Mode of Coordination and Chemical Reactivity of Alpha-Imine Hydrasone Ligands

Interaction of nickel(I1) and copper(I1) complexes of 4,9-dimethy1-5,8-diazadodeca-4,8diene-2,1 ldione, Ni(baen) and 4,6,9-trimethyl-5, 8diazadodeca-4,8-diene-2,ll-dione, Ni(bapn), with arene diazonium chlorides in buffered solutions of methanol yielded metal derivatives of glyoxaliminearylhydrazones. This typical electrophilic addition at the 3-carbon of the complex occurs owing to the pseudo aromatic behaviour of the chelate ring. A mechanism which predicts the attack of the diazonium cation through the coordination shell of the metal is well documented from the available experimental evidences. The chemical reactivity of a few complexes with a single residual non-substituted y-carbon is reasonably manifested by their reaction with phenyl isocyanate.

An EXAFS study of the cobalt-molybdenum/.gamma.-alumina hydrodesulfurization catalyst

While Mo in the Co-Mo/y-A1203 hydrodesulfurization catalyst is present as a sulfidic species similar to MoS2, Co shows two types of coordination, one with six sulfurs (but not a bulk sulfide) and the other with four oxygens. The significance of such species is discussed. In addition to an additive relation of the EXAFS function and the residual spectra, the ratio of amplitude terms of the catalyst and the model system has been employed in the analysis.

Development and testing of an evaluation procedure for commercial manure additive products.

Manure additive products can be used to reduce odour emissions (OE) from livestock farms. The standardised evaluation of these manure additive products under specific farm conditions is important. In this study, the efficacy of a manure additive (WonderTreat(TM), CKLS, Inc., Hong-Kong) was assessed under Australian conditions utilising a combination of laboratory and field-scale evaluation techniques. As a first step, the efficacy of the manure additive was assessed in a laboratory-scale trial using a series of uniformly managed digesters and standard odour, liquor ammonia and hydrogen sulphide concentration measurement procedures. This showed that the addition of WonderTreat(TM) at the 'low dose rate' (LDR) (102.6 g m-2) used during the trial significantly, but only marginally (30%; P = 0.02) reduced the OE rate (mean 13.9 OU m-2 s-1) of anaerobic pig liquor relative to an untreated control (UC) (19.9 OU m-2 s-1). However, the 'high dose rate' (HDR) (205.3 g m-2) also assessed during the trial preformed similarly (19.7 OU m-2 s-1) to the UC. No statistically significant difference in the concentrations of a range of measured water quality variables at the 5% level was observed between the treatments or controls digesters. As a second step, a field-scale assessment of the manure additive was undertaken at a commercial piggery. Two piggery manure lagoons (each with approximately 2500 m2 surface area) were included in the study; one was treated with WonderTreat(TM) while the other was used as control. The efficacy of the treatment was assessed using olfactometric evaluation of odour samples collected from the surface of the pond using a dynamic wind tunnel and ancillary equipment. No statistically significant reduction in OE rate could be demonstrated (P = 0.35), partially due to the limited number of samples taken during the assessment. However, there was a numerical reduction in the average OE rate of the treatment pond (29 OU m-2 s-1 at 1 m s-1) compared to the control lagoon (38 OU m-2 s-1 at 1 m s-1).

The chemical control of the environmental weed basket asparagus (Asparagus aethiopicus L. cv. Sprengeri) in Queensland

A replicated trial to determine effective chemical control methods for the invasive species, basket asparagus (Asparagus aethiopicus L. cv. Sprengeri) was conducted at Currumbin Hill, Queensland, from June 1999 to August 2000. Four herbicides (metsulfuron-methyl, dicamba, glyphosate and diesel) were applied at different times of the year (winter, spring, summer and autumn). Neat diesel applied to adult crowns effectively killed basket asparagus. However, germination of basket asparagus and other weeds was not prevented. An overall spray of 0.06 g metsulfuron-methyl (0.1 g Brush-Off®) + 1 mL BS 1000® L-1 water gave slower but more selective long-term control of basket asparagus when compared to diesel, especially when applied in winter and spring. High rates of foliar applied dicamba were most effective in spring and glyphosate splatter gunned on base of stems in autumn. The combination of increased selectivity, ease of application and likelihood of reduced environmental impacts on native plants, other than coast she-oak (Casuarina equisetifolia L. var. incana Benth.), of metsulfuron-methyl makes it more suitable for controlling large infestations of basket asparagus.

