Novel basic ionic liquids from cyclic guanidines and amidines – new catalysts for transesterification of oleochemicals

Abstract

BACKGROUND: Alkylguanidinium and alkylamidinium hydroxides have been developed as new basic ionic liquids for the first time from cyclic guanidine (TBD) and amidines (DBN, DBU). The method of preparation of [bmim]OH decribed in the literature was adopted for the synthesis of new ionic liquids. Synthesis was carried out using cyclohexane as the solvent for the synthesis of alkylguanidine and alkylamidine bromides. Anion metathesis was carried out over anionic resins in water as solvent. The structures of the new ionic liquids were confirmed by spectral analysis. The catalytic activity of the new ionic liquids was tested in transesterification of fatty acid methyl esters with trimethylolpropane, neopentyl glycol and 2-ethylhexyl alcohol. RESULTS: The new ionic liquids have good thermal stability and can be applied for transesterification processes. The highest conversion of FAME (83%) was obtained for TMP ester of oleic acid and ionic liquid [TBD-Bu]OH.CONCLUSION: Among the ionic liquids derived from cyclic guanidine and amidine only ionic liquids obtained from TBD are good catalysts for transesterification of FAME and polyols. In comparision with [bmim]OH, catalytic activity of TBD ionic liquids was comparable in the synthesis of TMP ester but better in the synthesis of 2EH esters.

Highly water soluble room temperature superionic liquids of APIs

“…22 More precisely, the given signal varies ca. 5 13 C NMR resonance of the quaternary carbon C=N + occurs downfield as reported, 23 reflecting the weaker shielding of the protonated amidine core. When the spectra are collected in CDCl3, the observed variation is ca.…”

DBU-Based Protic Ionic Liquids for CO2 Capture

“…Also, more observations about the behavior of different ILs in CO 2 absorption remain to be uncovered. 1,8-Diazabicyclo[5.4.0]­undec-7-ene (DBU), as the traditional superbase, has been used in many organic reactions due to its strong alkaline nature. , In recent years, some research about DBU-based ILs has been carried out to study their properties , and applications. − In 2016, Wang et al demonstrated a new method for efficient synthesis of 3­(2 H )-furanones triggered by CO 2 using a series of base-functionalized ionic liquids, including DBU imidazole ([DBUH + ]­[Im − ]), composed by different cations and anions, which addressed the importance of the basicity of the anion. Consequently, to further enrich the understanding about the behavior of DBU-based ILs on CO 2 capture, in this Article, a series of DBU-based ILs prepared from DBU and different imidazole-based anions were synthesized.…”

Highly efficient carbene and polycarbene catalysis of the transesterification reaction

“…Among them special attention was paid to guanidine derivatives (see also [35][36][37][38] ), which having basicities close to carbenes do not form soaps during the reaction and their catalytic efficiencies are close to those for sodium hydroxide and methoxide (for 1,5,7-triazabicyclo[4.4.0]dec-5-ene TBD TON is no more than 270 at 70 C, 1 mol% of a catalyst, the molar ratio of rapeseed oil : methanol is 1:2.3). As can be seen from the data obtained in the present work carbenes are considerably more efficient (TON 2667 at room temperature, 0,1 mol% of a catalyst, the molar ratio of sunflower oil : methanol is 1 :20).…”