Aluminium chlorohydrate

Basic aluminium chloride
IUPAC name	aluminium chloride dihydroxide
Identifiers
InChI	InChI=1/Al.ClH.2H2O/h;1H;2*1H2/q+3;;;/p-3
InChIKey	YCLAMANSVUJYPT-DFZHHIFOAH
Standard InChI	InChI=1S/Al.ClH.2H2O/h;1H;2*1H2/q+3;;;/p-3
Standard InChIKey	YCLAMANSVUJYPT-UHFFFAOYSA-K
CAS number	[1327-41-9]
EC number	215-477-2
ATC code	M05BX02
ChemSpider	8373134
Properties
Chemical formula	AlCl(OH)2
Molar mass	174.45 g/mol
Hazards
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)

Dialuminium chloride pentahydroxide
IUPAC name	dialuminium chloride pentahydroxide
Identifiers
InChI	InChI=1/2Al.ClH.5H2O/h;;1H;5*1H2/q2*+3;;;;;;/p-6
InChIKey	ZGRQKCWNBYXGOB-CYFPFDDLAZ
Standard InChI	InChI=1S/2Al.ClH.5H2O/h;;1H;5*1H2/q2*+3;;;;;;/p-6
Standard InChIKey	ZGRQKCWNBYXGOB-UHFFFAOYSA-H
CAS number	[12042-91-0]
EC number	234-933-1
ChemSpider	8329776
Properties
Chemical formula	Al2Cl(OH)5
Molar mass	174.45 g/mol
Hazards
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)

Aluminium chlorohydrate is a group of salts having the general formula Al_nCl_(3n-m)(OH)_m. It is used in deodorants and antiperspirants and as a flocculant in water purification.

In water purification, where it is usually called polyaluminium chloride, this compound is preferred in some cases because the pH value can be varied according to the exact values chosen for the subscripts _n and _m in the pattern formula. Although many variations are used, an especially important combination is Al₁₂Cl₁₂(OH)₂₄. The actual pH correlates to the formula m/(3n).

Structure

Aluminium chlorohydrate is best described as an inorganic polymer and as such is difficult to structurally characterise. However, techniques such as Gel permeation chromatography, X-ray crystallography and ²⁷Al-NMR have been used in research by various groups including that of Nazar and Laden to show that the material is based on Al₁₃ units with a Keggin ion structure and that this base unit then undergoes complex transformations to form larger poly-aluminium 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 by-product salts, such as sodium/calcium/magnesium chloride or sulfate.

Because of the potential explosive hazard of mixing aluminium metal 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 °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.

Safety

The variation most commonly used in deodorants and antiperspirants is Al₂Cl(OH)₅. There is no scientific evidence supporting widespread rumors that aluminium salts in deodorants can cause Alzheimer's disease or breast cancer. Amongst others, research published in the Journal of the National Cancer Institute found no evidence whatsoever that these compounds increase the risk of breast cancer. However, aluminium is a neurotoxin that alters the function of the blood-brain barrier, and it is one of the few abundant elements that appears to have no beneficial function to living cells.

Synonyms

• Aluminium hydroxychloride
• Aluminium chlorhydroxide
• Aluminium chloride basic
• Aluminium chlorohydrol
• Polyaluminium chloride

See also

• Aluminium chloride
• Aluminium hydroxide
• Keggin structure

External links

• D09AA08, M05BX02
• NIOSH Pocket Guide to Chemical Hazards 0024
• IPCS Environmental Health Criteria 194: Aluminium

References

Template:Medicated dressings Template:Drugs for treatment of bone diseases