INTERACTIONS OF HEXAMETHYLENE TETRAMINE WITH BIOPOLYMERS AND MODEL COMPOUNDS IN AQUEOUS SOLUTION

2009 ◽  
Vol 3 (1-4) ◽  
pp. 49-51 ◽  
Author(s):  
V. Crescenz ◽  
F. Quadrifoglio ◽  
A. Cesaro
Keyword(s):  
Aqueous Solution ◽  
Model Compounds ◽  
Hexamethylene Tetramine

The growth and dissolution of hexamethylene tetramine in aqueous solution

1975 ◽  
Vol 30 (1) ◽  
pp. 77-85 ◽  
Author(s):  
P. Bomio ◽  
J.R. Bourne ◽  
R.J. Davey
Keyword(s):  
Aqueous Solution ◽  
Hexamethylene Tetramine

The Chemical Evolution of a Nitrogenase Model, 20 Alkyl Molybdates(VI) and the Mechanism of Hydrocarbon Production by Nitrogenase [1]

1982 ◽  
Vol 37 (3) ◽  
pp. 380-385 ◽  
Author(s):  
G. N. Schrauzer ◽  
Laura A. Hughes ◽  
Norman Strampach
Keyword(s):  
Aqueous Solution ◽  
Alkaline Hydrolysis ◽  
Room Temperature ◽  
Bond Cleavage ◽  
Model Compounds ◽  
Hydrocarbon Production ◽  
Acidic Solutions ◽  
Reducing Conditions ◽  
Hydrolysis Of ◽  
Derivatives Of

Abstract Colorless alkylmolybdates(VI) of composition R-MoO3-are generated in aqueous solutions by the alkaline hydrolysis of complexes R-Mo(Bpy)(0)2Br(Bpy = 2,2′-bipyridyl, R = CH3 and higher alkyl). At room temperature in alkaline aqueous solution, the new organometallic derivatives of oxomolybdate(VI) are remarkably resistant against Mo-C bond hydrolysis. Decomposition occurs more rapidly on heating, affording unrearranged alkanes according to the eq.: R-MoO3- + OH-→RH + Mo04=. In acidic solutions, the methylmolybdate(VI) species decomposes with the formation of a mixture of methane and ethane while higher alkylmolybdates carrying hydrogen in the β-position relative to molybdenum undergo Mo-C bond heterolysis by way of β-elimina-tion: R-CH2CH2-MoO3 → Mo+4 (aq) + H+ + R-CH = CH2. The Mo-C bond of alkylmolybdates is resistant to oxidants but is very sensitive to cleavage under reducing conditions. Reductive Mo-C bond cleavage occurs particularly rapidly in the presence of thiols and reduced ferredoxin model compounds. The latter reactions simulate the terminal steps of hydrocarbon producing reactions of nitrogenase with alternate substrates such as CN-, R-CN or R-NC, confirming previous mechanistic conclusions concerning the mechanism of nitrogenase action.

Comparative effect of ozone, chlorine dioxide, and hydrogen peroxide on lignin: Reactions affecting pulp colour in the final bleaching stage

Holzforschung ◽  
2007 ◽  
Vol 61 (6) ◽  
pp. 628-633 ◽  
Author(s):  
Guillaume Pipon ◽  
Christine Chirat ◽  
Dominique Lachenal
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Peroxide ◽  
Chlorine Dioxide ◽  
Reaction Mechanisms ◽  
Decomposition Mechanism ◽  
Comparative Effect ◽  
Model Compounds ◽  
Small Chemical

Abstract Several lignin-like model compounds (vanillin, syringaldehyde, guaiacol, syringol, p-benzoquinone, naphthoquinone) and commercial softwood lignin were submitted to small charges of ozone, chlorine dioxide and hydrogen peroxide in aqueous solution under conditions simulating a final bleaching stage. In the case of ozone, the coloured quinone models were directly destroyed, whereas the phenolic models and lignin underwent a two-step decomposition mechanism: chromophores were formed at very low ozone charges, and then were destroyed with increasing ozone charge. Chlorine dioxide had hardly any effects on the quinone models, but formed coloured groups from the phenolic models and lignin. However, these were more intensely coloured and were only partially removed with higher ClO2 charges. As for hydrogen peroxide, the colour of lignin and naphthoquinone were directly removed, at least partially, but high H2O2 charges were necessary. Consequently, ozone seems to be the best reagent for final bleaching in which small chemical charges are applied. We suggest reaction mechanisms between ozone and the phenolic model compounds and p-benzoquinone that can explain the observations.

