From Wikipedia, the miễn phí encyclopedia
Bạn đang xem: al(oh)3
|Preferred IUPAC name
|Systematic IUPAC name
3D model (JSmol)
CompTox Dashboard (EPA)
|Molar mass||78.003 g·mol−1|
|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)|
Solubility product (Ksp)
|Solubility||soluble in acids and alkalis|
Std enthalpy of
|P261, P264, P271, P280, P304+P340, P305+P351+P338, P312, P337+P313|
|NFPA 704 (fire diamond)|
Xem thêm: tờ tự kiểm học sinh
|Lethal dose or concentration (LD, LC):|
LD50 (median dose)
|>5000 mg/kg (rat, oral)|
|Safety data sheet (SDS)||External MSDS|
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
verify (what is ?)
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. Aluminium hydroxide is amphoteric, i.e., it has both basic and acidic properties. Closely related are aluminium oxide hydroxide, AlO(OH), and aluminium oxide or alumina (Al2O3), the latter of which is also amphoteric. These compounds together are the major components of the aluminium ore bauxite. Aluminium hydroxide also forms a gelatinous precipitate in water.
Al(OH)3 is built up of double layers of hydroxyl groups with aluminium ions occupying two-thirds of the octahedral holes between the two layers. Four polymorphs are recognized. All feature layers of octahedral aluminium hydroxide units, with hydrogen bonds between the layers. The polymorphs differ in terms of the stacking of the layers. All forms of Al(OH)3 crystals are hexagonal[disputed – discuss]:
- gibbsite is also known as γ-Al(OH)3  or α-Al(OH)3
- bayerite is also known as α-Al(OH)3 or β-alumina trihydrate
- nordstrandite is also known as Al(OH)3
Hydrargillite, once thought lớn be aluminium hydroxide, is an aluminium phosphate. Nonetheless, both gibbsite and hydrargillite refer lớn the same polymorphism of aluminium hydroxide, with gibbsite used most commonly in the United States and hydrargillite used more often in Europe. Hydrargillite is named after the Greek words for water (hydra) and clay (argylles).
Aluminium hydroxide is amphoteric. In acid, it acts as a Brønsted–Lowry base. It neutralizes the acid, yielding a salt:
- 3 HCl + Al(OH)3 → AlCl3 + 3 H2O
In bases, it acts as a Lewis acid by binding hydroxide ions:
- Al(OH)3 + OH− → [Al(OH)4]−
Virtually all the aluminium hydroxide used commercially is manufactured by the Bayer process which involves dissolving bauxite in sodium hydroxide at temperatures up lớn 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 lớn aluminium oxide or alumina by calcination.
The residue or bauxite tailings, which is mostly iron oxide, is highly caustic due lớn residual sodium hydroxide. It was historically stored in lagoons; this led lớn the Ajka alumina plant accident in 2010 in Hungary, where a dam bursting led lớn the drowning of nine people. An additional 122 sought treatment for chemical burns. The mud contaminated 40 square kilometres (15 sq mi) of land and reached the Danube. While the mud was considered non-toxic due lớn low levels of heavy metals, the associated slurry had a pH of 13.
Fire retardant filler
Aluminium hydroxide also finds use as a fire retardant filler for polymer applications. It is selected for these applications because it is colorless (like most polymers), inexpensive, and has good fire retardant properties. Magnesium hydroxide and mixtures of huntite and hydromagnesite are used similarly. It decomposes at about 180 °C (356 °F), absorbing a considerable amount of heat in the process and giving off water vapour. In addition lớn 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, polyvinyl chloride (PVC) and rubber.
Precursor lớn Al compounds
Aluminium hydroxide is a feedstock for the manufacture of other aluminium compounds: calcined aluminas, aluminium sulfate, polyaluminium chloride, aluminium chloride, zeolites, sodium aluminate, activated alumina, and aluminium nitrate.
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 lượt thích ethanol) lớn khuông an amorphous aluminium hydroxide powder, which is readily soluble in acids. Heating converts it lớn activated aluminas, which are used as desiccants, adsorbent in gas purification, and catalyst supports.
Under the generic name "algeldrate", aluminium hydroxide is used as an antacid in humans and animals (mainly cats and dogs). It is preferred over other alternatives such as sodium bicarbonate because Al(OH)3, being insoluble, does not increase the pH of stomach above 7 and hence, does not trigger secretion of excess acid by the stomach. Brand names include Alu-Cap, Aludrox, Gaviscon or Pepsamar. It reacts with excess acid in the stomach, reducing the acidity of the stomach nội dung, which may relieve the symptoms of ulcers, heartburn or dyspepsia. Such products can cause constipation, because the aluminium ions inhibit the contractions of smooth muscle cells in the gastrointestinal tract, slowing peristalsis and lengthening the time needed for stool lớn pass through the colon. Some such products are formulated lớn minimize such effects through the inclusion of equal concentrations of magnesium hydroxide or magnesium carbonate, which have counterbalancing laxative effects.
