CN-121991267-A - Low-molecular-weight high-activity polyisobutene and preparation method thereof

CN121991267ACN 121991267 ACN121991267 ACN 121991267ACN-121991267-A

Abstract

A low molecular weight high activity polyisobutene and a preparation method thereof belong to the field of high molecular compound preparation. The preparation method utilizes a simple initiator, a coinitiator and a third component system to prepare the polyisobutene with low molecular weight and high activity. The low molecular weight high activity polyisobutene with 90% of external olefin content can be obtained by using a simple and easily obtained initiator and Lewis acid with relatively weak corrosion to equipment as a co-initiator and regulating and controlling a three-component catalytic system and optimizing a process flow at a relatively high temperature (-30 ℃ to 0 ℃).

Inventors

WANG WANHUI
LIAN XIANGYANG
LU DONGMING
ZHANG HONG
BAO MING
ZHENG WEIWEN
ZHANG YANG
LI HAILONG
WANG YU

Assignees

大连理工大学
盘锦信汇新材料有限公司

Dates

Publication Date: 20260508
Application Date: 20260410

Claims (10)

1. A preparation method of low-molecular-weight high-activity polyisobutene is characterized by adopting an initiator, a co-initiator and a third component as a catalytic system, taking isobutene as a monomer and polymerizing to obtain the low-molecular-weight high-activity polyisobutene, wherein the initiator is selected from one or more of methyl benzoate, 2-benzyl isopropanol, 2-methylbenzyl alcohol, 3-methylbenzyl alcohol, 4-methylbenzyl alcohol, 1- (2-methylphenyl) ethanol, 1- (4-methylphenyl) ethanol, 1-phenyl-1-propanol, benzhydrol, 2-hydroxybenzyl alcohol, 4-methoxybenzyl alcohol, 1- (4-methoxyphenyl) ethanol, 2, 6-dimethylbenzyl alcohol, 4-tert-butylbenzyl alcohol, 2-phenyl-2-propanol, 2- (p-tolyl) propan-2-ol, 2- (4-methoxyphenyl) propan-2-ol and 2- (4-chlorophenyl) propan-2-ol; the co-initiator is one or more of trimethylaluminum, triethylaluminum, triisobutylaluminum, dimethylaluminum chloride, diethylaluminum chloride, diisobutylaluminum chloride, ethylaluminum dichloride and isobutylaluminum dichloride; The third component is selected from one or more of benzyl methyl ether, benzyl ethyl ether, benzyl phenyl ether, phenyl ethyl ether, dibenzyl ether, dichloro ethyl ether, dibromoethyl ether, m-bromoanisole, p-bromoanisole, 4-iodophenyl anisole, dioxane and N, N-dimethylaniline.
2. The preparation method of the low-molecular-weight high-activity polyisobutene according to claim 1, wherein the initiator is one or more selected from 2-phenylisopropanol, 1-phenyl-1-propanol, 4-methylbenzyl alcohol, 1-phenylethanol, 1- (2-methylphenyl) ethanol and 1- (4-methylphenyl) ethanol, the co-initiator is one or more selected from dichloroethylaluminum and chlorodiethylaluminum, and the third component is one or more selected from dichloroethylaluminum, dibromoethylaluminum, m-bromoanisole and p-bromoanisole.
3. The method for preparing the low molecular weight and high activity polyisobutene according to claim 1, comprising the following steps: s1, preparing materials: the polymerization reaction system is in an anhydrous oxygen-free inert gas environment, and the solvent after removing the water and the oxygen, the isobutene monomer after removing the water and the oxygen, the initiator, the co-initiator and the third component are all stored in the inert gas environment; S2, polymerization: One of two polymerization methods is selected: Adding an initiator into a low-temperature constant-temperature reactor, replacing the low-temperature constant-temperature reactor with an anhydrous and anaerobic inert gas environment, adding a third component, an organic solvent and an isobutene monomer, and uniformly stirring to obtain a polymerization system; the second method comprises the steps of replacing a low-temperature constant-temperature reactor in an anhydrous and anaerobic inert gas environment, carrying out reaction and complexation on a co-initiator and a third component, adding the initiator, stirring uniformly, taking out a catalytic system after stabilization, adding the catalytic system into a solution containing isobutene monomers to form a polymerization system for catalytic polymerization, and adding a terminator for termination after the polymerization is finished to obtain a polymerization product; s3, post-processing: And (3) washing the polymerization product with deionized water, removing unreacted isobutene monomers and organic solvents, and drying to obtain the low-molecular-weight high-activity polyisobutene.
4. The method for preparing low molecular weight and high activity polyisobutene according to claim 3, wherein in S1, the organic solvent is selected from one or more of n-hexane, tetrahydrofuran, chloromethane, dichloromethane, toluene, chloroethane, chloroethylene and propane.
5. The process for preparing polyisobutene having low molecular weight and high activity according to claim 3, wherein the inert gas is nitrogen or argon.
6. The method for preparing the low-molecular-weight high-activity polyisobutene according to claim 3, wherein the mass concentration of the isobutene monomer in a polymerization system is 5-50wt%, the molar ratio of the initiator to the co-initiator is (0.01-1): 1, the molar ratio of the third component to the co-initiator is (1.5-5): 1, the mass percentage of the co-initiator in the monomer is 0.02-10wt%, the reaction temperature is-30-0 ℃, and the polymerization time is 5-60 min.
7. The method for preparing the low-molecular-weight high-activity polyisobutene according to claim 3, wherein the adding mode of the co-initiator is that when the co-initiator is one, the adding speed is 0.5-2 mL/min, when the co-initiator is two or more, the two co-initiators are slowly added at intervals of 0-45min in sequence, and the adding speed is 0.5-2 mL/min.
8. The method for preparing the low-molecular-weight high-activity polyisobutene according to claim 3, wherein the terminator is one of water, absolute methanol, absolute ethanol or an ethanol/water mixed solution containing 1wt% of NaOH, wherein in the ethanol/water mixed solution, the ethanol is water=1:1 according to the volume ratio, and the consumption of the terminator accounts for 1-5% of the volume of the polymerization system.
9. The method for preparing the low-molecular-weight high-activity polyisobutene according to claim 3, wherein in the step S3, a reduced pressure evaporation method is selected as a method for removing unreacted isobutene monomers and organic solvents, and the drying process parameters are that the pressure is 0.1MPa, and the temperature is 40-80 ℃ and the drying is carried out until the weight is constant.
10. The low molecular weight high activity polyisobutene is characterized in that the yield is 62-99% by adopting the preparation method of any one of claims 1-9, the number average molecular weight range is 460-5300g/mol, the molecular weight distribution is 1.14-2.66, and the content of external olefins (exo) is as high as 50-90%.

