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1.
Evidence for organic synthesis in high temperature aqueous media — Facts and prognosis 总被引:2,自引:0,他引:2
Bernd R. T. Simoneit 《Origins of life and evolution of the biosphere》1995,25(1-3):119-140
Hydrothermal systems are common along the active tectonic areas of the earth. Potential sites being studied for organic matter alteration and possible organic synthesis are spreading ridges, off-axis systems, back-arc activity, hot spots, volcanism, and subduction. Organic matter alteration, primarily reductive and generally from immature organic detritus, occurs in these high temperature and rapid fluid flow hydrothermal regimes. Hot circulating water (temperature range — warm to >400 °C) is responsible for these molecular alterations, expuslion and migration. Compounds that are obviously synthesized are minor components because they are generally masked by the pyrolysis products formed from contemporary natural organic precursors. Heterocyclic sulfur compounds have been identified in high temperature zones and hydrothermal petroleums of the Guaymas Basin vent systems. They can be interpreted as being synthesized from formaldehyde and sulfur or HS
x
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in the hydrothermal fluids.Other products from potential synthesis reactions have not yet been found in the natural systems but are expected based on known industrial processes and inferences from experimental simulation data. Various industrial processes have been reviewed and are of relevance to hydrothermal synthesis of organic compounds. The reactivity of organic compounds in hot water (200–350 °C) has been studied in autoclaves, and supercritical water as a medium for chemistry has also been evaluated. This high temperature aqueous organic chemistry and the strong reducing conditions of the natural systems suggest this as an important route to produce organic compounds on the primitive earth. Thus a better understanding of the potential syntheses of organic compounds in hydrothermal systems will require investigations of the chemistry of condensation, autocatalysis, catalysis and hydrolysis reactions in aqueous mineral buffered systems over a range of temperatures from warm to >400 °C.Presented in part at the International Society for the Study of the Origin of Life Meeting, Barcelona, Spain, July 1993. 相似文献
2.
The covalently bonded components of the stem cutin of Psilotum include 16-hydroxyhexadecanoic acid and substantial amounts of hexadecane-1,8,16-triol. While of generally similar composition, leaf cutin of Tmesipteris contains a mixture of hexadecanetriol isomers. The findings suggest that psilotophyte cutins evolved in a different manner from those of other land plants. 相似文献
3.
Abdulaziz S. Alqarni Ahmed I. Rushdi Ayman A. Owayss Hael S. Raweh Aarif H. El-Mubarak Bernd R. T. Simoneit 《PloS one》2015,10(6)
Propolis is a gummy material produced by honey bees to protect their hives and currently has drawn the attention of researchers due to its broad clinical use. It has been reported, based only on observations, that honey bees also collect other non-vegetation substances such as paint or asphalt/tar to make propolis. Therefore, propolis samples were collected from bee hives in Riyadh and Al-Bahah, a natural area, Saudi Arabia to determine their compositional characteristics and possible sources of the neutral organic compounds. The samples were extracted with hexane and analyzed by gas chromatography-mass spectrometry. The results showed that the major compounds were n-alkanes, n-alkenes, methyl n-alkanoates, long chain wax esters, triterpenoids and hopanes. The n-alkanes (ranging from C17 to C40) were significant with relative concentrations varying from 23.8 to 56.8% (mean = 44.9+9.4%) of the total extracts. Their odd carbon preference index (CPI) ranged from 3.6 to 7.7, with a maximum concentration at heptacosane indicating inputs from higher plant vegetation wax. The relative concentrations of the n-alkenes varied from 23.8 to 41.19% (mean = 35.6+5.1%), with CPI = 12.4-31.4, range from C25 to C35 and maximum at tritriacontane. Methyl n-alkanoates, ranged from C12 to C26 as acids, with concentrations from 3.11 to 33.2% (mean = 9.6+9.5%). Long chain wax esters and triterpenoids were minor. The main triterpenoids were α- and β-amyrins, amyrones and amyryl acetates. The presence of hopanes in some total extracts (up to 12.5%) indicated that the bees also collected petroleum derivatives from vicinal asphalt and used that as an additional ingredient to make propolis. Therefore, caution should be taken when considering the chemical compositions of propolis as potential sources of natural products for biological and pharmacological applications. Moreover, beekeepers should be aware of the proper source of propolis in the flight range of their bee colonies. 相似文献
4.
