10160-87-9

5221-17-0

64-17-5

10160-87-9

General procedure for the synthesis of 3,3-diethoxyprop-1-yne from 2,3-dibromopropanal and ethanol: (2) Addition of sodium hydroxide to the anhydrous ethanol solution obtained in step (1). This was done by dissolving 155 kg of sodium hydroxide in 470 kg of anhydrous ethanol to prepare an anhydrous ethanol solution of sodium hydroxide, and refluxing the reaction mixture at 82 °C for 10 min. Upon completion of the reaction, separation and purification operations were carried out to obtain propargyl acetal diethyl acetal. First, the isolation and purification was carried out at 20 °C to remove solid impurities by centrifugation, followed by soaking in 80 kg of ethanol in a filter for 10 min, after which it was dried. The filtrate was transferred to a distillation flask and first distilled at atmospheric pressure until the temperature reached 100°C and the fractions were collected. Subsequently, decompression distillation was started, gradually increasing the vacuum to -0.09 MPa and maintaining the bottom temperature at 100 °C until the heating was stopped. Next, atmospheric distillation was carried out by setting the reflux ratio to 4:1, using a 600 mm packed column and controlling the bottom temperature at 120 °C. After distillation, the organic phases were combined and stirred with 10 kg of sodium hydroxide for 1 h, followed by filtration. The filtrate was added to the distillation unit and distilled under a vacuum of -0.097 MPa using a 600 mm distillation column with a set reflux ratio of 4:1. When the bottom temperature reached 50°C and the fraction temperature reached 42°C, the qualified product was collected. Finally, 60kg of qualified products with content >98% and moisture <0.1% were obtained.