9615

8870

كارشناسي ارشد

شيمي فيزيك

اصفهان: دانشگاه صنعتي اصفهان، دانشكده شيمي

1393

[پانزده]،86ص.: مصور،جدول،نمودار

ص.ع.به فارسي و انگليسي

بيژن نجفي

حميد مصدقي نقندر

93/12/17

يوسف غائب، حسين فرخ پور

شيمي

ID8870

Molecular dynamics simulations of water and ethylene glycol systems and Study the Diffusion coefficient and hydrogen bonding using the OPLS force field with modified parameter Behrouz Rahimpour e mail rahimpour behrouz@gmail com December 02 2014 Department of Chemistry Isfahan University of Technology Isfahan 84156 83111 IranLanguage Farsi Degree M Sc aSupervisor Prof Bijan Najafi E Mail najafi@cc iut ac irAdvisor Assist Prof Hamid Mosaddeghi Noghandar E Mail h mosaddeghi@gmail comDepartment Graduate Program Coordinator Assist Prof Alireaza Najafia a Department of Chemistry Isfahan University of Technology Isfahan 84156 83111 Iran Abstract Liquid ethylene glycol EG is best known as anti freeze protection in cooling heatingsystems as well as in de icing solutions for vehicles and runways of airports It serves asan ingredient of electrolytic capacitors printer s inks and is also a raw material for theproduction of explosives and synthetic waxes EG is a sweetly tasting odorless liquid and itis toxic if swallowed in large amounts EG and EG water mixtures are used as a mediawith variable viscosity in experimental studies of the solvent dynamics effect onelectrochemical reactions In this thesis the method of Molecular Dynamic MD simulations is used to study various mixtures of ethylene glycol and water mixtures Antifreeze The simulations are carried out with at least 1000 atoms mostly at 298 K andsome other temperatures The pressure and time step is 1 0 atm 0 001 ps respectively Thepurpose of these simulations is the study of some important quantities such as density mean square displacement MSD diffusion coefficient radial distribution function excessparameters hydrogen bonds and activation energyof EG water mixtures with differentmole fractions Firstly the simulation is performed in the NPT isobaric isothermal ensemble at 298 K using DL POLY 2 18 during 1 ns step 1000000 to equilibrated thesystems and then in NVE micro canonical to obtain the desired quantities The secondpart of the thesis is about the calculation of the number of hydrogen bonds in pure water pure ethanol and EG water with different mole fractions As it was observedexperimentally the minimum mixture volume and enthalpy occurs at about mole fraction of0 4 and also the minimum number of hydrogen bonds also belongs to this mole fraction Inthis thesis we reached to this conclusion that this minimum of volume and enthalpy at thismole fraction depends on the strength of hydrogen bonds rather than the number of suchbonds Keywords Molecular dynamics simulation Ethylene glycol Density Radialdistribution function Excess quantities Excess molar volume Excess molar enthalpy number of Hydrogen bond

بيژن نجفي

حميد مصدقي نقندر

يوسف غائب، حسين فرخ پور