Polymerization of Isobutylene by AlCl<sub>3</sub>/Ether Complexes in Nonpolar Solvent

Dimitrov, Philip; Emert, Jack; Faust, Rudolf

doi:10.1021/ma3003856

Cited by 66 publications

(133 citation statements)

References 14 publications

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“…The advantages of CumOH/AlCl 3 OBu 2 initiating system is the high reaction rate and the possibility to synthesize well‐defined PIBs with a cumyl group at the α‐end of polymer chain ( F n (Cum) = 75–90%) and an exo ‐olefin group at the ω‐end 23, 29. This approach opens an access to difunctional exo ‐olefin terminated PIB 30.…”

Section: Room Temperature Polymerization Of Ibmentioning

confidence: 99%

“…One significant drawback of the aforementioned initiating systems is the conducting of the polymerization in toxic chlorinated solvent. To replace CH 2 Cl 2 , the polymerization of IB with H 2 O/AlCl 3 OBu 2 initiating system was studied in different solvents (toluene, α,α,α‐trifluorotoluene, and n ‐hexane) 29, 31, 33. In toluene, the H 2 O/AlCl 3 OBu 2 initiating system afforded low‐molecular‐weight HR PIB ( M n = 1000−2100 g mol −1 ) with relatively narrow MWD ( M w / M n = 1.4−2.6) in a good yield (70−90% in 10 min) and even with a better functionality (90−94% of exo ‐olefin end groups) compared to CH 2 Cl 2 at T > 0 °C (Table 1).…”

Section: Room Temperature Polymerization Of Ibmentioning

confidence: 99%

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Cationic polymerization of isobutylene at room temperature

Kostjuk¹,

Yeong²,

Voit³

2012

J. Polym. Sci. A Polym. Chem.

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This review highlights recent approaches toward polyisobutylene (PIB) by an energy efficient room temperature cationic polymerization. Special focus is laid on our own work using modified Lewis acids and nitrile-ligated metal complexes associated with weakly coordinating anions. In both cases, suitable conditions have been found for efficient production of PIB characterized by medium to low molar masses and a high content of exo double bonds as end groups-the typical features of highly reactive PIB, an important commercial intermediate toward oil and gasoline additives. These and other approaches demonstrate that the cationic polymerization of isobutylene is still not fully explored, and new innovative catalyst systems can lead to surprising results of high commercial interest.

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Section: Room Temperature Polymerization Of Ibmentioning

confidence: 99%

Section: Room Temperature Polymerization Of Ibmentioning

confidence: 99%

Cationic polymerization of isobutylene at room temperature

Kostjuk¹,

Yeong²,

Voit³

2012

J. Polym. Sci. A Polym. Chem.

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“…12 Our recent reexamination of the polymerization of IB with the CumOH/AlCl 3 ·Bu 2 O initiator/co-initiator system in DCM/hexanes (80/20 v/v) at −40°C, previously reported by Kostjuk and co-workers, 9 revealed that CumOH is not an initiator in conjunction with AlCl 3 ·Bu 2 O and that the true initiator is adventitious water. 1 Similarly, in 100% hexanes at 0°C…”

Section: ■ Introductionmentioning

confidence: 99%

Polymerization of Isobutylene by GaCl₃ or FeCl₃/Ether Complexes in Nonpolar Solvents

et al. 2012

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The carbocationic polymerization of isobutylene (IB), co-initiated by GaCl 3 or FeCl 3 ·dialkyl ether 1:1 complexes has been investigated in hexanes in the −20 to 10°C temperature range. In contrast to AlCl 3 ·diisopropyl ether (AlCl 3 ·i-Pr 2 O) complexes, 1 GaCl 3 ·i-Pr 2 O and FeCl 3 ·i-Pr 2 O readily co-initiate polymerization with 2-chloro-2,4,4-trimethylpentane (TMPCl) or tert-butyl chloride (t-BuCl) in the presence or absence of proton trap. In the absence of proton trap, chain transfer to monomer readily proceeded, resulting in close to complete monomer conversion and up to 85% exo-olefinic end group content. Diisopropyl ether complexes gave the highest polymerization rates, while nonbranched alkyl ether complexes were completely inactive. A polymerization mechanism is proposed to involve ether-assisted proton elimination to yield PIB exo-olefin, and the abstracted proton can subsequently start a new polymer chain by protonation of IB. Alternatively PIB + may be deactivated by ion collapse to yield PIBCl, which can be reactivated by the Lewis acid. The reasons for the difference in behavior between the Ga and Fe catalysts and the Al-based catalysts are described. ■ INTRODUCTIONLow molecular weight (M n ∼ 500−5000 g/mol) olefin end functional PIB is a precursor to motor oil and fuel additives. Currently two major industrial methods are utilized to produce low molecular weight IB homo or copolymers with olefinic end groups. The "conventional" method uses a C4 mixture and AlCl 3 or EtAlCl 2 based catalyst systems, which provides polybutenes with high trisubstituted olefinic content. 2,3 The other method employs pure IB and uses BF 3 complexes with either alcohols or ethers as catalysts, yielding highly reactive PIB (HR PIB) with high exo-olefinic end-group content. 4 In contrast to the trisubstituted olefins of conventional polybutenes, PIB exo olefins readily react with maleic anhydride in a thermal ene reaction to produce PIB succinic anhydride and subsequently polyisobutenyl succinimide ashless dispersants. Since chlorination is not necessary for maleation of HR PIB, the final product does not contain any chlorine, making HR PIB more desirable than conventional polybutenes.In recent decades, several new methods for the synthesis of HR PIB have been reported. For example, PIBCl was selectively dehydrochlorinated by a bulky base, e.g., potassium tertbutoxide to yield HR PIB. 5 Storey et al. used living cationic polymerization of IB at −80°C to obtain living PIB, which was then end-quenched with sterically hindered bases 6 or sulfides. 7 Another method used to produce HR PIB, developed by Kuhn and co-workers, involves inorganic/organometallic catalysts with weakly coordinating anions in dichloromethane (DCM). 8 Recently, Kostjuk and Wu independently reported that at moderate temperatures AlCl 3 ·dibutyl ether 9 (AlCl 3 ·Bu 2 O) and AlCl 3 ·i-Pr 2 O 10 complexes in DCM or DCM/hexanes 80/20 (v/ v) mixtures give HR PIB with exo-olefinic end-groups in excess of 90%. Shortly thereafter, Wu and co-workers also rep...

