UNITED STATES PATENT OFFICE 2,102,737 PREPARATION of ANTMONY CHLORDES Ferdinand W
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Patented Dec. 21, 1937 2,102,737 UNITED STATES PATENT OFFICE 2,102,737 PREPARATION OF ANTMONY CHLORDES Ferdinand W. Peck, Penns Grove, N.J., and Wii liam R. Waldron, Wilmington, Del, assignors to E. I. du Pont de Neneurs & Company, Wil mington, Del, a corporation of Delaware No Drawing. Application February 28, 1934 Seria No. 13,400 10 Claims. (C. 23-98) This invention relates to antimony chlorides, move arsenic. It is also possible to produce anti more particularly antimony trichloride, and a mony trichloride by reacting together metallic proceSS for the production thereof. It further antimony and antimony pentachloride, but such relates to the preparation of antimony chloride a process is hazardous Since the reaction occurs 5 Solvent mixtures and to the production of flavan with almost explosive violence. throne from Such mixtures by condensation with One of the objects of this invention is the pro beta-amino-anthraquinone. vision of a new and improved process for the It is known that flavanthrone may be formed production of antimony trichloride from metallic by heating beta-amino-anthraquinone with anti antimony in an organic solvent. Another object O hony pentachloride. One such method involves is the production of antimony trichloride by a 10 heating the beta-amino-anthraquinone with process which is substantially non-corrosive, antimony pentachloride in nitrobenzene. An which avoids the formation of the antimony oxy other method involves the preparation of flavan chloride as a by-product, and in which the yields throne by heating beta-amino-anthraquinone of antimony trichloride are high. A further ob With antimony pentachloride to 160° C. Whereby ject is the preparation of solvent mixtures of an addition compound of the color with antimony antimony trichloride and antimony pentachloride penta chloride is formed, and then decomposing suitable for the production of flavanthrone in this addition compound to the color compound. high yields. A still further object is to provide The method of preparing the antimony penta a new and improved route to flavanthrone start chloride to be used in this condensation is an in ing with metallic antimony as one of the raw 20 portant factor, Since the yields of flavanthrone materials. Other objects will appear hereinafter. may vary Widely with different methods of pre These objects are accomplished by the follow paring the antimony pentachloride, either due to ing invention. Finely ground metallic antimony contamination by impurities or, in Some cases, is suspended in an organic solvent and while stir probably due to the lack of certainingredients ring to keep the antimony in suspension, chlorine 25 in the condensation process. is introduced until a large percentage of the me A number of processes have heretofore been tallic antimony is chlorinated to the trichloride. proposed for making antimony chlorides. One of After the desired amount of metallic antimony these processes consists in burning antimony in has been converted, the antimony chloride-solvent chorine, in this Way forming the penta, chloride mixture is preferably heated in the presence of: 30 30 directly. When the pentachloride is thus pro the excess of metallic antimony over that theo duced, however, it contains the chlorine addition retically required to convert any antimony penta product which is disastrous to a high yield of chloride Which may have been formed back to fia Vanthrone. the trichloride. Usually, the amount of anti Antimony trichloride may be prepared by treat mony pentachloride present is Small and is caused ing antimony With chlorine While maintaining by local over-chlorination. After the Small an excess of antimony at all times. It may be amount of pentachloride has been removed by prepared, also, by dissolving antimony oxide in this treatment, the liquid portion of the mixture, a large excess of concentrated hydrochloric acid, comprising Substantially the solvent. With the antimony trichloride dissolved therein, is sepa 40 40 but in doing this the oxychloride is always formed. On distillation, considerable proportions of the rated from the metallic antimony in any suit -trichloride distill with the Water and acid, and able manner, for example, by filtration or by there is also obtained an Oxychloride residue. decantation, and the liquid then purified, prefer This reaction is very corrosive and it is difficult ably by distillation either at atmospheric or at to find materials suitable for plant equipment. reduced pressures. Antimony trichloride may also be formed by If desired, the antimony trichloride may be the action of aqua, regia, on the metal. This proc recovered as such at this point, in which case ess has been modified by chlorinating a suspen it is most convenient to carry out the chlorina sion of antimony in 20% to 25% hydrochloric tion of the metallic antimony in a solvent, which acid. Another process for the preparation of has a boiling point relatively remote from that 50 