関: Alhydrogel、aluminum hydroxide

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2016/04/22 19:19:25」(JST)

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Aluminium hydroxide, Al(OH)₃, is found in nature as the mineral gibbsite (also known as hydrargillite) and its three much rarer polymorphs: bayerite, doyleite and nordstrandite. Closely related are aluminium oxide hydroxide, AlO(OH), and aluminium oxide (or alumina), Al₂O₃. These compounds together are the major components of the aluminium ore bauxite. Freshly precipitated aluminium hydroxide forms gels, which are the basis for the application of aluminium salts as flocculants in water purification. This gel crystallizes with time. Aluminium hydroxide gels can be dehydrated (e.g. using water-miscible non-aqueous solvents like ethanol) to form an amorphous aluminium hydroxide powder, which is readily soluble in acids. Aluminium hydroxide powder which has been heated to an elevated temperature under carefully controlled conditions is known as activated alumina and is used as a desiccant, as an adsorbent in gas purification, as a Claus catalyst support for water purification, and as an adsorbent for the catalyst during the manufacture of polyethylene by the Sclairtech process.

Nomenclature

The naming for the different forms of aluminium hydroxide is ambiguous and there is no universal standard. All four polymorphs have a chemical composition of aluminium trihydroxide (an aluminium atom attached to three hydroxide groups).^[3]

Gibbsite is also known as hydrargillite, named after the Greek words for water (hydra) and clay (argylles). The first compound named hydrargillite was thought to be aluminium hydroxide, but was later found to be aluminium phosphate; despite this, both gibbsite and hydrargillite are used to refer to the same polymorphism of aluminium hydroxide, with gibbsite used most commonly in the United States and hydrargillite used more often in Europe. In 1930 it was referred to as α-alumina trihydrate to contrast it with bayerite which was called β-alumina trihydrate (the alpha and beta designations were used to differentiate the more- and less-common forms respectively). In 1957 a symposium on alumina nomenclature attempted to develop a universal standard, resulting in gibbsite being designated γ-Al(OH)₃ and bayerite becoming α-Al(OH)₃ and nordstrandite being designated Al(OH)₃. Based on their crystallographic properties, a suggested nomenclature and designation is for gibbsite to be α-Al(OH)₃, bayerite to be designated β-Al(OH)₃ and both nordstrandite and doyleite are designated Al(OH)₃. Under this designation, the α and β prefixes refer to hexagonal, close-packed structures and altered or dehydrated polymorphisms respectively, with no differentiation between nordstrandite and doyleite.^[3]

Properties

Gibbsite has a typical metal hydroxide structure with hydrogen bonds. It is built up of double layers of hydroxyl groups with aluminium ions occupying two-thirds of the octahedral holes between the two layers.^[4]

Aluminium hydroxide is amphoteric. It dissolves in acid, forming [Al(H₂O)₆]³⁺ (hexaaquaaluminium) or its hydrolysis products. It also dissolves in strong alkali, forming [Al(OH)₄]⁻ (tetrahydroxidoaluminate).

Polymorphism

Four polymorphs of aluminium hydroxide exist, all based on the common combination of one aluminium atom and three hydroxide molecules into different crystalline arrangements that determine the appearance and properties of the compound. The four combinations are:^[3]

Gibbsite
Bayerite
Nordstrandite
Doyleite

All polymorphs are composed of layers of octahedral aluminium hydroxide units with the aluminium atom in the centre and the hydroxyl groups on the sides, with hydrogen bonds holding the layers together. The polymorphisms vary in how the layers stack together, with the arrangements of the molecules and layers determined by the acidity, presence of ions (including salt) and the surface of the minerals the substance forms on. Under most conditions gibbsite is the most chemically stable form of aluminium hydroxide. All forms of Al(OH)₃ crystals are hexagonal.^[3]

Production

Virtually all the aluminium hydroxide used commercially is manufactured by the Bayer process^[5] which involves dissolving bauxite in sodium hydroxide at temperatures up to 270 °C (518 °F). The waste solid, bauxite tailings, is removed and aluminium hydroxide is precipitated from the remaining solution of sodium aluminate. This aluminium hydroxide can be converted to aluminium oxide or alumina by calcination.

