B. V. S. K. Rao

Anti-microbial and anti-corrosive poly (ester amide urethane) siloxane modified ZnO hybrid coatings from Thevetia peruviana seed oil

The utilization of renewable resources for the development of organic coatings is a viable means of creating alternatives to petroleum-based chemicals which are not eco-friendly. This paper reports the synthesis of polyesteramide–urethane–silica–zinc oxide hybrid coatings from Thevetia peruviana seed oil (TPSO). The periphery of ZnO nano-particles is modified with 3-aminopropyltrimethoxysilane to prepare silica grafted ZnO composite particles. The TPSO based polyesteramide was reacted with 4,4′-diisocyanatodicyclohexylmethane in presence of siloxane modified ZnO to obtain –NCO terminated polyesteramide–urethane–silica ZnO prepolymer. These hybrid pre-polymers were casted on tin foil and cured under atmospheric moisture to obtain eco-friendly, moisture cured polyesteramide–urethanes–silica–zinc oxide hybrid coating films. The synthesized polyester and polyurethane formation was confirmed by using FT-IR and NMR spectroscopic techniques. The resultant hybrid coating films were characterized by using FT-IR, TGA, DSC, SEM, corrosion resistance and microbial resistance. Results confirm that with increase of siloxane modified ZnO content in the polyurethane matrix thermal stability, glass transition temperature and corrosion resistance improved. The antibacterial activity shows that the hybrid films exhibit excellent resistance towards Escherichia coli and Staphylococcus aureus. The salt spray test on coated panel samples show good corrosion resistance properties.

Synthesis of long-chain (E)-3-alkenoic acids by the Knoevenagel condensation of aliphatic aldehydes with malonic acid

Knoevenagel condensation of aliphatic aldehydes with malonic acid in equimolar ratio in triethylamine, which served the dual purpose of the solvent as well as the base, gave alkenoic acids in 80–88% yield as determined by acid values of the products and by gas-liquid chromatography with methyl heptadecanoate as the internal standard. The alkenoic acids were converted to methyl esters, purified by column chromatography and characterized by proton nuclear magnetic resonance, infrared and mass spectral analyses. The spectral data clearly established that the acids formed were (E)-3-alkenoic acids. The purified methyl esters were also subjected to the oxymercuration-demercuration reaction, and the mass spectra of the resulting methoxy esters confirmed the exclusive formation of 3-alkenoic acids.

A facile route for synthesis of long-chain RAC-1-S-alkylglycerols

Alkyl allyl thioethers were prepared by reaction of longchain primary thiols in hexane with allyl bromide in the presence of a phase transfer catalyst (tetrabutylammonium bromide), and aqueous alkali and were hydroxylated to rac-1-S-alkylglycerols by means of a novel reagent, cetyltrimethylammonium permanganate, in dichloromethane.

Synthesis of Azidohydrin from Hura crepitans Seed Oil: A Renewable Resource for Oleochemical Industry and Sustainable Development

The replacement of petrochemicals by oleochemical feedstocks in many industrial and domestic applications has resulted in an increase in demand for biobased products and as such recognizing and increasing the benefits of using renewable materials. In line with this, the oil extracted from the seed of Hura crepitans was characterized by an iodine value of 120.10 ± 0.70u2009g Iodine/100u2009g and a saponification number of 210.10 ± 0.40u2009mgu2009KOH/g with the dominant fatty acid being C18:2 (52.8 ± 0.10%). The epoxidised fatty acid methyl esters prepared from the oil were used to synthesise the azidohydrin with a yield of 91.20%. The progress of the reaction was monitored and confirmed using FTIR and NMR. This showed the seed oil of Hura crepitans as a renewable resource that can be used to make valuable industrial and domestic products.

