Acidic imidazole-based ionic liquids in the presence of diisopropyl ether as catalysts for the synthesis of highly reactive polyisobutylene: Effect of ionic liquid nature, catalyst aging, and sonication

Zinc-Mediated Living Cationic Polymerization

Here, we present a facile and robust method for living cationic polymerization using zinc wire as a catalyst precursor. Well-defined poly(vinyl ether)s with various molecular weights and narrow molecular weight distributions (Đ < 1.10) can be achieved at room temperature. Excellent living characteristics were observed in kinetic and chain extension experiments. Mechanistic investigations revealed that the polymerization was catalyzed by the in situ generation of trace zinc ions, which is the key to polymerization under mild conditions. The utilization of zinc wire offers several advantages, including reusability, easy separation and low metal residue. Furthermore, we extended the application of this method in continuous flow polymerization, opening up a promising avenue for scalable and efficient industrial production under mild conditions.

Polyisobutylenes with Controlled Molecular Weight and Chain-End Structure: Synthesis and Actual Applications

The polymerization of isobutylene allows us to obtain a wide spectrum of polyisobutylenes (PIBs) which differ in their molecular weight characteristics and the chemical structure of chain-end groups. The bulk of the PIBs manufactured worldwide are highly reactive polyisobutylenes (HRPIBs) with -C(Me)=CH2 end-groups and low-molecular weights (Mn < 5 kDa). HRPIBs are feedstocks that are in high demand in the manufacturing of additives for fuels and oils, adhesives, detergents, and other fine chemicals. In addition, HRPIBs and CMe2Cl-terminated PIBs are intensively studied with the aim of finding biomedical applications and for the purpose of developing new materials. Both chain control (molecular weight and dispersity) and chemoselectivity (formation of exo-olefinic or -CMe2Cl groups) should be achieved during polymerization. This review highlights the fundamental issues in the mechanisms of isobutylene polymerization and PIB analysis, examines actual catalytic approaches to PIBs, and describes recent studies on the functionalization and applications of HRPIBs and halogen-terminated PIBs.

Quasiliving carbocationic polymerization of isobutylene using FeCl3 as an efficient and water-tolerant Lewis acid: synthesis of well-defined telechelic polyisobutylenes

A cost-efficient approach for the preparation of well-defined low molecular weight difunctional polyisobutulenes possessing an exo-olefin or hydroxyl group was developed in this study.

Ultrafast and green ionic liquid-mediated controlled cationic polymerization towards amphiphilic diblock copolymers

IL-mediated ultrafast ambient temperature living cationic polymerization of styrene (St), yielding well-defined PSt and polystyrene-b-poly(isobutyl vinyl ether) diblock copolymers with acceptable dispersity values (Đ ≤ 1.21) is reported.

BF3 -Catalyzed Mukaiyama aldol reaction of acetaldehyde with 2-siloxy-1-propene

The Mukaiyama aldol reaction is a powerful tool for the construction of the carbon-carbon bond and the formation of β-hydroxycarbonyl compounds. In this work, the mechanism of acetaldehyde and 2-siloxy-1-propene both in the absence and presence of the catalyst BF₃ was investigated based on density functional theory. The mechanism includes two major steps: the formation of the carbon-carbon bond and the removal of SiH₃ /BF₂ by water. The energy barrier of the carbon-carbon bond formation process in the presence of BF₃ is obviously lower, indicating that BF₃ is a good catalyst for this reaction. In terms of molecular configuration, the different tensions between the five-membered-ring and six-membered-ring can be considered as the possible reason for the catalytic effect of BF₃ . In terms of charge transfer, the charges of natural population analysis in the carbon atom of the carbonyl group in acetaldehyde becomes more positive, which is easier to attack by nucleophiles and promote the nucleophilic process.

A Bibliometric Survey on Polyisobutylene Manufacture

Polyisobutylenes (PIB) constitute a versatile family of polymer materials that have been used mainly as fuel and lubricant additives. Particularly, the current commercial demand for highly reactive polyisobutylene (HR-PIB) products motivates the development of new processes and procedures to produce PIBs with high polymer yields, narrow molar mass distributions and high vinyl contents. For this reason, a bibliometric survey is presented here to map and discuss important technical aspects and technological trends in the field of solution cationic polymerization of isobutylenes. It is shown that investigations in this field are concentrated mainly on developed countries and that industrial initiatives indicate high commercial interest and significant investments in the field. It is also shown that use of catalyst systems based on AlCl3 and ether cocatalysts can be very beneficial for PIB and HR-PIB manufacture. Finally, it is shown that investigations search for cheaper and environmentally friendly catalysts and solvents that can be employed at moderate temperatures, particularly for the production of HR-PIB.

Recent advances in catalytic chain transfer polymerization of isobutylene: a review

This review presents the development of highly reactive polyisobutylene (HRPIB), a major commercial intermediate toward fuel and lubricant additives. Recent years have witnessed very substantial advances in the catalytic chain transfer polymerization (CCTP) of isobutylene/industrial Raffinate-1 (C4 Raffinate) to produce HRPIB, particularly in nonpolar solvents at elevated temperatures. The main subjects of this review are cationic polymerization of isobutylene, progress in HRPIB research and existing challenges, and recent advances of CCTP. New initiating/catalyst systems based on ionic liquids with Lewis acids are detailed, and this approach may open new views in the synthesis of HRPIB. Some current developments in CCTP of industrial Raffinate-1 and mechanistic studies are also described. This review strongly supports that the hydrocarbon soluble Lewis acid·ether (LA·ether) complex catalyzed CCTP will become the most popular technique for preparing HRPIB and could replace the traditional BF₃ catalyzed industrial method.

This review presents the development of highly reactive polyisobutylene (HRPIB), a major commercial intermediate toward fuel and lubricant additives.

Synthesis of highly reactive polyisobutylenesviacationic polymerization in ionic liquids: characteristics and mechanism

The cationic polymerization of isobutylene (IB) was systematically studied in a 1-butyl-3-methylimidazolium hexafluorophosphate ([Bmim][PF₆]) ionic liquid at −10 °C.

Alkoxy aluminum chlorides in the cationic polymerization of isobutylene: a co-initiator, carbocation stabilizer and chain-transfer agent

Alkoxy aluminum chlorides are efficient catalysts for the preparation of well-defined exo-olefin terminated PIBs of low (M_n ∼ 1000 g mol⁻¹) to medium (M_n up to 50 000 g mol⁻¹) molecular weight under mild experimental conditions.