This compound is also used lớn control hyperphosphatemia (elevated phosphate, or phosphorus, levels in the blood) in people and animals suffering from kidney failure. Normally, the kidneys filter excess phosphate out from the blood, but kidney failure can cause phosphate lớn accumulate. The aluminium salt, when ingested, binds lớn phosphate in the intestines and reduce the amount of phosphorus that can be absorbed.
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 Brenntag Biosector.[full citation needed][dead link] Since it absorbs protein well, it also functions lớn stabilize vaccines by preventing the proteins in the vaccine from precipitating or sticking lớn the walls of the container during storage. Aluminium hydroxide is sometimes called "alum", a term generally reserved for one of several sulfates.
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 lớn lymph nodes, and stimulate T cells and B cells. It appears lớn contribute lớn induction of a good Th2 response, sánh is useful for immunizing against pathogens that are blocked by antibodies. However, it has little capacity lớn stimulate cellular (Th1) immune responses, important for protection against many pathogens, nor is it useful when the antigen is peptide-based.
In the 1960s and 1970s it was speculated that aluminium was related lớn various neurological disorders, including Alzheimer's disease. Since then, multiple epidemiological studies have found no connection between exposure lớn environmental or swallowed aluminium and neurological disorders, though injected aluminium was not looked at in these studies.
Neural disorders were found in experiments on mice motivated by Gulf War illness (GWI). Aluminium hydroxide injected in doses equivalent lớn those administered lớn the United States military, showed increased reactive astrocytes, increased apoptosis of motor neurons and microglial proliferation within the spinal cord and cortex.
Xem thêm: tính bằng cách thuận tiện lớp 4
- ^ For solubility product: "Solubility product constants". Archived from the original on 15 June 2012. Retrieved 17 May 2012.
- ^ For isoelectric point: Gayer, K. H.; Thompson, L. C.; Zajicek, O. T. (September 1958). "The solubility of aluminum hydroxide in acidic and basic truyền thông at 25 ?c". Canadian Journal of Chemistry. 36 (9): 1268–1271. doi:10.1139/v58-184. ISSN 0008-4042.
- ^ Zumdahl, Steven S. (2009). Chemical Principles (6th ed.). Houghton Mifflin Company. ISBN 978-0-618-94690-7.
- ^ Black, Ronald A.; Hill, D. Ashley (15 June 2003). "Over-the-Counter Medications in Pregnancy". American Family Physician. 67 (12): 2517–2524. ISSN 0002-838X. PMID 12825840. Retrieved 1 July 2017.
- ^ Wells, A. F. (1975), Structural Inorganic Chemistry (4th ed.), Oxford: Clarendon Press
- ^ a b Evans, K. A. (1993). "Properties and uses of aluminium oxides and aluminium hydroxides". In A. J. Downs (ed.). Chemistry of aluminium, gallium, indium, and thallium (1st ed.). London; New York: Blackie Academic & Professional. ISBN 9780751401035.
- ^ Karamalidis, A. K.; Dzombak D. A. (2010). Surface Complexation Modeling: Gibbsite. John Wiley & Sons. pp. 15–17. ISBN 978-0-470-58768-3.
- ^ a b c Wefers, Karl; Misra, Chanakya (1987). Oxides and hydroxides of aluminum. Alcoa Research Laboratories. p. 2. OCLC 894928306.
- ^ a b Boundless (26 July 2016). "Basic and Amphoteric Hydroxides". Boundless Chemistry. Archived from the original on 22 August 2017. Retrieved 2 July 2017.
- ^ Hind, AR; Bhargava SK; Grocott SC (1999). "The Surface Chemistry of Bayer Process Solids: A Review". Colloids Surf Physiochem Eng Aspects. 146 (1–3): 359–74. doi:10.1016/S0927-7757(98)00798-5.
- ^ "Hungary Battles lớn Stem Torrent of Toxic Sludge". BBC News Website. 5 October 2010.
- ^ a b Hudson, L. Keith; Misra, Chanakya; Perrotta, Anthony J.; Wefers, Karl; Williams, F. S. (2000). "Aluminum Oxide". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a01_557.
