Preparation method of tetrahydrolinalool

Abstract

The invention discloses a preparation method of tetrahydrolinalool, belongs to the technical field of tetrahydrolinalool preparation, and overcomes the defects that in the prior art, in the tetrahydrolinalool preparation process, reaction liquid needs to be separated to meet subsequent use, and the process is complex. The preparation method of the tetrahydrolinalool comprises the following steps: S1, pre-activating a catalyst by using alkali liquor; the catalyst comprises a carrier and an active component, and the alkali liquor comprises an alkali metal element and / or an alkaline earth metal element; and S2, carrying out hydrogenation reduction on the dehydrolinalool in a fixed bed reactor to obtain a tetrahydrolinalool product by using the catalyst pre-activated in S1 and tetrahydrolinalool as a solvent. The dehydrolinalool can be efficiently hydrogenated into the tetrahydrolinalool, the product has few impurities and high yield, the reaction liquid can meet the use requirements without being separated, and the fragrance of the tetrahydrolinalool is better than that of the tetrahydrolinalool prepared by the traditional process.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of tetrahydro-linalool preparation, and particularly relates to a preparation method of tetrahydro-linalool. BACKGROUND

[0002] Tetrahydro-linalool is an organic compound that plays an important role in the fields of perfumery, medicine and organic synthesis. In the perfume industry, it is a key raw material for blending various artificial essential oils. With its sweet violet and lily of the valley fragrance, it is widely used in the preparation of berry flavors and other flavors, giving pleasant fragrance to perfume, cosmetics, detergents and other products, and improving product quality and appeal. In the medical field, tetrahydro-linalool can be used as a raw material for synthesizing drugs such as aprepitant, which can help prevent and control nausea and vomiting caused by chemotherapy, and bring good news to cancer patients. As an organic synthesis intermediate, it can participate in the synthesis of various complex organic molecules, and is indispensable in the research and production of new materials and fine chemicals, and has important significance for promoting the technological progress and product innovation of related industries.

[0003] Since tetrahydro-linalool products are mainly used in the flavor and fragrance market, the control of impurities is extremely high, because impurities often have a serious impact on the fragrance of the product. The existing technology for preparing tetrahydro-linalool usually uses a kettle reactor, which has a large backmixing, and the reaction liquid needs to be separated to meet the downstream use requirements. The existing process is difficult to separate and complex. SUMMARY

[0004] Therefore, the technical problem to be solved by the present application is to overcome the defects of the prior art that the reaction liquid needs to be separated to meet the subsequent use in the preparation process of tetrahydro-linalool, and to provide a preparation method of tetrahydro-linalool.

[0005] To this end, the present application provides the following technical solutions.

[0006] The present application provides a preparation method of tetrahydro-linalool, comprising the following steps:

[0007] S1, pre-activating a catalyst with a lye; the catalyst comprises a carrier and an active component, and the lye comprises an alkali metal element and / or an alkaline earth metal element;

[0008] S2, using the catalyst pre-activated in S1, hydrogenating dehydro-linalool to tetrahydro-linalool product in a fixed bed reactor with tetrahydro-linalool as a solvent.

[0009] In one possible implementation, S1 comprises: passing the lye into a fixed bed reactor filled with the catalyst to pre-activate the catalyst.

[0010] In one possible implementation, the pre-activation atmosphere is hydrogen.

[0011] In a possible implementation, the pre-activation reaction pressure is 0.5-5 MPa, preferably 1-3 MPa.

[0012] In a possible implementation, the pre-activation reaction temperature is 20-60℃, preferably 25-40℃.

[0013] In a possible implementation, the pre-activation feed mass hourly space velocity is 0.05-0.20 h -1 , preferably 0.08-0.15 h -1 .

[0014] In a possible implementation, the pre-activation time is 8-36 h, preferably 12-24 h.

[0015] In a possible implementation, the solvent of the lye is selected from one or more of amides, aliphatic alkanes, aromatic hydrocarbons, ethers, alcohols, preferably ethanol. The solvent of the lye is an inert solvent that does not react with tetrahydro-linalool and dehydro-linalool.

[0016] In a possible implementation, the solute of the lye is selected from one or more of strong bases or strong base weak acid salts, preferably potassium hydroxide; optionally, the lye is a potassium hydroxide ethanol solution.

[0017] In a possible implementation, the concentration of alkali metal elements or alkaline earth metal elements in the lye is 0.5wt%-4wt%, preferably 2wt%-4wt%.

[0018] In a possible implementation, the carrier includes one or more of alumina, calcium carbonate, diatomite.