Chemical composition and molecular speciation of the triacylglycerol of the oils of Lonchocarpus sericeus and Lonchocarpus cyanescens

Proximate composition of the seeds and chemical analysis of the oils of Lonchocarpus sericeus and Lonchocarpus cyanescens were determined. The oil content of the seed of L. cyanescens is 29.71u2009±u20090.20% while that of L. sericeus is 28.00u2009±u20090.50%. The seeds as well as the oils of L. cyanescens and L. sericeus were found to be rich in K, Na and Fe. Linolenic (C18:3) and oleic (C18:1) acid are the dominant fatty acids while the neutral lipids the dominant lipid class in the oils. Phytol, sterols, beta-tocopherol and hydrocarbons were identified in the unsaponifiable matters of the oils using GC–MS. The HPLC results revealed the presence of glycolipids, which are monogalactosyldiacylglycerol, digalactosyldiacylglycerol, digalactosylmonoacylglycerol and monogalactosylmonoacylglycerol. Molecular speciation of the triacylglycerol revealed the presence of molecular species with equivalent carbon chain numbers C36 (L. sericeus) and C50 (L. cyanescens) to be dominantly present in the oils.

Solvent free hydroxylation of the methyl esters of Blighia unijugata seed oil in the presence of cetyltrimethylammonium permanganate

Extraction of oil from the seed of Blighia unijugata gave a yield of 50.82 ± 1.20% using hexane in a soxhlet extractor. The iodine and saponification values were 67.60 ± 0.80 g iodine/100 g and 239.20 ± 1.00 mg KOH/g respectively with C18:1 being the dominant fatty acid. Unsaturated methyl esters of Blighia unijugata which had been previously subjected to urea adduct complexation was used to synthesize methyl 9, 10-dihydroxyoctadecanoate via hydroxylation in the presence of cetyltrimethylammonium permanganate (CTAP). The reaction was monitored and confirmed using FTIR and GC-MS. This study has revealed that oxidation reaction of mono unsaturated bonds using CTAP could be achieved under solvent free condition.

Blighia unijugata and Luffa cylindrica Seed Oils: Renewable Sources of Energy for Sustainable Development in Rural Africa

Self-sufficiency in energy requirement is critical to the success of any developing economy. Apart from the search for alternatives, there is a need to achieve energy independence, directing much focus on biofuels. Biodiesel is simple to use, biodegradable, nontoxic, and essentially free of sulfur and aromatics. Oil was extracted from the seeds of Blighia unijugata and Luffa cylindrica, subjected to chemical characterization and biodiesel production. The oil yield from the seed of B. unijugata was 50.82u2009±u20091.20% while that of L. cylindrica was 39.10u2009±u20090.20%. The biodiesel produced had ester content above 98%. The flash point of the biodiesel from B. unijugata and L. cylindrica was above 120°C while the phosphorus content was also below 1xa0ppm in both cases. The oxidative stability of B. unijugata was 44.30u2009±u20090.30xa0h, while that of L. cylindrica was lower than this value due to its high unsaturation. The copper strip corrosion value of the biodiesel was also found to be 1A. This study showed that the high free fatty acid content of B. unijugata and L. cylindrica seed oil can be reduced in a one-step pretreatment of esterification reaction using H2SO4 as catalyst thus reducing the problem of soap formation encountered when using oil with high free fatty acid for the production of biodiesel.

Physico-chemical characterization and biodiesel preparation from Ailanthus excelsa seed oil

ABSTRACT Ailanthus excelsa seed oil is identified as minor seed oil from forest origin for biodiesel production. The seed oil was initially characterized for various physico-chemical properties following standard protocols. The extracted oil was further refined and transesterified to produce biodiesel. The prepared biodiesel was evaluated for fuel properties such as the iodine value, free fatty acids, phosphorous content, flash point, cloud point, pour point, viscosity at 40°C, oxidative stability at 110°C, density, and trace metals. The properties were compared with international specifications and it was found that the oxidative stability of the prepared biodiesel was better compared to most of the biodiesels reported.