Reactions of cyclic ethers

Gritter, Roy J.

doi:10.1002/9780470771075.ch9

Cited by 22 publications

(3 citation statements)

References 280 publications

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“…The secondary oxonium ion involves a highly strained three-membered ring (ring strain of EO molecule is equal to 114.3 kJ/mol) while the tertiary oxonium ion involves a five-membered ring for which the ring strain is much lower (ring strain of THF molecule is equal to 23.6 kJ/mol). 18 Thus, the much higher reactivity of the protonated EO results from the release of the considerable strain energy upon opening of the oxonium ion ring, which outweighs the inherently lower reactivity of the secondary oxonium ions.…”

Section: Determination Of Concentrations Of Secondary and Tertiary Ox...mentioning

confidence: 99%

Coexistence of Activated Monomer and Active Chain End Mechanisms in Cationic Copolymerization of Tetrahydrofuran with Ethylene Oxide

1999

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Cationic copolymerization of tetrahydrofuran (THF) with ethylene oxide (EO) in the presence of diols proceeds with simultaneous participation of secondary and tertiary oxonium ions. This process comprises therefore some features of the activated monomer (AM) and the active chain end (ACE) mechanisms. The mechanism of copolymer formation was evaluated, and the kinetics of competing reactions involving both secondary and tertiary oxonium ions with nucleophiles present in the system was studied. The apparent rate constants were derived, allowing the estimation of the influence of copolymerization conditions on the composition and microstructure of copolymers.

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Section: Determination Of Concentrations Of Secondary and Tertiary Ox...mentioning

confidence: 99%

Coexistence of Activated Monomer and Active Chain End Mechanisms in Cationic Copolymerization of Tetrahydrofuran with Ethylene Oxide

1999

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Section: Introductionmentioning

confidence: 99%

“…It is well-known that addition reactions of oxirane with protic reagents such as amines, alcohols, thiols, phenols, and carboxylic acids using appropriate acidic or basic catalysts proceed to give the corresponding 1:1 adducts containing hydroxyl groups. These reactions have been widely used , in organic synthesis and polymer synthesis. The other interesting reaction of oxiranes is the ring-opening polymerization, which proceeds smoothly to produce the corresponding polyethers when catalyzed by appropriate strong acids or bases.…”

Section: Introductionmentioning

confidence: 99%

A Novel Synthesis of Poly(ester-alt-sulfide)s by the Ring-Opening Alternating Copolymerization of Oxiranes with γ-Thiobutyrolactone Using Quaternary Onium Salts or Crown Ether Complexes as Catalysts

1998

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Poly(ester-alt-sulfide) (polymer 1) was synthesized by the alternating copolymerization of glycidyl phenyl ether (GPE) with gamma-thiobutyrolactone (TBL) catalyzed by either quaternary onium salts or crown ether complexes. The copolymerization proceeded to produce polymer 1 with good yields in neat or in various organic solvents at 30-120 degreesC, in which quaternary onium salts having Cl- as a counteranion such as tetrabutylammonium chloride (TBAC) had higher activity than quaternary onium salts such as tetrabutylammonium bromide having Br- as a counteranion. It was also found that the alternate copolymer (polymer 1) of GPE with TBL was obtained selectively under different feed ratios of GPE and TBL, although ring-opening homopolymerizations of GPE and TBL did not proceed. Copolymerizations of various oxiranes such as butyl glycidyl ether, styrene oxide, and 1,2-hexene oxide with TBL catalyzed by TBAC also proceeded, and the corresponding poly(ester-alt-sulfide)s (polymers 2, 3, and 4) were obtained under the same conditions as for the synthesis of polymer 1.

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Synthesis of polyethers with unsymmetrical structures by the polyaddition of 3‐ethyl‐3‐(glycidyloxymethyl)oxetane with diacyl chlorides

Nishikubo

Kameyama

Izawa

2000

J. Polym. Sci. A Polym. Chem.

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Polyethers with unsymmetrical structures in the main chains and pendant chloromethyl groups were synthesized by the polyaddition of 3‐ethyl‐3‐(glycidyloxymethyl)oxetane (EGMO) with certain diacyl chlorides with quaternary onium salts or pyridine as catalysts. The unsymmetrical polyaddition of EGMO containing two different cyclic ether moieties such as oxirane and oxetane groups with terephthaloyl chloride proceeded smoothly in toluene at 90 °C for 6 h to give polymer 1 with a number‐average molecular weight (Mn) of 51,700 in a 93% yield when tetrabutylammonium bromide (TBAB) was used as a catalyst. The polyaddition also proceeded smoothly under the same conditions when other quaternary onium salts, such as tetrabutylammonium chloride, tetrabutylammonium iodide, tetrabutylphosphonium chloride, and tetrabutylphosphonium bromide, and pyridine were used as catalysts. However, without a catalyst no reaction occurred under the same reaction conditions. Polyadditions of EGMO with isophthaloyl chloride and adipoyl chloride gave polymer 2 (Mn = 28,700) and polymer 3 (Mn = 25,400) in 99 and 65% yields, respectively, under the same conditions. The chemical modification of the resulting polymer, polymer 1, which contained reactive pendant chloromethyl groups, was also attempted with potassium 3‐phenyl‐2,5‐norbornadiene‐2‐carboxylate with TBAB as a phase‐transfer catalyst, and a polymer with 65 mol % pendant norbornadiene moieties was obtained. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 368–375, 2001

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Reactions of cyclic ethers

Cited by 22 publications

References 280 publications

Coexistence of Activated Monomer and Active Chain End Mechanisms in Cationic Copolymerization of Tetrahydrofuran with Ethylene Oxide

Coexistence of Activated Monomer and Active Chain End Mechanisms in Cationic Copolymerization of Tetrahydrofuran with Ethylene Oxide

A Novel Synthesis of Poly(ester-alt-sulfide)s by the Ring-Opening Alternating Copolymerization of Oxiranes with γ-Thiobutyrolactone Using Quaternary Onium Salts or Crown Ether Complexes as Catalysts

Synthesis of polyethers with unsymmetrical structures by the polyaddition of 3‐ethyl‐3‐(glycidyloxymethyl)oxetane with diacyl chlorides

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