2,754,256 United States Patent Patented July 10, 1956

2 is convenient, economical and adaptable to commercial 2,754,256 production. A still further object of the invention is to provide a PROCESS FOR PG superior method for removing a major portion of the TETRACHLORIDE impurities from crude titanium tetrachloride in a manner Edge] P. Stambaugll, Metuchen, N. J., assignor to Na such that no polymerization occurs and the residue formed tional Lead Company, New York, N. Y., a corporation may be readily removed from the still. of New Jersey These and other objects will become more apparent from the following more complete description of the No Drawing. Application April 24, 1953, 10 instant invention. Serial No. 351,028 In its broadest aspects the present invention relates to 9 Claims. (Cl. 202—57) a process for producing substantially pure liquid titanium tetrachloride by admixing crude titanium tetrachloride and a liquid chlorinated hydrocarbon of the methane The present invention relates in general to the prepara 15 series containing at least 5 atoms and at least one tion of the tetrahalides of metals of the fourth group of atom per molecule and heating the mixture from elements and more especially to the puri?cation of tita 65° C. to of said mixture and separating the nium tetrachloride and similar stable normally liquid dis puri?ed titanium tetrachloride therefrom. tillable tetrahalides. As used herein, the term “Chlorinated hydrocarbons of In general the tetrahalides of metals of the fourth group 20 the methane series” includes all saturated hydrocarbons of elements are prepared by chlorinating a metal-bearing having at least 5 carbon atoms per molecule and chlorin material and recovering the metal from the tetrachloride ated para?ins including polyvinyl . Only the vapor in the form of a relatively impure liquid conden chlorinated hydrocarbons of the methane series which sate. By way of example, liquid titanium tetrachloride are liquid at room temperature are contemplated by the is commonly prepared by treating a titaniferous material 25 instant invention. The purifying agent must contain at such as titaniferous iron ore, or with chlorine least 5 carbon atoms and at least 1 chlorine atom per gas, in a static bed or lino-solids operation, to form tita molecule. Those compounds which are most satisfactory nium tetrachloride vapor which is subsequently condensed for puri?cation and which are liquid usually contain from to form a crude titanium tetrachloride condensate. Since about 5% to about 60% chlorine by weight. These liquid there are a number of elements in the raw material, in chlorinated hydrocarbons are saturated and therefore con addition to titanium, which react with chlorine to form tain no double or triple bonds. These saturated com volatile chlorides and which carry over with the titanium pounds therefore do not polymerize in the titanium tetra tetrachloride vapors, the titanium tetrachloride conden and therefore are desirable as a purifying agent. sate, sometimes hereinafter referred to as crude titanium The treatment of crude titanium tetrachloride, by which tetrachloride, is invariably impure. Moreover, it has is meant a liquid titanium tetrachloride containing such been found that these volatile chlorides are not readily impurities as vanadium, silica, alumina, niobium, tungsten eliminated by since the respective chlorides and the like, with chlorinated hydrocarbons may be car— such as, for example, the chlorides of silicon, aluminum, ried out, according to the present invention, in any con~ niobium, tungsten and vanadium, tend to distill over with venient manner which will insure the required intimacy the titanium tetrachloride values and to be found in the of contact between the crude titanium tetrachloride and condensate. One such impurity which, because of the the purifying agent. The puri?cation treatment may be proximity of its boiling point to that of titanium tetra carried out in a puri?cation unit comprising, for example, chloride, cannot be separated therefrom by fractional a still having a fractionating column, a re?ux return and distillation is vanadium chloride. Vanadium chloride is a condenser, by heating the crude titanium tetrachloride present in substantially all