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Please use this identifier to cite or link to this item: http://hdl.handle.net/123456789/344

Title: A Molecular Picture of Diffusion Controlled Reaction: Role of Microviscosity and Hydration on Hydrolysis of Benzoyl Chloride at a Polymer Hydration Region
Authors: Verma, Pramod Kumar
Mitra, Rajib Kumar
Pal, Samir Kumar
Issue Date: 2009
Publisher: Langmuir
Citation: P. K. Verma, R. K. Mitra and S. K. Pal, A Molecular Picture of Diffusion Controlled Reaction: Role of Microviscosity and Hydration on Hydrolysis of Benzoyl Chloride at a Polymer Hydration Region, Langmuir, 2009, 25, 11336
Abstract: In this study, we have attempted to explore the molecular mechanism associated with a diffusion controlled reaction at a polymer hydration region by monitoring temperature-dependent solvolysis reaction of benzoyl chloride (BzCl) in water-poly(ethylene glycol) mixture at low water concentration. BzCl being highly hydrophobic resides in the vicinity of the PEG surface and the reaction takes place at the interface. Temperature-dependent solvolysis allows one to estimate the overall Arrhenius type activation energy barrier associated with the reaction. To understand the relative contribution of hydration and diffusive motion on the overall activation energy we studied the temperature-dependent picosecond-resolved solvation dynamics using a fluorescence probe Coumarin 500 (C500). The observed acceleration of solvation dynamics with temperature finds its origin in temperature-induced transition of bound to free type interfacial water molecules near the PEG surface. Temperature-dependent acoustic and densimetric studies also support this phenomenon. The temperature-induced enhancement of the local viscosity experienced by the probe, which is calculated from the rotational anisotropy studies, furnishes the activation barrier for microvisoscity as applicable to the Kramers model. The activation energy barriers estimated from the temperature-dependent solvation dynamics and microviscosity studies are correlated with that obtained from the solvolysis reaction.
URI: http://hdl.handle.net/123456789/344
Appears in Collections:2009

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