Chemistry · Ch 14 — Biomolecules
Preparation of glucose from sucrose
Preparation of glucose from sucrose
Sucrose is hydrolysed by warming it with dilute hydrochloric acid or dilute sulfuric acid for about two hours; this splits its single glycosidic linkage and converts the sucrose completely into an equimolar mixture of glucose and fructose (C12H22O11 + H2O, with H+ catalyst and heat, gives C6H12O6 glucose + C6H12O6 fructose). Glucose is then separated from the fructose in this mixture by adding ethanol while the solution is cooling: glucose is far less soluble in alcohol than fructose is, so glucose crystallises out first and can be collected by filtration, leaving fructose behind in solution. This is a simple, classic example of using …
Worked out. Reaction scheme: C12H22O11 (sucrose) + H2O, in the presence of a catalytic amount of H+ ion and heat (delta), gives C6H12O6 (glucose) + C6H12O6 (fructose). This is the acid-catalysed hydrolysis used to manufacture glucose from sucrose; the same 1:1 mixture of glucose and fructose is also called invert sugar when produced this way (see section 14.2. …