CN-115925512-A - Method for synthesizing tetrahydrolinalool

Abstract

The invention provides a method for preparing tetrahydrolinalool, which is characterized in that the tetrahydrolinalool is prepared in the presence of a catalyst, a diluent is not required to be added in the preparation process, the tetrahydrolinalool can be obtained by directly using the catalyst for pressure hydrogenation, the transfer rate and purity of a product can be improved by adding the catalyst, the pressure and temperature of hydrogenation are reduced, the operation is more convenient and safer, the catalyst is low in price, the catalyst can be recycled and reused by a simple treatment method, the activity of the catalyst is not obviously reduced after repeated use, the preparation cost is reduced, and three wastes are also greatly reduced.

Inventors

• XU YAN
• Wang Zhipin

Assignees

• SUQIAN KESI CHEM CO LTD

Dates

Publication Date

20230407

Application Date

20210831

Priority Date

20210831

Claims (10)

1. 1. A process for the preparation of tetrahydrolinalool, characterized in that it comprises the following steps: step 1, placing linalool and a catalyst in a reaction kettle, and then sealing the reaction kettle; step 2, introducing hydrogen into the reaction kettle, and then heating to carry out reaction; and 3, after the reaction is finished, carrying out post-treatment to obtain the tetrahydrolinalool.
2. 2. The method according to claim 1, wherein, in step 1, the catalyst is a supported catalyst, the carrier of the supported catalyst is one or more selected from carrier carbon, alumina, silica gel, diatomite and ZSM-5, the active component is one or more selected from Ru, pt, pb, pd, ni, rh and Ir.
3. 3. The method according to claim 2, wherein, in step 1, the mass ratio of linalool to catalyst is (50-250): 1, preferably the mass ratio is (55-220): 1, more preferably the mass ratio of (60 to 200): 1.
4. 4. the method according to claim 1, wherein, in step 2, hydrogen is introduced into the reactor to a pressure of 0.01 to 5.0MPa, preferably 0.3 to 0.8MPa, more preferably 0.4 to 0.5MPa.
5. 5. The method according to claim 1, wherein, in step 2, the temperature is raised to 60 to 110 ℃, preferably 70 to 100 ℃, and more preferably 80 to 100 ℃.
6. 6. The method according to claim 1, wherein, in step 2, the reaction is carried out under stirring, and the stirring speed is 500-1500 rpm.
7. 7. The method according to claim 1, wherein, in step 2, after the pressure in the reaction kettle is reduced, hydrogen is supplemented into the kettle, preferably, the pressure in the kettle is reduced by 0.05 to 0.1MPa, and the hydrogen is supplemented into the kettle to 0.2 to 1.0MPa.
8. 8. The method according to claim 1, wherein, in step 3, and (3) introducing cooling water into the coil pipe in the reaction kettle to reduce the temperature in the reaction kettle to 25-50 ℃.
9. 9. The method according to claim 1, wherein, in step 3, the post-treatment comprises filtration and rectification.
10. 10. Tetrahydrolinalool, characterized in that it is obtained by the process according to one of claims 1 to 9.

Description

Method for synthesizing tetrahydrolinalool Technical Field The invention relates to a fine chemical technology, in particular to a method for synthesizing tetrahydrolinalool. Background Tetrahydrolinalool, chemical name: 3, 7-dimethyl-3-octanol is colorless liquid, has more pleasant floral fragrance than linalool, is more stable to oxidation than linalool, is not easy to discolor, is not found in natural essential oil, can replace linalool to be used for preparing high-grade perfumed products, is particularly suitable for lily of the valley and rose fragrance, and has larger and larger future market demand. Therefore, how to improve the catalytic hydrogenation process of linalool and prepare high-purity tetrahydrolinalool is an urgent technical problem to be solved, and the chemical structural formula of the tetrahydrolinalool is shown as follows. At present, reports of hydrogenation reduction preparation of tetrahydrolinalool from linalool at home and abroad mainly include the following: in 2010, the process of obtaining tetrahydrolinalool by catalyzing the residual liquid of the vacuum distillation of linalool with 5 percent of Pd/C is reported by Wuzeg Yufei, but the hydrogenation pressure of the process is as high as 2.0MPa, the requirement on equipment is high, the dosage of the catalyst Pd/C is large, the price is high, and the reaction activity is remarkably reduced when the catalyst is repeatedly used for the 5 th time. ( Reference documents: the process for synthesizing tetrahydrolinalool from linalool vacuum distillation residual liquid [ J ] is a chemical process: 29,5 ) In 2013, zhangzhou reports that W-6 type Raney nickel is used as a catalyst and the process of obtaining tetrahydrolinalool through hydrogen high-pressure hydrogenation has high conversion rate and selectivity, but the process has the defects of high use amount of W-6 type Raney nickel, no commercial source, no water requirement on reaction, high requirement on linalool serving as a raw material and no report of a repeatedly used catalyst. ( Reference: zhangzhou, zhang qi et al research on high purity tetrahydrolinalool [ J ] spice essence cosmetics: 4,10 to 12 ) In 2020, the bauhinia reports a method for utilizing linalool rectifying still residual liquid by hydrogenation, wherein the related tetrahydrolinalool process has high hydrogenation pressure and reaction temperature and has strict requirements on equipment; diamine substances are added in the hydrogenation reaction to inhibit the generation of heavy component byproducts, so that the fragrance of the product is influenced; the required linalool raw material needs to be diluted, so that the method is not green and economical; there is no report of the catalyst being reused. ( Reference: a process for hydrogenating the residual liquid in linalool rectifying still (P), CN111205167,2020 ) The above reports about the hydrogenation reduction of linalool to prepare tetrahydrolinalool at home and abroad are that the requirements on raw material moisture are too high, or the requirements on pressure resistance and heat resistance of equipment are too high, the recycling frequency of the used catalyst is limited, the catalytic efficiency is reduced along with the increase of the recycling frequency, and the economy, environmental protection and safety of the process need to be further improved, so that how to obtain the high-yield, high-quality and environment-friendly tetrahydrolinalool preparation process is still worth exploring. Disclosure of Invention Based on the above technical background, the present inventors have made a keen search and, as a result, have found that: the preparation of linalool by introducing hydrogen under the addition of the catalyst can reduce the pressure and temperature in the preparation process of tetrahydrolinalool, the preparation process is mild, the requirements of pressure resistance and heat resistance of equipment are reduced, meanwhile, the adopted catalyst can be recycled and reused through simple filtration, and after repeated reuse, the activity of the catalyst is not obviously reduced, the preparation cost is effectively reduced, the preparation method is simpler and safer, and the yield and purity of the product are higher, thereby completing the invention. In a first aspect, the present invention provides a method for preparing tetrahydrolinalool, which comprises the following steps: step 1, placing linalool and a catalyst in a reaction kettle, and then sealing the reaction kettle; step 2, introducing hydrogen into the reaction kettle, and then heating to carry out reaction; and 3, after the reaction is finished, carrying out post-treatment to obtain the tetrahydrolinalool. In a second aspect, the present invention provides a tetrahydrolinalool prepared by the preparation method of the first aspect of the present invention. The preparation method of the tetrahydrolinalool and the tetrahydrolinalool prepared by the preparation method h