1-Bromododecane → 1-Bromododecane

Participants

Reaction Conditions

Reaction Steps

After the reaction is completed, the reaction mixture contains a solution comprised of the 1-alkylimidazole and inorganic materials dissolved in the non-reactive aromatic solvent. The dissolved inorganic materials are unreacted base and inorganic salts which would be expected to form in the alkylation reaction. In addition, substantial amounts of insoluble unreacted base and inorganic salt are dispersed in the solution. For example, if imidazole is alkylated with 1-bromobutane in the presence of potassium hydroxide in toluene, the product mixture would contain a 1-butylimidazole-toluene solution in which are dissolved small amounts of potassium bromide and unreacted potassium hydroxide and undissolved potassium bromide and potassium hydroxide dispersed in the 1-butylimidazole-toluene solution. The solid inorganic material can be separated from the toluene solution by any means known to those skilled in the art such as by filtration. Inorganic material as defined above dissolved in the toluene solution can be removed by any means known to those skilled art such as by washing the organic phase with aqueous brine solutions. The imidazole product may be isolated from the solvent or may remain dissolved therein. The product imidazole can be isolated by any means known to those skilled in the art such as by distillation of the solvent. In a preferred embodiment of the present invention, about 1.5 moles of 2-methylimidazole and about 1.9 moles of potassium hydroxide powder are mixed with about 536 mL of toluene and heated to about 60° C. for 30 minutes with stirring. The temperature is then raised to 90° C. and about 1.36 moles of 1-bromododecane are added over 60 minutes. After the addition is complete, the reaction mixture is then maintained at 90° C. until the 1-bromododecane is no longer observable by GC analysis of the reaction mixture. The reaction mixture is then cooled and the organic phase and inorganic phases separated by filtration. The organic phase is washed with four 500 mL portions of brine and the toluene is removed at 40° C. under vacuum leaving a 99 mole % yield of N-dodecyl-2-methylimidazole relative to 1-bromododecane.

Provenance & Evidence