23/05/2007 · Vasile I

Recent Progress in Ionic Liquids and their Applications in Organic Synthesis ..

CHEMISTRY - University of Washington

The diversity of possible combinations of organic cation and suitable inorganic or organic anion allows the design of ionic liquids suitable for the various organic reactions resulted in increased chemical yields, increased chemo-, regio-, and stereo selectivity as well as recycling of the catalyst [6]. The covalent bond between organic cation/organic or inorganic anion of an ionic liquid and some functional group such as NH2, OH, SH, OR, PPh2, Si(OR)3, urea and thiourea, metal complexes etc. impart the capacity to behave ionic liquid as an reagent, catalyst along with solvent characteristic in the chemical reactions. For example,

Zinc Oxide—From Synthesis to Application: A Review - MDPI

The behavior of ionic liquids may be acidic, basic or organocatalyst depending upon the functional group attached either to the anion or cation or both of an ordinary ionic liquid. In view of the acidic behavior of ionic liquids, the replacement of harmful acids by reusable ionic liquids is one of the great catalytic systems in organic synthesis. The ionic liquids possessing acidic behavior were exploited as catalysts for many organic transformations like Koch carbonization, Pechmann reaction, Aza-Michael reaction, aldol condensation, esterification of alcohols, Beckmann rearrangement, oxidation reaction, Prins reaction and Mannich reactions to mention a few [5].

While the use of ionic liquids as solvents for electrodeposition1 is fairly well-developed, the use of these solvents in inorganic synthesis is still largely unexplored.

Ion-exchange Resin | Ionic Systems

Ionic liquids based on imidazolium, pyridinium, and alkylammonium salts were investigated as solvents in free radical polymerization of the model monomer -butyl methacrylate. The properties of the ionic liquids were systematically varied by changing the length of the alkyl substituents on the cations, and by employing different anions such as tetrafluoroborate, hexafluorophosphate, tosylate, triflate, alkyl sulfates and dimethyl phosphate. Results were compared to analogous polymerizations in toluene and in bulk. The solvents have no detectable influence on polymer tacticity. However, the molar masses obtained and the degree of polymerization, respectively, are very sensitive to the choice of the solvent. The degrees of polymerization are significantly higher when polymerizations were carried out in ionic liquids compared to polymerization in toluene, and can even exceed the values obtained by bulk polymerization. Imidazolium salts unsubstituted at C-2 result in an increase in the degree of polymerization of the poly(butyl methacrylate) with increasing viscosity of these ionic liquids. Methyl substitution at C-2 of the imidazolium ion results in an increase in the viscosity of the ionic liquid and in a viscosity independent degree of polymerization of the poly(butyl methacrylate). Ionic liquids based on imidazolium salts seem preferable over pyridinium and alkylammonium salts because of the higher degree of polymerization of the poly(butyl methacrylate)s obtained in the imidazolium salts. The glass transition temperatures and thermal stabilities are higher for poly(butyl methacrylate)s synthesized in the ionic liquids compared to the polymer made in toluene.

Clean Chemical Synthesis in Water - Organic chemistry

Typical synthetic methods involve high pressure, which is a hinderance to the use of organic ligands for control over size and shape. The goal of this project is to develop an ambient pressure solution-phase synthesis of crystalline CrO2 nanoparticles with control over the size, shape and surface chemistry.We require a solvent with the ability to withstand oxidation or reduction over a large potential range. Ionic liquids, solvent systems that have not yet been well explored for nanoparticle synthesis, can have extremely large electrochemical windows.

Clean Chemical Synthesis in Water

39. Antonietti M, Kuang D, Smarsly B, Zhou Y. Ionic liquids for the convenient synthesis of functional nanoparticles and other inorganic nanostructures. 2004;43:4988-92