Synthesis of tert-butyl acetate via eco-friendly additive reaction over mesoprous silica catalysts with balanced Brönsted and Lewis acid sites

The dual-modified SBA-15 materials (A–S–Si) with Al ions inserting in the framework and −SO₃H groups grafting on the pore wall were prepared via a co-condensation method and characterized by a series of techniques. The characterization results implied that the A–S–Si samples have typically mesoporous structure and different acid properties. The catalytic performance of A–S–Si catalysts in the additive reaction of acetic acid with isobutene was studied. The results showed that the conversion of acetic acid strongly depended on the Brönsted acidity, while the selectivity of tert-butyl acetate (TBAC) was linear correlated with the ratio of Brönsted and Lewis acid amounts. The conversion of acetic acid could reach 72 % with the selectivity of TBAC as high as 97 % over A₅–S₁₀–Si with balanced Brönsted and Lewis acid under the optimal conditions. An additional advantage was that the dual-modified catalyst can be recycled and regenerate with good stability.