Heat of hydrolysis of phosphorus pentachloride, and heat of formation of aqueous orthophosphoric acid

1968 ◽  
Vol 64 ◽  
pp. 3232 ◽  
Author(s):  
G. I. Birley ◽  
H. A. Skinner
Keyword(s):  
Orthophosphoric Acid ◽  
Phosphorus Pentachloride ◽  
Heat Of Formation ◽  
Hydrolysis Of ◽  
Heat Of Hydrolysis

The heat of hydrolysis of boron tribromide

1955 ◽  
Vol 51 ◽  
pp. 19 ◽  
Author(s):  
H. A. Skinner ◽  
N. B. Smith
Keyword(s):  
Boron Tribromide ◽  
Hydrolysis Of ◽  
Heat Of Hydrolysis

scholarly journals Towards a Non-Biased Formaldehyde Quantification in Leather: New Derivatization Conditions before HPLC Analysis of 2,4-Dinitrophenylhydrazine Derivatives

Molecules ◽  
2020 ◽  
Vol 25 (23) ◽  
pp. 5765
Author(s):  
Caroline Bourgeois ◽  
Nicolas Blanc ◽  
Jean-Claude Cannot ◽  
Claire Demesmay
Keyword(s):  
Hplc Analysis ◽  
Orthophosphoric Acid ◽  
Reversed Phase ◽  
Precolumn Derivatization ◽  
Reversed Phase Liquid Chromatography ◽  
Formaldehyde Content ◽  
Buffer Solutions ◽  
Phase Liquid ◽  
Acidic Conditions ◽  
Hydrolysis Of

In leathers, formaldehyde is currently analyzed according to EN ISO 17226-1 standard, by reversed phase liquid chromatography after off-line precolumn derivatization with 2,4 dinitrophenylhydrazine (DNPH) in strong acidic conditions. We first demonstrate that this standard is not adapted to leather retanned with resins likely to release formaldehyde by hydrolysis. Indeed, formaldehyde content may be largely overestimated due to concomitant resin hydrolysis (in harsh acidic conditions) that releases formaldehyde during the derivatization step and during the waiting time on autosampler before analysis. Therefore, we thoroughly studied the derivatization step in order to propose new derivatization conditions. Replacing orthophosphoric acid by less acidic buffer solutions is not enough to avoid hydrolysis. A derivatization without adding acid is realized by solubilizing DNPH in acetonitrile instead of orthophosphoric acid. These conditions lead to a complete derivatization of formaldehyde in 3 h at 50 °C (in a water bath) while avoiding the hydrolysis of co-extracted dicyandiamide and melamine resins. The as-obtained leather extracts are stable over time. Formaldehyde contents found with this method agree with the formaldehyde content measured immediately at the end of derivatization reaction in standard conditions or with formaldehyde content measured by a home-designed flow injection analysis with acetylacetone online derivatization and UV detection.

scholarly journals The Heat of Hydrolysis of i-Propenyl Acetate and m-Cresyl Acetate and the Heat of Enolization of Acetone.

1957 ◽  
Vol 11 ◽  
pp. 1757-1760 ◽  
Author(s):  
S. Sunner ◽  
Johan J. Lothe ◽  
K. Lunde ◽  
J. Schliack ◽  
L. Reio
Keyword(s):  
Hydrolysis Of ◽  
Heat Of Hydrolysis

Heat of hydrolysis of trimetaphosphate

1953 ◽  
Vol 12 (1-2) ◽  
pp. 121-127 ◽  
Author(s):  
Otto Meyerhof ◽  
Romas Shatas ◽  
Ann Kaplan
Keyword(s):  
Hydrolysis Of ◽  
Heat Of Hydrolysis

The Effect of Ionic Strength on the Heat of Hydrolysis of Benzoyl-L-argininamide1

1956 ◽  
Vol 78 (7) ◽  
pp. 1349-1352 ◽  
Author(s):  
Waldie W. Forrest ◽  
Herbert Gutfreund ◽  
Julian M. Sturtevant
Keyword(s):  
Ionic Strength ◽  
Hydrolysis Of ◽  
Heat Of Hydrolysis

