向日葵壳水解—氧化—水解法制取草酸新工艺研究

New Technology for Preparation of Oxalic Acid from Sunflower Shell by Hydrolysis-Oxidation-Hydrolysis

研究了以植物纤维向日葵壳为原料，采用水解-氧化-水解法制取草酸（乙二酸）的新工艺。与用同类原料、其他方法制草酸相比，本工艺在提高产率、降低生产成本以及易于工业化方面有很大突破。在H2SO4质量分数为70％，原料浸泡时间3h以上，m（HNO3）：m（向日葵壳）=2．1：1．0，氧化-水解反应时间5h。反应温度65～70℃的条件下，草酸二水合物收率可达78．5％。

The preparation method of oxalic acid from plant fibre sunflower shell by hydrolysis- oxidation - hydrol- ysis was investigated. This method could increase yield, reduce cost, and industrialize easily as compared with other methods of preparing oxalic acid with the same raw material. The yield of oxalic acid dehydrate was up to 78.5 % under the conditions of H2SO4 concentration 70 %, marinating time for sunflower shell 〉 3h, m （ HNO3 ） ： m （sunflower shell） = 2.1 ： 1.0, oxidation - hydrolysis time 5 h, and reaction temperature 65 - 70℃.