The residue or bauxite tailings, which is mostly iron oxide, is highly caustic due to residual sodium hydroxide. It was historically stored in lagoons; this led to the Ajka alumina plant accident in 2010 in Hungary, where a dam burst led to the drowning of nine people. An additional 122 sought treatment for chemical burns. The mud contaminated 40 square kilometers of land and reached the Danube. While the mud was considered non-toxic due to low levels of heavy metals, it had a very high pH of 13.^[6]

Uses

Annual production is some 100 million tonnes,^{[citation needed]} over 90% of which is converted to aluminium oxide^{[citation needed]} (alumina) that is used in the manufacture of aluminium metal.^{[citation needed]}

The major other uses of aluminium hydroxide is as a feedstock for the manufacture of other aluminium compounds: specialty calcined aluminas, aluminium sulfate, polyaluminium chloride, aluminium chloride, zeolites, sodium aluminate, activated alumina, aluminium nitrate.^{[citation needed]}

Fire retardant

Aluminium hydroxide also finds use as a fire retardant filler for polymer applications in a similar way to magnesium hydroxide and mixtures of huntite and hydromagnesite.^[7]^[8]^[9]^[10]^[11] It decomposes at about 180 °C (356 °F), absorbing a considerable amount of heat in the process and giving off water vapour. In addition to behaving as a fire retardant, it is very effective as a smoke suppressant in a wide range of polymers, most especially in polyesters, acrylics, ethylene vinyl acetate, epoxies, PVC and rubber.

Pharmaceutical

Under the generic name algeldrate, aluminium hydroxide is used as an antacid. Brand names include Alu-Cap, Aludrox, Gaviscon or Pepsamar. It reacts with excess acid in the stomach, reducing the acidity of the stomach content,^[12] which may relieve the symptoms of ulcers, heartburn or dyspepsia. It can however cause constipation and is therefore often used with magnesium hydroxide or magnesium carbonate, which have counterbalancing laxative effects. This compound is also used to control phosphate (phosphorus) levels in the blood of people suffering from kidney failure.

Precipitated aluminium hydroxide is included as an adjuvant in some vaccines (e.g. anthrax vaccine). One of the well-known brands of aluminium hydroxide adjuvant is Alhydrogel, made by Sergeant Adjuvants.^[13] Since it absorbs protein well, it also functions to stabilize vaccines by preventing the proteins in the vaccine from precipitating or sticking to the walls of the container during storage. Aluminium hydroxide is sometimes mistakenly called "alum", which properly refers to aluminium potassium sulfate.

Vaccine formulations containing aluminium hydroxide stimulate the immune system by inducing the release of uric acid, an immunological danger signal. This strongly attracts certain types of monocytes which differentiate into dendritic cells. The dendritic cells pick up the antigen, carry it to lymph nodes, and stimulate T cells and B cells.^[14] It appears to contribute to induction of a good Th2 response, so is useful for immunizing against pathogens that are blocked by antibodies. However, it has little capacity to stimulate cellular (Th1) immune responses, important for protection against many pathogens,^[15] nor is it useful when the antigen is peptide-based.^[16]

Potential adverse effects

In the 1960s and 1970s it was speculated that aluminium was related to various neurological disorders including Alzheimer's disease.^[17]^[18] Since then, multiple epidemiological studies have found no connection between exposure to aluminium and neurological disorders.^[19]^[20]^[21]

