ALIPHATIC CARBOXYLIC ACIDS IN CHERNOZEMIC SOILS

1982 ◽  
Vol 62 (3) ◽  
pp. 487-494 ◽  
Author(s):  
J. F. Dormaar
Keyword(s):  
Organic Matter ◽  
Carboxylic Acid ◽  
Carboxylic Acids ◽  
Dioctyl Phthalate ◽  
Gas Chromatography Mass Spectrometry ◽  
Grass Species ◽  
Aliphatic Carboxylic Acid ◽  
High Resolution Gas Chromatography ◽  
Aliphatic Carboxylic Acids ◽  
Extractable Organic Matter

For Chernozemic soils, published information on the aliphatic carboxylic acid fraction of the organic matter is scarce. Yet, geologically they are chemically stable and persist for long periods of time. The distribution of chloroform/methanol-extractable aliphatic carboxylic acids in five uncultivated and three cultivated Chernozemic soils and the roots of four grass species was, therefore, determined. Twenty-three organic acids (up to C30) were tentatively identified by high resolution gas chromatography-mass spectrometry. Hexanedioic acid and dioctyl phthalate were suspected of being contaminants. The relative proportions of aliphatic carboxylic acids varied for different soils. Tree invasions, overgrazing, and cultivation decreased the total aliphatic carboxylic acid content at the expense of the lower weight aliphatic carboxylic acids. Since the aliphatic carboxylic acids formed only a small portion of the total solvent-extractable organic matter and decreased after cultivation, the results do not explain the observation reported earlier that solvent-extractable organic matter of Chernozemic soils increased as a result of cultivation.

scholarly journals Comparison of Three Solid Phase Materials for the Extraction of Carboxylic Acids from River Water Followed by 2D GC × GC-TOFMS Determination

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
G. O. Bosire ◽  
J. C. Ngila ◽  
H. Parshotam
Keyword(s):  
Carboxylic Acid ◽  
Carboxylic Acids ◽  
Natural Organic Matter ◽  
Solid Phase ◽  
Cooling Water ◽  
Raw Water ◽  
Aliphatic Carboxylic Acid ◽  
Hydrophobic Nature ◽  
Relationship Of

The extraction and determination of aliphatic and aromatic carboxylic acids as well as their influence on the aromaticity and molecularity relationship of natural organic matter (NOM) in water are reported in this study. Three solid phase extraction (SPE) sorbents were used and their extraction efficiencies evaluated after chromatographic determinations (using gas chromatography with a time of flight mass spectrometer (GC × GC-TOFMS) and liquid chromatography with organic carbon detector (LC-OCD)). More than 42 carboxylic acids were identified in raw water from the Vaal River, which feeds the Lethabo Power Generation Station, South Africa, with cooling water. The aromatic carboxylic acid efficiency (28%) was achieved by using Strata™X SPE while the highest aliphatic carboxylic acid efficiency (92.08%) was achieved by silica SPE. The hydrophobic nature of NOM in water depends on the nature of organic compounds in water, whether aromatic or aliphatic. The LC-OCD was used to assess the hydrophobicity levels of NOM as a function of these carboxylic acids in cooling water. The LC-OCD results showed that the aromatic nature of NOM in SPE filtered water followed the order Silica>Strata X>C-18. From the results, the hydrophobicity degree of the samples depended on the type and number of carboxylic acids that were removed by the SPE cartridges.

