Oxidation of cyclohexanol free from peroxide by carbon tetrachloride under the influence of gamma radiation was carried out both for air saturated and deareated systems. Large values for the formation of HCl are obtained. A kinetic expression consistent with experimental observations has been derived.
Volume reduction studies were carried out on low level radioactive plastic wastes containing polyethylene, PVC and neoprene
by melt densification. The optimized temperature for melting of plastics was between 170 and 180 °C. Based on laboratory scale
studies. Plant scale studies were planned and conducted. The volume reduction factors obtained were around 30, which was 6-10
times higher than that of the conventional compaction process. Thermogravimetry and infrared spectroscopy were used to investigate
the thermal and structural properties of the given materials. The effect of the presence of salts like potassium permanganate
and hydrazine sulphate on the thermal properties of the materials was also evaluated. Leaching studies were also performed
on melt-densified specimens in the laboratory. The average leach index was observed to be around 9, which was higher than
the minimum stipulated value.
Authors:G. Rama Rao, V. Manchanda, and P. Natarajan
Present work summairzes a method for the estimation of uranium in the presence of plutonium involving the reduction of uranium to U/IV/ and plutonium to Pu/III/ by Zn/Hg/ followed by the selective oxidation of Pu/III/to Pu/IV/with HNO3 catalyzed by molybdate in the presence of large sulphate concenration [5M H2SO4+1.5M /NH4/2SO4]. The oxidation of U/IV/ by K2Cr2O7 is then carried out in the presence of excess of Fe/III/ and Al/NO3/3 to a sharp potentiometric end point. R.S.D. obtained for 20 determinations of uranium /3–6 mg/ was 0.3% in the presence of 0.35 mg of plutonium. Larger quantity for plutonium was found to interfere.
The kinetics of chlorine isotope exchange between chloramine-B /CAB/ and chloride has been studied using ion-exchange separation and tracer technique. McKay's plot are linear. The exchange reaction is fast in acidic medium, very slow in neutral medium and does not take place in alkaline medium. In the acidic range the exchange is maximum at pH 3.3. The rate of exchange decreases at pH >3.3 and <3.3. The order with respect to CAB and chloride is unity. The order with respect to [H+] is unity at pH>5. Addition of neutral salt or parent compound has no effect on the rate of exchange. Activation energy and activation entropy for this exchange reaction have been calculated.
Several adducts of U(IV) and Th(IV) with 1,1,1,2,2,3,3-heptafluoro-7,7-dimethyl-4,6-octanedione (FOD) as -diketone and a variety of neutral oxodonors were synthesized and characterized by visible spectral, proton magnetic resonance as well as thermogravimetric studies. Adducts with dimethylformamide (DMF) were found to be most volatile, whereas with trioctylphosphine oxide (TOPO) were quite susceptible towards decomposition.
Authors:V. Sarma, Pullela Srinivas, V. Anuradha, and J. Rao
The dried fruits of
are extensively used in Ayurvedic medicinal preparations. A simple and convenient HPTLC method has been developed for standardization of the plant material using the two major constituents, pellitorine and dihydropiperlonguminine, as markers. The stationary phase was silica gel 60 F
, hexane-ethyl acetate, 75 + 25 (
), was used as mobile phase, and detection was at
= 260 nm. The method is characterized by high sensitivity and linearity over a wide range of concentrations. The results obtained were evaluated statistically.
Authors:S. Sahakundu, S. Marathe, V. Rao, V. Bhargava, and R. Iyer
A new method for obtaining radiochemically pure67Cu from highly active fission product solutions is described. The method is based on the solvent extraction of the Cu(II)-diethyldithiocarbamate
complex in n-butyl acetate in the presence of hold-back carriers for Ni, Co, Mn, Mo, rare earths, Cd, Te and Sb, and subsequent
purification steps involving scavengings for Ag, Ba, Sr and Fe followed by an anion-exchange purification step for decontamination
from Te. Copper is finally extracted as the α-benzoin oxime complex in which form it is mounted and counted. The method has
several advantages over other methods in that decontamination is very high and it is sufficiently fast considering the stringent
radiochemical purity achieved. The67Cu separated by this procedure from a one-day-old mixture of fission products arising from 1010 fissions was found to be completely free of any contamination.