CN109456433B - A kind of method for preparing high activity polyisobutylene in ionic liquid medium - Google Patents

Abstract

The invention discloses a method for preparing high-activity polyisobutylene in an ionic liquid medium, which belongs to the technical scope of polymer homopolymer synthesis. The method adopts ionic liquid as solvent, uses isobutylene as raw material, and prepares high-activity polyisobutylene through positive ion polymerization under different initiation systems and different feeding modes under the temperature condition of -7～-30°C; The number-average molecular weight of the active polyisobutene is 500-5000 g/mol, the molecular weight distribution is narrow, and the molecular weight distribution is 1.5-3.0; the conversion rate of isobutene is 50-100%; and the content range of the outer olefin terminal structure is 70-99 mol%. The preparation process of the invention is simple, the repeatability is good, the ionic liquid and the catalytic system can be recovered and recycled for practical use, and the production cost is reduced.

Description

A kind of method for preparing high activity polyisobutylene in ionic liquid medium

technical field

The invention belongs to the technical scope of polymer homopolymer synthesis, and particularly relates to a method for preparing high-activity polyisobutylene in an ionic liquid medium.

Background technique

Low molecular weight polyisobutene (PIB) (Mn = 500–5000 g/mol) is the most important industrial product among isobutene polymers, it is mainly used in the production of motor oil and fuel additives, accounting for 75–80% of the total polyisobutene market %. Currently, there are two types of low molecular weight polyisobutenes on the market: (i) conventional polyisobutenes and (ii) highly reactive polyisobutenes (HRPIB). Compared with conventional polyisobutene, the main use of highly reactive polyisobutene is to produce polyisobutene succinimide ashless dispersant by direct thermal addition (Mach H., Rath P., Lubrication Science, 1999, 11(2): 175). This ashless dispersant has a wide range of uses, the main uses are: fuel additives, fuel detergents, emulsifiers for the production of emulsion explosives, and scale inhibitors in petroleum refining and petrochemical processes. In addition, the derivatives of HR PIB can also be used as internal plasticizers and moisturizing and moisturizing of cosmetics.

Conventional high activity polyisobutene synthesis method (Exxon process) is based on AlCl3 or _EtAlCl2 co _- initiated C4 mixture polymerization. The "conventional" polyisobutene obtained in this way contains predominantly tri- and tetra-substituted olefin end groups, which are much less reactive compared to the exo olefin end groups. Therefore, HR PIBs need to be prepared by the chlorination-dehydrochlorination method of polyisobutylene; although the HR PIBs obtained by this method have a high α-olefin end group content (α-olefin ≥ 95%), the main The disadvantage is that the polymer has to be purified and the dehydrochlorination time is too long and tetrahydrofuran needs to be used as a solvent; ref "Kostjuk Sergei-V., RSC Adv., 2015, 5:13125"; in addition, this method leads to a large amount of The generation of chlorine-containing wastewater and the pollution of volatile organic solvents to the environment are environmentally unfriendly methods.

Commercially active polyisobutenes were synthesized using BASF's technology using BF ₃ and alcohol and/or ether as co-initiators at moderately high temperatures (-20 to -10°C) in organic hydrocarbon solvents. However, the main disadvantage of this technique is that BF ₃ is gaseous and therefore difficult to handle and harmful to equipment. Due to the impending changes in the technical standards of lubricating oil/fuel additives, coupled with the increasing demand for HR PIB in recent years, various research institutions and industrial companies are showing increasing interest in improving the synthesis method of HR PIB. Several new methods for synthesizing HR PIBs are emerging.

Some new HR PIB synthesis methods reported in recent years are reviewed in some foreign literatures. Including: One is a method based on end group quenching of active cationic polymerization to obtain HR PIB. Commonly used end-group quenching methods are: allyltrimethylsilane (ATMS)) end-group quenching, hindered base end-group quenching, and sulfide and ether end-group quenching methods; another method is based on conventional positive quenching. A method of ionic polymerization using conventional metal halide and ether complexes as co-initiators for the cationic polymerization of isobutene. Initially, AlCl ₃ /R ₂ O was used; then FeCl ₃ (GaCl ₃ )/R ₂ O was successively used for the synthesis of HR PIBs. In order to improve the solubility of AlCl ₃ catalysts in non-polar solvents, RAlCl ₂ /R ₂ O catalytic systems were produced successively.

