Microemulsions of N-alkylimidazolium ionic liquid and their performance as microreactors for the photocycloaddition of 9-substituted anthracenes.
The phase behavior of the ternary system consisting of an ionic liquid (1-tetradecyl-3-methylimidazolium bromide [C14mim]Br), p-xylene, and water were investigated. Depending on the composition of the ternary system, formation of hexagonal and lamellar liquid crystals as well as microemulsions was observed. 1H NMR spectroscopy study, 2D ROESY spectroscopic analysis, and rheological measurements of the microemulsions indicated that p-xylene is preferably located in the hydrophobic core and the palisade shells of the microemulsions. The sizes of the microemulsion droplets for the samples with water/[C14mim]Br ratio of 78:22 are measured by both dynamic light scattering (DLS) and transmission electron microscopy with the freeze-fracture technique (FF-TEM). Upon change of the mole ratio of the solubilized xylene to [C14mim]Br from 0 to 2.4, the diameters of the microemulsion droplets increase from ca. 20 to 90 nm and size distribution gets broad. These microemulsions can solubilize and preorientate anthracene derivatives with a polar 9-substituent, and thus may enhance the head-to-head cyclomers in the photocyclization of these substrates.
Li
Xin-Wei
XW
Key Laboratory of Colloid and Interface Chemistry, Shandong University, Ministry of Education, Jinan 250100, China.
Zhang
Jin
J
Zheng
Li-Qiang
LQ
Chen
Bin
B
Wu
Li-Zhu
LZ
Lv
Feng-Feng
FF
Dong
Bin
B
Tung
Chen-Ho
CH