22 AprEnvironmental Science & Engineering SeminarFries “on-water” & Understanding Hydrophobic Interactions between Rigid Macroscopic Surfaces Across Various Protic Solvents
Fries “on-water” & Understanding Hydrophobic Interactions between Rigid Macroscopic Surfaces Across Various Protic Solvents
  • Professor Himanshu Mishra & Sreekiran Pillai
  • KAUST
  • Sunday, April 22, 2018
  • 04:00 PM - 05:00 PM
  • Auditorium between Bldg 4 & 5 - Level 0
2018-04-22T16:002018-04-22T17:00Asia/RiyadhFries “on-water” & Understanding Hydrophobic Interactions between Rigid Macroscopic Surfaces Across Various Protic SolventsAuditorium between Bldg 4 & 5 - Level 0


Presenter:
Prof. Himanshu Mishra
Title: Fries “on-water”


Abstract:
Fries rearrangements entail the conversion of phenolic esters into hydroxyaryl ketones—key intermediates in pharmaceuticals, cosmetics, and flavors and fragrance industries—through Lewis acids, such as HF, AlCl3, BF3, and SnCl4 [1] [2-5]. However, the challenges associated with the separation of reaction products, waste disposal, and health and safety due to the application the Lewis acids necessitate greener alternatives[6]. In response, we will describe the first catalyst-free Fries rearrangement of phenyl acetate (PA) in aqueous emulsions driven by interfacial phenomena.


Bio:
Professor Himanshu Mishra directs Interfacial Lab (iLab), comprising of engineers, chemists, and theoreticians, at WDRC. His areas of scientific interest include measurement of chemical reactions and surface forces at the interfaces of water with hydrophobic media, such as air and oils. His finish-time for KAUST’s first mini-triathlon event – 400 m swim, 20 km bike, and 5 km run – was 1:19:44.


Presenter: Sreekiran Pillai
Title: Understanding Hydrophobic Interactions between Rigid Macroscopic Surfaces Across Various Protic Solvents


Abstract:
Engineers routinely characterize hydrophobic surfaces by measuring contact angles, θ_r, of water droplets on them – if θ_r>〖90〗^°, surfaces are classified as hydrophobic. Despite this simple assessment, the fundamental nature of the hydrophobic interaction, defined as the attractive force experienced by two hydrophobic surfaces across water, remains unclear. Specifically, molecular-scale insights into the distance-dependence of the hydrophobic interaction and, the effects of adsorption of ions and evolution of hydrogen bonded percolation networks at water-hydrophobic interfaces are not entirely clear. Detergency and self-assembly process in air, oils and perflurocarbons are common examples of hydrophobic interactions. However, despite its ubiquitosness, mechanistic insights into hydrophobic interactions between extended surfaces remain elusive. To resolve those issues we quantified hydrophobic interactions between molecularly-smooth mica surfaces terminated with perfluorodecyltrichlorosilane (FDTS) molecules in a variety of aqueous solutions, including 10 mM KCl water and heavy water, methanol, ethanol, and isopropanol, and 10 mM aqueous solutions of KBr, KI, KClO4, KPF6 using the Surface Force Apparatus (SFA). Intriguingly, we found that the hydrophobic interaction was stronger in light water compared to heavy water. This difference in hydrophobic interaction comes up when most of the physical properties of light water and heavy water are the same. My seminar will be a brief talk about the SFA technique used for the force measurement studies followed by the results and backed up by molecular dynamic simulations.


Bio:
Sreekiran Raveendran Pillai received his M.Tech in Chemical Engineering from Indian Institute of Technology (I.I.T) Bombay in 2014 with an All India Rank of 148, where he worked under Prof. Sarika Mehra and Prof. Rama Govindarajan. He joined Interfacial Lab in WDRC during the Fall of 2015. Currently he is pursuing his PhD in the department of Environmental Engineering under the supervision of Prof Himanshu Mishra. His research interest includes surface engineering, hydrophobic interactions and interfacial engineering.

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