[0019] In a possible implementation, the active component includes one or more of nickel, zinc, copper, palladium, platinum.

[0020] In a possible implementation, the loading of the active component in the catalyst is 3%-70%, preferably 40%-60%.

[0021] The loading of the active component refers to the mass percentage of metal elements in the active component in the catalyst.

[0022] In a possible implementation, in S2, the mass of tetrahydro-linalool in the feed is 5-30 times, preferably 10-20 times, the mass of dehydro-linalool.

[0023] In a possible implementation, S2 satisfies at least one of the following conditions:

[0024] (1) the reaction temperature for the hydrogenation reduction is 60-200 DEG C, preferably 90-150 DEG C;

[0025] (2) the reaction pressure for the hydrogenation reduction is 0.5-5 MPa, preferably 1-3 MPa;

[0026] (3) the mass space velocity is 0.05-0.20 h-1, preferably 0.08-0.15 h-1. -1 -1

[0027] The main reaction equation is as follows:

[0028]

[0029] The side reaction equation is as follows:

[0030]

[0031] In the present application, the fixed bed reactor is of metal material.

[0032] The technical scheme of the present application has the following advantages:

[0033] 1. The preparation method of tetrahydro-linalool comprises the following steps: S1, using an alkali liquor to pre-activate a catalyst; the catalyst comprises a carrier and an active component, and the alkali liquor comprises alkali metal elements and / or alkali earth metal elements; S2, using the catalyst pre-activated in S1, hydrogenating dehydro-linalool into tetrahydro-linalool product in a fixed bed reactor with tetrahydro-linalool as a solvent.

[0034] The present application uses a fixed bed reactor to prepare tetrahydro-linalool, which can avoid the back mixing problem of a tank reactor. However, the supported catalyst carrier used in the fixed bed reactor contains a large amount of oxygen vacancies. The oxygen vacancies attract electron pairs through their positive electric regions, showing acidity. When the fixed bed reactor is used to produce tetrahydro-linalool, hot spots appear in the catalyst bed, and tetrahydro-linalool will undergo a dehydration side reaction. The dehydration side reaction is prone to occur at high temperature and acidic sites to generate corresponding olefin impurities. This impurity will further hydrogenate to generate saturated alkanes under a hydrogen atmosphere, resulting in a decrease in yield. In addition, the reaction liquid needs to be separated and impurities removed to meet the use requirements. The present application uses an alkali liquor to pre-activate the catalyst. The alkali metal elements and alkali earth metal elements are more easily combined with oxygen vacancies under alkaline conditions to form stable complexes, thereby reducing the acidity of the oxygen vacancies. In addition, the alkali metal elements and alkali earth metal elements can reduce the activity of the acidic sites by changing the oxygen vacancy formation energy and changing the oxygen vacancy electron structure, thereby inhibiting the dehydration side reaction. The dehydro-linalool of the present application can be efficiently hydrogenated into tetrahydro-linalool with less impurities and high yield. The reaction liquid can meet the use requirements without separation, and the aroma of tetrahydro-linalool is better than that of the traditional process. DETAILED DESCRIPTION​​

[0035] The following examples are provided to better further understand the present application and are not limited to the best mode contemplated, do not constitute limitations on the scope of the application, and are not intended to convey any idea of the preferred or only embodiments contemplated. Any product obtained by the application of the present application as a combination with or without other prior art features, which is within the scope of the present application, is intended to be a product of this application. The present application is not limited to the embodiments described and shown in the drawings.

[0036] The experimental steps or conditions not specified in the examples can be carried out according to the conventional experimental steps described in the literature or the operation or conditions. The reagents or instruments not specified by the manufacturer are conventional reagent products that can be obtained by purchase.

[0037] The raw material sources in the examples are as follows:

[0038] Hydrogen (99.9%), Dalian Guangming Special Gases Co., Ltd.;

[0039] Potassium hydroxide, ethanol, barium hydroxide, N, N-dimethylformamide, China National Pharmaceutical Group;

[0040] Dehydrolinalool, tetrahydrolinalool, Wanhua Chemical;

[0041] Nickel-based catalyst (NOV141, carrier is alumina, active component is nickel, and the loading amount of the active component is 50%), palladium-based catalyst (carrier is alumina, active component is palladium, and the loading amount of the active component is 5%) are purchased from Jiangsu Xinnuo.

[0042] Example 1

[0043] The present embodiment provides a preparation method of tetrahydrolinalool, comprising the following steps:

[0044] 1) Preparation of alkali liquor: a certain amount of potassium hydroxide and ethanol were weighed and prepared into 3wt% potassium hydroxide ethanol solution (calculated by the mass content of alkali metal elements in the alkali liquor) for standby.

