Molten sodium

When chlorine is passed over molten sodium or potassium hydroxide, oxygen is evolved, the high temperature causing the chlorate V) ion to decompose ... 

The sodium fusion and extraction, if performed strictly in accordance with the above directions, should be safe operations. In crowded laboratories, however, additional safety may be obtained by employing the follow ing modification. Suspend the hard-glass test-tube by the rim through a hole in a piece of stout copper sheet (Fig. 69). Place 1 -2 pellets of sodium in the tube, and heat gently until the sodium melts. Then drop the organic compound, in small quantities at a time, down — =. the tube, allowing the reaction to subside after each addition before the next is made. (If the compound is liquid, allow two or three small drops to fall at intervals from a fine dropping-tube directly on to the molten sodium.) Then heat the complete mixture as before until no further reaction occurs. 

Sodamide. This substance is prepared by the reaction between gaseous ammonia and molten sodium ... 

Ionic bonding was proposed by the German physicist Walther Kossel in 1916 in or der to explain the ability of substances such as molten sodium chloride to conduct an electric current He was the son of Albrecht Kossel winner of the 1910 Nobel Prize in physiology or medi cine for early studies in nu cleic acids... 

Reaction of benzenesulfomc acid with sodium hy droxide This is the oldest method for the prepara tion of phenol Benzene is sulfonated and the ben zenesulfonic acid heated with molten sodium hy droxide Acidification of the reaction mixture gives phenol... 

Electrolytic plant producing metallic sodium and chlorine from molten sodium chlorine. 

Chemica.1 Properties. The FEP resin is inert to most chemicals and solvents, even at elevated temperatures and pressures. However, it reacts with fluorine, molten alkah metal, and molten sodium hydroxide. Acids or bases are not absorbed at 200°C and exposures of one year. The absorption of organic solvents is less than 1% at elevated temperatures and long exposure times. Absorption of chemicals or solvents has no effect on the chemical integrity of the FEP molecule and is a reversible physical process. 

Sodium hydride is manufactured by the reaction of hydrogen and molten sodium metal dispersed by vigorous agitation ia mineral oil (4). 

Naphthalenediol. This diol is made by the fusion of sodium 2,7-naphthalenedisulfonate with molten sodium hydroxide at 280—300°C in ca 80% yield. A formaldehyde resin prepared from this diol has excellent erosion resistance, strength, and chemical inertness it is used as an ablative material in rocket-exhaust environments (76). 

Full advantage of the neutron production by plutonium requires a fast reactor, in which neutrons remain at high energy. Cooling is provided by a hquid metal such as molten sodium or NaK, an alloy of sodium and potassium. The need for pressurization is avoided, but special care is required to prevent leaks that might result in a fire. A commonly used terminology is Hquid-metal fast-breeder reactor (LMFBR). 

During operation, KCl is melted and introduced through a trap to the column. Molten sodium is fed to the bottom of the column. The lower portion of the column serves as a reactor, the upper portion as a fractionator. Potassium vapor is fractionated and condensed in an air-cooled condenser with the reflux pumped back to the top of the column. Waste sodium chloride is continuously removed from the bottom of the column through a trap. 

Manufacture is either by reaction of molten sodium with methyl alcohol or by the reaction of methyl alcohol with sodium amalgam obtained from the electrolysis of brine in a Castner mercury cell (78). Both these methods produce a solution of sodium methylate in methanol and the product is offered in two forms a 30% solution in methanol, and a soHd, which is a dry, free-flowing white powder obtained by evaporating the methanol. The direct production of dry sodium methylate has been carried out by the introduction of methanol vapors to molten sodium in a heavy duty agitating reactor. The sohd is supphed in polyethylene bags contained in airtight dmms filled in a nitrogen atmosphere. 

Commercial grades of sodium aluminate are obtained by digestion of aluminum tnhydroxide in aqueous caustic at atmospheric pressure and near the boiling temperature (7). Digestion of the aluminum hydroxy oxide in aqueous sodium hycboxide [1310-73-2] requbes pressures of up to 1.38 MPa (13.6 atm) and temperatures of about 200°C. Dry sodium aluminate is obtained by evaporation of water. Several processes for the production of sodium aluminate are known that do not reqube the addition of water. In one process, bauxite reacts with molten sodium hycboxide at approximately 400°C (8) in... 

