The Study On The Applications Of Room Temperature Ionic Liquids In Alkylation And Condensation Reactions

In the part one, we reported a novel method for the synthesis of phenacyl esters by reaction of carboxylic acids with α-bromoacetophenone promoted by potassium fluoride. Additionally, we reported on the reactions between alkyl halides and cyclic imides, N-monosubstituted sulfonamides, 2-mercaptobenzothia(xa)zole or sodium arenesulfinates respectively. We performed these reactions in various ionic liquids containing different kind of anions and cations and also in common molecular solvents to compare the reaction conditions, rates and the yields of products. The results showed that ionic liquid is an effective reaction medium for these reactions.In the part two, we reported the classical Knoevenagel condensation between aromatic aldehydes and acyclic active methylene compounds or cyclic active methylene compounds containing heteroatom such as (2-thio)barbituric acid, Meldrum's acid using ionic liquids as reaction medium. We investigated the efficacy of different ionic liquids, the scope of reactive substrates, the generality, the substituent effect of aromatic aldehydes and compared with other previously reported procedures. The experimental results showed that ionic liquids, especially, ethylammonium nitrate (EAN) which played a dual role as solvent and promoter in the Knoevenagel condensation were truly comparable with classical organic solvents with the advantage of rate acceleration and increase of yields and selectivity. Besides, we found the Gewald synthesis of 2-aminothiophenes catalyzed by ethylenediammonium diacetate (EDDA) could be efficiently performed in the ionic liquids, [Bmim]BF₄ and [Bmim]PF₆.In summary, the above alkylation, condensation reactions and the synthetic methods possess such advantages as readily available starting materials, mild reaction conditions, simple operation, high selectivity, high yields, environmentally benign and the potential for recycling of ionic liquids.