Classifications

• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
  • C01F5/00—Compounds of magnesium
  • C01F5/26—Magnesium halides
  • C01F5/30—Chlorides
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B33/00—Silicon; Compounds thereof
  • C01B33/08—Compounds containing halogen
  • C01B33/107—Halogenated silanes
  • C01B33/1071—Tetrachloride, trichlorosilane or silicochloroform, dichlorosilane, monochlorosilane or mixtures thereof
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B35/00—Boron; Compounds thereof
  • C01B35/06—Boron halogen compounds
  • C01B35/061—Halides
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B9/00—General methods of preparing halides
  • C01B9/02—Chlorides
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
  • C01F7/00—Compounds of aluminium
  • C01F7/48—Halides, with or without other cations besides aluminium
  • C01F7/56—Chlorides
  • C01F7/62—Purification
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
  • C01G1/00—Methods of preparing compounds of metals not covered by subclasses C01B, C01C, C01D, or C01F, in general
  • C01G1/06—Halides

Definitions

• the invention herein relates to the production of metal and metalloid chlorides from their oxides. More particularly it relates to a method of purifying the chloride product stream of undersirable impurities from the chlorination reaction.
• metals and metalloids can be produced by reduction of their chlorides, and that the chlorides themselves can be produced by the chlorination of various metal and metalloid compounds, notably the metal oxides or oxide-containing compositions. Typical of the metals which can be so produced are titanium from TiCl 4 reacted from titania, and magnesium from MgCl 2 reacted from magnesia.
• metals and metalloid compounds notably the metal oxides or oxide-containing compositions.
• Typical of the metals which can be so produced are titanium from TiCl 4 reacted from titania, and magnesium from MgCl 2 reacted from magnesia.
• AICI3 reduction bf aluminum chloride
• the aluminum chloride itself may be produced by reductive chlorination of alumina or aluminous oxides with chlorine in the presence of a carbonaceous reductant. The chemistry of this reaction is well known, having been described in numerous publications including U.S. Patent No. 3,760,066.
• U.S. Patent No. 3,786,135 describes the gaseous products of the reaction as including aluminum chloride, carbon oxides and entrained solid and liquid particles including aluminum, carbon, aluminum oxychloride and/or aluminum hydroxychloride as well as condensable volatile constituents.
• gaseous products of the reaction as including aluminum chloride, carbon oxides and entrained solid and liquid particles including aluminum, carbon, aluminum oxychloride and/or aluminum hydroxychloride as well as condensable volatile constituents.
• Various processes have been proposed for elimination or reduction for these unwanted byproducts; for instance, the aforesaid U.S. Patent No. 3,786,135 describes a process involving multi-stage selective cooling to separate the gaseous aluminum chloride product from the unwanted gaseous components.
• a similar process is described in U.S. Patent No. 3,929,975.
• PCBs polychlorinated biphenyls
• the process comprises subjecting the gaseous stream to the application of thermal energy in the presence of hydrogen or a surface active material, or both, for a time and at a temperature sufficient to reduce the organohalogen compounds but not materially adversely affect the metal or metalloid chlorides.
• Preferred surface active materials include the solid feed material itself which is to be chlorinated, similar oxides or carbonaceous materials, which may if desired be activated.
• the surface active material must also be such that it is either inert toward the hydrogen, metal chloride and chlorine, or, if reactive, such that any product formed will not contaminate the chloride product.
• the organohalogen content in the product chloride stream may be reduced by from 50 percent to 99.8 percent or better.
• the invention herein involves subjecting the gaseous product stream from the reaction in which a metal or metalloid chloride (exemplified-by aluminum chloride) is produced by reductively chlorinating the corresponding oxide (or a mixture containing the oxide) with a carbonaceous reductant (e.g., carbon) and chlorine, to the application of thermal energy in the presence of hydrogen or a surface active material, or both, for a time and at a temperature sufficient to reduce or substantially eliminate the organohalogen content of the stream without materially affecting the desired gaseous chloride product.
• a metal or metalloid chloride exemplified-by aluminum chloride
• a carbonaceous reductant e.g., carbon
• chlorine e.g., chlorine
• thermal energy which may be used in this process to initiate and promote the reduction reactions, including microwave and radio frequency (RF) energy.
• RF radio frequency
• These latter forms require relatively high temperature environments to produce economically feasible reaction rates. They also use specialized equipment which is not normally found in chemical plants and which adversely effects the economics of the process.
• the thermal energy may also be supplied to the reaction by infrared radiant heaters, gas-fired reactors or other known types of thermal energy generators through which the gaseous product stream may be passed or in which it may be contained.
• the application of thermal energy to the gaseous product stream in this process must be done in the presence of hydrogen, a surface active material, or both.
• hydrogen When hydrogen is to be used, it may be present as hydrogen gas, producer gas or a reducing gas such as methane.
