阅读说明：本技术 一种回路反应器中炔醇选择性加氢制烯醇的方法 (Method for preparing enol by selective hydrogenation of alkynol in loop reactor ) 是由 马啸 张玉霞 于明 姜晓阳 李庆辉 马慧娟 于 2020-04-29 设计创作，主要内容包括：本发明提供一种回路反应器中炔醇选择性加氢制烯醇的方法,将炔醇和钙钛矿型复合氧化物催化剂投入回路反应器中,在一定H<Sub>2</Sub>压力和温度下进行选择性氢化反应,反应结束后过滤催化剂,得到对应的烯醇。本发明催化效率高,选择性好,收率高达98%；本发明传质效率高,转化速度快,反应时间仅需要20-40min；本发明催化体系简单,可简化后续分离步骤,降低能耗成本；本发明反应条件温和,安全性高；本发明所用催化剂价格便宜、用量少,降低了生产成本；本发明催化剂稳定性好,套用多批仍保持较高性能。(The invention provides a method for preparing enol by selective hydrogenation of alkynol in a loop reactor, which comprises the steps of putting the alkynol and a perovskite type composite oxide catalyst into the loop reactor, and reacting at a certain H 2 Carrying out selective hydrogenation reaction under pressure and temperature, and filtering the catalyst after the reaction is finished to obtain the corresponding enol. The invention has high catalytic efficiency, good selectivity and high yield up to 98 percent; the invention has high mass transfer efficiency and high conversion speed, and the reaction time is only 20-40 min; the invention has simple catalytic system, can simplify the subsequent separation steps and reduce the energy consumption cost; the invention has mild reaction conditions and high safety; the catalyst used in the invention has low price and low dosage, and reduces the production cost; the catalyst of the present inventionGood stability, and can maintain high performance even if applied in multiple batches.)

1. A method for preparing enol by selective hydrogenation of alkynol in loop reactor is characterized by that alkynol and perovskite type composite oxide catalyst are put into loop reactor and put in a certain H₂Selective hydrogenation is carried out under pressure and temperature to obtain the corresponding enol.

2. The method as claimed in claim 1, wherein the perovskite-type composite oxide catalyst is L a_1-mM_mMn_1-nPd_nO₃₊；

M is selected from one of Y, Ce and Pr; wherein m is 0.05-0.5, and n is 0.02-0.05.

3. The method for preparing an enol according to claim 1, wherein said alkynol has a formula

；

Wherein R1 and R2 are hydrogen or alkyl.

4. The process according to claim 1 or 3, wherein the alkynol is selected from 2-methyl-3-butyn-2-ol, dehydrolinalool, dihydrodehydrolinalool, dehydronerolidol, dihydrodehydronerolidol, tetrahydrodehydronerolidol or dehydroisophytol.

5. The method of claim 1, wherein the catalyst is present in an amount of 0.05% to 0.1% by weight of the alkynol in the selective hydrogenation.

6. The process according to claim 1, wherein H is the product of the selective hydrogenation of the alkynol to produce the enol₂The pressure is 0.1-0.5 MPa; the reaction temperature is 30-50 ℃.

7. The process according to claim 1, wherein the selective hydrogenation is carried out for a period of 20-40 min.

8. The method for preparing an enol according to claim 1, wherein the perovskite-type composite oxide catalyst is prepared by the following steps:

weighing salt of each active component in the catalyst according to the stoichiometric ratio, adding the salt into distilled water, adding citric acid, fully dissolving, stirring and evaporating to dryness until the solution is in a sol state, and roasting a sample at the temperature of 600-800 ℃ after drying to obtain the perovskite type composite oxide catalyst.

9. The method for preparing an enol by selective hydrogenation of alkynol in the loop reactor according to claim 9, wherein the temperature for stirring and evaporating to dryness is 75-85 ℃, and the drying temperature is 80-120 ℃.

10. The process according to claim 9, wherein the molar ratio of metal cation to citric acid in the catalyst is 1: 1.0-1.2; the salt is nitrate, acetate, chloride or oxalate.

Technical Field

The invention relates to a method for producing vitamin E, vitamin A, vitamin K1, carotenoid intermediates, DV chrysanthemic acid (pyrethroid intermediates) and synthesizing spices, in particular to a continuous synthesis method for preparing enol by selective hydrogenation of alkynol in a loop reactor, belonging to the technical field of organic chemical industry.

Background

The enol has wide application in fine chemical industry, and is mainly used for producing vitamin E, vitamin A, vitamin K1, carotenoid intermediates, DV chrysanthemic acid (pyrethroid intermediates), synthetic perfumes and the like. The selective hydrogenation of alkynols (formula I) to the corresponding enols (formula II) is a widely used technical route in industry.

The general reaction formula is as follows:

wherein R1 and R2 are hydrogen or alkyl.

The catalyst used in the actual production is mainly Lindla (L indlar) catalyst, which is CaCO₃Or BaSO₄The supported catalyst takes Pd with the weight content of 5-10 wt.% as an active component and is poisoned by lead acetate and the like. However, the Pd content is high and the price is high, and with the stricter and stricter environmental regulations, the treatment of the Pb metal in the deactivated catalyst has great difficulty.

