Chlorine zirconium

Zirconium is stable in NH3 up to about 1000°C, in most gases (CO, CO2 and SO2) up to about 300—400°C, and in dry halogens up to about 200°C. At elevated temperatures, zirconium forms volatile halides. Depending on the surface condition, zirconium may or may not be resistant in wet chlorine. Zirconium is susceptible to pitting in wet chlorine unless it has a properly cleaned surface. 

Lead Ammonium nitrate, chlorine trifluoride, hydrogen peroxide, sodium azide and carbide, zirconium, oxidants... 

In France, Compagnie Europnene du Zirconium (CEZUS) now owned jointly by Pechiney, Eramatome, and Cogema, uses a separation (14) based on the extractive distillation of zirconium—hafnium tetrachlorides in a molten potassium chloride—aluminum trichloride solvent at atmospheric pressure at 350°C. Eor feed, the impure zirconium—hafnium tetrachlorides from the zircon chlorination are first purified by sublimation. The purified tetrachlorides are again sublimed to vapor feed the distillation column containing the solvent salt. Hafnium tetrachloride is recovered in an enriched overhead fraction which is accumulated and reprocessed to pure hafnium tetrachloride. 

Chlorination. In some instances, the extraction of a pure metal is more easily achieved from the chloride than from the oxide. Oxide ores and concentrates react at high temperature with chlorine gas to produce volatile chlorides of the metal. This reaction can be used for common nonferrous metals, but it is particularly useful for refractory metals like titanium (see Titanium and titanium alloys) and 2irconium (see Zirconium and zirconium compounds), and for reactive metals like aluminum. 

Heated zirconium is readily chlorinated by ammonium chloride, molten stannous chloride, zinc chloride, and chlorinated hydrocarbons and the common chlorinating agents. It is slowly attacked by molten magnesium chloride in the absence of free magnesium, which is always present in the KroU process. 

Chlorination. Historically, the production of zirconium tetrachloride from zircon sand involved first a reduction to carbide nitride (see above) followed by the very exothermic reaction of the cmshed carbide nitride with chlorine gas in a water-cooled vertical shaft furnace ... 

Zirconium tetrachloride, ZrCl, is prepared by a variety of anhydrous chlorination procedures. The reaction of chlorine or hydrogen chloride with zirconium metal above 300°C, or phosgene or carbon tetrachloride on zirconium oxide above 450°C, or chlorine on an intimate mixture of zirconium oxide and carbon above 700°C are commonly used. 

Zirconium tetrachloride is a tetrahedral monomer in the gas phase, but the soHd is a polymer of ZrCl octahedra arranged in zigzag chains in such a way that each zirconium has two pairs of bridging chlorine anions and two terminal or t-chlorine anions. The octahedra are distorted with unequal Zr—Cl bridge bonds of 0.2498 and 0.2655 nm. The physical properties of zirconium tetrachloride are given in Table 7. 

Zirconium tetrachloride is instantly hydrolyzed in water to zirconium oxide dichloride octahydrate [13520-92-8]. Zirconium tetrachloride exchanges chlorine for 0x0 bonds in the reaction with hydroxylic ligands, forming alkoxides from alcohols (see Alkoxides, METAl). Zirconium tetrachloride combines with many Lewis bases such as dimethyl sulfoxide, phosphoms oxychloride and amines including ammonia, ethers, and ketones. The zirconium organometalLic compounds ate all derived from zirconium tetrachloride. 

Photochlorination of tetrachloroethylene, observed by Faraday, yields hexachloroethane [67-72-1]. Reaction with aluminum bromide at 100°C forms a mixture of bromotrichloroethane and dibromodichloroethane [75-81-0] (6). Reaction with bromine results in an equiUbrium mixture of tetrabromoethylene [79-28-7] and tetrachloroethylene. Tetrachloroethylene reacts with a mixture of hydrogen fluoride and chlorine at 225—400°C in the presence of zirconium fluoride catalyst to yield l,2,2-trichloro-l,l,2-trifluoroethane [76-13-1] (CFG 113) (7). 

Dichlorotoluene (2,4-dichloro-l-methylben2ene) constitutes 80—85% of the dichlorotoluene fraction obtained in the chlorination of PCT with antimony trichloride (76) or zirconium tetrachloride (77) catalysts. It is separated from 3,4-dichlorotoluene (l,2-dichloro-4-methylben2ene), the principal contaminant, by distillation. Chlorination of OCT with sulfuryl chloride gives mainly 2,4-dichlorotoluene and small amounts of the 2,3 isomer (78). 

Chlorination of ores of uranium, titanium, zirconium and aluminum. For titanium, carbon also is needed ... 

The Kroll process for tire reduction of tire halides of refractory metals by magnesium is exemplified by the reduction of zirconium tetrachloride to produce an impure metal which is subsequently refined with the van Arkel process to produce metal of nuclear reactor grade. After the chlorination of the impure oxide in the presence of carbon... 

Refractory metals Zirconium Hafnium Titanium Kroll process, chlorination, and magnesium reduction Chlorine, chlorides, SiCli Wet scrubbers... 

Zirconium phthalocyanine (PcZrCl2) is prepared in a high-boiling solvent like 1-chloro-naphthalene using phthalonitrile and zirconium(IV) chloride.222 If the reaction is carried out without solvent, chlorination of the phthalocyanine ring may occur as a side reaction.223,224... 

Similar to the mixed-halide (Cl, I) 6-13 system, where more chlorine-rich reactions produced a new structure type, materials with an unprecedented zirconium cluster structure are obtained in the Na-Zr-(C1/I)-B system (also with. other cations, see below), when larger Cl/I ratios are used than above. Compounds characterized are Na[(Zr6B)(Cl,I)i4] and Ao.5[(Zr6B)(Cl,I)i4] (with A = Ca, Sr, Ba) [25, 26]. Single crystals of the cubic Na[(Zr6B)Clio.94(i)l3.o6] and... 

