CN111960911B - A kind of method for preparing cis pinane by hydrogenation of α-pinene - Google Patents

Abstract

The invention belongs to the technical field of cis-pinene preparation, and discloses a method for preparing cis-pinene by hydrogenation of α-pinene. The method is as follows: in an aqueous solution, α-pinene is charged with H ₂ under the catalysis of an amphiphilic nano-mesoporous material-supported nickel active particle catalyst Ni/CxNy@mSiO ₂ , and a catalytic hydrogenation reaction is performed to obtain cis-pinene alkyl. The catalyst Ni/CxNy@mSiO ₂ provided by the invention exhibits excellent catalytic activity and product selectivity for α-pinene hydrogenation catalytic reaction.

Description

A kind of method for preparing cis pinane by hydrogenation of α-pinene

technical field

The invention relates to a method for preparing cis-pinane by hydrogenation of α-pinene.

Background technique

my country has abundant rosin resources. Its main component, α-pinene, can be obtained by hydrogenation to obtain cis-pinene, and cis-pinene is a chemical that has important applications in the fields of biopharmaceuticals, material synthesis, industrial flavors, and pesticide synthesis. chemical intermediates. Therefore, the process of preparing cis-pinane by hydrogenation of α-pinene occupies an important position in the fields of chemical industry, biomedicine, materials, etc.; Most of the catalysts used are Pd/C, Ru/C or Raney nickel catalysts, but the reaction conditions of these catalysts are too severe, and the cis-trans ratio of cis-pinane to trans-pinane is low.

In recent years, Hou Shengli et al. used RuCl ₃ 3H ₂ O as metal precursor, polymers P123, F127 and TPGS-1000 as stabilizers, and H ₂ as reducing agent to prepare Ru nanoparticles to catalyze pinene in aqueous phase. However, this technology has problems such as difficult separation of catalyst and raw material, poor repeatability and the like. Xie Lihua et al. introduced amphiphilic functional groups into molecular sieves to prepare an amphiphilic catalyst with a "micelle-like" mechanism, and applied it to the hydrogenation of α-pinene, achieving mild, efficient, and highly selective catalytic α-α -Hydrogenation of pinene, the process has problems such as poor reusability of the catalyst, difficult separation of the catalyst and the like. At the same time, Qu Li et al. used cellulose derivatives to support metal ruthenium nanoparticles to achieve green, highly active and highly selective catalytic hydrogenation of α-pinene to prepare homeopathic pinane. Chinese patent application CN201910284586.1 discloses a method for preparing cis-pinane by hydrogenation of α-pinene, using amphiphilic magnetic nanomaterial-supported ruthenium active particles Fe ₃ O ₄ @SiO ₂ @C ₁₂ @NH ₂ /Ru as a catalyst , charged with H ₂ to catalyze the hydrogenation of α-pinene to prepare cis-pinane. However, all of the above reaction systems use precious metals such as Ru as active nanoparticles, and the cost of precious metals limits the large-scale application of catalysts. Therefore, it is an urgent task to provide a method for preparing homeopathic pinane by catalyzing the hydrogenation of α-pinene by a supported non-precious metal nanoparticle catalyst under mild conditions.

SUMMARY OF THE INVENTION

In order to solve the problems of high cost and difficult separation of noble metal catalysts in the prior art, the present invention provides a method for preparing cis-pinene by hydrogenating α-pinene.

In order to solve the above-mentioned technical problems, the present invention adopts the following technical solutions:

A method for preparing cis-pinene by hydrogenation of α-pinene. In an aqueous solution, α-pinene is charged into an amphiphilic nano-mesoporous material supported nickel active particle catalyst Ni/CxNy@mSiO ₂ under the catalysis of Ni/CxNy@mSiO 2 . Under the pressure of H ₂ , the catalytic hydrogenation reaction is carried out to obtain cis-pinane.

The molar ratio of the α-pinene provided by the present invention to the catalyst Ni/CxNy@mSiO ₂ is 1000; the reaction temperature of the catalytic hydrogenation reaction is 60-70° C., the reaction time is 2h, and the H ₂ pressure in the reaction process is 3MPa.

