thermal rearrangement of 7,7-dichloro-[a,c]-dibenzo-[4,1,0]-bicycloheptane (1) to 5,6-dichloro-5hdibenzo-[a,c]-cycloheptene (2) was studied in the solid phase and in solvents with different polarities. thefirst-order constants at various temperatures for the rearrangement process were evaluated from theabsorption time data. the activation parameters for this rearrangement were obtained from the...

The acetylcholine receptor (AChR) from vertebrate skeletal muscle initiates voluntary movement, and its kinetics of activation are crucial for maintaining the safety margin for neuromuscular transmission. Furthermore, the kinetic mechanism of the muscle AChR serves as an archetype for understanding activation mechanisms of related receptors from the Cys-loop superfamily. Here we record currents...

The rate constants and activation parameters are reported for the oxidation of methanol, ethanol, propanol, and isopropanol by 2,2’-bipyridyl chromium peroxide (BPCP) over the temperature range of 35° to 50°C.

Reaction constants and heat release during thermophilic aerobic digestion of typical secondary and mixed sludges were determined. Maximum reaction constant, determined by measuring the amounts of biodegradable volatile suspended solids (bVSS) removed, occurred in the temperature range of 55-60 ºC. Measurement of heat releases were carried out, at the same range, by the aid of a temperature ...

The kinetics of the alkylation of the essential sulfhydryl group of papain with chloroacetic acid was studied. The variation of the second order rate constant with pH at 4.5” and 30.5’, r/2 = 0.07, is bell-shaped, with rate constants at a maximum near neutrality, approaching zero at low pH, and approaching a positive minimum at high pH. These profiles are described by a formulation which relate...

One of the fastest steps in the initial decomposition of HFCs under combustion conditions is hydrogen atom abstraction by hydroxyl radicals. We have utilized ab initio quantum mechanics and transition-state theory (TST) to calculate the temperature dependence of rate constants for the reactions of OH with CH4, CH3F, CH2F2, and CHF3. Rate constants calculated using HF/6-31G(d) frequencies and MP...

This paper deals with the extraction of L-Theanine containing Aliquat 336 as a carrier and cyclohexane as solvent across bulk liquid membrane. The optimum operation condition are as follows: extraction time of 150 min, initial concentration of theanine in the feed phase is 1.8 g/L, the carrier concentration is 0.5 M, the ion of the receiving phas...

A new approach for the calculation of vibrational energy relaxation rate constants is introduced. The new approach is based on linear response theory, and is shown to have several distinct advantages over the standard Landau–Teller formula, which is based on the Bloch–Redfield theory, namely: ~1! weak system–bath coupling is not assumed; ~2! selectivity in choosing the vibrational energy relaxa...

The reduction of oxidized glutathione GSSG by hydrated electrons and hydrogen atoms to form GSSG•⁻ is quantitative. The radical anion dissociates into GS• and GS⁻, and the S-centered radical subsequently abstracts a hydrogen intramolecularly. We observe sequential development of UV absorbance signatures that indicate the formation of both α- and β-carbon-centered radicals. From experiments perf...