Slides in this set
Ethanol can be made through two different chemical
1. Hydration of ethene
Industrially, ethene can be hydrated to produce ethanol, using
phosphoric acid as a catalyst.
The reaction is reversible though, so the conversion of ethene
is incomplete only 5% of the ethene is converted to ethanol
each time the reagents pass through the reactor.
Unreacted gases are recycled and passed through the reactor
again, giving an overall conversion of 95%.…read more
Carbohydrates can be converted into ethanol and carbon
dioxide through fermentation. Sugar or starch is usually used
as the carbohydrate source, and the enzyme zymase in yeast is
used as a catalyst.…read more
2. Fermentation continued....
At temperatures above or below 37oC the reaction is slow or
Zymase from yeast is an enzyme below 37oC it reacts slowly, above
37oC the enzyme is denatured and loses efficiency.
The ethanol produced is toxic to the yeast, limiting the concentration
of ethanol that can be produced by fermentation to a concentration
of about 14%.
Fermentation of carbohydrates to ethanol is anaerobic (does not
require oxygen) fermentation must be carried out in the absence of
air to prevent oxidation of the ethanol to ethanal or ethanoic acid,
which would affect the flavour of the product.…read more