Volcanic ash as reusable catalyst in the green synthesis of 3H-1,5-benzodiazepines

Abstract

The volcanic ash from the Andes mountain range (Puyehue-Cordon Caulle volcanic complex situated in western South America on the Argentinean-Chilean border) was used as heterogeneous acid catalyst in the suitable synthesis of 3H-1,5-benzodiazepines. The natural ashes were classified according to their particle size to generate the different catalytic materials. The catalysts were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS), vibrational spectroscopies (FT-IR and Raman), and textural properties were determined by N2 adsorption (SBET). Potentiometric titration with n-butylamine was used to determine the acidic properties of the catalytic materials. Several 3H-1,5-benzodiazepines were obtained by reaction of o-phenylenediamine and substituted 1,3-diphenyl-1,3-propanedione in solvent-free conditions, giving good to excellent yields of a variety benzodiazepines. The method was carried out in environmentally friendly conditions and it was operationally simple. The volcanic ash resulted in a safe and recyclable catalyst.

Inexpensive Volcanic Ash Catalyst for Pyrolysis of Plastic Waste into Fuel Using Sequential Thermo-Catalytic Reactor

“…The mesoporous size of such as majority of catalysts is suitable to be utilized for long-chain hydrocarbon cracking or short-chain hydrocarbon formation. Thus the two volcanic ash samples (inactivated and activated) are worthy to be used as a catalyst, as also reported by Vargas et al, 2021 and Munoz et al, 2019 [17,29].…”

“…The large size and number of pores construct space for the uid to ow, resulting in greater adsorption capacity. Owing to the pore diameter is also directly proportional to the pore volume, the larger the pore diameter in volcanic ash, the larger the pore volume and the greater the adsorption capacity [27,29]. The mesoporous size of such as majority of catalysts is suitable to be utilized for long-chain hydrocarbon cracking or short-chain hydrocarbon formation.…”

“…The results of the EDS spectrum analysis from activated VA samples are shown in [29]. Dealumination of VA with activation through acid treatment will increase the ratio of Si/Al.…”

“…Analysis of surface structure and morphology as well as compound composition of inactive and activated VA was carried out using SEM-EDS. The VA surface morphology analysis was observed from SEM, while the elemental composition was searched from the EDS diffractogram spectrum [29]. The results of the VA SEM micrographs with a magni cation of 5000 times are presented in Fig.…”

Synthetic aspects of 1,4- and 1,5-benzodiazepines usingo-phenylenediamine: a study of past quinquennial

“…Muñoz and co-workers 70 developed a green method for the synthesis of 3 H -1,5-BZDs ( 12 ), in which volcanic ash was used as a heterogenous acid catalyst. The catalyst was found from the Andes mountain range.…”