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目前三氯化磷生产厂大都用碘量法测定含量,此法操作简便、稳定、快速,其理论依据是三氯化磷水解生成亚磷酸,再用碘氧化成正磷酸,用碘的消耗量来换算出三氯化磷的含量。 PCl_3+3H_2O→H_3PO_3+3HCl H_3PO_3+I_2+H_2O→H_3PO_4+2HI 反应中生成的HCl和HI使介质成酸性,不利于反应的进行,必须调整pH值降低介质酸度,对此大多数厂采用氢氧化铵加硼酸来调整(10%NH_4OH170毫升加20克H_3BO_3溶解后稀
At present, most of the phosphorus trichloride production plant with iodometric method for the determination of content, this method is simple, stable and fast, the theoretical basis is the hydrolysis of phosphorus trichloride to generate phosphorous acid, and then oxidized to orthophosphoric acid iodine, with iodine consumption Conversion of phosphorus trichloride content. HCl and HI generated in the reaction of PCl_3 + 3H_2O → H_3PO_3 + 3HCl H_3PO_3 + I_2 + H_2O → H_3PO_4 + 2HI make the medium acidic and not conducive to the progress of the reaction. The pH value must be adjusted to reduce the acidity of the medium. For most plants, hydrogenation Ammonium plus boric acid to adjust (10% NH_4OH170 ml plus 20 g H_3BO_3 dissolved dilute