Preparation method of Cu / SiO2 catalyst and application of Cu / SiO2 catalyst in catalytic hydrogenation for preparing sandalwood 196

Abstract

The application belongs to the technical field of organic synthesis, and discloses a preparation method of a Cu / SiO2 catalyst and application of the Cu / SiO2 catalyst in catalytic hydrogenation for preparing sandalwood 196, wherein the catalyst is prepared by the following steps: adding silicate and organic amine into an ethanol solution, stirring until uniform, adjusting pH to alkaline, continuously stirring to obtain a silica solution, washing the silica solution with deionized water until neutral, then dispersing the silica solution in an ethanol solution, adding an ammonia solution of a copper salt into the silica ethanol solution after stirring and heating, continuously stirring and aging, washing the catalyst with deionized water until neutral after aging, and vacuum drying to obtain the Cu / SiO2 catalyst. The catalyst prepared by the application can realize one-step hydrogenation and simultaneously reduce carbon-carbon double bonds and carbon-oxygen double bonds to prepare sandalwood 196. The catalyst prepared has high catalytic activity, good conversion rate and selectivity of the target product, can be recycled and used, has mild reaction conditions, is easy to operate, has low preparation cost, is pollution-free, and is conducive to realizing industrialized production of sandalwood 196.

Description

Technical Field

[0001] The present invention belongs to the technical field of organic synthesis and relates to the preparation of sandalwood 196, and particularly to a preparation method of a Cu / SiO2 catalyst and application thereof in the preparation of sandalwood 196 by catalytic hydrogenation. Background Art

[0002] Sandalwood 196, also known as 2-borneolenyl propanol, has a strong sandalwood aroma with musky undertones. It is a liquid with a boiling point of 262.5±9.0°C. It is an important fragrance in the fine chemical industry and is widely used in cosmetic fragrances, soap fragrances, detergent fragrances, household fragrances, and high-end cosmetics.

[0003]

[0004] At present, the synthesis processes of sandalwood 196 mainly include:

[0005] (1) CN 101891594 B prepares 2-borneolenyl propanol through a three-step reaction of aldol condensation, hydrogenation reduction, and chemical reduction. The first step is the aldol condensation of borneolenal and propionaldehyde. The second step is the hydrogenation of 2-borneolenyl propanal, isopropyl alcohol, copper chromite, etc., and the third step is the reduction of 2-borneolenyl propanal with sodium borohydride. Finally, sandalwood 196 is obtained after purification. This report uses chlorinated solvents and N,N-dimethylformamide, which pollute the environment and are not environmentally friendly. In addition, the reduction reaction is a two-step process using sodium borohydride, a highly explosive substance, which not only reduces production efficiency but also poses a safety hazard.

[0006] (2) Another traditional method is to hydrogenate 2-borneolenylpropanal with Pd / C catalysis to obtain 2-borneolenylpropanal intermediate, and then reduce the aldehyde group with sodium borohydride to obtain sandalwood 196. This method also uses a two-step reduction method and also uses sodium borohydride. It also has problems such as low production efficiency and great safety hazards. Summary of the Invention

[0007] In view of the shortcomings of the prior art, the present invention aims to provide a method for preparing a Cu / SiO2 catalyst. In the present invention, an active copper species is loaded on a SiO2 carrier and applied to the one-step hydrogenation of 2-borneolenylpropionaldehyde to prepare sandalwood 196. The catalytic activity prepared by the present invention is high, the conversion rate and selectivity of the target product are good, the reaction conditions are mild, the operation is easy, and the catalyst can be recycled to realize the industrial production of sandalwood 196.

[0008] The present invention is achieved through the following technical solutions:

[0009] A method for preparing a Cu / SiO2 catalyst comprises the following steps:

[0010] Silicate ester and organic amine are added to an ethanol solution, stirred evenly, the pH is adjusted to alkaline, and stirring is continued to obtain a silica solution. The silica solution is washed with deionized water until neutral, and then dispersed in an ethanol solution. After stirring and heating, an ammonia solution of copper salt is added to the silica ethanol solution, and stirring is continued for aging. After aging, the solution is washed with deionized water until neutral, and vacuum dried to obtain a Cu / SiO2 catalyst.

