SBA-15-SO₃H-Confined Acidic Ionic Liquid

Key words

mesoporous silica - SBA-15 - ionic liquids - esterification

Significance

Esterification of carboxylic acids with alcohols using an acidic ionic liquid confined to SBA-15-SO₃H (IL@SBA-15-Pr-SO₃H) as a catalyst was described. IL@SBA-15-Pr-SO₃H consists of ordered mesoporous silica SBA-15-SO₃H where an ionic liquid [MOIm]HSO₄ (1-methyl-3-octylimidazolium hydrogen sulfate) was charged. The catalyst promoted the esterification of various carboxylic acids and alcohols at room temperature under solvent-free conditions to give the corresponding esters in 87–99% yield.

 

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Comment

IL@SBA-15-Pr-SO₃H was recovered and reused three times in the direct esterification of acetic acid with 1-octanol (GC yield: 1^st use: 100%, 2^nd use: 94%, 3^rd use: 90%, 4^th use: 89%). Both N₂ adsorption–desorption and elemental microanalysis demonstrated that catalyst loss of ≈7% occurred after the 4^th run. SBA-15-Pr-SO₃H, [MOIm]HSO₄ (IL), IL@SBA-15, H₂SO₄, and SBA-15 showed lower catalytic activity in the esterification of acetic acid with 1-octanol under similar conditions.

 

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