Peng-Lim Boey

Biodiesel production via transesterification of palm olein using waste mud crab (Scylla serrata) shell as a heterogeneous catalyst.

A recent rise in crab aquaculture activities has intensified the generation of waste shells. In the present study, the waste shells were utilized as a source of calcium oxide to transesterify palm olein into methyl esters (biodiesel). Characterization results revealed that the main component of the shell is calcium carbonate which transformed into calcium oxide when activated above 700 degrees C for 2 h. Parametric studies have been investigated and optimal conditions were found to be methanol/oil mass ratio, 0.5:1; catalyst amount, 5 wt.%; reaction temperature, 65 degrees C; and a stirring rate of 500 rpm. The waste catalyst performs equally well as laboratory CaO, thus creating another low-cost catalyst source for producing biodiesel. Reusability results confirmed that the prepared catalyst is able to be reemployed up to 11 times. Statistical analysis has been performed using a Central Composite Design to evaluate the contribution and performance of the parameters on biodiesel purity.

Dietary lipid and palm oil source affects growth, fatty acid composition and muscle α-tocopherol concentration of African catfish, Clarias gariepinus

The effects of various dietary lipids on the growth performance and muscle fatty acid and α-tocopherol concentrations of African catfish were examined. Seven isonitrogenous and isoenergetic semipurified diets were formulated with 10% lipid coming from either cod-liver oil (CLO), sunflower oil (SFO), refined, bleached, deodorized palm olein (RBDPO), crude palm oil (CPO), crude palm kernel oil (CPKO), or combinations of 5% CLO with either 5% of palm fatty acid distillates (PFAD) or 5% of residual oil in spent bleaching clay (SBC), respectively. Catfish fed with the CLO diet showed significantly (P<0.05) lower growth and feed utilization efficiency compared to fish fed with the other six diets after 7 weeks. The growth response among catfish fed with the other diets was not significantly different. Blending CLO with either PFAD or SBC alleviated the growth reduction observed in fish fed with diets having CLO as the sole lipid source. Dietary lipid source did not affect the whole-body composition or muscle lipid level among catfish fed with the various diets. The fatty acid and α-tocopherol concentration of muscle lipids in African catfish generally reflected the fatty acid profile and α-tocopherol concentration of the dietary oil that was fed. It was concluded that products from the palm oil industry could be successfully used in the diets for African catfish, and possibly other tropical catfish species, without negatively affecting growth and feed utilization efficiency. The availability, lower cost, low polyunsaturated fatty acids (PUFA) content and high vitamin E concentration of palm oil make it the vegetable oil of choice for the formulation of fish feeds in tropical countries.

Synthesis, crystal structure and spectroscopic study of Para substituted 2-hydroxy-3-methoxybenzalideneanilines

Abstract Eight Schiff bases derived from 2-hydroxy-3-methoxybenzaldehyde and different para substituted anilines have been synthesized and their structures were elucidated by physical measurements and FT-IR. NMR assignments were made using 1H, 13C NMR and aided by 2D COSY homonuclear, HMQC and HMBC heteronuclear correlation techniques. IR spectral analysis of the model compounds was found useful in understanding the degree of stabilization upon this series of enol-imino tautomers, which possess different substituents in the aniline fragment. In order to rationalize the stabilization of tautomer in solid state, the crystallography data of 1-{(4-methylphenylimino)methyl}- and 1-{(4-chlorophenylimino)methyl}-2-hydroxy-3-methoxyphenol were adopted wherein the 4-chloro (4-Cl) and 4-methyl (4-CH3) containing compounds crystallized into orthorhombic lattice with a non-centrosymmetric space group P212121. The relationship between the stabilization of bonding involved in heteronuclear six-membered ring of the tautomer and the conformation of the molecules in crystal phase was reported.

Dietary palm oil level affects growth performance, protein retention and tissue vitamin E concentration of African catfish, Clarias gariepinus.

Abstract A 9-week feeding trial was carried out to determine the effect of increasing dietary palm oil levels on growth, protein utilization efficiency and body composition of African catfish. Seven isonitrogenous and isoenergetic practical diets were formulated to contain 4%, 8%, 12% or 16% refined, bleached, deodorized palm olein (RBDPO) or 8%, 12% or 16% crude palm oil (CPO), in addition to a control diet which was not supplemented with palm oil. Growth performance of African catfish responded significantly (P

SYNTHESIS AND MESOMORPHIC PROPERTIES OF SCHIFF BASE ESTERS ORTHO-HYDROXY-PARA-ALKYLOXYBENZYLIDENE-PARA-SUBSTITUTED ANILINES

A series of new compounds o-n-hydroxy-p-n-hexadecanoyloxybenzylideneaniline and its substituted derivatives was synthesized from the esterification of palmitic acid with intermediary Schiff bases, which posssess various terminal substituents X (X = H, F, Cl, Br, OCH3, CH3, and C2H5). All compounds possess mesomorphic properties wherein compounds with X = H, F, Cl, Br, and OCH3 exhibit smectic A (SmA) phases and those with terminal substituents CH3 and C2H5 are monotropic liquid crystals showing smectic C phases (SmC). Correlation studies of the clearing temperature (Tc) of the title compounds and polarizability related to mesophase stability and molecular anisotropy are reported.

