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Home , Potassium hydrosulfide, Potassium pyrosulfate

Dec. 5, 1967 W. L. WILSON 3,356,456 PROCESS FOR PREPARING TITANIUM DIOXIDE Filed Juli y 22, 1965

FIG.3

FIG.

INVENTOR WILLIAM L. WILSON

BY

ATTORNEYS

3,356,456 3. 4 ther defined as also including any oxide of the selected IB, IIA, IIB, and silicon, can be introduced to the vapor members providing such oxide has a mean particle size phase reaction together or separately. diameter in the range specified for the oxides of alumi Furthermore, such sources can be introduced directly num and zirconium hereinbefore. or indirectly to the vapor phase reaction of the titanium In addition to additives of aluminum, zirconium, and tetrahalide and oxygen. the selected metals of Groups IA, IB, IIA, and IIB, noted Thus in the practice of this invention, one or more hereinbefore, there may be further added a source of sources of one or more of the aforementioned additives silicon. may be added in conjunction with an inert gas, or one or Silicon source is defined as any organic or inorganic more of the reactants, or both, compound of silicon including elemental metallic sili O When the process is heated by the combustion of a con which will react with oxygen at the vapor phase re fuel, one or more sources may be added to the fuel or action temperature to form the corresponding metal oxide the products of combustion thereof, e.g., a combustible although it is not intended to indicate that the source ma carbon-containing or sulfur-containing fuel or the com terial actually forms such oxide; that is, the source should bustion products thereof when a process is operated in be capable in this instance of forming the corresponding accordance with U.S. Letters Patents 3,069,282 and 3,105, silicon oxide, e.g., SiO2, whether or not such oxide ac 742. tually is formed during the vapor phase oxidation reac The source of each selected additive may also be added tion. In addition, source is further defined as including directly to the reaction zone 30 independently of the the oxides of silicon, such as silica, providing such oxide reactants, inert gases, or combustible fuels; e.g., one or has a mean particle size below 1.0 micron in diameter as 20 more sources may be added directly to the reaction zone specified for the oxides of aluminum and zirconium here as an atomized spray in a solid, liquid, or gaseous state. inbefore. Furthermore, one or more metallic additives may be To more specifically describe the process of this inven added to the zone 30 by employing an inner furnace wall tion, reference is made to the drawing, and FIGURES 1 5 constructed of a ceramic or firebrick material which to 3, inclusive, which depict apparatus for practicing the 25 contains one or more sources of one or more additives, process invention. e.g., one or more compounds of aluminum, zirconium, FIGURE 1 describes a diagrammatic cross-section view Zinc, alkali metal, or alkaline earth metals. Such source of a concentric orifice-annulus burner fitted in a furnace. material is gradually eroded into the reaction zone due FIGURE 2 further illustrates the construction of the to the high temperature and corrosive nature of the en burner of FIGURE 1, representing a view along line I-I 30 vironment in Zone 30, as noted, for example, in British of FIGURE 1. patent specification 672,753. FIGURE 3 illustrates a diagrammatic cross-section One or more additives, particularly , may view of a burner which may be fitted in the furnace of also be introduced into the reaction zone by employing FIGURE 1 to produce pigmentary titanium dioxide ac a ceramic dedusting edge, as disclosed in copending U.S. cording to the process of this invention. application Serial No. 379,825, filed July 2, 1964, which Referring to FIGURES 1 and 2, reaction zone cham contains a source of the particular additive, e.g., lava ber of furnace A' comprises a concentric steel shell 1. stone containing about 0.5 to 1.5 percent by weight po and an internal lining of firebrick 5 (or other heat re tassium. sistant insulation). At the lower part of furnace A' is a Likewise, the additive may be introduced to the zone conical bottom terminating at outlet 7. At the upper part 40 30 by using a baffle as disclosed in copending U.S. ap of furnace A' is a burner A. plication Serial No. 376,980, filed June 22, 1964, which Burner A is composed of three concentric tubes, 2, 3, is constructed out of the selected additive or a source and 4. Tube 3 is arranged so as to circumscribe tube 4 of the additive. (forming annulus 6) and tube 2 is arranged so as to cir Such sources may also be added directly to the zone cumscribe tubes 3 and 4 (forming annulus 9). Each of 