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Upstream product

• 122-14-5 MEP 
• 109-73-9 N-butylamine 
• 110-89-4 piperidine 

Relevant academic research and scientific papers

Microwave-assisted nucleophilic degradation of organophosphorus pesticides in propylene carbonate

Propylene carbonate is becoming a suitable green alternative to volatile organic solvents in the study of chemical reactions. In this study, an efficient method for nucleophilic degradation of five organophosphorus pesticides, fenitrothion, malathion, diazinon, parathion, and paraoxon, using propylene carbonate as a solvent is proposed. The effect of changing the nature of the nucleophile and the influence of microwave (MW) heating were investigated. A screening of temperatures (50 °C-120 °C) was performed under microwave heating. The pesticide degradation was followed by 31P NMR, and the extent of conversion (%) was calculated by the integration of phosphorus signals. Keeping in mind that recently it has been reported that some ionic liquids play a nucleophilic role, in this work we report for the first time the degradation of organophosphorus pesticides by using an amino acid-based ionic liquid such as Bmim[Ala] as a nucleophile and a bio-based solvent (propylene carbonate) as a reaction medium in combination with microwave heating. This journal is

Stabilization of the pesticide Fenitrothion toward O and N nucleophiles in the presence of cyclodextrins

The reaction of Fenitrothion with O and N nucleophiles (H2O2, NH2OH, n-butylamine and piperidine) was studied at 25°C in water containing 2% 1,4-dioxane in the presence of native cyclodextrins (α-, β-, and γ-CD). For all the nucleophiles, the presence of CD produces reaction inhibition with saturation kinetics. The greatest effect in all cases is observed with β-CD, and the greatest inhibition was observed for the reaction of Fenitrothion with H2O2 (81%), which is the most efficient nucleophile in promoting Fenitrothion degradation in homogeneous media. In the absence of CD, competition between the SN2(P) and the SN2(C) pathways was observed with piperidine as was reported before for the reaction with NH2OH and n-butylamine. The presence of β-CD does not modify product distribution in the case of the reaction with NH2OH and n-butylamine, whereas there is an increase in SN2(C) pathway when the nucleophile is piperidine.

Stabilization of the pesticide Fenitrothion toward O and N nucleophiles in the presence of cyclodextrins

The reaction of Fenitrothion with O and N nucleophiles (H2O2, NH2OH, n-butylamine and piperidine) was studied at 25°C in water containing 2% 1,4-dioxane in the presence of native cyclodextrins (α-, β-, and γ-CD). For all the nucleophiles, the presence of CD produces reaction inhibition with saturation kinetics. The greatest effect in all cases is observed with β-CD, and the greatest inhibition was observed for the reaction of Fenitrothion with H2O2 (81%), which is the most efficient nucleophile in promoting Fenitrothion degradation in homogeneous media. In the absence of CD, competition between the SN2(P) and the SN2(C) pathways was observed with piperidine as was reported before for the reaction with NH2OH and n-butylamine. The presence of β-CD does not modify product distribution in the case of the reaction with NH2OH and n-butylamine, whereas there is an increase in SN2(C) pathway when the nucleophile is piperidine.

Catalytic pathways in the ethanolysis of fenitrothion, an organophosphorothioate pesticide. A dichotomy in the behaviour of crown/cryptand cation complexing agents

The rates of displacement of 3-methyl-4-nitrophenoxide ion from the pesticide, fenitrothion, by alkali metal ethoxides in anhydrous ethanol were followed spectrophotometrically. Through product analysis experiments, which included 31P NMR and GC-MS, as well as spectrophotometric analysis, three reaction pathways were identified: nucleophilic attack at the phosphorus centre, attack at the aliphatic carbon, and a minor SNAr route (≤7%). Furthermore, a consecutive process was found to occur on the product of attack at the phosphorus centre. For purposes of kinetic treatment, the processes at the aliphatic and aromatic carbon were combined (i.e., the minor SNAr pathway was neglected), and the observed reaction rate constants were dissected into rate coefficients for nucleophilic attack at phosphorus and at aliphatic carbon. Attack at phosphorus was found to be catalyzed by the alkali metal ethoxides in the order KOEt > NaOEt > LiOEt. Catalysis arises from alkali metal ethoxide aggregates in the base solutions used (0-1.8 M); treatment of the system as a mixture of free ethoxide, ion-paired metal ethoxide, and metal ethoxide dimers resulted in a good fit with the kinetic data. An unexpected dichotomy in the kinetic behaviour of complexing agents (e.g., DC-18-crown-6, [2.2.2]cryptand) indicated that the dimers are more reactive than free ethoxide anions, which are in turn more reactive than ion-paired metal ethoxide. The observed relative order of reactivity is explained in the context of the Eisenman theory in which the free energy of association of the metal ion with the rate-determining transition state is largely determined by the solvent reorganization parameter. In contrast with displacement at the phosphorus centre, attack at the aliphatic carbon was not found to be catalyzed by alkali metals. In this case, the free ethoxide anion was more reactive than either the ion-paired metal ethoxide or the dimeric aggregate. The differing effects of alkali metals on the two pathways is ascribed largely to the leaving group pKa. For carbon attack, the pKa value estimated for demethyl fenitrothion, 2.15, is sufficiently low that metal ions are not required to stabilize the rate-determining transition state. In contrast, for phosphorus attack, 3-methyl-4-nitrophenoxide, with a pKa of 7.15, requires stabilization by metal ion interactions. Hence, alkali metal ions catalyze attack at phosphorus, but not attack at the carbon centres.

Stereochemistry of Aryl Methyl Phosphorochloridothionates as Chiral Two-step Phosphorylating Reagents

Seven aryl methyl phosphorochloridothionates were prepared and examined for reactivity as two-step phosphorylating reagents to synthesize oxazaphospholidine sulfide.The 2,6-dichloro-4-methylphenyl and p-nitrophenyl derivatives (CMPC and MNPC) were selecte