title: Investigations on the structure of dimethyl sulfoxide and acetone in aqueous solution.
abstract: Aqueous solutions of dimethyl sulfoxide (DMSO) and acetone have been investigated using neutron diffraction augmented with isotopic substitution and empirical potential structure refinement computer simulations. Each solute has been measured at two concentrations-1:20 and 1:2 solute:water mole ratios. At both concentrations for each solute, the tetrahedral hydrogen bonding network of water is largely unperturbed, though the total water molecule coordination number is reduced in the higher 1:2 concentrations. With higher concentrations of acetone, water tends to segregate into clusters, while in higher concentrations of DMSO the present study reconfirms that the structure of the liquid is dominated by DMSO-water interactions. This result may have implications for the highly nonideal behavior observed in the thermodynamic functions for 1:2 DMSO-water solutions.
authors.affiliation: Spallation Neutron Source and Center for Molecular Biophysics, Oak Ridge National Laboratory, PO Box 2008, Oak Ridge, Tennessee 37831-6475, USA. mclainse@ornl.gov
authors.forename: Sylvia E
authors.initials: SE
authors.lastname: McLain
authors.forename: Alan K
authors.initials: AK
authors.lastname: Soper
authors.forename: Alenka
authors.initials: A
authors.lastname: Luzar
mesh_terms: D000096:Acetone / Q000737:chemistry*; D002627:Chemistry, Physical / Q000379:methods*; D003198:Computer Simulation; D017666:Deuterium Oxide / Q000737:chemistry; D004121:Dimethyl Sulfoxide / Q000737:chemistry*; D006860:Hydrogen Bonding; D008968:Molecular Conformation; D011725:Pyridines / Q000737:chemistry; D013053:Spectrophotometry / Q000379:methods; D013499:Surface Properties; D013696:Temperature; D014867:Water / Q000737:chemistry*
chemical_list: D011725:Pyridines; D014867:Water; D000096:Acetone; D017666:Deuterium Oxide; C023666:pyridine; D004121:Dimethyl Sulfoxide