45 30 or to one or more inert or reactant gas streams by the tubes 2 and 3 are evenly spaced from the wall of the emitting the source from one or more plastria arc elec. tube it circumscribes. This is more clearly shown in FIG trodes as disclosed, for example, in copending U.S. patent URE 2, which shows the tube arrangement taken along application Serial No. 354,597, filed March 25, 1964. line II of FIGURE 1. The aluminum and/or zirconium source is added to In the operation of the reactor of FIGURES 1 and 2, 50 the vapor phase oxidation reaction in an amount stif an oxygenating gas typically preheated 900° C. to 1750 ficient to insure the presence of 0.5 to 10.0 mole percent C. is fed to the upper opening in tube. 4, while an inert of aluminum and/or zirconium, basis the moles of titani gas at room temperature up to the temperature of the oxy um oxide formed; equivalent to about 0.17 to 3.38 per genating gas is fed to the opening at the top if tube 3. cent by weight metallic aluminum and about 0.57 to The inert gas may comprise chlorine, nitrogen, bromine, 55 11.40 percent by weight zirconium, based on the weight iodine, argon, helium, krypton, xenon, carbon dioxide, or of the titanium oxide pigment formed. mixtures thereof. Concurrently therewith, titanium tetra Best results are obtained when the source of aluminum halide is fed to the opening at the upper part of tube 2. and/or zirconium is added in a small, effective afiount The titanium tetrahalide has a temperature of 140 C. to equivalent to less than 3.0 percent by weight alumintim about 1200° C. 60 and less than 4.5 percent by weight zirconium, based on Referring to FIGURE 3, burner B, which may be fitted the titanium oxide pigment formed. in furnace A' of FIGURE 1 in replacement of burner A, The Selected metallic source (or sources) of zinc and is composed of three concentric tubes annularly arranged. the other metallic members of Groups, IA, IB, ILLA, and Central oxygenating gas tube 12 is circumscribed by tube IIB may be added to the vapor phase oxidation reaction 11, which in turn is circumscribed by tube 10 such that in amounts ranging from 0.01 to 10,000 parts by weight there is formed annuli 17 and 16. Tube 11 is provided of each selected metal per million parts by weight of with an annular lip 13 at its lower end and tube 10 is titanium oxide obtained from the oxidation reaction. provided with annular lip 14, such that the titanium tetra Generally, there is added less than 6,000 parts by weight halide and inert gas streams are emitted from the an of the metal ion with best results being obtained with nuli 17 and 16 in a direction substantially perpendicular 70 5 to 5,000 parts by weight of the metal ion per million to the direction of flow of the oxygenating gas from tube parts by weight of titanium oxide formed by the oxida 12. In operation, burner B is fed in the same manner as tion reaction. With certain selected highly active metal burner A of FIGURE 1. Such as potassium it may be more desirable to add The source or sources of the various additives, e.g., Substantially less than 1,000 parts by weight per million aluminum, zirconium, metallic members of Groups IA, 75 parts by weight titanium oxide. 3,356,456 5 6 If silicon source is also added to the reaction, it is added in an amount sufficient to insure the presence of (zinc chlorate), ZnCl2 (zinc chloride), ZnCrO (zinc 0.001 to 2.7, preferably 0.01 to 2, mole percent silicon, chromate), ZnCr2O3.H2O (zinc dichromate), basis the moles of titanium oxide pigment product formed Zn3 (C6H5O) 2 2HO by the reaction; that is, 0.00035 to about 0.945, prefer (zinc citrate), Zn(CN), (zinc cyanide, ably 0.0035 to 0.70, percent by weight silicon ion based 5 Zn (HO ) 6GaF5 o 5??? on the weight of the titanium oxide pigment formed. (zinc fluogallate), ZnF, (zinc fluoride), ZnSiF6HO Although favorable results are obtained in the range of (zinc fluosilicate), Zn(HSO2-CHO), 0.2 to 1.2 mole percent silicon ion per mole of titanium Zn((OH)HSO2CH2O (zinc formaldehydesulfoxylate), oxide formed, equivalent to 0.07 to 0.42 percent by weight Zn(CHO2)2 (zinc formate), ZnCHOHO, titanium oxide, best results being obtained particularly 0 in the presence of aluminum and zinc or potassium ion (zinc tartrate), Zn(SCN)2 (zinc thiocyanate), when the silicon ion is added in a small, effective amount of less than 0.3 percent by weight, based on the weight ???? Zn(CgHgO,)2?2H2O of the titanium oxide. 