• a surface active material When a surface active material is to be present, it must be one which promotes the degradation of the organohalogen compounds. However, it must not attack the hydrogen, chlorine or metal or metalloid chloride product present. It may be inert to these components, or, if reactive with any component, it must not produce any reaction product which attacks, degrades or contaminates the chloride. In some cases the surface active material may be one of the reactants itself, such as alumina in the aluminum chloride process. Other suitable materials include carbonaceous materials such as coke or activated carbon. Among other materials which may suitably be used are compositions which contain oxides in their mixture of components, such as the partially calcined aluminum chloride hexahydrate (PCACH) produced according to the process of co-pending U.S.
• PCACH partially calcined aluminum chloride hexahydrate
• Cokes may include fully calcined, partially calcined or pretreated petroleum coke.
• the materials may be further surface activated, as with activated carbon or activated alumina, by conventional means. Surface areas of the surface active materials may vary widely; satisfactory results have been obtained with coke having a surface area of 1.8 m 2 /q, alumina at approximately 80 m /g and highly disordered activated carbon at 1400 m /g. As will be seen from the Examples below, better results were obtained with the higher surface area materials.
• the process herein may be operated in a wide variety of combinations with the aluminum chloride production process.
• alumina, coke and chlorine may be reacted in a chlorinator with the product stream containing the gaseous aluminum chloride and organohalogen compounds then being passed to a decomposer in which the present process is operated using hydrogen and with thermal energy creating a temperature in the range of 200°-650°C (390 ⁇ -1200 ⁇ .F) in the presence of an activated alumina, carbon or coke.
• the surface active material is spent, it is recycled to the chlorinator to serve as a reactant therein.
• a purified gaseous aluminum chloride stream is recovered from the decomposer.
• Fluid bed reactor 1 is either continuously or batch fed with starting materials 3 such as the aforesaid PCACH (an oxide-containing composition) mixed with a coke activated by partial calcination (typically in a weight ratio of 80:20 respectively) .
• Chlorine gas 2 (which may be mixed with nitrogen gas) is fed to the bottom of the reactor 1 to fludize the solid reactants and to chlorinate the PCACH to produce anhydrous aluminum chloride (AICI3) .
• AICI3 produced flows upward to mixing chamber 5 where it is mixed with hydrogen or nitrogen gas 4 or both.
• the product gas stream also contains all the undesirable chlorinated by-product gases such as PCBs.
• the mixed gas streams flow into reaction bed 6 containing the surface active material, such as activated alumina or coke or one or more of the reactant materials, such as PCACH.
• the bed is heated to the desired temperature by heating coils 7.
• the chlorinated hydrocarbons are decomposed to chlorine gas, hydrocarbons, water vapor and/ or carbon oxides.
• the AICI3 is then recovered in desublimer 8 while the other gases pass through to scrubber 9 where they are separated and the chlorine recovered. This type of apparatus was utilized in the Examples below.
• Example 1 The following Examples will illustrate several embodiments of the present invention.
• Example 1 The following Examples will illustrate several embodiments of the present invention.
• the alumina/coke mixture was the PCACH/coke reaction mixture to a test reactor (as reactor 1 in the Figure) . It will be seen by comparison of the data of Tables 1 and 2 with these data that, except at low temperature, the combination of the surface active material and the hydrogen has a synergistic effect, reducing the organohalogen compound content below that obtained with the surface active material or hydrogen alone. It is preferable from an economic point of view to use the chlorination reactor feed (i.e., the alumina/coke mixture) as the surface active - 13 -
• Example 4 The experiments of Example 4 were repeated but with a surface active material present along with the hydrogen.
• the particular surface active material used was the alumina (PCACH)/coke feed to the system.
• the results of these experiments are illustrated in Table 5 below. - 15 -
• Equations 1 and 2 are fitted from experimental data and therefore represent statistical approximations of reaction kinetics. Those using these equations (or analogous equations derived from other data samples) can expect that individual runs will yield organohalogen contents which will vary from the values predicted by those equations by increments which themselves are within statistically defined ranges. All such results are intended to be included within the scope of this invention.
• this invention is also applicable to removing organohalogens from the product streams of the chlorination to other metal chloride products.
• the production of MgCl 2 produces organohalogens according to the reaction:
• the C x Cl y content can be controlled as described by application of thermal energy to the product stream in the presence of hydrogen and/or a surface active material (e.g., megnesia, titania or zinconia) .
• a surface active material e.g., megnesia, titania or zinconia
• the invention herein is applicable for reducing organohalogen compound content in a gaseous stream con ⁇ taining a metal or metalloid chloride.

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• General Health & Medical Sciences (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

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• 1986
  • 1986-06-13 WO PCT/US1986/001294 patent/WO1987000157A1/en not_active Application Discontinuation
  • 1986-06-13 EP EP19860904519 patent/EP0227797A4/de not_active Withdrawn
  • 1986-06-13 AU AU61227/86A patent/AU585051B2/en not_active Ceased
  • 1986-06-13 BR BR8606749A patent/BR8606749A/pt unknown
  • 1986-06-13 JP JP50357486A patent/JPS63500096A/ja active Pending

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