Kinetics of Chemical Vapor Deposition

A generalized mass transport model is developed for predicting the rate ofdeposition in chemical vapor deposition (CVD) systems. This combines thegeneralized method of obtaining equilibrium composition, with elemental fluxbalance expressions. This procedure avoids the usual problems encountered incalculating the rates in multicomponent systems, like writing overall reactionschemes. The dependence of multicomponent diffusivities on the fluxes is accountedin this model using an iterative procedure. The model developed isapplied to the deposition of titanium carbide on cemented carbide tool bitsfrom a gas mixture of titanium tetrachloride, toluene, and hydrogen. Experimentaldeposition rates were obtained using a thermogravimetric assembly.Mass transport controlled rates give an order of magnitude estimates of theobserved rates.

Chemical aspects of the hypergolic preignition reactions of some hybrid hypergols

A new class of solid compounds, viz., bisthiocarbonohydrazones and thiosemicarbazones, have been found to be hypergolic with fuming nitric acid. The observed ignition delays of these hypergols have been compared with those of the monothiocarbonohydrazones-nitric acid systems and explained in terms of the chemical reactions-neutralization, oxidation, and nitration-occurring in the preignition stage. p-Nitrobenzoic acid, benzoic acid, benzaldehyde, sulfur trioxide, nitrogen dioxide, and nitrogen have been isolated as preignition reaction intermediates in the mono- and bisbenzaldehydethiocarbonohydrazone-nitric acid systems. A scheme of reactions occurring in the preignition stage is proposed based on the formation of these products.

Chemical phytotoxicity testing facility for warm-season turfgrasses

The registration of new agricultural chemicals (particularly herbicides) for turf use requires supporting data on their possible phytotoxic effects across a representative range of turfgrass species and cultivars. This process has been streamlined by the establishment of dedicated phytotoxicity testing site. This facility has enabled phytotoxicity screening of new chemicals to be conducted more quickly, thoroughly and economically than the previous piecemeal ad hoc approach. During the three years of this project, 39 products were screened on the site.

The rα structure, chemical shift anisotropy, and the abnormal orientation of methyldichlorophosphine from the NMR spectrum

NMR studies of methyldichlorophosphine have been undertaken in the nematic phase of mixed liquid crystals of opposite diamagnetic anisotropies. The rα structure is derived. The proton chemical-shift anisotropy has been determined from the studies without the use of a reference compound and without a change of experimental conditions. It is shown that the molecule orients in the liquid crystal with positive diamagnetic anisotropy in such a way that the C3 symmetry axis of the CH3P moiety is preferentially aligned perpendicular to the direction of the magnetic field, unlike other similar systems. This is interpreted in terms of the formation of a weak solvent-solute molecular complex. The heteronuclear indirect spin-spin coupling constants are determined. The sign of the two-bond JPH is found to be positive.

Physio-chemical assessment of beauty leaf (Calophyllum inophyllum) as second-generation biodiesel feedstock

Recently, second-generation (non-vegetable oil) feedstocks for biodiesel production are receiving significant attention due to the cost and social effects connected with utilising food products for the production of energy products. The Beauty leaf tree (Calophyllum inophyllum) is a potential source of non-edible oil for producing second-generation biodiesel because of its suitability for production in an extensive variety of atmospheric condition, easy cultivation, high fruit production rate, and the high oil content in the seed. In this study, oil was extracted from Beauty leaf tree seeds through three different oil extraction methods. The important physical and chemical properties of these extracted Beauty leaf oils were experimentally analysed and compared with other commercially available vegetable oils. Biodiesel was produced using a two-stage esterification process combining of an acid catalysed pre-esterification process and an alkali catalysed transesterification process. Fatty acid methyl ester (FAME) profiles and important physicochemical properties were experimentally measured and estimated using equations based on the FAME analysis. The quality of Beauty leaf biodiesels was assessed and compared with commercially available biodiesels through multivariate data analysis using PROMETHEE-GAIA software. The results show that mechanical extraction using a screw press produces oil at a low cost, however, results in low oil yields compared with chemical oil extraction. High pressure and temperature in the extraction process increase oil extraction performance. On the contrary, this process increases the free fatty acid content in the oil. A clear difference was found in the physical properties of Beauty leaf oils, which eventually affected the oil to biodiesel conversion process. However, Beauty leaf oils methyl esters (biodiesel) were very consistent physicochemical properties and able to meet almost all indicators of biodiesel standards. Overall this study found that Beauty leaf is a suitable feedstock for producing second-generation biodiesel in commercial scale. Therefore, the findings of this study are expected to serve as the basis for further development of Beauty leaf as a feedstock for industrial scale second-generation biodiesel production.