The domestic synthetic method of HR PIB mainly uses BF ₃ and the complex of metal chloride and alcohol or ether as the catalytic system.

In CN00130281.7 and other patents, BF ₃ complex catalyst is used to synthesize HR PIB.

Patent CN200810115711.8 In the liquid-phase isobutene raw material polymerization system, AlCl ₃ and oxygen-containing organic compounds are used to form a complex catalyst to initiate the polymerization of isobutene. The content of terminal α-double bonds is generally increased to more than 80 mol%, and even more than 90 mol%.

Patent CN201310041415.9 proposes a method for preparing high-activity polyisobutene by co-initiating cationic polymerization of isobutene with _TiCl in the presence of alcohol, phenol and/or ether organic compounds, by adjusting the amount ratio of alcohol, phenol or ether and the space of counter ions Steric hindrance can directly obtain highly active polyisobutylene with a narrow molecular weight distribution (distribution index can reach 1.2), and the content of α-double bonds at the chain end can be as high as more than 90%.

Patent CN201110124655.6 adopts an initiation system composed of SnCl ₄ , water and oxygen-, nitrogen- and/or sulfur-containing organic compounds to synthesize HR PIB. up to 98%.

Patent CN200810115710.3 uses AlR _(3-n) Cl _n compound and phenols or piperidines, alkyl ethers as the catalytic system to initiate the polymerization of isobutene, and the obtained polyisobutene has a number-average molecular weight of 500-15000 Daltons, The optimum content of terminal α-double bonds is 96 mol%.

Patent CN200910089266.7 uses the complex of FeCl3 and oxygen _- containing or sulfur-containing organic compounds as the catalytic system to directly obtain high-activity polymer with terminal α-double bond content greater than 75mol% (can be as high as 90% or more) and narrow molecular weight distribution. isobutylene.

Although HR PIBs based on metal halide and ether complexes as catalytic systems have been rapidly developed, so far, the commercial synthesis methods of HR PIBs are still based on the BF ₃ complex catalytic system, and other methods have not been industrialized.

As a green solvent, ionic liquids are widely used in the fields of organic synthesis and catalysis, macromolecular synthesis, and oligomerization of isobutene. Patent WO 00/32658 reports the synthesis of high molecular weight polyisobutene (molecular weight up to 100,000) using [Emim]AlCl ₄ as an initiator or co-solvent, but the patent does not describe the structure of the polymer. In addition, the literature reported that [emim]Cl–AlCl ₃ and isopropyl ether complex were used as a new catalyst for the synthesis of HR PIB. Cationic polymerization of isobutene in a solvent yields HR PIB with a relatively narrow molecular weight distribution (M _w / _Mn ≤ 2.0) and a terminal α-double bond content ≥ 90%.

SUMMARY OF THE INVENTION

The object of the present invention is to propose a method for preparing high-activity polyisobutene in an ionic liquid medium. The high-activity polyisobutene was prepared by positive ion polymerization under the initiation system and different feeding methods; the number-average molecular weight of the obtained high-activity polyisobutene was 500-5000 g/mol, and the molecular weight distribution was 1.5-3.0; the conversion rate of isobutene was 50 -100%; the content of exo-olefin terminal structures is in the range of 70-99 mol%.

The initiating system is composed of a main initiator and a co-initiator; the concentration of the main initiator is 0.1-1×10 ^-4 mol/L, preferably 0.05-2×10 ^-3 mol/L; the co-initiator and the main initiator are Concentration ratio: 0.1-60; preferably 1-40.

The feeding method of the main initiator and the co-initiator as the initiation system is to use the main initiator and the co-initiator to feed separately, or to mix the main initiator and the co-initiator and then add them to the reactor; or to use the main initiator and the co-initiator to mix And added to the reactor after aging.