crude titanium tetrachloride with a chlorinated hydrocarbon in the still at a tempera condensate and comprises a major portion of the impuri ture from 65° C. to boiling point of the mixture and there ties in the condensate and hence is chie?y responsible for after separating the treated titanium tetrachloride by dis the yellowish color of crude titanium tetrachloride. By tilling and condensing the puri?ed titanium tetrachloride. way of example, a typical crude titanium tetrachloride The puri?cation treatment may also be carried out in a may comprise from 0.25 to 0.35% vanadium based on 50 vessel by heating the mixture at a temperature between the weight of the titanium tetrachloride, the other impuri 65° C. and the boiling point of the mixture and ?ltering ties being present in relatively small amounts such as, for the heat-treated mixture to obtain the puri?ed titanium example, from 0.04 to 0.2% silica, from 0.02 to 0.025% tetrachloride as the ?ltrate. In using liquid chlorinated . alumina, from 0.01 to 0.02% niobium, and from 0.05 to hydrocarbons as puri?cation agents it has been found that 0.08% tungsten. 55 puri?ed titanium tetrachloride may be recovered from the While it has been proposed heretofore to purify crude mixture by either the distillation or ?ltration method titanium tetrachloride and other similar tetrahalides by described above. treatment with such materials as hydrogen sulphide, silica The chemical reaction which takes place between the. gel, carbon, salts of the heavy metals, soya bean oil, art purifying agent and the titanium tetrachloride is not com gum, etc., such methods have been characterized by the 60 pletely understood. The purifying agents contemplated formation of residues which have been either insoluble by the instant invention, that is, the liquid chlorinated or removable from the still bottoms only with the greatest hydrocarbons are apparently soluble in the titanium tetra difficulty. As a consequence the adaptation to commer chloride and only a very small residue or reaction product cial production of prior methods for purifying crude is formed. This residue, however, apparently is ?nely titanium tetrachloride have been attended by much di?i 65 divided and remains suspended in the titanium tetrachlo culty and high cost. ride during the heat treatment. An object of the present invention is, therefore, to The type of residue which forms in the instant inven provide a superior method for producing substantially tion is entirely different from that obtained when employ ing organic compounds which polymerize and form bulky I pure liquid tetrahalides of the fourth group of elements. A further object of the invention isto provide a superior 70 and sticky still bottoms which are dit?cult to handle. When the chlorinated hydrocarbons are employed, how , method for purifying crude titanium tetrachloride which ever, only very small amount of suspended residues are 2,754,256 '2 -. . ‘3 formed inthe ,still- , ,Thiscresidue. was held .il1...,SJ-l§Pen5_i9.n obtained which can be concentrated and ?ltered fromtime and did not form a stickyor bulky still bottom. The to time and therefore stillibottom difficulties are elimi residue when dried had a volume of less than 1% of the nated. The total amount of residue formed in the vessel total volume of the titanium tetrachloride used. is 'ii'siially'less than about 1% ‘of the total ‘volume of titanium tetrachloride used. Example 2 ‘The amount of chlorinated hydrocarbon used as a puri To 100 parts of the same crude titanium tetrachloride _ fying'ag'e'nt‘ is. dependent upon the amount of impurities at substantially ‘room temperature was added ‘051 'part ofv "and particularly the vamount of vanadium present in the chlorinated para?in containing 50% chlorine by weight ‘crude titanium tetrachloride and upon the time and tem whereupon the mixture was re?uxed at a temperature of perature of the treatment employed. It has been found 10 about 136°C. for a period of 15 minutes. The ‘treated vthatfro'rn'about 0.01% to about 1% should be employed mixture was then distilled and yielded a substantially pure to remove substantially all ofthe vanadium from the titaniumitetrachloride.H The vanadium content of the crude titanium tetrachloride. The amount of