Novel heteropolyanion-based ionic liquids (HPA-ILs) were obtained by combining Keggin heteropolyanions and organic cations and used as catalysts for an esterification reaction. The kinetic behaviors in the esterification of diethylene glycol monobutyl ether (DGBE) with acetic acid in the presence of HPA-ILs as catalysts were investigated systemically. Different types of HPA-ILs were used for the esterification of DGBE. Compared with H2SO4, H3PW12O40, and Amberlyst-15 resins, [BSEt3N]3PW12O40 and [BSmim]3PW12O40 exhibited excellent catalytic activities. The influences of reaction temperature, catalyst dosage, and reactant molar ratio on the conversion of DGBE were studied in detail. The kinetic data were successfully correlated by a pseudohomogeneous (PH) model in the temperature range of 343.15–363.15 K. The simulation values obtained by the kinetic model were in good agreement with the experimental data. Moreover, [BSEt3N]3PW12O40 and [BSmim]3PW12O40 could be easily recovered and reused six times without any obvious decrease in catalytic activity.

In order to have better insight into the structure–property relationship and promote the development of the potential applications of ionic liquids, it is essential to obtain more physicochemical property data. In this research, densities and viscosities of the binary mixtures of 1, 3-dimethylimidazolium dimethylphosphate ([Mmim][DMP]) and the alcohol (methanol, ethanol, propanol, or isopropanol) were measured within the temperature range from (293.15 to 323.15) K. The densities of these four mixtures were fitted by an empirical linear equation, and their viscosities were fitted by Vogel–Fucher–Tammann (VFT) equation. Moreover, the excess molar volumes (VE) and viscosity deviation (Δη) of four binary mixtures were calculated and fitted by a Redlich–Kister equation. In addition, the interactions and structure factors in these binary mixtures were discussed in detail based on the results. The results indicate that the obtained excess molar volumes and viscosity deviations for the four mixtures are negative at investigated temperatures.

The introduction of ionic liquids to alkylation process gives a choice for “green production” in the petrochemical and detergent industry. A lot of papers and patents have been published using chloroaluminate ionic liquid as a novel catalyst for alkylation with high reactivity and easy separation from reactants. These included the acidity, characterization, determination and catalysis technologies in batch and continuous operation mode for different scales. According to published data and several results of pilot alkylation,including the authors’ experience,the prospect of chloroaluminate ionic liquids for commercials was also discussed. It has been pointed out that there still are many difficulties and challenges to be overcome for commercial application of the ionic liquid catalyst.

Based on a compulsive mixing-reacting-separating-recycling small experimental setup,the continuous reaction performances of benzene alkylation with long chain olefins catalyzed by [BMIM]Cl-AlCl3 ionic liquid were investigated. Three different situations including normal continuous operation mode (reagent materials), sidetrack feeding from different axial positions along the static mixing reactor (reagent materials) and normal continuous alkylation using industrial paraffin and olefins materials were examined. Even under the relatively hypecritical reaction conditions, the single pass conversion of pure 1-dodecene could reach to nearly 100.0%, and the selectivity of 2-phenyl isomer was higher than 37.7%. Although the positions along the reactor for sidetrack feeding were different, the 100.0% single pass conversion of 1-dodecene was also attained before the outlet of the reactor. The refined industrial olefins as raw material could meet with the requirements of continuous alkylation. The influences of impurities such as di-olefins and non-benzene aromatics on the catalytic activity and stability should be studied further.

•Synthesis of propylene glycol methyl ether was investigated over ionic liquids (ILs).•The basicity and Kamlet-Taft parameters for ILs were estimated.•Basicity of ILs is mainly determined by the nature of anion.•Correlation between basicity/hydrogen bond properties- catalytic performance of ILs was studied.The relationship of basicity and hydrogen bond with catalytic performance was investigated in synthesis of propylene glycol methyl ether (PGME) catalyzed by various ILs ([Emim][OAC], [Bmim][OAC], [N2222][OAC], [EtOHN111][OAC], [N4444]Br, [Bmim][N(CN)2], [Bmim]Br, [Bmim][PF6]). The basicity and Kamlet-Taft parameters of each catalyst were evaluated by UV–visible spectroscopy. It was found the catalytic performance is the synergistic effect of basicity and hydrogen bond donating ability in the synthesis of PGME from PO and CH3OH, which is quite different from the conventional basic catalytic mechanism.The correlation between basicity, hydrogen bond properties and catalytic performance of ionic liquids was studied in synthesis of propylene glycol methyl ether (PGME).Download high-res image (125KB)Download full-size image