Novelties of solid-liquid phase transfer catalysed synthesis of p-toluenesulfonyl fluoride from p-toluenesulfonyl chloride

Organic sulfonyl fluorides are of interest owing to their insecticidal, germicidal and enzyme inhibitory properties. In the current work, synthesis of p-toluenesufonyl fluoride was accomplished by reacting p-toluenesulfonyl chloride with solid potassium fluoride using PEG-400 as a catalyst under solid-liquid phase transfer catalysis (S-L PTC) at 30 °C. p-Toluenesulfonyl fluoride is used as peroxygen bleach activator. It also finds use in the treatment of Alzheimer's disease. The mechanism is based on homogeneous solubilization of solid. PEG forms a complex with metal cation which associates with the nucleophile and it participates in SN₂ type reactions. The reaction is intrinsically kinetically controlled. A complete theoretical analysis is done to determine both the rate constant and equilibrium constant from the same set of data. The activation energy and Gibbs free energy are also calculated.     

Determination of plutonium by secondary coulometric titration with internally generated iron(II)

The method for plutonium determination based on secondary controlled-potential coulometry, as described by SHULTS, is applied for analysis in the range of 0.1–5 mg plutonium. The method involves the oxidation of plutonium to Pu(VI) with perchloric acid followed by its reduction by an internally generated ferrous mediator. This is a two step procedure, involving the reduction of Pu(VI) and Fe(III) to a mixture of Pu(III) and Fe(II), followed by the oxidation of Pu(III) and Fe(II) to Pu(IV) and Fe(III), respectively. The net results is the reduction of Pu(VI) to Pu(IV), measured as the difference between the currents consumed during the reduction and oxidation steps. The original method of SHULTS involves 10–25 mg plutonium for each determination. Since the present method is intended for the analysis of smaller amounts of plutonium, the oxidation procedure described in the original version had to be modified. The method is found to work satisfactorily with a precision better than 0.1% at 5 mg level and 1.2% for 0.1 mg plutonium.     

QCD estimates for associated charm production by weak neutral currents

We give quantitative estimates for associated charm production in neutrino and antineutrino induced neutral current interactions, based on (a) quantum chromodynamics (QCD) and (b) the quark parton model (QPM) and a phenomenological generalization thereof. We emphasize the need for a precise measurement of the ratio σ(v_μN→v_μe⁺X)/σ(v_μN→μ^?X) and the corresponding ratio for antineutrinos, as these can provide clean tests of certain characteristic features of QCD. Bounds are obtained for single charm production by charm-changing neutral currents.     

On the size effects in an electron hole drop

It is found theoretically that the work function in an (EHD) decreases as the number of pairs in the drop falls. This is in qualitative agreement with the experimental results.     

Using genetic algorithms to characterize ferrofluid topographies in externally applied magnetic fields

Both ferrofluidics and genetic algorithms are relatively new fields. Due to complex physical interactions, ferrofluidic topographies and assemblies have only been solved using finite time step, Lattice Boltzmann, and finite-element methods in very simple magnetic field configurations. In this paper, we show that it is possible (and highly advantageous) to employ genetic algorithms to solve for the fluid topographies, which can be extended to include more complex magnetic fields.     

Synthesis of compounds related to santonin

Proceedings - Mathematical Sciences - Following the methods used in the synthesis of santonin the synthesis of compounds related to santonin has been described.