A short project on making Bio fuels domestically.

1. Preparation and purification of Biodiesel
synthesised from Vanaspati
Sumit Kumar Kar(09MS029),Sourav Kumar Sahoo(09MS032),
Debtanu Chakraborty(09MS031),Anirban Mukherjee(09MS004)
November 24, 2010

2. Figure 1: Fatty acid portion varies between C12 to C18.Fat is deposited in the
adipose tissue in the form of Triacylglycerides it is a efficient way of storing
fatty acids
Figure 2: Transesterification reaction of triglyceride to FAME (fatty acid methyl
ester).
0.1 Introduction to Biodiesel
Vegetable oils and their derivatives (ethyl esters,propyl esters,methyl esters)
are commonly referred to as biodiesels and are prominent candidates as al-
ternative diesel fuels . Biodiesel can be produced from plant oils best source
is Jatropa . Biodiesel is a renewable fuel and carbon dioxide produced from
the burning of the biodiesel is recycled into the next crop through the car-
bon cycle .Besides being a renewable and domestic resource, biodiesel reduces
most emissions while engine performance and fuel economy are nearly identi-
cal compared to conventional fuels. Several problems, however,remain, which
include economics, combustion, some emissions, lube oil contamination, and
low-temperature properties.
0.2 Theory
Biodiesel can be produced from vegetable oils through transesterification pro-
cess . Vegetable oils essentially are Triglycerides which is three fatty acids with a
glycerol backbone . Triacylglcerides with methanol in the presence of the NaOH
1

3. catalyst forms three methyl esters and Glycerol is produced as a byproduct .
The reaction is known as Transesterfication . The reaction occurs in three steps
in the first step of the reaction NaoH reacts with methanol forming a strong
base Sodium Methoxide(N aOCH3 ) . In the second step Sodium Methoxide
acts as a nucleophile and attacks a carbonyl carbon of the vegetable oil forming
tetrahedral intermediate . In the third step the Methyl Esters separate from
Glycerol backbone this is known as Cracking . These Methyl Esters compose
the Biodiesel . For Methyl Ester with 2n(varies generally from 14 to 20) carbon
atoms:
Methyl Ester(2n Carbon atoms)+ 3n − 1 O2 ⇒ nCO2 +nH2 O+Energy
2
0.3 Procedure
0.3.1 Preparation of Sodium Methoxide
1→ 50 ml 99 percent pure MeOH is taken in a 300 ml Beaker and placed in a
fume hood.
2→ 0.503 gms of Na Metal is taken in a solvent. And it is also placed in the
fume hood.
3→ From their small amount of Na metal is taken with a spatula and added to
the 300 ml Beaker containing MeoH . We wait for a few seconds to allow the
Hydrogen gas to liberate.Again a little Na Metal is added to the MeOH and
wait for a few seconds.In these way the whole 0.503 gm Na Metal is added to
the 300 ml Beaker.
0.3.2 Addition of Vegetable Oil to NaOMe
1→ Vanaspati ghee is heated at around 80o C initially till it liquifies com-
pletely.Then it is allowed to cool down to 40o C .Then 250 ml is measured
using a measuring cylinder and transferred to the reaction beaker containing
NaOMe.Now the beaker is covered with a butter paper.
2→ Now the reaction mixture is stirred for 30 to 40 mins then we wait for
another 20 to 30 minutes till dense layer glycerol collects in the bottom and
Methyl esters is collected on the top.
0.3.3 Purification
1.The entire mixture is transferred to a 500 ml separating funnel and allowed
to stand for 10 mins.The Glycerol layer formed in the bottom of the separating
funnel was collected in a beaker.
2.Then 100 ml water is added to the separating funnel and cork is fitted and
separating is shaken properly and allowed to stand for 15 minutes.
3.After 15 minutes the aqueous layer formed at the bottom of the separating
funnel was separated out leaving the top layer intact.
4.The above step was followed one more time but this time along with water 50
ml dimethyl ether was added and slowly shaked with the cork open.
5.The separating funnel was allowed to stand for 15 minutes to allow the for-
mation of the aqueous and the organic layer.
2

4. 6.The Aqueous layer was again separated out.Then the organic layer was col-
lected in a beaker.
7.To remove any moisture present in the organic layer around 10 gms of N a2 SO4
was added to the beaker.After few minutes when the solution cleared the liquid
part was separated out,kept to open overnight tom remove the volatile dimethyl
ether.
3