Kinetic pH Titration to Predict the Acid and Hydrothermal Conditions for the Hydrolysis of Disaccharides: Use of a Microcapillary System

Abstract

The hydrolysis of disaccharides was conducted using a microcapillary system under hydrothermal conditions (up to 190°C at 10 MPa and pH 4–11). The hydrolysis reaction showed a sigmoidal progression with time, especially under alkaline conditions. Analysis using a kinetic model yielded the reaction induction period. The specific pH value (pHamb) at the induction time, which is the pH value corresponding to the progression of disaccharide hydrolysis, was peculiar to each disaccharide. Finally, the calculation of the electron density around the oxygen atom of the glycosidic bond between saccharides was found to roughly predict the pHamb value required for the progression of hydrolysis.

Single‐Step Sustainable Production of Hydroxy‐Functionalized 2‐Imidazolines from Carbohydrates

“…The good tolerability of the glycosidic bonds to hydrolysis into monosaccharides in the weak basic medium possibly accounts for these more modest results. [29] Indeed, when a two-step reaction strategy, comprising fructose production from inulin hydrolysis catalyzed by InCl 3 in aqueous medium and subsequent aminolysis of generated fructose to the desired HI product in the presence of EDA, was employed for one-pot conversion of inulin, HI yield can be achieved up to 53 % (Table 2, entry 8). Besides the scope extension of carbohydrate feedstocks, varied 1,2-diamines can be also utilized to synthesize the corresponding hydroxy-functionalized heterocyclic product.…”

Kinetics for the Subcritical Treatment of Glucose Solution at Various Concentrations

“…Further, because of this property, subcritical water exhibits catalytic activity for many reactions. Many kinds of reactions occur in subcritical water, such as hydrolysis of polysaccharides and peptides, and reverse hydrolysis (Sasaki et al, 1998;Oomori et al, 2004;Sato et al, 2004;Faisal et al, 2005;Haghighat Khajavi et al, 2005;Haghighat Khajavi et al, 2006;Wang et al, 2010;Kobayashi et al, 2012;Gao et al, 2014;Shimanouchi et al, 2019). In addition, saccharides can isomerize to form other types of saccharides; for example, glucose isomerizes to fructose and mannose in subcritical fluids (Usuki et al, 2007;Daorattanachai et al, 2012;Lü et al, 2012;Gao et al, 2015a).…”