- Synthesis and properties of poly
-
The synthesis of poly has been performed in four steps.Chlorination of pentaerythritol produced a mixture of halogenated alcohols, which, in an alkaline medium, led to a mixture of hydroxylated and chlorinated oxetanes.Of these, the bis(3-chloromethyl) oxetane (BCMO) was etherified with C6F13C2H4OH via phase-transfer catalysis to yield the mono- and di-substituted fluorinated oxetanes.In a last step, the mono-substituted oxetane was cationically polymerized using BF3*OEt2 as the catalyst, and was characterized by 1H and 13C NMR spectroscopy.Finally, several physical properties have been determined such as the viscosity, glass transition and decomposition temperatures, and surface properties.
- Ameduri, Bruno,Boutevin, Bernard,Karam, Lina
-
-
Read Online
- Chemical transformation of 3-bromo-2,2-bis(bromomethyl)-propanol under basic conditions
-
The mechanism of the spontaneous decomposition of 3-bromo-2,2- bis(bromomethyl)propanol (TBNPA) and the kinetics of the reaction of the parent compound and two subsequent products were determined in aqueous solution at temperatures from 30 to 70 °C and pH from 7.0 to 9.5. TBNPA is decomposed by a sequence of reactions that form 3,3-bis(bromomethyl)oxetane (BBMO), 3-bromomethyl-3-hydroxymethyloxetane (BMHMO), and 2,6-dioxaspiro[3.3]-heptane (DOH), releasing one bromide ion at each stage. The pseudo-first-order rate constant of the decomposition of TBNPA increases linearly with the pH. The apparent activation energy of this transformation (98 ± 2 KJ/mol) was calculated from the change of the effective second-order rate constant with temperature. The pseudoactivation energies of BBMO and BMHMO were estimated to be 109 and 151 KJ/mol, respectively. Good agreement was found between the rate coefficients derived from changes in the organic molecules concentrations and those determined from the changes in the Br- concentrations. TBNPA is the most abundant semivolatile organic pollutant in the aquitard studied, and together with its byproducts they posess an environmental hazard. TBNPA half-life is estimated to be about 100 years. This implies that high concentrations of TBNPA will persist in the aquifer long after the elimination of all its sources.
- Ezra, Shai,Feinstein, Shimon,Bilkis, Itzhak,Adar, Eilon,Ganor, Jiwchar
-
-
Read Online
- PREPARATION OF SOME SPIROCYCLIC OXETANES
-
Syntheses and spectroscopic properties of some oxetanes derived from pentaerythritol are discussed.
- Odeh, A.M.S.,Usta, J.A.,Issidorides, C.H.
-
p. 189 - 192
(2007/10/02)
-