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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.
Bifunctional Porous Catalysts in the Synthesis of Valuable Products
Published in Vanesa Calvino-Casilda, Antonio José López-Peinado, Rosa María Martín-Aranda, Elena Pérez-Mayoral, Nanocatalysis, 2019
Elena Pérez-Mayoral, Marina Godino-Ojer, Daniel González-Rodal
There are a lot of studies focused on the catalytic nucleophilic addition reactions. The nucleophile activation often is produced by the abstraction of acidic protons onto carbonylic systems and related compounds containing a-hydrogen atoms, whereas the activation of the electrophile occurs by the lowering of the LUMO levels by interaction with acidic catalysts exhibiting Brønsted or Lewis characters. In this context, organic amines immobilized onto the inorganic solid–acid surfaces provide highly active acid–base bifunctional catalysts active in various organic transformations.
Thermodynamic modelling of the nature of speciation and phase behaviour of binary and ternary mixtures of formaldehyde, water and methanol
Published in Molecular Physics, 2023
Malak Wehbe, Andrew J. Haslam, Salvador García-Muñoz, George Jackson, Amparo Galindo
Reaction (1) is a nucleophilic addition reaction in which water acts as a nucleophile, attracted by the partial positive charge of the carbon atom in the carbonyl group in formaldehyde, to form MG; this is represented by configuration I in Figure 3(a). Here, however, we model all the possible association schemes that would lead to the formation of an MG aggregate in the SAFT-γ Mie model (cf. Figure 3(a)). In order to determine the true mole fraction of MG, we sum the probability of each configuration forming. For each MG configuration, we multiply the probability that the two corresponding association sites in Figure 3(a) are bonded with the probability that no other sites on formaldehyde can bond to the bonded site-type on water.
Dispersion of graphene oxide and its application prospect in cement-based materials: a review
Published in Journal of Dispersion Science and Technology, 2023
Huangqi Wang, Liran Zhang, Dongmin Wang, Danhua Geng, Ming Zhang, Wenqian Du, Huixin Chen
Due to the high electronegativity of oxygen, the C = O and C–O–C electron clouds of carbonyl and epoxy groups, respectively, shift toward oxygen, causing a partial positive charge on C and making it the likely target for nucleophilic addition/substitution. Yuan et al.[74] used phenol and formaldehyde to react with epoxy groups on GO for functionalization and advance phenolic polycondensation to prepare GO-phenolic resin composites (Figure 7h). Collins et al.[75] used sodium malononitrile to react with epoxy groups to introduce nitrile groups on GO to improve GO dispersion and solubility. Grignard reagents are among the more important nucleophilic reactions for aldehyde/keto groups and epoxy groups. This reaction introduces a multitude of structures and contributes to GO functionalization. Huang et al.[76] reacted GO with Grignard reagent, such as C4H9MgCl (BuMgCl), to generate precursors for Ziegler–Natta polymerization (Figure 7j). Due to the selectivity of the special reaction, this type of reaction could introduce some functional groups into the special position in GO, which is an important method to stable functionalization of GO itself.
Bioinspired and green water repellent finishing of textiles using carnauba wax and layer-by-layer technique
Published in The Journal of The Textile Institute, 2020
Azadeh Bashari, Amir H. Salehi K., Niloofar Salamatipour
In this study, Reactive Black KNB (RB-KNB) as a di-azo vinyl sulphonic dye was covalently attached to the cotton fibers surface via a nucleophilic addition reaction and then chemically reduced to obtain aromatic amines with attached reactive dye molecules. RB-KNB was chosen because it was cheap and the most widely used dye in the textile (Kim, Zille, Murkovic, Güebitz, & Cavaco-Paulo, 2007). As shown in Figure 5, three amino groups are produced after the reductive cleavage of the two azo groups. One of the amino groups is covalently linked to the cellulose chain and the others containing amino groups are being solubilized in water. During the reduction process with sodium dithionite, due to break the azo bonds and the formation of the colorless amines, the fabric is decolorized.