Utilization of agricultural
waste such as nonedible seed oil for
the synthesis of biodiesel via catalytic transesterification is one
of the effective ways for the partial replacement of petroleum-based
fuels in the area of renewable energy development and is beneficial
to CO, CO
2
, and unburned hydrocarbon (HC) emission reduction
to the environment. In this regard, the current study investigates
the synthesis of fatty acid methyl esters (FAMEs) from
Croton macrostachyus
kernel oil by considering parameter
interaction and optimization to maximize the yield of fatty acid methyl
esters (FAMEs). The response surface methodology–central composite
design (RSM-CCD) was applied to optimize the
C. macrostachyus
fatty acid methyl ester (CMKO-FAME) synthesis process by varying
the process parameters such as reaction time (1–2 h), molar
ratio (6:1–12:1), and catalyst loading (1–2 wt %). The
optimum conditions for the transesterification of
C.
macrostachyus
kernel oil (CMKO) were found to be a
methanol to oil ratio of 11.98:1, catalyst loading of 1.03 wt %, and
reaction time of 2 h, resulting in the conversion of 95.03 wt %
C. macrostachyus
kernel oil into its mono FAMEs.
The fuel properties of CMKO and its FAMEs were determined based on
ASTM D6751 and EN 14214 standards. Further, the CMKO and its FAMEs
were characterized using Fourier transform infrared (FT-IR), gas chromatography–mass
spectrometry (GC–MS), and nuclear magnetic resonance spectroscopy
(NMR). The fatty acid composition of CMKO was myristic acid (1.36%),
palmitic acid (11.35%), stearic acid (5.11%), oleic acid (18.64%),
gadoleic acid (0.34%), linoleic acid (49.084%), and linolenic acid
(14.1%). The purity of the produced methyl esters was determined by
1
H NMR and found to be 95.52%, which was quite in good agreement
with the experimentally observed yield of 95.39 wt %. The produced
CMKO-FAME was blended with diesel fuel at various ratios (B5, B10,
B15, and B20) to evaluate the engine performance and emission characteristics
in a diesel engine. The engine brake thermal efficiency is lower,
the brake-specific fuel consumption (BSFC) using CMKO-FAME blends
is higher, and the temperature of exhaust gas emitted after combustion
also increased as compared to diesel fuel. Similarly, using produced
FAME blends, the emission emitted such as HC, NOx, and CO is reduced.
However, the engine fueled with the produced FAME blends increased
the level of CO
2
into the atmosphere when compared to diesel
fuel. The performance and emission characteristics of diesel engine
result show that the blend of CMKO-FAME and diesel can be used as
a fuel in a diesel engine without any modification of the engine.