A facile and green route to terpene derived acrylate and methacrylate monomers and simple free radical polymerisation to yield new renewable polymers and coatings

We present new acrylic monomers derived directly from abundant naturally available terpenes via a facile, green and catalytic approach. These monomers can be polymerised to create new polymers with a wide range of mechanical properties that positions them ideally for application across the commodity and specialty plastics landscape; from packaging, cosmetic and medical, through to composites and coatings. We demonstrate their utility through formation of novel renewable polymer coatings

Unexpectedly high barriers to M–P rotation in tertiary phobane complexes : PhobPR behavior that is commensurate with tBu2PR

The four isomers of 9-butylphosphabicyclo[3.3.1]nonane, s-PhobPBu, where Bu = n-butyl, sec-butyl, isobutyl, tert-butyl, have been prepared. Seven isomers of 9-butylphosphabicyclo[4.2.1]nonane (a5-PhobPBu, where Bu = n-butyl, sec-butyl, isobutyl, tert-butyl; a7-PhobPBu, where Bu = n-butyl, isobutyl, tert-butyl) have been identified in solution; isomerically pure a5-PhobPBu and a7-PhobPBu, where Bu = n-butyl, isobutyl, have been isolated. The σ-donor properties of the PhobPBu ligands have been compared using the JPSe values for the PhobP(═Se)Bu derivatives. The following complexes have been prepared: trans-[PtCl2(s-PhobPR)2] (R = nBu (1a), iBu (1b), sBu (1c), tBu (1d)); trans-[PtCl2(a5-PhobPR)2] (R = nBu (2a), iBu (2b)); trans-[PtCl2(a7-PhobPR)2] (R = nBu (3a), iBu (3b)); trans-[PdCl2(s-PhobPR)2] (R = nBu (4a), iBu (4b)); trans-[PdCl2(a5-PhobPR)2] (R = nBu (5a), iBu (5b)); trans-[PdCl2(a7-PhobPR)2] (R = nBu (6a), iBu (6b)). The crystal structures of 1a–4a and 1b–6b have been determined, and of the ten structures, eight show an anti conformation with respect to the position of the ligand R groups and two show a syn conformation. Solution variable-temperature 31P NMR studies reveal that all of the Pt and Pd complexes are fluxional on the NMR time scale. In each case, two species are present (assigned to be the syn and anti conformers) which interconvert with kinetic barriers in the range 9 to >19 kcal mol–1. The observed trend is that, the greater the bulk, the higher the barrier. The magnitudes of the barriers to M–P bond rotation for the PhobPR complexes are of the same order as those previously reported for tBu2PR complexes. Rotational profiles have been calculated for the model anionic complexes [PhobPR-PdCl3]− using DFT, and these faithfully reproduce the trends seen in the NMR studies of trans-[MCl2(PhobPR)2]. Rotational profiles have also been calculated for [tBu2PR-PdCl3]−, and these show that the greater the bulk of the R group, the lower the rotational barrier: i.e., the opposite of the trend for [PhobPR-PdCl3]−. Calculated structures for the species at the maxima and minima in the M–P rotation energy curves indicate the origin of the restricted rotation. In the case of the PhobPR complexes, it is the rigidity of the bicycle that enforces unfavorable H···Cl clashes involving the Pd–Cl groups with H atoms on the α- or β-carbon in the R substituent and H atoms in 1,3-axial sites within the phosphabicycle

Emissions of methyl chloroform (CH3CCl3) from biomass burning and the tropospheric methyl chloroform budget

The only known sources of atmospheric methyl chloroform are industrial production and biomass burning. With the phase‐out of industrial methyl chloroform production the atmospheric burden of methyl chloroform is rapidly declining. Consequently the potential importance of nonindustrial sources is increasing. Up to now only one experimental investigation of methyl chloroform emissions from biomass burning has been published. Here laboratory studies of methyl chloroform emission from wood burning are presented. The emission ratios relative to carbon dioxide and carbon monoxide are 12.7 ± 2.6 × 10−8 and 15.6 ± 3.3 × 10−7, respectively. Although based on a limited number of measurements, they strongly suggest that methyl chloroform emissions from biomass burning are at the lower end of previous estimates. The impact of these emissions on the chemistry of the atmosphere will be marginal. However, reliable knowledge of the biomass burning source strength will be essential for a detailed analysis of the trend of atmospheric methyl chloroform concentrations

A review of biomass burning emissions, part I: gaseous emissions of carbon monoxide, methane, volatile organic compounds, and nitrogen containing compounds

International audienceBiomass burning is the burning of living and dead vegetation. Ninety percent of all biomass-burning events are thought to be human initiated. Human induced fires are used for a variety of ''applications'' such as agricultural expansion, deforestation, bush control, weed and residue burning, and harvesting practices. Natural fires are grassland and forest fires mainly induced by lightning. It is estimated that 8700 Tg of dry matter/year are burnt each year in total. Emissions from biomass burning include a wide range of gaseous compounds and particles that contribute significantly to the tropospheric budgets on a local, regional, and even global scales. The emission of CO, CH4 and VOC affect the oxidation capacity of the troposphere by reacting with OH radicals, and emissions of nitric oxide and VOC lead to the formation of ozone and other photo oxidants. For a large number of compounds biomass burning is one of the largest single sources in the troposphere, especially in the tropics. Biomass-burning emissions play an important role in the biogeochemical cycles of carbon and nitrogen. Following the first systematic investigations on fire emissions in laboratory experiments in the 1960's, the last 20 years saw an increasing number in studies on biomass-burning emissions in various ecosystems. Recently, our knowledge of the emissions of gaseous compounds in the troposphere from fires has increased considerably. This manuscript is the first of four describing the properties biomass burning emissions. The properties of biomass-burning particles are discussed in part II and III of this review series which have been recently published, and their direct radiative effects are in part IV. This paper focuses on the review of emission ratios and emission rates of carbon monoxide, methane, volatile organics, and nitrogen containing compounds and should not be seen as a review of global emission estimates, even though we discuss the implications of our results on such studies