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Mn(II) and Zn(II) Containing Linseed Oil-Based Poly (Ester Urethane) as Protective Coatings
Published in Lionello Pogliani, Suresh C. Ameta, A. K. Haghi, Chemistry and Industrial Techniques for Chemical Engineers, 2020
Eram Sharmin, Manawwer Alam, Deewan Akram, Fahmina Zafar
The reaction occurs both at hydroxylic and carboxylic ends of Lpol. The first step follows addition–elimination reaction at the carbonyl carbon of the carboxylic acid terminated end of Lpol and metal acetate. The reaction results in the incorporation of metal in Lpol backbone. The first step involves addition reaction at carbonyl carbon of Lpol leading to tetrahedral transition state developing partial negative charge on oxygen (from initial trigonal state), followed by the formation of tetrahedral intermediate. The latter then undergoes ejection reaction (of –OH) returning to initial trigonal state resulting in overall nucleophilic acyl substitution by addition-ejection/elimination reaction at the carbonyl carbon of carboxylic acid terminated end of Lpol. The reaction at hydroxylic end occurs by attack on carbonyl carbon of metal acetate, forming metal oxide.17–25
Hydrolysis
Published in Richard A. Larson, Eric J. Weber, Reaction Mechanisms in Environmental Organic Chemistry, 2018
Richard A. Larson, Eric J. Weber
Hydrolysis at unsaturated carbon occurs by a two-step process: (1) nucleophilic addition at the acyl group [RC(O)] to give a tetrahedral intermediate (2.52) and (2) elimination of the leaving group (2.53). This reaction mechanism is referred to as the addition-elimination mechanism or nucleophilic acyl substitution. () ()
Synthesis and characterization of the Co(II) and Ni(II) complexes of 1,3,4-thiadiazole-derived ketones and secondary alcohols: thermal and magnetic properties
Published in Journal of Coordination Chemistry, 2021
Melih Erdogan, Kubra Kiymaz, Hakan Tahtaci, Saban Uysal
In the second step of the study, N-(5-((2-(3,4-dichlorophenyl)-2-oxoethyl)thio)-1,3,4-tiadiazole-2-yl)benzamide derivatives (5a-j) were synthesized by reaction of 3 with various benzoyl chloride derivatives (4a-j) in the presence of pyridine with yields varying between 65% and 84%. These reactions are typical nucleophilic acyl substitution reactions that occur through nucleophilic addition and elimination to the carbonyl carbon. Acyl groups produce substitution reactions, as expected. Chlorine that has bonded to the carbonyl carbon can be removed by protonation if necessary. Acyl chlorides usually react by losing the chloride ion, a very good leaving group. The lone electron pair on the amino group in 3 attacks the carbonyl carbon of the acyl derivatives (4a-j) as a nucleophile. A proton from the amino group transfers to chloride and the electron pair on oxygen attacks the carbon to form a double bond, with hydrogen chloride turning into pyridinium chloride salt. After the reaction is completed, when the raw materials formed are washed with a large amount of water, pyridinium chloride is removed from the medium. The proposed reaction mechanism for formation of 5a-j is given in Figure 2.