Use of supercritical carbon dioxide in alkylation reactions

The environmental issues arising due to the usage of conventional solvents as well as the generation of hazardous chemical waste have driven many research efforts intended to designing new benign chemical processing approaches that can either exclude or considerably alleviate pollution. Alkylation reactions are of high interest as they occupy upper positions in both laboratory and industrial scales. Traditional alkylation reactions generally require long reaction duration and low temperature and, in addition, use environmentally unfavorable catalysts. The use of supercritical carbon dioxide (scCO₂) as a reaction medium is prospective to offer a substantial role in environmentally benign alkylation reaction conditions, which can be tuned to achieve high product selectivity and aided with easy solvent removal. In this chapter, the benefits of scCO₂-based reaction media in both optimizing the solid-acid catalyst activity and attaining desired product selectivity are reviewed for various alkylation processes.