Chemistry on the inside: green chemistry in mesoporous materials

An overview of the rapidly expanding area of tailored mesoporous solids is presented. The synthesis of a wide range of the materials is covered, both inorganically and organically modified. Their applications, in particular those relating to green chemistry, are also highlighted. Finally, potential future directions for these materials are discussed

Catalytic performance of carbonaceous materials in the esterification of succinic acid

Mesoporous carbonaceous materials have outstanding potential in many different applications such as adsorption, medicine and catalysis. We have recently reported the synthesis of a new form of mesoporous carbon, named Starbon((R)), obtained after low temperature carbonization of expanded starch. Such starch-derived mesoporous materials have several tunable properties including surface energies (ranging from hydrophilic to hydrophobic surfaces), which can be easily controlled by the degree of carbonization (from 200 to 700 degrees C). Due to the diversity of surface functional groups, Starbons((R)) can be easily chemically modified. Treatment of Starbon((R)) materials with sulfuric acid gave a solid acid that has promising properties as heterogeneous catalyst. Comparative catalytic studies with some other similar commercial carbonaceous materials such as DARCO((R)) and NORIT (R), as well as phosphorous-containing microporous carbons, are reported. (c) 2008 Elsevier B.V. All rights reserved

Scientific Note: Update on the establishment of birch leafminer parasitoids in western Canada

submitted as scientific note, no abstract

Effect of spruce-derived phenolics extracted using microwave enhanced pyrolysis on the oxidative stability of biodiesel

An investigation has been carried out to characterize and evaluate phenolic compounds of bio-oils produced by the microwave enhanced pyrolysis of spruce woodchips (picea abies) for their potential application in stabilizing biodiesel from autoxidation. Four extracts were isolated from the bio-oil through multi-fractionation steps using a liquid-liquid extraction method: water-soluble, neutral, phenolic and organic acids extracts. The crude bio-oil and the isolated extracts were characterized by GC-MS, GC-FID, total phenols by Folin-Ciocalteu assay, ATR-IR and 13C NMR. The antioxidative effect of the crude bio-oil, its isolated extracts and two significant phenolic components (eugenol and catechol) of the crude bio-oil were also investigated using methyl linoleate as a biodiesel model by means of a high temperature (120°C) oxidation test. The results show that methyl linoleate induction time increased after blending small amounts (1.4-5.6% w/w) of either the crude bio-oil or the isolated extracts. However, the crude bio-oil showed higher induction times in comparison with its isolated extracts, which was significant because the crude bio-oil contained a lower concentration of phenolic species (23% w/w), especially in comparison to the phenolic concentration in the phenolic extract (49.6% w/w). Furthermore, catechol was found to be very effective and was similar to crude bio-oil in the inhibition of methyl linoleate autoxidation, unlike eugenol, which was less effective at equivalent molar concentrations. Also, the effect of catechol and the crude bio-oil on methyl linoleate induction time was approximately comparable with a commercial antioxidant (butylated hydroxytoluene) when treated at equivalent molar concentration of phenols

The Impact of Domestic Violence in the Workplace: Results from a Pan-Canadian Survey

When workers experience domestic violence (DV) at home, impacts are felt in the workplace; however, little research is available on this topic. Methods: We conducted an online survey regarding the impacts of DV at work. Results: A total of 8429 people completed the survey. More than a third of respondents reported experiencing DV; among them, more than a third reported that DV affected their ability to get to work, and more than half reported that it continued at or near work. Most reported that DV negatively affected their performance. Almost all respondents, regardless of DV experience, believed that it impacts victims\u27 work lives. Conclusions: This research identifies the scope and impact of DV on workers and workplaces. The data should assist governments, unions, and employers to enact and evaluate proactive practices to address the impact of DV in the workplace

Post-polymerisation modification of bio-derived unsaturated polyester resins via Michael additions of 1,3-dicarbonyls

Post-polymerisation modification of α,β-unsaturated polyesters (UPEs) is useful to deliver polymers with tuneable properties and applications different from their parent backbone. Bio-derivable itaconate unsaturated polyesters, with a range of co-monomers, were modified via a heterogeneously catalysed microwave-assisted Michael addition of pendants, acetylacetone (Hacac) and dimethyl malonate (DMM), to the polymer backbones with very short reaction times. Differential scanning calorimetry analysis showed an increase in the glass-transition temperatures of most of the saturated polyesters considered. Solubility and complexation studies demonstrated metal chelating abilities of the acetylacetone pendant can be retained, even following tethering to a polyester backbone. Additionally, it is demonstrated for the first time that Michael addition with Hacac and DMM can be used to reverse Ordelt saturation, an unwanted side-reaction in the synthesis of UPEs

P-cymenesulphonyl chloride : A bio-based activating group and protecting group for greener organic synthesis

A bio-derived protecting/activating group has been synthesized by introducing a sulphonyl chloride group to the aromatic ring of p-cymene derived from citrus peel waste. The resulting p-cymenesulphonyl chloride was evaluated as an activating group by reacting with 1-octanol, 2-octanol, phenol and piperidine, and further reactions of the activated alcohols. The comparison to tosyl chloride demonstrates that the bio-based alternative can be effectively utilized as a direct replacement for the current fossil derived equivalent

Work-hardening Photopolymer from Renewable Photoactive 3,3’-(2,5-Furandiyl)bisacrylic Acid

The design of a photopolymer around a renewable furan-derived chromophore is presented herein. An optimised semi-continuous oxidation method using MnO2 affords 2,5-diformylfuran from 5-(hydroxymethyl)furfural in gram quantities, allowing the subsequent synthesis of 3,3’-(2,5-furandiyl)bisacrylic acid in good yield and excellent stereoselectivity. The photoactivity of the diester of this monomer is confirmed by reaction under UV irradiation, and the proposed [2+2] cycloaddition mechanism supported further by TD-DFT calculations. Oligoesters of the photoreactive furan diacid with various aliphatic diols are prepared via chemo- and enzyme-catalysed polycondensation. The latter enzyme-catalysed (Candida antarctica lipase B) method results in the highest Mn (3.6 kDa), suggesting milder conditions employed with this protocol minimised unwanted side reactions, including untimely [2+2] cycloadditions, whilst preserving the monomer's photoactivity and stereoisomerism. The photoreactive polyester is solvent cast into a film where subsequent initiator-free UV curing leads to an impressive increase in the material stiffness, with work-hardening characteristics observed during tensile strength testing

Synthesis and application of tuneable carbon-silica composites from the microwave pyrolysis of waste paper for selective recovery of gold from acidic solutions

Microwave pyrolysis bio-oil from waste paper and K60 silica gel has successfully been utilised to synthesise mesoporous carbon-silica composites with uniquely tuneable surface properties, where functionality and structural characteristics can be altered and even enhanced by curing at different temperatures. This temperature-dependence resulted in composites ranging from highly oxygenated polymerised bio-oil composites at 300 °C to aromatic carbonaceous materials covering the silica surface at 800 °C, making them attractive materials for gold recovery from mining wastewater. The composite materials exhibit exceptional ability and selectivity to recover gold from dilute solutions. Metal adsorption on the surface of these composites proceeded via both chemisorption and physisorption leading to the reduction of Au(iii) to Au(0), resulting in high recovery capacities for gold. Composite material prepared at 500 °C demonstrated the optimum combination of surface functionality and porosity, allowing for an adsorption capacity of 320 mg g-1 of gold and with 99.5% removal being achieved at concentrations mimicking those of real-life mine tailing wastes. All materials pioneered in this research display great potential as selective adsorbents for the recovery of gold from acidic media. This journal i