Description

Low-molecular-weight high-activity polyisobutene and preparation method thereof Technical Field The invention belongs to the field of high molecular compound preparation, and particularly relates to low molecular weight high activity polyisobutene and a preparation method thereof. Background Polyisobutene (Polyisobutylene, PIB for short) is a linear saturated polyolefin polymer material synthesized by isobutylene monomer through cationic polymerization reaction, has unique chemical structure and performance characteristics, and has wide application value in the fields of industry, medicine, energy sources and the like. Polyisobutenes are classified, according to the molecular weight, into low-molecular-weight polyisobutenes, medium-molecular-weight polyisobutenes and high-molecular-weight polyisobutenes, the molecular weight (Mn) of from 500 to 5000 g/mol being defined generally as low-molecular-weight polyisobutenes. The high-activity polyisobutene (HR PIB) is a linear polyolefin polymer with high terminal double bond content, the terminal double bond content can reach more than 60 percent, and the high-activity polyisobutene can chemically react with various functional group monomers. The HR PIB has excellent chemical corrosion resistance and aging resistance as common PIB products, has outstanding low-temperature fluidity and thermal stability, and has good compatibility to organic solvents, oil products and other media at normal temperature. Is mainly applied to the application fields of ashless dispersant, emulsion explosive emulsifier, surfactant, cleaner, antirust agent and the like, in particular in the field of ashless dispersants. In recent years, with the increase of the amount of lubricating oil additives, the amount of high-activity polyisobutene tends to increase year by year. In the polymerization process of the high-activity polyisobutene, BF 3、TiCl4, alCl 3 and the like are usually used as co-initiators, but the isomerization of a reaction system is serious, and the content of external olefin is difficult to further increase. The prior commercial high-activity polyisobutene adopts the technology of BASF company, and adopts BF3 complex catalyst to synthesize HRPIB in CN00130281.7 and other patents. The reaction produces highly reactive polyisobutenes at relatively high temperatures. However, this kind of polymerization method requires a plurality of polymerization stages, and the process is complex, the purity of raw materials is strictly required, and boron trifluoride has strong toxicity and corrosiveness and is not easy to post-treat. The polymerization products of fluorine-containing impurities, when used in synthetic fuel additives or lubricating oil additives, and further applied to engines, can evolve HF causing corrosion damage to equipment. In recent years, environmental protection technical standards in the fields of lubricating oil and fuel additives are continuously improved, and novel synthesis processes of high-activity polyisobutene (HRPIB) are also continuously developed. The main preparation routes at present mainly comprise two types, namely, one type is based on active cationic polymerization, HRPIB is prepared by quenching a polymerization end group, common quenching reagents comprise Allyl Trimethylsilane (ATMS), steric base and sulfide and ether compounds, and the other type is based on a conventional cationic polymerization system, and a complex formed by metal halide and ether is used as a coinitiator for isobutene polymerization. The system takes AlCl 3/R2 O as a catalytic combination at the earliest, and subsequently develops FeCl 3/R2O、TiCl4 and other catalytic systems for HRPIB synthesis. In order to improve the solubility of AlCl 3 catalysts in nonpolar solvents, researchers have further developed a RAlCl 2/R2 O catalytic system, from which highly reactive polyisobutenes can be synthesized. The patent CN101955558A adopts FeCl 3/oxygen-containing or sulfur-containing organic compound co-initiation system to prepare high-activity polyisobutene, promotes the removal reaction of active center carbon cations beta-H and reduces the generation of tertiary chlorine end groups by introducing oxygen-containing or sulfur-containing organic compound complexing agent into a polymerization system, thereby directly preparing the high-activity polyisobutene with high content of terminal alpha-double bonds, but the high-activity polyisobutene prepared by the method has lower yield in the embodiment and wider molecular weight distribution. The patent CN103965381A adopts TiCl 4/organic compound additive co-initiation system to prepare high-activity polyisobutene, and introduces organic compound additives consisting of components A such as thiols, thioethers and the like and components B such as phenols, alcohols and the like into a polymerization system to reduce the acidity of counter ions and increase the nucleophilicity and steric hindrance of the counter ions, and efficiently a