Kinetic variations in Acid-Catalyzed Monosaccharide Conversion

Kinetic models for the conversion of abundant carbohydrates have often remained controversial. Direct spectroscopic observations show that conversion of ketoses by Lewis acidic salts follows an exponential time course, while the corresponding conversion of aldoses follows a second order kinetic in various solvents and using various metal chloride catalysts. Brønsted acid catalyzed conversion of glucose and fructose displays two kinetic regimes due to the competition between the kinetically favoured formation of androhydrosugars and the thermodynamically favored formation of furanics. Thus, slow kinetic phases occur towards the end of glucose conversion by Lewis and Brønsted acidic catalysis, albeit for different reasons.