On the Use of Hydroxyl Radical Kinetics to Assess the Number-Average Molecular Weight of Dissolved Organic Matter

2014 ◽  
Vol 48 (20) ◽  
pp. 11794-11802 ◽  
Author(s):  
Elena Appiani ◽  
Sarah E. Page ◽  
Kristopher McNeill
Keyword(s):  
Molecular Weight ◽  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Hydroxyl Radical ◽  
Average Molecular Weight ◽  
Number Average Molecular Weight

SOME CHARACTERISTICS OF THE ORGANIC MATTER EXTRACTED BY DILUTE INORGANIC ACIDS FROM A PODZOLIC B HORIZON

1958 ◽  
Vol 38 (1) ◽  
pp. 14-22 ◽  
Author(s):  
J. R. Wright ◽  
M. Schnitzer ◽  
R. Levick
Keyword(s):  
Molecular Weight ◽  
Organic Matter ◽  
Average Molecular Weight ◽  
Paper Electrophoresis ◽  
Distilled Water ◽  
Number Average Molecular Weight ◽  
Inorganic Acids ◽  
Halogen Content ◽  
Ph Range ◽  
Almost All

Organic matter was extracted from the B21horizon of a podzol soil by both 0.5 per cent HF and 0.5 per cent HCl. Dialysis of the extracts against distilled water reduced the halogen content to less than 0.1 per cent and the iron plus aluminium to between two and three millimoles per gram of organic matter. Further treatment of this water-dialysed material with EDTA and 8-hydroxyquinoline removed almost all of the iron and about two-thirds of the aluminium.The number average molecular weight of the organic matter, as determined by osmometry, ranged between 47,000 and 53,800. Paper electrophoresis studies showed that this organic matter consisted chiefly of one component, negatively charged, dark-brown in colour and mobile over the pH range investigated (1.8 – 9.0). Only traces to small amounts of glucose, galactose, arabinose and xylose were detected by paper chromatography in both the HF and HCl extracts even after hydrolysis. In addition traces of rhamnose were found in the hydrolyzed HF extract.

Transformation of dissolved organic matter by oxidative polymerization with horseradish peroxidase

2010 ◽  
Vol 62 (2) ◽  
pp. 340-346 ◽  
Author(s):  
S. H. Jee ◽  
Y. J. Kim ◽  
S. O. Ko
Keyword(s):  
Hydrogen Peroxide ◽  
Molecular Weight ◽  
Organic Matter ◽  
Horseradish Peroxidase ◽  
Dissolved Organic Matter ◽  
Structural Characteristics ◽  
Oxidative Polymerization ◽  
Average Molecular Weight ◽  
Size Exclusion ◽  
Potential Hazard

Dissolved organic matter (DOM) has significant influence on the transport and fate of contaminants in multiple phases and it has potential hazard by acting as a precursor of disinfection by-products in water supply. The changes in DOM characteristics, especially by oxidative polymerization might result in different behaviour in the interaction with many contaminants. The aim of this work was to verify the catalytic effects of peroxidase on oxidative polymerization of humic and fulvic substances by examination of the structural characteristics. Transformation of humic acid (HA) and fulvic acid (FA) by oxidative polymerization catalyzed by horseradish peroxidase and hydrogen peroxide were investigated. Size exclusion chromatography, excitation–emission matrices spectra (EEMs), synchronous fluorescence spectra, and infrared spectroscopy was used to evaluate the structural transformation of HA and FA. Molecular weight of HA and FA was continuously changed and their weight-average molecular weight (MWw) reached maximum after 8 h. The MWw of HA and FA were proportionally increased with a dosage of horseradish peroxidase and hydrogen peroxide, indicating that HA and FA was transformed into larger and complex molecules. Spectroscopic results indicated that HA and FA structure contains strong polycyclic aromatic structures with more aromatic rings and a higher degree of conjugation.

Chemistry and Properties of Imide Oligomers from Phenylethynyl-Containing Diamines

2000 ◽  
Vol 12 (1) ◽  
pp. 213-223 ◽  
Author(s):  
J G Smith ◽  
J W Connell
Keyword(s):  
Thin Films ◽  
Molecular Weight ◽  
Research Effort ◽  
Average Molecular Weight ◽  
Number Average Molecular Weight ◽  
Similar Composition ◽  
Imide Oligomers ◽  
Calculated Number

As an extension of work on pendent phenylethynyl-containing imide oligomers, three new diamines containing pendent phenylethynyl groups were prepared and characterized. These diamines were used to prepare pendent and pendent and terminal phenylethynyl imide oligomers via the amide acid route in N-methyl-2-pyrrolidinone at a calculated number average molecular weight of 5000 g mol−1. The pendent phenylethynyl groups were randomly distributed along the oligomer backbone and provided a means of controlling the distance between reactive sites. The imide oligomers were characterized and thermally cured, and the cured polymers evaluated as thin films and compared with materials of similar composition prepared from 3,5-diamino-4′-phenylethynylbenzophenone. This work was performed as part of a continuing research effort to develop structural resins for potential aeronautical applications.

Alternating poly(ester amide)s from glutaric anhydride and α,ω-aminoalcohols: synthesis and thermal properties

e-Polymers ◽  
2003 ◽  
Vol 3 (1) ◽  
Author(s):  
Thomas Fey ◽  
Helmut Keul ◽  
Hartwig Höcker
Keyword(s):  
Molecular Weight ◽  
Thermal Properties ◽  
Homologous Series ◽  
Average Molecular Weight ◽  
Number Average Molecular Weight ◽  
Melting Points ◽  
Glutaric Anhydride ◽  
H Nmr ◽  
Activating Agent ◽  
Dimethylformamide Solution

Abstract Alternating poly(ester amide)s 6a - e were prepared by polycondensation of α-carboxyl-ω-hydroxyamides 3a - e which were obtained by aminolysis of glutaric anhydride (1) and α,ω-aminoalcohols, H2N-(CH2)x-OH (x = 2 - 6) 2a - e. The polycondensation was performed in dimethylformamide solution using a carbodiimide as activating agent, or in bulk with Bu2Sn(OMe)2, Ti(OBu)4 and Sn(octoate)2 as a catalyst. For the polycondensation in bulk, the influence of catalyst and of temperature on the number-average molecular weight was studied. 1H NMR analyses of the poly(ester amide)s clearly show the alternating microstructure. The poly(ester amide)s from glutaric anhydride and the homologous series of α,ω-aminoalcohols are semicrystalline materials; their melting points show the odd/even effect observed for other poly(ester amide)s.

Photoformation of Low-Molecular-Weight Organic Acids from Brown Water Dissolved Organic Matter

2003 ◽  
Vol 37 (18) ◽  
pp. 4190-4198 ◽  
Author(s):  
Thomas Brinkmann ◽  
Philip Hörsch ◽  
Daniel Sartorius ◽  
Fritz H. Frimmel
Keyword(s):  
Molecular Weight ◽  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Organic Acids ◽  
Low Molecular Weight
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