Direct C(sp3)–H Activation of Carboxylic Acids

Synthesis ◽  
2019 ◽  
Vol 52 (04) ◽  
pp. 479-488 ◽  
Author(s):  
Alexander Uttry ◽  
Manuel van Gemmeren
Keyword(s):  
Carboxylic Acid ◽  
General Solution ◽  
Carboxylic Acids ◽  
Bond Activation ◽  
Acid Moiety ◽  
Group Approach ◽  
Research Fields ◽  
Directing Group ◽  
Aliphatic Carboxylic Acids

Carboxylic acids are important in a variety of research fields and applications. As a result, substantial efforts have been directed towards the C–H functionalization of such compounds. While the use of the carboxylic acid moiety as a native directing group for C(sp2)–H functionalization reactions is well established, as yet there is no general solution for the C(sp3)–H activation of aliphatic carboxylic acids and most endeavors have instead relied on the introduction of stronger directing groups. Recently however, novel ligands, tools, and strategies have emerged, which enable the use of free aliphatic carboxylic acids in C–H-activation-based transformations.1 Introduction2 Challenges in the C(sp3)–H Bond Activation of Carboxylic Acids3 The Lactonization of Aliphatic Carboxylic Acids4 The Directing Group Approach5 The Direct C–H Arylation of Aliphatic Carboxylic Acids6 The Direct C–H Olefination of Aliphatic Carboxylic Acids7 The Direct C–H Acetoxylation of Aliphatic Carboxylic Acids8 Summary

Aliphatic carboxylic acids in buried Ah horizons in Alberta, Canada as paleoenvironmental indicators

1983 ◽  
Vol 20 (5) ◽  
pp. 859-866 ◽  
Author(s):  
J. F. Dormaar
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Carboxylic Acids ◽  
Soil Formation ◽  
Aliphatic Acids ◽  
Southern Alberta ◽  
Aliphatic Carboxylic Acids ◽  
Paleoenvironmental Indicators

In southern Alberta, a buried Ah horizon is frequently present beneath Mazama tephra (ca. 6600 years BP). Drainage conditions during the formation of such buried Ah horizons may determine the quality of the aliphatic carboxylic acids in the soil organic matter. The spectrum of aliphatic acids extracted from a number of buried Ah horizons indeed suggests either well drained or poorly drained conditions during soil formation regardless of the mode of deposition of materials before or after the soil-forming interval. The climate required for development of the well drained paleosols was inferred to be similar to the climate under which surficial Black Chernozemic Ah horizons were formed.

scholarly journals Electrochemical analysis of the carboxy-14C-labelled aliphatic carboxylic acid metabolites resulting from tracer studies

1977 ◽  
Vol 167 (2) ◽  
pp. 505-507 ◽  
Author(s):  
G H Walker ◽  
D E Hathway
Keyword(s):  
Carboxylic Acid ◽  
Electrochemical Analysis ◽  
Acid Biosynthesis ◽  
Tracer Studies ◽  
Aliphatic Carboxylic Acid ◽  
Carboxylic Acid Groups ◽  
Acid Metabolites ◽  
Kolbe Reaction ◽  
Aliphatic Carboxylic Acids ◽  
Important Evidence

14C02 output from carboxy-14C-labelled aliphatic carboxylic acids is measured in the micro-scale Kolbe reaction. Irrespective of whether rats were dosed with 1,1-dichloro[1-14C]ethylene or with chloro[1-14C]acetic acid, 1 mol.equiv. of the resulting thio[14C]diglycollic acid yields by electrolysis approx. 0.7 equiv. of 14CO2, which is interpreted in terms of the labelling of one of the carboxylic acid groups of thiodiglycollic acid. This observation provides important evidence concerning thiodiglycollic acid biosynthesis from 1.1-dichloroethylene.

scholarly journals Microbially mediated reduction of FeIII and AsV in Cambodian sediments amended with 13C-labelled hexadecane and kerogen

2014 ◽  
Vol 11 (5) ◽  
pp. 538 ◽  
Author(s):  
Athanasios Rizoulis ◽  
Wafa M. Al Lawati ◽  
Richard D. Pancost ◽  
David A. Polya ◽  
Bart E. van Dongen ◽  
...  
Keyword(s):  
Organic Matter ◽  
Critical Role ◽  
Stable Isotope Probing ◽  
Mass Spectrometry Analysis ◽  
Gas Chromatography Mass Spectrometry ◽  
Organic Substrates ◽  
Spectrometry Analysis ◽  
Subsurface Sediments ◽  
Extractable Organic Matter ◽  
Long Chain