CN106345508B discloses that 0.1-5% of PdX/CN @ ZnO (X is Bi, Mn or Ag) catalyst is used for selective hydrogenation of C5-C20 alkynol, the conversion rate of the alkynol is 99.5% and the selectivity of corresponding enol can reach 98% under the conditions that the reaction temperature is 30-85 ℃, the pressure is 1.0-2.0MPa, the mass ratio of the catalyst to the alkynol is 0.3-0.4%, and a solvent ethanol or water exists. The catalyst avoids the addition of metal Pb and has high selectivity, but the reaction pressure is high and the use of a solvent increases the burden of a product separation process. In the technical scheme of CN109317175A, Pd loaded on a high-dispersion indium oxide composite nitrogen-doped porous carbon material serving as a carrier is used as an alkynol selective hydrogenation catalyst, and the reaction is carried out for 2 hours at the reaction temperature of 30 ℃ and the pressure of 1.0MPa in the presence of solvent ethanol, wherein the alkynol conversion rate is 100%, and the selectivity of corresponding enol can reach 98%. However, the reaction pressure of the system is higher, and the reaction time is longer.

Disclosure of Invention

The technical problem to be solved by the invention is to overcome the defects in the prior art and provide the method for preparing the enol by selective hydrogenation of the alkynol, which has the advantages of high yield, cheap catalyst, small dosage, high stability, mild reaction condition and short reaction time.

Therefore, the invention adopts the following technical scheme:

a process for preparing enol by selective hydrogenation of alkynol in loop reactor includes such steps as loading alkynol and perovskite-type composite oxide catalyst in loop reactor, and reacting in certain reactor at certain temp₂Selective hydrogenation is carried out under pressure and temperature to obtain the corresponding enol.

The perovskite type composite oxide catalyst is L a_1-mM_mMn_1-nPd_nO₃₊；

M is selected from one of Y, Ce and Pr; wherein m is 0.05-0.5, and n is 0.02-0.05.

The structural formula of the alkynol is shown as a formula (I); the structural formula of the enol is shown as a formula (II);

wherein R1 and R2 are hydrogen or alkyl.

The alkynol is selected from 2-methyl-3-butyn-2-ol, dehydrolinalool (3, 7-dimethyl-6-octen-1-yn-3-ol), dihydrodehydrolinalool (3, 7-dimethyl-1-octen-3-ol), dehydronerolidol (3, 7, 11-trimethyl-6, 10-dodecadien-1-yn-3-ol), dihydrodehydronerolidol (3, 7, 11-trimethyl-6-dodecen-1-yn-3-ol), tetrahydrodehydronerolidol (3, 7, 11-trimethyl-1-dodecyn-3-ol) or dehydroisophytol (3, 7,11, 15-tetramethyl-1-hexadecyn-3-ol).

The mass percentage of the catalyst in the selective hydrogenation reaction is 0.05-0.1% of the alkynol.

H of selective hydrogenation₂The pressure is 0.1-0.5 MPa.

The temperature of the selective hydrogenation reaction is 30-50 ℃.

The time of the selective hydrogenation reaction is 20-40 min.

The catalyst obtained by filtering can be used mechanically, and the test result shows that the activity and the selectivity of the catalyst are not obviously reduced after 50 times of use.

The perovskite type composite oxide catalyst can be prepared by adopting the following method:

weighing salt of each active component in the catalyst according to the stoichiometric amount, adding the salt into distilled water, adding citric acid, fully dissolving, stirring and evaporating to dryness in a water bath at the temperature of 75-85 ℃ to a sol state, placing the sol state in an oven for drying, and roasting a sample at the temperature of 600-800 ℃ to form a perovskite structure.

The drying temperature is 80-120 ℃;

the molar ratio of the metal cations to the citric acid in the catalyst is 1: 1.0-1.2; the salt is nitrate, acetate, chloride or oxalate.

The general structural formula of the perovskite oxide can be represented as ABO₃When the A site and the B site are partially substituted by different ions, perovskite with a complex structure is formed, and then ion defects may be caused due to the valence sum not satisfying 6, which is expressed as AA 'BB' O₃₊。

By adopting the technical scheme, compared with the prior art, the invention has the following beneficial effects:

(1) the invention has high catalytic efficiency, good selectivity, high yield up to more than 98%, conversion rate of alkynol of 99.5-99.8% and selectivity of 98.5-98.6%.

(2) The invention has high mass transfer efficiency and high conversion speed, and the reaction time is only 20-40 min.

(3) The invention avoids the use of solvent, simplifies the subsequent separation steps and reduces the energy consumption cost.

(4) The invention has mild reaction condition, high safety and low reaction pressure.

(5) The catalyst used in the invention has low price and low dosage, and reduces the production cost.

