Jurgen Korth

Novel technique shows different hydrophobic chemical signatures of exotic and indigenous plant soils with similar effects of extracts on indigenous species seedling growth

Changes to ecosystem abiotic parameters are regarded as possible mechanisms facilitating plant invasion and community composition shifts. This study compared the hydrophobic chemical signatures of soil from exotic bitou bush (Chrysanthemoides monilifera spp. rotundata) invaded, indigenous acacia (Acacia longifolia var. sophorae) dominated and bare sand (unvegetated) habitats using a novel, rapid, capturing technique which utilised Amberlite® XAD4 resin filled bags that were placed in situ. The hydrophobic chemical signature of the bitou bush soil extract was significantly different to the acacia soil and bare sand extracts. High concentrations of 18 sesquiterpenes dominated the hydrophobic signature of the bitou bush extract. Low concentrations of all three extracts did not significantly affect the seedling growth of three indigenous test species under laboratory conditions, however, at higher concentrations, the extracts from soil inhabited by plants, whether exotic or indigenous, similarly inhibited the seedling growth of two species, while seedling growth of the third species was inhibited by extracts from all three soil types. These results do not support the hypothesis that exotic invasive species are more likely to exhibit allelopathic effects than indigenous plant species.

Chemical class separation of shale oils by low pressure liquid chromatography on thermally-modified adsorbants☆

Abstract Shale oils from Green River (USA) and Condor (Australia) were fractionated into compound classes by low pressure liquid chromatography on five columns in series containing successively less thermally-deactivated grades of alumina. No preliminary acidic and basic extractions were required, resulting in fewer polymeric artefacts than in other procedures. Irreversible adsorptive losses were minimized by the use of deactivated adsorbants and evaporative losses were minimized by the use of highly volatile solvents and small solvent volumes. Compounds identified include linear alkanes, isomeric linear alkenes, isoprenoid alkanes and alkenes, linear alkanonitriles, 2-, 3- and 4-alkenones, cyclopentanones, cyclohexanones, benzenes, styrenes, indans, indenes, 1-phenylalk-1-enes, naphthalenes, biphenyls, 3–5 ring aromatics, phenols, pyridines, quinolines, benzoquinolines, indoles, dihydroindoles and carbazoles. Particular compound classes may be isolated without performing a full chromatographic separation of all classes.

Removal of nitrogen compounds from hydrotreated shale oil by adsorption on zeolite

Abstract US-Y zeolite was used to adsorb eight aromatic nitrogen compounds dissolved in hexane, hexane + hexadecane, hexane + naphthalene and hexane + hydrotreated shale oil. The total N concentration in an unspiked hydrotreated shale oil was reduced from 2000 to a few ppmw. The adsorbed N compounds were removed from the zeolite by combustion, allowing the zeolite to be reused. Zeolite adsorption may be used instead of severe hydrotreatment to remove residual nitrogen compounds.

Heterogeneous reactions of 1-pristene catalysed by clays under simulated geological conditions

Abstract 1-Pristene was chemisorbed by evaporation from pentane solution on kaolinite, illite, bentonite and solvent-extracted Condor oil shale, and maintained at 25–150°C for 0.5–900 h. The reaction products were extracted from the clay with dichloromethane and were identified by GC, GC-MS and 1H-n.m.r. At 25°C and 50°C, the main reactions of 1-pristene with kaolinite are double bond isomerisation to 2-pristene and hydration to 2-pristanol. Under identical conditions, linear alkenes aer unaffected. At 75°C, the double bond migrates further to yield additionally 5-pristene, 6-pristene and 6-pristanol. Above 100°C, hydrogen transfer occurs to produce pristane by an unknown mechanism and, above 150°C, this pathway predominates with pristanols now present as minor components. Illite was a less active catalyst than kaolinite for dehydration, hydrogenation and cracking at 100–150°C. The order of catalytic activity for 1-pristene transformation by air dried mineral at 25°C was: kaolinite ∼ illite > pyrite > calcite > bentonite > quartz. Air dried kaolinited becomes more active when surface water is partly removed by heating to 100°C. The product distribution depends on the activity of the clay, the ratio of 1-pristene to clay, the temperature and the reaction time. The results provide evidence for a clay-mediated pathway from 1-pristene to pristane under some geological conditions.