Environmental context The use of groundwater with elevated concentrations of arsenic for drinking, cooking or irrigation has resulted in the worst mass poisoning in human history. This study shows that organic compounds that can be found in arsenic rich subsurface sediments may be used by indigenous microorganisms, contributing to the release of arsenic from the sediments into the groundwater. This study increases our understanding of the range of organic substrates (and their sources) that can potentially stimulate arsenic mobilisation into groundwaters. Abstract Microbial activity is generally accepted to play a critical role, with the aid of suitable organic carbon substrates, in the mobilisation of arsenic from sediments into shallow reducing groundwaters. The nature of the organic matter in natural aquifers driving the reduction of AsV to AsIII is of particular importance but is poorly understood. In this study, sediments from an arsenic rich aquifer in Cambodia were amended with two 13C-labelled organic substrates. 13C-hexadecane was used as a model for potentially bioavailable long chain n-alkanes and a 13C-kerogen analogue as a proxy for non-extractable organic matter. During anaerobic incubation for 8 weeks, significant FeIII reduction and AsIII mobilisation were observed in the biotic microcosms only, suggesting that these processes were microbially driven. Microcosms amended with 13C-hexadecane exhibited a similar extent of FeIII reduction to the non-amended microcosms, but marginally higher AsIII release. Moreover, gas chromatography–mass spectrometry analysis showed that 65% of the added 13C-hexadecane was degraded during the 8-week incubation. The degradation of 13C-hexadecane was microbially driven, as confirmed by DNA stable isotope probing (DNA-SIP). Amendment with 13C-kerogen did not enhance FeIII reduction or AsIII mobilisation, and microbial degradation of kerogen could not be confirmed conclusively by DNA-SIP fractionation or 13C incorporation in the phospholipid fatty acids. These data are, therefore, consistent with the utilisation of long chain n-alkanes (but not kerogen) as electron donors for anaerobic processes, potentially including FeIII and AsV reduction in the subsurface.

scholarly journals Macromolecular composition of terrestrial and marine organic matter in sediments across the East Siberian Arctic Shelf

2016 ◽  
Vol 10 (5) ◽  
pp. 2485-2500 ◽  
Author(s):  
Robert B. Sparkes ◽  
Ayça Doğrul Selver ◽  
Örjan Gustafsson ◽  
Igor P. Semiletov ◽  
Negar Haghipour ◽  
...  
Keyword(s):  
Organic Matter ◽  
Coastal Erosion ◽  
Principal Component ◽  
Arctic Shelf ◽  
The Arctic ◽  
Gas Chromatography Mass Spectrometry ◽  
Terrestrial Organic Matter ◽  
Pyrolysis Gas ◽  
Siberian Arctic ◽  
Extractable Organic Matter

Abstract. Mobilisation of terrestrial organic carbon (terrOC) from permafrost environments in eastern Siberia has the potential to deliver significant amounts of carbon to the Arctic Ocean, via both fluvial and coastal erosion. Eroded terrOC can be degraded during offshore transport or deposited across the wide East Siberian Arctic Shelf (ESAS). Most studies of terrOC on the ESAS have concentrated on solvent-extractable organic matter, but this represents only a small proportion of the total terrOC load. In this study we have used pyrolysis–gas chromatography–mass spectrometry (py-GCMS) to study all major groups of macromolecular components of the terrOC; this is the first time that this technique has been applied to the ESAS. This has shown that there is a strong offshore trend from terrestrial phenols, aromatics and cyclopentenones to marine pyridines. There is good agreement between proportion phenols measured using py-GCMS and independent quantification of lignin phenol concentrations (r2 = 0.67, p < 0.01, n = 24). Furfurals, thought to represent carbohydrates, show no offshore trend and are likely found in both marine and terrestrial organic matter. We have also collected new radiocarbon data for bulk OC (14COC) which, when coupled with previous measurements, allows us to produce the most comprehensive 14COC map of the ESAS to date. Combining the 14COC and py-GCMS data suggests that the aromatics group of compounds is likely sourced from old, aged terrOC, in contrast to the phenols group, which is likely sourced from modern woody material. We propose that an index of the relative proportions of phenols and pyridines can be used as a novel terrestrial vs. marine proxy measurement for macromolecular organic matter. Principal component analysis found that various terrestrial vs. marine proxies show different patterns across the ESAS, and it shows that multiple river–ocean transects of surface sediments transition from river-dominated to coastal-erosion-dominated to marine-dominated signatures.

