WO2023016561A1 - Catalyst system for cationic polymerization of c4 liquefied petroleum gas and polybutylene production method - Google Patents

Abstract

The present invention provides a catalyst system for cationic polymerization of C4 liquefied petroleum gas and a polybutene production method. Specifically, the catalyst system consists of the following components: an aluminum-containing Lewis acid catalyst, a nitrogen-containing Lewis base modifier, and an alkyl alcohol initiator. The present invention also provides a method for producing polybutylene by using liquefied petroleum gas as a raw material. The method has fewer processes, low requirements on raw materials, low production cost, and wide application field of products.

Description

Catalyst system for cationic polymerization of C4 liquefied petroleum gas and polybutene production method technical field

The present invention relates to a kind of production method of polyisobutylene. Specifically, the present invention relates to the production, separation method and product application of polyisobutylene products with different viscosities.

Background technique

Polyisobutene is obtained by selective cationic catalytic polymerization of pure isobutene or C4 hydrocarbon mixture containing isobutene, butadiene, n-butene, butane, etc. These polyisobutylenes are colorless, odorless, non-toxic, viscous and sticky substances, so they can be widely used as adhesives, lubricating oil thickeners, insulating oils, sealants, caulking agents, plasticizers, asphalt modifiers Agents and dispersants, especially for lubricating oils and lubricating oil additives.

It is well known that polybutene can be synthesized by polymerizing C4 hydrocarbons using a Friedel-Craft catalyst in the temperature range -20°C to 50°C and then separating the residual catalyst from the product. Preparation, said C4 hydrocarbons are produced from different feedstocks, such as feedstock from heavy oil catalytic cracking in petroleum refining, or from C4 hydrocarbon mixtures in naphtha cracking with or without 1 , 3-butadiene extracted raw materials. Depending on the feedstock composition and catalyst selectivity, the composition of polybutene will vary. Using pure isobutene or using a catalyst with high monomer selectivity to polymerize mixed butenes can obtain isobutene polymerization products; while using a catalyst with poor monomer selectivity to polymerize mixed butenes, in addition to isobutene polymers, there are butene-1, The product of butene-2 polymerized alone and the product of copolymerization of several monomers, these components have large differences in molecular weight and molecular weight distribution, so it will affect the properties and performance of the product.

In addition, due to the presence of a small amount of water in the solvent and the reaction raw materials, it can react with the Lewis acid catalyst to form a halogenated acid. The halogenated acid in the polymerization system will affect the structure of the polymerization product and the initiation efficiency of the catalyst. In the subsequent solvent and unreacted raw material recovery process, the halogenated acid must be removed so that the polymerization reaction can proceed smoothly.

In the patent method of polybutene disclosed in patent CN95104746, the content of butadiene in raw C4 hydrocarbons is limited to inhibit the polymerization of butadiene.

In the polybutene method disclosed in patent CN104053685, the raw material is required to maintain a relatively high isobutene content and a low butadiene content, and the polymerization reaction in which non-isobutene participates is suppressed by controlling the reaction process.

Traditional methods for removing catalysts left in the product after polymerization is complete include physical methods such as deposition, filtration, and adsorption, and chemical methods using water, ammonia, and alkaline solutions such as ammonia/sodium hydroxide and potassium hydroxide. Patent CN201480043574 discloses a method for recycling and reusing raw materials in a continuous polymerization system. This method uses alkaline substances such as oxides and hydroxides of alkali metals or alkaline earth metals to absorb and recover halogenated acids in raw materials and solvents.

Therefore, there is still a need for a polybutene production method that has a simple production process, is suitable for industrial production, and can overcome the problems existing in the production process of polybutene in the prior art.

Contents of the invention

The invention provides a polybutene production method which has simple production process, is suitable for industrial production, and can overcome the problems existing in the production process of polybutene in the prior art.

The first aspect of the present invention provides a catalyst system for cationic polymerization of C4 liquefied petroleum gas, characterized in that, the catalyst system consists of the following components:

Aluminum-containing Lewis acid catalysts;

Nitrogen-containing Lewis base modifiers; and

Alkyl Alcohol Initiation Auxiliary.

In another preferred embodiment, the molar ratio of the Lewis acid catalyst to the Lewis base modifier is 1:0.9 to 1:1.5; and/or

The molar ratio of the Lewis acid catalyst to the alkyl alcohol initiation aid is selected from 1:1 to 1:10.

