while the temperature is maintained gas chromatography is used for tracking the reaction 30 ml water and 50 ml ether are added and stirred for 10 minutes layering is performed the ether layer is rinsed by 15 ml sodium chloride aqueous solution with the concentration of 5 dried by magnesium sulfate and filtered the solvent in filtrate is removed by distillation under reduced pressure to obtain crude product the residues are distilled under reduced pressure to collect 97 101 u00b0 c 1 mmhg fraction the gc content is measured the yield is calculated and the results are shown in the table below the products obtained are mixed to obtain 49 g crude product of enol ether which is used for the experiments under the condition of hydrolysis in the embodiments 10 to 16 below embodiment 9 preparation of c 14 aldehyde by hydrolysis of c 14 enol ether 7 11 0 g c 14 enol ether 7 0 05 mol prepared in the embodiment 1 100 g solvent tetrahydrofuran and 1 5 g paratoluenesulfonic acid are added to a 250 ml three necked bottle under the protection of nitrogen and are then uniformly stirred afterwards 22 g water is dropwise added for reaction for 1 day under stirring and at the temperature from 20 u00b0 c to 25 u00b0 c after the reaction is basically completed according to the tracking of gas chromatography solution prepared from 2 g sodium bicarbonate and 20 ml water is added for neutralization tetrahydrofuran is distilled out under reduced pressure by a water pump and then 100 ml cyclohexane is added layering is performed the organic layer is rinsed by 30 ml water and dried by anhydrous magnesium sulfate afterwards the solvent is recovered under reduced pressure to obtain 9 5 g.