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 degrees 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 linearlywith 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
S
Department of Geological and Environmental Sciences, Ben-Gurion University of the Negev, Israel. shaie@bgumail.bgu.ac.il
Feinstein
Shimon
S
Bilkis
Itzhak
I
Adar
Eilon
E
Ganor
Jiwchar
J
D006207:Half-Life; D006863:Hydrogen-Ion Concentration; D007220:Industrial Waste; D007700:Kinetics; D020005:Propanols / Q000032:analysis / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis*
C500381:3-bromo-2,2-bis(bromomethyl)propanol; D007220:Industrial Waste; D020005:Propanols; D014874:Water Pollutants, Chemical