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Reactions at the solid-liquid interface: surface-controlled dissolution of solid particles. The dissolution of
Claire L Forryan1, Oleksiy V Klymenko, Colin M Brennan
1Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom.
The Journal of Physical Chemistry. B
|July 21, 2006
Summary
This study models surface-controlled solid particle dissolution, specifically potassium bicarbonate in DMF. Experimental results reveal dissolution kinetics shift from homogeneous reaction to dissolution-rate control over time.
Area of Science:
- Physical Chemistry
- Chemical Engineering
- Materials Science
Background:
- Understanding solid particle dissolution is crucial for chemical processes.
- Particle size distribution significantly impacts dissolution kinetics.
- Surface-controlled dissolution models are essential for predicting material behavior.
Purpose of the Study:
- To develop and apply a mathematical model for surface-controlled dissolution of solid particles.
- To investigate the dissolution kinetics of potassium bicarbonate (KHCO3) in dimethylformamide (DMF) under varying particle size distributions.
- To experimentally validate the dissolution model using indirect monitoring techniques.
Main Methods:
- Mathematical modeling of surface-controlled dissolution.
- Experimental study of KHCO3 dissolution in DMF at elevated temperatures.
- Indirect kinetic monitoring via electrochemical detection of 2-cyanophenol loss and UV-Vis spectroscopy of 2-cyanophenolate anion formation.
Main Results:
- Kinetics transition from homogeneous reaction-controlled to dissolution-rate-controlled over time.
- Model accurately describes dissolution for monodispersed, two-size, and Gaussian particle distributions.
- Determined KHCO3 dissolution rate constant (k) as (1.1 ± 0.3) x 10⁻⁸ mol cm⁻² s⁻¹ at 100°C.
- Calculated activation energy for dissolution as 34.4 ± 0.4 kJ mol⁻¹ (60-100°C).
Conclusions:
- The developed model effectively captures surface-controlled dissolution phenomena.
- Experimental data supports the model's predictions across different particle size distributions.
- Quantified key kinetic parameters for KHCO3 dissolution in DMF, providing valuable data for process optimization.
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