In order to evaluate hydrocarbon inputs to Crater Lake from anthropogenic and natural sources, samples of water, aerosol,
surface slick and sediment were collected and analyzed by gas chromatography-mass spectrometry (GC-MS) for determination of
their aliphatic and aromatic hydrocarbon concentrations and compositions. Results show that hydrocarbons originate from both
natural (terrestrial plant waxes and algae) and anthropogenic (petroleum use) sources and are entering the lake through direct
input and atmospheric transport. The concentrations of petroleum hydrocarbons range from low to undetectable. The distributions
and abundances of n-alkanes, polycyclic aromatic hydrocarbons (PAH) and unresolved complex mixture (UCM) from petroleum are similar for all surface
slick sampling sites. The estimated levels of PAH in surface slicks range from 7–9 ng/m2 which are low. Transport of petroleum-derived hydrocarbons from the lake surface has resulted in their presence in some sediments,
particularly near the boat operations mooring (total petroleum HC = 1440 μg/kg, dry wt. compared to naturally derived n-alkanes, 240 μg/kg, dry wt.). The presence of biomarkers such as the tricyclic terpanes, hopanes and steranes in shallow
sediments further confirms petroleum input from boat traffic. In the deep lake sediments, petroleum hydrocarbon concentrations
were very low (16 μg/kg, dry wt.). Very low concentrations of PAH were detected in shallow sediments (17–40 μg/kg at 5 m depth
near the boat operations) and deep sediments (3–15 μg/kg at 580 m depth). The individual PAH concentrations in sediments (μg/kg
or ppb range) are at least three orders of magnitude less than reported threshold effects levels (mg/kg or ppm range, test
amphipod Hyalella azteca). Therefore, no adverse effects are expected to occur in benthic biota exposed to these sediments. Boating activities are leaving a detectable level of petroleum in surface waters and lake sediments but these concentrations are very low. 相似文献
5.
Rushdi Ahmed I. Simoneit Bernd R. T. 《Origins of life and evolution of the biosphere》2001,31(1-2):103-118
The formation of lipid compounds during anaqueous Fischer-Tropsch-type reaction was studied withsolutions of oxalic acid as the carbon and hydrogensource. The reactions were conducted in stainlesssteel vessels by heating the oxalic acid solution atdiscrete temperatures from 100 to 400 °C, atintervals of 50 °C for two days each. Themaximum lipid yield, especially for oxygenatedcompounds, is in the window of 150–250 °C. At atemperature of 100 °C only a trace amount oflipids was detected. At temperatures above150 °C the lipid components ranged from C12to >C33 and included n-alkanols, n-alkanoic acids, n-alkyl formates, n-alkanals, n-alkanones, n-alkanes, andn-alkenes, all with essentially no carbon numberpreference. The n-alkanes increased inconcentration over the oxygenated compounds attemperatures of 200 °C and above, with a slightreduction in their carbon number ranges due tocracking. It was also noted that the n-alkanoicacids increased while n-alkanols decreased withincreasing temperature above 200 °C. Attemperatures above 300 °C synthesis competeswith cracking and reforming reactions. At 400 °Csignificant cracking was observed and polynucleararomatic hydrocarbons and their alkylated homologswere detected. The results of this work suggest thatthe formation of lipid compounds by aqueous FTTreactions proceeds by insertion of a CO group at theterminal end of a carboxylic acid functionality toform n-oxoalkanoic acids, followed by reductionto n-alkanoic acids, to n-alkanals, thento n-alkanols. The n-alkenes areintermediate homologs for n-alkan-2-ones andn-alkanes. This proposed mechanism for aqueousFTT synthesis differs from the surface-catalyzedstepwise FT process (i.e., gaseous) of polymerization of methylene reported in the literature. 相似文献
6.