In another preferred embodiment, the aluminum-containing Lewis acid catalyst is selected from the group consisting of aluminum chloride, alkyl aluminum dichloride (such as methyl aluminum dichloride, ethyl aluminum dichloride), or combinations thereof.

In another preferred example, the nitrogen-containing Lewis base modifier is an organic amine; preferably, the molecular formula of the organic amine is R ₁ (R ₂ )NR ₃ , wherein R ₁ is selected from C _6-16 A hydrocarbon group, R ₂ and R ₃ are each independently a C _3-7 hydrocarbon group, and the R ₂ and R ₃ are the same or different.

In another preferred example, the nitrogen-containing Lewis base modifier is selected from the group consisting of n-heptyl diisopropylamine, n-octyl diisopropylamine, n-nonyl diisopropylamine, n-decyl diisopropylamine, n-heptyldipropylamine, n-octyldipropylamine, n-nonyldipropylamine, n-decyldipropylamine, n-heptyldibutylamine, n-octyldibutylamine, tricyclohexylamine, dicyclohexylisopropylamine .

In another preferred example, the alkyl alcohol initiation aid is a C _1-7 alkyl alcohol compound.

In another preferred embodiment, the alkyl alcohol initiation aid is selected from the group consisting of tert-butanol, isopropanol, ethanol, or combinations thereof.

In another preferred embodiment, the alkyl alcohol initiation aid can be combined with a Lewis acid catalyst to generate carbocations, thereby initiating cationic polymerization.

A second aspect of the present invention provides a C4 liquefied petroleum gas catalytic polymerization method, said method comprising the following steps:

(a) adding liquefied petroleum gas and the catalyst system described in the first aspect of the present invention into the reactor and polymerizing to obtain a polymer feed liquid;

(b) fully adsorbing the polymerization feed liquid obtained in the step (a) with a powdery neutral or slightly alkaline porous substance, thereby adsorbing and separating the catalyst in the polymerization feed liquid;

(c) under reduced pressure, remove unreacted liquefied petroleum gas in the reaction feed liquid;

(d) in the presence of a hydrogenation catalyst, hydrogenate the reaction feed liquid from which the unreacted liquefied petroleum gas has been removed in step (c), to obtain a hydrogenation polymerization product;

and (e) rectifying the hydropolymerized product obtained in step (d) to obtain a high-viscosity polymer fraction, a medium-viscosity polymer fraction and a low-viscosity polymer fraction.

In another preferred example, the reaction temperature of the step (a) is -20°C-70°C.

In another preferred example, the reaction pressure of the step (a) is 1-10 bar.

In another preferred example, the reaction time of the step (a) is 0.2-4 hours.

In another preferred example, the liquefied petroleum gas is petroleum gas containing C4 olefins produced in the petroleum refining process, wherein the isobutene content is 5-100% (mole); preferably, the liquefied petroleum gas is , the content of isobutene is 5-100% (mol), the content of butene-1 is 2-70% (mol), the content of butene-2 is 2-70% (mol), and the content of 1,3-butadiene is 0 ~50% (mol).

In another preferred example, the liquefied petroleum gas also contains a small amount of C3, C5 hydrocarbons (including olefins and alkanes).

In another preferred example, in the step (a), the polymerization reaction is carried out in a solvent, or in liquefied petroleum gas.

In another preferred embodiment, the solvent is an alkane organic solvent that is inert to the reaction raw materials and the catalyst.

In another preferred example, the solvent is selected from the group consisting of n-pentane, n-hexane, cyclohexane, n-heptane, methylcyclohexane, petroleum ether (30-60), petroleum ether (60-90 ), or a combination thereof, or a combination thereof.

In another preferred embodiment, when the polymerization reaction is carried out in a solvent, the solvent is removed from the reaction system and the product in the flashing stage and fractional distillation stage.

In another preferred example, in the step (b), the powdery neutral or slightly alkaline porous substance is selected from the group consisting of silica gel, alumina, diatomaceous earth powder, or combinations thereof.

In another preferred example, the powder particle size of the powdery neutral or slightly basic porous substance is 5-100 microns. The mass ratio of the porous substance to the catalyst is 0.02-20:1, preferably 0.2-10:1.

In another preferred example, in the step (d), the hydrogenation catalyst is a solid supported hydrogenation catalyst.