This reaction is accompanied by a blackening of the vitreous siUca and a flaking of the surface. As evidence for the diffusion step, the sodium absorption by the much denser quartz is 12 mg/(1000 hcm ) at 350°C, whereas vitreous siUca absorbs 23 mg/(1000 hcm ) at 286°C (94). Molten sodium is much less reactive. 

Fig. 3. The viscosity and liquidus curves for molten sodium silicates, where the numbers on the dashed lines ate viscosity ia Pa-s (1).

Sodium and magnesium do not react with tetrachlorosilane at room temperature, but do so at elevated temperatures and ia the presence of polar aprotic solvents at moderately elevated temperatures. The Wurtz-Fittig coupling of organosilanes to form disilanes (168) and polysdanes (169) is usually accomphshed usiag molten sodium ia toluene or xylene. 

Nitrogen and sodium do not react at any temperature under ordinary circumstances, but are reported to form the nitride or azide under the influence of an electric discharge (14,35). Sodium siHcide, NaSi, has been synthesized from the elements (36,37). When heated together, sodium and phosphoms form sodium phosphide, but in the presence of air with ignition sodium phosphate is formed. Sulfur, selenium, and tellurium form the sulfide, selenide, and teUuride, respectively. In vapor phase, sodium forms haHdes with all halogens (14). At room temperature, chlorine and bromine react rapidly with thin films of sodium (38), whereas fluorine and sodium ignite. Molten sodium ignites in chlorine and bums to sodium chloride (see Sodium COMPOUNDS, SODIUM HALIDES). 

Phosphoms trichloride and pentachloride form sodium chloride and sodium phosphide, respectively, in the presence of sodium. Phosphoms oxychloride, POCl, when heated with sodium, explodes. Carbon disulfide reacts violendy, forming sodium sulfide. Sodium amide (sodamide), NaNH2, is formed by the reaction of ammonia gas with Hquid sodium. SoHd sodium reacts only superficially with Hquid sulfur dioxide but molten sodium and gaseous... 

Sodium nitrite has been synthesized by a number of chemical reactions involving the reduction of sodium nitrate [7631-99-4] NaNO. These include exposure to heat, light, and ionizing radiation (2), addition of lead metal to fused sodium nitrate at 400—450°C (2), reaction of the nitrate in the presence of sodium ferrate and nitric oxide at - 400° C (2), contacting molten sodium nitrate with hydrogen (7), and electrolytic reduction of sodium nitrate in a cell having a cation-exchange membrane, rhodium-plated titanium anode, and lead cathode (8). 

Molten sodium is injected into the retort at a prescribed rate and the temperature of the system is controlled by adjusting the furnace power or with external cooling. The variables that control the quaUty and physical properties of the powder are the reduction temperature and its uniformity, diluent type and concentration, sodium feed rate, and stirring efficiency. Optimizing a variable for one powder attribute can adversely affect another property. For example, a high reduction temperature tends to favor improved chemical quaUty but lowers the surface area of the powder. 

The reactivity of titanium dioxide toward acid is dependent on the temperature to which it has been heated. Freshly precipitated titanium dioxide is soluble iu concentrated hydrochloric acid. However, titanium dioxide that has been heated to 900°C is almost iusoluble iu acids except hot concentrated sulfuric, iu which the solubiUty may be further iucreased by the addition of ammonium sulfate to raise the boiling poiut of the acid, and hydrofluoric acid. Similarly, titanium dioxide that has been calciued at 900°C is almost iusoluble iu aqueous alkahes but dissolves iu molten sodium or potassium hydroxide, carbouates, or borates. 

Zirconium is not attacked by caustics up to boiling temperatures. It is resistant to molten sodium hydroxide to 1000°C, but is less resistant to potassium hydroxide. 