- ^ Hollingbery, LA; Hull TR (2010). "The Fire Retardant Behaviour of Huntite and Hydromagnesite - A Review" (PDF). Polymer Degradation and Stability. 95 (12): 2213–2225. doi:10.1016/j.polymdegradstab.2010.08.019.
- ^ Hollingbery, LA; Hull TR (2010). "The Thermal Decomposition of Huntite and Hydromagnesite - A Review" (PDF). Thermochimica Acta. 509 (1–2): 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" (PDF). Polymer Degradation and Stability. 97 (4): 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" (PDF). Thermochimica Acta. 528: 45–52. doi:10.1016/j.tca.2011.11.002.
- ^ Hull, TR; Witkowski A; Hollingbery LA (2011). "Fire Retardant kích hoạt of Mineral Fillers" (PDF). Polymer Degradation and Stability. 96 (8): 1462–1469. doi:10.1016/j.polymdegradstab.2011.05.006. S2CID 96208830.
- ^ Huber Engineered Materials. "Huber Non-Halogen Fire Retardant Additives" (PDF). Retrieved 3 July 2017.
- ^ 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.
- ^ Papich, Mark G. (2007). "Aluminum Hydroxide and Aluminum Carbonate". Saunders Handbook of Veterinary Drugs (2nd ed.). St. Louis, Mo: Saunders/Elsevier. pp. 15–16. ISBN 9781416028888.
- ^ Washington, Neena (2 August 1991). Antacids and Anti Reflux Agents. Boca Raton, FL: CRC Press. p. 10. ISBN 978-0-8493-5444-1.
- ^ Bill, Robert L. (1 September 2016). Clinical Pharmacology and Therapeutics for Veterinary Technicians - E-Book. Elsevier Health Sciences. p. 105. ISBN 9780323444026.
- ^ Plumb, Donald C. (2011). "Aluminum Hydroxide". Plumb's Veterinary Drug Handbook (7th ed.). Stockholm, Wisconsin; Ames, Iowa: Wiley. pp. 36–37. ISBN 9780470959640.
- ^ Lifelearn Inc. (1 November 2010). "Aluminum Hydroxide". Know Your Pet. Retrieved 30 June 2017.
- ^ "About Brenntag Biosector - Brenntag". brenntag.com. Retrieved 19 April 2018.
- ^ Kool, M; Soullié T; khẩn khoản Nimwegen M; Willart MA; Muskens F; Jung S; Hoogsteden HC; Hammad H; Lambrecht BN (24 March 2008). "Alum adjuvant boosts adaptive immunity by inducing uric acid and activating inflammatory dendritic cells". J Exp Med. 205 (4): 869–82. doi:10.1084/jem.20071087. PMC 2807488. PMID 18362170.
- ^ Petrovsky N, Aguilar JC (2004). "Vaccine adjuvants: current state and future trends". Immunology & Cell Biology. 82 (5): 488–96. doi:10.1111/j.0818-9641.2004.01272.x. PMID 15479434. S2CID 154670.
- ^ Cranage, MP; Robinson A (2003). Robinson A; Hudson MJ; Cranage MP (eds.). Vaccine Protocols - Volume 87 of Methods in Molecular Medicine Biomed Protocols (2nd ed.). Springer. p. 176. ISBN 978-1-59259-399-6.
- ^ "Alzheimer's Myth's". Alzheimer's Association. Retrieved 29 July 2012.
- ^ Khan, A (1 September 2008). "Aluminium and Alzheimer's disease". Alzheimer's Society. Archived from the original on 11 March 2012. Retrieved 8 March 2012.
- ^ Rondeau V (2002). "A review of epidemiologic studies on aluminum and silica in relation lớn Alzheimer's disease and associated disorders". Rev Environ Health. 17 (2): 107–21. doi:10.1515/REVEH.2002.17.2.107. PMC 4764671. PMID 12222737.
- ^ Martyn công nhân, Coggon Doanh Nghiệp, 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. JSTOR 3702254. PMID 9115023. S2CID 32190038.
- ^ Graves AB, Rosner D, Echeverria D, Mortimer JA, Larson EB (September 1998). "Occupational exposures lớn 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.
- ^ Shaw, Christopher A.; Petrik, Michael S. (November 2009). "Aluminum hydroxide injections lead lớn motor deficits and motor neuron degeneration". Journal of Inorganic Biochemistry. 103 (11): 1555–1562. doi:10.1016/j.jinorgbio.2009.05.019. ISSN 1873-3344. PMC 2819810. PMID 19740540.
- 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[permanent dead link]
- Effect of ageing on properties of polynuclear hydroxyaluminium cations
- A second species of polynuclear hydroxyaluminium cation, its formation and some of its properties