574-09-4Relevant academic research and scientific papers
Fabrication of NiFe layered double hydroxides using urea hydrolysis - Control of interlayer anion and investigation on their catalytic performance
Wu, Xu,Du, Yali,An, Xia,Xie, Xianmei
, p. 44 - 48 (2014)
NiFe layered double hydroxides (NiFe-LDHs) intercalated with nitrate and carbonate anion were synthesized by urea hydrolysis. The aging time and the molar ratio of NO3-/urea were varied in order to identify suitable parameters, which
Photoredox Catalytic Phosphite-Mediated Deoxygenation of α-Diketones Enables Wolff Rearrangement and Staudinger Synthesis of β-Lactams
Jiang, Zhiyong,Li, Haijun,Wei, Guo,Yang, Hui
supporting information, p. 19696 - 19700 (2021/08/03)
A novel visible-light-driven catalytic activation of C=O bonds by exploiting the photoredox chemistry of 1,3,2-dioxaphospholes, readily accessible from α-diketones and trialkyl phosphites, is reported. This mild and environmentally friendly strategy provides an unprecedented and efficient access to the Wolff rearrangement reaction which traditionally entails α-diazoketones as precursors. The resulting ketenes could be precisely trapped by alcohols/thiols to give α-aryl (thio)acetates and by imines to afford the valuable β-lactams in up to 99 % yields.
Aerobic oxidation of alcohols with air catalyzed by decacarbonyldimanganese
Meng, Shan-Shui,Lin, Li-Rong,Luo, Xiang,Lv, Hao-Jun,Zhao, Jun-Ling,Chan, Albert S. C.
supporting information, p. 6187 - 6193 (2019/11/20)
The oxidation of alcohols to carbonyl compounds using air as the terminal oxidant is highly desirable. As described in previous reports, the abstraction of α-H of the alcohol is the most important step, and it typically requires not only a metal catalyst but also complex ligands, co-catalysts and bases. Herein, we report a practical and efficient method for the oxidation of primary alcohols, secondary alcohols, 1,2-diols, 1,2-amino alcohols, and other α-functionalized alcohols using a commercially available catalyst, Mn2(CO)10, and no additives. Preliminary mechanistic studies indicated that an alkoxyl radical intermediate existed in our system, and a plausible mechanism consistent with the experimental results and literature was proposed.
Construction of Pd/BiOCl Catalyst for Highly-selective Synthesis of Benzoin Ethyl Ether by Chlorine Promoted Coupling Reaction
Yuan, Qinglin,Gong, Wanbing,Ye, Yixing,Liu, Jun,Lin, Yue,Chen, Chun,Zhang, Haimin,Li, Pengfei,Cheng, Weiren,Wei, Xiangjun,Liang, Changhao
, p. 2676 - 2682 (2019/05/27)
Exploring novel catalyst supports with unique performance creates more opportunity for transforming organic chemicals in heterogeneous catalysis. In this paper, BiOCl is first presented as an effective support for Pd nanoparticles (NPs) toward application in the coupling reaction of benzaldehyde. The Cl? ion dissociates from BiOCl, which forms nucleophile with Pd nanoparticles; this is key for the one-step synthesis of benzoin ethyl ether, the conversion and selectivity of which can reach to 100 % and 97.9 % at 100 °C, respectively. DFT calculations reveal that Cl? ions can be stabilized by stronger Bi?Cl bonds through doping of Fe ions in substituting Bi sites in BiOCl. The parallel catalytic evaluation using Pd/Fe-doped BiOCl catalyst shows the suppression of coupling reaction, conversely, demonstrating the crucial role of nucleophile. This work provides new insights into support tailoring for the synthesis of vital organic chemicals in heterogeneous catalysis by changing chemical reaction pathway.
Decomposition of a Β-O-4 lignin model compound over solid Cs-substituted polyoxometalates in anhydrous ethanol: acidity or redox property dependence?
