Nickel/titanium oxide-silicon oxide catalyst for synthesizing terpinene-4-ol, preparation method thereof, and method of synthesizing terpinene-4-ol using the same

Abstract

The present invention discloses a nickel/titanium oxide-silicon oxide catalyst for synthesizing terpinene-4-ol as well as a preparation method and method of synthesizing terpinene-4-ol using the same. The preparation method includes the steps of catalyst preparation, terpinene-4-ol synthesis and the like are disclosed in the present invention. The preparation method includes the following steps: firstly, preparing a mixed colloid of TiO.sub.2 and SiO.sub.2 by using a sol-gel method, and then centrifuging, washing, drying and roasting is performed to prepare a TiO.sub.2—SiO.sub.2 binary oxide; then, preparing Ni/TiO2-SiO2 by dipping in a nickel nitrate solution, and preparing a supported catalyst by drying and roasting; and finally, adopting a terpinolene-4, 8-epoxide a raw material, carrying out isomerization under the dual catalytic action of TiO2-SiO2 and Ni of the supported catalyst, and carrying out hydrogenation to prepare terpinene-4-ol. The preparation method can combine isomerization and hydrogenation reaction on the same catalyst, has good selectivity on terpinene-4-ol, and is simple to operate and high in product yield.

Claims

1. A method for synthesizing terpinen-4-ol by using Ni/TiO.sub.2—SiO.sub.2 catalyst, comprising steps of: (1) adding terpinolene epoxide and Ni/TiO.sub.2—SiO.sub.2 catalyst into a reactor, performing an isomerization reaction at a preset first temperature, monitoring a progress of the isomerization reaction through sampling and analysis, and after confirming that the isomerization reaction is finished, cooling down temperature in the reactor to a preset second temperature and then passing hydrogen gas for a hydrogenation reaction; (2) performing a solid-liquid separation treatment when pressure of the reactor no longer reduces, an obtained liquid from the solid-liquid separation treatment is distilled under reduced pressure to obtain terpinen-4-ol.

2. The method for synthesizing terpinen-4-ol by using Ni/TiO.sub.2—SiO.sub.2 catalyst according to claim 1, the mass ratio of the terpinene epoxide to the Ni/TiO.sub.2—SiO.sub.2 catalyst is 1:0.03-1:0.1.

3. The method for synthesizing terpinen-4-ol by using Ni/TiO.sub.2—SiO.sub.2 catalyst according to claim 1, the preset first temperature for the isomerization reaction is 120-160° C.

4. The method for synthesizing terpinen-4-ol by using Ni/TiO.sub.2—SiO.sub.2 catalyst according to claim 1, wherein the second temperature for the hydrogenation reaction is 50-100° C., and pressure of the hydrogen gas is 0.5 MPa.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is the XRD pattern of TiO.sub.2, SiO.sub.2, TiO.sub.2—SiO.sub.2, Ni/TiO.sub.2—SiO.sub.2 catalyst;

(2) FIG. 2 is the SEM image of TiO.sub.2—SiO.sub.2 (a) and Ni/TiO.sub.2—SiO.sub.2 (b) catalysts;

(3) FIG. 3 shows the TEM images of SiO.sub.2 (a), TiO.sub.2—SiO.sub.2 (b), Ni/TiO.sub.2—SiO.sub.2 (c) and the element mapping of Ni (d), Si (e) and Ti (f).

DETAILED DESCRIPTION OF THE INVENTION

(4) To describe the technical contents, the structural features, the achieved objective and effect in detail, the following id described in detail with reference to the specific embodiments and the accompanying drawings.

Embodiment 1

(5) Step 1: Ethanol, water and ammonia solution is set and the pH of the solution is adjusted to about 11.6. 6 mL of tetraethyl silicate is slowly added dropwise to the mixed solution and the solution is heat to 40° C. and stirred for 3 h to prepare SiO.sub.2 emulsion. The SiO.sub.2 emulsion is centrifuged and washed, and then redispersed evenly into a mixed solution of ethanol, water and hydrochloric acid. The pH of the solution is adjusted to about 1.5 and 5 mL of tetrabutyl titanate is slowly added dropwise to the mixed solution of step 2, and the mixed solution is heat to 90° C. and stirred for 6 hours to obtain Ni/TiO.sub.2—SiO.sub.2 binary oxide emulsion. The binary oxide emulsion is centrifuged, washed, dried and roasted at 400° C. for 5 hours to obtain the isomerized catalyst Ni/TiO.sub.2—SiO.sub.2.

(6) Step 2: The solid TiO.sub.2—SiO.sub.2 is added to 0.5 mol/L nickel nitrate solution, stirred and immersed overnight at room temperature, dried, and roasted at 400° C. to obtain Ni/TiO.sub.2—SiO.sub.2.

(7) Step 3: The reduction of Ni/TiO.sub.2—SiO.sub.2 catalyst for 2 h under hydrogen flow at 500° C. is executed.

(8) Step 4: 40 g of terpinene 4,8 epoxide and 2 g of Ni/TiO.sub.2—SiO.sub.2 catalyst are added to the high-temperature and high-pressure reactor, stirred and mixed uniformly. the temperature is slowly raised to 120° C. for isomerization reaction, while using gas chromatography to check the progress of the reaction. After the isomerization is completed, the temperature is lowered to 60° C. and 1.5 MPa H.sub.2 is introduced to carry out hydrogenation reaction. After the reaction is completed, the solution is cooled to room temperature, separated by centrifugation, so as to recover and reuse the catalyst. The solution is subjected to vacuum distillation to obtain high-purity terpinen-4-ol.