After the catalytic hydrogenation reaction is completed, the catalyst and the cis-pinane are separated by standing for aging and layering, and after extraction with an organic solvent such as n-heptane, the upper layer product is collected.

In the ethanol medium, the nanoparticles formed by _CxNy @mSiO2 were used as stabilizers, and the nickel particles were supported on the amphiphilic nano-mesoporous particles by the reduction and hydrogenation of nickel salts to form the nanoparticle spherical catalyst Ni/CxNy with catalytic properties. @mSiO ₂ , in this catalytic system, CxNy@mSiO ₂ can not only act as an “amphiphilic microreactor” to make the catalytic reaction proceed in the formed microenvironment, promote the progress of the reaction and improve the catalytic efficiency, but also provide Amphiphilicity is crucial for catalyst separation.

Considering the relatively high cost of the catalyst-supported precious metal, the inventor selected non-precious metal as the supported metal atom. However, the non-precious metal active particle catalyst supported by the amphiphilic nano-mesoporous material provided by the present invention is relatively strict in the selection of non-precious metal, and the non-precious metal in the catalytic system is very strict. The noble metal nickel (Ni) makes the catalyst show more excellent catalytic activity and product selectivity, and its performance is obviously better than that of other non-precious metals. The metal atoms supported by the catalyst are different, and the ability of adsorbing and cracking hydrogen molecules is different. The activities of the hydrogenation reaction are different. In the amphiphilic environment provided by the catalyst carrier CxNy@mSiO ₂ , the Ni-based catalyst has the fastest adsorption rate of hydrogen, and the activity energy required for cracking hydrogen molecules is lower; in addition, in the preparation of the catalyst, It is found that the carrier CxNy@mSiO ₂ can immobilize more Ni nanoparticles, so that Ni/CxNy@mSiO ₂ has more catalytic active centers, which is also an obvious advantage. The experimental data show that the Ni-based catalyst provided by the present invention finally presents Good catalytic activity and product selectivity were obtained.

In the catalytic hydrogenation reaction, the solid catalyst-α-pinene oil phase-hydrogen forms a three-phase interface, which reduces the mass transfer resistance and is conducive to the reaction, so that the catalytic hydrogenation reaction can be carried out under mild conditions. Mild reaction conditions The catalyst has higher catalytic efficiency and better selectivity for α-pinene, but the catalytic efficiency decreases when the temperature is too high, mainly because the excessively high temperature destroys the three-phase interface of the reaction and causes the catalytic activity to decrease. The effective catalytic temperature of the catalyst is 60-70°C. In addition, after the reaction is completed, the catalyst is separated by standing and stratified, the catalyst can be reused, and the recovered catalyst can still maintain its activity.

Another object of the present invention is to provide a method for preparing the catalyst Ni/CxNy@mSiO ₂ , which uses resorcinol and formaldehyde as carbon sources, ethylenediamine as nitrogen source, and hexadecyltrimethyl bromide. Ammonium is used as a template agent, ethyl orthosilicate is used as a silicon source, and an amphiphilic core-shell nano-mesoporous material CxNy@mSiO ₂ is synthesized by carbonization at high temperature. Finally, nickel particles are supported on the amphiphilic nano-mesoporous material through reduction and hydrogenation of nickel salts. On the porous core-shell material, a stable catalyst Ni/CxNy@mSiO ₂ is formed.

The preparation method of the catalyst Ni/CxNy@mSiO ₂ is as follows:

1) Preparation of hollow Juans amphiphilic nano-mesoporous material CxNy@mSiO ₂ Weigh 0.16g CTAB (hexadecyltrimethylammonium bromide) and 5mL EDA (ethylenediamine) and disperse them in 50mL ethanol and water respectively 0.12g of resorcinol was added to the mixed solution, ultrasonically dispersed for 30min, 0.24mL of formaldehyde was added dropwise, stirred for 2h, then 50mg of CTAB was added, 0.8mLTEOS (ethyl orthosilicate) was added dropwise, and the stirring was continued for 12h, then The amphiphilic nano-mesoporous material CxNy@mSiO ₂ was obtained by standing and aging for 48h, centrifuging, and finally carbonizing at high temperature in an argon atmosphere;

