Silva and Cardoso, J Thermodyn Catal 2016, 7:2
DOI: 10.4172/2157-7544.1000173
Research Article Open Access
Journal of
Thermodynamics & Catalysis
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ISSN: 2157-7544
Volume 7 • Issue 2 • 1000173
J Thermodyn Catal
ISSN: 2160-7544 JTC, an open access journal
Assessing the Activity of Solid-Suported SnCl
2
Catalysts on the Oleic Acid
Esterification for Biodiesel Production
Márcio José Da Silva* and Abiney Lemos Cardoso
Chemistry Department, Federal University of Viçosa, Viçosa, Minas Gerais State, Brazil
*Corresponding author: Márcio José Da Silva, Chemistry Department,
Federal University of Viçosa, Viçosa, Minas Gerais State, Brazil, E-mail:
silvamj2003@ufv.br
Received June 01, 2016; Accepted July 06, 2016; Published July 13, 2016
Citation: Silva MJD, Cardoso AL (2016) Assessing the Activity of Solid-Suported
SnCl
2
Catalysts on the Oleic Acid Esterifcation for Biodiesel Production. J
Thermodyn Catal 7: 173. doi:10.4173/2160-7544.1000173
Copyright: © 2016 Silva MJD, et al. This is an open-access article distributed under
the terms of the Creative Commons Attribution License, which permits unrestricted
use, distribution, and reproduction in any medium, provided the original author and
source are credited.
Keywords: Esterifcation; Tin chloride; Free fatty acids;
Heterogeneous catalysis
Introduction
Te exhaustion of the fossil petrol reserves, in combination with
the environmental impact generated by the green-house efect gas
emission has stimulated the search by alternative and renewable
feedstock for energy production [1]. Besides this crescent demand, the
industry chemistry and academy in all parts of world are developing
environment friendly technologies for the production of alternative
fuels [2]. Nowadays, the biodiesel is a “green” alternative fuel that has
arisen as an attractive option, mainly because it’s less pollutant than
fossil diesel and can be obtained from renewable sources. Currently,
the biodiesel is manufactured from alkaline transesterifcation of edible
or non-edible vegetable oils via a well-established industrial process
[3,4]. However, there are serious drawbacks related to its conventional
production process, such as a greater generation of efuents and salts
from neutralization steps of the products and wastes, the use of non-
recyclable catalysts and the incompatibility with acid raw material
with high amount of FFA [4,5]. Tese important features have hardly
afected the fnal cost to biodiesel production [6].
An interesting alternative for lower biodiesel price is produce it
directly from low cost lipidic raw materials are normally rich in FFA
[7]. It should be mentioned that even though traditional mineral
acids are an inexpensive catalysts able to those processes, they are
equally corrosive, are not reusable and results in a large generation of
acid efuents which should be neutralized at the end of the reaction,
leaving greater amount of salts to be disposed of into environment
[7,8]. Terefore, to develop recyclable alternative catalysts for FFA
esterifcation reactions presents in low cost feedstokes and food industry
rejects can be an option strategically important, and undoubtedly can
produce biodiesel at more competitive cost via a cleaner technology
[9]. Recently, several works have been described the development of
heterogeneous catalysts based on acids solids that appear to ofer a
good perspective to make the biodiesel production more environment
friendly [10,11]. Nevertheless, serious technological drawbacks such
as drastic conditions reaction, the rigorous control of raw material
quality in relation to water content, beyond of the leaching catalyst
provoked by presence of alcohol seems suggest that those process
yet are hard to control.
Alternatively, to develop catalysts for the direct conversion into
biodiesel of lipid wastes basically constituted of FFA, or yet for the
pre-esterifcation of raw materials that have high acidity seem be
also a challenge to be overcome [12]. Nowadays, the majority of the
catalysts conventionally used in the FFA esterifcation reactions are
Brønsted acids. However, features such the higher corrosive character
besides greater generation of residues and salts compromises the
use of these traditional catalysts [13]. Lewis acids can be interesting
alternative catalysts for biodiesel production. However, their high cost,
the manipulation difcult and the intolerance to water of compounds
traditionally used such as BF3 and others common reagents of organic
synthesis, also does not favor the use of these latters in FFA esterifcation
at industrial scale [14].
Particularly, we have concentrating eforts in developing an
alternative esterifcation processes based on tin chloride, an simple,
easily handling, water tolerant and inexpensive Lewis acid [15,16].
On the other hand, the SnCl
2
is also most attractive, because it is are
commercially available and easy to handle [17]. Moreover, its display
remarkably low toxicity, is tolerant to water, economically cost efective,
and can be used in recyclable processes [18]. Although Sn(II) catalysts
have been used in homogeneous phase, they are though less corrosive
than mineral acids [19]. In this work, the application of solid supported
SnCl
2
catalysts on FFA esterifcation is described. Our intention was
assess if supported tin(II) catalysts can be potentially used on direct
conversion of FFA into biodiesel via ethanol esterifcation reactions.
Te reusability, the less corrosion, the mild condition reactions and
the compatibility with ethanol, which is also a renewable raw material,
comprise positive aspects of this process. Moreover, the stability and
possibility of reuse of supported Sn(II) catalysts were investigate.
Abstract
The search for cleaner methodologies has forcing the chemical industry to seek environmentally benign acid
catalysts. SnCl
2
.2H
2
O is an affordable commercially Lewis acid, water tolerant and easy to handling, cheaper, and
less corrosive. Recently, we have demonstrated that it is an effcient catalyst to produce biodiesel in homogeneous
catalysis conditions. In this work, we have supported SnCl
2
.2H
2
O over different solid matrix (i.e., such as SiO
2
,
Nb
2
O
5
and ZrO
2
) and evaluated its catalytic activity in FFA esterifcation reactions. In this case, the reaction occurs in
heterogeneous phase bringing with itself all the pertinent advantages to this rational system as the best separation
of products and reuse of the catalyst. It was appraised reaction parameters such as thermal treatment temperature
nature of the support; leaching test was also accomplished.