Mesoporous alumina sulphuric acid: A novel and efficient catalyst for on-water synthesis of functionalized 1,4-dihydropyridine derivatives via β-enaminones

Using innovative copper-loaded activated alumina (Cu/AA) as the catalyst for catalytic wet peroxidation (CWPO) of catechol

In this study, copper-loaded activated alumina (Cu/AA) was synthesized and used for the CWPO of catechol (a representative refractory organic pollutant). Various characterization techniques were deployed to characterize the catalysts, e.g., activated alumina (AA), as well as pristine and spent 1% Cu/AA. The innovative 1% Cu/AA catalyst exhibited good thermal stability up to 1173 K with a marginal weight loss of 13%. The Cu species were well dispersed on the activated alumina framework with no significant cluster formation. Typically, the average copper particle size of 5 nm was dispersed on the AA framework. Catechol removal was observed to be 92% with 87% mineralization at optimized conditions (initial catechol concentration = 200 mg/L, catalyst dose of 1% Cu/AA = 2 g/L; temperature = 323 K; pH = 6; and H₂O₂/catechol stoichiometric ratio = 0.5). The mineralization of catechol was analyzed using mass spectroscopy, with the associated mechanism has been elucidated. Results of this study indicated that synthesized catalyst has phenomenal advantages in terms of simple separation and high removal efficiency of catechol, suggesting the feasibility of employing Cu/AA as the effective catalyst for the CWPO of catechol.

Sulphated alumina tungstic acid (SATA): a highly efficient and novel heterogeneous mesostructured catalyst for the synthesis of pyrazole carbonitrile derivatives and evaluation of green metrics

A novel mesostructured catalyst sulphated alumina tungstic acid (SATA) has been prepared by an easy route. Various techniques such as IR, XRD, SEM, EDX, TEM, TGA and BET were used to characterize the synthesized catalyst. The catalytic activity of the meso material has been explored by synthesizing a series of new pyrazole carbonitrile derivatives from aromatic aldehydes, ethylcyanoacetate, phenylhydrazine/hydrazine hydrate in ethanol under reflux conditions. Furthermore, the “greenness” of this protocol when estimated by green metrics, displayed satisfactory results. The protocol is free from column chromatography, and toxic solvents and is more efficient as compared to reported ones.

A novel mesostructured catalyst sulphated alumina tungstic acid (SATA) has been prepared by an easy route.

Direct Synthesis of Nitriles from Aldehydes and Hydroxylamine Hydrochloride Catalyzed by a HAP@AEPH2-SO3H Nanocatalyst

We describe an efficient method for the direct preparation of nitriles from aldehydes and hydroxylamine hydrochloride catalyzed by sulfonated nanohydroxyapatite functionalized by 2-aminoethyl dihydrogen phosphate (HAP@AEPH2-SO3H) as an eco-friendly and recyclable solid acid nanocatalyst. In this protocol the use of a solid acid nanocatalyst provides a green, useful, and rapid method for the preparation of nitriles in excellent yields. In addition, the notable feature of this methodolgy is that the synthesized nanocatalyst can be recovered and reused five times without any noticeable loss of efficiency.

Sulfonated nanohydroxyapatite functionalized with 2-aminoethyl dihydrogen phosphate (HAP@AEPH2-SO3H) as a new recyclable and eco-friendly catalyst for rapid one-pot synthesis of 4,4′-(aryl methylene)bis(3-methyl-1H-pyrazol-5-ol)s

HAP@AEPH₂-SO₃H, a new, green, solid acid catalyst, was prepared, characterized and applied for the synthesis of 4,4′-(aryl methylene)bis(3-methyl-1H-pyrazol-5-ol)s.

Dy/chitosan: a highly efficient and recyclable heterogeneous nano catalyst for the synthesis of hexahydropyrimidines in aqueous media

Dy(iii)/chitosan as a recyclable and heterogeneous catalyst is used for the sustainable preparation of hexahydropyrimidine derivatives in aqueous media.

Design of a graphene oxide-SnO2 nanocomposite with superior catalytic efficiency for the synthesis of β-enaminones and β-enaminoesters

A graphene–SnO₂ nanocomposite has been synthesized by a solvothermal method, which is a more effective and less time-consuming catalyst for the synthesis of β-enaminones and β-enaminoesters.