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The current work utilizes the ab initio density functional theory (DFT) to develop a molecular level of the mechanistic understanding on the phenol alkylation in the presence of a cation-exchange resin catalyst, Amberlyst-15. The catalyst is modeled with the benzene sulfonic acid, and the effect of this acid on olefins such as isopropene (i-Pr) and tributene (t-Bu) in a phenol solution mimics the experimental condition. A neutral-pathway mechanism is established to account for early-stage high concentration of the phenolic ether observed in experiments. The mechanism involves an exothermic reaction between olefin and the benzene sulfonic acid to form ester followed by three reaction pathways leading to direct O-alkylation, o-C-alkylation, and p-C-alkylation. Our calculations conclude that O-alkylation to form the phenolic ether is the most energetically favorable in the neutral condition. An ionic rearrangement mechanism describes intramolecular migrations of the alkyl group from the phenolic ether to form C-alkylphenols, while the positively charged protonation significantly lowers transition barriers for these migrations. The ionic rearrangement mechanism accounts for high yields of o-C-alkylphenol and p-C-alkylphenol. Competition between the H atom and the alkyl R group at the substitutive site of the protonated ortho configuration is found to be the determining factor to the ortho/para ratio of C-alkylation products.

The neutralization reaction between a concentrated sulfuric acid droplet and a series of model marine cylinder lubricants (MCLs) formulated with an overbased sulfonate and a series of different nonionic surfactants was studied using a capillary video-microscope technique at room temperature and a phase transfer neutralization rate test at several temperatures up to 55 °C. The model MCLs were characterized using dynamic light scattering and transmission electron microscopy. On the basis of the observations, a mechanism is proposed for the neutralization reaction which involves the initial formation of a mixed reverse micelle system between the overbased sulfonate and the nonionic surfactant followed by the neutralization reaction at the aqueous acid/oil interface to form calcium sulfate crystals. The rate of the neutralization reaction is enhanced by the presence of the nonionic surfactants in the model MCLs and is consistent with the formation of the mixed micelle systems which makes the basic core (CaCO 3 /Ca(OH) 2 ) of the overbased sulfonate more accessible to the aqueous acid due to the increased size and flexibility of the overbased sulfonate reverse micelle.