Bulk chemical characteristics of soluble polar organic molecules formed through condensation of formaldehyde: Comparison with soluble organic molecules in Murchison meteorite

2019 ◽  
Vol 53 (1) ◽  
pp. 41-51 ◽  
Author(s):  
Yuki Isono ◽  
Shogo Tachibana ◽  
Hiroshi Naraoka ◽  
François-Régis Orthous-Daunay ◽  
Laurette Piani ◽  
...  
Keyword(s):  
Organic Molecules ◽  
Chemical Characteristics ◽  
Murchison Meteorite ◽  
Bulk Chemical

On The Nature of Interstellar Organic Chemistry

1997 ◽  
Vol 161 ◽  
pp. 89-96 ◽  
Author(s):  
Steven B. Charnley
Keyword(s):  
Gas Phase ◽  
Molecular Clouds ◽  
Organic Molecules ◽  
Single Atom ◽  
Addition Reactions ◽  
Mass Star ◽  
Quantum Tunnelling ◽  
Dark Clouds ◽  
Murchison Meteorite ◽  
Low Mass

AbstractA theory for the origin of all organic molecules observed in regions of massive and low-mass star formation, as well as in dark molecular clouds is described. On dust grains, single atom addition reactions and stability of the intermediate radicals, mechanisms similar to those believed to form the organic component of the Murchison meteorite, lead to a very limited number of mantle compositions depending upon the degree of hydrogenation. The key step in the theory is the formation of the formyl radical by H atom addition (by quantum tunnelling) to CO. Subsequent H atom additions lead to formaldehyde and methanol, as previously suggested; C, N, and O atoms can also undergo additions to HCO. For increasing hydrogenation, the mantle types include one in which there is little contribution from formyl-initiated chemistry; one in which an acetylenic chain develops through C atom additions; and others where the acetylenic chain is increasingly hydrogenated to form aldehydes and alcohols. Following evaporation of grain mantles, such as occurs in protostellar «hot cores», these molecules can form new organics, for example, by alkyl cation transfer from alcohols. In dark clouds, different mantles lead to different gas phase organics. This scenario accounts naturally for the formation of many interstellar organics for which none presently exists, predicts observable correlations between specific interstellar molecules, indicates the presence of many new organic molecules and why several others are not observed.

scholarly journals ‘Star Dust Memories’—A Brief History of the Murchison Carbonaceous Chondrite

2003 ◽  
Vol 20 (4) ◽  
pp. vii-ix ◽  
Author(s):  
Dermot A. Henry
Keyword(s):  
Solar System ◽  
Organic Molecules ◽  
Carbonaceous Chondrite ◽  
Origins Of Life ◽  
Scientific Publications ◽  
Murchison Meteorite ◽  
History Of ◽  
The Subject

AbstractThe rare carbonaceous chondrite which fell around the township of Murchison in northern Victoria, Australia, in 1969 has probably been the subject of more scientific publications than any other meteorite. The discovery of grains formed in a presolar environment and the abundance of organic molecules within the Murchison meteorite have facilitated studies of the formation of the Solar System, the development of stars and the origins of life.

scholarly journals Formation of Highly Oxygenated Organic Molecules from α-Pinene Ozonolysis: Chemical Characteristics, Mechanism, and Kinetic Model Development

2019 ◽  
Vol 3 (5) ◽  
pp. 873-883 ◽  
Author(s):  
Ugo Molteni ◽  
Mario Simon ◽  
Martin Heinritzi ◽  
Christopher R. Hoyle ◽  
Anne-Kathrin Bernhammer ◽  
...  
Keyword(s):  
Kinetic Model ◽  
Organic Molecules ◽  
Model Development ◽  
Chemical Characteristics

Bulk Chemical Characteristics of Dissolved Organic Matter in the Ocean

Science ◽  
1992 ◽  
Vol 255 (5051) ◽  
pp. 1561-1564 ◽  
Author(s):  
R. BENNER ◽  
J. D. PAKULSKI ◽  
M. MCCARTHY ◽  
J. I. HEDGES ◽  
P. G. HATCHER
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Chemical Characteristics ◽  
Bulk Chemical

scholarly journals Assessment of Tarmat Contamination and its Chemical Characterization along the West Coast of Qatar, Arabian Gulf

