Патент USA US2135460код для вставки
Patented Nov. 1, 1938 i 2,135,460 0 UNITED STATES PATENT OFFICE ' 2,135,460v PREPARATION OF BORON FLUORIDE Donald J. Loder,‘ Wilmington, Del., assignor to E. I. du Pont de Nemours & Company, Wil mington, Del., a corporation of Delaware No Drawing. Application August 5, 1936, Serial No. 94,337 8 Claims. (01. 23-88) This invention relates to- a process for the After the removal of the water by distillation or ' preparation of boron-halogen compounds and other means there remains the metal halide _more particularly to the preparation of boron boron-halogen complex. If the metal halide em ?uoride. 5 _ ‘ ployed is an alkaline earth halide or an alkaline - An object of thepresent invention is to provide ,earth salt or oxide, such, for example, as calcium 5 a process for the separation of constituents from complexes containing the same and more partic ularly to the separation of boron ?uoride from its complex. Another object of the invention is 10 to provide a process wherein a boron-halogen - containing compound is separated from its com plex with water. A further object of the inven tion is to provide a process wherein an alkaline earth metal halide is added to a complex, com - 15 pound, mixture, or solution of water and- boron I carbonate, calcium oxide and the like which re act with a boron halide to form an alkaline earth halide, the boron-halogen constituent can be ob tained in a substantially anhydrous ~form by simply heating the complex to a temperature of 10 from 150 to 300° C. , The metal halides ‘which have been found par- , ticularly well adapted for replacing water from complexes containing them and a boron-‘halogen containing compound include, for example, cal- 15 ?uoride; the water is removed and the boron lcium'?uoride, zinc ?uoride, aluminum ?uoride, ?uoride recovered in the anhydrous form. A aluminum chloride, cuprous chloride, lead chlo more speci?c object of the invention is to provide rlde, iron chloride, tin chloride, calcium chloride, a process wherein complexes containing boron ‘barium chloride, and analogous metal ?uorides, 20~ ?uoride, and water may be so treated that the chlorides, bromides, and iodides. While metal 20 anhydrous boron ?uoride is freed from the water. halides will replace the water in a complex con Other objects and advantages of the invention taining it and a boron-halogen constituent, such will hereinafter appear. _ I have found that if a boron-halogen-water as boron tri?uoride', I have found in addition that the alkaline earth halides and more especially the alkaline earth ?uorides form a complex or 25 25 complex, compound, mixture, or solution is treated with a metal halide the water will be set - compound with boron ?uoride from which the free, leaving a compound formed between the boron ?uoride or other analogous, easily volatil metal halide and the boron-halogen constituent. ized, halogen-containing compound may be re Moreover, if alkaline earth metal halides are covered by heating. The alkaline earth halides, 80 employed, the alkaline earth metal halide-boron such, for example, as the ?uorides, chlorides, and 30 halide reaction product will, upon heating, give bromides of calcium, barium or strontium, and up the boron halide it contains leaving the alka salts thereof which react with boron halides to line earth halide as a residue. Accordingly when form alkaline earth halides likewise have the employing alkaline earth ~metal halides it is ability to not only displace the water from its 36 possible to recover the boron-halogen-contain complex with a. boron halide, but also to permit 35 ing constituent from water. > the recovery of the boron halide from the alka Boron ?uoride, and analogous boron-halogen line earth halide. ‘The advantages of my process for the prepara compounds, form with water and other com pounds an association that has been generally tion of anhydrous volatile halides from complexes 40 called in the literature a “complex.” In this containing them' can I be readily appreciated. 40 " speci?cation and the claims appended thereto. For example, hydrated boron ?uoride can be this association will be referred to as a “complex” prepared by interacting anhydrous hydro?uoric altho this term will be understood to‘ include acid with solid orthoboric. acid, boric anhydrides ‘ water and a boron halogen compound whether 45 they‘rare present as a solution, mixture, com pound, or complex, or whatever maybe the man ner of their association. ' Generally, my‘ process is effected in the follow ing manner; a metal halide is added to the com 50 plex containing water and a boron-halogen con stituent and apparently due to the fact that the boron-halogen constituent reacts more readily with the metal halide, a complex is preferentially formed between the metal halide and the boron 55 halogen constituent, thereby freeing the water. or borates. The reaction may be effected by the addition of the anhydrous hydrogen ?uoride to 45 ' the solid orthoboric acid, boric anhydride or borate which comprises essentially a vhydrated boron tri?uoride. To this product calcium ?u oride is added, water is liberated and can be re moved by a simple heating operation to a tem- 50 perature of about 110° C. thereby leaving as a residue a'compound. containing calcium ?uoride and boron ?uoride. By heating this substan tially anhydrous material to a higher tempera- . ture, say form 170 to 500° 0., usually a tempera- 55 . ture of 250° C. is sumcient for satisfactory‘ recov -.ery, the boron ?uoride can be driven off in a sub stantially anhydrous form leaving calcium ?uo ride as the residue. I shall now illustrate by way of examples meth ods of preparing boron ?uoride from various com plexes containing it but it will be distinctly under stood that the invention will not be limited spe 10 ci?cally to the details of the examples. Example 1.