Porous carbon and graphite are used ia filtration of hydrogen fluoride streams, caustic solutions, and molten sodium cyanide ia diffusion of chlorine iato molten aluminum to produce aluminum chloride and ia aeration of waste sulfite Hquors from pulp and paper manufacture and sewage streams. 

In the sodium—sulfur storage battery above 300°C, the overall chemical reaction occurs between molten sodium metal and sulfur to form sodium polysulfide. The cell voltage is related to the activity of the sodium ( Aia) sulfide relative to its activity in the metal. 

Chromium (II) also forms sulfides and oxides. Chromium (II) oxide [12018-00-7], CrO, has two forms a black pyrophoric powder produced from the action of nitric acid on chromium amalgam, and a hexagonal brown-red crystal made from reduction of Cr202 by hydrogen ia molten sodium fluoride (32). Chromium (II) sulfide [12018-06-3], CrS, can be prepared upon heating equimolar quantities of pure Cr metal and pure S ia a small, evacuated, sealed quartz tube at 1000°C for at least 24 hours. The reaction is not quantitative (33). The sulfide has a coordination number of six and displays a distorted octahedral geometry (34). 

The Beilby process started in 1891 and by 1899 accounted for half of the total European production of cyanide. In this process, a fused mixture of sodium and potassium carbonates reacts with ammonia ia the presence of carbon. In 1900, the Castner process, in which molten sodium, ammonia, and charcoal react to give a high (98%) grade sodium cyanide, superseded the Beilby process. Sodium cyanide became an article of commerce and soon replaced potassium cyanide in all except special uses. 

Molten sodium cyanide reacts with strong oxidizing agents such as nitrates and chlorates with explosive violence. In aqueous solution, sodium cyanide is oxidized to sodium cyanate [917-61 -3] by oxidizing agents such as potassium permanganate or hypochlorous acid. The reaction with chlorine in alkaline solution is the basis for the treatment of industrial cyanide waste Hquors (45) ... 

These facts would suggest that die electrolysis of molten alkali metal salts could lead to the inuoduction of mobile elecU ons which can diffuse rapidly through a melt, and any chemical reduction process resulting from a high chemical potential of the alkali metal could occur in the body of the melt, rather than being conhned to the cathode volume. This probably explains the failure of attempts to produce tire refractoty elements, such as titanium, by elecU olysis of a molten sodium chloride-titanium chloride melt, in which a metal dust is formed in the bulk of the elecU olyte. 

An important indusuial interest is in the conosion of metals and ceramics by molten sodium sulphate/vanadate solutions. This is because turbines, which are usually nickel-based alloys, operating in a marine anuosphere, containing... 

The spectacular success (in 1807) of Humphry Davy, then aged 29 y, in isolating metallic potassium by electrolysis of molten caustic potash (KOH) is too well known to need repeating in detail." Globules of molten sodium were similarly prepared by him a few days later from molten caustic soda. Earlier experiments with aqueous solutions had been unsuccessful because of the great reactivity of these new elements. The names chosen by Davy reflect the sources of the elements. 

Conventional batteries consist of a liquid electrolyte separating two solid electrodes. In the Na/S battery this is inverted a solid electrolyte separates two liquid electrodes a ceramic tube made from the solid electrolyte sodium /5-alumina (p. 249) separates an inner pool of molten. sodium (mp 98°) from an outer bath of molten sulfur (mp 119°) and allows Na" " ions to pass through. The whole system is sealed and is encased in a stainless steel canister which also serves as the sulfur-electrode current collector. Within the battery, the current is passed by Na+ ions which pass through the solid electrolyte and react with the sulfur. The cell reaction can be written formally as... 

Sodium-Sulfur Batteries. The sodium-sulfur battery consists of molten sodium at the anode, molten sulfur at the cathode, and a solid electrolyte of a material that allows for the passage of sodium only. For the solid electrolyte to be sufficiently conductive and to keep the sodium and sulfur in a liquid state, sodium-sulfur cells must operate at 300°C to 350°C (570°F to 660°F). There has been great interest in this technology because sodium and sulfur are widely available and inexpensive, and each cell can deliver up to 2.3 volts. 

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