5 (zinc valerate), [Zn(NH3)2]Cl2 (zinc diaminezinc chilo The total metallic ions added to the reaction (e.g., ride), Zn(CH2CH2CH2CH3)2 (zinc di-n-butylzinc), Zr, Si, Zn, K, etc.) should not exceed 10 percent by weight of the titanium oxide formed with more effective results being obtained below 6.0 percent by weight. Best results are obtained below 4.0 percent. Specific sources of aluminum include, not by way of 20 limitation, metallic aluminum, organic and inorganic com (zinc diphenylzinc), Zn(CH2CH2CH3)2 (zinc di-n-pro pounds containing aluminum including oxides, hydrox pylizinc), Zn (C6H4CH3)2 (zinc di-o-toylzinc), ides, nitrates, nitrides, sulfides, sulfates, and halides such as Al(CH3O)3 (aluminum acetate), Al(OH)(CH3O2)2 -25 (aluminum acetate, basic), AlC6H5O1 (aluminum ci (zinc formate), ZnGa2O4 (zinc, gallate), ZnCHOP trate), AlCl3, AlCl, AlBr3, AlBr, AlI3, AlI, AlF3, AlF, (zinc glycerophosphate), Zn(OH)2 (zinc hydroxide) Al(ClO3)36H2O (aluminum chlorate), Al(OH)3, Al2O3, Al(NO3)3-9H2O, Al2N2, Al(SO4)3, Al2S3, H3AlF6, AlN the aluminum ammonium halides such as AlClaNH3, 30 (zinc iodate), Zn(IO2)2•2H2O, ZnI2 (zinc iodride), NH4Al(SO4)2, and aluminum containing esters, for ex Zn (CHO) 2 3?,? ample, aluminum compounds containing one or more or (zinc di-lactate), Zn(C3H3O2)2•2H2O (zinc di-lactate), ganic ester radicals with one to ten carbon atoms per Zn(CH11O2)2 (zinc laurate), Zn(MnO4)2?8H2O (zinc radical, e.g., Al(OCH)3 (aluminum isopropylate or iso permanganate), Zn(NO3)2.3H2O (zinc nitrate), ZnN propoxide). 35 (zinc nitride), ZnO (zinc oxide), Zn(CHO) (zinc Likewise, there may be employed, not by way of lim acetylacetonate), Zn(C4H5O4)2 (zinc 1-phenol-4-sulfo itation, aluminum compounds containing other organic nate, Zn3(PO4)2 (zinc ortho phosphate), w radicals such as hydrocarbons, e.g. paraffins, cycloparaf Zn3(PO4)2.4H2O fins, olefins, acetylenes, aromatics, alcohols, phenols, ?ng(???)2-8?,? , Zns ????)2-2?2? , Zn2PO (zinc pyro ethers, carbonyls, amines, and benzene rings. Further 40 phosphate), Zn2P (zinc phosphide), Zn(HPOHO more, there may be used alloys of aluminum providing (zinc hypophosphite), zinc picrate, Zn(CH5O)2.3H2O such alloys are capable of being oxidized. It may in some (zinc salicylate), ZnSeO4.5H2O (zinc selenate), instances be necessary to use particular alloys in a finely divided state, e.g., of a particle size below 3.0 microns, ZnCO4 (zinc oxalate),ZnCO2HO zinc oleate, ZnSiO, (zinc meta... " in order to enhance oxidation. silicate), zinc stearate, ZnSO, (zinc sulfate) hydrates of Specific sources of zirconium include, not by way of 45 Zinc sulfate, ZnS, ZnSHO, ZnSO (zinc sulfite). Like limitation, metallic zirconium, organic and inorganic Wise, zinc alloys may be used. .? compounds containing zirconium including oxides, hy The cadmium ion source can be elemental cadmium droxides, oxalates, nitrates, nitrides, sulfides, sulfates, or a cadmium compound, e.g., compounds similar to those halides, and oxyhalides such as ZrBri, ZrCl4, Zrfa, Zr, for zinc listed hereinbefore. Cadmium compounds thus Zr(OH), Zr• (NO3)4•5H?O, ZrO2, Zr(CO4)3•2Zr(OH) 50 comprise both organic and inorganic including (zirconium oxalate, basic), Zr(SO4)2•4H2O, Zr?l(OH)3 + 3H2O, ZrF(OH)3-3H2O, ZrBr(OH)3 + 3H2O Cd(C2H8O2)2 (cadmium acetate), ZrI(OH)3+3H2O, ZrOCl2" 8H2O, ZrOF2 – 8H2O Cd (BrO3)2.H2O, ?r?Br2• 8?9? - ZrO2.8H2O, and zirconium compounds containing one 55 CdCO, or more organic radicals, e.g., hydrocarbons, esters, ben Cd (ClO3)2HO, zene rings, alcohols, olefins, etc., as listed for aluminum. CdCl2, There may also be used alloys of zirconium, providing Cd (CN), ...... such alloys are capable of being oxidized. Such alloys CdS2O6'6H2O (cadmium dithionate), may necessarily have to be employed in a finely divided 60 CdFe (CN) s state as noted for the aluminum alloys. The zinc ion source can be metallic zinc or a zinc com pound. Examples, not by way of limitation, of zinc com pounds include both organic and inorganic compounds 65 CdI2, such as Zn(C2H8O3)2 (zinc acetate), Zn(C2H8O2)2H2O, Cd(CHsO3)2 (cadmium lactate), ZnAl2O4 (zinc aluminate), Zn(NH2)2 (zinc amide), Cd(NO3), Zn (C7H5O2)2 (zinc benzoate), 3ZnO•2B2O3 (zinc bo CdO, rate), Zn(BrO3)26H2O (zinc bromate), ZnBra (zinc bro Cd2O, mide), Zn(C4H7O2)2•2H2O (zinc butyrate), 70 CdSeO, CdSe, CdSO, (zinc caproate), ZnCO3 (zinc carbonate), CdSOHO, CdS, Zn(ClO3)2• 4H2O 75 Cdso, 3,356,456 3 7 KPF (potassium hexafluorophosphate), cadmium alkali metal halides such as KF (), CdCl4NHC1 and KF.2H2O, CdBr: 4KCl, KHF, Cd (COO) (cadmium oxalate), 5 KAu(CN), Cd(CH5O)2·H2O (cadmium salicylate), KBF4 (potassium fluoborate), KHPO (potassium mono hydrogen orthophosphite), as well as alloys of cadmium. KH2PO3 (potassium di hydrogen orthophosphite), The potassium ion source can be elemental potassium KHCH4O4 (potassium hydrogen phthalate), or a potassium compound. Examples, not by way of limi KCHNO (potassium picrate), tation, of potassium compounds include both organic and O KC12H8O4 (potassium