Magnesium with titanium tetrachloride

Alternatively, the TiCl may be reduced using hydrogen, sodium, or magnesium. It follows that TiCl2 is the first stage in the KroU process for the production of titanium metal from titanium tetrachloride. A process for recovery of scrap titanium involving the reaction of scrap metal with titanium tetrachloride at >800° C to form titanium dichloride, collected in a molten salt system, and followed by reaction of the dichloride with magnesium to produce pure titanium metal, has been patented (122,123). 

Polyethylene (Ziegler-Natta catalyst). Most commercial catalysts start with titanium tetrachloride, di-ethylaluminum chloride, and magnesium chloride as a... 

By use of weaker reductants, the C-C coupling can be stopped at the stage of the pinacols [48]. The best metals for achieving chemical pinacolization from ketones are magnesium in the form of its amalgam and mixtures of Zn-Hg with titanium tetrachloride (Scheme 11). In the latter reaction the Ti(II) species presumably initiates electron transfer [49]. 

As the first step for the catalyst preparation, the ball-milled magnesium chloride was allowed to stand with titanium tetrachloride at 80 C for two hours. The MgCl (TiCl ), i.e., TiCl adsorbed on MgCl2 was then treated with Et and ethyl benzoate (EB) at 60 C. The catalyst ( )) thus obtained gave the following analytical results ... 

Slurry processes may use a combination of organo-aluminum and organo-magnesium compounds with titanium tetrachloride. Phillips-type catalysts (supported chromium compounds) are also used. Pressures and temperatures are moderate. 

The magnesium dichloride was reacted with 2-ethyl-1-hexanol (1 2 molar ratio) in decane at 120°C for two hours. A stoichiometric amount of dibutylphthalate (DBPh/MgCl = 0.15) was added in the reaction mixture and stirred for one hour at 120°C. The obtained solution was added into decane solution of diphenyl-dichlorosilane (Si/Mg molar ratio = 30) in controlled manner at room temperature. The reaction mixture was heated to 120°C and allowed to react for two hours. The solid product was separated by filtration and washed with hexane. It was treated with titanium tetrachloride (Ti/Mg molar ratio = 40) at 120°C for two hours. The liquid was decanted from reaction mixture at 120°C. The solid product obtained was washed with decane followed by hexane. Catalyst (Mg-Ti) was dried in vacuum for two hours. 

Solid catalyst [Mg-Ti] was analyzed for its composition and specific surface area (Table 2). A 3.0 wt. % of titanium is incorporated on active support. BET surface area of crystalline magnesium dichloride is found to be 10 mVg. The treatment of magnesium dichloride with 2-ethyl-1-hexanol and DBPh followed by diphenyldichlorosilane gives a product [Mg-Ti I] with improved surface area characteristics (50 mVg). The reaction of [Mg-Ti I] with titanium tetrachloride increases the surface area to 115 m /g. These results show that the present process of catalyst synthesis gives approximately tenfold improvement in the surface area of the Mg-Ti catalyst as compared to the starting anhydrous magnesium dichloride. 

Important objectives of the later prodnction methods were to control the size and shape of the catalyst particles during precipitation of the magnesium chloride and to improve stabihty. Catalysts with better-controlled size and shape were based on the reaction of a precipitated magnesium chloride with titanium tetrachloride in a high-boiling-point hydrocarbon diluent at 80°C, with di-isobutyl phthalate added as an internal electron donor. " After separation, the sohd formed was reacted with more titaninm tetrachloride at 120°C, before being washed and dried. The catalyst contained between 2-3% titanium and the phthalates used were hmited to C4-C8 esters to avoid potential problems with colloid formation. The catalysts prodnced with phthalates as the internal donor had mnch higher snrface area and pore volume than when ethyl berrzoate was nsed. This method provided more active arrd stereospecifrc catalysts when used with the same triethyl aluminum co-calalyst and an external electron donor such as phenyl triethoxy silane. 

The metal was a laboratory curiosity until Kroll, in 1946, showed that titanium could be produced commercially by reducing titanium tetrachloride with magnesium. This method is largely used for producing the metal today. The metal can be purified by decomposing the iodide. 

The ease of oxidation of magnesium is important in the commercial manufacture of titanium metal. Titanium, when quite pure, shows great promise as a structural metal, but the economics of production have thus far inhibited its use. One of the processes currently used, the Kroll process, involves the reduction of liquid titanium tetrachloride with molten metallic magnesium ... 

In the production of titanium, the chlorination of rutile generates approximately 0.12 tons of waste for every ton of titanium tetrachloride produced. If ilmenite is directly chlorinated, the amount of waste is 1.5 tons for every ton of titanium tetrachloride. Large amounts of ferric chloride are produced along with volatile chlorides and oxychlorides (e.g., aluminum trichloride, silicon tetrachloride, carbon oxychloride, tin tetrachloride, vanadium tetrachloride, vanadium oxychloride) these can be removed by selective distillation. In flu-idized-bed chlorination, the build-up of liquid calcium chloride and magnesium chloride in the fluid bed interferes with the process of fluidization and hence these must be removed. 

Kroll (1) A process for making a metal by reducing its halide with another metal. Thus titanium is prepared by reducing titanium tetrachloride with magnesium ... 

Sodium reduces most metal chlorides to metals. Thus, when heated with titanium or zirconium tetrachloride, sodium converts the hahdes to free metals. Chlorides of calcium, magnesium, and potassium are only partially reduced. 

The production of titanium always encounters difficulties because of a tendency to react with oxygen, nitrogen and moisture at elevated temperatures. Most high purity elemental titanium can he produced by the Kroll process from titanium tetrachloride. The tetrachloride is reduced with magnesium in a mild steel vessel at about 800° C under an inert atmosphere of helium or argon. The net reaction is as follows ... 

Titanium metal also can be produced by electrolytic methods. In electrolysis, fused mixtures of titanium tetrachloride or lower chlorides with alkaline earth metal chlorides are electrolyzed to produce metal. Also, pure titanium can be prepared from electrolysis of titanium dioxide in a fused bath of calcium-, magnesium- or alkali metal fluorides. Other alkali or alkaline metal salts can be substituted for halides in these fused baths. Other titanium com-pouds that have been employed successfully in electrolytic titanium production include sodium fluotitanate and potassium fluotitanate. 

Titanium trichloride may be prepared by reducing titanium tetrachloride with hydrogen at 600°C. The tetrachloride may alternatively be reduced with aluminum, zinc, magnesium, tin, or by electrolysis. 

Chlorine is useful for the manufacture of many chemical products even though these products themselves contain no chlorine.To create titanium metal, for example, the mineral titanium dioxide is reacted with chlorine to form titanium tetrachloride,TiCl4 (sometimes humorously called "tickle ), which is then reduced by magnesium metal. Mg, as shown in the following equations ... 

KROLL PROCESS. A widely used process for obtaining tilanium melal. Titanium tetrachloride is reduced with magnesium metal at red heal and atmospheric pressure, in the presence of an inert gas blanket of helium or argon. Magnesium chloride and titanium metal are produced. The reaction... 

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