84615-47-4Relevant academic research and scientific papers
Mechanistic Insights into Electroreductive C-C Coupling between CO and Acetaldehyde into Multicarbon Products
Chang, Xiaoxia,Malkani, Arnav,Xu, Bingjun,Yang, Xuan
, p. 2975 - 2983 (2020/03/10)
Production of valuable multicarbon (C3+) products through the electrochemical CO2 and CO reduction reactions (CO2RR and CORR) is desirable; however, mechanistic understanding that enables C-C coupling beyond the self-coupling of CO to valuable products is lacking. In this work, we elucidate the C-C coupling mechanism between CO and acetaldehyde, a reactive intermediate in both CO2RR and CORR, via combined isotopic labeling and in situ spectroscopic investigations. CO attacks the carbonyl carbon of acetaldehyde in the coupling, and the carbon in CO ends up in the hydroxymethyl group (-CH2OH) of the produced 1-propanol. While the coupling between CO and acetaldehyde does occur when the CORR is conducted with added acetaldehyde, only a minor fraction (up to 36%) of 1-propanol is from this pathway, and the majority of it is produced in the CORR by the self-coupling among CO. The adsorbed methylcarbonyl is proposed as the likely intermediate where the reaction pathway bifurcates to C2 and C3 products; i.e., it could either be hydrogenated to acetaldehyde and ethanol or couple with CO leading to the formation of 1-propanol.
Synthesis of [1-11C]propyl and [1-11C]butyl iodide from [11C]carbon monoxide and their use in alkylation reactions
Eriksson, Jonas,Antoni, Gunnar,Langstroem, Bengt
, p. 1105 - 1116 (2007/10/03)
A method to prepare [1-11C]propyl iodide and [1- 11C]butyl iodide from [11C]carbon monoxide via a three step reaction sequence is presented. Palladium mediated formylation of ethene with [11C]carbon monoxide and
Isomerization and Fragmentation of Aliphatic Thioether Radical Cations in the Gas Phase: Ion-Neutral Complexes in the Reactions of Metastable Ethyl Propyl Thioether Ions
Zappey, Herman W.,Ingemann, Steen,Nibbering, Nico M. M.
, p. 1887 - 1892 (2007/10/02)
The dominant unimolecular reactions of the molecular ion of ethyl propyl thioether are (i) loss of a methyl radical from the ethyl or the propyl group, (ii) loss of an ethyl radical from the propyl group and (iii) elimination of a propene molecule and an allyl radical by transfer of one or two hydrogen atoms, respectively, from the propyl group to the sulphur atom.The loss of a methyl radical on the μs timescale involves only the propyl entity and is preceded by an isomerization of this group to an isopropyl group.Partial loss of the positional identity of thehydrogen atoms of the propyl group occurs during the reactions of the metastable ions, but incorporation of hydrogen or carbon atoms from the ethyl group into the formed neutral species does not occur.The reactions of the metastable ions are discussed in terms of cleavage of the C-S bond assisted by a 1,2-hydride shift in the incipient carbenium ion leading to an ion-neutral complex of a thioethoxy radical and a secondary propyl carbenium ion.The ion-neutral complex can recombine to form the molecular ion of ethyl isopropyl thioether prior to methyl radical loss, or react by proton transfer to give a complex of CH3CH2SH+. and CH2=CH-CH3, which may dissociate or undergo hydrogen atom transfer followed by elimination of an allyl radical.The partial loss of positional identity of the hydrogen atoms during the decomposition of the metastable ions is mainly a result of reversible proton transfer between the constituents, which competes favourably with 1,2-hydride shifts within the carbenium ion entity of the complex.
Ion-Neutral Complexes as Intermediates in the Decompositions of C5H10O2.+ Isomers
McAdoo, David J.,Hudson, Charles E.,Skyiepal, Mark,Broido, Ellen,Griffin, Lawrence L.
, p. 7648 - 7653 (2007/10/02)
Ionized pentanoic acid, 3-methylbutanoic acid, and the enol isomer of ionized isopropyl acetate are shown to pass in part through common intermediates before decomposing to CH3C.HC(OH)2+ (7) and the "McLafferty + 1" ion CH3C(OH)2+ (10).The H transfer to form the methyl of CH3C(OH)2+ and the joining of two CH2 groups to form the C-C bond in the ethylene eliminated to produce CH3C.HC(OH)2+ are both attributed to reactions of the ion-neutral complex .H2C(OH)2+>.The McLafferty + 1 ion is also formed, especially from ionized esters, by another pathway in which complexes may or may not be intermediates.The intermediacy of the ion-neutral complexes is supported by energetic considerations, isotope effects, and the decomposition patterns of labeled ions.The latter correlate with a preference for hydrogen transfer from the end carbons of the C3 partner in other reactions proposed to be complex-mediated.Unification of the McLafferty rearrangement, the McLafferty + 1 rearrangement, and the McLafferty rearrangement with charge reversal by a common initial γ-hydrogen rearrangement followed by dissociation or isomerization in ion-neutral complexes is proposed.Group migration by 1,2-shifts, possibly by dissociation to form a double bond in one partner in an ion-neutral complex followed by addition at the opposite end of the double bond, is shown to be a general reaction of ions in the gas phase.
Unimolecular Dissociations of the +. Metastable Ion
Bouchoux, Guy,Tortajada, Jeanine,Dagaut, Jacques,Fillaux, Joelle
, p. 451 - 457 (2007/10/02)
The metastable molecular ion of 2-hexanone loses a methyl radical mainly (ca. 80percent) from positions C(4) and C(6), in equal proportions, as indicated by 13C labelling.The necessary skeletal rearrangement of the butyl chain is interpreted in terms of a 1,2-+. shift .The results and the mechanisms concerning the minor eliminations of C2H4, C2H5., C3H5. and C3H6 neutrals are also discussed.
Pseudo One-Step Cleavage of C-C Bonds in the Decomposition of Ionized Carboxyclic Acids. Radical Like Reactions in Mass Spectrometry
Weiske, Thomas,Schwarz, Helmut
, p. 323 - 347 (2007/10/02)
Metastable molecular ions of hexanoic acid (1) decompose unimolecularly to C2H5. and protonated methacrylic acid (5-H+)(92percent rel. abund.).Investigation of the mechanism reveals that 1) the branched cation radical 11 must be regarded as the essential intermediate in the course of the rearrangement/dissociation reaction and 2) the process commences with intramolecular hydrogen transfer from either C-3 or C-5 to the ionized carbonyl oxygen ("hidden" hydrogen migration).Hydrogen transfer from C-4, which would correspond to the well-known McLafferty rearrangement, is of no importance in the C2H5.-elimination from 1.The same conclusion applies for various alternative mechanisms, as for example a SRi type reaction, 1 -> 2-H+.The gas phase chemistry of the cation radical of 1, and in particular the hydrogen exchange processes between the methylene groups C-2/C-3 and C-5/C-6, is in surprisingly close correspondence to the chemistry of free alkyl radicals. - The syntheses of various 13C and 2H-labelled model compounds are described.