piperate), inorganic compounds such as KCH5O2H2O (potassium propionate), KHCsH3Oa (potassium saccharate acid), KCHSO4 (potassium propyl sulfate), KOCHNOa-2H2O (potassium-m-nitrophen oxide or po KHCHO (potassium acid-d-saccharate), tassium-p-nitrophen oxide), 5 KCH5O (potassium salicylate), KHCHO CHsO4 (potassium hydrogen succinate), KC5H9O4 (potassium santoninate), K2SO4 (), KC18H350 (potassium stearate), KHSO4 (potassium hydrogen sulfate), K2C4H4O4.3H2O (potassium succinate), K2S2O (), KHCH4O4 (potassium hydrogen succinate), K2S2O8 (potassium peroxydisulfate), 20 KHCH4O2H2O, K2S (potassium monosulfide), KFSO (potassium fluosulfonate), KS-5H2O, KThFs 4H2O (potassium fluothorate), KHS (), KTiFs H2O (potassium fluotitanate), KS (potassium disulfide), KCHO2 (), K2S3H2O, 25 K2CHPOs (potassium glycerophosphate), KS (potassium trisulfide), KH (), KS (potassium tetrasulfide), KOH (), KS-2H2O, KIO (), KS5 (potassium pentasulfide), KIOa-HIOa (potassium acid iodate), KSO2H2O, 30 KIO3 • 2HIO3, KHSO, KIO4 (potassium metaperiodate), K2S3O5 (potassium pyrosulfite), KI, KCH4O6%H2O (potassium d-tartrate), KI3 (potassium triiodide), K2C4H4Os, KCl, KHCH4O6 (potassium hydrogen d-tartrate), 35 KCl3, KHATe06.3H2O (potassium orthotellurate), KF, KCS (potassium trithiocarbonate), KF3, KSCN (), KBr, K2S2O6 (potassium dithionate), KBr3, K2SOs (potassium trithionate), 40 KCHsO3"xH2O (potassium lactate), KS4O6 (potassium tetrathionate), KC12H23O2 (potassium laurate), 2K2SO3H2O (potassium pentathionate), KaCHOs (potassium malate), KSnS 3?,?, K2CH2(SO3)2 (potassium methionate), 3K2S2O3.H2O (potassium thiosulfate), 2KCHSO4H2O (potassium methyl sulfate), 3K2SO o 5HO, KC10Hs (SO3)2 2?2? (potassium naphthalene-1,5- KHCH3NOa (potassium acid urate), disulfonate), KCHO (), KIBr2 (potassium dibromoiodide), KCH3OHCH3O (potassium acid acetate), K2SnBre KCHO-2H2O (potassium acetylsalicylate), K2C10H14O4.5H2O (potassium d-camphorate), KNH2 (), 50 K2CO3 (), KNHCHO (potassium ammonium tartrate), K2CO3"xH2O, KAuOxH2O, KHCO3 (potassium hydrogen carbonate), KN (), K2C2O8 (potassium peroxy-carbonate), KCHsO3.H2O (potassium benzoate), (KCO)6 (potassium carbonyl), K2B2H6 (potassium diborane), 55 KClO3 (), K2B2H6O2 (potassium dihydroxy diborane), KClO4 (), K2B5Hg (potassium pentaborane), KClO, KBO (potassium metaborate), KICA (potassium chloroiodate), KBO 8H2O (potassium tetraborate), KICl2, KBSO 4H2O (potassium pentaborate), 60 K2OSCls (potassium chloroosmate), KBO/2H2O (potassium peroxyborate), K2RhCls (potassium pentachlorohodite), KCHBO (potassium borotartrate), K2CrO4 (), KBrO (), K2Cr2O (), KBr (), K3CrOs (potassium peroxychromate), KAuBr, 65 KNO3 (), KCrO2Cr(OH) CrO (potassium chromium chromate, KN (), basic), KNO2 (), KCr(SO4)2' 12H2O (potassium chromium sulfate), KC18H38O2 (potassium oleate), KC6H5OHO (potassium citrate), KC18H33OaClaH34Oa (potassium acid oleate), KH2C6H5O7 (potassium citrate, monobasic), 70 K2OsO4.2H2O (potassium osmate), KOCN (), K2C2O4H2O (potassium oxalate), KCN (), KHC2O4 (potassium hydrogen oxalate), KC2H5SO4 (potassium ethyl sulfate), KHCO, 4HO, K2GeF6 (potassium fiuogermanate), ???2??•?,?, K2C20H10Os (potassium fluorescein derivative), 3,356,456 9. 10 K2O, Specific sources of sodium or lithium ion would include elemental sodium and lithium as well as compounds of all the classes listed for potassium, cesium, and rubidium KO2, hereinbefore, particularly the halides and oxides. KCH5SO4 (potassium phenyl sulfate), Likewise, alloys or ceramics containing one or more of KPO the Group A elements may be employed, particularly KHPO, where such alloy or ceramic is in a finely divided state. KPO3H2O (potassium pyrophosphate), Specific sources of the Group IIA metals include the KPO3. metals in an elemental state as well as organic and in Likewise, the corresponding compounds of other alkali O organic compounds including the acetates, amides, borides, metals such as sodium and lithium as well as cesium and bromates, halides (including chlorides, iodides, bromides, rubidium may be used as sources of the respective ion, fluorides), oxyhalides, carbonates, chlorates, chromates, e.g., sodium, lithium, cesium, and rubidium. citrates, hydrides, sulfides, sulfates, hypochlorites, nitrates, Thus, the cesium ion source can be elemental cesium nitrites, oxides, silicates, aluminates of beryllium, mag or a cesium compound similar to the K compounds noted nesium, calcium, barium, and strontium. Alloys may also hereinbefore. Examples, not by way of limitation of be employed as noted for the Group IB metals. cesium compounds, include both organic and inorganic Sources of the Group IB metals, copper and silver, compounds as CsC2H8O2 (cesium acetate), CsCH5Oa include the metals in elemental