Robust and Environmentally Benign Solid Acid Intercalation Catalysts for the Aminolysis of Epoxides

Abstract

The catalytic aminolysis of epoxides can lead to a large number of β‐amino alcohols which are of particular interest in industrial applications. In this paper, we demonstrate for the first time the use of a polyoxometalate [CoW12O40]5− intercalated layered double hydroxides (Zn3Al‐LDH) material as an efficient solid acid catalyst for the catalytic aminolysis of various epoxides under mild and solvent‐free conditions. The as‐prepared heterogeneous catalyst Zn3Al‐CoW12 was fully characterized by FT‐IR, powder XRD, TG‐DTA, BET, XPS, SEM, HR‐TEM and NH3‐TPD. The catalytic performance of Zn3Al‐CoW12 for the aminolysis of epoxides revealed excellent yields with high regioselectivity and stereoselectivity. Moreover, the solid acid catalyst can be easily recycled and reused without detectable decrease of its catalytic efficiency.

Direct α-Imination of N-Acyl Pyrazoles with Nitrosoarenes

“…The basic approach to prepare β-amino alcohols of type 10 relies on ring opening of styrene epoxides by anilines. Hence, control of the regioselectivity turns out to be a challenging issue to address, and usually a mixture of regioisomeric β-amino alcohols is observed . In contrast, the one-pot route illustrated in Scheme enables the selective preparation of β-amino alcohols 10 in good to excellent yields .…”

Ultra-small porous WN/W2C nanoparticles for sustained hydrogen production by a polyoxometalate-intercalated pyrolysis strategy

“…S1, ESI†) agree well with the literature, further demonstrating the successful synthesis of the intercalated layers. 32 The SEM (Fig. S2a, ESI†) and TEM (Fig.…”

Insight into the In-Situ Encapsulation-Reassembly Strategy To Fabricate PW12@NiCo-LDH Acid–Base Bifunctional Catalysts

“…The prepared PW 12 @NiCo-LDH possessed both acidic and basic properties, which were determined by NH 3 - and CO 2 -temperature-programmed desorption (TPD), respectively. As shown in NH 3 -TPD curve (Figure S9a), the PW 12 @NiCo-LDH exhibited a NH 3 desorption peak with a maximum at 298 °C, which was associated with the adsorption of NH 3 molecules on the PW 12 species, indicating the presence of medium acid sites. , In the CO 2 -TPD curve of PW 12 @NiCo-LDH (Figure S9b), three CO 2 desorption peaks can be observed at 94, 363, and 492 °C . These peaks were attributed to the weak basic sites from −OH groups on the surface, the medium basic sites were associated to the oxygen of M–O pairs, and strong basic sites caused by the coordinately unsaturated O 2 – ions of NiCo-LDH. , The unsaturated coordination O 2 – ions originated from the metal vacancies generated during the in-situ encapsulation-reassembly process, which were evidenced by the relatively low coordination numbers of the Ni–M shell and the Co–M shell in PW 12 @NiCo-LDH.…”

“…Considering the strong interaction between PW 12 and NiCo-LDH, and the variation of the coordination number of Ni–O and Co–O shells, we anticipated four possible locations of PW 12 as the following. For model 1 (named PW 12 @NiCo-LDH-V free ), PW 12 can be assembled with NiCo-LDH without vacancies, and there were electrostatic and hydrogen bonding interactions between PW 12 and NiCo-LDH layers , (Figure a). For models 2 and 3 (named PW 12 @NiCo-LDH-V Ni and PW 12 @NiCo-LDH-V Co ), PW 12 was located around the Ni/Co vacancy of NiCo-LDH to simulate the adsorption of PW 12 by Ni/Co vacancies (Figure b,c).…”