scholarly journals Decomposition of Dimethoate and Omethoate in Aqueous Solutions – Half-Life, Neurotoxicity and Mechanism of Hydrolysis

2021 ◽  
Author(s):  
Vladan J. Anićijević ◽  
Milena Petković ◽  
Igor A Pašti ◽  
Tamara Lazarević-Pašti
Keyword(s):  
Aqueous Solutions ◽  
Alkaline Hydrolysis ◽  
Quantum Chemical ◽  
Contaminated Water ◽  
Organophosphate Pesticides ◽  
Chemical Transformations ◽  
Acidic Solutions ◽  
Mechanism Of Hydrolysis ◽  
Hydrolysis Of ◽  
Over Time

Organophosphate pesticides are used in large quantities. However, they exhibit toxic effects on non-target organisms. Dimethoate and its oxo-analog omethoate inhibit acetylcholinesterase and are toxic for mammals. Moreover, they show extreme toxicity for bees. Once in the environment, they undergo chemical transformations and decomposition. We show that dime-thoate and omethoate decompose rapidly in alkaline aqueous solutions (half-lives 5.7 and 0.89 days) but are highly stable in acidic solutions (half-lives 124 and 104 days). These differences are explained using quantum chemical calculations, indicating that a weaker P–S bond in omethoate is more susceptible to hydrolysis, particularly at a high pH. The toxicity of these pesticides solutions decreases over time, indicating that no or very little highly toxic omethoate is formed during hydrolysis. Presented data can be used to predict dimethoate and omethoate concentrations in contaminated water depending on pH. Presented results suggest that alkaline hydrolysis of organophosphates has an advantage over other techniques for their removal since there is no risk of omethoate accumulation and increased toxicity of contaminated water.

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.

Mechanism of Hydrolysis of Ethyl Benzimidates in Acidic Solutions

1965 ◽  
Vol 30 (3) ◽  
pp. 699-702 ◽  
Author(s):  
Robert H. DeWolfe ◽  
Frederick B. Augustine
Keyword(s):  
Acidic Solutions ◽  
Mechanism Of Hydrolysis ◽  
Hydrolysis Of

A Green and Highly Efficient Protocol for Hydrolysis of Substituted Benzyl Chloride Using Ionic Liquid [bmim]BF4 as Phase-Transfer Catalyst

2010 ◽  
Vol 113-116 ◽  
pp. 1990-1992 ◽  
Author(s):  
Yong Zhang ◽  
Hong Jun Zang ◽  
Bo Wen Cheng
Keyword(s):  
Ionic Liquid ◽  
Aqueous Solutions ◽  
Benzyl Alcohol ◽  
Alkaline Hydrolysis ◽  
Benzyl Chloride ◽  
Phase Transfer ◽  
Phase Transfer Catalyst ◽  
Present Procedure ◽  
Hydrolysis Of ◽  
By Products

Alkaline hydrolysis of substituted benzyl chloride (BzCl) in ionic liquid [bmim]BF4 is investigated. The presence of the [bmim]BF4, increased the solubility of substituted BzCl in aqueous solutions and increased the selectivity toward the formation of benzyl alcohol. The main advantages of the present procedure are shorter time, higher yields, benignancy to environment and no by-products.

Hydrolysis of plutonium(IV) in acidic solutions: no effect of hydrolysis on absorption-spectra of mononuclear hydroxide complexes

2007 ◽  
Vol 95 (1) ◽  
Author(s):  
Clemens Walther ◽  
H. R. Cho ◽  
Christian M. Marquardt ◽  
Volker Neck ◽  
A. Seibert ◽  
...  
Keyword(s):  
Optical Absorption ◽  
Aqueous Solutions ◽  
Absorption Spectra ◽  
Absorption Spectroscopy ◽  
Optical Absorption Spectroscopy ◽  
Acidic Solutions ◽  
The Past ◽  
Hydrolysis Of

Tetravalent plutonium readily undergoes hydrolysis even in highly acidic aqueous solutions. In the past, many attempts were made to quantify hydrolysis species by means of optical absorption spectroscopy. In the present work solutions ranging from 10

scholarly journals Acidic and alkaline bimolecular hydrolysis of substituted formanilides. Computational analysis and modelling of substitution effects

2017 ◽  
Vol 10 (1) ◽  
pp. 35-40
Author(s):  
Martin Michalík ◽  
Peter Škorňa ◽  
Vladimír Lukeš ◽  
Erik Klein
Keyword(s):  
Alkaline Hydrolysis ◽  
Rate Constants ◽  
Quantum Chemical ◽  
Computational Analysis ◽  
Hydrolysis Rate ◽  
Substitution Effects ◽  
Chemical Methods ◽  
Quantum Chemical Methods ◽  
Hydrolysis Of

Abstract In this article, the study of 67 compounds representing various para-, meta- and ortho- substituted formanilides is presented. These molecules and the products of their acidic and alkaline hydrolysis were studied using DFT quantum chemical methods in order to calculate the reaction enthalpies. These enthalpies are correlated with the hydrolysis rate constants, kH, published for the acid-catalysed acyl cleavage bimolecular (AAC2) mechanism and the modified base-catalysed acyl cleavage bimolecular (BAC2) mechanism. The found linear dependences can be used for the prediction of rate constants of non-synthesised formanilide derivatives.

Preferential Hydrolysis of Kynurenine Peptides

1969 ◽  
Vol 24 (3) ◽  
pp. 294-300 ◽  
Author(s):  
F. M. Veronese ◽  
E. Boccu ◽  
C. A. Benassi ◽  
E. Scoffone
Keyword(s):  
Alkaline Hydrolysis ◽  
Alkaline Media ◽  
Amino Group ◽  
Acidic Media ◽  
Model Compounds ◽  
Preferential Cleavage ◽  
Controlled Potential Electrolysis ◽  
Mechanism Of Hydrolysis ◽  
Controlled Potential ◽  
Hydrolysis Of

The preferential cleavage of kynurenine peptides bonds was studied through reduction to γ- (o- aminophenyl) -homoserine derivatives followed by mild acidic as well as mild alkaline hydrolysis. The reduction of keto group of kynurenine to hydroxy one was achieved by controlled potential electrolysis at -1.05 Volts. In order to understand the mechanism of hydrolysis some model compounds related to kynurenine peptides were also synthesized and studied. Hydrolysis of γ- (o-aminophenyl)-homoserine peptides in acidic media is related only to the assistance of γ-hydroxy function, whereas in alkaline media also aromatic amino group is involved.

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