2) Preparation of hollow Juans amphiphilic nano-mesoporous material-supported nickel active particle catalyst Ni/CxNy@mSiO ₂ Weigh 50mg CxNy@mSiO ₂ into a 100mL single-neck flask, ultrasonically disperse it in ethanol solution at room temperature, and then add 30mg NiCl _2. Continue to disperse for 10 min, then weigh 30 mg of NaBH ₄ and add it to a 10 mL centrifuge tube, add 8 mL of ethyl acetate solution to dissolve it completely, drop the dissolved liquid into a single-neck flask, and stir magnetically at 40 °C for 2 hours to obtain Catalyst Ni/CxNy@mSiO ₂ .

Preferably, the volume ratio of ethanol and water in the mixed solution of ethanol and water is 3:7.

The invention provides a method for preparing cis-pinane by hydrogenation of α-pinene. In the method provided by the invention, the use of hollow Juans amphiphilic nano-mesoporous material to support nickel active particle catalyst Ni/CxNy@mSiO ₂ shows better performance. The catalytic activity and product selectivity of α-pinene, and the various reaction conditions of the synergistic catalytic hydrogenation reaction make the conversion rate of α-pinene and the selectivity of cis-pinene reach the best.

Detailed ways

The invention discloses a method for preparing cis-pinene by hydrogenation of α-pinene, which can be achieved by those skilled in the art by appropriately improving the process parameters for reference. It should be particularly pointed out that all similar substitutions and modifications are obvious to those skilled in the art, and they are deemed to be included in the present invention. The method and application of the present invention have been described through the preferred embodiments, and it is obvious that relevant persons can make changes or appropriate changes and combinations of the methods and applications described herein without departing from the content, spirit and scope of the present invention to achieve and Apply the technology of the present invention.

In order to enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to specific embodiments.

Example ₁ Preparation of catalyst Ni/CxNy@mSiO2

S ₁ . Preparation of hollow Juans amphiphilic nano-mesoporous material (CxNy@mSiO ₂ ): Weigh 0.16g CTAB (hexadecyltrimethylammonium bromide) and 5mL EDA (ethylenediamine) and disperse them in 50mL of a mixed solution of ethanol and water (ethanol:water=3:7), add 0.12g of resorcinol, ultrasonically disperse for 30min, dropwise add 0.24mL of formaldehyde, stir and react for 2h, then add 50mg CTAB, dropwise add 0.8 mL TEOS (ethyl orthosilicate), continue to stir for 12h, then stand for 48h, centrifuge, and finally carbonize at high temperature under argon atmosphere to obtain the amphiphilic nano-mesoporous material CxNy@mSiO ₂ ;

S ₂ , preparation of hollow Juans amphiphilic nanocatalyst (Ni/CxNy@mSiO ₂ ): weigh 50 mg of CxNy@mSiO ₂ into a 100 mL one-neck flask, ultrasonically disperse it in ethanol solution at room temperature, then add 30 mg of NiCl ₂ , and continue Disperse for 10min, then weigh 30mg NaBH ₄ into a 10mL centrifuge tube, add 8mL ethyl acetate solution to dissolve it completely, add the dissolved liquid dropwise to a single-neck flask, and magnetically stir at 40°C for 2h, the stability can be obtained. The amphiphilic nanocatalyst Ni/CxNy@mSiO ₂ .

The synthesized amphiphilic nano-mesoporous material CxNy@mSiO ₂ is scanned by scanning electron microscope and transmission electron microscope. It can be clearly seen that the catalyst carrier prepared by the present invention has uniform size and particle size, and has a relatively large specific surface area, which can increase the amount of substrate and catalyst. contact area to promote the reaction. The synthesized amphiphilic nanocatalyst Ni/ _CxNy @mSiO2 was scanned by high-resolution transmission electron microscope, and the lattice fringes of the metal nanoparticle nickel (Ni) supported by the amphiphilic nanocatalyst Ni/ _CxNy @mSiO2 can be clearly seen .