Wu, Xuezhong,Jiao, Wenqian,Li, Bing-Zheng,Li, Yanming,Zhang, Yahong,Wang, Quanrui,Tang, Yi
, p. 1216 - 1228 (2017/07/10)
Production of aromatics from lignin has attracted much attention. Because of the coexistence of C–O and C–C bonds and their complex combinations in the lignin macromolecular network, a plausible roadmap for developing a lignin catalytic decomposition process could be developed by exploring the transformation mechanisms of various model compounds. Herein, decomposition of a lignin model compound, 2-phenoxyacetophenone (2-PAP), was investigated over several cesium-exchanged polyoxometalate (Cs-POM) catalysts. Decomposition of 2-PAP can follow two different mechanisms: an active hydrogen transfer mechanism or an oxonium cation mechanism. The mechanism for most reactions depends on the competition between the acidity and redox properties of the catalysts. The catalysts of POMs perform the following functions: promoting active hydrogen liberated from ethanol and causing formation of and then temporarily stabilizing oxonium cations from 2-PAP. The use of Cs-PMo, which with strong redox ability, enhances hydrogen liberation and promotes liberated hydrogen transfer to the reaction intermediates. As a consequence, complete conversion of 2-PAP (>99%) with excellent selectivities to the desired products (98.6% for phenol and 91.1% for acetophenone) can be achieved.
Organocatalytic Enantioselective Acyloin Rearrangement of α-Hydroxy Acetals to α-Alkoxy Ketones
Wu, Hua,Wang, Qian,Zhu, Jieping
supporting information, p. 5858 - 5861 (2017/05/12)
We report an unprecedented organocatalytic enantioselective acyloin rearrangement of α,α-disubstituted α-hydroxy acetals. In the presence of a catalytic amount of chiral binol-derived N-triflyl phosphoramide, α-hydroxy acetals rearranged to α-alkoxy ketones in good to high yields with high enantioselectivities. Formation of an ion pair between the in situ generated oxocarbenium ion and the chiral phosphoramide anion was proposed to be responsible for the highly efficient transfer of chirality. Conditions for removal of cyclohexyl and cyclopentyl groups from the corresponding α-alkoxy ketones were uncovered underpinning their potential general utility as hydroxy protecting groups. Conversion of the rearranged products to the enantioenriched α-hydroxy ketone, 1,2-diol, β-amino alcohol and 1,4-dioxane was also documented.
On the Mesoporogen-Free Synthesis of Single-Crystalline Hierarchically Structured ZSM-5 Zeolites in a Quasi-Solid-State System
Ge, Tongguang,Hua, Zile,He, Xiaoyun,Lv, Jian,Chen, Hangrong,Zhang, Lingxia,Yao, Heliang,Liu, Ziwei,Lin, Chucheng,Shi, Jianlin
, p. 7895 - 7905 (2016/06/09)
Hierarchically structured zeolites (HSZs) have gained much academic and industrial interest owing to their multiscale pore structures and consequent excellent performances in varied chemical processes. Although a number of synthetic strategies have been developed in recent years, the scalable production of HSZs single crystals with penetrating and three-dimensionally (3-D) interconnected mesopore systems but without using a mesoscale template is still a great challenge. Herein, based on a steam-assisted crystallization (SAC) method, we report a facile and scalable strategy for the synthesis of single-crystalline ZSM-5 HSZs by using only a small amount of micropore-structure-directing agents (i.e., tetrapropylammonium hydroxide). The synthesized materials exhibited high crystallinity, a large specific surface area of 468 m2 g-1, and a pore volume of 0.43 cm3 g-1 without sacrificing the microporosity (≈0.11 cm3 g-1) in a product batch up to 11.7 g. Further, a kinetically controlled nucleation-growth mechanism is proposed for the successful synthesis of single-crystalline ZSM-5 HSZs with this novel process. As expected, compared with the conventional microporous ZSM-5 and amorphous mesoporous Al-MCM-41 counterparts, the synthesized HSZs exhibited significantly enhanced activity and stability and prolonged lifetime in model reactions, especially when bulky molecules were involved.
