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Najībābād, India

Kumar M.,Sahu Jain PG College | Singh B.R.,Sahu Jain PG College
Oriental Journal of Chemistry | Year: 2014

Thermodynamic protonation constants of dimethyl barbituric acid [DMBA], Diphenyl barbituric acid [DPBA], di-o-tolyl barbitiuric acid[D-O-TBA], di-m-tolyl barbituric acid [D-m-TBA], di-p-tolyl, barbituric acid [D-p-TBA], di-o-xylyl barbituric acid [D-o-XBA], di-m-xylyl barbituric acid [ D-m-XBA], di-p-xylyl barbituric acid [D-p-XBA], di-± napthyl barbituric acid [D-±-NBA] and di-panisyl barbituric acid [D-p-ABA] have been determined in different mole fraction of deoxane [ 0.175 - 0.350 ] at 20, 30, and 40 ± 0.100°C. The thermodynamic protonation constant [pKT a ] values do not vary linearly with reciprocal of dielectric constant of medium, but a plot of pkT a versus the mole fraction of dioxane is linear at all given temperatures. The mean ionic radii are for barbiturates ions, being in the region of 2.12 - 2.72 A° , slightly increases with dioxane percentages. The values of Δ G °, ΔH° and Δ S° have been evaluated. The effect of temperature as well as medium effect are briefly discussed. Source


Kumar M.,Sahu Jain PG College | Kumar M.,R S M Pg College | Vishvakarma P.P.,Sahu Jain PG College | Vishvakarma P.P.,R S M Pg College | And 2 more authors.
Oriental Journal of Chemistry | Year: 2015

Thermodynamic deprotonation constants [pKT a] of dimethyl thiobarbituric acid [DMTBA], diphenyl thiobarbituric acid [DPTBA], di-o-tolyl thiobarbituric acid[DOTTBA], di-m-tolyl thiobarbituric acid [DMTTBA], di-p-tolyl, thiobarbituric acid [DPTTBA], di-o-xylyl thiobarbituric acid [DOXTBA], di-p-xylyl thiobarbituric acid [DPXTBA], di-α naphthyl thiobarbituric acid [DANTBA] and di-β-naphthyl thiobarbituric acid [DBNTBA] have been determined in different mole fraction of dioxane [0.175-0.350] at 20, 30, and 40 ± 0.10° C. The plot of the thermodynamic deprotonation constant [] versus the mole fraction of dioxane is linear at all the given temperatures. The mean ionic radii for thiobarbiturate ions, being in the region of 2.10-2.70 A°, slightly increases with dioxane percentages. The values of Δ G°, Δ H° and Δ S° have been evaluated. The effect of temperature as well as medium effect are briefly discussed. Source

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