A density functional theory model of mechanically activated silyl ester hydrolysis.
作者： Michael F. Pill , Sebastian W. Schmidt , Martin K. Beyer , Hauke Clausen-Schaumann , Alfred Kersch
DOI: 10.1063/1.4862827
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摘要: To elucidate the mechanism of mechanically activated dissociation chemical bonds between carboxymethylated amylose (CMA) and silane functionalized silicon dioxide, we have investigated kinetics connecting CMA to oxide surfaces with density functional calculations including effects force, solvent polarizability, pH. We determined activation energies, pre-exponential factors, reaction rate constants candidate reactions. The weakest bond was found be silyl ester alkoxy oxygen atom. Under acidic conditions, spontaneous proton addition occurs close such that neutral reactions become insignificant. Upon at most favored position, energy for hydrolysis becomes 31 kJ mol(-1), which agrees very well experimental observation. Heterolytic scission in protonated molecule has a much higher energy. experimentally observed bi-exponential rupture can explained by different side groups attached atom ester. fact lead provides an opportunity deliberately modify tune kinetic parameters esters. (C) 2014 AIP Publishing LLC.
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