Kinetic studies on the polymerization of 1.3‐dioxolane catalyzed by triethyl oxonium tetrafluoroborate

Abstract

The kinetics of the polymerization of 1.3-dioxolane with triethyl oxonium tetrafluoroborate has been studied in methylene chloride solution. The polymerization was preceded by an induction period. The addition of water to the system prolonged the induction period and decreased both rate of polymerization and molecular weight of the polymer. The induction period was found to be proportional to reciprocal of the initial catalyst concentration but to be independent of initial monomer concentration. Therefore it would appear that the induction period is mainly due to a reaction of the catalyst with water. A nearly linear relationship between the degree of polymerization and the conversion suggested that the polymerization proceeds essentially without termination and chain transfer reactions to an equilibrium conversion in the absence of water. The rate constant of propagation was estimated to be 4.3.10-21./mole sec in methylene chloride a t 3OoC. ZUSAMMENFASSUNG:Die Kinetik der Polymerisation von 1.3-Dioxolan mit Triathyloxoniumtetrafluorborat als Katalysator in Methylenchlorid als Losungsmittel wurde untersucht. Der Polymerisation geht eine Induktionsperiode voraus. Ein Zusatz von Wasser verlangert die Induktionsperiode und setzt sowohl die Polymerisationsgeschwindigkeit als auch das Molekulargewicht des Polymeren herab. Die Induktionsperiode ist proportional dem reziproken Wert der Anfangskonzentration des Katalysators, aber unabhangig von der Anfangskonzentration des Monomeren. Die Induktionsperiode scheint also hauptsachlich von einer Reaktion des Katalysators mit Wasser abzuhangen. Eine annahernd lineare Abhangigkeit zwischen dem Polymerisationsgrad und dem Umsatz deutet darauf hin, daB die Polymerisation in Abwesenheit von Wasser im wesentlichen ohne Abbruchs-und fibertragungsreaktionen bis zu einem Gleichgewicht verlauft. I n Methylenchlorid ist die Geschwindigkeitskonstante der Wachstumsrea,ktion bei 30°C 4,3.10-2 I/mol sec.

Stable organic cation salts: Ion pair equilibria and use in cationic polymerisation

“…+ It is unlikely that the simple carboxonium ion --~H2 is the effective active centre as favoured by a number of research groups (119,147) (122).…”

“…Some of the more important monomers whose ring opening polymerisations have been induced by stable cation salts include, 1,4-epoxides, notably tetrahydrofuran (20, 1t2, I13), 1,2-epoxides (1t4), 1,3-episulphides (thietans) (33,53), 1,2-episulphides (thiiranes) (53), azetidines (115,116), aziridines (117), the cyclic formals, 1,3-dioxolan (23,54,(118)(119)(120), and 1,3-dioxepan (118,119), trioxane (121,122) and more recently lactones (123). Aldehydes (124) may also be included since these molecules can be regarded as the smallest possible oxygen hetero-cycles giving polymers whose structures are analogous to those from epoxides e.g.…”

Block and star block copolymers by mechanism transformation. II. Synthesis of poly(DOP-b-St) by combination of ATRP and CROP

“…11 Because of the existence of tertiary oxonium ions and carboxonium ions during the cationic polymerization of acetals (e.g., trioxane, DOL, and DOP), 12 styrene was once cationically copolymerized with these monomers to prepare random copolymers. [13][14][15][16] However, the content of styrene unit in the copolymer was fairly low when high-molecular-weight copolymers was prepared, this was caused by the chain-transfer reaction of styryl cation to styrene monomer, thus no block copolymers of DOL or DOP with styrene were reported. Although DOL and DOP only polymerize cationically, the polymerization of styrene can be conducted by anionic, cationic, or radical method, so the mechanism transformation method might be the most probable route to prepare poly(DOP-…”

Cationic Copolymerization of 1,3-Dioxolane and Isoprene

“…15 Commercial isoprene(Ip) of Phillips Petroleum Co. was dried over calcium hydride and fractionally distilled.…”

“…14 In the present study, it was intended to synthesize high molecular weight copolymer of DOL and Ip utilizing the living nature of the polymerization of DOL. 15 The results on the copolymerization carried out within a high vacuum system using Et3OBF 4 as an initiator are given in Table III. Although the rate of copolymerization was extremely slow, a copolymer with molecular weight as high as 1.6 x 10 5 was successfully prepared when the molar ratio of DOL to Ip in feed was high.…”