—-121.8 grams of (HzO)a.BF: (1 mol) is treated with 45 grams CaF: (.58 mol) in a ?ask‘ attached to a short fractionation column. The mixture is heated in an oil bath to not more than 150° C. at one atmosphere pressure, during 15 which the water and a small amount of boron ?uoride is distilled out. The distillation can be effected at atmospheric or reduced pressures. densing agent can be recovered and used over and over again the sole loss in catalyst occurring from usual physical operating causes rather than from loss due to by-.product formation. From a consideration of the above speci?cation it will be appreciated that many changes may be made in the process herein described without departing from the scope of the invention or sac ri?cing any of the advantages that may be de rived therefrom. . I claim: _ 1. In a process for the preparation of boron ?uoride and steps which comprise reacting a metal halide with a water-boron ?uoride complex and subsequently separating from the resulting 15 metal halide-boron ?uoride complex the boron ?uoride.. . . - 2. A process for the preparation of boron ?uo consists mainly of Ca(BF4) 2, totemperatulres be- I ride which comprises reacting a compound se lected from the group consisting of an alkaline tween 300° C., and 500° 0., resulted in the evo lution of boron ?uoride according to the equa earth halide and an alkaline earth salt that will Subsequent heating of the solid residue, which 25 tion: Ca(BF4)z—>CaFz+2BF3. Temperatures be form a halide when reacted with a boron halogen low and above those given may be used but the compound with a water-boron ?uoride complex range given is preferred. and subsequently removing from the resulting Example 2.—-51.9 grams of (H20) z.BF':'(.5 mol) is treated with 25 grams NaF (.6 mol) in a. ?ask complex the boron ?uoride in a substantially 25 attached to a short fractionation column. The . mixture is heated in an oil bath to approxi mately 150° 0., during which time water is The distillation can'be conducted at 30 evolved. atmospheric or reduced pressures. The BF: can be recovered by heating the solid, which con sists mainly of NaBFi, to higher temperatures. 7 anhydrous form. ' 3. A process for the preparation of a boron ?uoride which comprises reacting a boron ?uoride associated with water with calcium ?uoride, heat ing and evaporating the water from the result ing mixture, and subsequently, at a higher tem perature driving off the boron ?uoride. 4. A process for the preparation of boron ?uo- ' . Example 3.—About 60.9 grams (H2O) 3.]3Fa (.5 mol) was treated with 60 grams NaCl (1 mol) in a ?ask attached to a short fractionating column. The mixture was heated in an oil bath to not ride which comprises reacting a complex of water and boron ?uoride with calcium ?uoride, heating 35 and evaporating the water from the resulting solid residue (NaCLBFa) by further heating to ing and removing all the water, and subsequently, mixture, and subsequently, at' a higher tempera- ‘ more than 150° C., to drive off the water. The‘ ture driving off the boron ?uoride. distillation can be carried out at atmospheric or 5. A process for the’ preparation of boron tri-. 40 reduced pressures. . ?uoride which comprises reacting a water-boron The boron ?uoride can be separated from the tri?uoride complex with calcium ?uoride, heat from 300-500" C. - If desired the condensate obtained by heating 45 the mixture containing the water, boron ?uoride, and a metal halide can be distilled to give a resi at a higher temperature, driving oil the boron tri?uoride. . 6. A process for the preparation of boron tri ?uoride which comprises reacting a mixture con due containing substantially all of the boron' taining one'mol of a boron tri?uoride water com ?uoride originally present in the condensate. This residue may be combined with the next 50 batch of water-boron ?uoride to be treated there plex with approximately one-half mol of calcium ?uoride, heating and removing the water and subsequently, at a higher temperature, driving by providing a method of substantially complete ' 01! the boron tri?uoride. recovery of the‘boron ?uoride.. 7. In a process for the preparationvoi' a boron ?uoride the steps which comprise reacting a com My' process is particularly vwell adapted for use in separation of a boron-halogen constituent 55 from addition compounds containing it and water and more particularly such addition compounds in which the halogen constituent is a highly vola tile halide, such, for example, as‘ the ?uorides, chlorides,-bromides, and iodides of boron. Cal 60 cium ?uoride is particulary well adapted for use in a process for separating not only- the water from a water-boron ?uoride complex, but to separate the calcium ?uoride-boron ?uoride complex-formed into boron ?uoride and calcium 65 ?uoride. It will be appreciated that when em ploying boron ?uoride as a condensing agent in organic acid reactions the use of calcium ?uoride is particularly useful for the reason that the con ' ' pound selected from the group consisting of anv alkaline earth metal ?uoride and an alkaline 55 compound that will form a ?uoride when reacted with a boron ?uoride, with a water-boron ?uoride complex andsubsequently separating from the resulting metal halide-boron ?uoride complex the 60 boron ?uoride. 8. In a process for. the preparation of a boron ?uoride compound the steps which comprise add- ‘ ing an alkaline earth metal halide to a. water-' boron ?uoride complex and subsequently sepa rating from the resulting alkaline earth metal halide-boron ?uoride complex the boron ?uoride by heat. DONALD J. LODER. ‘CERTIFICATE OF dbRREcTIoN. Patent No° 2,l55,h60, ' ' " November- 1, 1958., DONALD J. LODER. 'Itis hereby certified that error appears in the printed specification of the above numbered patent requiring’ correction he follows: Page 2,7 second ‘ column, line '15, claim 1, for the word "and" read the; and that the said Lettere Patent shouldbe read-with this correction therein that the same may conform to the record of the case in the Patent Office“ ‘Signed and sealed this 20th day of December,7 A. D. 19580 ‘Henry Van Aredal‘e (Seal) Acting Commissioner of Patents.