水热法制备Keggin型磷钨杂多酸

Hydrothermal synthesis of Keggin type phosphotungstic acid

采用水热法制备具有Keggin结构的12-磷钨酸,分析酸化pH值对12-磷钨酸制备过程的影响。研究发现,钨酸钠溶液的酸化pH值是制备12-磷钨酸的关键步骤,决定了产物是否具有Keggin结构。当第一步盐酸酸化pH值为6~7时,135℃下通过水热反应,WO_4^(2-)生成12聚体的仲钨酸B,仲钨酸B具有很高的活性,在pH值为2.0~2.3时下与磷酸反应生成12-磷钨酸。与传统方法相比,该合成方法避免了乙醚和大量高浓度强酸的使用,大大提高了制备过程的安全性并降低了对设备的腐蚀性。

To synthesize Keggin type 12-phosphotungstic acid,this paper used hydrothermal synthesis method,and analyzed the acidification p H values influence during the process. The results showed that acidification p H value of sodium tungstate solution is the key step of 12-phosphotungstic acid preparation. And it determines whether the product has a Keggin structure. When acidification pH is at 6 ~ 7 range,through hydrothermal reaction under135℃,WO_4^(2-) changes into Secondary Tungstic Acid B,which has a high activity,and reacts with H_3PO_4 to synthesize 12-phosphotungstic acid at 2. 0 ~ 2. 3 pH range. Compared with traditional method,this method can avoid using ether and large amount of strong acid. It may largely improve the security of the process and decrease corrosion on equipments.