GUNJAN P DESHMUKH
Articles written in Journal of Chemical Sciences
Volume 129 Issue 11 November 2017 pp 1677-1685 REGULAR ARTICLE
2-Methyl-4-chlorophenoxy propionic acid (Mecoprop) is a widely used household herbicide. In the current work, a simple synthetic method is developed for Mecoprop methyl ester using solid-liquid phase transfer catalysis (S-L PTC) with K₂CO₃ as mild base and toluene as solvent. Conversion of 95% was achieved with 100% selectivity for Mecoprop ester at 100 ◦C. Simple isolation process was employed to recover the product from the reaction mixture. A reaction mechanism was proposed and new kinetic model developed involving one liquid and two solid co-products. The activation energy for the reaction was calculated. This is the first example of its kind being reported vis-à-vis kinetics and mechanism.
Volume 129 Issue 11 November 2017 pp 1761-1769 REGULAR ARTICLE
An efficient method for the synthesis of quinoxaline derivatives through oxidative coupling of o-phenylenediamines (OPD) with terminal alkynes by using copper-alumina (Cu-Al) catalyst was described. A series of Cu-Al catalysts with different mole ratios of Cu ²⁺ /Al ³⁺, 2:1 (Cu-Al-1), 2.5:1 (Cu-Al-2) and 3:1 (Cu-Al-3) were prepared by co-precipitation method followed by calcination and their activity was checked for the synthesis of quinoxaline derivatives. Cu-Al-2 showed excellent activity at 60 ◦C in presence ofK ₂CO ₃. The catalyst is inexpensive, recyclable and environmentally benign. The fresh and recycled catalysts were characterized by different analytical techniques. Different reaction parameters were optimized; catalyst screening, solvent, base and temperature. The protocol was extended towards different substrates.
Volume 134, 2022
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