Gasification Characteristics of Aminobutyric Acid and Serine as Model Compounds of Proteins under Supercritical Water Conditions

The gasification characteristics of aminobutyric acid and serine were determined under supercritical water conditions using a tubular flow reactor. A 1.0 wt% aqueous solution of these two amino acids was gasified at temperatures ranging from 400 to 650 degrees C and a pressure of 25 MPa with residence time of 86-222 s. The products were identified and quantified by gas chromatography, and the total organic carbon in the aqueous phase was also determined. The gasification characteristics were compared with those of glycine and alanine. The carbon gasification efficiency increased with higher reaction temperature. The gasification rate followed first order kinetics and was explained well by the Arrhenius equation. The gasification rate of aminobutyric acid was similar to that of glycine and alanine but the gasification rate of serine is faster. The oxygen in the hydroxyl group of serine is highly electronegative, so serine is more reactive than glycine and alanine.