Effective promotion of tetrahydrofuran polymerization initiated with heteropolyacid

Abstract

Tetrahydrofuran was polymerized using the heteropolyacid H 3 PW 12 O 40 as the initiator and ethylene oxide as the promoter, which effectively increased the rate and conversion of the polymerization. Water and butylene glycol were used to control the molecular weight of the product in the range of 1000 -3000. The polymer was found to be polyether glycol containing 10 -22 mol % oxyethylene moieties with hydroxyl groups at both chain ends. The melting point was ϳ 10°C lower compared to polytetramethylene ether glycol having the same molecular weight. The concentration of active species remained unchanged in the main period of the polymerization, indicating the absence of chain termination. The values of the chain propagation rate constant of tetrahydrofuran polymerization at 0 and 20°C were found to be 3.78 ϫ 10 Ϫ3 and 1.98 ϫ 10 Ϫ2 L mol Ϫ1 s Ϫ1 , respectively, which are close to the rate constant of chain propagation of tetrahydrofuran on ionic active species.

Preparation of Polyether Triol and Three-Armed Polyether Triol by Tetrahydrofuran Polymerization Initiated with Heteropolyacid

“…The peaks of EO moieties in Figure 1 were assigned as we reported in a previous paper [16] and the peaks of TMP moieties were assigned by using the spindecoupling technique.…”

“…In previous paper [16] we reported that the polymerization of THF initiated by PW 12 in low concentration at 0 8C did not proceed or proceeded very slowly. The reaction started normally upon addition of EO, and the propagating chains started with oxyethylene hydroxyl groups (HOCH 2-CH 2 O1) as shown by reaction 1 in Scheme 1.…”

“…The average hydroxyl endgroup functionality was close to 3, the polymerization yield was around 80% and molecular weight of the threearmed polyether triol was 3 000-4 000. the preparation of star-shaped poly(THF) with terminals other than hydroxyls. [10 -15] In our previous paper [16] the heteropolyacid-H 3 PW 12 O 40 (12-tungstophosphoric acid) was used together with ethylene oxide (EO) to initiate the THF polymerization, and the polyether was obtained in high conversion with controllable molecular weight and relatively narrow molecular weight distribution. The initiator is not particularly corrosive, recoverable, reusable and suitable for commercial use in polyether production.…”

Calcium Salts of Tungstophoric Acid Supported on Silica as Novel Catalysts for Tetrahydrofuran Polymerization

“…Heteropolyacids have many applications in science researches [4][5][6][7] and industrial production [8], and it could also replace HF, H 2 SO 4 , and other traditional inorganic corrosive acids in the synthesis of polytetrahydrofuran in mild conditions [9,10]. Because of low specific area (\10 m 2 /g) and dissolution in polar solution, heteropolyacid is not easy to separate from the reaction mixture and its catalytic reaction stability is poor [11].…”

β-Pinene cationic polymerization using Keggin heteropolyacid catalysts

“…In these reactions, the aimed catalysts acted as polymerization initiators, and the reaction mechanism was accepted commonly as cationic polymerization [13][14][15][16][17][18][19]. Burrington et al [20] have published on the use of a heteropolyacid salt as catalyst for the cationic polymerization of isobutylene.…”