Environmental Engineering Reference
In-Depth Information
BOX 18.1: THE TWELVE PRINCIPLES OF GREEN CHEMISTRY
1. Prevention instead of remediation
2. Atom efficiency
3. Less hazardous chemicals
4. Design safer chemical products
5. Safer solvents and auxiliaries
6. Energy efficient by design
7. Renewable raw materials
8. Shorter synthesis
9. Catalytic methodologies
10. Design for degradation
11. Analysis for pollution prevention
12. Inherently safer chemistry
O
O
C
17
H
31
O
O
C
17
H
31
O
O
O
C
17
H
31
O
C
17
H
31
O
O
OH
base
OH
+
HO
O
C
17
H
31
O
C
17
H
31
+ 3 CH
3
OH
Linoleic oil
MW = 878 g/mol
Methanol
MW = 32 g/mol
Methyl linoleate
MW = 294 g/mol
C
17
H
31
-C(O)OCH
3
Glycerol
MW = 92 g/mol
O
H
3
CO
Atom eficiency: [3 × 294/(878 + 3×32)] × 100% = 91%
FIGURE 18.2
Atom efficiency of FAME production. Linoleic acid was used as a model fatty
acid compound. It is one of the major components of soybean oil. In practice, biodiesel oils,
such as vegetable oils and waste oils, consist of a mixture of saturated (e.g., stearic acid),
mono-unsaturated, di-unsaturated, and poly-unsaturated fatty acid esters.
production technology, where often the use of large amounts of bases is the cheapest
way to convert oils into FAME. Also, the origin of methanol (the solvent needed for
esterification) needs to be judged. In other words, there is no general answer to the
question whether biodiesel production complies with the twelve principles, and every
biodiesel production facility has to be evaluated separately.
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