Dual-mesoporous ZSM-5 zeolite with highly b-axis-oriented large mesopore channels for the production of benzoin ethyl ether
Zhou, Xiaoxia,Chen, Hangrong,Zhu, Yan,Song, Yudian,Chen, Yu,Wang, Yongxia,Gong, Yun,Zhang, Guobin,Shu, Zhu,Cui, Xiangzhi,Zhao, Jinjin,Shi, Jianlin
, p. 10017 - 10023 (2013/08/23)
Dual-mesoporous ZSM-5 zeolite with highly b axis oriented large mesopores was synthesized by using nonionic copolymer F127 and cationic surfactant CTAB as co-templates. The product contains two types of mesopores - smaller wormlike ones of 3.3 nm in size
Pt nanoparticles entrapped in ordered mesoporous carbons for liquid-phase hydrogenation of unsaturated compounds
Ding, Yue,Li, Xiaohong,Li, Bo,Wang, Haihong,Wu, Peng
, p. 147 - 151 (2013/01/14)
Pt nanoparticles entrapped in ordered mesoporous carbons were proved effective for liquid-phase hydrogenation of benzaldehyde and its derivatives in water. Due to higher hydrophobicity, Pt/CMK-3 catalyst was slightly superior to Pt/CMK-8 catalyst towards benzaldehyde hydrogenation. Nevertheless, the larger pore volume of Pt/CMK-8 catalyst is more beneficial for mass transfer of benzaldehyde derivatives. In addition, the surface electronic state of Pt particles deposited on CMK-8 is helpful for the activation of carbonyl compounds. Therefore, the Pt/CMK-8 and Pt/CMK-3 catalysts showed tiny differences in most cases. The Pt catalysts can also catalyze the hydrogenation of olefins and other carbonyl compounds.
Reactions of ZnR2 compounds with dibenzoyl: Characterisation of the alkyl-transfer products and a striking product-inhibition effect
Dranka, Izabela,Kubisiak, Marcin,Justyniak, Iwona,Lesiuk, Micha?,Kubicki, Dominik,Lewiński, Janusz
experimental part, p. 12713 - 12721 (2011/12/15)
The first systematic theoretical and experimental studies of reaction systems involving ZnR2 (R=Me, Et or tBu) with dibenzoyl (dbz) as a non-innocent ligand revealed that the character of the metal-bonded R group as well as the ratio of the reagents and the reaction temperature significantly modulate the reaction outcome. DFT calculations showed four stable minima for initial complexes formed between ZnR2 and dbz and the most stable structure proved to be the 2:1 adduct; among the 1:1 adducts three structural isomers were found of which the most stable complex had the monodentate coordination mode and the chelate complex with the s-cis conformation of the dbz unit appeared to be the least stable form. Interestingly, the reaction involving ZnMe2 did not lead to any alkylation product, whereas the employment of ZntBu2 resulted in full conversion of dbz to the O-alkylated product [tBuZn{PhC(O)C(OtBu)Ph}] already at -20-°C. A more complicated system was revealed for the reaction of dbz with ZnEt2. Treatment of a solution of dbz in toluene with one equivalent of ZnEt 2 at room temperature afforded a mixture of the O- and C-alkylated products [EtZn{PhC(O)C(OEt)Ph}] and [EtZn{OC(Ph)C(O)(Et)Ph}], respectively. The formation of the C-alkylated product was suppressed by decreasing the initial reaction temperature to -20-°C. Moreover, in the case of the dbz/ZnEt 2 system monitoring of the dbz conversion over the entire reaction course revealed a product inhibition effect, which highlights possible participation of multiple equilibria of different zinc alkoxide/ZnEt2 aggregates. Diffusion NMR studies indicated that dbz forms an adduct with the O-alkylated product, which is a competent species for executing the inhibition of the alkylation event. It all depends on R: The first systematic theoretical and experimental study of ZnR2 (R=Me, Et or tBu) with dibenzoyl revealed that the character of the metal-bonded alkyl group as well as the reaction conditions (e.g., ratio of the reagents, temperature) modulate the reaction outcome (see scheme). Monitoring the dibenzoyl conversion over the reaction course revealed a product-inhibition effect, which highlights possible participation of multiple equilibria of different zinc alkoxide/ZnR2 aggregates.