Angelika Otto Bernd R. T. Simoneit Volker Wilde Lutz Kunzmann Wilhelm Püttmann 《Review of Palaeobotany and Palynology》2002,120(3-4):203-215
The terpenoid composition of three fossil resins from macrofossils of Cretaceous and Tertiary conifers has been analyzed by gas chromatography–mass spectrometry (GC–MS). The mono-, sesqui- and diterpenoids which have been identified in the resin extracts are derived from precursors produced by the respective source plants and may be used as chemosystematic markers when compared with terpenoids in extant conifers. Sesquiterpenoids (cedrene, cuparene, cadinanes) and phenolic diterpenoids (ferruginol and derivatives) are the major components in Cupressospermum saxonicum Mai (Miocene). The terpenoid characteristics strongly support a relationship to the Cupressaceae s. str. The resin of Doliostrobus taxiformis (Sternberg) Kva
ek (Eocene) consists of abietane and pimarane type resin acids accompanied by minor amounts of phenolic diterpenoids (ferruginol, hinokiol). According to morphological and anatomical characteristics, D. taxiformis was previously compared to both, extant Araucariaceae and Cupressaceae s.l., but the terpenoid pattern of the resin now supports a relationship to the Cupressaceae s.l. rather than to Araucariaceae. Degraded diterpenoids of the abietane type are the major compounds in the extract of Tritaenia linkii (Roemer) Mägdefrau et Rudolf (Lower Cretaceous) indicating considerable oxidative alteration of the resin. Since the terpenoids in the resin of T. linkii are highly degraded or belong to the common abietane class, the leaves cannot be assigned or compared to any modern family based on their terpenoid composition. The presence of ferruginol probably excludes pinaceous affinities. Terpenoids proved to be valuable chemosystematic markers for fossil conifers once they are adequately preserved. The analysis of resin extracts by GC–MS is a suitable tool for the investigation of soluble compounds in fossil plants. 相似文献
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8.
P. T. Holland B. R. Simoneit P. C. Wszolek A. L. Burlingame 《Origins of life and evolution of the biosphere》1972,3(4):551-561
The gases released on DF dissolution of a variety of samples have been studied by gas chromatography and high resolution mass spectrometry. Results on Apollo 12 samples confirm previous observations that CH4 and C2H6 are released as well as CD4, C2D4, C2D6 and higher deuterated hydrocarbons. The yields correlate with the total carbon content of the samples and the CH4 and C2H6 released may be regarded as indigenous while the deuterated products result from hydrolysis of carbide material. Dissolutions were also performed on five size fractions of sample 14240,5, ranging from >420 to <37 . The yields of CH4, CD4,20Ne and36Ar correlate with the surface area and therefore probably arise from solar wind implantation. Other deuterocarbons released include C2D4, C2D6, C3D6, C3D8 and C4D10. Preliminary pyrolysis results of these size differentiated samples confirmed the presence and surface correlation of the CH4,20Ne and36Ar. Dissolution of the 14148, 14156 and 14149 trench samples showed that their carbon chemistry and solar wind exposure are very similar to that of the 14240 SESC and Apollo 11 and 12 fines of high carbon content. Other interesting components released from the soil samples by DF include D2S, DCN and CS2.This paper is an amplified version of the comments made by Dr Holland during the discussions at the meeting on Lunar Analysis: Significance for Exobiology, held at College Park, Maryland, October 26–28, 1971. 相似文献
9.
Pereira AS Siqueira DS Elias VO Simoneit BR Cabral JA Aquino Neto FR 《Phytochemistry》2002,61(6):711-719
Electron impact mass spectra were measured by high temperature high resolution gas chromatography-mass spectrometry (HT-HRGC-MS) for three homologous series of high molecular weight compounds present in the Amazonian plants Marupá (Simaruba amara) and Brazil nut (Bertholettia excelsa). Based on their mass spectra, the compounds were identified as three wax ester series of alpha-tocopherol (vitamin E), beta-tocopherol and phytol (2,6,10,14-tetramethylhexadec-14-en-16-ol). The interpretations are supported by high resolution mass spectrometry and GC retention indices of authentic standards. 相似文献
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