Maintaining fuel stability is one important criterion in sustaining the quality of fuels. This research investigated
the production of biodiesel from waste groundnut oil and the oxidation stability of the biodiesel samples stored
under three conditions (a vacuum, a fridge and an exposure to atmosphere) by considering their saponification
values, percentage of free fatty acid, peroxide values, iodine values and viscosity. Maximum biodiesel yield was
obtained at 9 methanol/oil mole ratio, 1.0w/w%Oil KOH catalyst concentration, reaction time of 60 minutes and
reaction temperature of 60 0C. The results showed that biodiesel oxidation stability is adversely affected by
increase in saponification value, percentage of free fatty acid, peroxide value; and decrease in iodine value and
viscosity. Also, the results of these physico-chemical properties shows that vacuum is the most favourable storage
condition, compared to freezing and atmospheric condition
