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CN-121991010-A - Production and preparation method of whiskey lactone

CN121991010ACN 121991010 ACN121991010 ACN 121991010ACN-121991010-A

Abstract

The invention relates to the technical field of organic synthesis, and particularly discloses a production and preparation method of whiskey lactone. Dissolving methyl crotonate, n-valeraldehyde and sodium ethoxide in absolute ethyl alcohol, continuously pumping raw material liquid into a microtube reactor with preset temperature through a peristaltic pump to react to obtain effluent liquid, mixing the effluent liquid with hydrogen, continuously introducing the mixture into a micro-packed bed reactor with a modified palladium-carbon catalyst to perform hydrogenation reaction, and cooling, gas-liquid separation and reduced pressure rectification of the reaction product to obtain a whiskey lactone product. The modified palladium-carbon catalyst is prepared by modifying a hydroxyapatite carrier by a composite oxide modifier, loading palladium and reducing. The invention adopts a process combining continuous micro-reaction and fixed bed hydrogenation, and utilizes a specific catalyst, thereby remarkably improving the reaction efficiency and the product yield, and having the advantages of good selectivity, high catalyst stability, continuous and controllable process and safe operation.

Inventors

  • ZHANG ZHENG
  • WANG YANG
  • DONG JINLONG

Assignees

  • 安徽华业香料股份有限公司

Dates

Publication Date
20260508
Application Date
20260227

Claims (8)

  1. 1. The production and preparation method of whiskey lactone is characterized by comprising the following steps: (1) Dissolving methyl crotonate, n-valeraldehyde and sodium ethoxide in absolute ethyl alcohol to obtain a raw material liquid, pumping the raw material liquid into a micro-tubular reactor for reaction, and obtaining effluent after the reaction is finished; (2) Filling a modified palladium-carbon catalyst into a micro-packed bed reactor to form a fixed catalytic bed layer, uniformly mixing the effluent liquid obtained in the step (1) with hydrogen, continuously feeding the mixture into the micro-packed bed reactor for catalytic reaction, cooling a reaction product, separating gas from liquid, performing vacuum distillation on the obtained liquid product, and collecting corresponding fractions to obtain the whiskey lactone product.
  2. 2. The method for producing and preparing whiskey lactone according to claim 1, wherein the step of preparing the modified palladium-carbon catalyst in the step (2) comprises the steps of: S1, dissolving dysprosium nitrate, cerium nitrate and urea in deionized water, reacting at constant temperature and constant pressure, separating, drying, roasting and grinding to obtain a composite oxide modifier; s2, mixing hydroxyapatite powder, a composite oxide modifier and absolute ethyl alcohol, performing ultrasonic dispersion to obtain a dispersion liquid, and performing rotary steaming, roasting and grinding to obtain a composite oxide modified carrier; S3, dispersing the composite oxide modified carrier and palladium chloride in deionized water, regulating the pH value, stirring and adsorbing, adding a reducing agent for reduction reaction, and filtering, washing and drying the product to obtain the modified palladium-carbon catalyst.
  3. 3. The production and preparation method of whiskey lactone according to claim 1, wherein in the step (1), 30-35 parts by weight of methyl crotonate, 35-40 parts by weight of n-valeraldehyde, 0.5-0.6 part by weight of sodium ethoxide and 90-100 parts by weight of absolute ethyl alcohol are calculated.
  4. 4. The production and preparation method of whiskey lactone according to claim 1, wherein 3-4 parts of modified palladium-carbon catalyst is filled in the micro-packed bed reactor in the step (2), the hydrogen pressure of the reaction system is controlled to be 1.5MPa, the temperature of the reaction area is controlled to be 90-100 ℃, and the residence time of materials in the catalytic bed is 5-10min.
  5. 5. The method for producing and preparing whiskey lactone according to claim 1, wherein the temperature of the fraction collected by vacuum distillation in the step (2) is 90-96 ℃, and the effluent and hydrogen are introduced into a static mixer for homogeneous mixing before entering the micro-packed bed reactor.
  6. 6. The method for producing and preparing whiskey lactone according to claim 2, wherein in the step S1, 10-15 parts by weight of dysprosium nitrate, 18-22 parts by weight of cerium nitrate, 22-26 parts by weight of urea, and 100-110 parts by weight of deionized water are calculated.
  7. 7. The production and preparation method of whiskey lactone according to claim 2, wherein in the step S2, 30-35 parts by weight of hydroxyapatite powder, 8-12 parts by weight of a composite oxide modifier, and 95-100 parts by weight of absolute ethyl alcohol are calculated.
  8. 8. The production and preparation method of whiskey lactone according to claim 2, wherein in the step S3, 10-15 parts by weight of the composite oxide modified carrier, 0.6-0.9 part by weight of palladium chloride and 25-30 parts by weight of deionized water are calculated, the reducing agent is sodium formate aqueous solution, and the reduction reaction temperature is 80-90 ℃.