An extension of the reduction-chlorination technique described so far, wherein reduction and chlorination occur simultaneously, is a process in which the oxide is first reduced and then chlorinated. This technique is particularly useful for chlorinating minerals which contain silica. The chlorination of silica (Si02) by chlorine, in the presence of carbon, occurs above about 1200 °C. However, the silica present in the silicate minerals readily undergoes chlorination at 800 °C. This reaction is undesirable because large amounts of chlorine are wasted to remove silica as silicon tetrachloride. Silica is, therefore, removed by other methods, as described below, before chlorination. Zircon, a typical silicate mineral, is heated with carbon in an electric furnace to form crude zirconium carbide or carbonitride. During this treatment, the silicon in the mineral escapes as the volatile oxide, silicon monoxide. This vapor, on contact with air, oxidizes to silica, which collects as a fine powder in the furnace off-gas handling system ... 

The mono- and di-alkali metal acetylides, copper acetylides, iron, uranium and zirconium carbides all ignite in chlorine, the former often at ambient temperature. See Caesium acetylide Halogens Dicopper(I) acetylide Halogens Iron carbide Halogens... 

Examinations of the far-infrared spectra of solutions of Zr (allyl) 3CI and Zr (allyl) 2CI2 (9) suggest that the former exists in solution as the dimer (X), whereas the latter has the monomeric structure (XI). A broad intense peak at 244 cm-1 can be assigned to zirconium-bridging chlorine stretching mode. This band is completely absent from the spectrum of the dihalide and is replaced by a very strong band at 342 cm-1 due to the nonbridging chlorine. 

Iodoform Iodomethane Iron disulfide Isothiourea Ketones Lactonitrile Lead Acetone, lithium, mercury(II) oxide, mercury(I) chloride, silver nitrate Silver chlorite, sodium Water, powdered pyrites Acrylaldehyde, hydrogen peroxide, nitric acid Aldehydes, nitric acid, perchloric acid Oxidizing materials Ammonium nitrate, chlorine trifluoride, hydrogen peroxide, sodium azide and carbide, zirconium, oxidants... 

Lead(II) oxide tungsten, zirconium Chlorinated rubber, chlorine, ethylene, fluorine, glycerol, metal acetylides, perchloric acid... 

The marked difference in reaction efficiency that arises when different sources of metallocene are employed in the (ebthi)Zr-catalyzed hydrogenation is illustrated in Table 6.5. The mechanism by which MAO converts the zirconium(IV) salts to the active zirconium hydride species remains unclear [122]. However, it has been proposed that a chlorine atom may form an q2-bridge between aluminum and zirconium when the dichloride salt is used, thereby preventing formation of the active cationic metal center. 

Zheng et al. [1] postulated that the driving force for placing Zr and B on the same carbon might stem from interactions between the zirconium and oxygen or boron and chlorine atoms. However, an X-ray analysis of 22 revealed that there are no intra- or intermo-lecular interactions between any of these atoms [35]. Compound 22 was also unambiguously characterized by 1H-1H double quantum filtered COSY [36] and 13C-1H heteronuc-lear chemical shift correlation NMR spectroscopy [37,38]. Considerable differences in the chemical shifts of the diastereotopic Cp groups were found in both the XH and 13C NMR spectra. The NMR study unequivocally showed that the methine proton was at-... 

In order to remove effectively iodide by RNDS , oxidation of iodide to iodate or periodate is necessary. Iodide is oxidised to iodate with excess chlorine. Through contact of dechlorinated brine with the ion-exchange resin containing zirconium hydroxide, the iodide is therefore removed from the brine. 

Preparation. It is made by the Kroll method that involves the reaction of chlorine and carbon upon baddeleyite (Zr02). The resultant zirconium tetrachloride, ZrCl4,... 

Safety precautions applicable to direct liquid phase fluorination of aromatic compounds are discussed [1]. Attention is drawn to the hazards attached to the use of many newer fluorinating agents [2], In a study of fluorination reactions of hafnium and zirconium oxides by the fluoroxidisers xenon difluoride, chlorine trifluoride and bromine trifluoride, reactivity decreased in the order given [3],... 

Example The high-resolution spectrum in the molecular ion range of a zirconium complex is typified by the isotopic pattern of zirconium and chlorine (Fig. 3.22). Zr represents the most abundant isotope of zirconium which is accompanied by Zr, r, Zr and Zr, all of them having considerable abun-... 

Zirconium s common oxidation state is +4, but when combined with chlorine and other halogens, it can exist in +2 and +3 oxidation states, as follows ... 

The metal is most often recovered from its principal ore, zircon. The ore is mined, crushed and preliminary segregation is by gravity, electrostatic, and magnetic separation. Separated ore mixed with carbon is charged into an arc furnace and heated to about 3,500°C. This forms zirconium carbide and silicon monoxide, and the monoxide is driven off as vapor. Zirconium carbide is then placed in a chlorinator and heated with chlorine gas at high temperatures. The carbide is converted to zirconium tetrachloride, ZrCfl. Also, small amounts of hafnium that is always associated with zirconium converts to its tetrachloride, HfCfl. 

Zirconium metal is produced from its tetrachloride by reduction with magnesium by the Kroll process. The oxide obtained above is converted to zirconium tetrachloride by heating with carbon and chlorine. In practice, the oxide is mixed with lampblack, powdered sugar, and a little water, and pelletized. The dried pellet is then heated with chlorine in a chlorinator to produce ziro-conium tetrachloride ... 

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