25068-26-2Relevant articles and documents
Redirection of oxidation reactions by a polyoxomolybdate: Oxydehydrogenation instead of oxygenation of alkanes with tert-butylhydroperoxide in acetic acid
Khenkin,Neumann
, p. 6437 - 6438 (2001)
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Onsager et al.
, p. 187 (1969)
Dispersion of nanosized ceria-terbia solid solutions over silica surface: Evaluation of structural characteristics and catalytic activity
Miah, Abu Taleb,Saikia, Pranjal
, p. 96 - 104 (2018)
In this work, we investigated the dispersion effects of nanosized ceria-terbia solid solutions over silica surface in terms of structural characteristics and catalytic activity. The dispersion process was carried out via a soft chemical route using colloidal silica precursor and nitrate precursors of cerium and terbium. The structural features were elucidated by means of analytical techniques namely TGA, BET surface area, XRD, Raman Spectroscopy, UV-vis DRS, TEM, XPS, and TPR-TPO. The catalyst samples were subjected to thermal treatments at different temperatures ranging from 773 to 1073 K to understand the influence of silica support on dispersion, textural properties, and thermal stability. Catalytic activity was evaluated for selective dehydration of 4-methylpentan-2-ol to 4-methylpent-1-ene in the vapor phase at atmospheric pressure. The silica supported ceria-terbia catalyst exhibited better dehydration activity as well as selectivity in comparison to the unsupported catalyst. The catalytic properties were found to be dependent on structural features of the prepared catalyst samples.
4-BROMO-3,3-DIMETHYL-1-BUTENE: A NEW PROBE FOR RADICAL INTERMEDIATES IN REACTIONS IN STRONGLY BASIC MEDIA
Newcomb, Martin,Williams, William G.,Crumpacker, Elizabeth L.
, p. 1183 - 1184 (1985)
The preparation, isolation and purification of the title bromide (1) are described, and the application of 1 as a mechanistic probe is demonstrated in the metal-halogen interchange reaction with tert-butyllithium.
Rate Constants and Arrhenius Functions for Rearrangements of the 2,3-Dimethyl-3-butenyl and (2,2-Dimethylcyclopropyl)methyl Radicals
Newcomb, Martin,Glenn, Anne G.,Williams, William G.
, p. 2675 - 2681 (1989)
Rate constants for the rearangement of the 2,2-dimethyl-3-butenyl radical (1) to the 1,1-dimethyl-3-butenyl radical (3) via the intermediate (2,2-dimethylcyclopropyl)methyl radical (2) were measured over the temperature range 74 to -78 deg C by the competition method using the reaction of radical 1 with Bu3SnH as the basis reaction.Rate constants for ring opening of radical 2 to both 1 and 3 were measured over the temperature range 50 to -78 deg C by competition against reaction of 2 with PhSH.Arrhenius functions for the 1 to 3, 1 to 2, 2 to 1, and 2 to 3 conversions were calculated; at 25 deg C, the rate constants for these conversions are 4.8*106, 5.6*106, 1.2*108, and 7.7*108 s-1, respectively.At room temperature, cyclization of gem-dimethyl-substituted radical 1 is accelerated by about 3 orders of magnitude over its parent, 3-butenyl radical.Ring opening of 2 is about 1 order of magnitude faster than ring opening of its parent, cyclopropylcarbinyl radical.For the 1 to 2 conversion, K12 varies from 0.05 at 25 deg C to 0.02 at -78 deg C, ΔH12 is 1.0 kcal/mol, ΔS12 is -2.7 eu, and ΔG12 at 25 deg C is 1.8 kcal/mol.
N-Hydroxypyridine-2-thione Esters as Radical Precusors in Kinetic Studies. Measurements of Rate Constants for Hydrogen Atom Abstraction Reactions
Newcomb, Martin,Un Park, Seung
, p. 4132 - 4134 (1986)
N-hydroxypyridine-2-thione esters were employed as radical precursors in kinetic studies.Radical chain reactions of the precursor esters gave 2,2-dimethyl-3-butenyl and 5-hexenyl.These radicals either were trapped by H-atom donors or rearranged, and the rate constants for trapping were determined from the known rate constants for rearrangement and measured product yields.For hydrogen atom donors that reacted too slowly to trap radicals before rearrangement, an estimate of the rate constants for hydrogen atom transfer was made from the yields of rearranged hydrocarbon and alkyl pyridyl sulfide (formed by scavenging of the alkyl radical by the precursor ester).The methods work for a variety of H-atom donors, including thiols, stannanes, phosphines, silanes, and reactive hydrocarbons.The rate constants determined for reduction of alkyl radicals by dicyclohexylphosphine, 1,4-cyclohexadiene, and THF are important for mechanistic studies of potential electron-transfer processes in ractions of nukleophiles with alkyl halides.
METHOD OF PRODUCING TERMINAL DOUBLE BOND-CONTAINING COMPOUND
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Paragraph 0044-0048, (2020/10/09)
SOLUTION: A method of producing a terminal double bond-containing compound includes: reacting a compound represented by the following general formula (I) under a pressure of 0 MPa-G or lower in the presence of a metal oxide catalyst to produce a terminal double bond-containing compound represented by the following general formula (II). In formula (I) and formula (II), R1 and R2 represent hydrocarbon groups, and R1 and R2 may bond each other to form a ring together with carbon atoms by which R1 and R2 bond. EFFECT: According to the present invention, a terminal double bond-containing compound can be safely and easily produced with high selectivity. SELECTED DRAWING: None COPYRIGHT: (C)2020,JPOandINPIT
Synthesis, structure and reactivity of some chiral benzylthio alcohols, 1,3-oxathiolanes and their S-oxides
Aitken, R. Alan,Lightfoot, Philip,Thomas, Andrew W.
, p. 369 - 387 (2020/05/25)
A series of amino acid-derived chiral benzylthio alcohols have been prepared and characterized. A chiral mercapto alcohol derived from S-leucine has been used to form three chiral 2,4-disubstituted 1,3-oxathiolanes. One of these has been oxidized to the S-oxide and another to the S,S-dioxide. The cis and trans isomers have been characterized by 1H NMR in each case and it appears that thermal epimerisation at C-2 is possible at the sulfoxide oxidation state. The X-ray structure of major trans diastereomer of 2-phenyl-4-isobutyl-1,3-oxathiolane S,S-dioxide shows an envelope conformation with oxygen at the flap and an internal angle at sulfur of just 93.8°. This compound fragments upon flash vacuum pyrolysis at 700°C to give SO2, benzaldehyde and 4-methylpent-1-ene.