In another preferred example, in the step (d), the hydrogenation is carried out at a pressure of 0.5-10 MPa.

In another preferred example, in the step (d), the hydrogenation is carried out at a temperature of 50-200°C.

In another preferred example, in the step (d), the volume ratio of the hydrogenated hydrogen gas to the raw oil solution is 100-400:1.

In another preferred example, in the step (d), the space velocity of the hydrogenated hydrogen is 0.5-3h ^-1 .

In another preferred example, in the step (e), the rectification temperature is 150-280°C.

In another preferred example, in the step (e), the rectification absolute pressure is: 1-700Pa.

In another preferred example, the kinematic viscosity of the high-viscosity polymer fraction at 100°C is >100 mm ² /s, the acid value is less than 0.01 mg KOH/g, the pour point is lower than -15°C, and the viscosity index is higher than 110 .

In another preferred embodiment, the high-viscosity polymer fraction is used as lubricating oil base oil.

In another preferred example, the kinematic viscosity of the medium-viscosity polymer fraction at 100°C is 10-100

mm ² /s, the acid value is less than 0.01mg KOH/g, and the pour point is lower than -15°C.

In another preferred example, the medium-viscosity polymer fraction is used as oil for metal processing.

In another preferred example, the kinematic viscosity of the low-viscosity fraction at 100°C is 1-10 mm ² /s, the acid value is less than 0.01 mg KOH/g, and the pour point is lower than -25°C.

In another preferred example, the low-viscosity fraction is used as oil for metal processing.

The third aspect of the present invention provides an isobutylene polymer produced by the method as described in the second aspect of the present invention.

It should be understood that within the scope of the present invention, the above-mentioned technical features of the present invention and the technical features specifically described in the following (such as embodiments) can be combined with each other to form new or preferred technical solutions. Due to space limitations, we will not repeat them here.

Detailed ways

Based on long-term and in-depth research, the inventors of the present invention have found that the use of organic amines as performance modifiers for Lewis acids can change the catalyst's monomer selectivity to isobutene and butene-1, butene-2 and butadiene, etc. , reduce or even eliminate the occurrence of side reactions such as butene-1, butene-2 and butadiene polymerization, and inhibit and absorb the halogenated acid generated by the reaction system, thereby reducing the reaction process and reducing the requirements for raw materials in the polymerization reaction, thereby reduce manufacturing cost. In this study, by comparing the changes of liquefied gas components before and after polymerization, it was determined that only isobutylene participated in the polymerization during the polymerization process. The improvement of monomer selectivity is through the addition of organic amines in the Lewis acid catalyst system, which changes the acidity and alkalinity of the catalytic system/steric hindrance of catalytic intermediates, and finally changes the monomer selectivity of the catalytic system.

In addition, the present inventors also found that the use of powdery porous materials can simplify the catalyst removal process and reduce the output of waste water and the like.

Based on the above findings, the inventors have accomplished the present invention.

Petroleum liquefied gas

According to the present invention, the term "petroleum liquefied gas" uses the common concept in this field, that is, petroleum gas containing C4 olefins produced in the process of petroleum refining. In addition to isobutene, these C4 petroleum liquefied gases usually contain a large amount of 1-butene and 2-butene, and to a lesser extent 1,3-butadiene; moreover, there are usually significant proportions of butane and isobutane. These C4 petroleum liquefied gases comprising isobutene are, for example, C4 raffinates, such as "raffinate 2", and especially "raffinate 1"; C4 fragments originating from the dehydrogenation of isobutane; C4 fragments from steam cracking and FCC cracking (fluid catalytic cracking), etc. The petroleum liquefied gas described in the present invention can also be the product after certain component separation, enrichment and isomerization of the liquefied gas from the above petroleum refining process, wherein the component content of various C4 olefins is relative to the industrial source The petroleum liquefied gas has certain changes. Generally speaking, the component content scope of each C4 olefin of petroleum liquefied gas required by the present invention is: isobutene content is 5-50% (mol), butene-1 content is 2-70% (mol), butene-2 The content is 2-70% (mole), the content of 1,3-butadiene is 0-50% (mole), and the rest is C3, C5 hydrocarbons (including olefin and alkane components). Preferably the isobutene content is 5-30 mol %, the butene-1 content is 5-50 mol %, the butene-2 content is 5-30 mol %, the 1,3-butadiene content is 2 - 20% (mole) C4 hydrocarbon composition.