The initiating system is based on water as the main initiator, and the co-initiators are aluminum trichloride (AlCl ₃ ), ethyl aluminum dichloride (EtAlCl ₂ ), triethyl aluminum trichloride (Et ₃ Al ₂ Cl ₃ ) ), titanium tetrachloride (TiCl ₄ ), boron trifluoride (BF ₃ ), boron trichloride (BCl ₃ ), ferric chloride (FeCl ₃ ) and other co-initiators.

The monomer concentration of the isobutene is 0.5-8 mol/L, preferably 3-6 mol/L.

The cation of the ionic liquid is selected from imidazolium salt cation, pyridinium salt cation, quaternary ammonium salt cation and the like.

The imidazolium salt cations are selected from N,N'-dialkylimidazolium cations; the pyridinium salt cations are selected from alkylpyridine cations; the quaternary ammonium salt cations are selected from alkylpyrrole salt cations.

The anions of the ionic liquid are selected from anions that are stable to water and air, including: BF ₄ ^- , PF ₆ ^- , TA(CF ₃ COO ^- ), TfO ^- (CF ₃ SO ₃ ), NfO ^- (C ₄ F ₉ ) SO ₃ ^- ), Tf ₂ N ^- ((CF ₃ SO ₂ ) ₂ N ^- ), BeTi(C ₂ F ₅ SO ₂ ) ₂ N ^- ), Tf ₃ C ^- ((CF ₃ SO ₂ ) ₃ C ^- ) , SbF ₆ ^- , AsF ₆ ^- , EtSO ₄ ^- , MeSO ₄ ^- ; among which non-coordinating anions are preferred: BF ₄ ^- , PF ₆ ^- , TfO ^- , Tf ₂ N ^- and BeTi;

The described preparation of high-activity polyisobutene according to the different feeding modes of the initiation system includes:

Mode 1, adopts the mode that main initiator and co-initiator are respectively fed to prepare high-activity polyisobutene, including the following steps:

(1) Feeding of the reactor: under the condition of -7～-30℃, add 1-50mL of ionic liquid, initiator and co-initiator into the reactor, and each material needs to be mixed evenly;

(2) Polymer synthesis: under the condition of -7～-30℃, add 1-30mL of isobutene to the reactor, carry out the polymerization reaction under stirring, after the polymerization reaction for 10min-60min, add pre-cooled methanol to terminate the reaction, and simply decant The product was collected, washed with methanol for several times, and dried under vacuum to obtain highly reactive polyisobutene.

Mode 2 adopts the main initiator and the co-initiator to be mixed and then added to the reactor; or the main initiator and the co-initiator are mixed and aged and then added to the reactor to prepare high-activity polyisobutene, including the following steps:

(1) Initiator system configuration: fully mix co-initiator and initiator according to the ratio of co-initiator to initiator 1-40, and age at low temperature for 2-10 min;

(2) Feeding of the reactor: under the condition of -7～-30℃, add 1-50mL of ionic liquid and initiator system into the reactor, and mix evenly;

(3) Polymer synthesis: under the condition of -7～-30℃, add 1-30mL of isobutene to the reactor, carry out the polymerization reaction under stirring, after the polymerization reaction for 10min-60min, add pre-cooled methanol to terminate the reaction, and simply decant The product was collected, washed with methanol for several times, and dried under vacuum to obtain highly reactive polyisobutene.

The prepared high activity polyisobutylene is used for the preparation of lubricating oil and fuel additives, and for further functionalization of polyisobutylene to prepare telechelic polymers.

The beneficial effect of the present invention is that the present invention uses the ionic liquid as the solvent to provide an ionic environment for the positive ion polymerization of isobutene, promote the ionization of the initiation system, stabilize the carbocation active center, control the reaction rate, reduce the molecular weight distribution, and reduce the molecular weight. The distribution range is 1.5-3.0; the selectivity of the polymer product is improved, the stability of the initiation system in the ionic liquid is higher, the yield of the synthesized high-activity polyisobutylene is higher, and the conversion rate of isobutylene is 50-100%. The molecular weight of the polymerized product is 800-5000 g/mol, and the high-activity polyisobutylene synthesized by this method has a content of the external olefin end group structure in the range of 70-99 mol%.

