View source for Aluminium chlorohydrate

{{Short description|Group of specific aluminium salts having the general formula AlnCl(3n-m)(OH)m}}
'''Aluminium chlorohydrate''' is a group of water-soluble,<ref>{{Cite web|title=Aluminum chlorohydrate|url=https://go.drugbank.com/drugs/DB11573|access-date=2021-01-10|website=go.drugbank.com}}</ref> specific aluminium [[Salt (chemistry)|salt]]s having the general formula {{chem2|Al_{''n''}Cl_{3''n''-''m''}(OH)_{''m''}|auto=1}}. It is used in cosmetics as an [[antiperspirant]] and as a coagulant in [[water purification]].

In water purification, this compound is preferred in some cases because of its high [[Electric charge|charge]], which makes it more effective at destabilizing and removing suspended materials than other aluminium salts such as [[aluminium sulfate]], [[aluminium chloride]] and various forms of polyaluminium chloride (PAC) and [[polyaluminium chlorosulfate]], in which the aluminium structure results in a lower net charge than aluminium chlorohydrate. Further, the high degree of neutralization of the [[Hydrochloric acid|HCl]] results in minimal impact on treated water pH when compared to other aluminium and iron salts.

==Uses==
Aluminium chlorohydrate is one of the most common active ingredients in commercial [[antiperspirant]]s.<ref>{{Cite journal|vauthors=Lukacs VA, Korting HC |title=[Antiperspirants and deodorants—ingredients and evaluation] |language=de |journal=Dermatosen in Beruf und Umwelt |volume=37 |issue=2 |pages=53–7 |year=1989 |pmid=2656175}}</ref> The variation most commonly used in deodorants and antiperspirants is {{chem2|Al2Cl(OH)5}} (dialuminium chloride pentahydroxide).

Aluminium chlorohydrate is also used as a [[Flocculation|coagulant]] in water and wastewater treatment processes to remove [[dissolved organic matter]] and [[colloid]]al particles present in suspension.

==Safety==
The U.S. [[Food and Drug Administration]] considers the use of aluminium chlorohydrate in antiperspirants to be safe and it is permitted in concentrations up to 25%.<ref>[https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?fr=350.10&SearchTerm=aluminum%20chlorohydrate Code of Federal Regulations Title 21] {{CodeFedReg|21|350|10}}</ref>

===Alzheimer's disease===
Studies have found only a negligible association between exposure to and long-term use of antiperspirants and [[Alzheimer's disease]].<ref>{{Cite journal|vauthors=Graves AB, White E, Koepsell TD, Reifler BV, van Belle G, Larson EB |title=The association between aluminium-containing products and Alzheimer's disease |journal=Journal of Clinical Epidemiology |volume=43 |issue=1 |pages=35–44 |year=1990 |pmid=2319278 |doi=10.1016/0895-4356(90)90053-R}}</ref> There is no adequate evidence that exposure to aluminium in antiperspirants leads to progressive dementia and Alzheimer's disease.<ref>{{Cite journal|author =Exley C |title=Does antiperspirant use increase the risk of aluminium-related disease, including Alzheimer's disease? |journal=Molecular Medicine Today |volume=4 |issue=3 |pages=107–9 |date=March 1998 |pmid=9575492 |doi=10.1016/S1357-4310(98)01209-X}}</ref>

Heather M. Snyder, the senior associate director of medical and scientific relations for the Alzheimer's Association, has stated, "There was a lot of research that looked at the link between Alzheimer's and aluminium, and there hasn't been any definitive evidence to suggest there is a link".<ref name=webmd>{{cite web | url = http://www.webmd.com/skin-beauty/features/antiperspirant-facts-safety?page=2 | title = Antiperspirant Safety: Should You Sweat It? | publisher = [[WebMD]]}}</ref>

===Breast cancer===
The International Journal of Fertility and Women's Medicine found no evidence that certain chemicals used in underarm cosmetics increase the risk of [[breast cancer]].<ref>{{Cite journal|last1=Gikas |first1=PD |last2=Mansfield |first2=L |last3=Mokbel |first3=K|title=Do underarm cosmetics cause breast cancer? |journal=Int. J. Fertil. Womens Med |volume=49 |issue=5 |pages=212–4 |year=2004 |pmid=15633477}}</ref> Ted S. Gansler, the director of medical content for the [[American Cancer Society]], stated "There is no convincing evidence that antiperspirant or deodorant use increases cancer risk".<ref name=webmd/>

