Accession Number:

ADA625266

Title:

Adsorption of 2 Chloroethyl Ethyl Sulfide on Silica: Binding Mechanism and Energy of a Bifunctional Hydrogen-Bond Acceptor at the Gas Surface Interface

Descriptive Note:

Journal article

Corporate Author:

VIRGINIA POLYTECHNIC INST AND STATE UNIV BLACKSBURG DEPT OF CHEMISTRY

Report Date:

2014-11-19

Pagination or Media Count:

11.0

Abstract:

This work investigates the fundamental nature of sulfur mustard surface adsorption by characterizing interfacial hydrogen bonding and other intermolecular forces for the surrogate molecule simulant 2-chloroethyl ethyl sulfide 2-CEES. Adsorption at the surface of amorphous silica is the focus of this work because of silica s low chemical reactivity, well-known properties, and abundance in the environment. 2-CEES has two polar functional groups, the chloro and thioether moieties, available to accept hydrogen bonds from free surface silanol groups. Diethyl sulfide and chlorobutane are also investigated to independently assess the role of the chloro and thioester functionalities in the overall adsorption mechanism and to explore the interplay between the charge transfer and electrostatic contributions to total hydrogen-bond strength. Our approach utilizes infrared spectroscopy to study specific surface molecule interactions and temperature-programmed desorption to measure the activation energy for desorption of adsorbed molecules. Our results indicate that 2-CEES adsorbs to silica by hydrogen bonding through either the chloro or thioether moieties but is unable to form a more stable configuration in which both polar groups interact simultaneously with adjacent silanol groups. The activation energy for desorption of 2-CEES is nearly 43 kJmol, driven by both strong hydrogen bonding and other non-bonding interactions. A systematic study of chloroalkanes reveals that each methylene group contributes approximately 5 8 kJmol to the overall desorption energy.

Subject Categories:

  • Physical Chemistry
  • Chemical, Biological and Radiological Warfare
  • Electricity and Magnetism

Distribution Statement:

APPROVED FOR PUBLIC RELEASE