Degrading Pesticides with Waste Product: Imidazole-Functionalized Rice Husk Catalyst for Organophosphate Detoxification

Ferreira, Janaina G.; Orth, Elisa S.

doi:10.21577/0103-5053.20170027

Cited by 5 publications

(4 citation statements)

References 23 publications

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“…The p K a of the imidazolium moiety is close to 7.0, allowing it to act as a general acid, a general base, or a nucleophile in aqueous solutions of neutral pH. Therefore, it is not surprising that many artificial catalytic systems which contain the imidazole moiety have been developed aiming to mimic the natural role of this important heterocycle. − To probe the performance of our novel particles, we evaluated the degradation of a model organophosphate diethyl 2,4-dinitrophenyl phosphate (DEDNPP), known to be decomposed by imidazole, , in the presence of 4NPM-MNP modified with 1-(3-aminopropyl)imidazole (API-MNP) (Scheme ). Figure A,B shows representative kinetics for decomposition of a 0.5 mM DEDNPP solution at pH 5.4 and 7.4, respectively [kinetics at other pHs are given in the Supporting Information (Figure S10)].…”

Section: Resultsmentioning

confidence: 99%

From the Shelf to the Particle: Preparation of Highly Organic-Functionalized Magnetic Composites via 4-Nitrophenyl Reactive Ester

et al. 2019

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Preparation of chemically tunable magnetic nanoparticles (MNPs) is of great interest in many technological fields. Although numerous methods have been developed to prepare MNPs coated with functional organic moieties, most of them are complex, multistep, and involve the preparation of a specific ligand to be inserted on the particle surface. Herein, we describe the preparation of MNPs covered with reactive polymer poly(4-nitrophenyl methacrylate). The composite was prepared by the dispersion polymerization of 4-nitrophenyl methacrylate in the presence of magnetite nanoparticles stabilized by oleic acid. The novel material can be easily modified with amines to give chemically stable amide bonds without installation of pH-dependent features in the link. The extent of particle modification is readily monitored by the release of 4-nitrophenol from the polymer using UV–vis spectrophotometry. Good agreement between the degree of functionalization assessed by colorimetry and elemental analysis was obtained, and functionalization up to 3 mmol g–1 is easily attained. To illustrate the applicability of the method for catalyst development, we prepared imidazole-covered MNPs that accelerate the hydrolysis of a model organophosphate, with rate constants approximately 105-fold higher than the spontaneous hydrolysis. The catalyst can be recovered by a magnet and recycled without appreciable loss of catalytic activity.

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Section: Resultsmentioning

confidence: 99%

From the Shelf to the Particle: Preparation of Highly Organic-Functionalized Magnetic Composites via 4-Nitrophenyl Reactive Ester

et al. 2019

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“…For the less reactive P=S family, N‐alkylation of IMZ is more favorable, which also leads to nontoxic diesters in a noncatalytic but effective process . The high efficiency and versatility of IMZ has also inspired many IMZ‐based catalysts for OP detoxification, including polymers, nanomaterials, and even waste products, reaffirming the importance of searching for new reactive scaffolds.…”

Section: Introductionmentioning

confidence: 99%

Competitive Reactivity of Tautomers in the Degradation of Organophosphates by Imidazole Derivatives

Campos

Silva

Menezes

et al. 2020

Chemistry A European J

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The harmful impact caused by pesticides on human health and the environment necessitates the developmento fe fficient degradation processes and control of prohibited stocks of such substances. Organophosphates (OPs) are among the most used agrochemicals in the world and their degradation can proceed through several possible pathways. Investigatingt he reactivity of OPs with nucleophilic speciesa llows one to propose new and efficientc atalyst scaffolds for use in detoxification. In light of the remarkable catalytic activity of imidazole (IMZ) at promoting dephosphorylation processes of OPs, the reactivity of 4(5)-hy-droxymethylimidazole( HMZ) with diethyl-2,4-dinitrophenylphosphate (DEDNPP) and Paraoxon are evaluatedb y combining experimental andtheoretical approaches.I tisobservedt hat HMZ is an efficient and regiospecific catalyst with reactivity modulated by competing tautomers. To propose an optimal IMZ-based catalyst, quantumc hemical calculations were performed for monosubstituted 4(5)IMZ derivativest hat might cleave DEDNPP.B oth inductivee ffects and hydrogen bonding by the substituents are shown to influence barriers and mechanisms.[a] Prof.Supporting information and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.

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“…Such substances are essential for productivity improvements, but are hardly biodegradable and accumulate in water bodies and soils, posing a threat to human and environmental health. , The lack of efficient inspection and regulation control for production, use, and discarding of pesticides is an aggravating factor in several countries, especially emerging-market economies, which severely contributes to increasing the global number of intoxication cases. In this context, Brazil is noted as the largest consumer of agrochemicals worldwide, disturbingly including numerous pesticides prohibited in Europe and the US due to the proven damaging effects. , On the other hand, efforts for more strict control of banned agrochemicals has led to the increase of obsolete stocks, which requires the development of efficient and sustainable process for converting pesticides into nontoxic products. − …”

Section: Introductionmentioning

confidence: 99%

Degradation of Organophosphates Promoted by 1,2,4-Triazole Anion: Exploring Scaffolds for Efficient Catalytic Systems

et al. 2021

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Organophosphate (OP) pesticides are responsible for numerous human deaths every year. Nucleophilic substitution is an important method to mitigate the toxicity of obsolete stocks of OPs. Herein, the degradation of O,O-diethyl-2,4-dinitrophenyl phosphate (DEDNPP) and pesticide diethyl-4-nitrophenyl phosphate (Paraoxon) promoted by 1,2,4-triazole (TAZ) was investigated by means of kinetic studies, nuclear magnetic resonance (NMR) analyses, and theoretical calculations. Results showed fast degradation of OPs is promoted by the anionic form of the nucleophile (TAZ(−)) in pH > 8.5 (optimal at pH = 11). Rate enhancements of 106 and 105-fold in relation to neutral hydrolysis of DEDNPP and Paraoxon were observed, respectively, consistent with alpha-nucleophiles reactivity. TAZ(−) regioselectively promotes the degradation of DEDNPP via P–O bond break, forming a quickly hydrolyzable phosphorylated intermediate, regenerating the nucleophile. Calculations using M06-2X/6-311++G(d,p) level of theory revealed that the equivalent nitrogen atoms of TAZ(−) are the main nucleophilic center of the molecule. This study expands the knowledge on the reactivity of iminic compounds as detoxificant agents of OPs, indicating the efficiency and selectivity of TAZ(−) in aqueous medium, encouraging the design of novel TAZ-based catalysts.

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Degrading Pesticides with Waste Product: Imidazole-Functionalized Rice Husk Catalyst for Organophosphate Detoxification

Cited by 5 publications

References 23 publications

From the Shelf to the Particle: Preparation of Highly Organic-Functionalized Magnetic Composites via 4-Nitrophenyl Reactive Ester

From the Shelf to the Particle: Preparation of Highly Organic-Functionalized Magnetic Composites via 4-Nitrophenyl Reactive Ester

Competitive Reactivity of Tautomers in the Degradation of Organophosphates by Imidazole Derivatives

Degradation of Organophosphates Promoted by 1,2,4-Triazole Anion: Exploring Scaffolds for Efficient Catalytic Systems

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