Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry of Vernonia galamensis oil

Matrix-assisted laser desorption/ionization (MALDI) time-of-flight (TOF) mass spectrometry (MS) has been used to identify eight triacylglycerols (TAG) in Vernonia galamensis oil (VO). The TAG include trivernolin, divernoloylstearoylglycerol, divernoloyloleoylglycerol, vernoloyllinoleoylstearoylglycerol, vernoloyllinoleoyloleoylglycerol, and vernoloyldilinoleoylglycerol. Samples for the MALDI/TOF/MS analysis were prepared with alpha-cyano-4-hydroxycinnamic acid (matrix) in an acetonitrile/tetrahydrofuran solvent system. A mol ratio of matrix/VO (44:1) gave reproducible composite spectra, resulting in resolutions greater than 8,000 and signal-to-noise ratios of above 1000 for the most abundant molecular species. 1,3-Dioleoyl-2-stearoylglycerol and 1,2-dioleoyl-3-palmitoylglycerol were used as calibration standards.     

New carbon composite adsorbents for the removal of textile dyes from aqueous solutions: Kinetic,equilibrium, and thermodynamic studies

New carbon composite materials were prepared by pyrolysis of mixture of coffee wastes and red mud at 700 °C with the inorganic: organic ratios of 1.9 (CC-1.9) and 2.2 (CC-2.2). These adsorbents were used to remove reactive orange 16 (RO-16) and reactive red 120 (RR-120) textile dyes from aqueous solution. The CC-1.9 and CC-2.2 materials were characterized using Fourier transform infrared spectroscopy, Nitrogen adsorption/desorption curves, scanning electron Microscopy and X-ray diffraction. The kinetic of adsorption data was fitted by general order kinetic model. A three-parameter isotherm model, Liu isotherm model, gave the best fit of the equilibrium data (298 to 323 K). The maximum amounts of dyes removed at 323 K were 144.8 (CC-1.9) and 139.5 mg g^?1 (CC-2.2) for RO-16 dye and 95.76 (CC-1.9) and 93.80 mg g^?1 (CC-2.2) for RR-120 dye. Two simulated dyehouse effluents were used to investigate the application of the adsorbents for effluent treatment.     

Calculating the Thermal Conductivity of Heated Powder Compacts

This work is devoted to the theoretical understanding of the microstructure and thermal conductivity relationships of compacted ceramic powders in the initial, nondensifying stage of sintering. A model based on surface diffusion of vacancies for the growth of the neck between particles is combined with numerical fully three-dimensional code calculations, which solve for the effective heat conductivity coefficient of lightly sintered particles. The predictions of the model are in agreement with experimental observations. The approach presented can be applied to solve a series of related problems, like dielectric properties, with arbitrary microstructure and multicomponent composite of the powders.     

The use of lipase (acetone powder) from Vernonia galamensis in the fatty acid analysis of seed oils

Examined in this study is a potential application of Vernonia galamensis lipase (acetone powder) in enzyme-catalyzed hydrolysis of seed oils, most especially of those containing reactive functionalities which are easily affected under drastic hydrolytic and methylating/transesterification conditions during fatty acid analysis. Eight seed oils from V. galamensis, Ximenia kaffra, castor, corn, soyabean, palm kernel, sunflower and olive were hydrolyzed by lipase (acetone powder) followed by methylation using diazomethane in ethyl ether. Results obtained showed that the lipolytic hydrolysis of triglycerides by V. galamensis lipase (acetone powder) was probably nonspecific and did not result in isomerization and as such hydrolyzed the triglycerides of the seed oil in a fashion that the resulting fatty acids were unaltered during hydrolysis. The fatty acids obtained were representative of the parent seed oils. Values reported for the various seed oils were similar to those of previous studies.     

Syntheses of 12-aminododecanoic and 11-aminoundecanoic acids from vernolic acid

12-Aminododecanoic acid and 11-aminoundecanoic acid, monomer precursors for nylon-12 and nylon-11, respectively, have been synthesized from vernolic (cis-12,13-epoxy-cis-9-octadecenoic) acid via a reaction sequence that includes the formation of 12-oxododecanoic acid oxime. Saponification of vernonia oil, followed by a low-temperature recrystallization at −20°C, gave 51% vernolic acid (97% purity, m.p. 23–25°C). Hydrogenation afforded cis-12,13-epoxystearic acid (m.p. 52–54°C, lit. m.p. 52–54°C), which upon oxidation with periodic acid in tertiary butyl alcohol gave 12-oxododecanoic acid with an isolated yield of 71.0%. Reaction of the oxoacid with hydroxylamine hydrochloride gave 12-oxododecanoic acid oxime, which was catalytically reduced to give 12-aminododecanoic acid with a yield greater than 85% and a melting point of 184–186°C (lit. m.p. 185–187°C). 11-Aminoundecanoic acid was prepared from the 12-oxododecanoic acid oxime via a three-step reaction sequence that involved a Beckmann rearrangement, Hofmann degradation, and hydrolysis. Thus, the aldoxime acid was hydrolyzed in the presence of nickel acetate tetrahydrate to give 11-carbamoylundecanoic acid (48% yield, m.p. 129–131°C, lit. m.p. 129–130°C). The amide was then treated with a solution of sodium methoxide and bromine at 70–80°C to give 11-(methoxycarbonylamino)undecanoic acid at 75% yield (m.p. 84–86°C; elemental analysis, calculated for C₁₃H₂₅NO₄: C, 60.19; H, 9.73; N, 5.40; O, 24.68%; found C, 60.02; H, 9.81; N, 5.26; O, 24.91%), which upon alkaline hydrolysis and subsequent neutralization gave 11-aminoundecanoic acid at 34% yield (m.p. 189–192°C, lit. m.p. 190°C). Mass spectrometric and ¹³C nuclear magnetic resonance data of the previously unreported 11-(methoxycarbonylamino)undecanoic acid is provided.     

