RESEARCH ON THE UTILIZATION OF THE BYPRODUCTS OF PULP MANUFACTURE

Abstract

The two-stage oxidation method of p-cymene was studied with the object of the preparation of terephthalic acid.In the first stage, amounts of 10g. p-cymene were oxidized with 50cc of 40% nitric acid at 95_??_100°C for 1hr. in an open bottle dipped in oil bath and then the products were transfered to a seald tube containing 50cc of 40% nitric acid and was heated at 125°C for 3hrs. (maximum pressure; about 3.2kg/cm2). In these experiments, the maximum yield of terephthalic acid was 74.7%.From the analysis of the first stage products, it was found that the main products in the first oxidation were p-toluic acid and p-methylacetophenone. The mixtures of p-toluic acid and p-methylacetophenone at various ratio were oxidized under the same conditions as the second oxidation. In these experiments the larger amount of p-methylactophenone in the mixture the larger is the yield of terephthalic acid. From these results, it was found that the best yield of terephthalic acid in the second oxidations is obtainable by oxidizing the first oxidation products which has the maximum contents of p-methylacetophenone.