References

^ http://www.ktf-split.hr/periodni/en/abc/kpt.html
^ Zumdahl, Steven S. (2009). Chemical Principles 6th Ed. Houghton Mifflin Company. ISBN 0-618-94690-X.
^ ^a ^b ^c ^d Karamalidis, AK; Dzombak DA (2010). Surface Complexation Modeling: Gibbsite. John Wiley & Sons. pp. 15–17. ISBN 0-470-58768-7.
^ Wells, A.F. (1975), Structural Inorganic Chemistry (4th ed.), Oxford: Clarendon Press
^ Hind, AR; Bhargava SK; Grocott SC (1999). "The Surface Chemistry of Bayer Process Solids: A Review". Colloids Surf Physiochem Eng Aspects 146: 359–74.
^ "Hungary Battles to Stem Torrent of Toxic Sludge". BBC News Website. 5 October 2010.
^ Hollingbery, LA; Hull TR (2010). "The Fire Retardant Behaviour of Huntite and Hydromagnesite - A Review". Polymer Degradation and Stability 95: 2213–2225. doi:10.1016/j.polymdegradstab.2010.08.019.
^ Hollingbery, LA; Hull TR (2010). "The Thermal Decomposition of Huntite and Hydromagnesite - A Review". Thermochimica Acta 509: 1–11. doi:10.1016/j.tca.2010.06.012.
^ Hollingbery, LA; Hull TR (2012). "The Fire Retardant Effects of Huntite in Natural Mixtures with Hydromagnesite". Polymer Degradation and Stability 97: 504–512. doi:10.1016/j.polymdegradstab.2012.01.024.
^ Hollingbery, LA; Hull TR (2012). "The Thermal Decomposition of Natural Mixtures of Huntite and Hydromagnesite". Thermochimica Acta 528: 45–52. doi:10.1016/j.tca.2011.11.002.
^ Hull, TR; Witkowski A; Hollingbery LA (2011). "Fire Retardant Action of Mineral Fillers". Polymer Degradation and Stability 96: 1462–1469. doi:10.1016/j.polymdegradstab.2011.05.006.
^ Galbraith, A; Bullock, S; Manias, E. Hunt, B. & Richards, A. (1999). Fundamentals of pharmacology: a text for nurses and health professionals. Harlow: Pearson. p. 482.
^ http://alhydrogelusa.com/
^ Kool, M; Soullié T; van Nimwegen M; Willart MA; Muskens F; Jung S; Hoogsteden HC; Hammad H; Lambrecht BN (2008-03-24). "T-helper 1 and T-helper 2 adjuvants induce distinct differences in the magnitude, quality and kinetics of the early inflammatory response at the site of injection". J Exp Med 205 (4): 869–82. doi:10.1111/j.1365-2567.2009.03164.x. PMC: 2807488. PMID 18362170.
^ Petrovsky N, Aguilar JC. (2004). "Vaccine adjuvants: current state and future trends". Immunol Cell Biol. 82 (5): 488–96. doi:10.1111/j.0818-9641.2004.01272.x. PMID 15479434.
^ Cranage, MP; Robinson A (2003). Robinson A; Hudson MJ; Cranage MP, ed. Vaccine Protocols - Volume 87 of Methods in Molecular Medicine Biomed Protocols (2nd ed.). Springer. pp. 176. ISBN 1-59259-399-2.
^ "Alzheimer's Myth's". Alzheimer's Association. Retrieved 2012-07-29.
^ Khan, A (2008-09-01). "Aluminium and Alzheimer's disease". Alzheimer's Society. Retrieved 2012-03-08.
^ Rondeau V (2002). "A review of epidemiologic studies on aluminum and silica in relation to Alzheimer's disease and associated disorders". Rev Environ Health 17 (2): 107–21. doi:10.1515/REVEH.2002.17.2.107. PMID 12222737.
^ Martyn CN, Coggon DN, Inskip H, Lacey RF, Young WF (May 1997). "Aluminum concentrations in drinking water and risk of Alzheimer's disease". Epidemiology 8 (3): 281–6. doi:10.1097/00001648-199705000-00009. PMID 9115023.
^ Graves AB, Rosner D, Echeverria D, Mortimer JA, Larson EB (September 1998). "Occupational exposures to solvents and aluminium and estimated risk of Alzheimer's disease". Occup Environ Med 55 (9): 627–33. doi:10.1136/oem.55.9.627. PMC: 1757634. PMID 9861186.

External links

International Chemical Safety Card 0373
"Some properties of aluminum hydroxide precipitated in the presence of clays", Soil Research Institute, R C Turner, Department of Agriculture, Ottawa
Effect of aging on properties of polynuclear hydroxyaluminum cations
A second species of polynuclear hydroxyaluminum cation, its formation and some of its properties

English Journal

Coagulation of methylated arsenic from drinking water: Influence of methyl substitution.

Hu C1, Chen Q2, Liu H2, Qu J2.
Journal of hazardous materials.J Hazard Mater.2015 Aug 15;293:97-104. doi: 10.1016/j.jhazmat.2015.03.055. Epub 2015 Mar 26.
Methylated arsenic can be found in virtually all earth surface environments. So far, however, little information has been collected regarding their removal by coagulation. In this study, the removal of monomethylarsenate (MMA) and dimethylarsenate (DMA) from drinking water by coagulation was investi
PMID 25855566

Safety and immunogenicity of a parenterally administered rotavirus VP8 subunit vaccine in healthy adults.

