scholarly journals Reactivity Studies of Thiophosgene and its Halo Versions towards Diazo Derivatives

Author(s):  
SUDERSHAN GONDI

The reactions of thiophosgene with diazo derivatives gives dichloro-alkene derivatives and cyclized, 1,2,3-thiadiazoles respectively. The product formation is mainly depending on substitutions on diazo substrates. When its halo versions, CSBr2 and in combination with bromide ion, CSBr2 less reactive than bromide ion with disubstituted diazo, give gem-dihalo derivatives whereas more reactive with mono substituted diazo to gives 1,2,3-thiadiazoles. In case CSI2 irrespective of substitution on diazo, iodide ion is more reactive then CSI2 was observed.

Author(s):  
P.U. Singare

The present study deals with non-destructive application of radioactive tracer isotopes to evaluate the performance of Tulsion A-33 (nuclear grade) and Indion NSSR (non-nuclear grade) anion exchange resins. The performance evaluation was done by carrying out the iodide and bromide ion-isotopic exchange reactions using the above resins. It was observed that at a constant temperature of 40.0 °C, as the concentration of labeled iodide ion solution increases 0.001 M to 0.004 M, the percentage of iodide ions exchanged increases from 58.0% to 64.0% for Tulsion A-33 resins; and from 48.4% to 50.8% for Indion NSSR resins. Similarly in case of bromide ion-isotopic exchange reaction under identical experimental conditions, the percentage of bromide ions exchanged increases from 45.6% to 50.4% for Tulsion A-33 resin; and from 39.8% to 44.6% for Indion NSSR resin. It was also observed that during iodide ion-isotopic exchange reaction at 40.0 °C, using 1.000 g of ion exchange resins and 0.003 M labeled ionic solution, using Tulsion A-33 resin the values of specific reaction rate (min-1), amount of iodide ion exchanged (mmol), initial rate of iodide ion exchange (mmol/min) and log Kd were 0.229, 0.469, 0.107 and 10.6 respectively, which was higher than the values of 0.167, 0.375, 0.063 and 7.6 respectively as obtained by using Indion NSSR resins under identical experimental conditions. The overall results indicate superior performance of Tulsion A-33 over Indion NSSR resin under identical operational parameters.


Author(s):  
P.U. Singare

Radioactive tracer isotopes 131I and 82Br were used to characterize anion exchange resins Purolite NRW-8000 and Duolite A-368 by application of nondestructive technique. The resin characterization was based on their performance during iodide and bromide ion-isotopic exchange reactions. It was observed that during the iodide ion-isotopic exchange reaction at a constant temperature of 40.0 °C, as the concentration of labeled iodide ion solution increases from 0.001 mol/L to 0.004 mol/L, the percentage of iodide ions exchanged increases from 62.10% to 68.10 % using Purolite NRW-8000 resins and from 44.20% to 46.80% using Duolite A-368 resins. Also at a constant temperature of 40.0 °C, 1.000 g of ion exchange resins and 0.003 mol/L labeled iodide ion solution, the values of specific reaction rate (min-1), amount of iodide ion exchanged (mmol), initial rate of iodide ion exchange (mmol/min) and log Kd were calculated as 0.260, 0.500, 0.130 and 11.8 respectively for Purolite NRW-8000 resin, which was higher than the respective values of 0.130, 0.345, 0.045 and 6.7 as that obtained for Duolite A-368 resins. The similar trend was observed for the two resins during bromide ion-isotopic exchange reaction. From the overall results it appears that under identical experimental conditions, Purolite NRW-8000 resins show superior performance over Duolite A-368 resins. It is expected here that the present nondestructive technique can be extended further for characterization of different industrial grade ion exchange resins, which will help in their selection for specific industrial application.


1989 ◽  
Vol 61 (03) ◽  
pp. 386-391 ◽  
Author(s):  
Guido Tans ◽  
Truus Janssen-Claessen ◽  
Jan Rosing

SummaryIn this paper we report a method via which enzymatically active products formed during prothrombin activation can be detected by simple photographic means after SDS-gel electrophoresis, blotting onto a nitrocellulose membrane and visualization with the chromogenic substrate, S2238. After amidolytic detection the same nitrocellulose membrane can also be used for immunologic detection of prothrombin activation products, thus allowing a complete description of product formation during prothrombin activation.The detection limit of the so-called “amidoblot” is approximately 3 ng thrombin per gel sample which is comparable to the sensitivity of immunoblotting.It is further shown that the amidoblot technique can also be applied to other coagulation factors for which a suitable chromogenic substrate is available (factor XIIa, kallikrein, factor XIa, factor Xa, plasmin and activated protein C).


1974 ◽  
Vol 76 (1) ◽  
pp. 178-188 ◽  
Author(s):  
H. Lübbert ◽  
K. Pollow ◽  
R. Wagner ◽  
J. Hammerstein

ABSTRACT The effects of ethanol on kinetic parameters of placental Δ5-3β-hydroxysteroid dehydrogenase were studied. In the presence of high pregnenolone concentrations (50 μm, [S] > Km) the microsomal enzyme preparation exhibited an almost linear increase in activity as the ethanol concentration in the medium was raised from 2.5 to 15 % (v/v). At lower substrate concentrations ([S] << Km) ethanol caused inhibition. Other effects of ethanol were: linearity of product formation with time was prolonged; the maximal velocity was markedly increased; the Km for pregnenolone slightly decreased with increasing ethanol concentrations (2.5 to 10 %, v/v) whereas the Km for NAD remained the same. The pH and temperature optima of the reaction were unaffected by ethanol. Other organic solvents caused similar effects.


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