state, alloys, organic and (cesium benzoate), Csbros (cesium bromate), CsBr inorganic compounds including the hydrides, nitrides, (cesium monobromide), CsBr3 (cesium tribromide), 20 peroxides, suboxides, acetates, halides, sulfates, sulfides, CsBrCII (cesium bromochloroiodide), CsIBr2 (cesium di bromates, esters, and nitrates such as CU(C2H8O2)2 bromoiodide), CsI2Br (cesium bromodiiodide), Cs2CO3 (cupric acetate), CuCl22NHCl2.H2O (cupric ammo (cesium carbonate), CsPCO3 (cesium carbonate hydro nium chloride), CuSO4'4NH3H2O, Cu(BrO3)2' 6H2O, gen), CsClO3 (cesium chlorate), CsClO4 (cesium per Cu3B2, Cu2H2, Cu3N, CuOHO, Cua?, CuCl, Cu2Cl2, chlorate), CsCl (cesium chloride), CSAuCl4 (cesium chlo 25 CuBr, CugBr, CuI, Cu22, CuF, Cu2F2, CuSCN, roaurate), CsbrCl (cesium chlorodibromide), CsBrCl2 (C6H5COO)Cu2H2O (copper benzate) and AgNO2, (cesium dichlorobromide), CsCl (cesium dichloro Ag2O, AgCl, AgBr, AgI, AgF, AgBrO3, CH3COOAg iodide), Cs2SnCls (cesium chlorostannate), Cs2CrO4 (silver acetate), AgCr2O, KAg(CN)2, and silver phenol (cesium chromate), CsCn (cesium cyanide), CsP (cesium sulfonate. fluoride), CsCHO2 (cesium formate), CsCHO-H2O, CsH 30 Specific silicon compounds include, not by way of (cesium hydride), CsOH (cesium hydroxide), CsIO3 limitation, metal silicon, organic and inorganic compounds (cesium iodate), CsIO4 (cesium metaperiodate), CsI such as the silicon hydrides or silanes such as SiH4 (mono (cesium monoiodide), CSI3 (cesium triiodide), CSIs (ce silane), SigHs (disilane). SiaHg (trisilane), Si4H10 (tetra sium pentaiodide), CsCls, CSBr5, CSF5, CSNO3 (ce silane), Si6H12 (pentasilane), Si6H14 (hexasilane), SiH16, sium nitrate), CsNO'HNO3 (cesium hydrogen nitrate), 35 Si?Hu?, SigH20, Sidh2: alkylsilanes such as CHSiHa CsNO-2HNO (cesium dihydrogen nitrate), CsNO2 (monomethylsilane), (CH3)2SiHa (dimethylsilane), (cesium nitrite), Cs2C2O4 (cesium oxalate), CS2O (ce seium monoxide), Cs2O2 cesium peroxide), Cs2O3 (cesium trioxide), CsO2 (cesium superoxide), CSHCaH4O4 (ce (trimethylsilane), C2H5SiH3 (monoethylsilane), sium hydrogen phthalate), CsRh(SO4)2*12H2O (cesium 40 rhodium sulfate), CsCH5O3 (cesium salicylate), Cs2SO4 (cesium sulfate), CshSO4 (cesium hydrogen Sulfate), (diethylsilane), (CH3)3SiH (triethylsillane), (CH3)3Si Cs.S. 4HO (cesium sulfide), Cs2S (cesium disulfide), (silicon tetramethyl), (C2H)4Si (silicon tetraethyl), Cs2S2·H2O, Cs2S3 (cesium tetrasulfide), Cs2S5 (cesium (CH) SiH3, (CH)2SiH2, (CH)3SiH pentasulfide), Cs2S6 (cesium hexasulfide). The rubidium ion source can be elemental rubidium (CH)4Si (silicon tetrapropyl), C4HgSiH3, (C4Hg)2SiH2, or a rubidium compound, e.g., similar to the potassium (CAHg)SiH, (C4H9) Si (silicon tetrabutyl), C5H11SiH, and cesium compounds noted hereinbefore. Examples, not (C5H11)2SiH2, (C5H11)3SiH, (C5H11) Si (silicon tetraiso by way of limitation of rubidium compounds, include amyl), (C6H13SiH3, (C6H13)2SiH2, (C6H13)3SiH, both organic and inorganic compounds such as RbC2H8O2 50 (rubidium acetate), RbAl(SO4)2-12H2O (rubidium alu minum sulfate), RbBrO3 (rubidium bromate), RbBr (rubidium bromide), ... RbBrs (rubidium tribromide), (C6H5)4Si (silicon tetraphenyl), RbIBrCl (rubidium bromochloroiodide), RbIBr2. (ru-º. (CH)4Si (silicon tetra-m-tolyl or tetra-p-tolyl) bidium dibromoiodide), RbBrCl2 (rubidium dichlorobro (CHCH2)4Si (silicon tetrabenzyl), 9 mide), RbBrCl (rubidium : chlorodibromide), Rb2CO3 (C12H9)4Si (silicon tetraxenyl) s ?? (rubidium carbonate), RbHCO3, RbClO3 (rubidium chlo (CH3)3CH5Si (trimethylphenylsilane), rate), RbClO4 (rubidium perchlorate), RbCl, (rubidium (CH3)2(C6H5)2Si (dimethyldiphenylsilane), chloride), RbICl3 (rubidium dichloroiodide), Rb2CrO4 60 CH3(C6H5)3Si (methyltriphenylsilane), (rubidium chromate), Rb2Cr2O7 (rubidium dichromate), (CH3)3CHSi (triethyliphenylsillane), a RbF (rubidium fluoride), Rb2SiF6 (rubidium fluosilicate), (C2H5)2(C6H5)2Si (diethyldiphenylsilane), RbFSO (rubidium fiuosulfonate), RbH (rubidium hy C2H5 (CH3)3Si (ethylltriphenylsillane), dride), RbOH (rubidium hydroxide), RbO3 (rubidium (CH3) (C2H5) (n-C3H7) (C6H5) Simethylethylpropyl Y iodate), RbIO4 (rubidium metaperiodate)3, RbII (rubid 65 phenylsilaine), ium iodide), Rb1 (rubidium triiodide), Rb14SO2, (CH5) (n-CH) (i-C4Hg (CH2CH5) Si (ethyl-n-propyl-i- RbMnO4 (rubidium permanganate), RbNO3 (rubidium butylbenzylsilane), nitrate), RbNO3·HNO3 (rubidium hydrogen i nitrate), (CH3)3SiH (triphenylsillane), RbNO3•2HNO3, Rb2O (rubidium monoxide), Rb2O3, (C6H5CH3)3SiH (tribenzylsillane); Rb4O6 (rubidium trioxide), RbO2 (rubidium superoxide), s 70 Rb2SO4 (rubidium sulfate), RbHSO4 (rubidium hydro organosilicon halides or alkylhalosilanes such as gen sulfate), RbaS (rubidium monosulfide), RbaS-4HaO, CHSiHCl, CHSiHCl2, CHSiCls, CHCISiHa RbS (rubidium disulfide), Rb2S3 (rubidium trisulfide), CHCl2SiH, CCSiH, CHCl2SiHCl, CHCISiHCl RbS (rubidium pentasulfide), Rb2Ss (rubidium hexa CHClSiHaCl, C2H5SiHCl, C2H5SiHCl2, CHSiCl3 sulfide), RbHCHOs, Rb,02 (rubidium peroxide). ·75 CHSiHaCl, CHSiHCl2, CHSiCl3;