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“…This was confirmed by the results of polymerization with water as the initiator in the presence or absence of impurities (Supporting Information Table S33–S36). In these experiments, water with EADC · CEE yields H + EADCOH − , which initiates the polymerization. By increasing the concentration of acetone, the polymerization rate decreases, and at [acetone] = [H 2 O] polymerization was absent.…”

Section: Resultsmentioning

confidence: 99%

“…The exo‐olefin terminated PIB is also referred to as “highly reactive” PIB (HR PIB), since it readily reacts with maleic anhydride in a thermal “ene” reaction to produce PIB succinic anhydride that can be converted to polyisobutenylsuccinimide, used as ashless dispersants. In the recent years, several research groups have reported on new catalyst systems for the synthesis of HR PIB . Some major drawbacks for the new HR PIB process systems include low process temperatures and/or use of polar chlorinated solvents that present serious limitations for industrial application .…”

Section: Introductionmentioning

confidence: 99%

Catalytic chain transfer polymerization of isobutylene: The role of nucleophilic impurities

Rajasekhar

Haldar

Emert

et al. 2017

J. Polym. Sci. Part A: Polym. Chem.

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Fast polymerization of isobutylene (IB) initiated by tert‐butyl chloride using ethylaluminum dichloride·bis(2‐chloroethyl) ether complex (T. Rajasekhar, J. Emert, R. Faust, Polym. Chem. 2017, 8, 2852) was drastically slowed down in the presence of impurities, such as propionic acid, acetone, methanol, and acetonitrile. The effect of impurities on the polymerization rate was neutralized by using two different approaches. First, addition of a small amount of iron trichloride (FeCl3) scavenged the impurity and formed an insoluble FeCl3··impurity complex in hexanes. The polymerization rate and exo‐olefin content were virtually identical to that obtained in the absence of impurities. Heterogeneous phase scavenger (FeCl3) exhibited better performance than homogenous phase scavengers. In the second approach, conducting the polymerization in wet hexanes, the fast polymerization of IB was retained in the presence of impurities with a slight decrease in exo‐olefin content. 1H NMR studies suggest that nucleophilic impurities are protonated in the presence of water, and thereby neutralized. Mechanistic studies suggest that the rate constant of activation (ka), rate constant of propagation (kp), and rate constant of β‐proton elimination (ktr) are not affected by the presence of impurities. To account for the retardation of polymerization in the presence of impurities, delay of proton transfer to monomer in the chain transfer step is proposed. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 3697–3704

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Polymerization of Isobutylene by AlCl₃/Ether Complexes in Nonpolar Solvent

Cited by 66 publications

References 14 publications

Cationic polymerization of isobutylene at room temperature

Cationic polymerization of isobutylene at room temperature

Polymerization of Isobutylene by GaCl₃ or FeCl₃/Ether Complexes in Nonpolar Solvents

Catalytic chain transfer polymerization of isobutylene: The role of nucleophilic impurities

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Polymerization of Isobutylene by AlCl3/Ether Complexes in Nonpolar Solvent

Cited by 66 publications

References 14 publications

Cationic polymerization of isobutylene at room temperature

Cationic polymerization of isobutylene at room temperature

Polymerization of Isobutylene by GaCl3 or FeCl3/Ether Complexes in Nonpolar Solvents

Catalytic chain transfer polymerization of isobutylene: The role of nucleophilic impurities

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Polymerization of Isobutylene by AlCl₃/Ether Complexes in Nonpolar Solvent

Polymerization of Isobutylene by GaCl₃ or FeCl₃/Ether Complexes in Nonpolar Solvents