Mechanistic modeling of hydrolysis and esterification for biofuel processes

Shujauddin Changi, Tanawan Pinnarat, Phillip E. Savage

Research output: Contribution to journalArticlepeer-review

19 Scopus citations

Abstract

We have elucidated the mechanism for ethyl oleate hydrolysis in high temperature water and its reverse reaction, oleic acid esterification in near- and supercritical ethanol in the absence of any other added compounds. Both reactions are acid catalyzed. H+ (from dissociation of water and oleic acid) and oleic acid serve as catalysts for hydrolysis and H+ alone is the catalyst for esterification. The rate equation arising from the proposed mechanism provided a good fit of experimental conversion data for both hydrolysis and esterification. The rate equation accurately predicted the influence of pH on hydrolysis for acidic and near-neutral conditions. The mechanistic model exhibits the ability to make quantitatively accurate predictions within and outside the original parameter space, especially for a multicomponent system. Sensitivity analysis shows that the values of the dissociation constant of oleic acid in ethanol, water, and ethanol-water systems strongly influence the predicted conversions. There is a need for experimental measurement of pKa for fatty acids in both water and alcohols at elevated temperatures.

Original languageEnglish (US)
Pages (from-to)12471-12478
Number of pages8
JournalIndustrial and Engineering Chemistry Research
Volume50
Issue number22
DOIs
StatePublished - Nov 16 2011

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Chemical Engineering(all)
  • Industrial and Manufacturing Engineering

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