Catalyst system for initiating cationic polymerization of C4 liquefied petroleum gas

The invention relates to a catalyst system for initiating cationic polymerization of C4 liquefied petroleum gas. The catalyst system is composed of an aluminum-containing Lewis acid catalyst, a nitrogen-containing Lewis base modifier and an alkyl alcohol initiation aid .

Wherein, the catalyst is an aluminum-containing Lewis acid catalyst capable of initiating cationic polymerization of olefins. The aluminum-containing Lewis acid catalyst of the present invention is selected from aluminum chloride and alkylaluminum dichloride, preferably from aluminum chloride and ethylaluminum dichloride.

The nitrogen-containing Lewis base modifier of the present invention is an organic amine with the molecular formula R ₁ (R ₂ )NR ₃ , wherein R ₁ is selected from C _6-16 hydrocarbon groups, and R ₂ and R ₃ are each independently C _{3- 7} , and said R ₂ and R ₃ are the same or different.

In a preferred embodiment, the organic amine is preferably an organic amine selected from the group consisting of n-heptyldipropylamine, n-octyldipropylamine, n-heptyldiisopropylamine, n-octyldiisopropylamine, n-heptyldi Butylamine, n-octyldibutylamine, n-octyldipentylamine, n-nonyldihexylamine, triheptylamine, n-decyldiisopropylamine, n-undecyldiisobutylamine, n-dodecyl Dipropylamine, triphenylamine, tribenzylamine, tricyclohexylamine, dicyclohexylpropylamine, dicyclohexylisopropylamine, dicyclohexylisobutylamine and phenyldiisopropylamine, etc., More preferably selected from n-heptyldiisopropylamine, n-octyldiisopropylamine, n-heptyldibutylamine, n-octyldibutylamine, n-octyldipentylamine, n-nonyldihexylamine, triheptylamine, triheptylamine, Cyclohexylamine, dicyclohexylpropylamine, dicyclohexylisopropylamine and dicyclohexylisobutylamine, most preferably selected from n-heptyldiisopropylamine, n-octyldiisopropylamine, tricyclohexylamine and dicyclohexylamine Cyclohexylisopropylamine.

The amount of the organic amine is not limited. In a preferred embodiment, the ratio of the aluminum-containing Lewis acid catalyst to the organic amine is preferably from a molar ratio of 1:0.9 to 1:1.5, more preferably from 1:0.95 to 1 : a molar ratio of 1.2.

The catalyst system of the present invention also includes an auxiliary compound alkyl alcohol used in conjunction with the above catalyst to generate carbocations to initiate polymerization. The alkyl alcohol is preferably selected from methanol, ethanol, propanol, butanol, isopropanol, isobutanol and tert-butanol. In a preferred embodiment of the present invention, the alkyl alcohol is selected from isopropanol and tert-butanol.

The amount of the alkyl alcohol is not limited. In a preferred embodiment, the ratio of the aluminum-containing Lewis acid catalyst to the alkyl alcohol is selected from a molar ratio of 1:1 to 1:10, preferably from 1:1.1 to The molar ratio of 1:5 is more preferably selected from the molar ratio of 1:1.2 to 1:3.

Isobutylene Catalytic Polymerization Process

The present invention also relates to a preparation method for producing polyisobutylene using the above-mentioned catalyst system, specifically, the method comprises the following steps:

(a) adding liquefied petroleum gas, solvent and catalyst into the reactor, and polymerizing at a temperature range of -20°C-70°C, a pressure range of 1-10bar, and within 0.2-4 hours;

(b) a step of fully adsorbing the catalyst in the reaction solution of step (a) with a powdery neutral or slightly alkaline porous substance;

(c) a step of removing unreacted liquefied petroleum gas under reduced pressure;

(d) a step of hydrogenating the remaining liquid in the above step (c) through a hydrogenation catalyst;

and, (e) a step of fractionating the polymer obtained above to obtain lubricating oil base oil and metal working oil.