[0045] 2) The alkali liquor obtained in step 1) was passed into a fixed bed reactor filled with nickel-based catalyst NOV141 for pre-activation, hydrogen atmosphere, reaction pressure 2 MPa, reaction temperature 30℃, feed mass space velocity 0.12h -1 , pre-activation time 18h.

[0046] 3) Tetrahydrolinalool and raw material dehydrolinalool were prepared into a mixed solution, the mass of tetrahydrolinalool was 15 times the mass of dehydrolinalool, and the mixed solution was passed into the fixed bed reactor pre-activated in step 1) for hydrogenation reaction, feed mass space velocity 0.12h -1 , reaction temperature 120℃, reaction pressure 2 MPa.

[0047] 4) The reaction solution obtained in step 3) is tested for purity by gas chromatography. The mass content of tetrahydrolinalool is 99.64%, the mass content of dehydration by-product is 0.01%, and the mass content of other impurities is 0.35%.

[0048] Example 2

[0049] Tetrahydrolinalool is prepared according to the method of Example 1, except that the concentration of the prepared alkali solution in step 1) is 0.5 wt%.

[0050] Example 3

[0051] Tetrahydrolinalool is prepared according to the method of Example 1, except that the concentration of the prepared alkali solution in step 1) is 4 wt%.

[0052] Example 4

[0053] Tetrahydrolinalool is prepared according to the method of Example 1, except that the hydrogen pressure in step 2) is 1 MPa.

[0054] Example 5

[0055] Tetrahydrolinalool is prepared according to the method of Example 1, except that the hydrogen pressure in step 2) is 3 MPa.

[0056] Example 6

[0057] Tetrahydrolinalool is prepared according to the method of Example 1, except that the activation temperature in step 2) is 25°C.

[0058] Example 7

[0059] Tetrahydrolinalool is prepared according to the method of Example 1, except that the activation temperature in step 2) is 40°C.

[0060] Example 8

[0061] Tetrahydrolinalool is prepared according to the method of Example 1, except that the mass space velocity of the alkali solution in step 2) is 0.08 h -1 .

[0062] Example 9

[0063] Tetrahydrolinalool is prepared according to the method of Example 1, except that the mass space velocity of the alkali solution in step 2) is 0.15 h -1 .

[0064] Example 10

[0065] Tetrahydrolinalool is prepared according to the method of Example 1, except that the activation time in step 2) is 12 h.

[0066] Example 11

[0067] The method of Example 1 was used to prepare tetrahydro-linalool, except that the activation time in step 2) was 24 h.

[0068] Example 12

[0069] The method of Example 1 was used to prepare tetrahydro-linalool, except that the mass of tetrahydro-linalool in step 3) was 20 times the mass of dehydrolinalool.

[0070] Example 13

[0071] The method of Example 1 was used to prepare tetrahydro-linalool, except that the mass of tetrahydro-linalool in step 3) was 20 times the mass of dehydrolinalool.

[0072] Example 14

[0073] The method of Example 1 was used to prepare tetrahydro-linalool, except that the reaction temperature in step 3) was 90°C.

[0074] Example 15

[0075] The method of Example 1 was used to prepare tetrahydro-linalool, except that the reaction temperature in step 3) was 150°C.

[0076] Example 16

[0077] The method of Example 1 was used to prepare tetrahydro-linalool, except that the reaction pressure in step 3) was 1 MPa.

[0078] Example 17

[0079] The method of Example 1 was used to prepare tetrahydro-linalool, except that the reaction pressure in step 3) was 3 MPa.

[0080] Example 18

[0081] The present example provides a method for preparing tetrahydro-linalool, comprising the following steps:

[0082] 1) Preparation of alkali liquor: a certain amount of sodium hydroxide and N,N- dimethylformamide (DMF) were weighed and used to prepare a 3 wt% sodium hydroxide solution (based on the mass content of alkali metal elements in the alkali liquor) for use.

[0083] 2) The alkali liquor obtained in step 1) was passed into a fixed bed reactor packed with a palladium-based catalyst (alumina as carrier and palladium as active component, 5%) for pre-activation, hydrogen atmosphere, reaction pressure 2 MPa, reaction temperature 30°C, feed mass space velocity 0.12 h -1 , pre-activation time 18 h.

[0084] 3) The tetrahydro-linalool and the raw material dehydro-linalool were mixed to form a mixture, the mass of the tetrahydro-linalool was 15 times of the mass of the dehydro-linalool, the mixture was introduced into the fixed bed reactor pre-activated in step 1) to perform the hydrogenation reaction, the mass space velocity of the feed was 0.08h -1 , the reaction temperature was 120℃, and the reaction pressure was 2MPa.

