The CaO is preferred between the alkaline earth oxide catalyst due its low cost, high catalytic activity and high catalytic stability (Becerra et al, 2011).Though a delay in catalytic activity at the beginning of the oil palm transesterification reaction with CaO is observed (latency time), the reaction time necessary for reaching specific biodiesel yields is increased when compared with homogeneous catalysts
. In previous works, it was determined that this latency time correspond to the time required for the methoxide ion formation at the solid catalytic surface; consequently, a prior catalyst activation, i.e., the methoxide formation, can accelerate the reaction (Kawashima et al, 2009; Granados et al, 2007).
However, for the production of biodiesel, various types of oils (as raw material), homogeneous catalysts
(potassium hydroxide, sodium hydroxide, sulphuric acid and supercritical fluids), heterogeneous catalysts and enzyme (lipase) can be used (Marchetti et al., 2007).The blend of biodiesel with petro-diesel could also be used in transport sector.
are also growing in popularity owing to their unique features such as selectivity, high activity and varied application.
Integrated biodiesel production: a comparison of different homogeneous catalysts
Alternatively, to overcome these operational challenges, the use of homogeneous catalysts
has been investigated for in situ upgrading of heavy oil.
Biodiesel (methyl ester, ME) produced by transesterification process using homogeneous catalysts
requires to be purified by removing impurities and by product (glycerol) via water washing process.
As to the homogeneous catalysts
, manganese and nickel in the ionic form did not influence the degradation rate of BA.
Methods for the recovery and recycling of homogeneous catalysts
were introduced in a keynote presentation by Walter Leitner (RWTH Aachen, Germany).
Johnson Matthey is a leading manufacturer and supplier of Platinum Group Metal (PGM) heterogeneous and homogeneous catalysts
. Johnson Matthey provides high-throughput screening services for the identification of optimal catalysts as part of its complete catalyst program -- helping pharmaceutical companies get their products to market fasten Johnson Matthey's customers benefit from a technical support staff with over 100 years of experience in catalyst development, as well as a state-of-the-art screening facility that houses the most current catalyst screening equipment.
Only homogeneous catalysts
have proved so highly selective.
Bohm, "Particle forming process in slurry polymerization of ethylene with homogeneous catalysts
," Polymer Communications, vol.