氯胺

氯胺
英文名	Chloramine
别名	氯代氨; 一氯代氨
识别
CAS号	10599-90-3
PubChem	25423
ChemSpider	23735
SMILES	ClN;
InChI	1/ClH2N/c1-2/h2H2;
InChIKey	QDHHCQZDFGDHMP-UHFFFAOYAS
性质
化学式	NH2Cl
摩尔质量	51.48 g·mol⁻¹
外观	無色
熔点	−66 °C
溶解性（其他溶劑）	可溶
相关物质
相关化学品	三氯化氮
	若非注明，所有数据均出自标准状态（25 ℃，100 kPa）下。

氯胺，又稱氯代氨，是一种無機化合物，为氨中一个（一氯代氨）、二个（二氯代氨）或者三个（三氯化氮）氢原子被氯取代之后得到之氨衍生物。氯胺一词也指一系列化学式為 R₂NCl 及 RNCl₂ 的有机化合物。

一氯代氨的化学式是NH₂Cl，为不稳定的无色液体，熔点−66 °C（−87 °F），通常以水溶液的形式储存和使用。该溶液有时被用作消毒劑。由於其不穩定性，其沸点無法测量。^[1]

水处理

氯胺可用于水的消毒，与氯气相比较为温和，与次氯酸盐相比更加稳定。

饮用水消毒

低浓度的NH₂Cl在市政供水系统中作为二级消毒剂。其应用与日俱增，并逐渐取代氯气（在水处理过程中被称为游离氯）。NH₂Cl远比游离氯稳定，且不易在水中被浪费。相对比起游离氯，其与有机化合物反应形成有机氯化合物的趋势较小，但依旧存在；这些有机氯化合物包括氯仿和四氯化碳；这些物质在已被确定为致癌物质，美国国家环境保护局从1979年起开始管控饮用水中的这些有机氯化合物的浓度。^[2]

与此同时，一些不受管制的副产品有可能造成更大的健康风险。^[3]以氯胺净水亦可能增加饮用水中铅含量，尤其是对于老旧住宅而言。暴露于此种高铅浓度的条件下，或导致血液中铅含量增加，并可能造成重大健康风险。^[4]

游泳池消毒

在游泳池中，氯胺通过游离氯与诸如尿液、汗液、皮肤细胞等物质当中的有机物反应而生成。相对比起游离氯，其杀菌效果较差；而且若不能适当地控制，其对于游泳者的眼睛亦会具有更强的刺激性。氯胺也是游泳池中独特的“氯”的味道的来源。^[5]^[6]一些为私人游泳池设计的测试工具无法区分游离氯与氯胺，这或导致游泳池中的氯胺浓度不适当。^[7]亦有证据显示，暴露于氯胺会引起游泳者的呼吸道问题，包括哮喘。^[8]对于竞技游泳运动员，呼吸道问题常见而普遍。^[9]

安全性

基于过往数据，美国国家环境保护局（EPA）制定的饮用水水质标准限制公众供水系统中氯胺含量不得多于 4 ppm。为了达到EPA规定的卤化消毒副产物（英语：disinfection by-product）限量标准，许多公用事业部门正在把净化方式从氯化转向氯胺化（英语：chloramination）。虽然氯胺化产生的卤化消毒副产物较少，但可产生更高浓度的未受管控的含碘副产物及N-亚硝基二甲胺；^[10]^[11] 此二者皆已被证明具有遗传毒性^[11]。

用作血液透析^[12]、养殖、水耕栽培^[13]及自酿啤酒时，应当设法除去水中的氯胺。在用作透析时，若氯胺进入血液中，可能会导致溶血性贫血。^[12] 若水耕栽培的培养液中混入氯胺，则会延缓植物的生长。^[13]

