527-53-7Relevant articles and documents
Experimental Determination of Internal Energy Barriers in the Gas-Phase Aromatic Alkylation by Dimethylchloronium Ions
Speranza, Maurizio,Laguzzi, Guiseppe
, p. 30 - 34 (1988)
The temperature and pressure dependence of the substrate selectivity of the alkylation of mesitylene (M) and p-xylene (X) by radiolytically formed CH3ClCH3+ ions have been investigated in CH3Cl gas at pressure between 50 and 760 Torr in the range 40-140 deg C.The Arrhenius plot of the empirical kM/kX ratio measured at 760 Torr is linear over the entire temperature range investigated, and its slope corresponds to a difference of 2.2 +/- 0.2 kcal mol-1 between the activation energy for the CH3ClCH3+ methylation of the p-xylene and mesitylene.A pressure-dependence study of the same competition reactions carried out at 100 deg C points to 300 Torr as the pressure limit, below which the correspondence between the phenomenological Arrhenius-plot slope and the actual activation-barrier difference is not any longer warranted.This conclusion is further corroborated by a comparison of the present results with those derived for the same reactions from reactant ion monitoring (RIM) "high-pressure" mass spectrometry at 0.5-1.2 Torr.The large discrepancy observed is interpreted as evidence that above 300 Torr the activation mechanism of the CH3ClCH3+ methylation of arenes, a typical ion-molecule process, is essentially thermal and that, below this limit, coexistence of both thermal and electrostatic activation mechanisms as well as incomplete equilibration of the internal energy of the reactants make Arrhenius plots hardly a measure of the activation barriers involved in the gas-phase aromatic alkylations.
The Selective Conversion of Methyl and Ethyl Acetate to High Content Alkyl Aromatic Hydrocarbons over H-ZSM5
Dabbagh, H. A.,Hassanpour, J.
, p. 1284 - 1290 (2020/12/02)
Abstract: This research is devoted to a catalytic process using the H-ZSM5 catalyst for the conversion of methyl and ethyl acetate to hydrocarbon aromatics. These reactions are carried out in a fixed bed reactor under atmospheric pressure at 370°C. The distribution of products was measured by GC-Mass spectrometer. The variation of weight hourly space velocity (WHSV) on the conversion of these esters to aromatic hydrocarbons showed a significant effect on carbon distribution. The deactivation catalyst by time was monitored using product selectivity and conversion. The production of alkyl and poly alkyl aromatic compounds was formed under controlled conditions. The advantages of these methods are the formation of a higher concentration of octane number booster poly alkyl aromatic compounds (mono-aromatics) from esters as starting materials. Moreover, the catalyst lifetime on stream was investigated and exhibited longer catalyst lifetime for ethyl acetate conversion than methyl acetate.
Reductive Cleavage of Unactivated Carbon-Cyano Bonds under Ammonia-Free Birch Conditions
An, Jie,Ding, Yuxuan,Luo, Shihui,Ma, Lifu
, (2019/11/29)
A general protocol for the reductive cleavage of unactivated carbon-cyano bonds in aliphatic nitriles has been achieved under single-electron-transfer conditions using Na/15-crown-5/H2O. Electron is supplied by the electride derived from bench-stable sodium dispersions and recoverable 15-crown-5. H2O provides the proton source and suppresses the reduction of aromatic moieties. Compared with the Na/NH3 electride system generated under traditional Birch conditions, this ammonia-free electride system is more practical and features better reactivity and chemoselectivity for the decyanations of a broad range of aliphatic nitriles.
