Synthesis Oxalic Acid from Durian skin (Durio Zibethinus) with Alkali Smelting Method

Abstract

In Indonesia, Durian is known as the king of fruit. Many people like the thorny fruit which has a distinctive taste and smell. The weight percentage of fruit flesh, or the edible part of the fruit, is only 20.52%. Thus, about 79.48% of the fruit, including the skin and seeds of the durian fruit, is inedible. Therefore, the waste produced from durian fruit skin is very large because durian fruit skin contains lignocellulosic materials such as lignin, hemicellulose and cellulose. Based on the data above, durian fruit skin waste can be used to produce oxalic acid. The purpose of this paper is to find out how to make oxalic acid from the remains of durian fruit peel, the most optimal concentration of NaOH used to produce oxalic acid, and the optimum melting time obtained. Oxalic acid is made through an alkali melting process which consists of several stages, including: precipitation with CaCl2, acidification with H2SO4 and crystallization. The alkali used was NaOH with various concentrations of 3N, 4N, and 5N with cooking times of 30, 40, and 60 minutes at a temperature of 95^oC. The optimum concentration of NaOH and optimum melting time to make oxalic acid from durian fruit peel waste was at the solution concentration. NaOH 4N with time of 60 minutes to produce a % yield of 27,80%.