制备

氯胺可以透過氨與次氯酸根反应制得：NH₃ + ClO⁻ → NH₂Cl + OH⁻ ^[14]。此反应必须在弱碱性 (pH 8.5–11)的环境下进行。进行反应的氯化剂是次氯酸，其通过氢离子和次氯酸根反应生成，而后参与氨取代产生氢氧根的亲核取代反应。此反应在 pH 约为8时反应最快；若 pH 过高，则次氯酸浓度过小；若 pH 过低，则氨形成铵根，而后者不发生上述反应。氯胺可通过真空蒸馏，并将蒸汽通过碳酸钾（干燥剂）浓缩。氯胺也可以通过乙醚萃取。

气态氯胺亦可通过氨气和氯气反应得到（过程中用氮气稀释）：

2 NH₃(g) + Cl₂(g) ⇌ NH₂Cl(g) + NH₄Cl(s)

纯氯胺可将氟胺吹过氯化钙得到：

2 NH₂F + CaCl₂ → 2 NH₂Cl + CaF₂

參考文獻

^ Lawrence, Stephen A. Amines: Synthesis, Properties and Applications. Cambridge University Press. 2004: 172 [2018-05-16]. ISBN 9780521782845. （原始内容存档于2018-04-06）（英语）.
^ 存档副本 (PDF). [2014-06-02]. （原始内容存档 (PDF)于2008-11-02）.
^ Stuart W. Krasner. The formation and control of emerging disinfection by-products of health concern 367 (1904). Philosophical Transactions of the Royal Society: 4077–95. 2009-10-13. doi:10.1098/rsta.2009.0108. （原始内容存档于2015-10-27）.
^ Marie Lynn Miranda; et al. Changes in Blood Lead Levels Associated with Use of Chloramines in Water Treatment Systems. Environmental Health Perspectives. February 2007, 115 (2): 221–5. PMC 1817676 . PMID 17384768. doi:10.1289/ehp.9432.
^ Donegan, Fran J.; David Short. Pools and Spas. Upper Saddle River, New Jersey: Creative Homeowner. 2011. ISBN 978-1-58011-533-9.
^ Controlling Chloramines in Indoor Swimming Pools. NSW Government. [2013-02-15]. （原始内容存档于2011-04-03）.
^ Hale, Chris. Pool Service Information. 2016-04-20 [2016-04-22]. （原始内容存档于2016-04-05）.
^ Bougault, Valérie; et al. The Respiratory Health of Swimmers. Sports Medicine. 2009, 39 (4): 295–312. doi:10.2165/00007256-200939040-00003. （原始内容存档于2011-06-05）.
^ The determinants of prevalence of health complaints among young competitive swimmers. International Archives of Occupational and Environmental Health. 2006-10-01, 80 (1): 32–39. doi:10.1007/s00420-006-0100-0. ^{[永久失效連結]}
^ Krasner, Stuart W.; Weinberg, Howard S.; Richardson, Susan D.; Pastor, Salvador J.; Chinn, Russell; Sclimenti, Michael J.; Onstad, Gretchen D.; Thruston, Alfred D. Occurrence of a New Generation of Disinfection Byproducts. Environmental Science & Technology. 2006, 40 (23): 7175–7185. doi:10.1021/es060353j.
^ ^11.0 ^11.1 Richardson, Susan D.; Plewa, Michael J.; Wagner, Elizabeth D.; Schoeny, Rita; DeMarini, David M. Occurrence, genotoxicity, and carcinogenicity of regulated and emerging disinfection by-products in drinking water: A review and roadmap for research. Mutation Research/Reviews in Mutation Research. 2007, 636 (1–3): 178–242. PMID 17980649. doi:10.1016/j.mrrev.2007.09.001.
^ ^12.0 ^12.1 Hakim, Nadey. Artificial Organs. London: Springer-Verlag. 2009: 51 [2014-06-14]. ISBN 9781848822818. Water that contains chloramine is safe for people to drink, bathe, and cook in because the digestive process neutralizes it. Chloramine can, however, easily harm patients if it enters the blood stream during the dialysis process causing hemolytic anemia.
^ ^13.0 ^13.1 Date, S.; Terabayashi, S.; Kobayashi, Y.; Fujime, Y., Effects of chloramines concentration in nutrient solution and exposure time on plant growth in hydroponically cultured lettuce, Scientia Horticulturae, 2005, 103 (3): 257–265, doi:10.1016/j.scienta.2004.06.019
^ Fair, G. M., J. C. Morris, S. L. Chang, I. Weil, and R. P. Burden. 1948. The behavior of chlorine as a water disinfectant. J. Am. Water Works Assoc. 40:1051-1061.