The reaction mechanism of catalytic oxidation with hydrogen peroxide and ozone in aqueous solution

2003 ◽  
Vol 47 (1) ◽  
pp. 179-184 ◽  
Author(s):  
J.S. Park ◽  
H. Choi ◽  
K.H. Ahn
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Peroxide ◽  
Reaction Mechanism ◽  
Catalytic Oxidation ◽  
Catalytic Ozonation ◽  
Sorption Behavior ◽  
Model Compounds ◽  
Reaction Characteristics ◽  
Hydrophobic Portion ◽  
Bicarbonate Addition

The sorption and catalytic oxidation of model compounds (pCBA and phenanthrene) and NOM on FeOOH were investigated using hydrogen peroxide and ozone, respectively. After oxidation with ozone, the hydrophobic, transphilic, and hydrophilic NOM fractions were isolated using XAD-8 and -4 resins to analyze the reaction characteristics. The sorption of pCBA was strongly dependent upon the pH, but phenanthrene exhibited a sorption behavior that was independent of the pH. In the case of NOM, the hydrophobic portion showed higher sorption affinity than hydrophilic and transphilic at pH 7.2. The concentrations of model compounds and oxidants were measured during the oxidations and the efficiency was compared for tests done with ozone alone and those using catalytic ozonation. Through the comparison of the sorption and decomposition of the model compounds, along with the effects of bicarbonate addition, mechanisms for catalytic oxidation with hydrogen peroxide or ozone were proposed, respectively.

Molecular Recognition of Inositol 1,4,5-Trisphosphate and Model Compounds in Aqueous Solution by Ditopic Zn2+Complexes Containing Chiral Linkers

2010 ◽  
Vol 49 (11) ◽  
pp. 5316-5327 ◽  
Author(s):  
Masanori Kitamura ◽  
Hiroyuki Nishimoto ◽  
Keita Aoki ◽  
Masato Tsukamoto ◽  
Shin Aoki
Keyword(s):  
Aqueous Solution ◽  
Molecular Recognition ◽  
Model Compounds ◽  
Inositol 1,4,5 Trisphosphate

Nitrate Selectivity of Ion-Exchange Resins and of Their Model Compounds. I. Conductance Measurements on Benzyltrialkylammonium Salts

1990 ◽  
Vol 43 (12) ◽  
pp. 1983
Author(s):  
BJ Steel ◽  
AS Kayaalp ◽  
T Kurucsev ◽  
AD Ward ◽  
MB Jackson
Keyword(s):  
Aqueous Solution ◽  
Ion Exchange ◽  
Concentration Dependence ◽  
Ion Pairing ◽  
Association Constants ◽  
Ion Exchange Resins ◽  
Methyl Ethyl ◽  
Model Compounds ◽  
Sulfate Salts ◽  
Exchange Resins

The concentration dependence of the conductance in aqueous solution of a series of benzyltrialkylammonium chlorides, nitrates and sulfates was measured. The n-alkyl substituents in this series were methyl, ethyl, propyl , butyl and pentyl. The conductances of the chlorides, nitrates and sulfates fit satisfactorily the electrostatic ion pairing models relevant to 1 : 1 and 1 : 2 electrolytes. The extent of ion pairing is small in all the solutions studied but consistently larger for nitrates and sulfates compared with chlorides. The dependence of the association constants on the alkyl substitutents shows different trends for the monovalent anions compared with the sulfate salts.

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