Description of drawings

FIG. 1 is the ¹ H NMR spectrum of HR PIB of the synthesized product of Example 1. FIG.

Fig. 2 is the GPC curve of HR PIB of the synthetic product of Example 1.

FIG. 3 is the ¹ H NMR spectrum of HR PIB of the synthesized product of Example 3. FIG.

Fig. 4 is the GPC curve of HR PIB of the synthetic product of Example 3.

FIG. 5 is the ¹ H NMR spectrum of HR PIB of the synthesized product of Example 7. FIG.

FIG. 6 is the ¹ H NMR spectrum of HR PIB of the synthesized product of Example 9. FIG.

Detailed ways

The invention provides a method for preparing high-activity polyisobutene in an ionic liquid medium. The method adopts ionic liquid as a solvent, and uses isobutene as a raw material at a temperature of -7 to -30° C. Under different feeding methods, high-activity polyisobutene is prepared by positive ion polymerization; the number-average molecular weight of the obtained high-activity polyisobutene is 500-5000 g/mol, and the molecular weight distribution is 1.5-3.0; the conversion rate of isobutene is 50-100%; The content of the olefin terminal structure is in the range of 70-99 mol%.

The following examples are given to further illustrate the present invention, but the present invention is not limited to these examples, and the test methods are GPC and ¹ H NMR.

Example 1

Add 9mL [Bmim][PF ₆ ], 1.38mL CH ₂ Cl ₂ saturated aqueous solution, and 1.2mL 1mol/LTiCl ₄ solution to the reactor, add and mix, mix well, place in the cooling solution for 5min, at -10°C Under the conditions, 6 mL of isobutene was added to start the reaction. After 40 min of polymerization reaction, pre-cooled methanol was added to terminate the reaction. The product was collected by simple decantation, washed with methanol for several times, and dried in vacuum to obtain the final product. The ¹ H NMR spectrum of the HRPIB of the synthesized product is shown in FIG. 1 , and the GPC curve of the HRPIB of the synthesized product is shown in FIG. 2 .

Example 2

Add 15mL [Bmim][PF ₆ ], 0.55mL CH ₂ Cl ₂ saturated aqueous solution, and 1.9mL 1mol/LTiCl ₄ solution to the reactor, add and mix, mix evenly, and place in the cooling solution for 5min, at -10 Under the condition of °C, 10 mL of isobutene was added to start the reaction. After 40 min of polymerization, pre-cooled methanol was added to terminate the reaction. The product was collected by simple decantation, washed with methanol for many times, and dried in vacuum to obtain the final product.

Example 3

Add 24mL [Bmim][PF ₆ ], 0.88mL CH ₂ Cl ₂ saturated aqueous solution, and 1.04mL 1mol/LBCl ₃ solution to the reactor, add and mix, mix evenly, and place in the cooling solution for 5min, at -10 Under the condition of °C, 16 mL of isobutene was added to start the reaction. After 40 min of polymerization, pre-cooled methanol was added to terminate the reaction. The product was collected by simple decantation, washed with methanol for several times, and dried in vacuum to obtain the final product. The ¹ H NMR spectrum of the HR PIB of the synthesized product is shown in FIG. 3 , and the GPC curve of the HRPIB of the synthesized product is shown in FIG. 4 .

Example 4

Add 3mL [Bmim][PF ₆ ], 0.11mL CH ₂ Cl ₂ saturated aqueous solution, and 0.38mL 1mol/LBCl ₃ solution to the reactor, add and mix, mix well and place in the cooling solution for 5min, at -10 Under the condition of °C, 2 mL of isobutene was added to start the reaction. After 30 min of polymerization, pre-cooled methanol was added to terminate the reaction. The product was collected by simple decantation, washed with methanol for several times, and dried in vacuum to obtain the final product.

