19901-15-6Relevant articles and documents
Heptakis-6-amino-6-deoxy-β-cyclodextrin as a catalyst for H/D exchange
Binder, Wolfgang H.,Menger, Fredric M.
, p. 8963 - 8966 (1996)
Heptakis-6-amino-6-deoxy-β-cyclodextrin 2 at pD = 6.50, 20°C catalyzes CH/CD exchange in malonic acid, pyruvic acid and acetaldehyde. Accelerations as large as 3800 were observed. Copyright (C) 1996 Elsevier Science Ltd.
Selective oxidation of ethanol to acetaldehyde on gold
Gong, Jinlong,Mullins, C. Buddie
, p. 16458 - 16459 (2008)
We present results from an investigation of the oxidative conversion of ethanol into acetaldehyde on Au(111) employing temperature-programmed desorption (TPD) and molecular beam reactive scattering (MBRS). Results from isotopic experiments show that ethan
Investigation of the Mechanism of Photocatalytic Alcohol Dehydrogenation over Pt/TiO2 using Poisons and Labelled Ethanol
Pichat, Pierre,Mozzanega, Marie-Noelle,Courbon, Henri
, p. 697 - 704 (1987)
Poisoning experiments using pyridine, piperidine, aqueous ammonia, phenol and 2-nitrophenol show that both acid and base sites are involved in the room-temperature photocatalytic dehydrogenation of alcohols (liquid propan-1-ol being chosen for the tests)
Nickel-Mediated Stepwise Transformation of CO to Acetaldehyde and Ethanol
Zhang, Ailing,Raje, Sakthi,Liu, Jianguo,Li, Xiaoyan,Angamuthu, Raja,Tung, Chen-Ho,Wang, Wenguang
, p. 3135 - 3141 (2017/09/05)
The insertion of CO into the Ni-C bond of synthetic Ni(II)-CH3 cationic complex ([1-CH3]+) affords a nickel-acetyl complex ([1-COCH3]+). Reduction of resultant [1-COCH3]+ by borohydrides produces CH3CHO, CH3CH2OH, and an Ni(0) compound ([1]0), which can react with CH3I to regenerate [1-CH3]+. By conducting deuterium labeling experiments, we have demonstrated that CH3CHO is the primary product from CH3CH2OH in such CO transformation reactions. In the reduction of [1-COCH3]+, the formation of CH3CHO competes with the loss of CH4, which leads to a Ni(0)-CO compound ([1-CO]0) as a minor product. Our results establish fundamental steps in the exploration of nickel-mediated CO transformation to valuable chemicals.
Are Tetrahedral Intermediates Formed by Addition of Nucleophiles to Organoboranes in the Gas Phase?
Currie, Graeme J.,Bowie, John H.,Downard, Kevin M.,Sheldon, John C.
, p. 1973 - 1980 (2007/10/02)
Nucleophilic addition of CD3O- to Me2BOMe gives the same addition product as the corresponding reaction between Me2BOCD3 and MeO-, as evidenced by the identical collisional activation mass spectra of the products.This is interpreted in terms of exclusive formation of a boron product ion of terahedral geometry.The decompositions of the product involve loss of MeOH and CD3OH and the formation of MeO- and CD3O-.The major decompositions of (CD3)3B+-OCH2CH2XMe (X=O, S, or NMe2) are similar to those outlined above and may be explained by initial formation of (CD3)3B-OCH2CH2XMe.However, there are some unusual fragmentations (e.g. loss of CH3D) which may occur through the alternative structure (CD3)3B-X+(Me)CH2CH2O-.It is suggested the other ambident species may also react with Me3B to form several tetrahedral species, e.g. deprotonated methyl acetate could yield Me3B-CH2CO2Me, Me3B-OC(OMe)=CH2, and Me3B--O+(Me)CCH2O-.The formation of the third structure is supported by the pronounced loss of ketene from this system.
Fermi resonance structure in the CH vibrational overtones of CD3CHO
Amrein, A.,Hollenstein, H.,Quack, M.,Zenobi, R.,Segall, J.,Zare, R. N.
