Potassium alloys

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

The most commonly used Hquid metal is sodium—potassium eutectic. Sodium, potassium, bismuth, lithium, and other sodium—potassium alloys also are used. Mercury, lead, and lead—bismuth eutectic have also been used however, these are all highly toxic and appHcation has thus been restricted. 

These reactions are usehil for the preparation of homogeneous difunctional initiators from a-methylstyrene in polar solvents such as tetrahydrofuran. Because of the low ceiling temperature of a-methylstyrene (T = 61° C) (26), dimers or tetramers can be formed depending on the alkaU metal system, temperature, and concentration. Thus the reduction of a-methylstyrene by sodium potassium alloy produces the dimeric dianionic initiators in THF (27), while the reduction with sodium metal forms the tetrameric dianions as the main products (28). The stmctures of the dimer and tetramer correspond to initial tail-to-tail addition to form the most stable dianion as shown in equations 6 and 7 (28). 

The second important component is the cooling agent or reactor coolant which extracts the heat of fission for some usefiil purpose and prevents melting of the reactor materials. The most common coolant is ordinary water at high temperature and high pressure to limit the extent of boiling. Other coolants that have been used are Hquid sodium, sodium—potassium alloy, helium, air, and carbon dioxide (qv). Surface cooling by air is limited to unreflected test reactors or experimental reactors operated at very low power. 

Sodium—potassium alloy is easily prepared by melting the clean metals ia an iaert atmosphere or under an iaert hydrocarbon, or by the reaction of sodium with molten KCl, KOH, or soHd K CO powder. 

Sodium amalgam is employed ia the manufacture of sodium hydroxide sodium—potassium alloy, NaK, is used ia heat-transfer appHcations and sodium—lead alloy is used ia the manufacture of tetraethyllead and tetramethyUead, and methylcyclopentadienylmanganesetricarbonyl, a gasoline additive growing ia importance for improving refining efficiency and octane contribution. 

Preparation of Acyloins. When aUphatic esters are allowed to react with metallic sodium, potassium, or sodium—potassium alloy in inert solvents, acyloins (a-hydroxyketones) are formed (45) ... 

Sodium-potassium alloy. Used as lumps. Lower melting than sodium, so that its surface is readily renewed by shaking. Properties and applications are similar to those for sodium. 

Dry benzene was obtained by doubly distilling high purity benzene from a soln containing the blue ketyl formed by the reaction of sodium-potassium alloy with a small amount of benzophenone. 

Metbyl-l-pentene [763-29-1] M 84.2, b 61.5-62", d 0.680, n 1.395. Water was removed, and peroxide formation prevented by several vacuum distns from sodium, followed by storage with sodium-potassium alloy. 

Caution Disposal of residues must he made with care. When excess metal, especially sodium-potassium alloy, is used, the residues can be pyrophoric ... 

Sodium, potassium and sodium-potassium alloys Liquid sodium, potassium or alloys of these elements have little effect on niobium at temperatures up to 1 000°but oxygen contamination of sodium causes an increase in corrosionSodium does not alloy with niobium . In mass transfer tests, niobium exposed to sodium at 600°C exhibited a corrosion rate of approximately 1 mgcm d . However, in hot trapped sodium at 550°C no change of any kind was observed after 1 070 h . 

Ethyl Phenylmalonate (16, 33) By condensing ethyl phenylacetate with ethyl carbonate using a sodium-potassium alloy. Skinner, J. Am. Chem. Soc. 59, 322... 

It might be amusing to conclude this section by noting the structure that a l,2,3,4-tetrahydro-l,2,3,4-tetraborete assumes. Treatment of ferf-butylboron difluoride with sodium-potassium alloy (Eq. 28) gives a derivative (92) of such a system, whose XRD analysis reveals that the nuclei assume a maximally folded structure—namely a tetrahedron.91... 

Bonilla, C. F., D. L. Sawhuey, and N. M. Makansi, 1962, Vapor Pressure of Alkali Metals III, Rubidium, Cesium, and Sodium-Potassium alloy up to 100 psia, Proc. 1962 High Temperature Liquid MetaI Heat Transfer Tech. Meeting, BNL-756, Brookhaven, NY. (3)... 

Madsen, N., and C. F. Bonilla, 1959, Heat Transfer to Boiling Sodium and Potassium Alloy, AIChE... 

See Dibromomethylborane Sodium-potassium alloy (next below) See related alkylboranes... 

See other self-heating and ignition incidents Sodium-potassium alloy... 

Use of potassium graphite or caesium graphite to generate methylborylene is uneventful, while use of sodium-potassium alloy (1 5 mol) caused an explosion in 2 out of 5 attempts. 

Mixtures of the red or yellow oxides with sodium-potassium alloy explode violently on impact, the yellow (more finely particulate) oxide giving the more sensitive mixture [1], Mixtures with magnesium or potassium may explode on heating [2],... 

Reductive dehalogenation cannot be completely controlled, and mostly complicated mixtures were formed which are difficult to separate. Salt elimination opens the possibility of a reaction aimed at polysilane formation. Some examples are shown in Fig. 2. The key compounds are the alkali metal cyclosilanes, which we have isolated via the mercury compounds by the action of sodium/potassium alloy and used for the first time [13]. 

Nuclear and magneto-hydrodynamic electric power generation systems have been produced on a scale which could lead to industrial production, but to-date technical problems, mainly connected with corrosion of the containing materials, has hampered full-scale development. In the case of nuclear power, the proposed fast reactor, which uses fast neutron fission in a small nuclear fuel element, by comparison with fuel rods in thermal neutron reactors, requires a more rapid heat removal than is possible by water cooling, and a liquid sodium-potassium alloy has been used in the development of a near-industrial generator. The fuel container is a vanadium sheath with a niobium outer cladding, since this has a low fast neutron capture cross-section and a low rate of corrosion by the liquid metal coolant. The liquid metal coolant is transported from the fuel to the turbine generating the electric power in stainless steel... 

Hexafluorothioacetone, 50, 83 Hexamethylbicyclo[1.1.0]butane, from 1,3-dibromohexamethyl-cyclo butane and sodium-potassium alloy, 51, 58 Hexamethylphosphoramide, 50,... 

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