瓦耳登还原器

瓦尔登还原器（Walden reductor）是一种银还原柱，它能将水溶液中的金属离子还原成较低价的氧化态。例如:将UO₂²⁺还原成U⁴⁺，^[1]此还原柱由乔治.H.瓦尔登（George H. Walden）与他的博士生赛文.M.爱德蒙斯（Sylvan M. Edmonds）于哥伦比亚大学共同研发。^[2]

制备及使用

将一段铜线浸在硝酸银溶液中，金属银迅速在铜线上形成树枝状结晶析出：

Cu + 2Ag⁺ —> Cu²⁺ + 2Ag

然后把银结晶从铜线上取下，并用纯水冲洗除去多馀的硝酸铜和硝酸银后放进一细小的玻璃管柱中。^[2]^[3]
这个装置类似柱层析，使用时，将欲还原的金属离子水溶液从顶端倒入，使其顺著管柱自然流下，还原反应随之进行，溶液到达管柱下端时，还原反应接近100%完成。^[2]^[3]

应用

此方法可以用来在化学分析时获得较低价态的化学物质，或者制备少量化合物。^[1]^[2]^[3]

参见

其他还原器

琼斯还原器

其他氧化剂

参考资料

^ ^1.0 ^1.1 Mendham, J; Denney, R.C; Barnes, J.D.; Thomas, M. (2000). Vogel's Textbook of Quantitative Chemical Analysis (6th ed.). Pearson Education Ltd. ISBN 0-582-22628-7.
^ ^2.0 ^2.1 ^2.2 ^2.3 Walden, George H.; Hammett, Louis P.; Edmonds, Sylvan M. (1934). "Phenathroline-Ferrous Ion. III. A Silver Reductor. The Direct Determination of Iron in the Presence of Vanadium". Journal of the American Chemical Society 56 (2): 350. doi:10.1021/ja01317a023
^ ^3.0 ^3.1 ^3.2 Smith, G. F.; Cagle, F. W. (1948). "Preparation of Silver for Use in Walden Silver Reductor". Analytical Chemistry 20 (2): 183. doi:10.1021/ac60014a024

进一步阅读

Birnbaum, Nathan; Edmonds, Sylvan M. New applications of the silver reductor. Industrial & Engineering Chemistry Analytical Edition. 1940, 12 (3): 155–157. ISSN 0096-4484. doi:10.1021/ac50143a013.
Edmonds, Sylvan M.; Birnbaum, Nathan. Microdetermination of iron with the silver reductor. Industrial & Engineering Chemistry Analytical Edition. 1940, 12 (1): 60–61. ISSN 0096-4484. doi:10.1021/ac50141a024.
Huffman, Eugene H. Regeneration of Walden silver reductor. Industrial & Engineering Chemistry Analytical Edition. 1946, 18 (4): 278. doi:10.1021/i560152a023.
Khan, M.A. Salam; Stephen, W.I. An improved silver reagent for use in the Walden silver reductor. The Analyst. 1968, 93 (1102): 26. Bibcode:1968Ana....93...26K. ISSN 0003-2654. doi:10.1039/an9689300026.
Pantani, Francesco. The use of the silver reductor in bromide solutions. Analytica Chimica Acta. 1964, 31: 121. doi:10.1016/S0003-2670(00)88792-9.

[one-1] 1.0 ^1.1 Mendham, J; Denney, R.C; Barnes, J.D.; Thomas, M. (2000). Vogel's Textbook of Quantitative Chemical Analysis (6th ed.). Pearson Education Ltd. ISBN 0-582-22628-7.

[two-2] 2.0 ^2.1 ^2.2 ^2.3 Walden, George H.; Hammett, Louis P.; Edmonds, Sylvan M. (1934). "Phenathroline-Ferrous Ion. III. A Silver Reductor. The Direct Determination of Iron in the Presence of Vanadium". Journal of the American Chemical Society 56 (2): 350. doi:10.1021/ja01317a023

[three-3] 3.0 ^3.1 ^3.2 Smith, G. F.; Cagle, F. W. (1948). "Preparation of Silver for Use in Walden Silver Reductor". Analytical Chemistry 20 (2): 183. doi:10.1021/ac60014a024

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