Synthesis and isolation of epoxy secondary amidesvia direct amidation ofVernonia galamensis seed oil

Vernonia galamensis oil, containing naturally epoxidized triglycerides, was reacted withn-butylamine,n-pentylamine andn-hexylamine to afford high yields of epoxidized secondary amides. Three reaction conditions were investigated: (i) reflux with amines as solvents, (ii) reflux with hexane as the solvent and (iii) room temperature with the amines as solvents. Reactions with amines as refluxing solvents were completed in 1–5 h, while those with hexane went to completion within 2 to 5 d. Room temperature reactions were onlyca. 80% complete after several days. Reactivity was increased with higher amine homologs at both reflux and room temperature reaction conditions. Isolated yields of epoxy-containing amides were about 80% with purity exceeding 96% in all cases. Spectroscopic characterization of the previously unreported alkyl-vernolamides is provided.     

Rapid transesterification and mass spectrometric approach to seed oil analysis

Fatty acid composition of seed oil is determined in less than one hr using a quantitative one-vial technique. The method of analysis requires alcoholic solutions of sodium methoxide mild enough for epoxy and polyunsaturated oils. Separation and characterization of component fatty acids were accomplished by high resolution gas chromatography-mass spectrometry. Using this method,Vernonia galamensis seed oil is shown to contain 79–80% vernolic (cis-12,13-epoxy-cis-9-octadecenoic) acid.Amaranthus cruentus, a West African vegetable crop, is shown to contain 17.3% palmitic acid, 3.2% stearic acid, 22.7% oleic acid, 54.7% linoleic acid and 2.1% linolenic acid.     

Biodegradation ofVernonia galamensis seed Oil byAcinetobacter andPseudomonas sp.

The biodegradability ofVernonia galamensis seed oil (VO) has been demonstrated with two environmental bacterial strains,Acinetobacter Iwoffi (HU 3955), andPseudomonas sp. (HU 4020). A time-dependent increase in the degradative activities of both bacteria species was apparent. There wasca. 60% decrease in the amount of VO over an eightday incubation period. Additionally, lipolytic activity was evident from the amount of free fatty acid (FFA) that was generated. The percent FFA of the residual oil were 82% for thePseudomonas strain, and 62% for theAcinetobacter strain. The weight per epoxy value of the VO in the fermentation medium remained relatively constant over the incubation period, suggesting the lack of preference for either the epoxidized or nonepoxidized acids present in VO.     

Synthesis of toughened elastomer from vernonia galamensis seed oil

This paper examines the synthesis of a toughened elastomer fromVernonia galamensis seed oil by reacting vernonia oil with vernonia oil-derived suberic acid (octanedioic acid), and cross-linking the pre-polymer in the immediate presence of cross-linked polystyrene preparedin situ. The paper also demonstrates that the progress of reaction can be followed by monitoring the generation of hydroxyl groups using infrared spectroscopy. Analysis of some crystalline material on the cooler parts of the reaction vessels revealed the presence of component fatty acids of vernonia oil. Transmission electron microscopy characterization of the synthesized toughened elastomer suggests that vernonia oil-suberic acid polyester and polystyrene polymer are interpenetrating.     

A comparative study of concrete properties using coconut shell and palm kernel shell as coarse aggregates

The high cost of conventional building materials is a major factor affecting housing delivery in Nigeria. This has necessitated research into alternative materials of construction. This paper presents the results of an investigation carried out on the comparative cost analysis and strength characteristics of concrete produced using crushed, granular coconut and palm kernel shells as substitutes for conventional coarse aggregate in gradation of 0%, 25%, 50%, 75% and 100%. Two mix ratios (1:1:2 and 1:2:4) were used. A total of 320 cubes of size 100×100×100 mm were cast, tested and their physical and mechanical properties determined. The results of the tests showed that the compressive strength of the concrete decreased as the percentage of the shells increased in the two mix ratios. However, concrete obtained from coconut shells exhibited a higher compressive strength than palm kernel shell concrete in the two mix proportions. The results also indicated cost reduction of 30% and 42% for concrete produced from coconut shells and palm kernel shells, respectively. Considering the strength/economy ratio, it was concluded that coconut shells were more suitable than palm kernel shells when used as substitute for conventional aggregates in concrete production.