Biodiesel is a mixture of esters derived from fatty acids.
Fatty acids can also be called aliphatic monocarboxylic acids , that is organic compounds containing the carboxyl group, or rather a hydroxyl group (O-H) linked to a carbonyl group (C=0).
Fatty acids are the main ingredients of all the complex lipids of vegetable and animal fats.
 Structure saturated and unsaturated fatty acids
 Butyric acid (Fatty acids)

Use
Biodiesel is used as fuel in vehicles as substitute of diesel oil.
What is diesel oil?
It is a compound obtained by crude oil distillation.

 Diesel is a derivate of petroleum and it is a fossil fuel.
Crude oil ( Fossil fuel)
• Biodiesel, instead, is a vegetable fuel
Biodiesel ( Vegetable fuel)

Fossil fuel
Fossil fuels emit a lot of carbon dioxide that remains in the atmosfere and gives way to the negative consequences of the enhanced greenhouse effect .

Vegetable fuel
Vegetable fuel emits small quantities of carbon dioxide.
This fact makes biodiesel a low environmental impact fuel, because carbon dioxide produced by it, is absorbed by plants in
1 year .

There are, today, three different generations for the biodiesel production.
 Reaction
 Biodiesel preparation in progress with a phase of glycerin at the bottom.

Biodiesel density, viscosity and heat value
These are the three common and simply methods to determine the quality of biodiesel density
Heat value viscosity

micropipets
Determination of density
Material:
200 μl micropipette, 100 μl micropipette, 50 μl micropipette, analytical balance, 3 beakers.
Procedure: take the sample with micropipette, weigh it whit an analytical balance and record the weight.
Repeat the operation with all micropipettes for all sample.
Run the numbers.

Determination of viscosity
Meterial:
3 Pasteaur pipettes, teats, ruler, marker, chronometer.
Procedure: draw with help of a ruler a path of 4 cm on all pipettes; take the biodiesel slightly above the upper notch; remove the teats and plug with a finger; remove the finger and let down the biodiesel till the under notch, measuring the time path with a chronometer and record it; repeat the operations 3 times for all the sample.

Our data
Sample 1 Sample 2 Sample 3
0,1022 g / ml 0,1010 g / ml 0,1004 g / ml Density
50 microlitres sample
Density
100 microlitres sample
0,9760 g / ml 0,9422 g / ml 0,9902 g / ml
Density
200 microlitres sample
0,9965 g / ml 0,9750 g / ml 0,1472 g / ml
Viscosity (seconds) 10'' 20''
Sample number 1: biodiesel obtained from methanol + sodium hydroxide;
Sample number 2: biodiesel obtained from ethanol + potassium hydroxide;
Sample number 3: biodiesel obtained from methanol + potassium hydroxide.
20''

Determination of heat value
Material:
20 ml beaker, wick, paper clip, 100 ml graduated cylinder, glass stick, tin, thermometer, support for separating funnel.
Procedure: calibrate the beaker and weigh 30.0 grams of biodiesel (it must be constant in all tests); insert in the beaker the wick with the paper clip; cut the top of the tin, make two holes, opposite each other, at the top; insert the glass stick in the holes; measure 100 ml of water with the cylinder, tare the tin and pour the water;
Position the tin on the support for separating funnel; measure the water temperature; fire up to wick and controls the time that water takes to heat up to 20
°
C;
Weigh the water and record weight, temperature and time.
Repeat the operations for 3 times and for all the samples.
Analyze the data and compare it with the official data of diesel.

Our data
Biodiesel's weight
(grams)
Water's weight (start)
Water's weight (final)
Start temperature
Final temperature
Time
(minutes)
Sample 1
50,0 g
100,0 g
96,5 g
20
°
40
°
1.00'
Sample 2
50,0 g
Sample 3
50,0 g
100,0 g
94,0 g
20
°
40
°
2.00'
100,0 g
98,0g
20
°
40
°
4.00'

density
Viscosity (cP) specific gravity: 0.89
temperature: 68
°
F
Heat value
Diesel Data
Diesel
0,832 g / ml
76,2
43400-44800 KJ / Kg
According to these data we can say that our biodiesel sample n
°
1 is the most similar to diesel.