Hammett Parameter and Molecular-Modeling Correlations of Substituent Effects on Esterification Kinetics

2010 ◽  
Vol 87 (8) ◽  
pp. 845-847 ◽  
Author(s):  
Jeremy B. Smith ◽  
Houston Byrd ◽  
Stephen E. O’Donnell ◽  
Will Davis
Keyword(s):  
Molecular Modeling ◽  
Substituent Effects ◽  
Hammett Parameter

Using Cyclic Voltammetry and Molecular Modeling To Determine Substituent Effects in the One-Electron Reduction of Benzoquinones

1998 ◽  
Vol 75 (3) ◽  
pp. 365 ◽  
Author(s):  
Janell E. Heffner ◽  
Jeffrey C. Raber ◽  
Owen A. Moe ◽  
Carl T. Wigal
Keyword(s):  
Cyclic Voltammetry ◽  
Molecular Modeling ◽  
Substituent Effects ◽  
Electron Reduction ◽  
The One

Molecular Modeling of the Interaction of LSD and Other Hallucinogens With 5-HT2 Receptors

1994 ◽  
Author(s):  
Richard B. Westkaemper ◽  
◽  
Richard A. Glennon
Keyword(s):  
Molecular Modeling

The Use of Conformational Restriction and Molecular Modeling Techniques in the Development of Receptor-Specific Opioid Peptide Agonists and Antagonists

1993 ◽  
Author(s):  
Peter W. Schiller ◽  
◽  
Thi M.-D. Nguyen ◽  
Grazyna Weltrowska ◽  
Nga N. Chung ◽  
...  
Keyword(s):  
Molecular Modeling ◽  
Opioid Peptide ◽  
Conformational Restriction ◽  
Modeling Techniques

NMR and molecular modeling: application to wine ageing

1998 ◽  
Vol 95 (2) ◽  
pp. 357-365 ◽  
Author(s):  
C. Saucier ◽  
I. Pianet ◽  
M. Laguerre ◽  
Y. Glories
Keyword(s):  
Molecular Modeling ◽  
Wine Ageing

Kemit : an interactive molecular modeling program based on the PHIGS+ standard

1991 ◽  
Vol 88 ◽  
pp. 2497-2503 ◽  
Author(s):  
DJ Vanderveken ◽  
G Baudoux ◽  
F Durant ◽  
DP Vercauteren
Keyword(s):  
Molecular Modeling

Substituent effects and solvents

1992 ◽  
Vol 89 ◽  
pp. 1567-1571
Author(s):  
O Pytela ◽  
M Ludwig
Keyword(s):  
Substituent Effects

Substituent Effects on the Thermal Decomposition of Phosphate Esters on Ferrous Surfaces

2019 ◽  
Author(s):  
James Ewen ◽  
Carlos Ayestaran Latorre ◽  
Arash Khajeh ◽  
Joshua Moore ◽  
Joseph Remias ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Film Formation ◽  
Substituent Effects ◽  
Vapour Phase ◽  
Industrial Applications ◽  
Phosphate Esters ◽  
Antiwear Additives ◽  
Formation Mechanisms ◽  
Phosphate Ester ◽  
Wide Range

<p>Phosphate esters have a wide range of industrial applications, for example in tribology where they are used as vapour phase lubricants and antiwear additives. To rationally design phosphate esters with improved tribological performance, an atomic-level understanding of their film formation mechanisms is required. One important aspect is the thermal decomposition of phosphate esters on steel surfaces, since this initiates film formation. In this study, ReaxFF molecular dynamics simulations are used to study the thermal decomposition of phosphate esters with different substituents on several ferrous surfaces. On Fe<sub>3</sub>O<sub>4</sub>(001) and α-Fe(110), chemisorption interactions between the phosphate esters and the surfaces occur even at room temperature, and the number of molecule-surface bonds increases as the temperature is increased from 300 to 1000 K. Conversely, on hydroxylated, amorphous Fe<sub>3</sub>O<sub>4</sub>, most of the molecules are physisorbed, even at high temperature. Thermal decomposition rates were much higher on Fe<sub>3</sub>O<sub>4</sub>(001) and particularly α-Fe(110) compared to hydroxylated, amorphous Fe<sub>3</sub>O<sub>4</sub>. This suggests that water passivates ferrous surfaces and inhibits phosphate ester chemisorption, decomposition, and ultimately film formation. On Fe<sub>3</sub>O<sub>4</sub>(001), thermal decomposition proceeds mainly through C-O cleavage (to form surface alkyl and aryl groups) and C-H cleavage (to form surface hydroxyls). The onset temperature for C-O cleavage on Fe<sub>3</sub>O<sub>4</sub>(001) increases in the order: tertiary alkyl < secondary alkyl < primary linear alkyl ≈ primary branched alkyl < aryl. This order is in agreement with experimental observations for the thermal stability of antiwear additives with similar substituents. The results highlight surface and substituent effects on the thermal decomposition of phosphate esters which should be helpful for the design of new molecules with improved performance.</p>

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