Preparation of NbOx/SiO2-coated structured packing material and it's catalytic performance in the gas-phase Beckmann rearrangement of cyclohexanone oxime to ε-caprolactam

[1,3]/[1,4]-Sulfur atom migration in β-hydroxyalkylphosphine sulfides

“…Among all organic reactions, rearrangements are an exciting class of transformations where unusual or even unexpected products can be obtained. Many rearrangements are of practical use in synthetic organic chemistry, including Beckmann [1][2][3][4], Claisen [5][6][7][8], pinacol [9][10][11][12], Wagner-Meerwein [13][14][15][16], Curtius [17][18][19][20], Hofmann [21][22][23][24], Overmann [25][26][27][28] rearrangements, and many others. In organophosphorus chemistry, rearrangements are less developed transformations, however, some examples can be found in the literature (Scheme 1).…”

“…In organophosphorus chemistry, rearrangements are less developed transformations, however, some examples can be found in the literature (Scheme 1). These include the famous Arbuzov rearrangement [29][30][31][32] as well as phospha-Fries ( [1,3]-rearrangements) [33][34][35][36][37], phospha-Brook ( [1,2]-rearrangement) [38][39][40][41][42], and [2,3]-sigmatropic rearrangements of propargyl and allylphosphinites [43][44][45][46].…”

“…Other [1,2]-rearrangements include α,β-epoxyphosphonate opening [47], β-halo-α-hydroxyphosphonate rearrangement [48], phosphirene rearrangement [49], or the unusual phosphonate-phosphinate rearrangement of dimethyl phosphonates [50]. Other [1,3]-rearrangements of organophosphorus compounds include phosphoenolpyruvate formation from phosphonopyruvate [51], benzylphosphonium salt formation from the corresponding o-methylaryl-substituted precursors [52], or the formation of ketophosphonates from vinylphosphates [53].…”

A modified mixed‐acid catalytic system for Beckmann rearrangement of cyclohexanone oxime

“…Previous research about the rearrangement reaction focuses on the process without producing ammonium sulfate, and relevant synthesis methods toward CPL have been continuously studied, which are vaporphase Beckmann rearrangement over solid catalysts [5][6][7][8] and liquid-phase Beckmann rearrangement over solid, [9][10][11][12] ionic liquid, [13][14][15][16] or organic catalysts. [17][18][19][20] However, the vapor-phase process suffers the problems of low selectivity and catalyst deactivation, and the current liquid-phase process is restricted by the problems of poor efficiency, low selectivity, and catalyst recycling, thereby limiting their industrial application.…”

Preparation of para-Aminophenol from Nitrobenzene through Bamberger Rearrangement Using a Mixture of Heterogeneous and Homogeneous Acid Catalysts

“…Heterogeneous niobium-based catalysts have also been reported to catalyze similar reactions; however, they have been largely underexploited. Nevertheless, they have recently found applications in the hydrolysis of saccharose, the lactonization of ethyl levulinate, and in the Beckman rearrangement . However, to the best of our knowledge, (supported) niobium catalysts have never been employed for the Bamberger rearrangement of PHA to PAP.…”