4:32 (Triple only) know that ethanol can be manufactured by: 1) reacting ethene with steam in the presence of a phosphoric acid catalyst at a temperature of about 300⁰C and a pressure of about 60–70atm; and 2) the fermentation of glucose, in the absence of air, at an optimum temperature of about 30⁰C and using the enzymes in yeast

In the hydration of ethene, ethanol is made by passing ethene and steam over a catalyst.

Water is added to ethene, this is known as hydration.

Conditions

Catalyst: Phosphoric acid (H₃PO₄)

Temperature: 300°C

Pressure: 60 atm

Fermentation is the conversion of sugar, e.g. glucose into ethanol by enzymes from yeast.

Conditions

Catalyst: Zymase (enzyme found in yeast)

Temperature: 30°C  –  The process is carried out at low temperatures as not to denature the enzymes.

Other: Anaerobic (no oxygen present) – if oxygen were present, the yeast produce carbon dioxide and water instead of ethanol.