, p. 3944 - 3951 (2007/10/02)
Gas-phase fundamental and CH and CO overtone spectra (700-17 500 cm-1) of 2,2,2- trideuteroacetaldehyde were recorded using FTIR and laser photoacoustic techniques.The Fermi resonance structure in the overtone spectra of the coupled CH stretching and in-plane CH bending vibrations is analy zed with a tridiagonal Hamiltonian yielding a large effective coupling constant, =93 cm-1, corresponding to subpicosecond redistribution times.No coupling between the out- of plane CH bending mode and the Fermi resonance system is apparent.This study presents the first detailed analysis of the anharmonic couplings in the CH chromophore at an sp2 carbon atom.The in- plane CH bending vibration couples in a manner similar to the CH ( sp3 ) bending vibrations, whereas the out-of plane bending vibration is decoupled, similar to the CH(sp) bending vibrations.
Oxidation of (CD3)2C.X Radicals. I. Reaction of Propane and Isopropyl Radicals with Atomic Oxygen
Washida, Nobuaki
, p. 3739 - 3750 (2007/10/02)
The raection of oxygen atoms with propane-1,1,1,3,3,3-d6, (CD3)CH2, in a fast-flow system was studied with a photoionization mass spectrometer.Isopropyl-d6 radicals, (CD3)2CH, formed by the initial hydrogen abstraction at the 2-position were detected directly. The subsequent reaction of (CD3)2C.H radicals with atomic oxygen proceeds by both an deuterium abstraction (61percent) and an oxygen addition reaction (39percent).The product in the deuterium abstraction was CD2CHCD3 and those in the oxygen addition were (CD3)2CO (18percent) and CD3CHO (21percent). Competitition experiments show that (CD3)2C.H radicals react (0.029 +/- 0.004) times as fas with O2 as with O(3P).In the presence of an excess of O2, CD2CHCD3 was observed in decreased yield (20percent) and (CD3)2CO and CD3CHO increased to 32 and 44percent, respectively.The rate data for Reaction 3 were fitted by an Arrhenius expression: k3=(2.0+1.0-0.7)*10-10 exp-1)/RT> cm3 molecule-1 s-1 (381-627 K).The rate constant of Reaction 3 obtained from the yields of products was 7.9*10-15 cm3 molecule-1 s-1 at 298 K.
A Correlation between β-Hydrogen Isotope Effects on Carbon-13 NMR Chemical Shifts in Unsaturated Systems and the Strength of Hyperconjugative Interactions
Arrowsmith, Cheryl H.,Kresge, A. Jerry
, p. 7918 - 7920 (2007/10/02)
β-Hydrogen isotope effects on the carbon-13 NMR chemical shifts of the trigonal carbon in CL3C(R)=X (L=H, or D) are reported for 15 substances inwhich the positive charge density at the trigonal carbon is regulated through systematic variation of R and X.A linear relationship is found between these isotope effects and the chemical shifts of the trigonal carbons, and this is taken as evidence for dependence of the magnitude of these isotope effects upon the strength of the hyperconjugative interaction between CL3 and C(R)=X.An explanation of hyperconjugative NMR isotope effecs in terms of anharmonic carbon-hydrogen bond-bending vibrations is advanced.
INTERMEDIATES IN COBALT-CATALYSED METHANOL HOMOLOGATION: LABELLING STUDIES WITH DEUTERATED METHANOL AND METHYL IODIDE
Roeper, Michael,Loevenich, Heinz
, p. 95 - 102 (2007/10/02)
The cobalt-catalysed homologation of perdeuterated methanol with CO/H2 gives C2 products in which the CD3 group remains intact.GC/MS measurements showed that no H/D exchange unless the methanol conversion exceeded 50percent.These results indicate that methylene species are unlikely to be as catalytic intermediates, and favour methyl species for such intermediates.In the presence of iodine promoters methyl iodide is a likely intermediate since it is much more readily consumed than methanol in carbonylation/hydrocarbonylation reactions.This was shown by treating a 5/1 mixture of CH3OH and CD3I with CO/H2 in the presence of Co2(CO)8; at short reaction times only the carbonylation/hydrocarbonylation products of methyl iodide could be detected by GC/MS.Methyl iodide can be formed from variety of iodine compounds under homologation conditions, as was confirmed by separate experiments.