The reactor suitable for the present invention can be a tank reactor with an agitator, or a tubular reactor, can be a single reactor, or can be a combination of multiple reactors, and there is no special limitation at this . The polymerization reaction is generally carried out at a temperature ranging from -20°C to 70°C. The reaction is generally carried out at a constant temperature. It is also possible to choose to react at one temperature for a period of time, and then change the temperature to another temperature for a period of time. The polymerization reaction is generally carried out within a pressure range of 1-10 bar. The reaction pressure may be the vapor pressure generated by the liquefied gas itself, or may be provided by an inert gas such as nitrogen as required by the process. The polymerization reaction time is generally 0.2-4 hours, preferably 0.3-1 hours. After the polymerization reaction is finished, enter the next process step.

Each reaction component described in the present invention can be fed separately at the same time, as the feed mode of continuous reactor; Also can adopt petroleum liquefied gas, catalyst, organic amine and alkyl alcohol to feed separately, carry out mixing in the reactor method; the catalyst, organic amine and alkyl alcohol can also be diluted with liquefied petroleum gas, and then enter the reactor for mixed reaction; the solvent can also be used to mix the required materials, and then enter the reaction gas for mixed reaction. This is not particularly limited.

In the present invention, a suitable liquefied petroleum gas is petroleum gas containing C4 olefins produced in the petroleum refining process. Usually, the isobutene content in this type of petroleum gas is 5-80% (mol), usually 10-50 % (mole). In some embodiments of the present invention, the isobutene content in the petroleum gas is 5-50% (mol), the butene-1 content is 2-70% (mol), and the butene-2 content is 2-70% (mole), the content of 1,3-butadiene is 0-50% (mole), and the rest is C3, C5 hydrocarbons (including olefins and alkane components); the preferred content of isobutene is 5-30% (mole), butadiene A C4 hydrocarbon composition with an ane-1 content of 5-50 mole percent, a butene-2 content of 5-30 mole percent, and a 1,3-butadiene content of 2-20 mole percent.

In the present invention, the polymerization reaction is carried out in a batch or continuous manner under isothermal conditions, and different reaction temperatures can be used as required. The reaction time can be adjusted as needed, preferably 0.3-1 hour, but there is no special requirement.

In a preferred embodiment of the present invention, the polymerization reaction can be carried out in a solvent, and the solvent is an alkane organic solvent that is inert to the reaction raw materials and the catalyst. Solvent can be removed from the reaction system and products in the flash stage and fractional distillation stage. The solvent is preferably selected from pentane, hexane, heptane and cyclohexane. At this time, the volume ratio of the C4 liquefied petroleum gas to the solvent is selected from 10:1 to 1:10, preferably from 5:1 to 1:5. The polymerization reaction can also be carried out under solvent-free conditions, at this time, the petroleum liquefied gas itself is used as the solvent for the reaction.

In the present invention, after the polymerization reaction is completed, the obtained feed liquid is contacted with a powdery neutral or slightly basic porous substance, so as to absorb the residual catalyst and complete the separation. The powdery neutral or slightly alkaline porous substance is preferably selected from powders of silica gel, alumina, and diatomaceous earth, and the particle size of the powder can be 5-100 microns. The mass ratio of the porous substance to the catalyst is 0.02-20:1, preferably 0.2-10:1.

The process of separating the powdery porous substance from the polymerization reaction solution after adsorbing the catalyst in the present invention can be carried out by means such as centrifugal separation, filtration separation, etc., and there is no special limitation here.

The step of removing unreacted liquefied petroleum gas adopts a process well known to those skilled in the art, such as a vacuum flash process, and there is no special limitation here.

The hydrogenation step in the present invention means that the hydrogenation reaction obtained in the polymerization process is carried out through a fixed bed or tank type hydrogenation reactor before hydrogenation, so as to obtain a hydrogenated base oil. The hydrogenation process can be carried out under suitable conditions. For example, in a preferred embodiment, at a pressure of 0.5-10 MPa and a temperature of 50-200° C., the volume ratio of hydrogen to raw oil solution is 100-400:1, Carry out under the condition that the space velocity is 0.5～3h ^-1 .

In a preferred embodiment, the fixed-bed hydrogenation process can be described as follows: hydrogenation temperature: 150-280°C; hydrogenation pressure: 0.5-10.0MPa; space velocity: 0.5-3.0h-1; hydrogen oil Ratio: 100～400:1.

In a preferred embodiment, the tank-type processing technology can be described as follows: hydrogenation temperature: 100-180° C.; hydrogenation pressure: 2.0-6.0 MPa.

