粉状白钨酸的研究(Ⅴ)——12-钨磷酸的直接制备以及用正丁醚的提纯法

Studies on White Powdery Tungstic Acid (Ⅴ)——Direct Preparation of 12-Tungstophosphoric Acid from White Powdery Tungstic Acid and Its Purification through n-Butyl Ether Extraction

12-钨磷酸的应用,近年来发展迅速,有从实验室合成转为工业生产的趋势。本报告从E.Drechsel法的以钨酸钠和磷酸氢二钠为原料,改为以活性粉状白钨酸^([1,2])为原料,与磷酸直接反应,即成12-钨磷酸溶液。这样便可以免除Drechscl乙醚萃取法^([3,4])中大量盐酸的使用。在提纯时,把在Drechsel方法中所用的乙醚,改为沸点高的正丁醚,配合适当少量的盐酸,可以得到相应的(钅羊)盐油状物。并由于该(钅羊)盐安定度较差,用水反萃取即可使12-钨磷酸转入水溶液,经过浓缩即可得到12-钨磷酸晶体。回收的正丁醚,毋需蒸馏,可以反复使用。

The white powdery tungstic acid prepared according to previous reports^([1,2]) reacts directly with phosphoric acid solution to form a solution of 12-tungstophos-phoric acid with some other polytungstates.For purification, the solution was extracted with n-butyl ether under suitable addition of hydrochloric acid, so as to produce an oily layer which is not miscible with water and excessive n-butyl ether. The n-butyl ether layer was then stripped with water to obtain pure aqueous solution of 12-tungstophosphoric acid. On evaporation by heating, 12-tungstophosphoric acid gradually separated out as pure crystals.