3,356,456 13 14 (C6H5)2SiCl2 (diphenyldichlorosilane), º (p-BrC6H4)2SiCl2 (di-p-bromophenyldichlorosilane), Likewise, one or more compounds may be employed (C6H5)2SiBr2 (diphenyldibromosilane), as a source of one or more additives, for example, (p-CHt)2SiCl2 (di-p-tolyldichlorosilane), Al(SiF) (aluminum silicofluoride), CSAl(SO4)2' 12H2O (C6H5CH2)2SiCl (dibenzyldichlorosilane), (cesium aluminum sulfate), KAgBr, KAg(CN)2, KSiF6 (CH2=CH)(CH3)SiCl (vinylmethyldichlorosilane), (potassium fluosilicate), K2SiO3 (potassium metasilicate), (CH2=CHCH2)(CH3) SiCl2 (allylmethyldichlorosilane), K2Si2O5 (potassium disilicate), KHSi2O5 (potassium hy CH5 (n-CH-) Si:Cl2, (ethylipropyldichlorosilaine), drogen disilicate), KZrF6 (potassium fluozirconate), CH; (ii-CH3) Si:Cl (ethyllisobutyldichlorosilaine), KCl CaCl (potassium calcium chloride), CsSiFs (cesium CH5 (C6H5)SiCl2 (ethylphenyldichlorosilaine), fluosilicate), AlgTi2, AlCl3%ZnCl2, AlCu, AlCu3, Al2Cu, CH(C6H5CH2) SiCl2 (ethylbenzyldichlorosilane), 0 CaZn, CaSiO, CaSi, CaAgCN, CdSiO3, and CaHis (C6H5 CH2) SiCla (phenylbenzyldichlorosilaine), CH5 (p-BrCH) SiCl2 (phenyl-p-bromophenyldichloro Furthermore, there may be employed alloys contain silane), ing one or more of the aforementioned additives, such CHSiCl3 (methyltrichlorosilane), 15 as Ag-Cu alloys, particularly an alloy containing 80% C2H6Si:Cl3 (ethylltrichlorosilaine), Ag-20% Cu, by weight. CH2=CH-SiCl3 (vinyltrichlorosilane), Among the above sources listed for aluminum, zir n-C3H7SiCl3 (propyltrichlorosilane), conium, the metallic members of Groups LA, IB, IIA, CH=CHCH2SiCl3 (allyltrichlorosilane), and IIB, and silicon, there are certain advantages which n-CHSiCl3 (butyltrichlorosilane), 20 will accrue from the use of certain classes of material, i-C4HgSiCl3 (isobutyltrichlorosilane), for example, the halides, particularly the chlorides. i-C5H1SiCl3 (isoamyltrichlorosilane), It is particularly advantageous to conduct the vapor C6H5SiCla (phenylltrichlorosilane), phase oxidation in the presence of sources which will CHSiCl3 (cyclohexyltrichlorosilane), react with oxygen at the temperature of the vapor phase p-CHSiCl3 (p-tolyltrichlorosilane), 25 oxidation to form the corresponding metal oxide. It is CsH5CH2SiCl3 (benzyltrichlorosilane), not intended to indicate that the source materials herein a-CoHSiCl3 (a-naphthyltrichlorosilane), listed for aluminum, zirconium, silicon and the mem CHSiBrs (methyltribromosilane), V bers of Groups IA, IB, IIA, IIB must actually form the (CH3)3SiOH, (CH3)6Si2 (hexamethyldisilane), corresponding metal oxide during the vapor phase oxida (C2H5)6Si2 (hexaethyldisilane), 30 tion. However, it is advantageous if the source material (CH)6Si2 (hexa-n-propyldisilane), - in this instance is capable of forming a metal oxide, (C2H5)2(CH)2(C6H5)2Si2 (diethyldipropyldiphenyldi regardless of whether such oxide is formed. silane), Where a metallic source is a high ionizable salt such (C2H5) 20CH) 2 (C?H? ) 2Si2 (diethyldipropyldibenzyldi as-KC, NaCl, LiCl, BeCl2, RbCl, CsCl, it is not neces silane), 35 sary for such compound to be capable of forming an (C6H5)3Si2 (hexaphenyldisillane), oxide at the vapor phase oxidation temperature; that is, (CH)6Si2 (hexa-p-tolyldisilane or hexabenzyldisilane), good results are obtained by the addition of a highly -(CH)8Si- (octaphenyltetrasilane), ionizable source which is not oxidized at the reaction (C6H5)2Sila (cyclooctaphenyltetrasilane), temperature and which remains substantially unchanged -(CH)3Si4- (octa-p-tolyltetrasilane), 40 chemically, e.g., as analyzed in an effluent stream from (p-CH)2Sila (cycloocta-p-tolyltetrasilane), the reactor. Thus, when KCl is added to the vapor phase (C3H7)6Si2O (hexapropyldisiloxane), reaction of TiCl, and O, it is not oxidized but may be (C2H5)3Si2O (hexaethyldisiloxane, recovered as KC). (CH3)3Si2NH (hexamethyldisilazane, Furthermore, it is also feasible to employ sources which (CH3)3Si2O (hexamethyldisiloxane), are not highly ionizable and which do not form oxides (CH)3Si4O2 (cyclooctaphenyltetrasilane oxide or di at the vapor phase oxidation temperature particularly if oxide), . . . . . such sources are heated to a high temperature by passage through a plasma arc, e.g., in the presence of an inert siloXane), gas or one of the reactants such as oxygen. (C6H5)3Si2O (hexaphenyldisiloxane), : 50 The sources listed hereinbefore may be introduced into (CH)6Si2O (hexa-p-tolyldisiloxane), . the reaction chamber 30 very effectively as solutions in a (CH3)2(C6H5)4Si2O (dimethyltetraphenyldisiloxane), solvent, e.g., in the form of a spray. Thus, water soluble (C2H5)2(C6H5)Si2O (diethyltetraphenyldisiloxane), metal sources of the type herein contemplated can be (C2H5)2(n-C8H)2Si2O (diethyldipropyldibenzyldi- . used in water solutions. Oganic, metal sources may be : siloxane, s: ... ..?? : *.