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231.
Rahul Kalita Wahida Begum Poorvi Gupta Manav Chauhan Naved Akhtar Rajashree Newar Prof. Dr. Kuntal Manna 《欧洲无机化学杂志》2023,26(25):e202300215
Oxidation of alkenes to carbonyls or diols compounds is important in synthesizing fine chemicals and pharmaceutical intermediates. We report the synthesis and characterization of an aluminum metal-organic framework node-supported copper(II) chloride (DUT-5-CuCl), which is an efficient heterogeneous catalyst for the oxidation of alkenes using H2O2 as an oxidizing agent. Styrene and various substituted styrenes were transformed into the corresponding carbonyl compounds in excellent selectivity and yields. DUT-5-CuCl is tolerant with various functional groups and could be recycled and reused at least 5 times in the oxidation of α-methylstyrene. Unlike the oxidation of styrene derivatives, DUT-5-Cu catalyzed oxidation of aliphatic and cyclic alkenes produced 1,2-diols compounds selectively. The mechanism of the DUT-5-Cu catalyzed oxidation of styrene to benzaldehyde was investigated in detail by various experiments such as the determination of reaction intermediates and characterization of the catalyst after catalysis, and computational studies. This work highlights the importance of MOF-supported earth-abundant metal catalysts for oxidation reactions to produce fine chemicals. 相似文献
232.
二氧化碳加氢合成低碳烯烃反应平衡体系热力学研究 总被引:13,自引:0,他引:13
随着世界工业的发展,含碳物质氧化的最终产物CO2的排放量与日俱增,CO2温室气体对环境的污染已引起人们广泛的关注. 研究证明,CO2可作为单体转化为烃进行二次利用,是最有前景的抑制其大量排放的途径. 在化学反应工程上,热力学研究可以为反应体系提供一个反应物转化率的理论最大值,从而更加清楚地认识这一反应体系,为衡量催化剂的效果提供有利的尺度,进而指导催化剂的开发工作. 对CO2加氢合成低碳烯烃反应体系平衡时进行了热力学研究,通过数学方法对催化作用下反应体系的热力学参数进行求解,分析了反应体系平衡时各相的平衡组成及其同温度、压力和氢/碳比之间的关系. 结果表明,CO2理论最高转化率为69%~71%. 相似文献
233.
234.
John J. Molloy Tobias Morack Ryan Gilmour 《Angewandte Chemie (International ed. in English)》2019,58(39):13654-13664
Strategies to achieve spatiotemporal regulation of pre‐existing alkenes via external stimuli are essential given the ubiquity of feedstock olefins in chemistry and their downstream applications. Mirroring the 1‐0 switch that underpins mammalian vision through selective geometric isomerisation in retinal, strategies to manipulate 2D space by both geometric and positional isomerisation of alkenes via chemical, thermal and light‐driven processes are being intensively pursued. This minireview highlights the current state of the art in activating and achieving directionality in these fundamental chemical transformations. 相似文献
235.
The carbon‐carbon and carbon‐heteroatom bond formation reactions are considered as a fundamental tool in synthetic organic chemistry. They have been effectively utilized in the synthesis of medicinally significant molecules, agrochemicals and valuable compounds in material sciences. This has been primarily enabled by highly efficient protocols arising from divergent mechanistic pathways. In this personal account, we aim to discuss some recent advances in carbon‐carbon or carbon‐heteroatom bond formation reactions to which our group has actively contributed. More specifically, this record focuses on the use of unsaturated carbon compounds for the construction of C?C and C?X bonds. 相似文献
236.
237.
A number of 1,3,1′,3′‐tetrasubstituted bisadamantylidenes are examined with 4 different density functional methods (BP86‐D3, ωB97X‐D, B3LYP, and B3LYP‐D3) and the 6‐311G(d) basis set. With increasing steric bulk, these substituted bisadamantylidenes become ever more twisted about the central carbon‐carbon double bond. This manifests in significantly reduced singlet‐triplet gaps from that of typical alkenes, with the tetra‐t‐butylbisadamantylidene 17 , twisted to almost 90°, having a gap of only 2.2 kcal mol?1. While its large strain energy may preclude the synthesis of 17 , other less‐strained tetrasubstituted analogues are more feasible synthetic targets and still possess small singlet‐triplet gaps, which should be testable by variable temperature NMR and EPR spectroscopy. The twisted alkenes also result in a low rotational energy barrier, and 4 examples with a low barrier to cis‐trans isomerization are presented. These too should be testable by experiment. 相似文献
238.
Motivated with the continued demand for developing quality material showing better response for the efficient removal of organo‐amphiphilic toxicants, we have demonstrated the growth of three‐dimensional polymer organic framework—a covalent crosslinked polymer C2B derived via photon triggered thiol‐alkene click reaction. Instrumentation techniques such as nuclear magnetic resonance, thermogravimetric analysis, and fourier transform infrared spectroscopy were used for the characterization. FESEM and Cryo‐SEM analysis were done to analyze the morphology of the resin. The adsorption and release experiments were done with ultraviolet‐visible spectroscopic technique. The polymer C2B derived from polyolefin and tetrathiol via thiol‐alkene photoclick reaction showed efficiency toward adsorption of organo‐amphiphilic contaminants such as dioxane, dimethylformamide, fluorescein, and rhodamine B (RH). Even the material selectively showed the efficient release of toxicant—RH. Moreover, it can be reused over cycles. This makes the polymer C2B as potential candidate to be commercially viable for textile industries. 相似文献
239.
Zi-Qi Li Yue Fu Ruohan Deng Van T. Tran Dr. Yang Gao Prof. Peng Liu Prof. Keary M. Engle 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(51):23506-23512
A nickel-catalyzed regiodivergent hydroarylation and hydroalkenylation of unactivated alkenyl carboxylic acids is reported, whereby the ligand environment around the metal center dictates the regiochemical outcome. Markovnikov hydrofunctionalization products are obtained under mild ligand-free conditions, with up to 99 % yield and >20:1 selectivity. Alternatively, anti-Markovnikov products can be accessed with a novel 4,4-disubstituted Pyrox ligand in excellent yield and >20:1 selectivity. Both electronic and steric effects on the ligand contribute to the high yield and selectivity. Mechanistic studies suggest a change in the turnover-limiting and selectivity-determining step induced by the optimal ligand. DFT calculations reveal that in the anti-Markovnikov pathway, repulsion between the ligand and the alkyl group is minimized (by virtue of it being 1° versus 2°) in the rate- and regioselectivity-determining transmetalation transition state. 相似文献
240.