[0085] 4) The reaction liquid obtained in step 3) was tested for purity by gas phase.

[0086] Example 19

[0087] The present embodiment provides a preparation method of tetrahydro-linalool, comprising the following steps:

[0088] 1) Preparation of alkali liquor: a certain amount of barium hydroxide and ethanol were weighed and mixed to prepare a 0.5wt% barium hydroxide ethanol solution (calculated as the mass content of alkaline earth metal elements in the alkali liquor) for standby.

[0089] 2) The alkali liquor obtained in step 1) was introduced into a fixed bed reactor filled with nickel-based catalyst NOV141 to perform pre-activation, the hydrogen atmosphere, the reaction pressure was 2MPa, the reaction temperature was 30℃, and the mass space velocity of the feed was 0.12h -1 , the pre-activation time was 18h.

[0090] 3) The tetrahydro-linalool and the raw material dehydro-linalool were mixed to form a mixture, the mass of the tetrahydro-linalool was 15 times of the mass of the dehydro-linalool, the mixture was introduced into the fixed bed reactor pre-activated in step 1) to perform the hydrogenation reaction, the mass space velocity of the feed was 0.15h -1 , the reaction temperature was 120℃, and the reaction pressure was 2MPa.

[0091] 4) The reaction liquid obtained in step 3) was tested for purity by gas phase.

[0092] Comparative Example 1

[0093] The tetrahydro-linalool was prepared according to the method of Example 1, except that no potassium hydroxide was added to the ethanol in step 1).

[0094] Comparative Example 2

[0095] The tetrahydro-linalool was prepared according to the method of Example 1, except that step 3) was directly performed to perform the hydrogenation reaction.

[0096] The tetrahydro-linalool products prepared in Examples 1-19 and Comparative Examples 1 and 2 were detected by GC, and the content of each component is shown in Table 1.

[0097] Table 1 Composition of tetrahydro-linalool product (mass percentage)

[0098]

[0099]

[0100] From Table 1, it can be seen that the purity of tetrahydrolinalool prepared by the method of the present application is more than 99%, which can meet the subsequent use requirements without separation and other steps, and can be directly sold.

[0101] The tetrahydrolinalool products prepared in Examples 1-19 and Comparative Examples 1 and 2 were submitted to 4 internal perfumers and 6 external perfumers for evaluation. The aroma intensity, aroma complexity, aroma characteristics, aroma persistence, and sensory evaluation were evaluated from five dimensions, and the specific evaluation criteria are as follows:

[0102] 1. Aroma intensity (full score 20 points)

[0103] Strong (18-20 points): The aroma is very strong and can quickly and strongly attract attention, even at a distance. It can be clearly perceived.

[0104] Moderate (12-17 points): The aroma intensity is moderate, neither too strong nor too weak, and can be continuously and stably perceived.

[0105] Weak (6-11 points): The aroma is relatively weak and needs to be close to be clearly perceived, or it may be difficult to detect in some cases.

[0106] 2. Aroma complexity (full score 20 points)

[0107] High complexity (18-20 points): The aroma is composed of many different aroma components, each of which can be clearly distinguished, and has good balance and coordination with each other.

[0108] Moderate complexity (12-17 points): The aroma is composed of several different aroma components, but not as clearly distinguished as high complexity, with a certain sense of hierarchy.

[0109] Simple (6-11 points): The aroma is mainly composed of single or a few aroma components, lacking complexity and hierarchy.

[0110] 3. Aroma characteristics (full score 20 points)

[0111] Unique and distinctive (18-20 points): The aroma has very unique characteristics, can be easily identified and distinguished from other aromas, and has a high degree of recognition.

[0112] General characteristics (12-17 points): The aroma has certain characteristics, but not as prominent as unique and distinctive aroma, can be identified but may lack some uniqueness.

[0113] Not obvious (6-11 points): The aroma characteristics are not obvious, difficult to distinguish from other aromas, and lack of recognition.

[0114] 4. Fragrance longevity (max. 20 points)

[0115] Long (18-20 points): The fragrance lasts very long in the air or in the human senses, even after a period of time it can still be perceived.

[0116] Medium (12-17 points): The fragrance lasts for a moderate period of time and can be perceived for a certain time, but not as long as long.

[0117] Short (6-11 points): The fragrance lasts for a short time and quickly dissipates, making it difficult to maintain for a long time.

