Esterification of acidic oils: a way towards new products for the biorefinery
Federica Zaccheria, Simona Brini, Rinaldo Psaro, Carine Chan-Thaw and Nicoletta Ravasio
COST Action CM0903 (UBIOCHEM)
1st Workshop, Córdoba (Spain), 13-15th May, 2010
CNR ISTM, via G. Venezian 21, I-20133 Milano
e-mail:[email protected]
Ve.Li.Ca Project
Introduction
•Because of the new European directive, only biofuels produced from non-food and
secondary raw materials are permitted.
• In homogeneous alkaline conditions, transesterifcation of unrefined or crude oils
containing more than 5 wt.% of free fatty acids (FFA) is not allowed because of soap
formation (use of basic catalysts). Need of acid catalyzed pretreatments: Esterification with
sulfuric acid and sulfonic resins to make methylesters. Corrosive and costly!
• Lewis-acid catalysts have been shown to carry out both the transesterifcation of TG
and the esterification of FFAs [1, 2], although their activity could be inhibited by H2O
formed during the esterification process. Silica alumina (SiAl) and silica zirconia (SiZr)
are active in acid-catalyzed reactions.
• SiZr, a Lewis-acid catalyst, is shown here to promote esterification of FFAs and
concomitantly transesterifcation of TGs into methylesters.
•Followed by transesterification of the triglycerides (TG) in homogeneous basic conditions.
However, separation from the undesired products is difficult and costly
[1] R. Psaro, M.N. Ravasio, F. Zaccheria, European Patent Application EP 07425579.5 (2007); PCT/EP2008/062255;
WO2009037226 A1
[2] F. Zaccheria, S. Brini, R. PSaro, N. Scotti, N. Ravasio ChemSusChem, 2 (2009) 535 – 5372
Deacidification and Esterification over Silica - Zirconia
Our project in biorefinery
Ve.Li.Ca. Project on Hemp and Flax Biorefinery
Oil
Proteic hydrolisate
Starting acidity Final acidity
Conv %
ω-3
Oil
IBC
IBC
ISTM
Biolubricants
Pressing
Polyols
Jatropha Curcas (degummed)
0.84
0.18
78
1% oleic acid in rapeseed
0.98
0.16
84
3% oleic acid in rapeseed
3.33
0.27
92
Tobaccoseed
3.33
0.50
90
5% oleic acid in rapeseed
5.64
0.32
94
13% oleic acid in rapeseed
12.85
0.39
97
20% oleic acid in rapeseed
19.60
0.59
97
Olive Acidic Oils
53.67
7.44
86
Palm Fatty Acid Distillates
94.60
9.90
90
Tall Oil
98.10
8.53
91
Chicken fat
18.60
2.50
87
Animal fat 1 (cow, pig, chicken,
9.30
1.26
86
7.10
1.44
80
Glycerol
Genotype
selection
Biopolymers
ISMAC
IBBA
Packaging
Scutching
Fibre
Biomass
Oligomers and carbohydrates
Why Esters?
Triesters as
lubricants
ESTERS
www.velica.org
Experimental
Material: SiO2-ZrO2 has a SSA of 304 m2g-1
and a PV of 1.62 mL g-1. Calcination at 270
°C for 30 min in air and under vacuo for 30
min
Esters with
sterols as food
additives
Esters with
sorbitol as
surfactants
Methylesters as products
(soap, paint and varnish,
resins, solvents…)
Methylesters for fuels
ICRM
ISMAC
Transesterification and deacidification:
SiO2-ZrO2/oil= 1/10 wt.; MeOH/oil = 10/1
mol.; 180 °C, 1h, stainless steel autoclave
Analysis: Agilent 7890N GC with a flame
ionisation detector. Fatty mixtures were
derivatized
using
N,O-bis
(trimethylsylil)trifluoroacetamide
(BSTFA)
together with a standard mixture comprising
C19:0
methylester,
mono-,
diand
triglycerides
sheep)
Animal fat 2 (cow and pig)
 Successful deacidification of different natural oil: from 20 to less than 1 wt% of FFA
 Able to esterify secondary raw materials
 Good results can be explained by the best trade-off among the Lewis acidity and
surface –OH concentration features
Transesterification and Esterification of olive acidic oils
 SiO2- ZrO2 active in both esterification and transesterifcation of low
grade and waste oils
No need to remove the in situ formed water [3]
•Fulfill EN14214 regulation for biodiesel with 97.2% of FAME (for ester and
monoglycerides)
Transesterification + Esterification of Acidic Oils
100
80
% mol
Esterification of acidic oils over a commercial silica zirconia catalyst eliminates
the use of mineral acids in the pre-treatement. Moreover, after the treatment
about 50% of the oil is already converted in methylesters, thus allowing one to
reduce the amount of catalyst in the homogeneous, basic catalyzed,
transesterification step, with the great advantage of minimizing the purification
processes.
60
40
TG
FFA
20
0
DG
MG
FAME
Starting material
1
First run – 1 h
2
Second run – 1 h
3
[3] K. Suwannakarm, E. Lotero, K. Ngaosuwan, J.G. Goodwin, Ind. Eng.Chem. Res. 48 (2009) 2810
Conclusions
SiO2- ZrO2 active in both esterification and transesterification of low grade and waste oils
 SiO2- ZrO2 is a promising catalyst for the production of biofuels from low and very low grade
oils
Acknowledgements
European Commission (ERIC) , Regione Lombardia and ENI are acknowledged for the funding
of this work.