Catalytic conversion of propane to functionalized products

Abstract

Functionalization of propane has been investigated using various types of transition metal catalysts in the presence of K₂S₂O₈ as oxidant in CF₃COOH (TFA) solvent. In this reaction the primary products were iso-propyl alcohol and n-propyl alcohol. However, when the reaction was carried out in the TFA solvent, the primary products subsequently reacted with carboxylic acid, yielding iso-propyl trifluoroacetate as the dominant product and n-propyl trifluoroacetate as a minor product. Vanadyl acetylacetonate, VO(acac)₂ ([CH₃COCH=C(O-)CH₃]₂VO), exhibited the highest activity for propane functionalization. The optimum reaction conditions were 70ºC, 10 mmol of K₂S₂O₈, 5 mL of trifluoroacetic acid, 0.1 mmol of catalyst and 0.75 mmol of propane in a 25 mL autoclave. The turn over number was found to be 15.5 and the yield was 1.61 mol% based on propane when 98 mmol (7 atm) of propane was used in a 200 mL autoclave. The yield was as high as 89 mol% when 0.75 mmol (1 atm) of propane was used in a 25 mL autoclave under optimum reaction conditions.