[0118] 5. Sensory evaluation (max. 20 points)

[0119] Excellent (18-20 points): The fragrance gives a very pleasant feeling to the person and can cause a strong positive emotional response, being the best in the sensory experience.

[0120] Good (12-17 points): The fragrance gives a good feeling to the person and can cause a positive emotional response, but may not be as deep as excellent.

[0121] Average (6-11 points): The fragrance gives an average feeling to the person and may not cause a special emotional response, or there may be some negative feelings.

[0122] Using the above criteria, the evaluator can score each dimension according to the actual performance of the fragrance, and according to the score, it is classified into the corresponding grade. The total score is the sum of the scores of the five dimensions, with a maximum score of 100 points. The average score of the fragrance quality score is taken as the final score of the tetrahydro linalool product. The results are shown in Table 2.

[0123] Table 2 Fragrance evaluation of tetrahydro linalool product

[0124]

[0125]

[0126] As can be seen from Table 2, compared with Comparative Example 1 and Comparative Example 2, the products of Examples 1-19 have scores above 90 points, and in particular, the products of multiple examples such as Example 1 have scores higher than 95 points. This shows that the method of the present application can obtain tetrahydro linalool products with more transparent fragrance, better fragrance type and higher fragrance quality, which can be used in the field of higher-end daily-use fragrance perfumes such as perfumes.

[0127] Obviously, the above embodiments are only examples for clearly illustrating the present application and are not intended to limit the present application. Based on the above description, one of ordinary skill in the art can make other different forms of changes or modifications. Here, it is not necessary or possible to enumerate all the embodiments. The obvious changes or modifications derived from the above should be within the protection scope of the present application.

Claims

1. A method for preparing tetrahydro-linalool, characterized by, The method comprises the following steps: S1, pre-activating the catalyst using an alkali solution; the catalyst comprises a carrier and an active component, and the alkali solution comprises an alkali metal element and / or an alkaline earth metal element; S2, using the catalyst pre-activated in S1, hydrogenating dehydro-linalool into tetrahydro-linalool in a fixed bed reactor using tetrahydro-linalool as a solvent.

2. The method for preparing tetrahydro-linalool according to claim 1, characterized by, S1 comprises: introducing the alkali solution into a fixed bed reactor filled with the catalyst to pre-activate the catalyst.

3. The method of preparing tetrahydro-linalool according to claim 2, wherein At least one of the following conditions is met: (1) the pre-activation atmosphere is hydrogen; (2) the pre-activation reaction pressure is 0.5-5 MPa, preferably 1-3 MPa; (3) the pre-activation reaction temperature is 20-60℃, preferably 25-40℃; (4) the pre-activated feed mass space velocity is 0.05 to 0.20 h -1 , preferably 0.08 to 0.15 h -1 ; (5) the pre-activation time is 8-36 h, preferably 12-24 h.

4. The method of preparing tetrahydrolinalool according to any one of claims 1 to 3, characterized in that, The solvent of the alkali solution is selected from one or more of amides, aliphatic alkanes, aromatic hydrocarbons, ethers, and alcohols, preferably ethanol.

5. The method of preparing tetrahydrolinalool according to any one of claims 1 to 3, characterized in that, The solute of the alkali solution is selected from one or more of strong bases or strong base weak acid salts, preferably potassium hydroxide; optionally, the alkali solution is a potassium hydroxide ethanol solution.

6. The method of preparing tetrahydrolinalool according to any one of claims 1 to 3, characterized in that, In the alkali solution, the concentration of the alkali metal element or the alkaline earth metal element is 0.5wt%-4wt%, preferably 2wt%-4wt%.

7. The method for preparing tetrahydrolinalool according to any one of claims 1-3, characterized in that, The carrier comprises one or more of alumina, calcium carbonate, and diatomite.

8. The method for preparing tetrahydrolinalool according to any one of claims 1-3, characterized in that, The active component comprises one or more of nickel, zinc, copper, palladium, and platinum; And / or In the catalyst, the loading amount of the active component is 3%-70%.

9. The method of preparing tetrahydrolinalool according to any one of claims 1 to 3, characterized in that, In S2, the mass of tetrahydro-linalool in the feed is 5-30 times, preferably 10-20 times, the mass of dehydro-linalool.

10. The method of preparing tetrahydrolinalool according to any one of claims 1 to 3, characterized in that, S2 meets at least one of the following conditions: (1) the hydrogenation reaction temperature is 60-200℃, preferably 90-150℃; (2) the hydrogenation reaction pressure is 0.5-5 MPa, preferably 1-3 MPa; (3) mass space velocity 0.05 to 0.20 h -1 , preferably 0.08 to 0.15 h -1 .

Images