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CN-122006766-A - Catalyst and method for synthesizing 4-methyl-1-pentene

CN122006766ACN 122006766 ACN122006766 ACN 122006766ACN-122006766-A

Abstract

The invention relates to the technical field of fine chemical engineering, in particular to a catalyst and a synthetic method of 4-methyl-1-pentene. The catalyst comprises 5-15 parts by weight of active components and 85-95 parts by weight of carrier, wherein the active components comprise an active component A and an active component B, the active component A is one or more selected from Li, na and K, the active component B is one or more selected from Cu, fe, co, ni, and the carrier is one or more selected from K 2 CO 3 microspheres, cs 2 CO 3 microspheres and CaCO 3 microspheres. The catalyst provided by the invention effectively solves the problem that the traditional metal complex catalyst cannot be recycled, breaks through the bottleneck of poor selectivity of the alkali metal catalyst and complex product distribution, and has the advantages of high propylene conversion rate, good selectivity of 4-methyl-1-pentene, less side reaction, simple product distribution, good stability and long service life.

Inventors

  • LIANG CHANGHAI
  • DONG KE
  • CHEN XIAO
  • LING YU
  • Niu Bingbo
  • CHEN PING

Assignees

  • 中国石油化工股份有限公司
  • 大连理工大学
  • 中石化宁波新材料研究院有限公司
  • 中国石油化工股份有限公司镇海炼化分公司

Dates

Publication Date
20260512
Application Date
20241111

Claims (10)

  1. 1. The catalyst is characterized by comprising 5-15 parts by weight of active components and 85-95 parts by weight of carriers, wherein the active components comprise an active component A and an active component B, the active component A is selected from one or more of Li, na and K, the active component B is selected from one or more of Cu, fe, co, ni, and the carriers are selected from one or more of K 2 CO 3 microspheres, cs 2 CO 3 microspheres and CaCO 3 microspheres.
  2. 2. The catalyst of claim 1, wherein the catalyst comprises 8-12 parts by weight of the active component and 88-92 parts by weight of the support.
  3. 3. Catalyst according to claim 1 or 2, wherein the mass ratio of active component a to active component B is 0.5-10:1, preferably 1.5-4:1.
  4. 4. The catalyst according to any one of claims 1 to 3, wherein the catalyst is prepared by dispersing an active component A and an active component B in a solvent to obtain an electroless deposition solution, and then adding a carrier to the electroless deposition solution to perform electroless deposition.
  5. 5. The catalyst according to claim 4, wherein the solvent is selected from one or more of dodecane, cyclopentane, hexadecane, preferably dodecane; preferably, the electroless deposition is carried out at a deposition temperature of 120-180 ℃, preferably 160-170 ℃, and a deposition time of 100-250min, preferably 160-200min.
  6. 6. A method for synthesizing 4-methyl-1-pentene, which is characterized by comprising the following steps: (1) Carrying out dimerization reaction on raw material liquid and a catalyst in a loop reactor to obtain a reaction product, wherein the raw material liquid comprises propylene and a reaction medium, and the catalyst is the catalyst according to any one of claims 1-5; (2) The reaction product is separated to obtain 4-methyl-1-pentene.
  7. 7. The synthetic method of claim 6, wherein the reaction medium is selected from one or more of cyclopentane, dodecane, hexadecane; preferably, the propylene content of the feed solution is 10-40wt%, preferably 15-25wt%; preferably, the mass ratio of the raw material liquid to the catalyst is 1:0.05-0.5, preferably 1:0.1-0.3.
  8. 8. The synthetic method according to claim 6 or 7, wherein the dimerization reaction has a reaction temperature of 155-185 ℃, preferably 165-175 ℃, a reaction pressure of 4-10MPa, preferably 6-8MPa, and a reaction residence time of 5-15h, preferably 8-12h.
  9. 9. The synthesis method according to any of claims 6-8, wherein the separation comprises the sub-steps of: 2-1, carrying out first separation on the reaction product to obtain a circulating catalyst and a reaction liquid; 2-2, fractionating the reaction liquid to obtain a light component and a heavy component, wherein the light component comprises a reaction medium and unreacted propylene; 2-3, rectifying the heavy component to obtain 4-methyl-1-pentene.
  10. 10. The synthesis process according to claim 9, wherein the recycled catalyst is returned to the loop reactor for recycling; preferably, the light fraction is returned to the loop reactor for recycling.

