625-65-0Relevant articles and documents
Kinetics of the thermal isomerization of 1,1,2,2-tetramethylcyclopropane
Lewis, David K.,Gray, Timothy,Katsva, Vlad,Parcella, Kyle,Schlier, Jessica,Kalra, Bansi L.,Cho, Janet,Mish, Debra
, p. 483 - 488 (2006)
Reaction rates for the structural isomerization of 1,1,2,2- tetramethylcyclopropane to 2,4-dimethyl-2-pentene have been measured over a wide temperature range, 672-750 K in a static reactor and 1000-1120 K in a single-pulse shock tube. The combined data from the two temperature regions give Arrhenius parameters Ea = 64.7 (±0.5) kcal/mol and log 10(A, s-1) = 15.47 (±0.13). These values lie at the upper end of the ranges of Ea and log A values (62.2-64.7 kcal/mol and 14.82-15.55. respectively) obtained from three previous experimental studies, each of which covered a narrower temperature range. The previously noted trend toward lower Ed values for structural isomerization of methylcyclopropanes as methyl substitution increases extends only through the dimethylcyclopropanes (1,1- and 1,2-); Ea then appears to increase with further methyl substitution. In contrast, the pre-exponential factors for isomerization of cyclopropane and all of the methylcyclopropanes through tetramethylcyclopropane lie within ±0.3 of log10(A,s -1) = 15.2 and show no particular trend with increasing substitution.
Decarbonylative Olefination of Aldehydes to Alkenes
Ainembabazi, Diana,Reid, Christopher,Chen, Amanda,An, Nan,Kostal, Jakub,Voutchkova-Kostal, Adelina
supporting information, p. 696 - 699 (2020/01/31)
New atom-economical alternatives to Wittig chemistry are needed to construct olefins from carbonyl compounds, but none have been developed to-date. Here we report an atom-economical olefination of carbonyls via aldol-decarbonylative coupling of aldehydes using robust and recyclable supported Pd catalysts, producing only CO and H2O as waste. The reaction affords homocoupling of aliphatic aldehydes, as well as heterocoupling of aliphatic and aromatic ones. Computations provide insight into the selectivity and thermodynamics of the reaction. The tandem aldol-decarbonylation reaction opens the door to exploration of new carbonyl reactivity to construct olefins.
Alkanethiolate-capped palladium nanoparticles for selective catalytic hydrogenation of dienes and trienes
Chen, Ting-An,Shon, Young-Seok
, p. 4823 - 4829 (2017/10/19)
Selective hydrogenation of dienes and trienes is an important process in the pharmaceutical and chemical industries. Our group previously reported that the thiosulfate protocol using a sodium S-alkylthiosulfate ligand could generate catalytically active Pd nanoparticles (PdNP) capped with a lower density of alkanethiolate ligands. This homogeneously soluble PdNP catalyst offers several advantages such as little contamination via Pd leaching and easy separation and recycling. In addition, the high activity of PdNP allows the reactions to be completed under mild conditions, at room temperature and atmospheric pressure. Herein, a PdNP catalyst capped with octanethiolate ligands (C8 PdNP) is investigated for the selective hydrogenation of conjugated dienes into monoenes. The strong influence of the thiolate ligands on the chemical and electronic properties of the Pd surface is confirmed by mechanistic studies and highly selective catalysis results. The studies also suggest two major routes for the conjugated diene hydrogenation: the 1,2-addition and 1,4-addition of hydrogen. The selectivity between two mono-hydrogenation products is controlled by the steric interaction of substrates and the thermodynamic stability of products. The catalytic hydrogenation of trienes also results in the almost quantitative formation of mono-hydrogenation products, the isolated dienes, from both ocimene and myrcene.
High yield of liquid range olefins obtained by converting i-propanol over zeolite H-ZSM-5
Mentzel, Uffe V.,Shunmugavel, Saravanamurugan,Hruby, Sarah L.,Christensen, Claus H.,Holm, Martin S.
experimental part, p. 17009 - 17013 (2010/03/23)
Methanol, ethanol, and i-propanol were converted under methanol-to-gasoline (MTH)-like conditions (400°C, 1-20 bar) over zeolite H-ZSM-5. For methanol and ethanol, the catalyst lifetimes and conversion capacities are comparable, but when i-propanol is use
