Structure Effect of Imidazolium-Based Dicationic Ionic Liquids on Claisen Rearrangement

Abstract

The melting points of DILs were determined by Stuart SMP3 apparatus. UV-VIS spectra were recorded on UV/VIS Spectrometer Lambda 25. High-resolution mass spectra were obtained with Agilent 6230 TOF LC/MS instrument. Negative-ion ESI-MS analysis was performed on Agilent 6230 TOF LC/MS mass spectrometer. ESI-MS spectra were obtained for the solutions (10 -3 M) of DILs in acetonitrile-water (1:1, v:v). 5 µL of the samples were injected directly into the spectrometer at a constant flow 5 µL/min. Source was used with the following parameters: negative ionization mode, drying gas flow 10 mL/min and 200 °C temperature, fragmentor ionization was set in a range of 0 to 130 V. N 2 was used as the sheath gas at flow 8 ml/min and 200 °C temperature. The mass scan range was from m/z 50 to 3000. Peak detection and spectrum extraction were performed with MassHunter Software (Agilent). Thermogravimetric analysis was performed by SII Extar6000 TG-DTA6300 under nitrogen atmosphere (temperature gradient 50…500 o C, heating rate -10 o C/min). The products of the Claisen rearrangement were identified by GC (Shimadzu GC-2010) using Restek Rtx®-1 Ms column (30 m x 0,25 mm x 0,25 µm) equipped with mass spectrometer (Shimadzu GC/MS-QP2010). Quantitative analysis of the reaction mixture was performed by GC (YL6100 GC) using the same column equipped with a flame ionization detector (FID). Helium was exploited as the carrier gas (flow rate -1 mL/min).

Systematic Synthesis and Properties Evaluation of Dicationic Ionic Liquids, and a Glance Into a Potential New Field

“…1 H NMR (D 2 O) δ 8.86 (s, 2H, 2 × H-2), 7.52 (bs, 4H, 2 × H-4, 2 × H-5), 4.32 (t, 4H, J = 7.2 Hz, 2 × C H 2 N), 4.19 (t, 4H, J = 7.2 Hz, 2 × C H 2 N), 2.56 (qui, 2H, J = 7.3 Hz, NCH 2 C H 2 CH 2 N), 1.84 (qui, 4H, J = 7.3 Hz, NCH 2 C H 2 C 2 H 5 ), 1.30 (sext, 4H, J = 7.5 Hz, 2 × C H 2 CH 3 ), 0.90 (t, 6H, J = 7.3 Hz, 2 × CH 3 ); 13 C NMR (D 2 O) δ 135.3 (2 × C-2), 122.7, 122.1 (2 × C-4, 2 × C-5), 49.4, 46.4 (each 2 × C H 2 N), 31.1 (2 × NCH 2 C H 2 C 2 H 5 ), 29.6 (NCH 2 C H 2 CH 2 N), 18.7 (2 × C H 2 CH 3 ), 12.6 (2 × C H 3 ). NMR ( 1 H) data were in agreement with those reported (Lee et al, 2010; Priede et al, 2014).…”

“…a Youan et al (2017) .b Priede et al (2014) .c Zhang et al (2018) .d Lee et al (2010) .e Yang et al (2014) .f Lee et al (2011) .…”

Ionic liquids and their modification with lithium salts –synthesis and studies

“…The first, which has been known for more than thirty years, requires alkylation of 1-substituted imidazoles by trialkyl phosphates, mainly by trimethyl phosphate (route A, Fig. 3.1) [17][18][19][20][21][22][23][24][25]. This is the method for preparation of different 1-alkyl-3-methylimidazolium dimethyl phosphates (2).…”

“…Like other ILs, IA-DMPs most frequently are used as reaction media or/and catalysts in organic synthesis. This field of application has lately been also quite extensively investigated at the University of Latvia [19][20][21][22][23][24][25][26]. The use of IA-DMP in other research areas (electrochemistry, extraction processes, formation of composite materials, etc.)…”

Surface Passivation of Bare Boron Nanoparticles Using New Dicyanamide-Based Dicationic Ionic Liquid

“…Dicationic ionic liquids (DCILs), a type of IL, in which two monocations are combined into a dication have been recently synthesized and reported. − These new types of ILs are considered as solid or melting salts near room temperature. Therefore, they could afford new supramolecules that are suitable for various applications as a result of their high thermal properties and broad liquid range. − …”