Antonio F. Patti

Extraction of lignin from lignocellulose at atmospheric pressure using alkylbenzenesulfonate ionic liquid

Lignocellulosic materials are a potentially valuable source of both aromatic compoundsvia the lignin component and sugars from the cellulose and hemicellulose components. However, efficient means of separating and depolymerising the components are required. An ionic liquid mixture containing the 1-ethyl-3-methylimidazolium cation and a mixture of alkylbenzenesulfonates with xylenesulfonate as the main anion was used to extract lignin from sugarcane plant waste at atmospheric pressure and elevated temperatures (170–190 °C). The lignin was recovered from the ionic liquid by precipitation, allowing the ionic liquid to be recycled. An extraction yield exceeding 93% was attained. The lignin produced had a molecular weight of 2220 g/mol after acetylation. The regenerated ionic liquid showed good retention of structure and properties. The other product of the extraction was a cellulose pulp, which can be used in further processing.

Assessing and improving the catalytic activity of K-10 montmorillonite

K-10 montmorillonite, commonly used as a heterogeneous acid catalyst, was found to vary in the extent of acid-treatment, with some batches exhibiting significantly reduced catalytic activity in Bronsted acid-catalysed reactions. K-10 was thus further treated with HCl of varying concentrations to increase its activity in acid-catalysed reactions. Acid-treated clays exhibited significant enhancements in catalytic activity in three test reactions; tetrahydropyranylation of ethanol, diacetylation of benzaldehyde and esterification of succinic anhydride. Acid-treatment of K-10 was shown to result in protonation, and loss of layer stacking of the clay structure, as determined by powder X-ray diffraction, inductively coupled plasma–optical emission spectroscopy (ICP-OES), diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy and Brunauer–Emmett–Teller (BET) specific surface area measurements. Quantifiable physical changes to the K-10 correlated with measurable increases in catalytic activity. Standard procedures for assessing acid-treated montmorillonite clay catalysts, such as K-10, and procedures for obtaining the most effective catalyst for acid-catalysed reactions, involving analytical and synthetic techniques, were devised.

Physicochemical and microbiological effects of long- and short-term winery wastewater application to soils

Application of winery wastewaters to soils for irrigation of various crops or landscapes is a common practice in the wine industry. In this study, we sought to investigate the effects of this practice, by comparing the physicochemical and microbiological soil properties in paired sites that differed in having had a history of winery waste application or not. We also compared the effects of a single application of untreated winery wastewater, to application of treated winery wastewater (sequencing batch reactor) and pure water to eliminate the effects of wetting alone. Long-term application of winery wastes was found to have significant impacts on soil microbial community structure, as determined by phospholipid fatty acid analysis, as well as on many physicochemical properties including pH, EC, and cation concentrations. (13)C NMR revealed only slight differences in the nature of the carbon present at each of the paired sites. A single application of untreated winery wastewater was shown to have significant impacts upon soil respiration, nitrogen cycling and microbial community structure, but the treated wastewater application showed no significant differences to wetting alone. Results are discussed in the context of sustainable winery wastewater disposal.

Winery wastewater inhibits seed germination and vegetative growth of common crop species.

The ability to reuse winery wastewater would be of significant benefit to the wine industry, as it could potentially be a cost-effective method of wastewater management, whilst at the same time providing a valuable water resource. This study investigated the effects of different dilutions of a semi-synthetic winery wastewater on the growth and germination of four common crop species in a glasshouse study; barley (Hordeum vulgare), millet (Pennisetum glaucum), lucerne (Medicago sativa) and phalaris (Phalaris aquatica). The wastewater caused a significant delay in the germination of lucerne, millet and phalaris, although overall germination percentage of all species was not affected. Vegetative growth was significantly reduced in all species, with millet being the most severely affected. The germination index of barley correlated very highly (r(2)=0.99) with barley biomass, indicating that barley seed germination bioassays are highly relevant to plant growth, and therefore may be of use as a bioassay for winery wastewater toxicity.

Oxidative coupling revisited: solvent-free, heterogeneous and in water

Fe(III) treated K-10 montmorillonite and FeCl3 (both hydrated and anhydrous) are compared as catalysts for oxidative coupling of phenol substrates under a range of conditions. While the commonly reported coupling of 2-naphthol proceeds under a range of conditions, other substrates are far less readily coupled. Counterintuitively, biphasic reactions of poorly water soluble substrates in contact with aqueous solutions of FeCl3 are the most universally applicable conditions while many homogeneous reaction mixtures yield little or no coupling product. Fe(III) treated K-10 proved to be a poor catalyst for oxidative coupling of most substrates. Comparison of coupling conditions provides a framework for optimisation of green methodologies using oxidative coupling catalysts.

ORGANIC AMENDMENTS INCREASE SOIL SOLUTION PHOSPHATE CONCENTRATIONS IN AN ACID SOIL : A CONTROLLED ENVIRONMENT STUDY

Soil acidification affects at least 4 million hectares of agricultural land in Victoria, Australia. Low soil pH can inhibit plant growth through increased soluble aluminum (Al) concentrations and decreased available phosphorus (P). The addition of organic amendments may increase P availability through competition for P binding sites, solubilization of poorly soluble P pools, and increased solution pH. The effect of two organic amendments (lignite and compost) on P solubility in an acid soil was determined through controlled environment (incubation) studies. Three days after the addition of lignite and compost, both treatments increased orthophosphate and total P measured in soil solution, with the compost treatments having the greatest positive effect. Increased incubation time (26 days) increased soil solution P concentrations in both untreated and amended soils, with the greatest effect seen in total P concentrations. The measured differences in solution P concentrations between the lignite- and compost-amended treatments were likely caused by differences in solution chemistry, predominantly solution pH and cation dynamics. Soil amendment with lignite or compost also increased microbial activity in the incubation systems, as measured by carbon dioxide respiration. Based on the results presented, it is proposed that the measured increase in soil solution P with amendment addition was likely caused by both chemical and biological processes, including biotic and abiotic P solubilization reactions, and the formation of soluble organic-metal complexes.