(6) The catalyst has good stability, can still maintain high performance even if being applied in multiple batches, can be continuously applied in 50 batches, and has the conversion rate fluctuation of +/-0.2 percent and the selectivity fluctuation of +/-0.1 percent.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below by way of examples. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

The embodiment of the invention provides a method for preparing enol by selectively hydrogenating alkynol in a loop reactor, which comprises the steps of putting the alkynol and a perovskite type composite oxide catalyst into the loop reactor, and reacting at a certain H₂Carrying out selective hydrogenation reaction under pressure and temperature, and filtering the catalyst after the reaction is finished to obtain the corresponding enol.

The embodiment of the invention provides a method for preparing enol by selective hydrogenation of alkynol in a loop reactor, which adopts a perovskite type composite oxide catalyst L a_1-mM_mMn_1-nPd_nO₃₊While incorporating a loop reactorThe mass transfer efficiency and the heat exchange efficiency are greatly enhanced, the high-selectivity hydrogenation of the alkynol to the enol can be realized in a short time at a lower temperature and a lower pressure, and the method is suitable for large-scale production.

The perovskite type composite oxide is a quaternary perovskite composite oxide with a structural formula of L a_1-mM_mMn_1-nPd_nO₃₊Wherein M is any one of Y, Ce and Pr, and M can be any value in the range of 0.05, 0.075, 0.1, 0.125, 0.15, 0.175, 0.2, 0.225, 0.25, 0.275, 0.3, 0.325, 0.35, 0375, 0.4, 0.425, 0.45, 0.475, 0.5 and 0.05-0.5. n may be any value within the range of 0.02, 0.025, 0.03, 0035, 0.04, 0.045, 0.05, 0.02 to 0.05.

The loop reactor of the invention is a loop reactor well known to those skilled in the art, and consists of a high-pressure reaction kettle, a loop circulating pump, an external heat exchanger and a Venturi ejector. When the reactor works, the circulating pump is started, the liquid mixed catalyst and the gas circulate in the loop at a large flow rate, the liquid mixed catalyst and the gas are ejected at a high speed in the Venturi ejector, the reaction in the reactor is sucked by negative pressure in the gas chamber, and the gas and the liquid containing the catalyst are mixed violently and react efficiently in the impact zone. The use of the loop reactor can enhance the mass and heat transfer rate, improve the productivity and the reaction selectivity, and simultaneously meet the requirements of safety, health and environmental protection of chemical enterprises.

The structural formula of the alkynol is shown as a formula (I); the structural formula of the enol is shown as a formula (II);

wherein R1 and R2 are hydrogen or alkyl.

Typical compounds of the alkynols are: 2-methyl-3-butyn-2-ol, dehydrolinalool, dihydrodehydrolinalool, dehydronerolidol, dihydrodehydronerolidol, tetrahydrodehydronerolidol or dehydroisophytol.

The structure is as follows:

the corresponding selective hydrogenation product enol is: 2-methyl-3-buten-2-ol, linalool, dihydrolinalool, nerolidol, dihydronerolidol, tetrahydronerolidol or isophytol.

The structure is as follows:

the perovskite type composite oxide catalyst can be prepared by the following method, a certain amount of mixed salt with any combination is weighed according to the stoichiometric amount, then a proper amount of citric acid is weighed, the citric acid is added into distilled water, the dissolution of the citric acid is promoted by adopting ultrasonic oscillation, the mixture is stirred and evaporated to dryness in a water bath at 80 ℃ to a sol state, the mixture is placed in a drying oven at 80-120 ℃ for drying, and then a sample is roasted at 600-800 ℃, so that a perovskite structure is formed.

In some embodiments, the metal salt may be a nitrate, acetate, chloride, or oxalate salt of the corresponding metal. For example, the palladium salt may be one or more of palladium nitrate, palladium acetate, palladium chloride, or palladium oxalate.

In some embodiments, the temperature of the drying step may be 80 ℃ to 120 ℃, and the drying time may be 4 hours to 24 hours. When the drying temperature is low, the drying time can be properly prolonged; when the drying temperature is high, the drying time may be suitably short, for example, when the drying temperature is 120 ℃, the drying time may be 4 hours. The purposes of removing adsorbed water, obtaining a certain pore structure and mechanical strength and the like are realized through drying.

In some embodiments, the temperature of the baking step may be 600 ℃ to 800 ℃, and the baking time may be 3 hours to 6 hours. When the roasting temperature is low, the roasting time can be properly long; when the calcination temperature is high, the calcination time may be suitably short, and for example, when the calcination temperature is 800 ℃, the calcination time may be 3 hours. The purposes of removing moisture, decomposing precursor salt, improving mechanical strength, enhancing interaction among metal carriers, forming a perovskite structure and the like are realized through roasting.

Compounding the perovskite typeThe oxide is used as catalyst and alkynol is put into a loop reactor at a certain H₂Selective hydrogenation is carried out under pressure and temperature to obtain the corresponding enol.

In some embodiments, the mass ratio of the perovskite-type composite oxide catalyst to the alkynol is 0.05% to 0.1%, and the mass ratio of the catalyst to the alkynol may be any ratio within the range of the ratio, such as 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%.

In some embodiments, the above-described selective hydrogenation of H₂The pressure is 0.1-0.5MPa, the temperature is 30-50 ℃, and the reaction time is 20-40 min.

The following are specific examples.