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CN-121974789-A - Method for preparing cyclopentanone from cyclopentene

CN121974789ACN 121974789 ACN121974789 ACN 121974789ACN-121974789-A

Abstract

The invention provides a method for preparing cyclopentanone from cyclopentene, which belongs to the technical field of cyclopentanone production, wherein during esterification reaction, metal ions are removed through acetic acid to improve the activity stability of a sulfonic acid cation exchange resin catalyst, when transesterification reaction is carried out by using a reaction rectifying tower, the content of methyl acetate in the tower kettle is controlled below 0.01%, the transesterification reaction time is obviously shortened to enable the conversion rate to reach 100%, in the dealkalization process of a transesterification reaction liquid, a vertical falling film evaporator and a horizontal self-cleaning film evaporator which are connected in series can effectively separate organic matters from alkali and realize the continuity of the whole process of the transesterification reaction, and a proper CuO-ZnO/Al 2 O 3 high-activity dehydrogenation catalyst is selected to obviously improve the reaction efficiency, the energy consumption is obviously reduced, the single-pass conversion rate of the dehydrogenation reaction is more than 70%, and the selectivity of cyclopentanone is close to 100%.

Inventors

  • Fang Zheneng

Assignees

  • 铜陵贝斯美科技有限公司

Dates

Publication Date
20260505
Application Date
20260317

Claims (10)

  1. 1. A process for preparing cyclopentanone from cyclopentene, comprising the steps of: Step 1, acetic acid pretreatment, namely, passing fresh and/or recovered acetic acid through a first catalyst bed layer to remove metal ions, wherein the mass airspeed is 1-3 h -1 , the reaction temperature is 0-50 ℃, the reaction pressure is 0.0-normal pressure, the catalyst is sulfonic cation exchange resin, and the metal ion content of the acetic acid after treatment is less than or equal to 0.5ppm; step 2, esterification, namely mixing cyclopentene and acetic acid without metal ions, and then carrying out esterification reaction by passing a liquid phase through a second catalyst bed layer to obtain an esterification reaction liquid; Wherein the molar ratio of acetic acid to cyclopentene is 2-4:1, the mass space velocity is 1-3 h -1 , the reaction temperature is 40-70 ℃, the reaction pressure is 0.2-0.8 MPa, and the catalyst is sulfonic cation exchange resin; step 3, recovering cyclopentene, namely rectifying the esterification reaction liquid, collecting tower bottom liquid under normal pressure, recovering unreacted cyclopentene from the tower top, and recycling to the esterification process of the step 2; Step 4, acetic acid recovery, namely rectifying tower bottom liquid, recovering redundant acetic acid from the tower top under the condition of reduced pressure, and recycling to the esterification step 2 after the acetic acid pretreatment step of step 1 to obtain cyclopentylacetate from the tower bottom; Step 5, transesterification, namely pumping the mixed solution of the cyclopentylacetate, fresh methanol and sodium methoxide/methanol solution catalyst into a transesterification rectifying tower from a feeding port of the rectifying tower, pumping recovered methanol into the rectifying tower from a stripping section of the transesterification rectifying tower, and rapidly carrying out transesterification reaction on the cyclopentylacetate and the methanol under the catalysis of the sodium methoxide catalyst, wherein the content of methyl acetate in a tower kettle is controlled to be less than 0.01 percent; feeding tower kettle materials of the transesterification rectifying tower into a vertical falling film evaporator, and evaporating 80-90% of volatile methanol and cyclopentanol organic matters from the materials to form gas-phase materials; Step 6, methanol recovery, namely feeding the gas-phase material into a rectifying tower to recover methanol, and recycling the methanol to the transesterification process of the step 5 to obtain cyclopentanol from the tower kettle; And 7, dehydrogenating cyclopentanol through a CuO-ZnO/Al 2 O 3 fixed bed catalyst bed to prepare cyclopentanone, wherein the mass space velocity of the dehydrogenation reaction is 0.2-1.0 hr -1 , the system pressure is 0.0-0.5 bar, and the reaction temperature is 200-260 ℃.
  2. 2. The process for preparing cyclopentanone from cyclopentene according to claim 1, wherein in step 5, after the gas phase material has been distilled off, a slurry with a high solids content and flowability is fed into a horizontal self-cleaning thin film evaporator, the residual volatile substances are separated from the alkali and nonvolatile substances, and the separated solids are used as waste alkali or disposed of as hazardous waste.
  3. 3. The method for preparing cyclopentanone from cyclopentene according to claim 2, wherein the transesterification rectifying tower, the vertical falling film evaporator, and the horizontal self-cleaning thin film evaporator are sequentially connected in series.
  4. 4. The method for preparing cyclopentanone from cyclopentene according to claim 1, wherein in step 1, the mass space velocity is 1.5-2.5 h -1 , the reaction temperature is 25-40 ℃, and the reaction pressure is normal pressure.
  5. 5. The method for preparing cyclopentanone from cyclopentene according to claim 1, wherein in step 2, the molar ratio of acetic acid to cyclopentene is 2.5-3.5:1, the mass space velocity is 1.5-2.5 h -1 , the reaction temperature is 50-65 ℃, the reaction pressure is 0.3-0.5 MPa, and the mass exchange capacity of sulfonic cation exchange resin is 3.5-5.0 mmol/g.
  6. 6. The method for preparing cyclopentanone from cyclopentene according to claim 1, wherein the transesterification rectifying column of step 5 is a rectifying column having a theoretical plate number of 50, the feed inlet is located at 10 th theoretical plate of the rectifying column, and recovered methanol is pumped into the rectifying column from 40 th theoretical plate of the rectifying column.
  7. 7. The method for preparing cyclopentanone from cyclopentene according to claim 1, wherein in step 5, the mass ratio of methanol to cyclopentene acetate is 1.0-3.0:1, the mass ratio of sodium methoxide catalyst to cyclopentene acetate is 0.1-1:1, the temperature of a tower bottom is 60-80 ℃, the temperature of a tower top is 54-55 ℃, and the reflux ratio is 1-10:1.
  8. 8. The method for preparing cyclopentanone from cyclopentene according to claim 1, wherein in step 5, the evaporation temperature of the vertical falling film evaporator is 150-160 ℃, and the evaporation temperature of the horizontal self-cleaning thin film evaporator is 180-200 ℃.
  9. 9. The method for preparing cyclopentanone from cyclopentene according to claim 1, wherein in step 7, the mass space velocity is 0.3-0.8 hr -1 , the system pressure is 0.08-0.30 bar, and the reaction temperature is 230-250 ℃.
  10. 10. The method for preparing cyclopentanone from cyclopentene according to claim 1, wherein the CuO-ZnO/Al 2 O 3 catalyst of step 7 has a particle size ψ5×4.5 to 5.2mm.