Example 5

Add 3mL [Bmim][BF ₄ ], 0.22mL CH ₂ Cl ₂ saturated aqueous solution, and 0.26mL 1mol/LTiCl ₄ solution to the reactor, add and mix, mix well and place in the cooling solution for 5min, at -10 Under the condition of °C, 2 mL of isobutene was added to start the reaction. After 40 min of polymerization, pre-cooled methanol was added to terminate the reaction. The product was collected by simple decantation, washed with methanol for many times, and dried in vacuum to obtain the final product.

Example 6

Add 9mL [Bmim][BF ₄ ], 1.02mL CH ₂ Cl ₂ saturated aqueous solution, and 1.74mL 1mol/LBCl ₃ solution to the reactor, add and mix, mix well and place in the cooling solution for 5min, at -20 Under the condition of ℃, 6 mL of isobutene was added to start the reaction. After 30 min of polymerization, pre-cooled methanol was added to terminate the reaction. The product was collected by simple decantation, washed with methanol for several times, and dried in vacuum to obtain the final product.

Example 7

Add 27mL [Bmim][BF ₄ ], 1.98mL CH ₂ Cl ₂ saturated aqueous solution, 2.34mL 1mol/LBF ₃ solution to the reactor, add and mix, mix well, place in the cooling solution for 5min, at -20 Under the condition of ℃, 18 mL of isobutene was added to start the reaction. After the polymerization reaction for 50 min, pre-cooled methanol was added to terminate the reaction. The product was collected by simple decantation, washed with methanol for many times, and vacuum-dried to obtain the final product. The ¹ H NMR spectrum of the HR PIB of the synthesized product is shown in FIG. 5 .

Example 8

Add 15mL [Bmim][Tf ₂ N], 3mL CH ₂ Cl ₂ saturated aqueous solution, and 1.8mL 1mol/L BF ₃ solution to the reactor, add and mix, mix well and place in the cooling solution for 5min, at - At 20°C, 10 mL of isobutene was added to start the reaction. After 40 min of polymerization, pre-cooled methanol was added to terminate the reaction. The product was collected by simple decantation, washed with methanol for several times, and dried in vacuum to obtain the final product.

Example 9

Add 3mL [Bmim][BF ₄ ], 0.22mL CH ₂ Cl ₂ saturated aqueous solution, 1.25mL 0.4mol/LEt ₃ Al ₃ Cl ₃ solution to the reactor, add and mix, mix well and place in the cooling liquid At -15°C for 5 min, 3 mL of isobutene was added to start the reaction. After 20 min of polymerization, pre-cooled methanol was added to terminate the reaction. The ¹ H NMR spectrum of the HR PIB of the synthesized product is shown in FIG. 6 .

Example 10

1.1mL of CH ₂ Cl ₂ saturated aqueous solution and 2.6mL of 0.4mol/L EtAlCl ₂ solution were mixed uniformly, placed in cooling liquid for 5min, and 30mL of [Bmim][PF ₆ ] was added to the reactor, and after uniform mixing Put it in the cooling solution for 5 minutes, and at -15°C, add 20 mL of isobutene to start the reaction. After 50 minutes of polymerization, add pre-cooled methanol to stop the reaction. Simply decant to collect the product, wash it with methanol for several times, and vacuum dry to obtain the final product.

Example 11

After mixing 0.11 mL of CH ₂ Cl ₂ saturated aqueous solution and 0.26 mL of 1 mol/L BF ₃ solution, place it in the cooling solution for 5 min, add 3 mL of [Bmim][Tf ₂ N] to the reactor, and mix it evenly. Put it in the cooling solution for 5 minutes, and at -15 °C, add 3 mL of isobutene to start the reaction. After the polymerization reaction for 20 minutes, add pre-cooled methanol to stop the reaction. The product is collected by simple decantation, washed with methanol for several times, and dried in vacuum to obtain the final product.