Aliphatic Sulfonyl Fluoride Synthesis via Reductive Decarboxylative Fluorosulfonylation of Aliphatic Carboxylic Acids NHPI Esters

2022 ◽  
Author(s):  
Zhanhu Ma ◽  
Yongan Liu ◽  
Xiaoyu Ma ◽  
Xiaojun Hu ◽  
Yong Guo ◽  
...  
Keyword(s):  
Carboxylic Acid ◽  
Sulfur Dioxide ◽  
Carboxylic Acids ◽  
Efficient Method ◽  
Aliphatic Carboxylic Acids ◽  
Sulfonyl Fluoride

Based on radical sulfur dioxide insertion and fluorination strategy, we have developed an efficient method for aliphatic sulfonyl fluoride synthesis from abundant carboxylic acid, reductant, sulfur dioxide surrogate and electrophilic...

Natural and anthropogenic sources of extractable organic matter in sediments from the coastal zone of the Arabian Gulf in Saudi Arabia

2021 ◽  
Author(s):  
Ahmed I. Rushdi ◽  
Aarif H. El-Mubarak ◽  
Bernd R. T. Simoneit ◽  
Miguel A. Goni ◽  
Mohammed A. Qurban ◽  
...  
Keyword(s):  
Saudi Arabia ◽  
Organic Matter ◽  
Higher Plants ◽  
Gulf Coast ◽  
Arabian Gulf ◽  
Complex Mixture ◽  
Anthropogenic Sources ◽  
Gas Chromatography Mass Spectrometry ◽  
Terrestrial Vegetation ◽  
Extractable Organic Matter

Abstract Surface sediment samples from the Arabian Gulf coast of Saudi Arabia were collected by Van Veen grab sampler to identify the characteristics, distribution, levels, and to discriminate between natural and anthropogenic sources of the total extractable organic matter (TEOM). The dried and sieved sediments were extracted with a dichloromethane/methanol mixture for analysis by gas chromatography-mass spectrometry. The TEOM included n-alkanes (353.9±283.8 ng.g−1), n-alkanols (283.2±296.1 ng.g−1), fatty acid methyl esters (245.2±353.7 ng.g−1), hopanes (100.7±158.2 ng.g−1), steranes (58.5±96.3 ng.g−1), triterpenoids (18.9±21.1 ng.g−1), steroids (15.3±17.0 ng.g−1), polycyclic aromatic hydrocarbons (PAHs) (0.48±1.19 ng.g−1), as well as an unresolved complex mixture (UCM =1633±3151 ng.g−1) and petrochemicals (343.1±424.2 ng.g−1). The major sources of these TEOM compound groups were anthropogenic (petroleum and petrochemical) and natural (lipids from higher plants, marine material, and microbiota) inputs. Anthropogenic contaminants from petroleum products ranged from 46.6-85.6% of the TEOM, whereas petrochemicals varied from 10.7-40.6%. Biogenic influx from terrestrial vegetation ranged from 5.7-19.3%, and marine biotic sources varied from 11.1-37.5%. The continuous accumulation of anthropogenic contaminants will ultimately affect the critical habitats of this marine coastal region. This provides a basis for further studies to understand human and developmental activities on delivery, deposition processes, distribution, and biogeochemical alteration of organic matter in the coastal zones of the Arabian Gulf. Such studies are important for sustainable development and protection of these key regional habitats.

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