*? :: used in many cases where they are liquids or gases, or may be used in solutions in common organic solvents disiloxane), which are not adverse to the vapor phase oxidation. (C6H5)4Si2O(OH)2 (tetraphenyldisiloxane-1,3-diol), Typical solvents are chloroform, methylene chloride, (C6H5)SiO2(OH)2 (hexaphenyltrisiloxane-1,5-diol), or like chlorinated aliphatic or aromatic solvents: Other (CH5)(CH3)2SiO(OH), (diethyldiphenyldisiloxane 60 typical solvents include acetones, ketones, benzenes, and ... 1,3-diol), ...... alcohols. ". ... (CH)SiO(OH)2 (tetrabenzyldisiloxane-1,3-diol), It is also advantageous to use materials which vaporize " (C7H)4Si3O2(OH)2 (hexabenzyltrisiloxane-1,5-diol), readily and can be introduced in a vapor state. Thus, (Me2SiO) (hexamethylcyclotrisiloxane), zinc metals and various zinc halides are advantageous (Et2SiO) (hexaethylcyclotrisiloxane), , , (C6H5)6SiO (hexaphenylcyclotrisiloxane), 65, which are volatile at the vapor phase reaction temper (C6H5)3SiO4 (octaphenylcyclotetrasiloxane), The following is a typical working example representing - (C7H7)6Si3O3 (hexabenzylcyclotrisiloxane), i. the best mode contemplated by the inventor in the carry (EtBzSiO) (triethyltribenzylcyclotrisiloxane). , ing out of this invention. In addition, applicant incorporates herein by reference 70 ... Example all of the silicon compounds listed on pages 166 to 195 A burner having the configuration of burner B in FIG of "Silicones and . Other Organic Silicon Compounds,” URE 3 is employed in conjunction with reaction chamber by Howard W. Post, Reinhold Publishing Corporation, A of FIGURE 1. New York (1949). tr. r. ? ? - ? - ? - ? ? ... 75 --Titanium tetrachloride. (TiCl) at 1000 C. and 14.7 3,356,456 15 16 pounds per square inch absolute pressure is flowed at the Conversely, the more brown the pigment, the less pleasing rate of 80 millimoles per minute through annulus 17 into the optical properties of the paint. reaction zone 30. The TiCl, contains 3 mole percent of The undertone scale to be used ranges from a Brown AlCls based on the total moles of TiCl4. 10 to a Blue 6 as shown hereinafter in Table II. Simultaneously, oxygen at 1000 C. and 14.7 pounds 5 TABLE III illi eekuuuyyuyyyyyyuuuuo ySZu kmyS Brownkkk 9k BrownNeutral 1 reaction zone 30. Brown 8 Blue 1 A 40 mole percent chlorined shroud (based on the total Brown 7 Blue 2 (Standard) moles of TiCl4) at 1000 C. and 14.7 pounds per square 10 Brown 6 Blue 3 inch absolute pressure is flowed through annulus 16. Brown 5 Blue 4 1000°The C.reaction zone 30 is preheated and maintained at Brown 4 Blue??????? ????5 Varying amounts of different ions from Groups IA, ;'; i IB, IIA, IIB are added to the oxygen stream. The AlCls 15 addition to the TiCl, is held constant at 3 mole percent. While the invention has been described by reference All ions were added as chlorides, e.g., KCl, CsCl, RbCl, to specific details of certain embodiments, it is not in BaCl2, BeCl2, AgCl, ZnCl2 and SiCl4. tended that the invention be construed as limited to such The titanium oxide pigment formed in zone 30 is with- details except insofar as they appear in the appended drawn at exit 7 entrained in a gaseous effluent stream. 20 claims. The raw pigment is recovered and is wet coated with I claim: hydrous alumina and titania in accordance with the proc- 1. A process of preparing pigmentary titanium oxide, ess of U.S. Letters Patent 3,146,119 issued to Dr. Hartien which comprises reacting a titanium tetrahalide selected S. Ritter. from the group consisting of titanium tetrachloride, The results are tabulated in Table I. All additives are 25 titanium tetrabromide, and titanium tetraiodide with an expressed in parts by weight of the particular metallic oxygenating gas in the vapor phase in the presence of an ion per million parts by weight titanium oxide pigment effective amount of at least one rutile promoting agent, formed. an effective amount of zinc ion, an effective amount of Both raw and coated tinting strength (T.S.) are given a metallic ion selected from the metals of Groups IA, for the pigment, as well as raw and uncoated tint tone 30 IB, and IIA, and cadmium, and an effective amount of (T.T.). a source of silicon ion.

TABLE RüI Additives to 0 p.p.m. Pigment, Pigment, Pigment, Pigment, No. Titanium. Oxide Raw Coated Raw Coated T.S. T.S. ?.?. T.T.

