To a 50 mL three-necked flask was added 1.70 g (0.01 mol) of gallic acid, a quantity of isoamyl alcohol and p-toluenesulfonic acid, a magnetic stirrer was put in place, a thermometer was inserted, and a reflux device was installed. The magnetic stirring knob was turned on and the reflux was heated in an oil bath at different temperatures for a period of time. Upon completion of the reaction, the reaction solution was transferred to a separatory funnel and the organic phase was washed by adding an equal volume of saturated sodium bicarbonate solution to remove unreacted
gallic acid, and then washed to neutrality with water. Decompression distillation of the organic phase to remove excess alcohol (can be recycled), to the remaining solid add an appropriate amount of chloroform and filtered while hot, until the chloroform volatilization is complete with an appropriate amount of ethyl acetate to dissolve the precipitate, filtration, collection of filtrate, concentration under reduced pressure and drying to obtain the product.
