scholarly journals Heat of reaction of diborane with water and the heat of formation of boric oxide

1959 ◽  
Vol 62 (1) ◽  
pp. 43 ◽  
Author(s):  
E.J. Prosen ◽  
W.H. Johnson ◽  
F.Y. Pergiel
Keyword(s):  
Heat Of Formation ◽  
Boric Oxide ◽  
Heat Of Reaction

Ketene. III. Heat of Formation and Heat of Reaction with Alcohols

1934 ◽  
Vol 56 (11) ◽  
pp. 2268-2270 ◽  
Author(s):  
F. O. Rice ◽  
Joseph Greenberg
Keyword(s):  
Heat Of Formation ◽  
Heat Of Reaction

Thermodynamics of methanesulfonic acid revisited

2000 ◽  
Vol 78 (10) ◽  
pp. 1295-1298 ◽  
Author(s):  
J Peter Guthrie ◽  
Roger T Gallant
Keyword(s):  
Methanesulfonic Acid ◽  
Heat Of Formation ◽  
Methyl Methanesulfonate ◽  
Thermodynamic Quantities ◽  
Heat Of Reaction ◽  
Reaction Conditions ◽  
Free Energy Of Formation ◽  
Sulfite Ion ◽  
Energy Of Formation

Recently we reported a study of the thermodynamics of methanesulfonic acid and some of its derivatives. The foundation of these results was a measurement of the heat of reaction of S-methyl thioacetate with aq sodium hypochlorite, leading to methanesulfonic acid. We have reinvestigated this reaction and discovered that contrary to the initial stoichiometry experiments, the stoichiometry under the reaction conditions is not as was believed and that the heat of reaction observed was spuriously high. We have found a new reaction, that of sulfite ion with methyl methanesulfonate, which does allow a clean determination of the heat of formation of methanesulfonic acid. Revised thermodynamic quantities for methanesulfonic acid, methanesulfonyl chloride, and methyl methanesulfonate are reported here.Key words: sulfonic acid, heat of reaction, free energy of formation, SN2 reaction.

The Heat of Formation of Boric Oxide

1946 ◽  
Vol 68 (3) ◽  
pp. 530-530 ◽  
Author(s):  
B. J. Todd ◽  
R. R. Miller
Keyword(s):  
Heat Of Formation ◽  
Boric Oxide

scholarly journals Synthetic approach of ternary magnesium niobate (Mg–Nb–O) compounds

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Md. Wasikur Rahman
Keyword(s):  
Solid State ◽  
Rietveld Method ◽  
Heat Of Formation ◽  
Ex Situ ◽  
Solid State Reactions ◽  
Effect Of Temperature ◽  
Synthetic Approach ◽  
Heat Of Reaction ◽  
Magnesium Niobate

AbstractMagnesium based niobium oxides (Mg–Nb–O) were prepared by solid-state reactions owing to understand the function of transition metal oxides as promoters/catalysts for practical application. Magnesium niobate (Mg3Nb6O11) was synthesized for the first time in nearly pure form reported in this context. MgNb2O6 and Mg4Nb2O9 were prepared in oxidizing conditions; on the contrary, Mg3Nb6O11 preferred reducing environment. Stoichiometric mixtures of the precursor materials MgO, Nb2O5 and/or metallic Nb were annealed for the syntheses which revealed the effect of temperature on phase formation, reaction kinetics and heat of reaction. The products were examined by ex-situ, in-situ X-ray diffraction (XRD) and differential scanning calorimetry (DSC). Crystallographic parameters of various binary and ternary compounds (Mg/Nb/O) formed in different calcination conditions, were extracted by Rietveld method. In-situ experiment results in single step reaction for the MgNb2O6 synthesis and the heat of formation of the solid-state reaction obtained to be minimum (93 kJ/mol). In contrast, the formation of Mg4Nb2O9 and Mg3Nb6O11 compounds towards pure phases rather complicated due to multistep reactions and corresponding heat of formation were estimated to be 140 and 190 kJ/mol. Experimental results have been discussed based on kinetic and thermodynamic constrains.

scholarly journals Synthetic Approach of Ternary Magnesium Niobate(Mg–Nb–O) Compounds

2021 ◽  
Author(s):  
M. W. Rahman
Keyword(s):  
Solid State ◽  
Rietveld Method ◽  
Heat Of Formation ◽  
Ex Situ ◽  
Solid State Reactions ◽  
Effect Of Temperature ◽  
Synthetic Approach ◽  
Heat Of Reaction ◽  
Magnesium Niobate

Abstract Magnesium based niobium oxides (Mg–Nb–O) were prepared by solid–state reactions owing to understand the function of transition metal oxides as promoters/catalysts for practical application. Magnesium niobate (Mg3Nb6O11) was synthesized for the first time in nearly pure form reported in this context. MgNb2O6 and Mg4Nb2O9 were prepared in oxidizing conditions; on the contrary, Mg3Nb6O11 preferred reducing environment. Stoichiometric mixtures of the precursor materials MgO, Nb2O5 and/or metallic Nb were annealed for the syntheses which revealed the effect of temperature on phase formation, reaction kinetics and heat of reaction. The products were examined by ex–situ, in–situ X–ray diffraction (XRD) and differential scanning calorimetry (DSC). Crystallographic parameters of various binary and ternary compounds (Mg/Nb/O) formed in different calcination conditions, were extracted by Rietveld method. In–situ experiment results in single step reaction for the MgNb2O6 synthesis and the heat of formation of the solid–state reaction obtained to be minimum (93 kJ/mol). In contrast, the formation of Mg4Nb2O9 and Mg3Nb6O11 compounds towards pure phases rather complicated due to multistep reactions and corresponding heat of formation were estimated to be 140 and 190 kJ/mol. Experimental results have been discussed based on kinetic and thermodynamic constrains.

Thermodynamics of methanesulfonic acid, methanesulfonyl chloride, and methyl methanesulfonate

1998 ◽  
Vol 76 (6) ◽  
pp. 929-936 ◽  
Author(s):  
J Peter Guthrie ◽  
Allan R Stein ◽  
Anthony P Huntington
Keyword(s):  
Aqueous Solution ◽  
Methanesulfonic Acid ◽  
Heat Of Formation ◽  
Methyl Methanesulfonate ◽  
Molecular Orbital Calculations ◽  
Heat Of Reaction ◽  
Free Energies ◽  
Methanesulfonyl Chloride ◽  
Free Energy Of Formation ◽  
Energy Of Formation

The heat of formation of liquid methanesulfonic acid, -178.09 ± 1.48, was determined by measuring the heat of reaction of methyl thiolacetate with aqueous hypochlorite solution to give aqueous methanesulfonate and acetate. The heats of formation of liquid methanesulfonyl chloride, -126.91 ± 1.54, and methyl methanesulfonate, -164.34 ± 1.58, were determined by measuring the heats of reaction of methanesulfonyl chloride with water or methanol in the presence of a suitable basic catalyst. Heats of vaporization (based on vapor-pressure data), entropies (based on ab initio molecular orbital calculations), and free energies of transfer from gas phase to aqueous solution were calculated leading to values for the free energies of formation in aqueous solution. The free energies of formation so determined were methanesulfonic acid, -151.72 ± 2.68, methanesulfonyl chloride, -101.29 ± 1.96, and methyl methanesulfonate, -127.28 ± 2.08. From these values the free energies of hydrolysis (leading to unionized methanesulfonic acid) are methanesulfonyl chloride, -25.11 ± 3.04, and methyl methanesulfonate, -9.90 ± 2.48.Key words: sulfonic acids, heat of formation, free energy of formation, hydrolysis.

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