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

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

Research output: Contribution to journalArticle

Abstract

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
Volume4
Issue number7
DOIs
StatePublished - Jul 1 2019

Fingerprint

Alanine
Crude oil
Kinetics
Water
Liquids
pH effects
Petroleum
Reaction kinetics
Feedstocks
Peptides
Hydrolysis
Anhydrides
Proteins
Processing
Temperature

All Science Journal Classification (ASJC) codes

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

Cite this

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abstract = "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.",
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Reaction pathways and kinetics for tetra-alanine in hot, compressed liquid water. / Sheehan, James D.; Abraham, Ashwin; Savage, Phillip E.

In: Reaction Chemistry and Engineering, Vol. 4, No. 7, 01.07.2019, p. 1237-1252.

Research output: Contribution to journalArticle

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