Phase-Transfer Polymerization of Methyl Methacrylate with Tetrabutylammonium Chloride–Na2S2O4-CCl4 in an Aqueous-Organic Two-Phase System

Abstract

ABSTRACT:The phase-transfer polymerization of methyl methacrylate with tetrabutylammonium chloride (TBACl)--Na 2S2 OcCCl4 initiator system was investigated in an aqueousorganic two-phase system. The initial rate of polymerization (Rp) was found to be proportional to the fed quantity of TBACI and square root of the fed quantity of Na2 S2O4 and CCl4 . A cyclic phase-transfer initiation mechanism has been proposed to account for the experimental data.KEY WORDS Phase-Transfer Polymerization / Methyl Methacrylate / Tetrabutylammonium Chloride/ Sodium Dithionite / Carbon Tetrachloride/ Many studies have been made on the phase-transfer-catalyzed reaction because of its preparative usefulness. A wide variety of reactions such as anionic displacement, alkylation, arylation, oxidation, reduction, and hydrolysis could be effectively accelerated by phase transfer catalysts. As for the applications of polymerization reactions, they have been successfully employed in condensation polymerization 1 and anionic polymerization. 2 Recently several authors reported the use of phase transfer catalysts for free-radical polymerizations of hydrophobic vinyl monomers in aqueous-organic two-phase. 3 In most cases, peroxydisulfate was used as a water-soluble initiator with a phase-transfer catalyst such as crown ethers or quaternary ammonium salts. During the course of our investigation on aqueous-organic two-phase polymerization 4 we found that the addition of tetrabutylammonium chloride (TBACl) as a phase-transfer catalyst to Na 2 S 2 0cCC1 4 initiator system induced radical polymerization of methyl methacrylate (MMA) under mild condition. On the basis of kinetic studies an initiation mechanism is suggested for the polymerization of MMA with TBACl-Na2 S20cCC14 in aqueous-organic two-phase system.

Photophysics of Perylene Diimide Dianions and Their Application in Photoredox Catalysis

“…In the biphasic mixtures, the organic phase is deep purple whilst the aqueous phase is comparatively weakly colored, signaling that the dianion form of PDI(H)–dipp remains hydrophobic despite its twofold negative charge (Figure 4 b). TBACl is essential to shuttle S 2 O 4 2− from the aqueous to the organic phase, and the role of the aqueous phase seems to be primarily that of a reservoir for dithionite [39] . Except for this key difference, it seems plausible that the photochemical mechanism in Figure 4 a also prevails for the lignin model compound photo‐degradations.…”

“…Therefore, we explored the possibility to reduce the lipophilic PDI(H)–dipp to PDI(H)–dipp 2− in biphasic water–acetonitrile mixtures in which the photocatalyst and the substrate are mostly dissolved in the organic phase whilst Na 2 S 2 O 4 is dissolved in water. We hypothesized that a phase‐transfer co‐catalyst could then facilitate the chemical reduction of PDI(H)–dipp by dithionite, thereby allowing us to use this reductant also in organic solvent [39] . To test this concept, we investigated the visible‐light‐mediated C α −O bond cleavage in small molecules resembling the lignin biopolymer (Table 3).…”

Photophysics of Perylene Diimide Dianions and Their Application in Photoredox Catalysis

“…We hypothesized that ap hase-transfer co-catalyst could then facilitate the chemical reduction of PDI(H)-dipp by dithionite,thereby allowing us to use this reductant also in organic solvent. [39] To test this concept, we investigated the visible-light-mediated C a À Ob ond cleavage in small molecules resembling the lignin biopolymer (Table 3). This reaction requires fairly negative reduction potentials, [40] and it is of interest from an application-oriented perspective in which the controlled depolymerization of lignin would lead to useful commodity products.…”

The kinetics of polycondensation of ?,??-dichloro-p-xylene with 4,4?-isopropylidenediphenol using benzyltriethylammonium chloride as a phase-transfer catalyst

“…1 PTC have been employed in condensation polymerization, 2-4 anionic polymerization, 5,6 and radical polymerization. [7][8][9][10][11] They have investigated the effect of PTC on the conversion and reaction mechanism. Also, the rate of polymerization was represented as a function of the feed concentration of PTC.…”