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An experimental study of the thermal decomposition of a β‐hydroxy alkene, 3‐methyl‐3‐buten‐1‐ol, in m‐xylene solution, has been carried out at five different temperatures in the range of 513.15–563.15 K. The temperature dependence of the rate constants for the decomposition of this compound in the corresponding Arrhenius equation is given by ln k (s?1) = (25.65 ± 1.52) ? (17,944 ± 814) (kJ·mol?1)·T?1. A computational study has been carried out at the M05–2X/6–31+G(d,p) level of theory to calculate the rate constants and the activation parameters by the classical transition state theory. There is a good agreement between the experimental and calculated rate constants and activation Gibbs energies. The bonding characteristics of reactant, transition state, and products have been investigated by the natural bond orbital analysis, which provides the natural atomic charges and the Wiberg bond indices. Based on the results obtained, the mechanism proposed is a one‐step process proceeding through a six‐membered cyclic transition state, being a concerted and slightly asynchronous process. The results have been compared with those obtained previously by us (Struct Chem 2013, 24, 1811–1816) for the thermal decomposition of 3‐buten‐1‐ol, in m‐xylene solution. We can conclude that in the compound studied in this work, 3‐methyl‐3‐buten‐1‐ol, the effect of substitution at position 3 by a weakly activating CH3 group is the stabilization of the transition state formed in the reaction and therefore a small increase in the rate of thermal decomposition. 相似文献
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Abstract Due to the wide use of polymers in medicine, researchers are required to solve a very important problem–to understand the interaction between materials of nonphysiological origin and the surrounding biological liquids, and tissues, particularly blood. 相似文献
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Dobson KD McQuillan AJ 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2000,56(3):557-565
In situ infrared spectroscopy has been used to investigate the adsorption of a range of simple aromatic carboxylic acids from aqueous solution to metal oxides. Thin films of TiO2, ZrO2, Al2O3 and Ta2O5 were prepared by evaporation of aqueous sols on single reflection ZnSe prisms. Benzoic acid adsorbed very strongly to ZrO2, in a bridging bidentate fashion, but showed only weak adsorption to TiO2 and Ta2O5. Substituted aromatic carboxylic acids; salicylic, phthalic and thiosalicylic, were found to adsorb to each metal oxide. Salicylic and phthalic acids adsorbed to the metal oxides via bidentate interactions, involving coordination through both carboxylate and substituent groups. Thiosalicylic acid adsorbed to the metal oxides as a bridging bidentate carboxylate with no coordination through the thiol substituent group. 相似文献
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We give a planar proof of the fact that if G is a 3-regular graph minimal with respect to having crossing number at least 2, then the crossing number of G is 2. 相似文献
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Dichlorobis(η5-t-butylcyclopentadienyl)titanium(IV), (t-BuCp)2TiCl2, crystallises in space group P21212 (orthorhombic) with a 12.862(14), b 10.709(9), c 6.602(9) Å, Z = 2. The two t-butyl groups are directed away from each other on opposite sides of the molecule; the overall molecular symmetry is C2. The individual titanium-ring carbon atom distances are not all equal, but vary from 2.330(5) to 2.475(4) Å, the distortion from an exactly symmetric conformation being in a direction which increases the separation between the titanium atom and the carbon atom carrying the t-butyl substituent group. 相似文献
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Donald L. McQuillan 《Archiv der Mathematik》1979,33(1):121-126
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