[0011] A further improvement of the present invention is:

[0012] The silicate is one of methyl orthosilicate, ethyl orthosilicate, propyl orthosilicate or isopropyl silicate, or a mixture of two or more thereof.

[0013] Furthermore, the organic amine is one or a mixture of two or more of morpholine, tetrahydropyrrole, ethylenediamine or triethylamine.

[0014] Furthermore, the copper salt is one or a mixture of two or more of copper chloride, copper sulfate or copper nitrate.

[0015] Furthermore, the mass ratio of the silicate, the organic amine and the ammonia water is (1-10):1:(1:20).

[0016] Furthermore, the mass ratio of copper to silica support in the prepared Cu / SiO2 catalyst is 1:(10-100).

[0017] Further, stirring and heating to 40-60° C., adding copper salt ammonia solution, aging temperature is 40-60° C., aging time is 3-5 h; vacuum drying temperature is 90-110° C., time is 10-14 h.

[0018] A further improvement of the present invention is:

[0019] The use of the Cu / SiO2 catalyst prepared by the above method in catalytic hydrogenation to prepare sandalwood 196 comprises the following steps: dissolving 2-borneolenylpropanal in an organic solvent, adding the Cu / SiO2 catalyst to the system, heating the system to 100-150°C, replacing the atmosphere with nitrogen, pressurizing the hydrogen to 10-30 bar, and conducting a hydrogenation reaction to obtain sandalwood 196.

[0020] Furthermore, the organic solvent is one or a mixture of two or more of methanol, ethanol or toluene.

[0021] Furthermore, the mass ratio of the 2-borneolenyl propionaldehyde, the organic solvent and the Cu / SiO2 catalyst is 1:(0.1-3):(0.001-0.01).

[0022] The beneficial effects of the present invention are:

[0023] The catalyst prepared by the present invention achieves the purpose of preparing sandalwood 196 by simultaneously reducing carbon-carbon double bonds and carbon-oxygen double bonds through one-step hydrogenation. The catalyst has the advantages of high catalytic activity, good target product conversion rate and selectivity, and recyclability. The use of the catalyst prepared by the present invention to prepare sandalwood 196 has mild reaction conditions, easy operation, and the catalyst is easy to use, low cost, and pollution-free, which is conducive to the industrial production of sandalwood 196. DETAILED DESCRIPTION

[0024] The present invention is described in detail below with reference to specific embodiments. Example 1

[0025] Catalyst preparation: Add 10g of methyl orthosilicate and 2g of ethylenediamine to 50mL of ethanol solution and stir evenly. Then add 10g of 10% ammonia solution to adjust the pH to alkaline and continue stirring at room temperature for 4-6h to obtain a silica solution. Wash the silica solution with deionized water until neutral, then disperse it in 50mL of ethanol solution and heat it to 50℃ while stirring. Then add 0.2g of copper chloride solution dissolved in 10g of ammonia water to the silica ethanol solution and continue stirring and aging at 50℃ for 4h. Then wash the obtained Cu / SiO2 with deionized water until neutral and dry it at 100℃ under vacuum for 12h to obtain a highly active Cu / SiO2 catalyst.

[0026] Synthesis of Sandalwood 196: 100 g of 2-borneolenylpropanal and 50 g of methanol were added to a hydrogenation reactor. 0.5 g of Cu / SiO2 catalyst was then added to the reaction system. After the addition of the ingredients, the hydrogenation reactor was sealed and replaced with nitrogen and hydrogen three times. The temperature was then raised to 130°C and 10 bar of hydrogen was introduced. The reaction was kept at this temperature for 2-4 hours until the residual raw material content was less than 0.5%. The reaction was terminated and the catalyst was filtered out and reused. The filtrate was subjected to vacuum distillation to obtain 100 g of finished Sandalwood 196 in a yield of 98%. Example 2