Synthesis, physical and mesomorphic properties of Schiff's base esters containing ortho‐, meta‐ and para‐substituents in benzylidene‐4′‐alkanoyloxyanilines

Three series of Schiffs base esters, 2‐hydroxy‐4‐methoxybenzylidene‐4′‐alkanoyloxyaniline, 2‐hydroxy‐3‐methoxybenzylidene‐4′‐alkanoyloxyaniline and 3‐methoxy‐4‐alkanoyloxybenzylidene‐4′‐alkanoyloxyaniline, which possess mono‐ and di‐substituted moieties at both ends of the molecules have been synthesized and their mesomorphic properties investigated along with physical characterization (elemental analysis, mass spectrometry, Fourier transform IR and high resolution NMR). The effect of lateral methoxy and polar hydroxy groups on the mesomorphism of the title compounds was studied, based on the thermal properties and textural analysis. The results indicate that compounds with the larger number of carbons in the alkyl chain prefer smectic phase formation and possess higher transition temperatures and molecular polarizability along the long axis. Further analysis shows that the greater shielding effect (through the formation of intramolecular interaction) leads to lower molecular broadening and results in higher clearing points. Increase in melting point due to the lengthening of the alkyl chain is associated with the increase in van der Waals attraction between the molecules. These compounds exhibit nematic, smectic (SmA and SmC) phases depending on the type and position of the substituents.

Synthesis and Characterization of Some New Mesogenic Schief Base Esters N-[4-(4-n-Hexadecanoyloxybenzoyloxy)-Benzylidene]-4-Substituted Anilines

Series of elongated Schiff base esters containing three aromatic rings with palmitoyl moiety as one of the terminal carbon chain and various substituents R(R=H, F, Cl, Br, OCH3, CH3, and C2H5) at the other end of molecule have been isolated, and their structures were proposed via physical measurement. The mesomorphic properties of these compounds were investigated via differential scanning calometry and polarizing optical microscopy. The thermal data indicate that all of these compounds exhibit mesomorphic properties. Although compounds with R=H, OCH3, CH3, and C2H5 show nematic phases, the remaining compounds containing halogen F, Cl, and Br are smectogenic in nature. The structural changes that result in the variation of transition temperature and the electronic polarizability of the respective molecules are discussed.

Nematic and Smectic a Phases in Ortho-Hydroxy-Para-Hexadecanoyloxbenzylidene-Para-Substituted Anilines

Four Schiff base esters containing the different substituents of R=CN, OH, SH, and NO2 were synthesized, and the physical characterization was carried out along with spectroscopic techniques (FT-IR and NMR). Thermal properties were analyzed by using differential scanning calometry (DSC), and their liquid crystal textures were observed under polarized optical microscope. All compounds thus obtained exhibit mesomorphic properties of which the alignment of molecules are inclined to either nematic, N (R=SH), or smectic, SmA (for R=CN, OH, and NO2). The unidentifiable subphases in crystal region were recorded in all compounds except that with R=OH. The presence of a lateral hydroxyl group has been claimed to contribute to the enhanced molecular ordering, leading to a higher clearing temperature.

Synthesis and mesomorphic properties of 7‐acyloxy‐3‐(4‐acyloxyphenyl)‐4H‐1‐benzopyran‐4‐one

A new homologous series of 7‐acyloxy‐3‐(4‐acyloxyphenyl)‐4H‐1‐benzopyran‐4‐ones was synthesized and characterized by elemental analysis and spectroscopic techniques along with thermal behaviour study using differential scanning calorimetry. Texture observation was performed under the polarizing optical microscope from which the derivatives were found to exhibit different molecular organizations as exemplified by various mesophases. Whilst the compounds containing butanoyloxy and hexanoyloxy groups behave as nematogens, the other compounds with heptanoyloxy and longer side chains show a SmC phase. The octadecanoyloxy derivative was the only member showing a monotropic SmC phase. The difference in phase behaviour is discussed based on the molecular structure and the presence of a lateral dipole which can be associated with the intermolecular interaction within the mesophase.

Synthesis and Mesomorphic Properties of 2-(4-Alkyloxyphenyl)benzothiazoles

A homologous series of 2-(4-alkyloxyphenyl)benzothiazoles with an even number of carbons in the terminal alkoxyl chain was synthesized and characterized. The structure of the compounds was postulated using elemental analyses, FT-IR, NMR, and mass spectrometry techniques. Their liquid crystalline properties have been investigated by optical polarizing microscopy, DSC, and X-ray diffraction (XRD) techniques. Whilst the n-octyloxy to n-hexadecyloxy derivatives exhibited a monotropic smectic A phase, the n-ethoxy to n-hexyloxy and the n-octadecyloxy derivatives were not mesogenic. The mesomorphic properties of the present series were compared with other structurally related series to establish the chemical structure-mesomorphic properties relationship.