六偏磷酸钠

六偏磷酸钠(SHMP)是磷酸钠的六聚体 (NaPO₃)₆。^[1] 商业上的六偏磷酸钠通常是聚合偏磷酸盐的混合物，六聚体是其中一种，通常是这个名称所指的化合物。它更正确的说法是聚偏磷酸钠。

目录编辑

1 用途编辑

SHMP用作螯合剂，并被广泛应用于各种行业中，包括食品添加剂（食品添加剂国际E代码E452i）。碳酸钠有时被添加到SHMP中以提高pH到8.0-8.6，使得一系列SHMP产品被用作水软化剂或洗涤剂。

六偏磷酸钠的一个重要用途是作为粘土基陶瓷制品生产中的悬浮剂。^[2]^[3]^[4]^[5] 它还被用作分解粘土和其他土壤类型的分散剂，以便进行土壤质地评价。^[6]

它被用作牙膏中的活性成分，作为抗污染和防牙垢的成分。^[7]

1.1 食品添加剂

作为食品添加剂，SHMP被用作乳化剂。人造枫糖浆、罐装牛奶、奶酪粉和蘸酱、人造奶酪、可打发糖霜、包装蛋清、烤牛肉、鱼片、果冻、冷冻甜点、沙拉酱、鲱鱼、早餐麦片、冰淇淋、啤酒、瓶装饮料及其他食品中都可能含有SHMP。^[8]^[9]^[10]

2 制备编辑

SHMP是通过加热磷酸二氢钠生成焦磷酸钠而制备的:

2 NaH₂PO₄→ Na₂H₂P₂O₇ + H₂O

随后，焦磷酸被加热以得到相应的六偏磷酸钠:

3 Na₂H₂P₂O₇ → (NaPO₃)₆ + 3 H₂O

接着是快速冷却。

3 反应编辑

SHMP在水溶液中水解，特别是在酸性条件下，生成三偏磷酸钠和正磷酸钠。^[11]

4 历史编辑

1849年德国化学家Theodor Fleitmann (1828-1904)命名了六偏磷酸(但被错误鉴定)。^[12]^[13] 到1956年，格兰汉姆盐(多磷酸钠)水解产物的色谱分析表明存在含有四个以上磷酸基团的环状阴离子；^[14] 这些发现在1961年得到证实。^[15] 1963年，德国化学家埃里希·希洛(Erich Thilo)和乌尔里希·施吕克(Ulrich Schülke)通过加热无水三偏磷酸钠成功制备了六偏磷酸钠。^[16]

参考文献

[1]
^Van Wazer, John R. Phosphorus and its compounds. New York : Interscience Publishers (1958).
[2]
^The Role Of Sodium Hexametaphosphate In The Dissolution Process Of Kaolinite And KaolinF. Andreola; E.Castellini; T.Manfredini; M.Romagnoli. Journal of the European Ceramic Society, Volume 24, Number 7, June 2004..
[3]
^Impact Of Dispersants On The Mechanical Strength Development Of Alumina-Spinel Self-Flowing Refractory Castables. Sasan Otroj, Mohammad Reza Nilforushan, Arash Daghighi, Reza Marzban. Ceramics – Silikáty 54 (3) 284–289 (2010).
[4]
^Effect Of Adding Sodium Hexametaphosphate Liquefier On Basic Properties Of Calcium Phosphate Cements. S. Hesaraki; A. Zamanian; F. Moztarzadeh. Journal of Biomedical Materials Research Part A. Vol. 88A, No. 2, 2009.
[5]
^Study Of Clay’s Mineralogy Effect On Rheological Behavior Of Ceramic Suspensions Using An Experimental Design. Afef Jmal Ayadi; Julien Soro; Amel Kamoun; Samir Baklouti. International Journal of Recent Research and Applied Studies 14 (2). February 2013..
[6]
^ASTM D422 – 63(2007) Standard Test Method for Particle-Size Analysis of Soils..
[7]
^Crest Pro-Health Frequently Asked Questions.
[8]
^"Ingredient Results - Sodium Hexametaphosphate"..
[9]
^"Food Additives & Ingredients - Food Additive Status List"..
[10]
^"CFR - Code of Federal Regulations Title 21"..
[11]
^Van Wazer, John (1958). Phosphorus and its Compounds. New York: Interscience Publishers. Retrieved 7 April 2015..
[12]
^Fleitmann, Th. (1849). "Ueber die verschiedenen Metaphosphorsäuren und zwei neue Säuren derselben Verbindungsproportion" [On various metaphosphoric acids and two new acids of the same compound proportion]. Annalen der Physik und Chemie. 2nd series (in German). 78: 233–260, 338–366.CS1 maint: Unrecognized language (link) On p. 249, Fleitmann coined the name Hexametaphosphorsäure (hexametaphosphoric acid)..
[13]
^Griffith, E.J.; Buxton, R.L. (1965). "The preparation and properties of the twelve-membered ring hexametaphosphate anion". Inorganic Chemistry. 4 (4): 549–551. ; see p. 549..
[14]
^Van Wazer, J. R.; Kroupa, E. Karl (1956). "Existence of ring phosphates higher than tetrametaphosphate". Journal of the American Chemical Society. 78 (8): 1772..
[15]
^(Thilo & Schülke, 1963a), p. 1175..
[16]
^See: Thilo, E.; Schülke, U. (1963a). "Darstellung des echten Natrium-hexametaphosphates Na6[P6O18]" [Preparation of true sodium hexametaphosphate Na6[P6O18]]. Angewandte Chemie (in German). 75 (23): 1175–1176.CS1 maint: Unrecognized language (link) Thilo, E.; Schülke, U. (1963b). "Preparation of true sodium hexametaphosphate Na6[P6O18]". Angewandte Chemie International Edition. 2 (12): 742..

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