1112-54-5Relevant articles and documents
Additive-free Semihydrogenation of an Alkynyl Group to an Alkenyl Group over Pd?TiO2 Photocatalyst Utilizing Temporary In-situ Deactivation
Kojima, Yasumi,Fukui, Makoto,Tanaka, Atsuhiro,Hashimoto, Keiji,Kominami, Hiroshi
, p. 3605 - 3611 (2018)
Lindlar's catalyst, i. e., calcium carbonate-supported palladium (Pd) modified with lead, has been used for semihydrogenation of an alkynyl group in the presence of hydrogen gas (H2). We examined hydrogenation of an alkynyl group in organosilane and hydrocarbon in methanolic suspensions of a Pd-loaded titanium(IV) oxide (Pd?TiO2) photocatalyst without the use of additives and H2. In the photocatalytic reaction, Pd particles worked as co-catalysts for hydrogenation and alkyne hydrogenation had priority to alkene hydrogenation. Since the Pd co-catalyst was temporarily deactivated during the reaction owing to accumulation of the oxidized product(s) of methanol, the capacity of hydrogenation of the unsaturated C?C bond was limited. By optimizing the capacity and amount of alkynes, almost complete semihydrogenation of alkynes was achieved under a poison-free condition. Pd?TiO2 can be regenerated by very simple treatments, i. e., washing and drying at room temperature.
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Seyferth,Weiner
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Hayakawa et al.
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Ruthenium-Catalyzed Coupling Reactions of CO2 with C2H4 and Hydrosilanes towards Silyl Esters
Kunihiro, Kana,Heyte, Svetlana,Paul, Sébastien,Roisnel, Thierry,Carpentier, Jean-Fran?ois,Kirillov, Evgueni
supporting information, p. 3997 - 4003 (2021/02/01)
A series of in situ-prepared catalytic systems incorporating RuII precursors and bidentate phosphine ligands has been probed in the reductive carboxylation of ethylene in the presence of triethylsilane as reductant. The catalytic production of propionate and acrylate silyl esters was evidenced by high-throughput screening (HTS) and implemented in batch reactor techniques. The most promising catalyst systems identified were made of Ru(H)(Cl)(CO)(PPh3)3 and 1,4-bis(dicyclohexylphosphino)butane (DCPB) or 1,1’-ferrocene-diyl-bis(cyclohexylphosphine) (DCPF). A marked influence of water on the acrylate/propionate selectivity was noted. Turnover numbers [mol mol(Ru)?1] up to 16 for acrylate and up to 68 for propionate were reached under relatively mild conditions (20 bar, 100 °C, 0.5 mol % Ru, 40 mol % H2O vs. HSiEt3). Possible mechanisms are discussed.
Catalytic study of heterobimetallic rhodium complexes derived from partially alkylated s-indacene in dehydrogenative silylation of olefins
Adams,Riviere,Riviere-Baudet,Morales-Verdejo,Dahrouch,Morales,Castel,Delpech,Manríquez,Chávez
, p. 266 - 274 (2013/11/19)
This work describes the catalytic study of heterobimetallic rhodium compounds derived from partially alkylated s-indacene in dehydrogenative silylation of olefins in order to elucidate as much as possible the effects of: solvent, temperature, chemical substrates, olefin effect, silane effect, and secondary metallic fragment. The rhodium complexes, anti-[Cp*Fe-s- Ic′-Rh(COD)] 1, anti-[Cp*Ru-s-Ic′-Rh(COD)] 2, and syn-[Cp*Ru-s-Ic′-Rh(COD)] 2′ (with s-Ic′: 2,6-diethyl-4,8-dimethyl-s-indaceneiide) were previously synthesized and characterized, and were compared with the catalytic activity of the complexes previously reported; monometallic [(COD)Rh-s-Ic′H] 3, and homobimetallic anti-[{(COD)Rh}2-s-Ic′] 4, and syn-[{(COD)Rh} 2-s-Ic′] 4′. The heterobimetallic complexes show a high activity and selectivity for the dehydrogenative silylation of styrene and these complexes show also the presence of a cooperative effect between both metallic centers, which is evidenced when compared with monometallic complex.