(9) Detected by gas chromatography, the conversion rate of the isomerization reaction is 99%, the selectivity is 66%; the conversion rate of the hydrogenation reaction is 98%, and the selectivity is 99%. Overall, the terpinen-4-ol yield is over 60%.

Embodiment 2

(10) Step 1: Ethanol, water and ammonia solution is set and the pH of the solution is adjusted to about 11.4. 6 mL of tetraethyl silicate is slowly added dropwise to the mixed solution and the solution is heat to 30° C. and stirred for 2.5 h to prepare SiO.sub.2 emulsion. The SiO.sub.2 emulsion is centrifuged and washed, and then redispersed evenly into a mixed solution of ethanol, water and hydrochloric acid. The pH of the solution is adjusted to about 1.3 and 8 mL of tetrabutyl titanate is slowly added dropwise to the mixed solution of step 2, and the mixed solution is heat to 90° C. and stirred for 6 hours to obtain TiO.sub.2—SiO.sub.2 binary oxide emulsion. The binary oxide emulsion is centrifuged, washed, dried and roasted at 500° C. for 5 hours to obtain the isomerized catalyst TiO.sub.2—SiO.sub.2.

(11) Step 2: The solid TiO.sub.2—SiO.sub.2 is added to 0.75 mol/L nickel nitrate solution, stirred and immersed overnight at room temperature, dried, and roasted at 500° C. to obtain Ni/TiO.sub.2—SiO.sub.2.

(12) Step 3: The reduction of Ni/TiO.sub.2—SiO.sub.2 catalyst for 3 h under hydrogen flow at 500° C. is executed.

(13) Step 4: 40 g of terpinene 4,8 epoxide and 2.5 g of Ni/TiO.sub.2—SiO.sub.2 catalyst are added to the high-temperature and high-pressure reactor, stirred and mixed uniformly. the temperature is slowly raised to 130° C. for isomerization reaction, while using gas chromatography to check the progress of the reaction. After the isomerization is completed, the temperature is lowered to 70° C. and 1.5 MPa H.sub.2 is introduced to carry out hydrogenation reaction. After the reaction is completed, the solution is cooled to room temperature, separated by centrifugation, so as to recover and reuse the catalyst. The solution is subjected to vacuum distillation to obtain high-purity terpinen-4-ol.

(14) Detected by gas chromatography, the conversion rate of the isomerization reaction is 99%, the selectivity is 64%; the conversion rate of the hydrogenation reaction is 99%, and the selectivity is 99%. Overall, the terpinen-4-ol yield is over 60%.

Embodiment 3

(15) Step 1: Ethanol, water and ammonia solution is set and the pH of the solution is adjusted to about 11.3. 6 mL of tetraethyl silicate is slowly added dropwise to the mixed solution and the solution is heat to 40° C. and stirred for 3 h to prepare SiO.sub.2 emulsion. The SiO.sub.2 emulsion is centrifuged and washed, and then redispersed evenly into a mixed solution of ethanol, water and hydrochloric acid. The pH of the solution is adjusted to about 1.4 and 5 mL of tetrabutyl titanate is slowly added dropwise to the mixed solution of step 2, and the mixed solution is heat to 80° C. and stirred for 3 hours to obtain TiO.sub.2—SiO.sub.2 binary oxide emulsion. The binary oxide emulsion is centrifuged, washed, dried and roasted at 600° C. for 5 hours to obtain the isomerized catalyst TiO.sub.2—SiO.sub.2.

(16) Step 2: The solid TiO.sub.2—SiO.sub.2 is added to 1 mol/L nickel nitrate solution, stirred and immersed overnight at room temperature, dried, and roasted at 600° C. to obtain Ni/TiO.sub.2—SiO.sub.2.

(17) Step 3: The reduction of Ni/TiO.sub.2—SiO.sub.2 catalyst for 2 h under hydrogen flow at 500° C. is executed.

(18) Step 4: 40 g of terpinene 4,8 epoxide and 3 g of Ni/TiO.sub.2—SiO.sub.2 catalyst are added to the high-temperature and high-pressure reactor, stirred and mixed uniformly. the temperature is slowly raised to 140° C. for isomerization reaction, while using gas chromatography to check the progress of the reaction. After the isomerization is completed, the temperature is lowered to 80° C. and 2.0 MPa H.sub.2 is introduced to carry out hydrogenation reaction. After the reaction is completed, the solution is cooled to room temperature, separated by centrifugation, so as to recover and reuse the catalyst. The solution is subjected to vacuum distillation to obtain high-purity terpinen-4-ol.

(19) Detected by gas chromatography, the conversion rate of the isomerization reaction is 99%, the selectivity is 65%; the conversion rate of the hydrogenation reaction is 98%, and the selectivity is 99%. Overall, the terpinen-4-ol yield is over 60%.

(20) It should be noted that although the foregoing embodiments have been described herein, the scope of patent protection of the present invention is not limited thereby. Therefore, based on the innovative concept of the present invention, changes and modifications to the embodiments described herein, or equivalent structures or equivalent process transformations made by using the description and drawings of the present invention, directly or indirectly apply the above technical solutions. In other related technical fields, they are all included in the scope of patent protection of the present invention.