Fix AD1, Harro C2, McNeal M3, Dally L4, Flores J5, Robertson G6, Boslego JW7, Cryz S8.
Vaccine.Vaccine.2015 Jul 17;33(31):3766-72. doi: 10.1016/j.vaccine.2015.05.024. Epub 2015 Jun 8.
BACKGROUND: The P2-VP8 subunit vaccine for the prevention of rotavirus gastroenteritis is comprised of a truncated VP8 subunit protein from the rotavirus Wa strain (G1[P8]) fused to the tetanus toxin P2 epitope, and adsorbed on aluminum hydroxide for intramuscular administration.METHODS: Three group
PMID 26065919

Trichomonas vaginalis Infection Induces Vaginal CD4+ T-Cell Infiltration in a Mouse Model: A Vaccine Strategy to Reduce Vaginal Infection and HIV Transmission.

Smith JD1, Garber GE1.
The Journal of infectious diseases.J Infect Dis.2015 Jul 15;212(2):285-93. doi: 10.1093/infdis/jiv036. Epub 2015 Jan 23.
BACKGROUND: Complications related to the diagnosis and treatment of Trichomonas vaginalis infection, as well as the association between T. vaginalis infection and increased transmission of and susceptibility to human immunodeficiency virus, highlight the need for alternative interventions. We tested
PMID 25616405

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★リンクテーブル★

リンク元	「アルゲルドラート」「Alhydrogel」

「アルゲルドラート」

Aluminium hydroxide
Names
	Preferred IUPAC name Aluminium hydroxide
	Systematic IUPAC name Aluminium(3+) trioxidanide
	Other names Aluminic acid; Aluminic hydroxide; Aluminium(III) hydroxide; Aluminium hydroxide; Hydrated alumina; Orthoaluminic acid
Identifiers
CAS Number	21645-51-2
ChEBI	CHEBI:33130
ChEMBL	ChEMBL1200706
ChemSpider	8351587
Jmol 3D model	Interactive image
PubChem	10176082
RTECS number	BD0940000
UNII	5QB0T2IUN0
	InChI InChI=1S/Al.3H2O/h;31H2/q+3;;;/p-3 Key: WNROFYMDJYEPJX-UHFFFAOYSA-K; A02AB02 (WHO) (algeldrate) ; InChI=1/Al.3H2O/h;31H2/q+3;;;/p-3 Key: WNROFYMDJYEPJX-DFZHHIFOAJ ;
	SMILES [OH-].[OH-].[OH-].[Al+3] ;
Properties
Chemical formula	Al(OH)3
Molar mass	78.00 g/mol
Appearance	White amorphous powder
Density	2.42 g/cm3, solid
Melting point	300 °C (572 °F; 573 K)
Solubility in water	0.0001 g/100 mL (20 °C)
Solubility product (Ksp)	3×10−34
Solubility	soluble in acids, alkalis, HCl, H2SO4
Acidity (pKa)	>7
Thermochemistry
Std enthalpy of; formation (ΔfHo298)	−1277 kJ·mol−1
Pharmacology
ATC code	A02AB01 (WHO)
Hazards
Safety data sheet	External MSDS
EU classification (DSD)	Irritant (I) Xi
R-phrases	R36 R37 R38
S-phrases	S26 S36
NFPA 704	0 1 0
Flash point	Non-flammable
Related compounds
Other anions	None
Related compounds	Sodium oxide,; aluminium oxide hydroxide
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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	Infobox references

　　[★]

英: algeldrate
関: 水酸化アルミニウム、アルハイドロゲル

「Alhydrogel」

　　[★]

アルハイドロゲル

関: algeldrate、aluminum hydroxide

[1] ttp://www.ktf-split.hr/periodni/en/abc/kpt.html

[2] Zumdahl, Steven S. (2009). Chemical Principles 6th Ed. Houghton Mifflin Company. ISBN 0-618-94690-X.