In the hydrogenation process, the catalyst used for hydrogenation is a commonly used hydrogenation catalyst, preferably a supported hydrogenation catalyst used in petrochemical industry, such as DC series products, RIW series, supported Raney nickel catalyst, aluminum nickel alloy hydrogenation catalyst, Palladium carbon catalyst, etc., but not limited to these several hydrogenation catalysts listed.

The hydrogenation step in the present invention can be carried out in the presence of a solvent, and the solvent is selected from alkane organic solvents that are inert to the hydrogenation reaction. It is preferably an alkane solvent selected from C5-C10, more preferably hexane, heptane, cyclohexane and isooctane. Solvents can be removed from the product during the fractional distillation stage. Solvent At this time, the volume ratio of the polyisobutene is selected from 10:1 to 1:10, preferably from 5:1 to 1:5. The hydrogenation step can also be carried out under solvent-free conditions, in which case the polyisobutene itself serves as a solvent for the hydrogenation reaction.

The rectification step of the present invention is to rectify the hydrogenated polyisobutene prepared in the hydrogenation process through negative pressure rectification, so as to obtain polyisobutene products of different viscosity grades. The rectification can use a conventional rectification tower, molecular distillation equipment or any device that can realize liquid fractionation available on the market. The technical parameters of rectification are as follows: rectification temperature: 150-280°C; rectification absolute pressure: 1-700Pa.

In addition, in order to ensure product quality, chromaticity and process stability, and save costs, some auxiliary processes can also be added, such as solvent recovery process, product decolorization, filtration, etc. All of these auxiliary processes can be used or one or more of them can be used according to the needs; the auxiliary processes can be used in different process links according to the needs.

According to the process step of the present invention, the polyisobutylene product obtained by the rectification step can be applied in different fields according to the difference in viscosity, wherein:

The high viscosity fraction can be used as lubricating base oil, its kinematic viscosity at 100°C is >100mm2/s, the acid value is less than 0.01mg KOH/g, the pour point is lower than -15°C, and the viscosity index is higher than 110.

The medium-viscosity fraction is used as metal processing oil. Its kinematic viscosity at 100°C is 10-100mm2/s, acid value is less than 0.01mg KOH/g, pour point is lower than -15°C, and viscosity index is higher than 110.

The low-viscosity fraction is used as oil for metal processing. Its kinematic viscosity at 100°C is 1-10mm ² /s, its acid value is less than 0.01mg KOH/g, and its pour point is lower than -25°C.

The above-mentioned products can be used alone as the base oil of the final product such as lubricating oil and quenching oil, and can also be used as a blending component of the final product after blending components of different viscosities according to a certain ratio.

technical effect

(1) The production method of the present invention reduces the reaction process, improves the isobutylene monomer selectivity of the polymerization process, reduces the requirements of the polymerization reaction on raw materials, simplifies the catalyst removal process, reduces the production cost, and increases the product application field, It is more suitable for industrialized production. By adopting the catalyst system of the present invention, liquefied petroleum gas doped with a small amount of isobutene can be used for catalytic polymerization, while isobutene monomer is consumed, other monomers are kept from participating in the reaction so as to avoid generation of by-products.

(2) The lubricating oil base oil produced by the method provided by the invention has the characteristics of cleanliness, good oxidation stability and high viscosity index, and is suitable for blending lubricating oil products.

(3) The metal processing oil produced by the method provided by the invention has the characteristics of low halogen content and non-corrosion, and is suitable for the blending of this metal processing oil.

Below in conjunction with specific embodiment, further illustrate the present invention. It should be understood that these examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention. For the experimental methods without specific conditions indicated in the following examples, the conventional conditions or the conditions suggested by the manufacturer are usually followed. Percentages and parts are by weight unless otherwise indicated.

The following examples will be used to illustrate the present invention in further detail, but the present invention is not limited to these examples. In various embodiments, the components of material 1, material 2 and material 3 used are shown in the table below:

Table 1 Material composition of petroleum liquefied gas

serial number	components	Material 1	Material 2	Material 3
1	Propylene	0.03	0.1	0.03
2	propane	0.06	0	0.04
3	Butadiene	0.67	0	5.01
4	Isobutane	31.71	3.94	23.21
5	Isobutylene	22.64	48.13	25.44
6	Butene-1	9.72	27.61	10.89
7	trans-2-butene	14.30	8.86	14.35
8	n-butane	9.86	6.13	10.03
9	cis-2-butene	10.52	5.23	10.46
10	n-pentane	0.49	0	0.53
11	total	100	100	100

In the following examples, gas chromatography (GC) was used to test the carbon four components in the raw materials and products of the polymerization reaction to monitor the progress of the reaction. The GC test samples were taken respectively before the polymerization reaction (after the reaction materials were mixed), during the polymerization reaction and after the polymerization reaction. The solvent in the reaction system was used as a reference to calculate the content of each component in the reaction system. This calculates the conversion of the components before and after the polymerization process.