Description

Catalyst and method for synthesizing 4-methyl-1-pentene Technical Field The invention relates to the technical field of fine chemical engineering, in particular to a catalyst and a synthetic method of 4-methyl-1-pentene. Background 4-Methyl-1-pentene is an important branched alpha-olefin, and can be used as a comonomer to be copolymerized with ethylene to synthesize the linear low-density polyethylene with the advantages of high strength, high toughness, good tearing strength and the like. In addition, the density of the poly 4-methyl-1-pentene synthesized by taking the 4-methyl-1-pentene as a monomer is the lowest in all plastic materials, has good light transmittance and acid and alkali resistance, and is widely used in the medical and health industry. At present, 4-methyl-1-pentene is mainly synthesized by propylene dimerization, however, the propylene dimerization process is relatively complex, and a plurality of byproducts such as 1-hexene, 4-methyl-2-pentene, 3-hexene, C 9 and C 12 olefins and the like exist. In the early days, the french petroleum institute developed a propylene dimerization process that performed dimerization of liquid phase propylene using a homogeneous nickel complex as a catalyst, but the yield of 4-methyl-1-pentene was only 2%, and the catalyst could not be recovered and regenerated. The process realizes continuous production, but the content of 4-methyl-1-pentene in the produced product is 38.8wt%, the yield of 4-methyl-1-pentene is low, and the catalyst recovery is difficult. The UK petroleum company adopts a supported alkali metal catalytic system, takes Na/K 2CO3 as a catalyst, adopts a fixed bed reactor to carry out propylene dimerization to produce 4-methyl-1-pentene, and the reaction product can obtain the 4-methyl-1-pentene with the purity of 97.4 percent after five towers are separated. Although the reaction system can realize continuous production, the conversion rate of propylene is lower, the product composition is more complex, and the subsequent separation cost is increased. CN202110195908.2 discloses a synthesis method for preparing propylene dimerization catalyst in situ by using ammonia as solvent, the reaction system is carried out in an autoclave reactor, although the method couples the preparation process of the catalyst with the reaction process, the activity of the catalyst can be improved, the reaction is intermittent operation, the operation is complex, the product stability is poor, and large-scale application is difficult to realize. CN202111677275.5 discloses a method for synthesizing 4-methyl-1-pentene by propylene dimerization by fixed bed gas phase reaction, the adopted catalyst improves the surface microenvironment of the carrier, so that the carrier surface forms a special vacancy structure and is uniformly dispersed, the prepared catalyst has good performance, but alkali metal catalyst is easy to run off in the reaction process in the solid bed reactor, and the catalyst is deactivated. Therefore, it is needed to provide a catalyst and a process which can not only efficiently and continuously convert propylene, but also realize high selectivity to 4-methyl-1-pentene, and realize selective dimerization of propylene to prepare high added value 4-methyl-1-pentene fine chemicals, which are hot points and difficulties in current research. Disclosure of Invention The invention aims to solve the problems of short service cycle of a catalyst, low selectivity of 4-methyl-1-pentene, multiple side reactions, high product separation cost, difficulty in continuous production and the like in the process of synthesizing 4-methyl-1-pentene by propylene dimerization, and provides a catalyst and a synthetic method of 4-methyl-1-pentene. The first aspect of the invention provides a catalyst, wherein the catalyst comprises 5-15 parts by weight of active components and 85-95 parts by weight of carrier, wherein the active components comprise an active component A and an active component B, the active component A is selected from one or more of Li, na and K, the active component B is selected from one or more of Cu, fe, co, ni, and the carrier is selected from one or more of K 2CO3 microspheres, cs 2CO3 microspheres and CaCO 3 microspheres. In a second aspect, the invention provides a method for synthesizing 4-methyl-1-pentene, wherein the method comprises the following steps: (1) Carrying out dimerization reaction on raw material liquid and a catalyst in a loop reactor to obtain a reaction product, wherein the raw material liquid comprises propylene and a reaction medium, and the catalyst is the catalyst of the first aspect of the invention; (2) The reaction product is separated to obtain 4-methyl-1-pentene. Through the technical scheme, the beneficial technical effects obtained by the invention are as follows: 1) The catalyst provided by the invention effectively solves the problem that the traditional metal complex catalyst cannot be recycled, breaks through the bott