2020 ◽  
Author(s):  
Haseeba Kaiprath Puthiyapurayil ◽  
Veerasingam S ◽  
Shafeeq H ◽  
Jassim Al-Khayat ◽  
Vethamony P
Keyword(s):  
West Coast ◽  
Marine Ecosystem ◽  
High Tide ◽  
Chemical Characterization ◽  
Pollution Level ◽  
Chemical Characteristics ◽  
Northwestern Part ◽  
The West ◽  
Sampling Campaign ◽  
Bulk Chemical

Tarmat/Oil residue (hereafter ‘TM’) is one of the serious threats to the marine ecosystem due to their toxicity, persistence and bioaccumulation problems. To assess the level of TM contamination and to determine the primary differences in the chemical composition, a sampling campaign was conducted in 12 beaches along the west coast of Qatar. TM contamination ranged from 0 to 104 gm-1 with an average value of 9.25 gm-1. Moreover, all the TM samples were found to be highly weathered, blackish and asphalt-like material. Though the current TM pollution level is thirty-fold lesser than those found during 1993 to 1997, the contamination pattern was similar (i.e. northwestern part was highly contaminated). The distribution of TM along the Qatar coast is as follows: Low tide> high tide> berm line. Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) spectroscopy was used to examine the bulk chemical characteristics of the TMs. These bulk chemical characteristics have revealed several features unique to different types of TM samples.

High Resolution Replication of Organoclay Surfaces

1982 ◽  
Vol 40 ◽  
pp. 576-577
Author(s):  
W. W. Barker ◽  
W. E. Rigsby ◽  
V. J. Hurst ◽  
W. J. Humphreys
Keyword(s):  
Clay Mineral ◽  
Organic Molecule ◽  
Organic Molecules ◽  
X Ray Diffraction ◽  
Xrd Pattern ◽  
X Ray ◽  
Naturally Occurring ◽  
Silicate Layers ◽  
Mineral Identification

Experimental clay mineral-organic molecule complexes long have been known and some of them have been extensively studied by X-ray diffraction methods. The organic molecules are adsorbed onto the surfaces of the clay minerals, or intercalated between the silicate layers. Natural organo-clays also are widely recognized but generally have not been well characterized. Widely used techniques for clay mineral identification involve treatment of the sample with H2 O2 or other oxidant to destroy any associated organics. This generally simplifies and intensifies the XRD pattern of the clay residue, but helps little with the characterization of the original organoclay. Adequate techniques for the direct observation of synthetic and naturally occurring organoclays are yet to be developed.

Direct phase determination in electron crystallography: small organic molecules

1992 ◽  
Vol 50 (2) ◽  
pp. 1166-1167
Author(s):  
Douglas L. Dorset
Keyword(s):  
Organic Molecules ◽  
Data Sets ◽  
Temperature Structure ◽  
3D Analysis ◽  
Intensity Data ◽  
Electron Crystallography ◽  
Phase Determination ◽  
Measured Intensity ◽  
3D Data

The quantitative use of electron diffraction intensity data for the determination of crystal structures represents the pioneering achievement in the electron crystallography of organic molecules, an effort largely begun by B. K. Vainshtein and his co-workers. However, despite numerous representative structure analyses yielding results consistent with X-ray determination, this entire effort was viewed with considerable mistrust by many crystallographers. This was no doubt due to the rather high crystallographic R-factors reported for some structures and, more importantly, the failure to convince many skeptics that the measured intensity data were adequate for ab initio structure determinations.We have recently demonstrated the utility of these data sets for structure analyses by direct phase determination based on the probabilistic estimate of three- and four-phase structure invariant sums. Examples include the structure of diketopiperazine using Vainshtein's 3D data, a similar 3D analysis of the room temperature structure of thiourea, and a zonal determination of the urea structure, the latter also based on data collected by the Moscow group.

Sampling and analysis of the air-water interface with SEM and EDS of microlayers

1989 ◽  
Vol 47 ◽  
pp. 1004-1005
Author(s):  
Randall W. Smith ◽  
John Dash
Keyword(s):  
Heavy Metals ◽  
Surface Microlayer ◽  
Surface Films ◽  
Water Interface ◽  
Physical Processes ◽  
Infrared Spectroscopic Analysis ◽  
Eds Analysis ◽  
Air Water Interface ◽  
Significant Area ◽  
Bulk Chemical

