为了保持药品的干燥或对制得的气体进行干燥,必须使用干燥剂。常用的干燥剂有三类:一类为酸性干燥剂,有浓硫酸、五氧化二磷、硅胶等;第二类为碱性干燥剂,有固体烧碱、石灰和碱石灰(氢氧化钠和氢氧化钙的混合物)等;第三类是中性干燥剂,如无水氯化钙、无水硫酸镁等。常用干燥剂的性能和用途如下: In order to keep the medicine dry or to dry the produced gas, a desiccant must be used. There are three commonly used desiccants: one is an acidic desiccant, concentrated sulfuric acid, phosphorus pentoxide, silica gel, etc.; the second is an alkaline desiccant, a solid caustic soda, lime and soda lime (sodium hydroxide and hydroxide A mixture of calcium), etc.; the third type is a neutral desiccant, such as anhydrous calcium chloride, anhydrous magnesium sulfate, and the like. The properties and uses of commonly used desiccants are as follows: