materials drawn out from the bottom of the azeotropic distillation tower were fed into the lower part of the water washing tower and the mass flow of materials in the bottom of the tower was 100 kg hr then the water was inpoured into the upper part of the water washing tower and the mass flow of water was 500 kg hr the mass flow ratio of the water to the materials was 5 other steps were the same as example 1 the heavy hydrocarbon obtained in reaction and accumulated in the system can be taken out in time after the water washing operation and the content of the heavy hydrocarbon in the bottom of the azeotropic distillation tower was controlled in the range of 1 to 5 by mass after the device was operated continuously for six months no obvious phenomenon of scaling existed in reboiler on the bottom of the azeotropic distillation tower the mixture consisting of sec butyl acetate 52 79 acetic acid 42 71 hydrocarbon and other materials 4 5 mass percentage were fed into the azeotropic distillation tower and then the water as the azeotropic agent was inpoured into the azeotropic distillation tower with the mass ratio of sec butyl acetate to water being 4 1 the temperature in the bottom of the azeotropic distillation tower was 128 and the temperature in the top of the tower was 86 5 the distilled materials from the top of the tower after the azeotropic distillation consisted of by mass sec butyl acetate 95 94 acetic acid 0 01 water 1 hydrocarbon and other materials 3.