The structure of the air-water interface forms a boundary layer that involves biological ,chemical geological and physical processes in its formation. Freshwater and sea surface microlayers form at the air-water interface and include a diverse assemblage of organic matter, detritus, microorganisms, plankton and heavy metals. The sampling of microlayers and the examination of components is presently a significant area of study because of the input of anthropogenic materials and their accumulation at the air-water interface. The neustonic organisms present in this environment may be sensitive to the toxic components of these inputs. Hardy reports that over 20 different methods have been developed for sampling of microlayers, primarily for bulk chemical analysis. We report here the examination of microlayer films for the documentation of structure and composition.Baier and Gucinski reported the use of Langmuir-Blogett films obtained on germanium prisms for infrared spectroscopic analysis (IR-ATR) of components. The sampling of microlayers has been done by collecting fi1ms on glass plates and teflon drums, We found that microlayers could be collected on 11 mm glass cover slips by pulling a Langmuir-Blogett film from a surface microlayer. Comparative collections were made on methylcel1ulose filter pads. The films could be air-dried or preserved in Lugol's Iodine Several slicks or surface films were sampled in September, 1987 in Chesapeake Bay, Maryland and in August, 1988 in Sequim Bay, Washington, For glass coverslips the films were air-dried, mounted on SEM pegs, ringed with colloidal silver, and sputter coated with Au-Pd, The Langmuir-Blogett film technique maintained the structure of the microlayer intact for examination, SEM observation and EDS analysis were then used to determine organisms and relative concentrations of heavy metals, using a Link AN 10000 EDS system with an ISI SS40 SEM unit. Typical heavy microlayer films are shown in Figure 3.

Applications of SEM/EDXA in cement clinker investigation

1990 ◽  
Vol 48 (4) ◽  
pp. 870-871
Author(s):  
Arezki Tagnit-Hamou ◽  
Shondeep L. Sarkar
Keyword(s):  
Mineralogical Composition ◽  
Physicochemical Characteristics ◽  
Cement Clinker ◽  
Accurate Information ◽  
Phase Identification ◽  
History Of ◽  
Bulk Chemical ◽  
Resolution Imaging ◽  
Proven Method ◽  
Instantaneous Chemical

All the desired properties of cement primarily depend on the physicochemical characteristics of clinker from which the cement is produced. The mineralogical composition of the clinker forms the most important parameter influencing these properties.Optical microscopy provides reasonably accurate information pertaining to the thermal history of the clinker, while XRDA still remains the proven method of phase identification, and bulk chemical composition of the clinker can be readily obtained from XRFA. Nevertheless, all these microanalytical techniques are somewhat limited in their applications, and SEM/EDXA combination fills this gap uniquely by virtue of its high resolution imaging capability and possibility of instantaneous chemical analysis of individual phases.Inhomogeneities and impurities in the raw meal, influence of kiln conditions such as sintering and cooling rate being directly related to the microstructure can be effectively determined by SEM/EDXA. In addition, several physical characteristics of cement, such as rhcology, grindability and hydraulicity also depend on the clinker microstructure.

Characterization of defects in tabular silver halide grains

1990 ◽  
Vol 48 (4) ◽  
pp. 1046-1047
Author(s):  
C. Goessens ◽  
D. Schryvers ◽  
J. Van Landuyt ◽  
A. Verbeeck ◽  
R. De Keyzer
Keyword(s):  
Radiation Damage ◽  
Silver Halide ◽  
Chemical Characteristics ◽  
X Ray ◽  
Free Region ◽  
Central Defect ◽  
Crystallographic Defects ◽  
Physical And Chemical ◽  
Two Sides

Silver halide grains (AgX, X=Cl,Br,I) are commonly recognized as important entities in photographic applications. Depending on the preparation specifications one can grow cubic, octahedral, tabular a.o. morphologies, each with its own physical and chemical characteristics. In the present study crystallographic defects introduced by the mixing of 5-20% iodide in a growing AgBr tabular grain are investigated. X-ray diffractometry reveals the existence of a homogeneous Ag(Br1-xIx) region, expected to be formed around the AgBr kernel. In fig. 1 a two-beam BF image, taken at T≈100 K to diminish radiation damage, of a triangular tabular grain is presented, clearly showing defect contrast fringes along four of the six directions; the remaining two sides show similar contrast under relevant diffraction conditions. The width of the central defect free region corresponds with the pure AgBr kernel grown before the mixing with I. The thickness of a given grain lies between 0.15 and 0.3 μm: as indicated in fig. 2 triangular (resp. hexagonal) grains exhibit an uneven (resp. even) number of twin interfaces (i.e., between + and - twin variants) parallel with the (111) surfaces. The thickness of the grains and the existence of the twin variants was confirmed from CTEM images of perpendicular cuts.

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