ISSN 1070-4272, Russian Journal of Applied Chemistry, 2015, Vol. 88, No. 4, pp. 676−681. © Pleiades Publishing, Ltd., 2015.
The text was submitted by the authors in English.
Biodiesel is an environmentally sustainable fuel
composed of alkyl esters of long-chain fatty acids. It
can be made from vegetable oils, animal fat, and waste
oils from the food industry [1–5]. Currently, the most
common process used for biodiesel production is through
esterification of free fatty acids (FFAs) or catalytic
transesteriﬁ cation of triglyceride with alcohols in the
presence of a suitable catalyst [6–8].
Different heterogeneous base catalysts have been
investigated for the production of biodiesel . Some
of these solid catalysts include alkali-metal and alkaline
earth metal carbonates and oxides , lithium base ceram-
ics , transition metal oxides , basic ion-exchange
resins , layered double hydroxides  and zeolites .
In 1998, Zhao et al. synthesized a new type of meso-
porous material SBA-15 with uniform two-dimensional
hexagonal structure . Compared with microporous
zeolites, this material possesses signiﬁ cantly larger pores,
thicker pore walls, and higher hydrothermal stability. For
these reasons, the discovery of SBA-15 provides a po-
tential for the material as versatile catalysts and catalyst
support for conversion of large molecules . Since pure
siliceous SBA-15 materials lack acidity, active centers
must be introduced into their framework (mesoporous
wall). Generally, incorporation of heteroatoms, such as Al
into microporous zeolites will introduce a charge imbal-
ance in the framework which is balanced by protons, thus
generating bridging hydroxyl groups (SiOHAl, Bronsted
acid sites) on these materials .
In continuation of our work on the catalytic properties
of heteropoly acids (HPAs) [14,15], we focus our attention
on the inﬂ uence of PW
/Al–SBA-15 as a catalyst in
the esteriﬁ cation reaction of palmitic acid, where the
parameters of temperature, time and reagent: catalyst
molar ratios were examined.
Synthesis of unmodiﬁ ed Al–SBA-15. Al–SBA-15
materials were prepared according to the direct synthesis
procedure reported by Yue et al.  using aluminium
Production of Biodiesel through Esteriﬁ cation of Palmitic Acid
Using 12-Tungestoposphoric Acid Supported on Nanocavity
of Aluminium Incorporated Mesoporous SBA-15
Department of Chemistry, Shahreza Branch, Islamic Azad University, 86145-311, Iran
Received May 5, 2015
Abstract—The main aim of this research is to develop efﬁ cient and environmentally benign heterogeneous
catalysts for biodiesel production. For this purpose, H
) supported on Al–functionalized SBA-15
mesoporous molecular sieve featuring a well-deﬁ ned three-dimensional (3D) mesoporosity were studied, and
the prepared catalyst (PW
/Al–SBA-15) was tested for the esteriﬁ cation process of palmitic acid to produce
methyl palmitate as a kind of biodiesel. The effects of the methanol/oil ratio, catalyst amounts, reaction time,
and reaction temperature on the conversion are also reported in this paper. More importantly, by using a 35 wt %
/Al–SBA-15 with methanol/oil molar ratio of 20 : 1 at reﬂ ux of methanol, the oil conversion of 98% after
8 h of reaction, could be achieved over the solid catalyst for at least 6 cycles under mild conditions.