Kinetics of vanadium (V) catalyzed oxidation of gallic acid by potassium bromate in acid medium

Pythium aphanidermatum, with an optimum temperature for growth at 35C, grew well and was readily isolated from soil on pimaricin–vancomycin medium (MPVM) when incubated for24 h at 38–40C. The pH of the medium affected recovery; maximum numbers developed above pH 6.0. Other Pythium spp. were recovered on MPVM at 20–25C, but were excluded by incubation at 38–40C. These Pythium spp. included P. ultimum, P. paroecandrum, P. irregulare, P. mamillatum, and an unidentified Pythium sp. These species grew well and were readily isolated from soil on gallic acid medium (GAM) when incubated for 24–48 h at 20C. P. aphanidermatum and P. myriotylum grew from mycelium on GAM, but their oospores did not germinate nor could they be isolated from soil on this medium. P. myriotylum grew well on MPVM, but was only rarely isolated, even from soils with known high potential for disease caused by P. myriotylum. Propagules of Pythium were enumerated by a plate-dilution frequency method or by a smear-plate method in serial dilutions of soil in 0.3% water agar. This differential isolation method is valuable for studies on the ecology, survival, and inoculum potential in soils with mixed populations of P. aphanidermatum and other Pythium spp.

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ChemInform Abstract: KINETICS OF OXIDATION OF GLYCINE AND VALINE BY CHLORAMINE-T IN HYDROCHLORIC ACID MEDIUM

Chemischer Informationsdienst ◽

10.1002/chin.197920135 ◽

1979 ◽

Vol 10 (20) ◽

Author(s):

N. M. M. GOWDA ◽

D. S. MAHADEVAPPA

Keyword(s):

Hydrochloric Acid ◽

Acid Medium ◽

Kinetics Of Oxidation ◽

Hydrochloric Acid Medium ◽

Chloramine T ◽

Kinetics Of

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Osmium(VIII) Catalyzed Oxidation of Acetone and Ethylmethyl Ketone by Chloramine-T

Zeitschrift für Naturforschung B ◽

10.1515/znb-1972-1010 ◽

1972 ◽

Vol 27 (10) ◽

pp. 1161-1163 ◽

Cited By ~ 17

Author(s):

S. P. Mushran ◽

R. Sanehi ◽

M. C. Agraval

Keyword(s):

Acidic Medium ◽

Present Note ◽

Alkaline Media ◽

Alkaline Solutions ◽

Slow Step ◽

First Order ◽

Chloramine T ◽

Kinetics Of ◽

Catalyzed Oxidation ◽

High Redox Potential

The Osmium (VIII) catalyzed oxidation of acetone and ethylmethyl ketone by chloramine-T, in highly alkaline solutions showed first order dependence to chloramine-T and osmium (VIII). The order of the reactions with respect to alkali and ketone were found to be fractional, being ~-0.82 and 0.3 respectively. No effects of ionic strength were evident. The mechanism has been proposed on the basis of the formation of a complex between N-chlorotoluene-p-sulfonamide and osmium (VIII) in the slow step, which in turn oxidizes the enol anion of the reducing substrate in the fast step.During the study of the mechanism of oxidations by chloramine-T, the kinetics of the oxidation of α-hydroxy acids 1 in presence of osmium (VIII) as catalyst, glycerol2 in neutral and alkaline media, p-cresol3 in an acidic medium, hexacyanoferrate (II)4 in a feebly acidic medium (pH 6-7) and aliphatic aldehydes 5 in alkaline media have been investigated.Despite the high redox potential6 of the chloramine-T/toluene sulfonamide system (1.138 V at pH 12), the oxidation of acetone does not take place in absence of catalyst and that of ethylmethyl ketone proceeds only in highly alkaline solutions7 (NaOH>0.01 M). In the present note the kinetics of the osmium (VIII) catalyzed oxidation of acetone and ethylmethyl ketone have been recorded.

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