Heterogeneous catalysis is a catalytic
process wherein the catalyst is in a distinct phase as that of the reactants. The
current article focuses on the applicability of residual ash from sugarcane
leaves after recovery of silica as a heterogeneous catalyst for the production
of biodiesel from trans-esterification of the Calophyllum inophyllum oil and methanol to yield fatty acid methyl
esters (FAME), a renewable fuel source. Various vital parameters were studied
for optimizing the biodiesel yield. The transesterification process was found
to be significantly influenced by the methanol to oil proportion, catalyst
load, and the temperature of the process and the parameters were optimized by
response surface methodology. The highest fatty acid methyl ester

Keywords: Biodiesel, Sugarcane leaf ash,
Transesterification, Calophyllum
inophyllum oil.

1. INTRODUCTION                                                                         

With an
increasing global demand to restraint the environmental pollution and to encourage
the use of renewable energy sources, biodiesels have emerged as major contenders
for petroleum alternatives as a sustainable and renewable energy.  Researches on biodiesel have seen a boom over the past several years
and have shown to be produced from a broad variety of edible sources,
non-edible oils and animal fats. It is a mono-alkyl ester of long chain fatty
acid that has been transesterified by an alcohol at the terminal
acid residue. Biodiesels are used as petro-diesel fuel additives, owing to the
lack of aromatics, negligible sulfur content, higher lubricity and very high
cetane values.

Biodiesel
have been synthesized from various kinds of edible oils such as palm oil,
sunflower oil, cotton seed oil etc. and have been tested
successfully in diesel engines. Though there has been success achieved,
synthesis of biodiesel from edible oils are not considered as feasible due to
their higher capital investment and wastage of food resources. India accounts
for greater investments because they import major amount of edible oils and
therefore biodiesel synthesis from edible oil is not acceptable. Thus the
non-edible oil sources started gaining much importance and there have been many
non-edible feedstock reported. One such non-edible oil is Calophyllum
inophyllum , that is an important source for biodiesel production.

 Calophyllum
inophyllum is an evergreen tree which belongs to Clusiaceae family
and is a source of an oil-rich, non-edible oilseed. The Calophyllum
inophyllum seed oil has many beneficial aspects with respect to biodiesel
feedstock and is an economical and widespread source for bulk biodiesel
production. The oil content in the Calophyllum inophyllum kernels make upto
70% of the weight, of which, 71% constitute mainly of unsaturated fatty acid
molecules (mainly linoleic and oleic acids). The oil has an undesirable taste
and odor. The fatty acid methyl ester molecules produced by transesterification
of Calophyllum inophyllum oil using methanol meets the standards and
requirements necessary for a biodiesel, as set by the European Union and
American standards.

Synthesis
of biodiesel using solid catalysts instead of homogeneous liquid catalyst could
provide a promising alternate for the economical production of biodiesel, an
opinion largely backed by the reusability of the catalyst, while also providing
the conditions for simultaneously carrying out both transesterification and
esterification processes. The separation of the catalyst from the reaction
mixture is easier than homogeneous catalysts; a mere filtration is all that is
required. Other benefits of using a solid or heterogeneous catalyst is the subsidized
quantities of the catalyst required for catalysis, high surface area to volume
ratio of the solids, where the triglycerides can anchorage on the pores of the
solid for improving the reaction, while also reducing the need for effective
water washing. The production of waste stream is cut
down and hence subsequent separation and purification is simplified.
Additionally, the catalysts are generally non corrosive. Heterogeneous
catalysis can be done either by base catalyzed transesterification or by acid
catalyzed transesterification. Other heterogeneous catalysts having both acidic
and basic sites are used that could esterify FFA and at the same time
transesterify the triglycerides to biodiesel.