Alum Potassium

The compounds of greatest importance are aluminum oxide, the sulfate, and the soluble sulfate with potassium (alum). The oxide, alumina, occurs naturally as ruby, sapphire, corundum, and emery, and is used in glassmaking and refractories. Synthetic ruby and sapphire are used in lasers for producing coherent light. 

Potassium Aluminum Sulfate. Potassium aluminum sulfate [7784-24-9]. KAl(SO 12H20, is a white, astringent crystal known as potassium alum, ordinary alum, or potash alum. Its formula weight is 474.39 mp 92.5 °C sp gr 1.75 and solubiUty 11.4 g per 100 mL H2O at 20°C (8). It is soluble in dilute acid and insoluble in alcohol. It dehydrates at about 200 °C to porous desiccated potassium alum [10043-67-1], KAl(SO dried or burnt alum, which has a formula weight of 258.20. 

Potassium alum is manufactured by treating bauxite with sulfuric acid and then potassium sulfate. Alternatively, aluminum sulfate is reacted with potassium sulfate, or the mineral alum stone, alunite, can be calciaed and leached with sulfuric acid. Alunite is a basic potassium aluminum sulfate... 

Potassium alum, which also occurs naturally as the mineral kalinite [7784-24-9], KAl(SO 2 12H20, sp gr 1.75, is used ia tanning skins, as a mordant ia dyeiag, and ia the pharmaceutical and cosmetic iadustries (see Pharmaceuticals Cosmetics). It is used as a styptic pencil and as a hardening agent and set accelerator for cement and plaster. The ACGIH threshold limit value TWA is 2 mgAl/m (1 ). 

Isomerization and Hydrogenolysis. lsomeri2ation of propylene oxide to propionaldehyde and acetone occurs over a variety of catalysts, eg, pumice, siUca gel, sodium or potassium alum, and 2eohtes (80,81). Stronger acid catalysts favor acetone over propionaldehyde (81). AHyl alcohol yields of 90% are obtained from use of a supported lithium phosphate catalyst (82). 

Astringents are designed to dry the skin, denature skin proteins, and tighten or reduce the size of pore openings on the skin surface. These products can have antimicrobial effects and are frequendy buffered to lower the pH of skin. They are perfumed, hydro-alcohoHc solutions of weak acids, such as tannic acid or potassium alum, and various plant extracts, such as bitch leaf extract. The alcohol is not only a suitable solvent but also helps remove excess sebum and soil from the skin. After-shave lotions generally function as astringents. 

Doki, N., Kubota, N., Sato, A., Yokota, M., Hamada, O. and Masumi, F., 1999. Scaleup experiments on seeded batch cooling crystallization of potassium alum. American Institution of Chemical Engineers Journal, 45(12), 2527-2533. 

Kaiium, n. potassium, -alatm, m. potassium alum, -azetat, n. potassium acetate, -bor-fluorid, n. potassium fluoborate. -brech-weinstein, m. antimonyl potassium tartrate, tartar emetic. 

Alum Borax Natron Iron vitriol Mineral Mineral Mineral Mineral or synthetic Sulfate of aluminum and other metals (e.g., potassium alum) Hydrated sodium borate Natural mixture sodium carbonate and sodium bicarbonate Hydrated iron sulfate... 

Theory The solution of potassium alum is heated with an excess of disodium edetate to ensure complete formation of aluminium-edetate complex. Hexamine serves as a buffer thereby stabilizing the pH between 5 and 6, the ideal pH for the titration of the disodium edetate not required by the A1 with 0.05 M lead nitrate employing xylenol orange as indicator. The various reactions involved may be represented by the following equations ... 

Procedure Weigh accurately 1.7 g of potassium alum and dissolve it in sufficient DW in a flask. Heat the contents of flask over a water-bath for 10 minutes to allow completion of complexation and cool to ambient temperature. Now, add 1 g hexamine to act as buffer and titrate with 0.05 M lead nitrate employing 0.4 ml of xylenol orange solution as an indicator. The colour shall change from that of the indicator (yellow at the pH of the titration) to the corresponding reddish purple, the colour of the lead complex of the indicator. Each ml of 0.05 M disodium edetate is equivalent to 0.02372 g of KA1(S04)2, 12H20. 

Theory The percentage of A1 in potassium alum can be determined volumetrically by complexometric titration (see Chapter 9). 

Potassium sulfate is used in fertilizers as a source of potassium and sulfur, both of which are essential elements for plant growth. Either in simple form or as a double salt with magnesium sulfate, potassium sulfate is one of the most widely consumed potassium salts in agricultural apphcations. It is preferred over potassium chloride for certain types of crops such as, tobacco, citrus, and other chloride—sensitive crops. Some other applications include making gypsum cements to make potassium alum in the analysis of Kjeldahl nitrogen and in medicine. 

The alteration in sensitiveness of a suspension to electrolytes by the addition of a non-electrolyte was first noted by Blake (Amer. Jour, of Soi. xvi. 439, 1903) who observed that the quantity of potassium alum necessary to convert a red gold into a violet form had to be increased on the addition of ether to the suspension the liminal concentration without ether was found to be 00035 whilst in an aqueous solution saturated with ether 00151 equivalent per litre were required. 

In 1821 Arfwedson published a supplementary note to his lithium research (11), in which he stated that the salt which he had previously reported as lithium acid sulfate must be the normal sulfate and that the double sulfate he had at first taken for lithium alum was really potassium alum resulting from a trace of potassium in his alumina. 

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