Soy protein concentrate was hydrothermally treated at isothermal temperatures of 200, 250, 300, and 350 °C for times up to 60 min to produce a crude bio-oil. Additional product fractions included water-soluble products, gases, and residual solids. We report herein the conversion of protein and gravimetric yields of the different product fractions. The biocrude yield generally increased with both time and temperature as did the yield of gaseous products. The highest biocrude yield was 34%, produced from liquefaction at 350 °C for 60 min. Chemical and physical characterization of the biocrude revealed how its composition and boiling point range changed with reaction time. Finally, we report a reaction network and the parameters for a phenomenological kinetics model that captures the influence of time and temperature on the yields of gas, solid, biocrude, and aqueous-phase products from isothermal hydrothermal liquefaction (HTL) of soy protein concentrate. The reaction network comprised a sole primary path, which converted soy protein concentrate to aqueous-phase products. Secondary reactions of these water-soluble compounds produced biocrude and gases. There was no direct path to biocrude formation from the biomass feedstock.

No abstract

No abstract

No abstract

There is still an urgent need to develop reliable analytical methods of O2 •– in vivo for deeply elucidating the roles of O2 •– playing in the brain. Herein, a nonenzymatic electrochemical sensor with ratiometric signal output was developed for an in vivo analysis of O2 •– in the rat brain. Diphenylphosphonate-2-naphthol ester (ND) was designed and synthesized as a specific recognition molecule for the selective determination of O2 •–. An anodic peak ascribed to the oxidation of 2-naphthol was generated via the nucleophilic substitution between ND and O2 •– and was increased with the increasing concentration of O2 •–. Meanwhile, the inner reference of methylene blue (MB) was co-assembled at the electrode surface to enhance the determination accuracy of O2 •–. The anodic peak current ratio between 2-naphthol and MB exhibited a good linear relationship with the concentration of O2 •– from 2 to 200 μM. Because of the stable molecule character of ND and its specific reaction with O2 •–, the developed electrochemical sensor demonstrated excellent selectivity toward various potential interferences in the brain and good stability even after storage for 7 days. Accordingly, the present electrochemical sensor with high selectivity, high stability, and high accuracy was successfully exploited in monitoring the levels of O2 •– in the rat brain and that of the diabetic model followed by cerebral ischemia.