50 antimony trichloride involves the reaction of of the antimony trichloride. Where it is desired antimony sulfide with chlorine gas. The anti to produce antimony penta, chloride, however, the mony sulfide is diluted with an inert material such chlorination of the metallic antimony is most as sand and the trichloride, after its formation, conveniently effected in a solvent such as nitro 55 55 is treated with additional antimony sulfide to re benzene which has a boiling point not far re 2 2,102,787 moved from that of the antimony trichloride. from metallic antimony to flavanthrone. As ex By distilling the crude antimony trichloride-sol amples of solvents which may be used in the for vent mixture, an antimony trichloride-solvent mation of the antimony trichloride may be men mixture is obtained which may be further chlo tioned benzene, toluene, solvent naphtha, carbon 5 rinated with very satisfactory results. The re tetrachloride, ortho-dichlorobenzene, nitroben 5 Sultant antimony pentachloride-containing mix Zene, Ortho-nitrochlorobenzene and para-nitro ture may then be reacted with beta-amino-an chlorobenzene. The nitrobenzene employed may thraquinone to produce flavanthrone in good be prepared by the nitration of benzene with ni yield. tric acid produced from metal nitrates such as The invention will be further illustrated, but is Sodium nitrate, or with synthetic nitric acid such () not limited, by the following example, in which as may be obtained by the oxidation of ammonia. the parts are by weight. It will be recognized that the results with all Sol EacGimple vents are not comparable. Benzene and ortho dichlorobenzene have given as good resultS aS Suspend 356 parts of finely ground metallic nitrobenzene in the formation of the antimony antimony in 1500 parts of nitrobenzene and, under trichloride. efficient agitation sufficient to keep the metallic In the formation of the antimony pentachlo antimony in suspension, introduce 258 parts of ride, it is desirable, although not essential, to en chlorine over the course of six to eight hours at a ploy a solvent which may also be used in the fla temperature of approximately 35° C. or lower. wanthrone condensation. For this purpose high- : The addition of chlorine may be regulated by the boiling solvents such as, for example, nitroben increase in weight or by an analysis to show the Zene, ortho-nitrochlorobenzene and para-nitro percentage of antimony trichloride in the nitro chlorobenzene may be mentioned. Nitrobenzene benzene solution. This should show the pres is especially desirable for use in the production of ence of 25% to 27% antimony trichloride. At antimony pentachloride and in the production of the end of the chlorination there should be ap flavanthrone, on account of the ease with which proximately 60 to 65 parts of unreacted antimony, the reactions proceed and the good yields ob Which amounts to approximately 18% excess of tained. In the formation of antimony penta metal. chloride-solvent mixtures and in the Subsequent Heat, the chlorination charge to 90° C. and hold condensation of such mixtures with beta-amino three hours so that any antimony penta, chloride anthraquinone, better results are obtained with Which is formed in Small amounts may be trans nitrobenzene than with Solvents Such as Ortho formed to trichloride by reacting with the excess nitrochlorobenzene and para-nitrochlorobenzene. of metal. This reaction may be shown to be The chlorination of the metallic antimony to complete when there is no increase in the forma antimony trichloride has been carried out with tion of trichloride as ShoWn by analysis. Remove very satisfactory results without the addition of the nitrobenzene-antimony trichloride mixture a catalyst. from the excess of antimony by decantation or The temperature employed in chlorinating the filtration, and distill either at atmospheric or re metallic antimony may vary within relatively 40 duced pressure, the distillation at reduced pres wide limits. A low chlorination temperature 40 sure being preferable. seems to give the best results, though chlorina Chlorinate the distilled nitrobenzene-antimony tions at a temperature as high as 85° C. have trichloride mixture by the introduction of chlo been made and give satisfactory results with the rine through a tube leading to the botton. Of the solvent, only slightly chlorinated. 45 vessel while maintaining the temperature at 15 In the formation of antimony trichloride, the 45 C. to 25° C. rate of chlorination may be increased over that To the resultant antimony penta, chloride-con given in the example but, in doing this, the taining mixture add beta-amino-anthraquinone amount of antimony pentachloride formed is in With continued agitation and condense to flavan creased. The excess of metallic antimony en throne by any suitable method. ployed in the antimony trichloride formation : In practising the invention, it has been found may be as low as 3% to 5%. This residual an that the presence of iron of antimony Sulfide does timony may be left in the chlorination vessel not injure the chlorination to the trichloride.