Characteristics and Mechanism of Vinyl Ether Cationic Polymerization in Aqueous Media Initiated by Alcohol/B(C6F5)3/Et2O

Abstract

Aqueous cationic polymerizations of vinyl ethers (isobutyl vinyl ether (IBVE), 2-chloroethyl vinyl ether (CEVE), and n-butyl vinyl ether (n-BVE)) were performed for the first time by a CumOH/B(C6F5)3/Et2O initiating system in an air atmosphere. The polymerization proceeded in a reproducible manner through the careful design of experimental conditions (adding initiator, co-solvents, and surfactant or decreasing the reaction temperature), and the polymerization characteristics were systematically tested and compared in the suspension and emulsion. The significant difference with traditional cationic polymerization is that the polymerization rate in aqueous media using B(C6F5)3/Et2O as a co-initiator decreases when the temperature is lowered. The polymerization sites are located on the monomer/water surface. Density functional theory (DFT) was applied to investigate the competition between H2O and alcohol combined with B(C6F5)3 for providing a theoretical basis. The effectiveness of the proposed mechanism for the aqueous cationic polymerization of vinyl ethers using CumOH/B(C6F5)3/Et2O was confirmed.

Cationic Polymerization of β‐Pinene Using B(C6F5)3 as a Lewis Acid for the Synthesis of Tackifiers in Pressure Sensitive Adhesives

“…As a result, B(C 6 F 5 ) 3 has attracted interest for the cationic polymerization of a wide range of monomers including styrenics, [28][29][30][31][32] isoprene, [33,34] cyclopentadiene, [35,36] and vinyl ethers. [37] It has been shown for a number of monomer systems that when combined with alcohol initiators the reaction proceeds by reversible activation of the C─OH chain end [38] to give a propagating carbocation, thus allowing for some living character to the reaction and good control over the molecular weight. [28,29] In this article, we demonstrate the polymerization ofpinene at room temperature in dichloromethane (DCM) using tris(pentafluorophenyl)borane as catalyst.…”

Structures and Stability of Complexes of E(C6F5)3 (E = B, Al, Ga, In) with Acetonitrile

“…Despite of numerous examples of existing catalytic systems and continuous efforts to develop the new ones, catalysis with group 13 Lewis acids remains one of the most relevant and widely applicable both in laboratory practice and in industry. For example, B(C 6 F 5 ) 3 is used as initiator for vinyl ether cationic polymerization in aqueous media, and as a co‐catalyst in the Ziegler–Natta reaction . In past decade, B(C 6 F 5 ) 3 as a classic Lewis acid is utilized for the construction of the frustrated Lewis pairs (FLP) for the activation of small molecules .…”

Visible light‐catalyzed living cationic homopolymerization and copolymerization of isobutyl vinyl ether: Characteristics and mechanism

“…16 Up to now, research on vinyl ether polymerization mainly focuses on green polymerization methods, including aqueous polymerization, photopolymerization, electro-polymerization, and microflow polymerization. [17][18][19][20][21][22] Recently, great progress has also been made in the photo-polymerization of vinyl ethers. Yagic group successfully polymerized poly (vinyl ethers) with a narrow Đ by a method of visible light-initiated radical oxidation/addition/inactivation reaction.…”