The effects of molecular association on mutual diffusion

Pao Yue-kong Library Electronic Theses Database

The effects of molecular association on mutual diffusion

 

Author: Chen, Nong
Title: The effects of molecular association on mutual diffusion
Degree: M.Phil.
Year: 1998
Subject: Molecular association
Molecular dynamics
Diffusion
Molecules
Hong Kong Polytechnic University -- Dissertations
Department: Dept. of Applied Biology and Chemical Technology
Pages: vii, 79 leaves : ill. ; 30 cm
Language: English
InnoPac Record: http://library.polyu.edu.hk/record=b1442207
URI: http://theses.lib.polyu.edu.hk/handle/200/3260
Abstract: Limiting mutual diffusion coefficients (D12) of a series of pseudoplannar polar compounds in various organic solvents at 298.2K and in ethanol at different temperatures ranging from 283.2K to 328.2K were measured by using the chromatographic peak-broadening method. The data were compared with those of the nonassociated pseudoplanar molecules of similar size and shape. Solutes capable of strong solute-solvent interactions in this work were found to diffuse slower than the nonassociated counterparts. The effects of molecular association on diffusion as well as the solvation numbers were determined for the polar solutes. It was found that the effects of hydrogen bonding and the solvation numbers are approximately equal for solutes containing the same polar group that forms hydrogen bonds with the solvent molecules. The effects as well as the solvation numbers are nonetheless different for different functional groups, with -OH> -NH2> -SH> -C(O)- in general. For both the associated and nonassociated solutes studied, there exists a linear relationship between the reciprocal of the diffusion coefficients and the molecular volume (V) of the solutes in a given solvent at constant temperature. It appears that the diffusivities are also insensitive to the mass of the nonassociated and associated solute molecules. The temperature dependence of the diffusion coefficients was also studied, and a linear correlation between ln D12 and 1/T was found for all the aromatic solutes studied. From the plots of ln D12 against 1/T, activation energies of different functional solutes were calculated. The activation energies for the solutes studied have the following order: phenols > aromatic amines > phenones > aromatic ethers > nonassociated solutes > 2-naphthalenethiol.

Files in this item

Files Size Format
b14422074.pdf 2.346Mb PDF
Copyright Undertaking
As a bona fide Library user, I declare that:
  1. I will abide by the rules and legal ordinances governing copyright regarding the use of the Database.
  2. I will use the Database for the purpose of my research or private study only and not for circulation or further reproduction or any other purpose.
  3. I agree to indemnify and hold the University harmless from and against any loss, damage, cost, liability or expenses arising from copyright infringement or unauthorized usage.
By downloading any item(s) listed above, you acknowledge that you have read and understood the copyright undertaking as stated above, and agree to be bound by all of its terms.

     

Quick Search

Browse

More Information