7784-24-9

Basic information

• Product Name: Aluminium potassium sulfate dodecahydrate
• Synonyms: POTASSIUM ALUMINIUM SULFATE 12-WATER;POTASSIUM ALUMINIUM SULFATE DODECAHYDRATE;POTASSIUM ALUM;POTASSIUM ALUMINUM SULFATE DODECAHYDRATE;POTASSIUM ALUM SULFATE, DODECAHYDRATE;POTASSIUM ALUM DODECAHYDRATE;POTASSIUM AMMONIUM SULFATE;aluminumpotassiumdisulfatedodecahydrate
• CAS NO: 7784-24-9
• Molecular Formula: AlH24KO20S2
• Molecular Weight: 474.39
• EINECS: 233-141-3
• Mol File: 7784-24-9.mol
• Article Data: 0

Chemical Properties

• Melting Point: 92 °C(lit.)
• Boiling Point: 330 °C at 760 mmHg
• Appearance: White/Solid
• Density: 1.757 g/mL at 25 °C(lit.)
• Storage Temp.: Store at RT.
• Solubility: H2O: soluble0.5M, clear, colorless
• Water Solubility: 140 G/L (20 ºC)
• Stability: Stable. Incompatible with steel, aluminium, copper, zinc, bases, strong oxidizing agents.
• Merck: 14,360
• CAS DataBase Reference: Aluminium potassium sulfate dodecahydrate(CAS DataBase Reference)
• NIST Chemistry Reference: Aluminium potassium sulfate dodecahydrate(7784-24-9)
• EPA Substance Registry System: Aluminium potassium sulfate dodecahydrate(7784-24-9)

Safety Data

• Hazard Codes: Xn,Xi
• Statements: 36/38-22-36/37/38-21/22
• Safety Statements: 22-24/25-37/39-26-36-20-13-2
• WGK Germany: 3
• RTECS: WS5690000
• TSCA: Yes
• Hazardous Substances Data: 7784-24-9(Hazardous Substances Data)

Usage

Chemical Properties

Different sources of media describe the Chemical Properties of 7784-24-9 differently. You can refer to the following data:
1. white to colourless crystals
2. Aluminum is the most commonly available element in homes and workplaces. Aluminum is readily available for human ingestion through the use of food additives, antacids, buffered aspirin, astringents, nasal sprays, and antiperspirants; from drinking water; from automobile exhaust and tobacco smoke; and from using aluminum foil, aluminum cookware, cans, ceramics, and fi reworks. Workers who are at risk for toxicity are those in refi neries, foundries and also welders and grinders.

Uses

Different sources of media describe the Uses of 7784-24-9 differently. You can refer to the following data:
1. potassium alum (alum) is a cosmetic astringent.
2. Aluminium potassium sulfate dodecahydrate is a white crystal that is soluble in water. It is made by roasting alunite in a furnace and then harvesting the product by crystallization. Aluminium potassium sulfate dodecahydrate was used to harden gelatin emulsions by introduction, by bathing the exposed plates prior to development, or by use in the fixing bath. Mixed with citric or other acids, it was also used as a clearing bath to remove developer stains in negatives.
3. Buffer; floccculating reagent.

Definition

Different sources of media describe the Definition of 7784-24-9 differently. You can refer to the following data:
1. ChEBI: A hydrate resulting from the the formal combination of anhydrous potassium aluminium sulfate with 12 mol eq. of water.
2. A group of double salts withthe formula A2SO4.B2(SO4)3.24H2O,where A is a monovalent metal and Ba trivalent metal. The original examplecontains potassium and aluminium(called potash alum orsimply alum); its formula is oftenwritten AlK(SO4)2.12H2O (aluminiumpotassium sulphate-12-water). Ammoniumalum is AlNH4(SO4)2.12H2O,chrome alum is KCr(SO4)2.12H2O, etc.The alums are isomorphous and canbe made by dissolving equivalentamounts of the two salts in waterand recrystallizing.

General Description

Aluminum potassium sulfate dodecahydrate is an inorganic sulfate salt of aluminum and potassium. Linear growth rates of (100), (111) and (110) faces of its crystals have been investigated.

Health Hazard

Prolonged periods of exposure to aluminum and dust cause symptoms of toxicity that include, but are not limited to, coughing, wheezing, shortness of breath, memory loss, learning diffi culty, loss of coordination, disorientation, mental confusion, colic, heartburn, fl atulence, and headaches. Chronic exposures to alumina dust cause irritation to the eyes,

Purification Methods

Crystallise it from weak aqueous H2SO4 (ca 0.5mL/g). Its solubility (%) in H2O is 5.7 (0o), 12.0 (20o) and 136.9 (100o).

Precautions

Aminocarb decomposes on heating and produces toxic fumes, irritating fumes, and oxides of nitrogen. During handling of aminocarb workers should wear protective clothing, gloves, face shield, breathing protection and avoid open flames.

InChI:InChI=1/Al.K.H2O4S.12H2O/c;;1-5(2,3)4;;;;;;;;;;;;/h;;(H2,1,2,3,4);12*1H2/q+3;+1;;;;;;;;;;;;;/p-2

Synthetic route

potassium alum (7784-24-9) + 2K(1+)*S(18)O4(2-)=K2S(18)O4 → KAl(S(18)O4)2*12H2O, α (123724-20-9)

Conditions	Yield
In water byproducts: KAl(S(16)O(18)O3)2*12H2O, KAl(S(16)O4)2*12H2O; addn. of 10% of 98% O-18 enriched K2SO4 to normal alum, evapn. to dryness; impurities detected by Raman;