged for rectification separation to obtain terpineol product. The unreacted raw material and solvent are returned to the evaporator A again for repeated use.

[0036] The purpose of the heating jacket and the heat preservation layer outside the reactor is to ensure that the temperature in the reactor is maintained in the optimal reaction temperature range; the condenser is placed on the top of the catalyst basket, and by adjusting the flow and temperature of the condensing water in the condenser, the condensation rate can be controlled; the reaction time is 6-24h, and the reaction is completed within 12h, and the mass concentration of limonene in the evaporator can be less than 10%.

[0037] The catalyst type is a solid sulfonic acid type cation exchange resin, including HND-8, HND-582, HND-583, HND-587 and the like, and the catalyst is dried for use after being washed with water or alcohol.

[0038] The principle of the present application is as follows:

[0039] Since the boiling point of terpineol is high and it does not form an azeotrope with other components, the terpineol in the evaporator A is gradually enriched and concentrated, while water, solvent and limonene are evaporated azeotropically at a certain ratio and condensed in the condenser F, and then enter the reactor D for reaction. When the liquid level accumulates to the level of the siphon, according to the siphon principle, the reaction liquid returns to the evaporator A, and then water, solvent and limonene continue to evaporate azeotropically at a certain ratio and circulate continuously; due to the special effect of reaction distillation, the product on the surface of the catalyst is easily washed by the raw material condensate and quickly separated from the catalyst, without staying on the catalyst to cause back mixing, which further avoids the occurrence of side reactions, and the yield of the product terpineol is significantly improved.

[0040] Example 1

[0041] The mass ratio of raw material (containing limonene 97.3%), water and isopropanol is 5:1.5:6, the temperature of evaporator is set at 175°C, the temperature of reactor is controlled at 78-80°C, the amount of catalyst is 0.6 times of the amount of raw material, and the reaction time is 12 hours. After the reaction, the product is subjected to simple distillation to remove the solvent, and gas chromatography analysis shows that the conversion rate of limonene is 94.3%, the yield of α-terpineol is 50.1%, and the total alcohol yield is 67.8%. The GC-MS spectrum of the reaction product is shown in Figure 1. Figure 2 .

[0042] Table 1 is the composition of the reaction product according to the GC-MS spectrum of the reaction product.

[0043] The reaction product mainly contains α-terpineol, γ-terpineol, β-terpineol, etc., and also contains a small amount of isomeric by-products isopinocamphone, γ-pinocamphone and hydrated by-product 1,8-terpinediol, and the terpineol product can be obtained by distillation operation.

[0044] Table 1

[0045]

[0046] Example 2

[0047] The mass ratio of raw material (containing limonene 85.0%), water and isopropanol is 5:2:3, the temperature of evaporator is set at 185°C, the temperature of reactor is controlled at 75-78°C, the amount of catalyst is 0.5 times of the amount of raw material, and the reaction time is 14 hours. After the reaction, the product is subjected to simple distillation to remove the solvent, and gas chromatography analysis shows that the conversion rate of limonene is 92.0%, the yield of α-terpineol is 48.1%, and the total alcohol yield is 59.2%.

[0048] Example 3

[0049] The mass ratio of raw material (containing limonene 90.2%), water and ethanol is 5:1.5:6, the temperature of evaporator is set at 165°C, the temperature of reactor is controlled at 75-78°C, the amount of catalyst is 0.6 times of the amount of raw material, and the reaction time is 12 hours. After the reaction, the product is subjected to simple distillation to remove the solvent, and gas chromatography analysis shows that the conversion rate of limonene is 92.3%, the yield of α-terpineol is 48.9%, and the total alcohol yield is 62.8%.

[0050] Example 4

[0051] The mass ratio of the raw material (containing limonene 85.3%), water and isopropanol is 5:0.6:6, the evaporator temperature is set to 165℃, the temperature of the reactor is controlled at 78-80℃, the catalyst amount is 0.8 times of the raw material amount, and the reaction time is 20h. After the reaction, the product is subjected to simple distillation to remove the solvent, and gas chromatography analysis is performed, and the conversion rate of limonene is calculated to be 93.5%, the yield of α-terpineol is 47.4%, and the total alcohol yield is 63.2%.