Example 2 Hydrogenation of α-pinene to prepare cis-pinene

Weigh 1g of α-pinene and add it to the stainless steel mechanical stirring kettle, then add 4mL of water, weigh 20mg of amphiphilic catalyst and mix it well, replace the gas in the kettle with 1MPa hydrogen for 4 times, then pour 3MPa hydrogen into it, at 60 ℃ The reaction was mechanically stirred for 2 hours. After the reaction was completed, the catalyst and the product were separated by standing. After extraction with n-heptane, the upper product phase was collected and subjected to quantitative analysis by chromatography. The selectivity was 96.5%.

Example 3 Hydrogenation of α-pinene to prepare cis-pinene

Weigh 1g of α-pinene and add it to the stainless steel mechanical stirring kettle, then add 4mL of water, weigh 20mg of amphiphilic catalyst and mix it well, replace the gas in the kettle with 1MPa hydrogen for 4 times, then pour in 3MPa hydrogen, at 70°C The reaction was mechanically stirred for 2 hours. After the reaction was completed, the catalyst and the product were separated by standing. After extraction with toluene, the upper product phase was collected and subjected to quantitative analysis by chromatography. The conversion rate of α-pinene was 97.1%, and the selectivity of cis-pinene was 97.1%. is 98.5%.

The reuse of embodiment 4 catalyst

Weigh 1g of α-pinene and add it to the stainless steel autoclave, then add 4mL of water, weigh 20mg of the amphiphilic nanocatalyst and mix evenly, replace the gas in the kettle with 1MPa hydrogen for 4 times, then pour in 3MPa hydrogen, at 60°C The reaction was carried out under mechanical stirring for 2 h. After the reaction, the catalyst was separated from the product. The separated catalyst was reused. The above experimental steps were repeated. The catalyst was reused 7 times. It is 96.5%, indicating that the catalyst has good reuse performance.

Example 5 Selection of temperature for preparing cis-pinane by hydrogenation of α-pinene

Weigh 1g of α-pinene and add it to the stainless steel mechanical reaction kettle, then add 4mL of water, weigh 20mg of amphiphilic nanocatalyst and mix evenly, replace the gas in the kettle with 1MPa hydrogen for 4 times, then pour in 3MPa hydrogen, at 100°C The reaction was carried out under magnetic stirring for 1 h. After the reaction was completed, the catalyst and the substrate were separated by standing. After extraction with n-heptane, the upper product phase was collected and quantitatively analyzed by chromatography. The conversion rate of α-pinene was 24.5%. The selectivity of alkane is 96.6%; if the temperature is too high, the catalytic efficiency decreases, mainly because the high temperature destroys the three-phase interface of the reaction, resulting in the decrease of catalytic activity. The effective catalytic temperature of the catalyst is 60-70 °C.

Comparative ratio

Add 1g α-pinene, 20mg of a different catalyst and 4mL of water into a stainless steel mechanical reaction kettle, mix well, replace it with 1MPa hydrogen for 4 times, then pour in 3MPa hydrogen, and conduct a magnetic stirring reaction at 60°C for 2h, the reaction ends. Then, the catalyst and the product were separated by centrifugation, the product phase was extracted with n-heptane, and the quantitative analysis of the product was carried out by chromatography.

Table 1 Effects of different catalysts on the catalytic hydrogenation of α-pinene

The data in Table 1 shows that the catalyst designed by the present invention, when using hydrogen as a reducing agent, under the same conditions, exhibits excellent catalytic activity and product selectivity for the α-pinene hydrogenation catalytic reaction, and its effect is obviously better than that of other catalysts. The non-precious metal catalyst is also significantly better than the industrial Reny Ni catalyst; at the same time, it is better than the noble metal catalyst Pd/C in selectivity.

