New heterogeneous B(OEt)3-MCM-41 catalyst for preparation of α,β-unsaturated alcohols

Titanium Dioxide as a Catalyst Support in Heterogeneous Catalysis

“…Heterogeneous catalysts have become a crucial part of many industrial activities, such as organic synthesis, oil refining, and pollution control [10–15]. Modern heterogeneous catalysts consist of several elements in precise proportions [12].…”

“…It is possible to improve the heterogeneous catalyst activity over modifying the support by approaches such as nanotechnology and nanoscience or controlling the pore structure [14–16]. For heterogeneous catalysis, the problem of catalyst separation and recovery from the reaction matrix are addressed by using various catalyst supports to immobilize the particle [15]. This in turn provides a large enough surface area for the heterogeneous catalyst for it not to dissolve into the solution matrix [16].…”

“…The idea is that the main catalyst should be dispersed on a suitable support to make the catalytic nanoparticles stable and obtain optimal performance and decrease the amount of costly metal being utilized, which accordingly decrease the total catalyst expenses [11, 15]. Furthermore, with porous characteristics, support materials offer a high dispersion of nanoparticle catalyst and simplify electron transfer, both of which contribute to better catalytic activities [17–20].…”

Selective Reduction of Ketones and Aldehydes in Continuous-Flow Microreactor—Kinetic Studies

“…The Inexpensive and non-toxic hydrogen donors and catalysts, mild reaction conditions, and exceptional chemoselectivity render this method of reduction favorable over alternatives. Among many active species, such as Zr [1,2], Al [3,4], Mg [3,5], and B [6,7], which are considered to be active catalysts for MPV reduction, zirconium has been shown to be one of the most promising. In the literature, batch processes are predominantly described with the use of numerous catalysts, e.g., homogeneous alkoxides [8,9], zeolites [10,11], mesoporous sieves [12][13][14], and hydrotalcite [15].…”

Synthesis of Highly Functionalized Allylic Alcohols from Vinyl Oxiranes and N-Tosylhydrazones via a Tsuji–Trost-Like “Palladium–Iodide” Catalyzed Coupling

“…Its construction has received intensive attention, because allylic alcohols are versatile precursors of various functionalities and moieties in organic synthesis. − Furthermore, they are exploited in the preparation of pharmaceuticals, fragrances, and agrochemicals. , Therefore, many efforts have been dedicated to their reactivity: metal-catalyzed allylic substitutions, − isomerizations, reductive couplings, radical allylations, , for instance. They are traditionally prepared via the chemoselective reduction of α,β-unsaturated carbonyl compounds , or the hydroalkenylation of ketones and aldehydes with preformed metalloalkenes. These alkenylmetal intermediates are generally prepared in situ through the reaction of alkenylhalides with a stoichiometric amount or an excess of metallic reagents (Mg, Li, Cu, and Zn), − or with Cr catalysts under reductive conditions, or through alkyne hydrometalation with metallic hydrides. , In recent years, many synthetic strategies that avoid the use of discrete metalloalkenes have been reported: metal-catalyzed alkene-carbonyl and alkyne–carbonyl reductive coupling, in addition to the redox-neutral alternative between alcohols and alkynes using Ru, Os, and Ni catalysts .…”