New Guanidinium-based Room-temperature Ionic Liquids.
Substituent and Anion Effect on Density and Solubility in Water
Milen G. Bogdanova,c, Desislava Petkovaa,c, Stanimira Hristevaa,c, Ivan Svinyarova,c, and Willi Kantlehnerb,c
aFaculty of Chemistry, University of Sofia, 1, J. Bourchier Blvd., 1164 Sofia, Bulgaria
bInstitut f¨ur Organische Chemie, Universit¨at Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany
cFakult¨at Chemie/Organische Chemie, Hochschule Aalen, Beethovenstraße 1, 73430 Aalen, Germany
Reprint requests to Dr. Milen G. Bogdanov. E-mail: mbogdanov@chem.uni-sofia.bg Z. Naturforsch.2010,65b,37 – 48; received October 28, 2009
Dedicated to Professor Klaus Peseke on the occasion of his 70thbirthday
In order to examine the influence of the alkyl chain length on some physical properties of guani- dinium salts, the synthesis of a homologous series of newN-n-alkylsubstitutedN,N-diethyl-N,N- di-n-propyl-N-n-hexyl guanidinium ionic liquids (gILs), containing chloride (Cl), tetrafluoroborate (BF4), acesulfamate (Ace), saccharinate (Sac), and tosylate (Tos) as anions, is reported.Cnnn-gILAce, Cnnn-gILSac, andCnnn-gILBF444were obtained by ion exchange reaction of the corresponding hexasub- stituted guanidinium chlorides (Cnnn-gCl,n= 3, 4, 6, 8, 10), which were synthesized by a quaterniza- tion reaction of the pentaalkyl-substituted guanidine3and the corresponding alkylchloride in DMF.
The tosylates gILsCnnn-gTos(n= 1, 2, 4, 6, 8, 10) were synthesized by alkylation of3with the corre- sponding alkyltosylates. Some physical properties, such as solubility in water and organic solvents, refractive index and density, are considered as a function of the length of then-alkyl substituent R and the nature of the anion.
Key words:Ionic Liquids, Guanidinium Salts, Density, Quaternization Reaction, DMF
