Sodium-calcium alloy

Silicon Alkali carbonates, calcium, chlorine, cobalt(II) fluoride, manganese trifluoride, oxidants, silver fluoride, sodium-potassium alloy... 

Sodium—lead alloys that contain other metals, eg, the alkaline-earth metals, are hard even at high temperatures, and are thus suitable as beating metals. Tempered lead, for example, is a beating alloy that contains 1.3 wt % sodium, 0.12 wt % antimony, 0.08 wt % tin, and the remainder lead. The German BahnmetaH, which was used ia axle beatings on railroad engines and cars, contains 0.6 wt % sodium, 0.04 wt % lithium, 0.6 wt % calcium, and the remainder lead, and has a Brinell hardness of 34 (see Bearing MATERIALS). 

The electrolysis Of fused alkali salts.—Many attempts have been made to prepare sodium directly by the electrolysis of the fused chloride, since that salt is by far the most abundant and the cheapest source of the metal. The high fusion temp. the strongly corrosive action of the molten chloride and the difficulty of separating the anodic and cathodic products, are the main difficulties which have been encountered in the production of sodium by the electrolysis of fused sodium chloride. Attention has been previously directed to C. E. Acker s process for the preparation of sodium, or rather a sodium-lead alloy, by the electrolysis of fused sodium chloride whereby sodium is produced at one electrode, and chlorine at the other but the process does not appear to have been commercially successful. In E. A. Ashcroft s abandoned process the fused chloride is electrolyzed in a double cell with a carbon anode, and a molten lead cathode. The molten lead-sodium alloy was transported to a second chamber, where it was made the anode in a bath of molten sodium hydroxide whereby sodium was deposited at the cathode. A. Matthiessen 12 electrolyzed a mixture of sodium chloride with half its weight of calcium chloride the addition of the chloride of the alkaline earth, said L. Grabau, hinders the formation of a subchloride. J. Stoerck recommended the addition of... 

The distillation of ethers from lithium aluminum hydride occasionally leads to an explosion. The exact cause is not known, but C02 may be involved. The danger can be minimized by predrying the ether with calcium hydride and then using a minimum amount of LiAlH for final distillation. Also, the distillation should be performed behind a blast shield, and the still pot should never be allowed to go dry. Frequently, a safe but powerful desiccant, such as benzophenone ketyl or sodium-potassium alloy, may be used in place of LiAIH4. 

Diethyl sulfate is also reactive with sodium-lead alloy 293> and calcium-lead alloy 200,201) to form R4Pb. With NaPb, the stoichiometry is ... 

Caution. Sodium-potassium alloy reacts vigorously with air and must be handled in a good inert-atmosphere box. Solvents should be dried first over calcium hydride or have a very low water content before one attempts to dry them further over sodium-potassium alloy. 

It follows from this discussion that all solvents and monomers used must be carefully purified. Hydrocarbons should be stirred over sulphuric acid for many days and ethers refluxed over sodium—potassium alloy or sodium fluorenone before fractionation. Traces of unsaturated materials in aliphatic hydrocarbons can be removed by silica gel. After fractionation, a preliminary drying over calcium hydride can be followed by storage over sodium—potassium alloy for ethers, or a treatment with butyllithium or similar non-volatile reactive organometallic reagent for hydrocarbons. Monomers cannot be treated quite so drastically, but fractionation followed by a pre-polymerization in vacuum over butyl-... 

In the presence of TMS-Cl the enediolate dianion and, importantly, the alkoxide ions, are trapped as their neutral silyl ethers (Scheme 5). This leads to much improved yields of the coupled product the acyloin is isolated in the form of its silyl enediol ether (3). Work-up is much easier. It is only necessary to filter the solution, evaporate the solvent, and isolate the product by distillation or chromatography. The TMS-Cl should be purified by distillation from calcium hydride, under a nitrogen or argon atmosphere, before use. A convenient procedure when using an organic solvent is to add the ester and the TMS-Cl together, dropwise, to the alkali metal finely dispersed in the solvent, at a rate sufficient to maintain the reaction. An explosion has been reported where this procedure was not followed. For a reaction conducted in liquid ammonia the TMS-Cl is added at the end of the reaction and after all the ammonia has been allowed to evaporate. Particularly in cases where sodium-potassium alloy has been used, a pyrophoric residue may have formed, so that the filtration must be carried out under an inert atmosphere. 

Cooling Separates fuel from air Beryllium Calcium Lithium Magnesium Potassium Sodium Sodium-potassium alloy Titanium Uranium Zirconium Other metals and commodities not specified. Typically not used for automatic systems but applied manually or from a fire extinguisher. Non-toxic... 

French) or BROMOFORMO (Spanish) (75-25-2) CHBrj Noncombustible liquid. Violent reaction with chemically active metals, acetone, calcium, strong caustics, potassium, potassium hydroxide, sodium hydroxide. Increases the explosive sensitivity of nitromethane. Incompatible with crown polyethers, sodium-potassium alloys. Forms friction- and shock-sensitive compounds with lithium. Aqueous solution is a medium-strong acid. Liquid attacks some plastics, rubber, and coatings. Corrosive to most metals in the presence of moisture. Thermal decon osition products include highly toxic carbonyl bromide and hydrogen bromide fumes. On small fires, use dry chemical powder (such as Purple-K-Powder), foam, or COj extinguishers. 

---