100-80-1Relevant articles and documents
Excellent Selectivity with High Conversion in the Semihydrogenation of Alkynes using Palladium-Based Bimetallic Catalysts
Liu, Jian,Zhu, Yanan,Liu, Chang,Wang, Xiaoshi,Cao, Changyan,Song, Weiguo
, p. 4053 - 4057 (2017)
A series of active-carbon-supported PdPb and PdCu bimetal catalysts were prepared for the selective semihydrogenation of alkynes in the liquid phase. The Pd0.33Pb0.67/C catalyst showed the best performance for various alkynes under mild reaction conditions (room temperature and ambient H2 pressure) and achieved 100 % conversion with 98 % selectivity to alkenes. In particular, over-hydrogenation was avoided at complete alkyne conversion.
Atomically Dispersed Ruthenium Species Inside Metal–Organic Frameworks: Combining the High Activity of Atomic Sites and the Molecular Sieving Effect of MOFs
Ji, Shufang,Chen, Yuanjun,Zhao, Shu,Chen, Wenxing,Shi, Lijun,Wang, Yu,Dong, Juncai,Li, Zhi,Li, Fuwei,Chen, Chen,Peng, Qing,Li, Jun,Wang, Dingsheng,Li, Yadong
, p. 4271 - 4275 (2019)
Incorporating atomically dispersed metal species into functionalized metal–organic frameworks (MOFs) can integrate their respective merits for catalysis. A cage-controlled encapsulation and reduction strategy is used to fabricate single Ru atoms and triatomic Ru3 clusters anchored on ZIF-8 (Ru1@ZIF-8, Ru3@ZIF-8). The highly efficient and selective catalysis for semi-hydrogenation of alkyne is observed. The excellent activity derives from high atom-efficiency of atomically dispersed Ru active sites and hydrogen enrichment by the ZIF-8 shell. Meanwhile, ZIF-8 shell serves as a novel molecular sieve for olefins to achieve absolute regioselectivity of catalyzing terminal alkynes but not internal alkynes. Moreover, the size-dependent performance between Ru3@ZIF-8 and Ru1@ZIF-8 is detected in experiment and understood by quantum-chemical calculations, demonstrating a new and promising approach to optimize catalysts by controlling the number of atoms.
Homogeneous Unimolecular Pyrolysis Kinetics of o-, m-, and p-Methyl-2-phenylethyl Chlorides
Chuchani, Gabriel,Medina, Jose D.,Martin, Ignacio,Hernandez A, Jose A.
, p. 3900 - 3902 (1981)
The pyrolysis kinetics of isomeric methyl-2-phenylethyl chlorides have been studied in a static system over the pressure range of 56-240 torr and the temperature range of 419-470 deg C.These eliminations in seasoned vessels and in the presence of propene inhibitor are homogeneous and unimolecular, and follow a first-order rate law.The rate coefficients are given by the following Arrhenius equations: for 0-methyl-2-phenylethyl chloride, log k1 (s-1)=13.76+/-0.27)-(231.4+/-3.6) kJ mol-1 (2.303RT)-1; for m-methyl-2-phenylethyl chloride, log k1(s-1)=12.84+/-0.26)-(219.2+/-3.5) kJ mol-1 (2.303RT)-1; for p-methyl-2-phenylethyl chloride, log k1 (s-1)=(14.03+/-0.19)-(234.1+/-2.5) kJ mol-1 (2.303RT)-1.The electron release of the methyl substituent, at the three isomeric positions of the benzene ring, is very weak and does not reinforce the phenyl participation in rate enchancement relative to 2-phenylethyl chloride.
Tandem Diazotization Heck Reactions: A General Synthesis of Substituted Styrenes from Anilines
Beller, Matthias,Fischer, Hartmut,Kuehlein, Klaus
, p. 8773 - 8776 (1994)
The palladium-catalyzed olefination of different anilines with ethylene is shown to proceed generally in good yields.The substituted styrenes were obtained highly selective in a direct tandem diazotization Heck reaction at room temperature under atmospheric pressure of ethylene without concomitant side reaction to stilbenes.
Phenylacetylene semihydrogenation over a palladium pyrazolate hydrogen-bonded network
Augustyniak, Adam W.,Trzeciak, Anna M.
