544-10-5Relevant articles and documents
EXCHANGE REACTION IN TWO-PHASE CATALYTIC SYSTEMS. 3. KINETICS OF NUCLEOPHILIC SUBSTITUTION IN THE PRESENCE OF A SOLID IONOPHORE
Esikova, I. A.,Yufit, S. S.
, p. 1342 - 1346 (1988)
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Chemo- And regioselective hydroformylation of alkenes with CO2/H2over a bifunctional catalyst
Hua, Kaimin,Liu, Xiaofang,Wei, Baiyin,Shao, Zilong,Deng, Yuchao,Zhong, Liangshu,Wang, Hui,Sun, Yuhan
supporting information, p. 8040 - 8046 (2021/11/01)
As is well known, CO2 is an attractive renewable C1 resource and H2 is a cheap and clean reductant. Combining CO2 and H2 to prepare building blocks for high-value-added products is an attractive yet challenging topic in green chemistry. A general and selective rhodium-catalyzed hydroformylation of alkenes using CO2/H2 as a syngas surrogate is described here. With this protocol, the desired aldehydes can be obtained in up to 97% yield with 93/7 regioselectivity under mild reaction conditions (25 bar and 80 °C). The key to success is the use of a bifunctional Rh/PTA catalyst (PTA: 1,3,5-triaza-7-phosphaadamantane), which facilitates both CO2 hydrogenation and hydroformylation. Notably, monodentate PTA exhibited better activity and regioselectivity than common bidentate ligands, which might be ascribed to its built-in basic site and tris-chelated mode. Mechanistic studies indicate that the transformation proceeds through cascade steps, involving free HCOOH production through CO2 hydrogenation, fast release of CO, and rhodium-catalyzed conventional hydroformylation. Moreover, the unconventional hydroformylation pathway, in which HCOOAc acts as a direct C1 source, has also been proved to be feasible with superior regioselectivity to that of the CO pathway.
Practical and Selective sp3 C?H Bond Chlorination via Aminium Radicals
McMillan, Alastair J.,Sieńkowska, Martyna,Di Lorenzo, Piero,Gransbury, Gemma K.,Chilton, Nicholas F.,Salamone, Michela,Ruffoni, Alessandro,Bietti, Massimo,Leonori, Daniele
supporting information, p. 7132 - 7139 (2021/03/03)
The introduction of chlorine atoms into organic molecules is fundamental to the manufacture of industrial chemicals, the elaboration of advanced synthetic intermediates and also the fine-tuning of physicochemical and biological properties of drugs, agrochemicals and polymers. We report here a general and practical photochemical strategy enabling the site-selective chlorination of sp3 C?H bonds. This process exploits the ability of protonated N-chloroamines to serve as aminium radical precursors and also radical chlorinating agents. Upon photochemical initiation, an efficient radical-chain propagation is established allowing the functionalization of a broad range of substrates due to the large number of compatible functionalities. The ability to synergistically maximize both polar and steric effects in the H-atom transfer transition state through appropriate selection of the aminium radical has provided the highest known selectivity in radical sp3 C?H chlorination.
Supported palladium membrane reactor architecture for electrocatalytic hydrogenation
Delima, Roxanna S.,Sherbo, Rebecca S.,Dvorak, David J.,Kurimoto, Aiko,Berlinguette, Curtis P.
, p. 26586 - 26595 (2019/12/04)
Electrolytic palladium membrane reactors offer a means to perform hydrogenation chemistry utilizing electrolytically produced hydrogen derived from water instead of hydrogen gas. While previous embodiments of these reactors employed thick (≥25 μm) palladium foil membranes, we report here that the amount of palladium can be reduced by depositing a thin (1-2 μm) layer of palladium onto a porous polytetrafluoroethylene (PTFE) support. The supported palladium membrane can be designed to ensure the fast diffusion of reagent and hydrogen to the palladium layer. The hydrogenation of 1-hexyne, for example, shows that the supported Pd/PTFE membrane can achieve reaction rates (e.g., 0.71 mmol h-1) which are comparable to 0.92 mmol h-1 measured for palladium membranes with a high-surface area palladium electrocatalyst layer. The root cause of these comparable rates is that the high porosity of PTFE enables a 12-fold increase in electrocatalytic surface area compared to planar palladium foil membranes. These results provide a pathway for designing a cost-effective and potentially scalable electrolytic palladium membrane reactor.