Example 12

After mixing 0.24mL of CH ₂ Cl ₂ saturated aqueous solution and 0.52mL of 1mol/L BCl ₃ solution, it was placed in the cooling solution for 5min, and 6mL of [Bmim][Tf ₂ N] was added to the reactor. Put it in the cooling solution for 5 minutes, and at -15 °C, add 6 mL of isobutene to start the reaction. After the polymerization reaction for 40 minutes, add pre-cooled methanol to stop the reaction. The product is collected by simple decantation, washed with methanol for many times, and dried in vacuum to obtain the final product.

The experimental data of each of the above-mentioned examples are collectively shown in Table 1.

Table 1 embodiment experimental data table

Claims (2)

1. a method for preparing high-activity polyisobutene in ionic liquid medium, it is characterized in that, adopting ionic liquid is solvent, under the temperature condition of-7～-20 ℃, with isobutene as raw material, in the concentration of main initiator It is 0.05～2×10 ^{- 3} mol/L; high activity polyisobutylene is prepared by positive ion polymerization under the initiation system with the concentration ratio of co-initiator and main initiator being 1～40 and different feeding methods; The number-average molecular weight of the obtained high-activity polyisobutene is 500-5000 g/mol, and the molecular weight distribution is 1.5-3.0; the conversion rate of isobutene is 50-100%; the content range of the outer olefin terminal structure is 70-99 mol%; The different feeding modes are selected from the following mode 1 or mode 2: Mode 1 adopts the mode of feeding main initiator and co-initiator respectively to prepare high-activity polyisobutene, including the following steps: (1) Feeding of the reactor: under the condition of -7～-20℃, add 1-50ml of ionic liquid, initiator and co-initiator to the reactor, and mix evenly for each material added; (2) Polymer synthesis: under the condition of -7～-20℃, add 1-30ml of isobutene to the reactor, carry out the polymerization reaction under stirring, after the polymerization reaction for 10min-60min, add pre-cooled methanol to terminate the reaction, and simply decant The product is collected and washed with methanol for many times, and dried in vacuum to obtain high-activity polyisobutene; Mode 2 adopts the main initiator and the co-initiator to be mixed and then added to the reactor; or the main initiator and the co-initiator are mixed and aged and then added to the reactor to prepare high-activity polyisobutene, including the following steps: (1) Initiator system configuration: fully mix co-initiator and initiator according to the ratio of co-initiator to initiator 1-40, and age at low temperature for 2-10 min; (2) Feeding of the reactor: under the condition of -7～-30℃, add 1-50ml of ionic liquid and initiator system to the reaction preparation, and mix evenly; (3) Polymer synthesis: under the condition of -7～-30℃, add 1-30ml of isobutene to the reactor, carry out the polymerization reaction under stirring, after the polymerization reaction for 10min-60min, add pre-cooled methanol to terminate the reaction, and simply decant The product is collected and washed with methanol for many times, and dried in vacuum to obtain high-activity polyisobutene; The initiating system is based on water as the main initiator, and the co-initiator is selected from one of EtAlCl ₂ , Et ₃ Al ₂ Cl ₃ , TiCl ₄ , BF ₃ , BCl ₃ and FeCl ₃ ; The cation of the ionic liquid is selected from N,N'-dialkylimidazolium cation; The anion of the ionic liquid is selected from: BF ₄ ⁻ , PF ₆ ⁻ , CF ₃ COO ⁻ , CF ₃ SO ₃ ⁻ , C ₄ F ₉ SO ₃ ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ , (C ₂ F ) ₅ SO ₂ ) ₂ N ^- , (CF ₃ SO ₂ ) ₃ C ^- , SbF ₆ ^- , AsF ₆ ^- , EtSO ₄ ^- , MeSO ₄ ^- ; The monomer concentration of the isobutene is selected from 3-6 mol/L. 2. method according to claim 1, is characterized in that, the cation of described ionic liquid is selected from 1-butyl-3-methylimidazolium cation; The anion of the ionic liquid is selected from: BF ₄ ⁻ , PF ₆ ⁻ , CF ₃ SO ₃ ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ .

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