Sun Xuewen

Alkylation mechanism of benzene with 1-dodecene catalyzed by Et3NHCl-AlCl3

The isotope exchange method was employed to investigate the catalytic mechanism of ionic liquid in alkylation of benzenes with olefins. It is proposed that alkylation was induced by the Lewis acid AlCl3 which attracted π electrons of 1-dodecene to shift toward 1-carbon, thus forming a carbonium ion. The carbonium ion further reacted with benzenes to form a complex. Due to unstabilit of the complex, a deuterated ring proton was transferred into an electronegative 1-carbon of the side chain to substitute for the AlCl3, accordingly 2-phenyldodecane was generated.

Alkylation of benzene with propylene catalyzed by FeCl3-chloropyridine ionic liquid

Alkylation of benzene with propylene was carried out with FeCl3-chloro-butyl-pyridine (FeCl3-[bpc]) ionic liquid as catalyst to obtain cumene. Significant improvements in propylene conversion and cumene selectivity under mild reaction conditions were attained by modification of the catalyst with HCl. Under 20°C, 0.1 MPa, reaction time 5 min, mole ratio of benzene to propylene 10:1 and mass ratio of FeCl3-[bpc] to benzene 1:100, conversion of propylene can increase from 83.60% to 100.00% and selectivity of cumene can increase from 90.86% to 98.47%. If reaction is carried out in following two stages, the result will be very good. At the initial stage of the reaction, alkylation is the main reaction and a higher conversion of propylene is obtained at a lower temperature. At the later stage of the reaction, transalkylation is the main reaction and selectivity to cumene can be increased by appropriately raising the reaction temperature.

The chemical fundamentals for heavy oil supercritical fluid extraction and multi-stage separation technology

The supercritical fluid extraction and fractionation method (SFEF) can realize deep cut and separation for heavy oils, which have provided a powerful tool for heavy oil chemistry research. This work summarizes recent research progress on aspects include the association and aggregation, the diffusion phenomena of SFEF cuts, the association and interaction between trace metal species and asphaltene in liquid solvent and supercritical conditions. The molecular level composition changes in supercritical extraction, thermal reaction and hydrotreating processes will also be discussed. The inspiration of the relevant chemical fundamentals to the development of heavy oil multi-stage separation by supercritical fluid processing technologies will be introduced as well.