agent will pure titanium tetrachloride was 0.0003% V. ‘vary vaccording to the vanadium content present in the crude material. In 'most cases this amount will'vary Example 3 i'fr'o‘rh approximately 0.04 to 0.5% Vin the crude titanium The same procedure was used to purify crude titanium tetrachloride. The smaller amounts of purifying agent 'tetrachloride except that a polyvinyl chloride was used ‘may be'ernploye'd for purifying the crude titanium tetra and substantially identical results were obtained. chloride which contains the 'smaller'amounts of vana Example 4 dium. The smaller amounts, that is, below about 0.1% 20 ‘may be employed when the treatment is made at substan To 100 parts of‘the vsame crude titanium tetrachloride tially boiling temperatures. When operating at tempera were added 0.3 part of chlorinated para?n containing "tui‘es below boiling, it‘ is necessary to increase the amount 42% chlorine whereupon the mixture was heated to 120° of'purifying agent employed until the larger amounts are C. and held at that temperature for a period of' l‘hour. ‘used at the lower treatment temperatures. With respect The. solution'rwas then ?ltered and a substantially pure 'to "the time of treatment'it is necessary to lengthen the titanium tetrachloride ‘which contained 0.0003% V was 1time as lower temperature treatments are employed. For ' obtained'as the ?ltrate. ‘illustration purposes the following comparison is pre Example 5 sented. With a crude titanium tetrachloride which con tains 0.4% V, the time of treatment is only a few minutes .The'sa'me procedure as that described in Example 4 was ‘at the boiling temperature, approximately 1 hour ‘at 120° used except that 0.5 % of the purifying agent was employed 'C., 2 hours at 95° C., 3 hours at 85° C., and 12 to 18 and the mixture was heat-treated for 3 hours at 85° C. hours at'65° C. in this particular instance, the amount ‘Upon ?ltering, substantially identical results were'obtained. of “purifying agent was varied from .l% to 1.0%, as the Example '6 vtemperature was lowered in each successive. run. In the ‘case of treating a crude titanium tetrachloride which con Thei'pro'ce'dure used in Example 4 was followed ‘except T'ta'ins 0.04% vanadium, it was desirable to use purifying that 0.5% of the purifying agent was employedrand that ‘agents in amount of 0.01% to 0.1% as the temperature the ‘mixture was heat-treated at 65° C. for 18 hours. ‘of‘tr'eatment was lowered. In each of the above cases Again similar results were obtained upon ?ltration. 'the vanadium content in the puri?ed titanium tetrachlo 40 Example 7 iride’fell within the ‘range of from about 0.0001% to 0.'0003,% by weight of the titanium tetrachloride and the In this example the same procedure used in Example 1 remaining impurities in the titanium tetrachloride were was employed'except that 0.5% of dichloropentane was "present in such small quantities as to be innocuous. employed in‘ place of the chlorinated para?in. Again sub _ If the crude titanium tetrachloride contains consider stantially‘identical results to those described in'Example :able'a‘mount of sludge it is necessary toiadd somewhat 1 were obtained. more'of'the purifying agent than that described above. Example 8 V _ In carrying out the treatment'of the crude titanium tetra chloride with a liquid chlorinated'hydrocarbon the chlo The s'ame'procedure used in Example 1 was ‘employed rinated hydrocarbon is usually added to crude titanium ‘except that 0.5 %_ lauryl chloride, was used in placev of the tetrachloride at‘substantially room temperature where chlorinated paraf?n and substantially identical results ‘:upon'the mixture is heated to a temperature of from about were obtained. a ‘ v65" CT to the boiling'point of‘ the mixture for a period of Example 9 time ranging from a minute or two to about 20 hours, fdepeindingi‘upon the temperature of heat'treatment, after 55 Employing 0.5%‘ cetyl chloride in place of the chlorin ,whichihe'pure titanium tetrachloride is either distilled and ‘ ated paraffin again produced substantially identical’r'esults. :condensed or ?ltered from the mixture. For economical ‘By the process of this invention, crude titaniumitetr'a reasons a minimum amount of chlorinated hydrocarbon chloride which contained