Description

Production and preparation method of whiskey lactone Technical Field The invention relates to the technical field of organic synthesis, in particular to a production and preparation method of whiskey lactone. Background Whiskey lactone is an important spice compound which naturally exists in whiskey wine and oak, has unique coconut and cream fragrance, and is widely applied to high-grade formulas of foods, wines and tobacco essences. The chemical structure of the gamma-lactone derivative comprises cis and trans isomers, wherein the cis isomer is usually a dominant aroma contributor. Traditional methods for synthesizing whiskey lactones rely mainly on multi-step reaction pathways starting from n-valeraldehyde and crotonic acid, which generally involve critical steps such as free radical addition, reduction and cyclization. In the early reported synthesis process, excessive n-valeraldehyde and crotonic acid are required to undergo free radical addition reaction under the action of an initiator and a cocatalyst to generate an intermediate keto acid, then reduction is realized by a chemical reducing agent such as sodium borohydride, and finally the target product is obtained through dehydration cyclization under an acidic condition. In the method, the reaction is carried out in a large amount of organic solvent, so that the cost is high, side reactions are increased, the product selectivity is poor, and the like. In addition, the cyclization step generates a large amount of acid-containing wastewater, the subsequent treatment process is complex, the environmental pollution pressure is high, and the overall reaction efficiency and the atom economy are low. In recent years, although an improved process adopts crotonate to replace crotonic acid as a raw material, an acidic environment is avoided, and catalytic hydrogenation is utilized to replace chemical reduction, so that the reaction mildness and the raw material utilization rate are improved to a certain extent. However, the method still adopts batch reactors, has the limitations of low mass and heat transfer efficiency, insufficient control precision of reaction parameters, obvious process amplification effect and the like, and influences the reaction rate, the product yield and the process safety. Meanwhile, the activity, stability and reusability of the catalyst are still further improved. Therefore, the invention provides a production and preparation method of whiskey lactone, which aims to solve the technical problems. Disclosure of Invention The invention aims to provide a production and preparation method of whiskey lactone, which adopts a process of combining continuous micro-reaction and fixed bed hydrogenation, and utilizes a specific catalyst to remarkably improve the reaction efficiency and the product yield, and has the advantages of good selectivity, high catalyst stability, continuous and controllable process and safe operation. The invention provides a production and preparation method of whiskey lactone, which adopts the following technical scheme: (1) Dissolving 30-35 parts of methyl crotonate, 35-40 parts of n-valeraldehyde and 0.5-0.6 part of sodium ethoxide in 90-100 parts of absolute ethyl alcohol, pumping the raw materials into a microtube reactor with the preset temperature of 80-90 ℃ through a peristaltic pump, controlling the residence time in the reactor to be 20-25min, and obtaining effluent after the reaction is finished; (2) Filling 3-4 parts of modified palladium-carbon catalyst into a micro-packed bed reactor to form a fixed catalytic bed layer, continuously introducing the effluent liquid obtained in the step (1) and hydrogen into a static mixer for full homogeneous mixing, continuously feeding the mixed material system into the micro-packed bed reactor filled with the modified palladium-carbon catalyst, controlling the hydrogen pressure of the reaction system to be 1.5MPa, maintaining the temperature of a reaction area to be 90-100 ℃, controlling the residence time of the material in the catalytic bed layer to be 5-10min through regulating the flow rate of the material, performing reduced pressure rectification on the obtained liquid product after cooling treatment and gas-liquid separation, and collecting 90-96 ℃ fractions, namely whiskey lactone products. Preferably, the preparation steps of the modified palladium carbon catalyst in the step (2) are as follows: S1, dissolving 10-15 parts of dysprosium nitrate, 18-22 parts of cerium nitrate and 22-26 parts of urea in 100-110 parts of deionized water, reacting for 4-6 hours at a constant temperature and a constant pressure of 150-160 ℃, 0.7-0.9MPa and 280-340rpm, filtering, washing, detecting no nitrate, vacuum drying, transferring into a muffle furnace, roasting for 4-5 hours at a temperature of 3 ℃ per minute to 640-660 ℃, cooling, and grinding to a particle size of 300 meshes to obtain the composite oxide modifier; S2, mixing 30-35 parts of hydroxyapatite powder, 8-12 parts