Über Tertiäre Oxoniumsalze, II

Meerwein, Hans; Battenberg, Ernst; Gold, Heinrich

doi:10.1002/prac.19391540305

Cited by 305 publications

(39 citation statements)

References 17 publications

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“…The polymerization was carried out in methylcyclohexane, at 0 ~ with triethyloxonium tetrafluorborate as catalyst. This system was prepared by the method described by Meerwein et al [7]. The polymer was purified by precipitation of an acetone solution into methanol.…”

Section: Methodsmentioning

confidence: 99%

Effect of molecular weight and temperature on the isothermal crystallization of poly(oxetane)

Pérez¹,

Bello²,

Fatou³

1984

Colloid & Polymer Sci

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Poly(oxetane) fractions ranging in number-average molecular weights from 7800 to 157000 have been isothermally crystallized in the temperature range from-50 to 19 ~ using dilatometric and calorimetric techniques. In both cases, reproducible isotherms were obtained with an Avrami exponent equal to three. The crystallization rate against crystallization temperature presents a maximum at -30 ~ The level of crystallinity changes with molecular weight and the influence of this parameter on the rate of crystallization is pronounced. The crystallization temperature coefficient was studied using nucleation theory and it was found an slight increase in the basal interfacial free energy for the lowest molecular weight fraction. For the analysis of the temperature coefficient at the higher undercoolings, different approximations for the free energy of fusion and the transport term have been considered. The conclusion of this analysis is that, independently of these approximations, the obtained temperature coefficients are the same.

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Section: Methodsmentioning

confidence: 99%

Effect of molecular weight and temperature on the isothermal crystallization of poly(oxetane)

Pérez¹,

Bello²,

Fatou³

1984

Colloid & Polymer Sci

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“…6 2-Methyl-1,3-dioxolenium perchlorate [CH3C+O2-(CH2)2 · ClO4 -](MDO) and 2,2'-octamethylenebis-1,3-dioxolenium perchlorate [(CH2)4C+O2(CH2) 2 · ClO4 -]s(OMDO) were prepared as described in a previous paper. 7 …”

Section: Reagentsmentioning

confidence: 99%

Cationic Copolymerization of Tetrahydrofuran with ε-Caprolactone

Yamashita

Ito

Chiba

et al. 1972

Polym J

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“…Reactions that give RI and ene must also give ThO [Eqns (1) and (2)]. Therefore, the sum of the yields of RI and ene should equal the yield of ThO.…”

Section: Reactions With Imentioning

confidence: 99%

“…4 Recently, we found that thianthrene cation radical perchlorate (Th Á ClO 4 À ) reacts easily with a variety of primary and secondary alcohols (Scheme 1), permitting the isolation of crystalline 5-(alkoxy)thianthrenium perchlorates (1). [5][6][7] The availability of these salts allowed us to begin a systematic study of their reactions with nucleophiles.…”

Section: -3mentioning

confidence: 99%

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Reactions of nucleophiles with 5-(alkoxy)thianthrenium ions

Liu

Shine

Zhao

1999

J. Phys. Org. Chem.

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Reactions of 5-(alkoxy)thianthrenium perchlorates (1) with weakly basic nucleophiles Br À , IÀ and PhS À (X À ) in MeCN and DMSO led to S N 2 substitution, E2C elimination, and reaction at sulfonium sulfur to extents depending on the structure of the alkoxy group (RO) in 1 and the nucleophile. Three types of reaction occurred with R = cyclopentyl (1a), cyclohexyl (1b), cis-(1c) and trans-4-methylcyclohexyl (1d) and cycloheptyl (1e), and X À = Br À and I À . That is, S N 2 reaction gave RX and thianthrene 5-oxide (ThO), E2C reaction gave cycloalkene and ThO and reaction at sulfonium sulfur gave X 2 , thianthrene (Th) and cycloalkanol (ROH). Earlier work with R = Me (1f) and Et (1g) and X À = I À , Br À had shown that only S N 2 reaction occurred. In contrast with reactions of halide ions, reactions of PhS À with 1b-g occurred only at sulfonium sulfur, giving Th, ROH and PhSSPh (DPDS). For comparison with 1, reactions of Ph 2 S OMe (2) with I À and PhS À were carried out. Reaction with I À gave only Ph 2 S=O and MeI (S N 2). Reaction with PhS À gave very little PhSMe (S N 2) but mainly Ph 2 S, MeOH, and DPDS from reaction at sulfonium sulfur. The differences in nucleophilic pathways (PhS À vs Br À and I À ) in reactions with 1 and 2 are attributed to differences in thiophilicities of the nucleophiles. The thiophilicity of PhS À dominates its reactions with 1 and 2. The direction toward products (Th, ROH and DPDS) in these reactions is compounded by the ease of displacement of alkoxide from 1 and 2 by PhS À , and the ease with which, subsequently, thiophilic PhS À attacks sulfenyl sulfur in the resulting phenylthiosulfonium ion.

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Über Tertiäre Oxoniumsalze, II

Cited by 305 publications

References 17 publications

Effect of molecular weight and temperature on the isothermal crystallization of poly(oxetane)

Effect of molecular weight and temperature on the isothermal crystallization of poly(oxetane)

Cationic Copolymerization of Tetrahydrofuran with ε-Caprolactone

Reactions of nucleophiles with 5-(alkoxy)thianthrenium ions

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