ABSTRACT
Low-viscous homologue-paired liquids (HPLs) are designed and employed as special non-ionic deep eutectic solvents for selective separation of SO2 from CO2 and N2. The HPLs are found to have excellent inherent properties (e.g., low cost, volatility and viscosity), high absorption capacity, fast absorption rate, and moderate Lewis acid-base interaction with SO2. Regeneration experiments are done to show their excellent recyclability, and industrial desulfurization is exemplified in a small column with suitable parameters to show their potential as SO2 absorbents.
ABSTRACT
In general, Friedel-Crafts reaction is incompatible with amines due to the Lewis acidity of the catalysts. Recently, we reported that cyclic diaminocarbene-Gold(I) can be used as catalyst for the Friedel-Crafts alkylation between aromatic amines and alkenes. Herein, a systematically theoretical research was performed on this rare Friedel-Crafts reaction. The adopted calculation method is accurate enough to reproduce the crystal structure of the catalyst. It was found that the reactions followed the electrophilic aromatic substitution mechanism. The gold cation can activate the C=C double bond and generate the electrophilic group which can be attacked by the aromatic ring. The para-product is more energy favorable which agrees well with the experimental results. The reaction of α-methylstyrene follows the Markovnikov rule, and the activation energy to generate the branched product of methylstyrene is lower than that producing the linear product. However, the reaction of butanone follows the anti-Markovnikov rule, and the activation energy to generate the branched product of butanone is higher than that producing the linear product. These calculation results reveal the mechanism of this new Friedel-Crafts reaction. It can well explain the high para-selectivity and the substrate-dependent of the product structures in the experiment.
