Mechanism of Hydrogenolysis. I. Effect of Methyl Substituent on the Demethylation Rate of Polymethylbenzenes
スポンサーリンク
概要
- 論文の詳細を見る
Rates of demethylation of six different polymethylbenzenes have been measured, at 702°C and residence times ranging from 0.5 to 6.0 sec in the presence of five-fold in excess hydrogen, by using toluene as an internal reference. The rates per one equivalent methyl group were: 1.08 for <I>p</I>-xylene, 1.73 for <I>o</I>-xylene, 1.26 for 4-position of 1,2,4-trimethylbenzene, 1.87 for 2-position of 1,2,4-trimethylbenzene, 1.85 for 1-position of 1,2,4-trimethylbenzene, 1.20 for 1,3,5-trimethylbenzene, 2.22 for 1-positionof 1,2,3-trimethylbenzene, 3.25 for 2-position of 1,2,3-trimethylbenzene, 1.5 for 5-position of 1,2,3,5-tetramethylbenzene, 2.1 for 1-position of 1,2,3,5-tetramethylbenzene, and 2.8 for 2-position of 1,2,3,5-tetramethylabenzene. all the figures being expressed against the standard value of 1.00 for toluene. The observed accelerating effect of neighboring methyl groups on the demethylation rates of crowded reactant molecules has been correlated with modified superdelocalizability in <I>z</I> direction for radical aromatic substitution. The latter values calculated by the extended Hückel molecular orbital method were: 0.4070, 0.4116, 0.4908, 0.4169, 0.4124, 0.4116, 0.4131, 0.4133, 0.4148, 0.4204, 0.4120, and 0.4029 (toluene) in the order given above. The general parallelism between the observed and the theoretical values may be taken as a support not only of the extention of the concept of superdelocalizability to radical aromatic substitution, but also of our mechanistic interpretation on the key reaction of hydrogenolyses.
- 公益社団法人 日本化学会の論文
著者
-
Arai Hiromichi
Department Of Materials Science And Technology Graduate School Of Engineering Science Kyushu Univers
-
Uchiyama Masao
Department Of Pharmacology Showa University School Of Medicine
-
Sato Yoshiki
Department Of Urban Management Kyoto University
-
Amano Akira
Department of Applied Chemistry, Faculty of Engineering, Tohoku University
-
Tominaga Hiroo
Department of Synthetic Chemistry, Faculty of Engineering, The University of Tokyo
-
Kunugi Taiseki
Department of Synthetic Chemistry, Faculty of Engineering, The University of Tokyo
-
Sato Yoshiki
Department of Applied Chemistry, Faculty of Engineering, Tohoku University
関連論文
- DEEP SUBSURFACE STRUCTURE ESTIMATED BY MICROTREMORS ARRAY OBSERVATIONS AND GRAVITY SURVEYS IN KASHIWAZAKI AREA, JAPAN
- Antidiabetic effects of Kampo medicines in a non-insulin-dependent diabetes mellitus model using KK-Ay mice
- An Effect of Anodic Reaction on the Current-Voltage Characteristics of Solid Oxide Fuel Cells
- Promotion of Methane Steam Reforming Using Ruthenium-Dispersed Microporous Alumina Membrane Reactor
- Removal of Dilute Nitrogen Oxide by the Absorption in Mn-Zr Oxide
- Liquid Phase Formation of Spinel Surface Layers on Hexaaluminate Microcrystals
- Thermoelectric Properties of Sintered FeSi_2 with Microstructural Modification
- Gas Permeation through Microporous Alumina Membranes Containing Highly Disperesed Metal Particles
- Retrarded Decomposition of the Trimethylammonium Moiety Observed on Photocatalytic Mineralization of Surfactants over TiO_2 Photocatalyst
- Room Temperature Preparation and Optical Properties of Titania and Silica Thin Films Embodying Polymer-Protected Ultrafine Metal Particles at High Concentrations
- Thermal decarbonylation of tropone.
- Metal Catalysts Supported on Zeolite. II. Dehydrogenation of Cyclohexane and Hydrodemethylation of Toluene over Zeolite-Supported Platinum Catalysts
- Dispersion State of Platinum on Zeolite and Hydrogenation of Ethylene
- Metal Catalysts Supported on Zeolite. I. A Study on Platinum Particles Distribution
- Oxidation of coals in liquid phases. VII. Oxidation of oxygen-containing model compounds of coal by oxygen in concentrated sodium hydroxide solutions.
- Pressure dependence of the reaction of thiolane with H and D atom.
- The reaction of dibutyl disulfide with hydrogen atom.
- Preparation and properties of nitrosyl complexes of molybdenum.
- Mechanism of Hydrogenolysis. I. Effect of Methyl Substituent on the Demethylation Rate of Polymethylbenzenes
- Mechanism of Hydrogenolysis. II. A Molecular Orbitals Study of Hydrogenolysis of Toluene
- Mechanism of Hydrogenolysis. III. Thermal Hydrogen Exchange and Demethylation of Toluene-2-d1, -3-d1, and -4-d1
- A method for solving design problem of multicomponent distillation.
- PREDICTION OF INITIAL PRODUCT DISTRIBUTIONS FROM PYROLYSIS OF NORMAL PARAFFINIC HYDROCARBONS
- Detection of Legionella pneumophila serogroup 1 in blood cultures from a patient treated with tumor necrosis factor-alpha inhibitor