Out of the several methodologies available for biodiesel production from triglycerides, the alkali-catalysed transesterification
is well known and globally accepted technique. Though, in case
where feedstocks used (oils or fats) has higher % of free fatty acids
or water content, the alkali reactant results in saponification which
ultimately decreases the biodiesel yield. Thus acid–base catalysed
transesterification is adopted for feedstocks having high FFA content. On reviewing the work done in different aspects of biodiesel
production, the following observations are identified for further
study.
1. Molar ratio of alcohol to oil varies between 6 and 12:1 with 10:1
for best results.
2. Range of temperature for optimum yield is 50–60°C for homogenous catalytic transesterification.
3. The best amount of catalyst used is about 1.0 wt% for base catalyst (NaOH or KOH) which are the most commonly used among
homogenous catalysts.
4. Advantage of using KOH is that, on completion of reaction,
mixture can be balanced with H3PO4 arising in formation of
products like potassium phosphate which can be utilised as
fertiliser
5. Mainly methanol has been used for production of biodiesel. To
make biodiesel fully renewable there is significant scope on