, (2021)
The palladium azolate/carboxylate network (Pd-dmpzc) catalyses the selective hydrogenation of phenylacetylene to styrene in water. Under optimised conditions, at a Pd:NaBH4 ratio of 1:100 at 40 °C, Pd-dmpzc provided much better results than Pd(OAc)2 or PdCl2(CH3CN)2. Analysis of the recovered catalyst revealed the presence of different Pd2+ species and Pd0 NPs which contributed in the catalytic reaction.
Selective transfer semihydrogenation of alkynes with nanoporous gold catalysts
Wagh, Yogesh S.,Asao, Naoki
, p. 847 - 851 (2015)
A facile, highly chemo- and stereoselective transfer semihydrogenation of alkynes to Z-olefins has been achieved by use of unsupported nanoporous gold (AuNPore) as a heterogeneous catalyst together with formic acid as a hydrogen donor. A variety of terminal/internal and aromatic/aliphatic alkynes were reduced to the corresponding alkenes in high chemical yields with good functional-group tolerance. The catalyst is robust enough to be reused without leaching.
A Metal-Free Oxidative Dehydrogenative Diels–Alder Reaction for Selective Functionalization of Alkylbenzenes
Manna, Srimanta,Antonchick, Andrey P.
, p. 7825 - 7829 (2017)
Functionalization of C(sp3)?H bonds under metal-free reaction conditions is a great challenge due to poor bond reactivity. A novel metal-free oxidative dehydrogenative Diels–Alder reaction of alkylbenzene derivatives with alkenes through C(sp3)?H bond functionalization is described. The developed oxidative method provides a straightforward approach to biologically relevant 1,4-phenanthraquinone and isoindole derivatives from readily available starting materials. Furthermore, the synthesis of nitrostyrenes from enylbenzene derivatives by selective C(sp3)?H bond functionalization has been demonstrated.
Controlling the Lewis Acidity and Polymerizing Effectively Prevent Frustrated Lewis Pairs from Deactivation in the Hydrogenation of Terminal Alkynes
Geng, Jiao,Hu, Xingbang,Liu, Qiang,Wu, Youting,Yang, Liu,Yao, Chenfei
, p. 3685 - 3690 (2021)
Two strategies were reported to prevent the deactivation of Frustrated Lewis pairs (FLPs) in the hydrogenation of terminal alkynes: reducing the Lewis acidity and polymerizing the Lewis acid. A polymeric Lewis acid (P-BPh3) with high stability was designed and synthesized. Excellent conversion (up to 99%) and selectivity can be achieved in the hydrogenation of terminal alkynes catalyzed by P-BPh3. This catalytic system works quite well for different substrates. In addition, the P-BPh3 can be easily recycled.
Photoredox Catalyzed Sulfonylation of Multisubstituted Allenes with Ru(bpy)3Cl2 or Rhodamine B
Chen, Jingyun,Chen, Shufang,Jiang, Jun,Lu, Qianqian,Shi, Liyang,Xu, Zekun,Yimei, Zhao
supporting information, (2021/11/09)
A highly regio- and stereoselective sulfonylation of allenes was developed that provided direct access to α, β-substituted unsaturated sulfone. By means of visible-light photoredox catalysis, the free radicals produced by p-toluenesulfonic acid reacted with multisubstituted allenes to obtain Markovnikov-type vinyl sulfones with Ru(bpy)3Cl2 or Rhodamine B as photocatalyst. The yield of this reaction could reach up to 91%. A series of unsaturated sulfones would be used for further transformation to some valuable compounds.
Polymerization of Allenes by Using an Iron(II) β-Diketiminate Pre-Catalyst to Generate High Mn Polymers
Durand, Derek J.,Webster, Ruth L.,Woof, Callum R.
supporting information, p. 12335 - 12340 (2021/07/19)
Herein, we report an iron(II)-catalyzed polymerization of arylallenes. This reaction proceeds rapidly at room temperature in the presence of a hydride co-catalyst to generate polymers of weight up to Mn=189 000 Da. We have determined the polymer structure and chain length for a range of monomers through a combination of NMR, differential scanning calorimetry (DSC) and gel permeation chromatography (GPC) analysis. Mechanistically, we postulate that the co-catalyst does not react to form an iron(II) hydride in situ, but instead the chain growth is proceeding via a reactive Fe(III) species. We have also performed kinetic and isotopic experiments to further our understanding. The formation of a highly unusual 1,3-substituted cyclobutane side-product is also investigated.