The tetrahedral intermediate from the hydration of N-methylformanilide

1993 ◽  
Vol 71 (12) ◽  
pp. 2109-2122 ◽  
Author(s):  
J. Peter Guthrie ◽  
Jonathan Barker ◽  
Patricia A. Cullimore ◽  
Jinqiao Lu ◽  
David C. Pike
Keyword(s):  
Aqueous Solution ◽  
Free Energy ◽  
Dimethyl Acetal ◽  
Heat Of Formation ◽  
Basic Solution ◽  
Tetrahedral Intermediate ◽  
Rate Determining Step ◽  
Free Energy Of Formation ◽  
Hydrolysis Of ◽  
Energy Of Formation

Heats of hydrolysis of N-methylformanilide dimethyl acetal have been measured in basic solution. The heat of formation of N-methylformanilide was obtained by determining the equilibrium constant in aqueous solution for its formation from formic acid and N-methylaniline as a function of temperature:[Formula: see text]. These data permit the calculation of the heat of formation of N-methylformanilide dimethyl acetal, [Formula: see text]. The free energy of formation of the tetrahedral intermediate in the hydrolysis of N-methylformanilide was calculated by methods we have previously reported. Consideration of the energetics of the intermediates and the known rates of reaction leads to the conclusion that the rate-determining step for alkaline hydrolysis is cleavage of the C—N bond.

scholarly journals Synthesis of malonyldi(1,2,4-triazole), the study of the kinetic and thermodynamic features of its hydrolysis and prediction of biological activity

2019 ◽  
Vol 57 (1) ◽  
pp. 41-49
Author(s):  
Pyotr P. Purygin ◽  
◽  
Maria V. Evstegneeva ◽  
Roman V. Shafigulin ◽  
Yury P. Zarubin ◽  
...  
Keyword(s):  
Biological Activity ◽  
Water System ◽  
Thermodynamic Characteristics ◽  
Heat Of Formation ◽  
Step Method ◽  
Stable Conformer ◽  
Anti Oxidant ◽  
Layer Chromatography ◽  
Kinetics Of ◽  
Hydrolysis Of

This article describes a two-step method for the synthesis of malondyl (1,2,4-triazole) (1,3-di (1H-1,2,4-triazol-1-yl)propane-1,3-dione) of 1,2,4-triazole through 1-trimethylsilyl-1,2,4-triazole, followed by reaction with malonyl chloride; the yield of the final product is 85%. The kinetics of hydrolysis of malonyldi(1,2,4-triazole) in the acetonitrile – water system (9:1) at 25 °C and 35 °C was studied, and the activation energy of the hydrolysis of malonyldi(1,2,4-triazole). To study the thermodynamic features of the reactions of obtaining this compound in the Spartan’14 1.1.4 program, a number of thermodynamic characteristics were calculated, which determine the spontaneous and exothermic nature of the process. For the molecule malonyldi(1,2,4-triazole), the most and least stable conformers were found in the program Molecular Operating Environment 2009.10, for which the surfaces of nucleophilic susceptibility were calculated in the program SCIGRESS Modeling 3.1.4. It was shown that the most stable conformer of the malonyldi(1,2,4-triazole) molecule should have the highest reactivity in reactions with different nucleophiles and the lowest value of the heat of formation. In this case, the nucleophilic susceptibility of carbonyl carbon atoms is different, despite the symmetry of the structure of the molecules malonyldi(1,2,4-triazole), which suggests a stepwise interaction of malonyldi(1,2,4-triazole) with nucleophiles. The structure of malonyldi(1,2,4-triazole) was confirmed by IR, 1H NMR spectroscopy, individuality – by thin-layer chromatography. The proposed mechanism for the hydrolysis of malonyldi(1,2,4-triazole) is described. The program PASS Professional 2007 predicted the most likely types of biological activity of the studied compounds. The most significant types of biological activity are anti-diabetic, anti-ulcer, anti-ischemic, anti-oxidant. The obtained data allow us to choose the optimal conditions for the synthesis of malonyldi(1,2,4-triazole) and to conclude that it is highly hydrolytically stable in an aqueous acetonitrile medium.

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