[1] Lawrence, Stephen A. Amines: Synthesis, Properties and Applications. Cambridge University Press. 2004: 172 [2018-05-16]. ISBN 9780521782845. （原始内容存档于2018-04-06）（英语）.

[2] 存档副本 (PDF). [2014-06-02]. （原始内容存档 (PDF)于2008-11-02）.

[3] Stuart W. Krasner. The formation and control of emerging disinfection by-products of health concern 367 (1904). Philosophical Transactions of the Royal Society: 4077–95. 2009-10-13. doi:10.1098/rsta.2009.0108. （原始内容存档于2015-10-27）.

[4] Marie Lynn Miranda; et al. Changes in Blood Lead Levels Associated with Use of Chloramines in Water Treatment Systems. Environmental Health Perspectives. February 2007, 115 (2): 221–5. PMC 1817676 . PMID 17384768. doi:10.1289/ehp.9432.

[5] Donegan, Fran J.; David Short. Pools and Spas. Upper Saddle River, New Jersey: Creative Homeowner. 2011. ISBN 978-1-58011-533-9.

[6] Controlling Chloramines in Indoor Swimming Pools. NSW Government. [2013-02-15]. （原始内容存档于2011-04-03）.

[7] Hale, Chris. Pool Service Information. 2016-04-20 [2016-04-22]. （原始内容存档于2016-04-05）.

[8] Bougault, Valérie; et al. The Respiratory Health of Swimmers. Sports Medicine. 2009, 39 (4): 295–312. doi:10.2165/00007256-200939040-00003. （原始内容存档于2011-06-05）.

[9] The determinants of prevalence of health complaints among young competitive swimmers. International Archives of Occupational and Environmental Health. 2006-10-01, 80 (1): 32–39. doi:10.1007/s00420-006-0100-0. ^{[永久失效連結]}

[10] Krasner, Stuart W.; Weinberg, Howard S.; Richardson, Susan D.; Pastor, Salvador J.; Chinn, Russell; Sclimenti, Michael J.; Onstad, Gretchen D.; Thruston, Alfred D. Occurrence of a New Generation of Disinfection Byproducts. Environmental Science & Technology. 2006, 40 (23): 7175–7185. doi:10.1021/es060353j.

[Richardson07-11] 11.0 ^11.1 Richardson, Susan D.; Plewa, Michael J.; Wagner, Elizabeth D.; Schoeny, Rita; DeMarini, David M. Occurrence, genotoxicity, and carcinogenicity of regulated and emerging disinfection by-products in drinking water: A review and roadmap for research. Mutation Research/Reviews in Mutation Research. 2007, 636 (1–3): 178–242. PMID 17980649. doi:10.1016/j.mrrev.2007.09.001.

[dialysis-12] 12.0 ^12.1 Hakim, Nadey. Artificial Organs. London: Springer-Verlag. 2009: 51 [2014-06-14]. ISBN 9781848822818. Water that contains chloramine is safe for people to drink, bathe, and cook in because the digestive process neutralizes it. Chloramine can, however, easily harm patients if it enters the blood stream during the dialysis process causing hemolytic anemia.

[hydroponic-13] 13.0 ^13.1 Date, S.; Terabayashi, S.; Kobayashi, Y.; Fujime, Y., Effects of chloramines concentration in nutrient solution and exposure time on plant growth in hydroponically cultured lettuce, Scientia Horticulturae, 2005, 103 (3): 257–265, doi:10.1016/j.scienta.2004.06.019

[ref29-14] Fair, G. M., J. C. Morris, S. L. Chang, I. Weil, and R. P. Burden. 1948. The behavior of chlorine as a water disinfectant. J. Am. Water Works Assoc. 40:1051-1061.

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