【摘要】 本工作肯定,水在漂白粉的稳定性问题中具有极其重要的作用.漂白粉和漂粉精样品在0.1毫米汞柱的蒸气压下可脱去的水称为可脱水.在90°下八小时后样品中有效氯量占原有效氯量的百分数称为其稳定度.稳定度测值指出,样品的可脱水率从0%递增时,其稳定度则从100%递减至0%.根据吸水率-蒸气压图等数据,样品的可脱水主要分布在物相Ca（OCl）₂·3H₂O（S）和CaCl₂·6H₂O（S）中,而在90°下,全部可脱水则集中至前一物相.样品有效氯成分的分解主要在Ca（OCl）₂·3H₂O（S）中,而在Ca（OCl）₂（S）中分解很少.稳定度的数据指出,在90°下,样品有效氯分解率与其中可脱水率成正比,从而亦与其中物相Ca（OCl）₂·3H₂O（S）的含率成正比. 根据上述,作者并从生产实践的意义讨论了漂白粉的稳定性问题.更多还原

【Abstract】 In the present investigation, water in bleaching powder was found to play a leading role in determining the stability of the latter. In order to compare the stability of various samples of bleaching powder, we determined the content of the available chlorine before and after a sample kept in a small glass-stoppered tube at 90℃ for 8 hours. The ratio of residual to the original content of available chlorine when expressed in percentage is defined as the index of stability.The samples of bleaching powder and raw calcium hypochlorite investigated in our work contain-ed in the main the following components: Ca（Ocl）₂（S）, Ca（OCl）₂·3H₂O（S）, CaCl₂·6H₂O（S）and CaCl₂·Ca（OH）₂·H₂O（S）. When bleaching powder or raw calcium hypochlorite was thoroughly dried under a vapor pressure of 0.1 mm. Hg at 25°, two of the components were dehydrated according to the following reactions （Figure 5）: Ca（OCl）₂·3H₂O（S） = Ca（OCl）₂（S） + 3H₂O（～5mm. Hg） CaCl₂·6H₂O（S）=CaCl₂·H₂O（S） + 5H₂O（～1.0 mm. Hg） and the index of stability attained 100% （Figures 6 and 7）. Water which can be removed from a sample under the above conditions is defined as removable water. By the control of amount of the removable water in a sample, the index of stability can be made to vary between 0 to 100%.If we take the percentage of the available chlorine decomposed in an hour at 90 as the rate of decomposition （D %/hr.）, the latter seemed to vary linearly with the amount of removable water （W %） （Figure 8）. When the samples were heated in a stoppered tube to 90° from 25°, the removable water probably redistributed according to the following scheme: xCa（OCl）₂（S） + y Ca（OCl）₂·3H₂O（S） + z CaCl₂·6H₂O（S） 25° xCa（OCl）₂（S） + （y + （5z）/3） Ca（OCl）₂·3H₂O（S） + z CaCl₂·H₂O（S） 90° Inasmuch as the thoroughly dried samples did not decompose considerably even at 90°, the decomposition of OCl^- seemed to take place almost exclusively in the phase Ca（OCl）₂·3H₂O（S）. The linear relationship of D vers. W indicated that the decomposition rate of a sample varied linearly with its content of the component Ca（OCl）₂·3H₂O（S） at 90°. In the light of the above results, an explanation was proposed to account for the decomposition of bleaching powder under the conditions of storage.更多还原