[0052] Example 5

[0053] The mass ratio of the raw material (containing limonene 85.3%), water and isopropanol is 5:0.6:6, the evaporator temperature is set to 165℃, the temperature of the reactor is controlled at 78-80℃, the catalyst amount is 0.8 times of the raw material amount, and the reaction time is 20h. After the reaction, the product is subjected to simple distillation to remove the solvent, and gas chromatography analysis is performed, and the conversion rate of limonene is calculated to be 93.5%, the yield of α-terpineol is 47.4%, and the total alcohol yield is 63.2%.

[0054] Example 6

[0055] The mass ratio of the raw material (containing limonene 85.3%), water and isopropanol is 5:0.6:6, the evaporator temperature is set to 165℃, the temperature of the reactor is controlled at 78-80℃, the catalyst amount is 0.8 times of the raw material amount, and the reaction time is 20h. After the reaction, the product is subjected to simple distillation to remove the solvent, and gas chromatography analysis is performed, and the conversion rate of limonene is calculated to be 93.5%, the yield of α-terpineol is 47.4%, and the total alcohol yield is 63.2%.

[0056] The conversion rate of limonene in the raw material of the application is up to 94.3%, the yield of the main product α-terpineol is up to 50.1%, and the total alcohol yield is up to 67.8%, which is better as a fragrance. At the same time, the isomerization reaction product is a by-product with high added value: isopinocampheene, γ-pinenene, etc. In summary, the reaction product of limonene as a raw material for synthesizing terpineol is significantly less than the reaction of pine oil for synthesizing terpineol, which is easy to separate by subsequent distillation, and the reaction time is short, the reaction process is simple, and the production cycle is short.

Claims

1. A method of synthesizing terpineol, characterized by: The application discloses a reaction device for preparing terpineol from limonene, which comprises an evaporator, a reactor, a condenser, a catalyst basket, a steam riser and a siphon. The method for synthesizing terpineol comprises the following steps: 1) mixing and loading a catalyst and a Θ ring stainless steel wire mesh packing into the catalyst basket, placing the catalyst basket in the reactor and sealing the reactor; 2) closing the discharge port of the evaporator, mixing raw materials, water and a solvent, and then adding the mixture into the evaporator, and closing the raw material inlet; the raw materials contain limonene, and the solvent is alcohol or liquid carbon dioxide; 3) heating the evaporator, and evaporating the raw materials, water and the solvent through the steam riser and condensing the raw materials, water and the solvent in the condenser; the condensed liquid contacts the catalyst to perform a catalytic reaction; after a period of reaction, the liquid level in the reactor is higher than the height of the siphon, so that the liquid in the reactor returns to the evaporator by means of pressure difference; the raw materials, water and the solvent in the evaporator are continuously evaporated and reacted, and the process is repeated; after the reaction is completed, the heating is stopped, the discharge port is opened, and the discharged materials are separated by rectification to obtain terpineol products; the unreacted raw materials and the solvent are returned to the evaporator again for repeated use; the catalyst is selected from HND-8, HND-582, HND-583 and HND-587, and the catalyst is dried after being washed with water or alcohol.

2. The method of synthesizing terpineol according to claim 1, wherein: The alcohol is selected from one of methanol, ethanol, propanol, isopropanol and butanol.

3. The method of synthesizing terpineol according to claim 2, wherein: The alcohol is isopropanol.

4. The method of synthesizing terpineol according to claim 1, wherein: The content of limonene in the raw materials is 70% to 100%.

5. The method of synthesizing terpineol of claim 1, characterized by: The mass ratio of the raw materials, water and the solvent is 5:(0.6 to 2.5):(2.4 to 9.5). The mass ratio of the raw materials and the catalyst is 1:0.4 to 1:0.

9.

6. The method of synthesizing terpineol of claim 1, characterized in that: The temperature of the evaporator is 150 to 200 DEG C; and the temperature of the reactor for controlling the reaction is 75 to 80 DEG C.

7. The method of synthesizing terpineol of claim 1, characterized by: The porosity of the catalyst basket is 20% to 50%.

8. The method of synthesizing terpineol of claim 1, characterized by: The reaction time is 6 to 24 hours.

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