Chemical changes during the aging and decomposition of composite solid propellants

During the thermal decomposition of orthorhombic ammonium perchlorate (AP) at 230°C, where the decomposition is only up to 30 wt %, there is an accumulation in the solid of acids, the concentration of which increases up to 15% decomposition, after which it decreases till it reaches the original value. Similar observations have been made in the polystyrene (PS)/AP propellant systems. Aging studies of PS/AP propellants have been carried out earlier [1], where it has been shown that for the aged propellants the thermal decomposition (TD) rate at 230°C and 260°C and ambient pressure burning rate (Image ) both increase and this increase is due to the formation of reactive intermediate “polystyrene peroxide (PSP).” In the present studies it has been observed that during the aging of the propellant at 150°C, the acid is formed and gets accumulated in the propellant, which may also be responsible for the increase in TD rate and perhaps may be more effective than PSP.

Synthesis and physico-chemical properties of diruthenium(III, II) tetra-aryl carboxylato compounds

Monochloro-tetra-μ-aryl-carboxylatodiruthenium(III, II) compounds Ru2Cl (O2CAr)4 (Ar = -C6H5; -C6H4-p-OCH3), are prepared and characterized. The compounds have magnetic moments that correspond to three unpaired spins per dimer. The Rusingle bondRu bond order is 2.5 and the ground electronic configuration is σ2π4δ2(δ*π*)3. The visible spectral band is observed at ca 450 nm along with a shoulder near 580 nm in DMF solution. The compounds undergo a one-electron Ru(III)Ru(II) → Ru(II)Ru(II) quasi-reversible reduction in DMF near 0.0 V vs sce.

Oriented Nanocrystal Arrays of Selectable Polymorphs by Chemical Sculpture

Growing crystals with selected structure and preferred orientations oil seed substrates is crucial for a wide variety of applications. Although epitaxial or textured film growth of a polymorph whose structure resembles the seed crystal structure is well-known, growing oriented nanocrystal arrays or more than one polymorph, selectable one at a time, from the same seed has not been realized. Here, we demonstrate for the first time the exclusive growth of oriented nanocrystal arrays of two titania polymorphs from a titanate crystal by chemically activating respective polymorph-mimicking crystallographic facets in the seed. The oriented titania nanocrystal arrays exhibit significantly higher photocatalytic activity than randomly oriented polymorphs. Our approach of chemically sculpting oriented nanocrystal polymorph arrays could be adapted to other materials systems to obtain novel properties.

Chlorine-35 Nuclear Quadrupole Resonance Studies in 2,3- and 3,5-Dichloroanisoles

The temperature variation of the 3’Cl n.q.r. frequencies in 3,5- and 2,3- dichloroanisoles has been reported here. Both compounds show two lines each, and these have been assigned to the two chlorines in the same molecule with the help of the additive model for the substituent effect. The temperature dependence has been analysed in terms of Bayer-Kushida-Brown model.The torsional frequencies and their temperature dependence have been calculated numerically under a two-mode approximation. 0.n comparing the results in 3,5-dichloroanisole with those in 3,5-dichlorophenol it can be seen that they show similar behaviour owing to the absence of hydrogen bonding in both.

Extension of Chemical Phytotoxicity Testing Facility for Warm-Season Turfgrasses

The turf industry needs to access a range of more selective, effective and environmentally acceptable pesticides, which will help to address environmental concerns while maintaining the industry's internationally competitive status. This includes both new pesticides being developed globally for turf use and older generic chemicals previously registered for other agricultural purposes and now requiring extension of that registration for use in turf.

Chemical probes into the active centre of a heme thiolate monoxygenase

Linalool-8-monoxygenase, a typical bacterial P-450 heme thiolase, shows a high degree of substrate specificity towards linalool. The active site of the pure enzyme has been probed with a large number of substrate analogues with systematic alterations or conformational variations in the linalool molecule. The comparison of three parameters, the mo→mos conversion of the enzyme as a result of substrate binding monitored at 392 nm, theK D of the analogues giving information about energies of association and the relative turnover as substrate have given information about the space-filling characteristics of the substrates in the enzyme cleft, the number of contacts the molecules make with the respective domains of the enzyme and the distance of the site undergoing hydroxylation from the oxygen site, respectively. The data permit the conclusion that linalool makes contact with the enzyme by hydrogen bonding with the hydroxyl group as well through hydrophobic association with all the eight carbons carrying hydrogen in the molecules.