for example a spinning band column can be used to distill the product such distillation can readily produce fractions or cuts containing at least about 90 menthofuran and in some cases as high as 99 with little or no loss the following examples show ways we have operated our process and obtained menthofuran the examples should not be construed as limiting the invention all temperatures are given in degrees centigrade and all percentages are weight percentages unless otherwise specified into a 3 liter 3 neck flask fitted with a thermometer addition funnel and a stirrer were placed 308 g 2 moles of isopulegol 400 g 3 8 moles of sodium carbonate and 900 ml methylene chloride the reaction mixture was cooled to about 0 u00b0 c and 320 ml about 2 5 moles of 40 peracetic acid containing 12 g sodium acetate was added the addition was controlled so that a reaction temperature of about 25 u00b0 c was maintained the addition took about 30 minutes the flask was held at 25 u00b0 to 30 u00b0 c for 3 hours the reaction mixture was allowed to stir overnight in order to work up water was added to dissolve the salts the organic portion was then washed with water cold 5 sodium hydroxide sodium bisulfite solution and water successively solvent was removed in a rotary evaporator at 35 u00b0 to 40 u00b0 c about 418 g of product was obtained containing about 63 isopulegol epoxide 3 hydroxy p menthan 8 9 oxide and.