Example 1

Inject C4 liquefied gas material 1, n-hexane solvent, aluminum chloride, n-heptyldiisopropylamine, auxiliary compound tert-butanol into the kettle-type continuous polymerization reactor respectively, and the volume ratio of C4 liquefied gas material 1 to n-hexane solvent is 1:2, the molar ratio of n-heptyl diisopropylamine and aluminum chloride (AlCl ₃ ) is 1.1:1, the molar ratio of tert-butanol and aluminum chloride (AlCl ₃ ) is 3:1, aluminum chloride is in this way A content injection: making the content of aluminum chloride 3 parts by weight relative to 100 parts by weight of material 1 in the reactant. The reactor was maintained at 45 °C, the reactor was under a pressure of at least 3 kg/ ^cm2 to keep the reactants in a liquid state, and the average residence time was 30 minutes. After 180 minutes passed, the collected polymerization product was added to another reaction kettle, and a sample was taken for GC testing. The remaining reaction solution was added to the silica gel powder with an average particle size of 150 μm accounting for 5% of the total mass of the material, and the solid was filtered after stirring for 15 minutes. The remaining reaction liquid is flashed to remove unreacted C4 liquefied petroleum gas, and then pumped into a fixed-bed hydrogenation reactor. The reactor is filled with clover-type alumina loaded with 1wt% palladium catalyst. Hydrogenation temperature: 180°C; hydrogenation pressure: 3.0MPa ;Space velocity: 1.0h-1; Hydrogen-to-oil ratio: 150:1; After hydrogenation, the product undergoes negative pressure distillation, the absolute pressure of the system is 30Pa, the heating temperature is 200°C, and the fractions before and after 100°C are collected respectively. GC test results showed that isobutene was completely consumed, and the contents of the remaining components remained unchanged. The conversion rate of the C4 liquefied gas into the polymer product was calculated by weighing to be 22.0%. The mass percentage, viscosity and viscosity index of each fraction in the polymer product are shown in Table 2.

Example 2

Basically the same as Example 1, but with the following changes:

The liquefied petroleum gas uses material 2, the catalyst uses ethyl aluminum dichloride, the organic amine uses tricyclohexylamine, the auxiliary compound uses isopropanol, and the reaction temperature adopts -15°C. The powdery porous substance is alumina powder with an average particle size of 300 μm. GC test shows that isobutene is completely converted after polymerization, and the remaining components remain unchanged. The conversion rate of the C4 liquefied gas into the polymer product was calculated by weighing to be 46.2%. The mass percentage, viscosity and viscosity index of each fraction in the polymer product are shown in Table 2.

Example 3

Basically the same as Example 1, but with the following changes:

A tank-type batch reactor is used. Material 3 was used for the liquefied petroleum gas, dicyclohexylisopropylamine was used as the organic amine, and the reaction temperature was 65°C. GC test showed that isobutene was completely converted after polymerization, and the remaining components remained unchanged. The conversion rate of the C4 liquefied gas into the polymer product was calculated by weighing to be 24.7%. The mass percentage, viscosity and viscosity index of each fraction in the polymer product are shown in Table 2.

Example 4

Basically the same as Example 1, but with the following changes:

The catalyst is ethyl aluminum dichloride, the auxiliary compound is ethanol, the molar ratio of ethanol to ethyl aluminum dichloride is 1.5:1, relative to 100 parts by weight of material 1 in the reactant, the content of ethyl aluminum dichloride 0.2 parts by weight. The reaction temperature is 0° C., and the powdery porous substance is diatomite powder with an average particle size of 200 μm. The conversion rate of the C4 liquefied gas into the polymer product was calculated by weighing to be 21.1%. The mass percentage, viscosity and viscosity index of each fraction in the polymer product are shown in Table 2.