Chemical characterization of shale oil from Duaringa, Australia

Abstract Shale oil from the upper and lower units of the Duaringa deposit at Duaringa, Queensland, was chemically separated into 23 fractions and analysed by g.c.-m.s. Over 700 compounds were identified, including homologous series of linear alkanes, 2-, 3-, 4- and 5-methylalkanes, isoprenoid hydrocarbons, alkylcyclopentanes, alkylcyclohexanes, 1-, 2-, 3- and 4-alkenes, alkylcyclohexenes, alkylcyclopentenes, linear dienes, alkylbenzenes, alkylmethylbenzenes, alkyldimethylbenzenes, alkyltrimethylbenzenes, alkylindans, alkylnaphthalenes, nitriles, 2-, 3-, 4- and 5-alkanones. Substituted cyclopentanes, cyclohexanes, benzenes, naphthalenes, polycyclic aromatic hydrocarbons, phenols, carboxylic acids, pyridines, dihydroindoles, quinolines and tetrahydroquinolines were also identified. The oils were highly aliphatic ( H C = 1.67–1.75 ), with alkanes (24–29%), alkenes (13–14%), aromatic hydrocarbons (23–25%), alkadienes (2.5%), nitriles (1–1.5%) and alkanones (0.6%) being the most abundant volatile components of the neutral fraction of the oils. The two oils were very similar, but some differences suggested that the mineral matrix of the upper unit was more active in promoting secondary pyrolytic reactions. As measured by retort oil composition, the lower unit (depth > 1000 m) was no more mature than the upper unit. A simple experimental procedure based on solution density was used for rapid quantitation of the neutral oil fraction without loss of volatiles.

Low temperature pyrolysis of three Tertiary oil shales from Queensland, Australia: A comparative chemical and petrographic study

Etude des changements chimiques et petrographiques lors de la pyrolyse a 350 o C des schistes bitumineux Rundle, Stuart et Condor

Treatment of retort waters from Stuart oil shale using high-silica zeolites

Abstract High-silica zeolites (US-Y and ZSM-5) were used to adsorb organics from retort waters derived from Stuart oil shale (Queensland, Australia). Removal of organics increased with decreasing polarity of the adsorbate and improved when free ammonia was removed first by air stripping. Zeolites were more effective than activated carbon. They are easily regenerated and are potential agents for pretreatment for retort waters before biological treatment.

A comparison of microscale pyrolysis and organic petrography for the estimation of yield from oil shale

Abstract A Control Data System CDS 150 pyroprobe was modified to operate in either a flash pyrosis or programmed temperature (pyrolysis-FID) mode. The latter simulated Fischer Assay (FA) retort conditions and gave total gas and oil yields which correlated with FA, organic petrography, kerogen content and elemental analysis for 21 Australian and 5 overseas oil shales. The pyrolysis-FID (py-FID) data obtained for the well-characterised overseas oil shales, containing kerogens of known type, allowed the Australian shales to be grouped into three production grades according to the relative conversion of their constituent kerogens. For grade 1 and grade 2 shales, specific oil yields were closely linked to the type and abundances of the maceral groups and were virtually unaffected by wide variations in mineral content and composition. Oil yields was related to maceral volume per cent using both quadratic and linear functions. The inherent limitations of petrographic data meant that a linear equation fitted the data almost as well as the quadratic equation required by theory. The py-FID procedure predicted FA yields more accurately than did organic petrography for the entire range of kerogen content (4–82%) provided a finely ground, representative sample was taken.

The Chemical Constituents and the Cytotoxicity, Antioxidant and Antibacterial Activities of the Essential Oil of Graptophyllum pictum (L.) Griff.

Abstract The essential oil from the leaves of Graptophyllum pictum (L.) Griff. was isolated by hydrodistillation and its chemical constituents were investigated by a combination of gas chromatographic (GC-FID) and gas chromatography-mass spectrometric (GC-MS) analysis. Fourteen compounds, comprising 95.0 % of the gas chromatographical oil, were identified. The major constituents were phytol (75.7 %), n-nonacosane (6.5 %) and hexahydrofarnesyl acetone (2.6 %). The oil showed significant cytotoxicity against KB (epidermoid carcinoma of oral cavity), NCI-H187 (small cell lung carcinoma) and Vero cell lines with IC50 values of 27.04, 25.27 and 26.52 µg/mL, respectively. The antioxidant activity of the oil was determined using the ABTS radical cation scavenging assay. The oil had less antioxidant activity than the controls, trolox and ascorbic acid. In a disc diffusion assay the oil exhibited antibacterial activity against S. aureus and E. coli with MIC values of 11.75 and 35.25 µg/disc, respectively.

The Chemical Constituents and Biological Activities of the Essential Oil and the Extracts from Leaves of Gynura divaricata (L.) DC. Growing in Thailand

Abstract The chemical constituents of the essential oil from the leaves of Gynura divaricata (L.) DC. were investigated by GC-FID and GC-MS. Seventeen compounds, representing 97.1 % of the chromatographical fraction of the oil, were detected. The major constituents, cubenol (65.7 %) and spathulenol (6.4 %), were isolated using column chromatography and identified by NMR and MS analysis. The antioxidant, cytotoxicity and antimicrobial activities of the essential oil, the hexane, dichloromethane and methanol extracts of G. divaricata leaves were investigated. The essential oil and the crude extracts showed antioxidant activity using the ABTS and DPPH methods, respectively. The essential oil exhibited significant cytotoxicity against KB, MCF-7 and NCI-H187 cancer cell lines with the IC values of 5.79, 47.44 and 17.65 µg/mL, respectively and had a MIC of 50 μg/mL against Mycobacterium tuberculosis H37Ra. Cubenol had an IC50 value of 45.37 µg/mL against the NCI-H187 cancer cell line. All extracts were non-cytotoxic against Vero cells. The essential oil and the extracts showed antimicrobial activity using the disc diffusion assay. The methanol extract was the most potent of the three extracts.