Description

Method for preparing cyclopentanone from cyclopentene Technical Field The invention relates to the technical field of cyclopentanone production, in particular to a method for preparing cyclopentanone from cyclopentene. Background Cyclopentanone is an intermediate in the flavor and pharmaceutical industry, and can be used for producing novel flavor methyl dihydrojasmonate and brandone, and fine chemical products such as anxiolytic buspirone, and can also be used for synthesizing pesticides such as pesticides and herbicides. In addition, cyclopentanone has good solubility, and is widely used as a solvent in the electronic industry. The cyclopentene separated from the carbon five fraction of the ethylene byproduct produced by naphtha cracking can be used as a raw material to produce cyclopentanone, and the main process comprises two technical routes of a cyclopentene N 2 O direct oxidation method and a cyclopentene hydration-dehydrogenation method. Although the process for producing cyclopentanone by using the N 2 O direct oxidation method realizes industrialization, the process is limited to a specific region and can be matched with a byproduct N 2 O oxidant production device, so that the production cost of cyclopentanone can be greatly reduced. The cyclopentanol is prepared by hydration of cyclopentene, and the cyclopentanone is prepared by dehydrogenation, so that the method is an environment-friendly technical route and has great advantages in technical and economic aspects. Japanese patent JP2003212803 proposes a process for preparing cyclopentanol by hydration of cyclopentene with a strongly acidic cation exchange resin, which is described as having a single pass conversion of cyclopentene of about 3.50% and a selectivity of about 98% at a feed molar ratio of water to cyclopentene of 1.2-3.0. The Chinese patent application CN102399132A develops a method for preparing cyclopentanol from cyclopentene, which comprises the following steps of 1) carrying out an addition reaction on cyclopentene and acetic acid in a liquid phase through a fixed bed catalyst to generate cyclopentanol acetate, wherein the feeding molar ratio of cyclopentene to acetic acid is 1:2-5, the liquid mass space velocity is 1-3 h -1, the reaction temperature is 50-80 ℃, the reaction pressure is 0.2-0.7 MPaG, the catalyst is sulfonic cation exchange resin, the mass exchange capacity of the resin is 3-5.5 mmol/g, 2) carrying out rectification separation on the obtained addition reaction product to obtain refined cyclopentanol acetate, 3) carrying out an ester exchange reaction on the obtained refined cyclopentanol acetate and methanol in the liquid phase through the fixed bed catalyst to generate cyclopentanol acetate and methyl acetate, the feeding molar ratio of cyclopentene acetate to methanol is 1:2-5, the liquid mass space velocity is 0.8-2 h -1, the reaction temperature is 40-60 ℃, the reaction pressure is 0.1-0.5 MPaG, the cation exchange capacity of the catalyst is sulfonic cation exchange resin, and the rectification product is 3.5 mmol/g, and the byproduct is obtained by-4. The Chinese patent application CN102603486A proposes a method for preparing cyclopentanol from cyclopentene, which comprises the following steps of 1) mixing cyclopentene and acetic acid, carrying out esterification reaction on the mixture by a liquid phase through a catalyst bed layer to enable the cyclopentene and the acetic acid to be converted into cyclopentene acetate, wherein the molar ratio of the acetic acid to the cyclopentene is 2-5:1, the mass airspeed is 1-3 h -1, the reaction temperature is 50-80 ℃, the reaction pressure is 0.1-0.5 MPa, the catalyst is sulfonic cation exchange resin, 2) rectifying the reaction liquid in a rectifying tower with a theoretical plate number of 25, recycling unreacted cyclopentene and acetic acid from the top of the rectifying tower, recycling the unreacted cyclopentene and the acetic acid, and directly taking the crude cyclopentene acetate obtained from the tower kettle as transesterification reaction raw materials, 3) dehydrating methanol by using a 3A molecular sieve to enable the water content of the methanol to be reduced to be below 10ppm, 4) mixing the crude cyclopentene acetate and dehydrated methanol, carrying out transesterification reaction under the action of the catalyst CaO, the mass ratio of the cyclopentene acetate to the methyl acetate is 0.8:1-0.03, the mass ratio of the methyl acetate to the catalyst is 1-0.03 mm, and the mass ratio of the catalyst is 1-0.03 mm, and the reflux ratio of the catalyst is 1-0.0.03 mm, and the reflux ratio of the catalyst is directly fed into the rectifying tower from the rectifying tower is 1-0.0.0.0 mm, and the reflux ratio is calculated to be calculated and the mass of the catalyst is equal to 1-0.0 mm. The Chinese patent application CN102617290A describes a method for preparing cyclopentanol by mixing cyclopentene and acetic acid, then carrying out esterification reac