6552-57-4Relevant academic research and scientific papers
Experimental investigation of the primary and secondary deuterium kinetic isotope effects for epoxidation of alkenes and ethylene with m- chloroperoxybenzoic acid
Koerner, Terry,Slebocka-Tilk,Brown
, p. 196 - 201 (2007/10/03)
The secondary deuterium kinetic isotope effect (DKIE) for the epoxidation of ethylene and d4-ethylene by m-chloroperoxybenzoic acid (MCPBA) is determined to be 0.83, or 0.95/α-H. The second-order rate constants for MCPBA and MCPBA-O-D epoxidation of a variety of alkenes that differ in the steric access to the double bond (anti-sesquinorbornene (2), tetramethylethylene (3), adamantylideneadamantane (4), 7-norbornylidene-7'- norbornane (5), bis(bicyclo[3.3.1.]non-9-ylidene) (6), bis(homoadamantane) (7), cyclohexene (8), 1-octene (9), trans-5-decene (10) and 2-methyl-1- pentene (11)) have been determined in dichloroethane at 25°C using UV kinetics, and the primary DKIE, k(OH)/k(OD), is 1.05 ± 0.05 in all eases. By comparison of the rates of epoxidation of sterically encumbered alkenes, it is suggested that the spiro epoxidation transition state is favored over a planar one. The products of the epoxidation of anti-sesquinorbornene are determined to be the epoxide and a cis-hydroxy ester, the latter most probably being formed by acid-catalyzed ring opening of the epoxide by in situ-produced m-chlorobenzoic acid produced in situ to form a β-hydroxy carbocation and carboxylate ion pair that collapses to product.
Photoinduced Oxygen Transfer from NO2 to Ethylene in the Vicinity of the NO2 Dissociation Threshold. A Laser Photochemical Study on Reactant Pairs Isolated in Solid Argon
Fitzmaurice, Donald J.,Frei, Heinz
, p. 10308 - 10315 (2007/10/02)
The wavelength dependence of the photochemistry of C2H4*NO2 and C2D4*NO2 pairs, isolated in solid Ar, in the range 555-355 nm is reported.Continuos-wave pulsed dye lasers were used to excite the reactants, and the products were monitored by FT infrared sp
Infrared Photodissociation of Hydrogen-Bonded Complexes Trapped in Inert Matrices. The Ethylene Oxide-Hydrogen Iodide System
Bernadet, Philippe,Schriver, Louise,Schriver, Andre,Perchard, Jean-Pierre
, p. 7204 - 7210 (2007/10/02)
Matix isolation infrared spectroscopy applied to the ethylene oxide/H(D)I system trapped in solid Ar and N2 allows identification of several kinds of hydrogen-bonded complexes: a 1:1 species which exists under different structures and larger aggregates giving rise to proton transfer with formation of ionic species of the type + or (IHI)- characterized by quasi-symmetrical single-minimum potential functions for the proton (proton sharing).The interconversion between the hydrogen-bonded (C) and the non-hydrogen-bonded (U) form of the 1:1 complex is seen to depend on two parameters: temperature and infrared irradiation.Kinetic measurements of the disappearance (or appearance) of C have shown that the C->U conversion is mainly induced by IR radiations in the range 1500-2300 cm-1, corresponding to the excitation of νs (HI stretching mode), while the CU conversion rate with DI suggests a barrier greater than 1500 cm1- for this photoprocess.
Infrared Spectrum of the Primary Ozonide of Ethylene in Solid Xenon
Kohlmiller, Christopher K.,Andrews, Lester
, p. 2578 - 2583 (2007/10/02)
Separate Xe/O3 and Xe/C2H4 mixtures were condensed on a CsI window at 50 K and then warmed to 80-100 K.Strong infrared absorption due to the secondary ozonide and weaker bands at 409, 647, 727, 846, 927, 983, and 1214 cm-1 replaced the ethylene and ozone absorptions.The latter new bands agree with earlier solid film and CO2 matrix studies and are assigned to the primary ozonide.Isotopic substitution (16,18O3, 18O3, CH2CD2, C2D4, 13C2H4) provides a sound basis for vibrational assignments.A sextet splitting for the 647-cm-1 antisymmetric O-O-O stretching mode in the 50percent oxygen-18 enriched experiment confirms the primary ozonide structure and directly characterizes the weak O-O-O single bonds.
The Mechanism of the Cationic Cyclooligomerization of Ethylene Oxide and the Concomitant Degradation of the Crown Ether Products Formed
Dale, Johannes,Daasvatn, Kari
, p. 327 - 342 (2007/10/02)
Cyclooligomerization of ethylene oxide-d4 with BF3 in CH2Cl2 in the presence of the higher cyclic oligomers, from 1,4-dioxan-h8 to 18-crown-6-h24, each separately, has been studied as a function of time, analyzing the product composition by gas chromatography, and the distribution of isotopically different species within each ring size by GLC-MS using chemical ionization.It is found that non-deuteriated units from any one of these rings become incorporated in both larger and smaller rings before they end up in dioxan, either alone or together with deuteriated units from ethylene oxide.The particular patterns observed for the degree of deuteriation permit quite far-reaching conclusions as to the detailed mechanism of these reactions, the most important of which is that the transition state for attack by oxygen on an oxonium ion has a strict linear SN2-like geometry.
