Gas-phase alkylation and halogenomethylation by free dialkylhalogenonium and halogenomethylium ions

Ethyl cation transfer from diethylchloronium to alkyl aromatics studied by high pressure mass spectrometry

“…Dialkylhalonium ions have been shown to be excellent alkylating agent for aromatic hydrocarbons in both gas and liquid phases (1)(2)(3)(4). Dimethylchloronium (CH3C1CH:) has been extensively studied in the gas phase because it is very readily prepared from methanelmethyl chloride mixtures in a chemical ionization (CI) source (3,4).…”

The Gas-Phase Reactivity ofp-Me3Si-Substituted 1,3-Diphenylpropane Towards Charged Electrophiles: Intra- and Interannular Hydrogen Migrations

“…As expected from the use of a purely methylating agent, Me 2 Cl from the radiolysis of MeCl, [15] as reactant ion, only methylated and methyldesilylated products are detected for both substrates. The isomeric distribution of the desilylated products from p-TSDPP and p-TST shows that only a fraction (50 % and 30 %, respectively) of electrophilic attack is directed to the (silylated) para position.…”

Gas-Phase Alkylation of Trimethylbenzenes by i-C3H+ 7 and t-C4H+ 9. Evidence for Steric Hindrance in Deprotonation of Gaseous Arenium Ions

“…The following columns were used: i-a 2-m long, 2-mm i. d. glass column, packed with 3% Carbowax 20M on WHP-DMCS 100/120 mesh Chromosorb, ii-a 7-m long, 3 Supelcoport, iii-a 100-m long, 0.25-min i. d. stainless steel capillary column coated with MBMA stationary phase, iv-a 50-m long, 0.20-mm i. d. quartz capillary column, deactivated with Carbowax 20M and coated with methyl silicone SP-2100 fluid, v-a 2-m long, 3.1-nim i. d. glass column, packed with 5% SP-1200 + 1.25% Bentone 34 on 100/120 mesh Supelcoport. Column i-was used at 90°C for the analysis of the products from the ferf-butylation of pseudocumene and mesitylene, and at 70°C for the analysis of the products from the toluene-hemimellitene and toluene-pseudocumene pairs.…”

“…The study of a variety of gaseous reagents, including X^ (X = H, D, T), Ci -C4 carbenium ions, dimethylhalonium and acetylium cations [3] has suggested a general, two-step reaction model, involving formation of a gaseous arenium ion…”

“…The application of radiolytic techniques to the study of gas-phase aromatic substitution has proven fruitful, particularly in permitting the direct evaluation of the selectivity and the steric requirements of charged electrophiles in the absence of their solvation shells, counterions, and in general of the complicating phenomena encountered in Solution [1][2][3].…”