Example 5

Basically the same as Example 1, but with the following changes:

The reaction materials are C4 liquefied gas material 1, n-hexane solvent, aluminum chloride, auxiliary compound tert-butanol, the volume ratio of C4 liquefied gas material 1 and n-hexane solvent is 1:2, tert-butanol and aluminum chloride (AlCl ₃ ) The molar ratio is 3:1.

GC test results showed that isobutene was completely consumed, the conversion rate of butene-1 was 22%, the conversion rate of trans-2-butene was 57%, the conversion rate of cis-2-butene was 30%, and the content of other components remained unchanged. The conversion rate of the C4 liquefied gas into the polymer product was calculated by weighing to be 42.0%. The mass percentage, viscosity and viscosity index of each fraction in the polymer product are shown in Table 2. The results showed that the monomer selectivity of catalytic polymerization was low without adding nitrogen-containing Lewis base modifier, and side reactions such as butene-1, butene-2 and butadiene polymerization occurred.

Table 2, product fractionation test results

All documents mentioned in this application are incorporated by reference in this application as if each were individually incorporated by reference. In addition, it should be understood that after reading the above teaching content of the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of the present application.

Claims (10)

1. A catalyst system for cationic polymerization of C4 liquefied petroleum gas, characterized in that the catalyst system consists of the following components:

   Aluminum-containing Lewis acid catalysts;

   Nitrogen-containing Lewis base modifiers; and

   Alkyl Alcohol Initiation Auxiliary.
2. The catalyst system according to claim 1, wherein the molar ratio of the Lewis acid catalyst to the Lewis base modifier is 1:0.9 to 1:1.5; and/or

   The molar ratio of the Lewis acid catalyst to the alkyl alcohol initiation aid is selected from 1:1 to 1:10.
3. The catalyst system according to claim 1, wherein said aluminum-containing Lewis acid catalyst is selected from the group consisting of aluminum chloride, alkyl aluminum dichloride (such as methyl aluminum dichloride, ethyl dichloride aluminum), or combinations thereof.
4. The catalyst system according to claim 1, wherein the nitrogen-containing Lewis base modifier is an organic amine; preferably, the molecular formula of the organic amine is R ₁ (R ₂ )NR ₃ , wherein R ₁ Selected from C _6-16 hydrocarbon groups, R ₂ and R ₃ are each independently C _3-7 hydrocarbon groups, and the R ₂ and R ₃ are the same or different.
5. The catalyst system according to claim 1, wherein the alkyl alcohol initiation aid is a _C1-7 alkyl alcohol compound.
6. A C4 liquefied petroleum gas catalytic polymerization method is characterized in that it comprises the following steps:

   (a) add liquefied petroleum gas and the catalyst system described in claim 1 in the reactor and carry out polymerization, thereby obtain the polymer feed liquid;

   (b) fully adsorbing the polymerization feed liquid obtained in the step (a) with a powdery neutral or slightly alkaline porous substance, thereby adsorbing and separating the catalyst in the polymerization feed liquid;

   (c) under reduced pressure, remove unreacted liquefied petroleum gas in the reaction feed liquid;

   (d) in the presence of a hydrogenation catalyst, hydrogenate the reaction feed liquid from which the unreacted liquefied petroleum gas has been removed in step (c), to obtain a hydrogenation polymerization product;

   and (e) rectifying the hydropolymerized product obtained in step (d) to obtain a high-viscosity polymer fraction, a medium-viscosity polymer fraction and a low-viscosity polymer fraction.
7. The method according to claim 6, wherein the liquefied petroleum gas is petroleum gas containing C4 olefins produced in the petroleum refining process, wherein the isobutylene content is 5-100% (mole); preferably, the In the liquefied petroleum gas mentioned above, the content of isobutene is 5-100% (mol), the content of butene-1 is 2-70% (mol), the content of butene-2 is 2-70% (mol), 1,3- The butadiene content is 0-50% (mol).
8. The method according to claim 6, characterized in that, in the step (a), the polymerization reaction is carried out in a solvent, or in a liquefied petroleum gas body.
9. The method according to claim 6, wherein in the step (b), the powdery neutral or slightly alkaline porous substance is selected from the group consisting of silica gel, alumina, diatomaceous earth powder, or its combination;

   Preferably, in the step (d), the hydrogenation catalyst is a solid supported hydrogenation catalyst.
10. An isobutylene polymer, characterized in that the isobutylene polymer is produced by the method according to any one of claims 6-9.