impurities, particularly pana ‘for v'e?ecting substantially complete puri?cation of the 'dium,, may be puri?ed by treating the crude titanium tetra crude titaniumtetrachloride is preferred._ However, as chloride in the presence ofa small ‘quantity of liquid‘chlo itlieiaiinlountfof purifying compound added to the crude rinated' hydrocarbon and a substantially pure titanium ‘titanium tetrachloride is increased ‘the time required for tetrachloride may be obtained. The heat treatment'may .heatlt'reating the admixture of crude titanium tetrachloride be carried out at temperaturesv from about 65° C. to the “and'the purifying agent is decreased. ' boiling'pointv of the mixture. .The puri?ed titanium tetra The following examples are illustrative. chloride maybe recovered'frorn the mixture by. either Example 1 distillation or ?ltration. Theprocess is simple: and'eco nomical to'operate and is particularlyadaptable for com-, 'TolOOO parts of crude titanium tetrachloride (contain mercialproduction. By employing the particular ‘type‘of ing 0.35% V) at substantially room temperature was purifying agent contemplated in the instantjinvention only ‘added 1 part of chlorinated parai?n containing 42%’chlo 70 a very small amount of residue is formed'and residue ride .by weight and the mixture was ‘re?uxed at a tem remains suspended in the titanium tetrachloride and apera'ture of.v about 136°;C. for a period of 15 minutes. ‘therefore does not present any'dif?culty in removal from ‘The’ treated mixture was then distilledanda substantially theystill, which vis a decidediimprovementg over residues .pure titanium, tetrachloride condensate was secured. The .5..wl;i¢h,f9rg1 rolamiaq?s. anisticky still ibgttqmsr Ilia‘: wanasliam Canter“. at the Pale iitaaium .tettachlaride?vas ‘ particular typés'of agent apparently‘do‘not form‘ ‘"0T.000?;%\ V. An‘extre'mely small amount ‘of residue was 7 2,754,256 5 6 and therefore do not result in bulky masses which are 3. Process according to claim 1 in which the puri?ed extremely di?icult to handle. The small amounts of titanium tetrachloride is removed by ?ltration. residues Which are formed by using liquid chlorinated 4. Process according to claim 1 in which the liquid hydrocarbons according to the instant invention and which chlorinated aliphatic hydrocarbon contains from about are suspended in the mixture may be removed with ease Cl 5% to about 60% chlorine by weight. by ?ltration or other convenient manner and the ?ltrates returned to the still if desired. Such methods of removal 5. Process according to claim 1 in which the chlorin are substantially impossible with bulky or sticky residues. ated aliphatic hydrocarbon is chlorinated para?in. 6. Process according to claim 1 in which the chlorin While this invention has been described and illustrated ated aliphatic hydrocarbon is polyvinyl chloride. by the examples shown, it is not intended that it be 7. Process according to claim 1 in which the chlorin limited thereto, and other modi?cations and variations ated aliphatic hydrocarbon is dichloropentane. may be employed within the scope of the following claims. 8. Process according to claim 1 in which the chlorin I claim: ated aliphatic hydrocarbon is lauryl chloride. 9. Process according to claim 1 in which the chlorin 1. Process for purifying crude titanium tetrachloride 15 by removing a major portion of the vanadium therefrom ated aliphatic hydrocarbon is cetyl chloride. which comprises admixing crude titanium tetrachloride and liquid chlorinated aliphatic hydrocarbon containing References Cited in the ?le of this patent at least 5 carbon atoms and at least 1 chlorine atom per UNITED STATES PATENTS molecule and subsequently heating the mixture of said 20 2,592,021 Frey et al ______Apr. 8, 1952 crude titanium tetrachloride and liquid chlorinated ali phatic hydrocarbon at a temperature of from about 65° OTHER REFERENCES C. to boiling point of said mixture and removing from said mixture the puri?ed titanium tetrachloride. Mellor’s “Inorg. and Theoretical Chem.,” vol. 7, 1927 2. Process according to claim 1 in which the puri?ed ed., page 82; Longmans, Green and Co., N. Y. 25 “Titanium” by I. Barksdale, 1949 ed., page 106; Ronald titanium tetrachloride is removed by distillation. Press Co., N. Y.