None------1,500 1,550 Brown 10. Brown 4. 4,000Zn, 100K.- 1,720 1,820 Blue ------Blue 3. 3,000Zn, 50.K.-- 1,710 1,800 Blue 2.-- D0. ? 3,500 Zn, 100 K.-- 1,710 1,810 Blue 1.- Do. 3, 500 Zn, l,000 Cs 1,690 1,780 Brown 1 Blue 2 2,000 Rb, 100 K.- 1,700 1,790 Neutral Blue 3 2,000 Rb, 1,000 Cs-- 1,700 1,780 2,000 Cs, 100 K.------1,710 1,790 Blue1------w 4,000 Zn, 100 K, 2,000 Si---- 1, 750 1,850, Blue 2.------Blue 5 4,000 Zn, 3,000 Ba.-- - 1,690 1, 750 Brown 2. Blue 1 4,000?Zn, 3,000 Be-- 1,700 1,760 Neutral. Blue 2 4,000 Zn, 2,500 Ag —------1,700 1,760 ---do-- Blue 4,000 Zn, 3,000 Be, 2,500 Si. 1,710 1,780 Blue -- Blue 3 4,000°Zm, 2,500 Ag, 2,500 Si 1,710 1,770 -----do-- Blue 2

The tinting strength of pigmentary titanium dioxide 2. A process according to claim 1 wherein said metallic may be determined by any of several methods known in ion is potassium ion. the paint industry. One such method is the Reynold's Blue 3. A process according to claim wherein said rutile Method, A.S.T.M. D-332-26, “1949 Book of A.S.T.M. promoting agent is a source of aluminum ion. Standards,” part 4, page 31, published by American 55 4. A process according to claim 1 wherein the total Society for Testing Material, Philadelphia 3, Pennsyl amount of rutile promoting agent and other metallic ions vania. does not exceed 10 weight percent, basis titanium oxide Tint tone or undertone of a titanium dioxide pigment formed. sample is determined by visuually comparing a paste of 5. A process of preparing pigmentary titanium oxide the pigment with a paste of a selected standard. 60 having improved pigmentary properties, which comprises In the example hereinbefore, a paste of a sample from reacting a titanium tetrahalide selected from the group each run, and a paste of a standard is. prepared in ac consisting of titanium tetrachloride, titanium tetra cordance with A.S.T.M. D-332-36 using carbon black bromide, and titanium tetraiodide with an oxygenating to tint each sample paste to the same depth of grey as gas in the vapor phase at a temperature of at least 800 the standard. 65 C. in the presence of: The standard used has an oil absorption rating of 20.9 (a) from 0.5 to 10.0 mole percent, basis moles of as determined by A.S.T.M. D-281-31, an average par titanium oxide, of a metal ion selected from the ticle size of 0.25 micron as determined with an electron group consisting of aluminum and zirconium ion, micrograph, and an assigned undertone value of Blue 2. (b) from 0.01 to 10,000 parts, per million parts of The samples obtained from the runs in the example are 70 titanium oxide, of zinc ion, compared with the standard and an undertone value (c). from 0.01 to 10,000 parts, per million parts of assigned to the sample by stating, whether the sample is titanium oxide, of a metallic ion selected from the bluer or browner than the designated Standard. metals of Groups IA, IB, and IIA, and cadmium, and The more blue a pigment is, the more pleasing are the (d) from 0.001 to 2.7 mole percent, basis moles of optical properties of a paint prepared from the pigment. 75 titanium oxide, of silicon ion. 3,356,456 17 18 6. A process according to claim 5 wherein said metallic prises reacting titanium tetrachloride with oxygen in the ion selected from the metals of Groups LA, IB, and IIA, vapor phase at a temperature of at least 800° C. in the and cadmium is potassium ion. presence of 3 mole percent of aluminum chloride, basis 7. A process of preparing pigmentary titanium oxide titanium oxide, 4,000 parts per million parts of titanium which comprises reacting a titanium tetrahalide selected oxide of zinc ion, 100 parts per million parts of titanium from the group consisting of titanium tetrachloride, tita oxide of potassium ion, and 2,000 parts per million parts nium tetrabromide, and titanium tetraiodide with oxygen of titanium oxide of silicon ion. in the vapor phase at a temperature of at least 800° C. 12. In a process of preparing pigmentary titanium oxide in the presence of: wherein a titanium tetrahalide selected from the group (a) from 0.5 to 10.0 mole percent, basis moles of tita 10 consisting of titanium tetrachloride, titanium tetrabromide, nium oxide, of a metal ion selected from the group and titanium tetraiodide is reacted in the vapor phase at consisting of aluminum and zirconium ion, a temperature of at least 800° C. with oxygen, the im (b) from 5 to 5,000 parts, per million parts by weight provement which comprises carrying out said reaction in titanium oxide, of zinc ion, the combined presence of: (c) from 5 to 5,000 parts, per million parts by weight 15 (a) from 0.5 to 10.0 mole percent, basis moles of tita titanium oxide, of potassium ion, and nium oxide, of a metal ion selected from the group (d) from 0.01 to 2 mole percent, basis moles of tita consisting of aluminum and zirconium ion, nium oxide, of silicon ion; such that the total amount of (b) from 0.01 to 10,000 parts, per million parts of said metallic ions does not exceed 10 weight percent, titanium oxide, of metallic zinc ion, basis titanium oxide formed. 20 (c) from 0.01 to 10,000 parts, per million parts of 8. A process according to claim 7 wherein the total titanium oxide, of a metallic ion selected from the amount of metallic ions does not exceed 4.0 weight per metals of Groups IA, IB, and IIA, and cadmium, and cent, basis titanium oxide formed. (d) from 0.001 to 2.7 mole percent, basis moles of 9. A process of preparing pigmentary titanium oxide titanium oxide, of silicon ion. of improved tinting strength and tint tone which com 25 prises reacting titanium tetrachloride with oxygen in the References Cited vapor phase at a temperature of at least 800° C. in the presence of 0.5 to 3.0 mole percent, basis titanium oxide, UNITED STATES PATENTS of aluminum chloride, 5 to 5,000 parts per million parts 2,957,753 10/1960 Nelson et al. ------23-202 titanium oxide of potassium ion, 5 to 5,000 parts per 30 2,980,509 4/1961 Frey ?------?---- 23-202 million parts titanium oxide, of zinc ion, and from 0.2 to 3,068,113 12/1962 Strain et al. ------23-202 1.2 mole percent, basis titanium oxide, of silicon ion. 3,208,866 9/1965 Lewis et al. ------23-202 X 10. A process according to claim 9 wherein the source 3,214,284 10/1965 Wilson ------106-300 of potassium, zinc, and silicon are their respective chlo rides. 35 OSCAR R. VERTIZ, Primary Examiner. 11. A process of preparing pigmentary titanium oxide of improved tinting strength and tint tone which com EDWARD STERN, MILTON WEISSMAN, Examiners.