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Interaction Mechanisms Between Biochar and Herbicides
Published in Kassio Ferreira Mendes, Interactions of Biochar and Herbicides in the Environment, 2022
Rodrigo Nogueira de Sousa, Matheus Bortolanza Soares, Felipe Hipólito dos Santos, Camille Nunes Leite, Kassio Ferreira Mendes
At the end, a particular case of possible interaction between biochar and herbicide is nucleophilic addition and substitution. A nucleophile is a chemical species capable of donating a pair of electrons to form a bond. Generally, any ion or molecule with a free electron pair or at least one π bond can act as a nucleophile (Mayr and Patz 1994; Ritchie 1972). Nucleophilic addition is the interaction of a nucleophile with an unsaturated chemical compound (double or triple bond), resulting in the formation of a saturated compound. In the nucleophilic addition reaction, the π bond of the substrate gives rise to two new bonds of a covalent character (Swain and Scott 1953). The nucleophilic addition and substitution mechanism are exemplified in Figure 4.16.
Terms and Definitions
Published in Rick Houghton, William Bennett, Emergency Characterization of Unknown Materials, 2020
Rick Houghton, William Bennett
According to the Lewis definition, an acid is an electron pair acceptor and a base is an electron pair donor. Lewis acids are electrophiles and Lewis bases are nucleophiles. The Lewis definition is used extensively in organic chemistry because a molecule that is an electrophile (electron lover) can have an area of partial positive charge, which will attract an electron. A nucleophile has a partial negative charge, which attracts an electrophile. Lewis acids include substances with no transferable H+ and a Lewis base includes substances with no transferable OH–.
Alkenes and Alkynes: Structure, Nomenclature, and Reactions
Published in Michael B. Smith, A Q&A Approach to Organic Chemistry, 2020
A nucleophile is an electron rich species that donates two electrons to a carbon to form a new covalent bond. When a carbocation such asB from 2-methylprop-1-ene in the preceding question is formed, what can it react with?
Functional graphene oxide for organic pollutants removal from wastewater: a mini review
Published in Environmental Technology, 2022
Qiaoping Kong, Hongzheng Zhang, Yunlong Lan, Xueqing Shi, Zilong Fang, Qi Chang, Jun Liu, Chaohai Wei
The epoxy groups on the surface of GO have high reactivity and can react with some amino compounds by nucleophilic ring-opening substitution. In addition to the compounds with amino groups, the epoxy groups can also react with other groups. The epoxy groups on GO are easy to be attacked by nucleophilic group, which leads to nucleophilic substitution reaction and ring-opening. The most commonly used nucleophiles are those substances containing amino groups, such as long-chain alkyl amines, ionic liquid amines and siloxanes. For example, Yang et al. [68] obtained polydisperse chemically converted graphene (p-CCG) sheets via a nucleophilic ring-opening reaction between the epoxy groups in GO and the amine groups in 3-methylimidazolium bromide (IL-NH2) (Figure 2(a)). Besides, 3-aminopropyltriethoxysilane (APTS) was also used to modify GO to prepare functionalized chemically converted graphene (f-CCG) via facile covalent functionalization of GO (Figure 2(b)) [69]. In this process, the covalent functionalization of GO was mainly through the reaction between epoxy groups in GO and amino moieties in APTS.
The effect of substituents on the reactivity of dichloridotriphenylphosphinoruthenium(II) complexes: kinetic and mechanistic study
Published in Journal of Coordination Chemistry, 2021
Meshack K. Sitati, Gershom Kyalo Mutua, Daniel O. Onunga, Deogratius Jaganyi, Allen Mambanda
Generally, for both k2 and the value of the activation enthalpy increases as the bulkiness of the thiourea entering ligand increases, which must be related to the increasing steric hindrance encountered by the entering ligand that increases the activation enthalpy barrier. In terms of the activation entropy, there is a general trend of going from more negative to more positive values on increasing the steric hindrance of the entering thiourea nucleophile. This can be interpreted in terms of a steady changeover from an associative interchange mechanism (Ia) to a more dissociative interchange (Id) mechanism on increasing steric hindrance [44,45]. The trend in reactivity of the nucleophiles was TU > DMTU > TMTU. This can be accounted for in terms of steric factors where reactivity decreases with increase in steric hindrance of the nucleophile.
Electrochemical and quantum chemical investigation to evaluate corrosion inhibition performance of therapeutic drug
Published in Canadian Metallurgical Quarterly, 2023
Sandesh Shetty, Padmalatha Rao, Namitha Kedimar, Suma A. Rao
The data obtained from the Fukui indices analysis is given in Table 10. It helps to identify the reactivity of the molecule. f+ value of KYN are located in H41, H46, H49, H50, H51, H52, H53, H54, H56, H61, H62, H67, H68, H69. These atoms accept electrons and act as electrophiles. f- the value of KYN is located in N8, O9, H40, and H42. These atoms donate electrons and act as nucleophiles.