[0027] Catalyst preparation: Add 10g of ethyl orthosilicate and 2g of tetrahydropyrrole to 50mL of ethanol solution and stir evenly. Then add 10g of 10% ammonia solution to adjust the pH to alkaline and continue stirring at room temperature for 4-6h to obtain a silica solution. Wash the silica solution with deionized water until neutral, then disperse it in 50mL of ethanol solution and heat it to 60℃ while stirring. Then add 0.2g of copper chloride solution dissolved in 10g of ammonia water to the silica ethanol solution and continue stirring and aging at 60℃ for 4h. Then wash the obtained Cu / SiO2 with deionized water until neutral and dry it at 100℃ under vacuum for 12h to obtain a highly active Cu / SiO2 catalyst.

[0028] Sandalwood 196 synthesis: 100 g of 2-Adamantylidenepropionaldehyde and 50 g of methanol were added to a hydrogenation autoclave, and then 1 g of Cu / SiO2 catalyst was added to the reaction system. After the completion of feeding, the hydrogenation autoclave was closed, and the autoclave was replaced with nitrogen and hydrogen three times, respectively. Then the temperature was raised to 150 degrees, 20 bar of hydrogen was introduced, and the reaction was carried out at constant temperature for 2-4 h until the residual raw material was less than 0.5%. The reaction was completed, the catalyst was filtered out, and the catalyst could be reused. The filtrate was subjected to vacuum rectification to obtain 99 g of sandalwood 196 product, with a yield of 97%. Example 3

[0029] Catalyst preparation: 10 g of tetraethyl orthosilicate and 2 g of morpholine were added to a 50 mL ethanol solution, stirred uniformly, and then 10 g of 10% ammonia water solution was added to adjust the pH to alkaline. Continue to stir at room temperature for 4-6 h to obtain a silica solution. The silica solution was washed with deionized water until neutral, then dispersed in 50 mL of ethanol solution, and heated to 50°C under stirring. Then 0.2 g of copper sulfate solution dissolved in 10 g of ammonia water was added to the silica ethanol solution, and continued to stir and age at 50°C for 4 h. Then the obtained Cu / SiO2 was washed with deionized water until neutral, and dried at 100°C under vacuum conditions for 12 h to obtain a high-activity Cu / SiO2 catalyst.

[0030] Sandalwood 196 synthesis: 100 g of 2-Adamantylidenepropionaldehyde and 50 g of methanol were added to a hydrogenation autoclave, and then 1 g of Cu / SiO2 catalyst was added to the reaction system. After the completion of feeding, the hydrogenation autoclave was closed, and the autoclave was replaced with nitrogen and hydrogen three times, respectively. Then the temperature was raised to 150 degrees, 20 bar of hydrogen was introduced, and the reaction was carried out at constant temperature for 2-4 h until the residual raw material was less than 0.5%. The reaction was completed, the catalyst was filtered out, and the catalyst could be reused. The filtrate was subjected to vacuum rectification to obtain 99 g of sandalwood 196 product, with a yield of 97%. Example 4

[0031] Catalyst reuse 1:

[0032] Sandalwood 196 synthesis: 100 g of 2-Adamantylidenepropionaldehyde and 50 g of methanol were added to a hydrogenation autoclave, and then 1 g of Cu / SiO2 catalyst was added to the reaction system. After the completion of feeding, the hydrogenation autoclave was closed, and the autoclave was replaced with nitrogen and hydrogen three times, respectively. Then the temperature was raised to 150 degrees, 20 bar of hydrogen was introduced, and the reaction was carried out at constant temperature for 2-4 h until the residual raw material was less than 0.5%. The reaction was completed, the catalyst was filtered out, and the catalyst could be reused. The filtrate was subjected to vacuum rectification to obtain 99 g of sandalwood 196 product, with a yield of 97%. Example 5

[0033] Catalyst reuse 2:

[0034] Sandalwood 196 synthesis: 100 g 2-Adamantylidene propanal and 50 g methanol were added to a hydrogenation kettle, and the Cu / SiO2 catalyst recovered from Example 4 was added to the reaction system. After the feed was complete, the hydrogenation kettle was closed, and the hydrogenation kettle was replaced with nitrogen and hydrogen three times, respectively. Then, the temperature was raised to 130 degrees, 10 bar of hydrogen was introduced, and the reaction was carried out at constant temperature for 2-4 h until the residual raw material was less than 0.5%. The reaction was completed, the catalyst was filtered out, the catalyst could be reused, and the filtrate was subjected to vacuum distillation to obtain 99 g of sandalwood 196 product with a yield of 97%. Example 6

[0035] Catalyst reuse 3:

[0036] Sandalwood 196 synthesis: 100 g 2-Adamantylidene propanal and 50 g methanol were added to a hydrogenation kettle, and the Cu / SiO2 catalyst recovered from Example 5 was added to the reaction system. After the feed was complete, the hydrogenation kettle was closed, and the hydrogenation kettle was replaced with nitrogen and hydrogen three times, respectively. Then, the temperature was raised to 130 degrees, 10 bar of hydrogen was introduced, and the reaction was carried out at constant temperature for 2-4 h until the residual raw material was less than 0.5%. The reaction was completed, the catalyst was filtered out, the catalyst could be reused, and the filtrate was subjected to vacuum distillation to obtain 99 g of sandalwood 196 product with a yield of 97%.

[0037] The above embodiments are only for illustrating the technical concept and characteristics of the present application, and the purpose is to enable those skilled in the art to understand the content of the present application and implement it, and cannot limit the protection scope of the present application. Any equivalent transformation or modification made according to the spirit and essence of the present application should be covered within the protection scope of the present application.

Claims

1. Application of a Cu / SiO2 catalyst in the preparation of sandalwood 196 by catalytic hydrogenation, characterized in that: The method comprises the following steps: dissolving 2-borneolenyl propionaldehyde in an organic solvent, then adding a Cu / SiO2 catalyst to the system, heating the system to 130°C, replacing the atmosphere with nitrogen, and pressurizing the hydrogen to 10 bar to carry out a hydrogenation reaction to obtain sandalwood 196; the mass ratio of the 2-borneolenyl propionaldehyde, the organic solvent, and the Cu / SiO2 catalyst is 1:0.5:0.005; The Cu / SiO2 catalyst is prepared according to the following steps: adding a silicate and an organic amine to an ethanol solution, stirring uniformly, adjusting the pH to alkaline, and continuing to stir to obtain a silica solution, washing the silica solution with deionized water until neutral, and then dispersing it in an ethanol solution, stirring and heating, adding an ammonia solution of a copper salt to the silica ethanol solution, continuing to stir and age, washing with deionized water after aging until neutral, and vacuum drying to obtain a Cu / SiO2 catalyst; the mass ratio of copper to silica support in the prepared Cu / SiO2 catalyst is 1:41.25; The silicate is methyl orthosilicate or ethyl orthosilicate or a mixture of the two; the organic amine is one or a mixture of two or more of morpholine, tetrahydropyrrole or ethylenediamine; and the copper salt is copper chloride.

2. The use of a Cu / SiO2 catalyst according to claim 1 in the preparation of sandalwood 196 by catalytic hydrogenation, characterized in that: The mass ratio of the silicate, the organic amine and the ammonia water is (1-10):1:(1-20).

3. The use of a Cu / SiO2 catalyst according to claim 1 in the preparation of sandalwood 196 by catalytic hydrogenation, characterized in that: Stir and heat to 40-60°C, add copper salt ammonia solution, the aging temperature is 40-60°C, the aging time is 3-5h; vacuum drying temperature is 90-110°C, time is 10-14h.

4. Use of the Cu / SiO2 catalyst according to claim 1 in preparing sandalwood 196 by catalytic hydrogenation, characterized in that: The organic solvent is one or a mixture of two or more of methanol, ethanol or toluene.