[Karamalidis-3] Karamalidis, AK; Dzombak DA (2010). Surface Complexation Modeling: Gibbsite. John Wiley & Sons. pp. 15–17. ISBN 0-470-58768-7.

[4] Wells, A.F. (1975), Structural Inorganic Chemistry (4th ed.), Oxford: Clarendon Press

[5] Hind, AR; Bhargava SK; Grocott SC (1999). "The Surface Chemistry of Bayer Process Solids: A Review". Colloids Surf Physiochem Eng Aspects 146: 359–74.

[6] "Hungary Battles to Stem Torrent of Toxic Sludge". BBC News Website. 5 October 2010.

[7] Hollingbery, LA; Hull TR (2010). "The Fire Retardant Behaviour of Huntite and Hydromagnesite - A Review". Polymer Degradation and Stability 95: 2213–2225. doi:10.1016/j.polymdegradstab.2010.08.019.

[8] Hollingbery, LA; Hull TR (2010). "The Thermal Decomposition of Huntite and Hydromagnesite - A Review". Thermochimica Acta 509: 1–11. doi:10.1016/j.tca.2010.06.012.

[9] Hollingbery, LA; Hull TR (2012). "The Fire Retardant Effects of Huntite in Natural Mixtures with Hydromagnesite". Polymer Degradation and Stability 97: 504–512. doi:10.1016/j.polymdegradstab.2012.01.024.

[10] Hollingbery, LA; Hull TR (2012). "The Thermal Decomposition of Natural Mixtures of Huntite and Hydromagnesite". Thermochimica Acta 528: 45–52. doi:10.1016/j.tca.2011.11.002.

[11] Hull, TR; Witkowski A; Hollingbery LA (2011). "Fire Retardant Action of Mineral Fillers". Polymer Degradation and Stability 96: 1462–1469. doi:10.1016/j.polymdegradstab.2011.05.006.

[12] Galbraith, A; Bullock, S; Manias, E. Hunt, B. & Richards, A. (1999). Fundamentals of pharmacology: a text for nurses and health professionals. Harlow: Pearson. p. 482.

[13] ttp://alhydrogelusa.com/

[14] Kool, M; Soullié T; van Nimwegen M; Willart MA; Muskens F; Jung S; Hoogsteden HC; Hammad H; Lambrecht BN (2008-03-24). "T-helper 1 and T-helper 2 adjuvants induce distinct differences in the magnitude, quality and kinetics of the early inflammatory response at the site of injection". J Exp Med 205 (4): 869–82. doi:10.1111/j.1365-2567.2009.03164.x. PMC: 2807488. PMID 18362170.

[15] Petrovsky N, Aguilar JC. (2004). "Vaccine adjuvants: current state and future trends". Immunol Cell Biol. 82 (5): 488–96. doi:10.1111/j.0818-9641.2004.01272.x. PMID 15479434.

[Cranage-16] Cranage, MP; Robinson A (2003). Robinson A; Hudson MJ; Cranage MP, ed. Vaccine Protocols - Volume 87 of Methods in Molecular Medicine Biomed Protocols (2nd ed.). Springer. pp. 176. ISBN 1-59259-399-2.

[ALZ-17] "Alzheimer's Myth's". Alzheimer's Association. Retrieved 2012-07-29.

[AS-18] Khan, A (2008-09-01). "Aluminium and Alzheimer's disease". Alzheimer's Society. Retrieved 2012-03-08.

[19] Rondeau V (2002). "A review of epidemiologic studies on aluminum and silica in relation to Alzheimer's disease and associated disorders". Rev Environ Health 17 (2): 107–21. doi:10.1515/REVEH.2002.17.2.107. PMID 12222737.

[20] Martyn CN, Coggon DN, Inskip H, Lacey RF, Young WF (May 1997). "Aluminum concentrations in drinking water and risk of Alzheimer's disease". Epidemiology 8 (3): 281–6. doi:10.1097/00001648-199705000-00009. PMID 9115023.

[21] Graves AB, Rosner D, Echeverria D, Mortimer JA, Larson EB (September 1998). "Occupational exposures to solvents and aluminium and estimated risk of Alzheimer's disease". Occup Environ Med 55 (9): 627–33. doi:10.1136/oem.55.9.627. PMC: 1757634. PMID 9861186.

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案内

algeldrate