The non-precious metal atom Ni supported by the catalyst provided by the present invention has a strong ability of adsorbing and cracking hydrogen molecules. Under the amphiphilic environment provided by the catalyst carrier CxNy@mSiO ₂ , the Ni-based catalyst has the fastest ability and speed of adsorbing hydrogen and cracking hydrogen. The activity energy required by the molecule is lower, and at the same time, the carrier CxNy@mSiO ₂ can immobilize more Ni nanoparticles, so that Ni/CxNy@mSiO ₂ has more catalytic active centers; therefore, the catalyst Ni/CxNy@mSiO 2 provided by the present invention CxNy@mSiO2 exhibits excellent catalytic activity and product selectivity for the _{hydrogenation} of α-pinene.

The above are only the preferred embodiments of the present invention. It should be pointed out that for those skilled in the art, without departing from the principles of the present invention, several improvements and modifications can be made. It should be regarded as the protection scope of the present invention.

Claims (6)

1. A method for preparing cis-pinane by hydrogenating alpha-pinene is characterized in that in aqueous solution, the alpha-pinene is loaded with a nickel active particle catalyst Ni/C in an amphiphilic nano mesoporous materialxNy@mSiO₂Under the catalytic action of (3), fill pressure H₂Performing catalytic hydrogenation reaction at 60-70 ℃ to obtain cis-pinane₂The pressure is 3 MPa; the catalyst Ni/CxNy@mSiO₂The preparation method specifically comprises the following steps:

1) hollow amphiphilic nano mesoporous material CxNy@mSiO₂Preparation of (1) 0.16g CTAB (cetyltrimethylammonium bromide) and 5mL ED were weighed out separatelyDispersing A (ethylenediamine) in 50mL of mixed solution of ethanol and water, adding 0.12g of resorcinol, performing ultrasonic dispersion for 30min, dropwise adding 0.24mL of formaldehyde, stirring for reacting for 2h, adding 50mg of CTAB, dropwise adding 0.8mL of TEOS (tetraethoxysilane), continuing stirring for 12h, standing and aging for 48h, performing centrifugal separation, and finally carbonizing at high temperature in argon atmosphere to obtain the amphiphilic nano mesoporous material CxNy@mSiO₂；

2) The catalyst Ni/CxNy @ mSiO is a catalyst of hollow amphiphilic nano mesoporous material loaded with nickel active particles₂Preparation 50mg of CxNy@mSiO₂Adding into a 100mL single-neck flask, ultrasonically dispersing in ethanol solution at room temperature, and adding 30mg NiCl₂Continuously dispersing for 10min, and then weighing 30mg NaBH₄Adding the solution into a 10mL centrifuge tube, adding 8mL ethyl acetate solution to completely dissolve the solution, dropwise adding the dissolved liquid into a single-neck flask, and magnetically stirring the solution at 40 ℃ for 2 hours to obtain the catalyst Ni/CxNy @ mSiO₂。

2. The method for preparing cis-pinane by hydrogenating alpha-pinene according to claim 1, wherein the alpha-pinene and the catalyst Ni/C arexNy@mSiO₂In a mass ratio of 50: 1.

3. The method for preparing cis-pinane by hydrogenating alpha-pinene according to claim 1, wherein the reaction time of the catalytic hydrogenation reaction is 2 hours.

4. The method for preparing cis-pinane by hydrogenating alpha-pinene according to claim 1, wherein after the catalytic hydrogenation reaction is finished, the catalyst is separated from the cis-pinane by standing, aging and layering.

5. The method for preparing cis-pinane by hydrogenating alpha-pinene according to claim 1, wherein the catalyst Ni/CxNy@mSiO₂The preparation method comprises adopting resorcinol and formaldehyde as carbon source, ethylenediamine as nitrogen source, cetyl trimethyl ammonium bromide as template agent, and ethyl orthosilicate as template agentAs a silicon source, synthesizing the amphiphilic core-shell nano mesoporous material C by high-temperature carbonizationxNy@mSiO₂Finally, nickel particles are loaded on the amphiphilic nano mesoporous core-shell material through nickel salt reduction hydrogenation to form a stable catalyst Ni/CxNy@mSiO₂。

6. The method for preparing cis-pinane by hydrogenating alpha-pinene according to claim 1, wherein the volume ratio of ethanol to water in the mixed solution of ethanol and water is 3: 7.