Partial Exchange of Fe(III) Montmorillonite with Hexadecyltrimethylammonium Cation Increases Catalytic Activity for Hydrophobic Substrates

Fe(III) montmorillonite clay that was partially exchanged with hexadecyltrimethylammonium (HDTMA(+)) cations achieved increased catalytic activity for the oxidative coupling of hydrophobic organic substrates. A series of mixed-cation organoclays were produced, where the organic cation content ranged from 6 to 50% relative to the cation-exchange capacity (CEC) of the clay, and were tested for catalytic activity using different Fe(III)-mediated oxidative coupling reactions. Enhanced catalytic activity by Fe(3+)/HDTMA(+) montmorillonite for coupling hydrophobic substrates was observed, with maximum catalytic activity in the oxidative coupling of 2-naphthol observed at 6% HDTMA(+) coverage. However, maximum catalytic activity with a more hydrophobic substrate, anthrone, was achieved with 50% HDTMA(+) coverage, indicating that matching levels of organic modification to substrate hydrophobicity improves catalytic activity. The organization of the organic cations at the clay surfaces proved to be heterogeneous, as determined by scanning transmission X-ray microscopy (STXM) and powder X-ray diffraction. Results from molecular dynamics simulations supported the heterogeneous nature of the catalysts but also pointed toward large regions within the interlayers that may be filled with nonreactive hydrated Fe oxides resulting from the organic cation treatment. The exchangeable Fe content of the organic treated clays, as determined by AAS and ICP measurements, was observed to be higher than expected relative to that of Fe-saturated clay, substantiating this hypothesis. These findings have implications for the development of substrate-specific clay catalysts, where the composition and configuration of exchangeable cations can be matched to a particular substrate or reaction.

Soil amendments modify phosphate sorption in an acid soil: the importance of P source (KH2PO4, TSP, DAP)

Soil acidity is a widespread problem in Victoria, Australia, affecting at least 4 million ha of agricultural land. Soil amendments such as lime and organic materials may ameliorate acid soils, resulting in raised soil pH and increased availability of plant nutrients such as phosphorus (P). The addition of lime, lignite, and compost significantly modified P sorption in an acid soil, with the degree of change highly dependent upon the source of P applied. The application of 2.5u2009t/ha of lime increased P sorption for all P sources, while P sorption was decreased in the lignite and compost treatments when di-ammonium phosphate (DAP) was applied. Lime and compost addition increased the solution pH, with no change in pH in the lignite treatment. Addition of TSP decreased the pH in all treatments, while DAP addition only increased solution pH in the untreated soil and the lignite treatment. The addition of soil amendments had a significant effect on solution cation concentrations, due to both the influx of cations, and the resultant changes in solution pH. The source of P applied (KH2PO4, TSP (triple superphosphate), DAP) also had a significant effect due to both the counter-ions present and the pH of each P source (e.g. TSP pH 2.7; DAP pH 7.4). The lignite treatment decreased total P sorption relative to the other amendments. The combination of lignite and DAP resulted in both the greatest decrease in P sorption, and the formation of soluble Al–organic complexes. Therefore, a combination of lignite and DAP may be of use in decreasing P sorption in acid soils.

A direct route to medium and large cyclic amines from aminoalkenes

Abstract Rhodium-catalysed reactions of aminoalkenes with H 2 /CO give cyclic amines with a range of medium and large ring sizes in yields up to 85%. High regioselectivity for non-branched products can be obtained when BIPHEPHOS is used as a ligand in the hydroformylation reaction.

Profiling of soil fatty acids using comprehensive two-dimensional gas chromatography with mass spectrometry detection.

Profiling of phospholipid fatty acids (PLFA) represents a challenging goal for distinguishing the diversity of microbial communities and biomass in the complex and heterogeneous soil ecosystem. Comprehensive two-dimensional gas chromatography (GC×GC) coupled with simultaneous flame ionisation and mass spectrometry detection was applied as a culture-independent method for PLFA profiling of microbial classification in forest soil. A number of column sets were evaluated for the GC×GC separation of fatty acid methyl esters (FAME). Due to better isomeric separation and compound patterns on the 2D contour plot, an apolar-polar column combination was selected for soil microbial PLFA characterisation. A comprehensive view of PLFA composition with carbon chain length varying from 12 to 20 was observed in forest soil samples, with the commonly reported bacterial FAME of iso-/anteiso-, methyl-branched-, cyclopropyl-, and hydroxyl-substituted FA identified by their mass spectral and retention time according to authentic standards. Notably, some uncommon oxygenated FAME were found in high abundance and were further characterised by GC×GC coupled with high resolution mass spectrometry. This tentatively revealed geometric pairs of methyl 9,10-epoxyoctadecanoate isomers.