However, there is continued concern over the use of aluminium chlorohydrate in cosmetics as the risk of toxic build up over time has not been ruled out.<ref>{{Cite web|url=https://www.breastcanceruk.org.uk/science-and-research/background-briefings/aluminium-salts/|title=Aluminium salts in antiperspirants {{!}} Breast Cancer UK|website=www.breastcanceruk.org.uk|access-date=2019-04-15|archive-date=2019-08-24|archive-url=https://web.archive.org/web/20190824081451/https://www.breastcanceruk.org.uk/science-and-research/background-briefings/aluminium-salts/|url-status=dead}}</ref> The [[Scientific Committee on Consumer Safety|Scientific Committee on Consumer Safety (SCCS)]] is currently designing a study to analyse the build up of aluminium chlorohydrate via dermal penetration to assess the risk of toxic build up.<ref>{{Cite web|url=https://ec.europa.eu/health/sites/health/files/scientific_committees/consumer_safety/docs/sccs2016_q_009.pdf|title=The safety of Aluminium in cosmetic Products|date=7 March 2017|website=Scientific Committee on Consumer Safety|archive-url=https://web.archive.org/web/20190415144208/https://ec.europa.eu/health/sites/health/files/scientific_committees/consumer_safety/docs/sccs2016_q_009.pdf|archive-date=15 April 2019|access-date=15 April 2019}}</ref>

==Structure==
Aluminium chlorohydrate is best described as an inorganic polymer and as such is difficult to structurally characterize. However, techniques such as [[gel permeation chromatography]], [[X-ray crystallography]] and <sup>27</sup>Al-[[Nuclear magnetic resonance|NMR]] have been used in research by various groups including that of Nazar<ref>{{Cite journal|doi=10.1021/ja993711 |vauthors=Rowsell J, Nazar LF |year=2000 |title=Speciation and Thermal Transformation in Alumina Sols: Structures of the Polyhydroxyoxoaluminum Cluster [Al<sub>30</sub>O<sub>8</sub>(OH)<sub>56</sub>(H<sub>2</sub>O)<sub>26</sub>]<sup>18+</sup> and Its δ-Keggin Moieté |journal=Journal of the American Chemical Society |volume=122 |issue=15 |pages=3777–8}}</ref> and Laden<ref>{{Cite book |first1=Karl |last1=Laden |first2=Carl B. |last2=Felger |title=Antiperspirants and deodorants |publisher=M. Dekker |location=New York |year=1988 |isbn=978-0-8247-7893-4 |url-access=registration |url=https://archive.org/details/antiperspirantsd0007unse}}{{Page needed|date=September 2010}}</ref> to show that the material is based on {{chem2|Al13}} units with a [[Keggin structure|Keggin ion]] structure and that this base unit then undergoes complex transformations to form larger poly-aluminum complexes.

==Synthesis==
Aluminium chlorohydrate can be commercially manufactured by reacting aluminium with [[hydrochloric acid]]. A number of aluminium-containing raw materials can be used, including [[aluminium]] [[metal]], [[alumina trihydrate]], [[aluminium chloride]], [[aluminium sulfate]] and combinations of these. The products can contain byproduct salts, such as [[sodium chloride|sodium]]/[[calcium chloride|calcium]]/[[magnesium chloride]] or [[sulfate]].<ref>{{Cite book|author =American National Standards Institute |year=1993 |title=AWWA standard for liquid poly aluminium chloride |location=[[Denver]] |publisher=[[American Water Works Association]] |oclc=31849037|author-link=American National Standards Institute}}</ref>

Because of the explosion hazard related to [[hydrogen]] produced by the reaction of aluminium with hydrochloric acid, the most common industrial practice is to prepare a solution of aluminium chlorohydrate (ACH) by reacting [[aluminium hydroxide]] with [[hydrochloric acid]]. The ACH product is reacted with aluminium ingots at 100&nbsp;°C using steam in an open mixing tank. The Al to ACH ratio and the time of reaction allowed determines the polymer form of the PAC ''n'' to ''m'' ratio.{{citation needed|date=October 2023}}

==See also==
* [[Aluminium chloride]]
* [[Aluminium hydroxide]]
* [[Deodorant]]
* [[Keggin structure]]

==References==
{{Reflist|2}}

{{Medicated dressings}}
{{Drugs for treatment of bone diseases}}

{{DEFAULTSORT:Aluminium Chlorohydrate}}
[[Category:Aluminium compounds]]
[[Category:Chlorides]]