Reaction pathways and kinetics for tetra-alanine in hot, compressed liquid water

James D. Sheehan, Ashwin Abraham, Phillip E. Savage

Research output: Contribution to journalArticlepeer-review

5 Scopus citations


Proteins are abundant biochemical components of microalgae and food wastes that can be used as feedstocks for producing renewable bio-crude oils and value-added chemicals. We elucidated the reaction pathways of a model peptide, tetra-alanine, in hot, compressed liquid water and examined the effects of pH, temperature, and time. We developed a chemical kinetic model that incorporated pH effects and estimated rate parameters from the experimental data. pH influenced the dissociation states of tetra-alanine and the selectivity of reactions. Zwitterionic tetra-alanine predominately formed di-alanine and alanine anhydride as primary products. Anionic tetra-alanine preferentially underwent hydrolysis into tri-alanine, di-alanine, and alanine. The kinetic model provided an excellent correlation to the experimental data. Highly alkaline conditions mitigated yields of alanine anhydride, a N- and O-containing heterocycle representative of compounds that undesirably partition into bio-crude oils. Accordingly, highly alkaline conditions may offer processing conditions for lessening the heteroatom content of bio-crude oils.

Original languageEnglish (US)
Pages (from-to)1237-1252
Number of pages16
JournalReaction Chemistry and Engineering
Issue number7
StatePublished - Jul 2019

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Chemistry (miscellaneous)
  • Chemical Engineering (miscellaneous)
  • Process Chemistry and Technology
  • Fluid Flow and Transfer Processes


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