Patented July 21, 1953 2,646,344 Jonas Kamlet, Easton, Conn, assignor to Amer ican Potash & Chemical Corporation, Trona, Calif., a corporation of Delaware No Drawing. Application September 27, 1952, serial No. 311,943 s. 1. Claim. (C1.23-203) 1 : 2 : . This invention relates to a process for the with ammonia in the Vapor phase to form adipo manufacture of boron phosphate (BPO4). More dinitrile for the nylon process (Arnold and partietary, it relates to a simple process where Iazier-U.S. Patent : 2,200,734); . by-boron phosphate:may be manufactured in a (e). As a catalyst in the dehydration of ethyl single step from cheap and readily available raw senic and cycloaliphatic alcohols (Usines. de . Melle-British Patent. 589,709); materials.Boron phosphate has heretofore been s manu (f) As a catalyst in the vapor phase methyl factured by the following methods: . ation of benzene with dimethyl ether to form (a) By the reaction of boric anhydride with toluene . (Given and Hammick, Journ. Chem. phosphorus oxychloride or phosphorus penta () Soc. 1947,928-935); chloride, according to the equations: (g) As a catalyst in the vapor phase nitration of aromatic hydrocarbons in petroleum with NO2 (Rout, U. S. Patent 2,431,585); (h) As a catalyst in the desulfurization of at 150°-170° C. for 8-10 hours, or by the reaction hydrocarbons in petroleum refining (Krug, U. S. of phosphorus pentoxide with boron trichloride Patent 2,441,493); at 200° C. for 2-3 days (Gustavson, Berichte 3, (i) As a catalyst in the dehydration of hy 426 (1871), Zeit. Chem. (2) 7,417 (1871); von droxylated oils, such as castor oil, for the manu Richter, Berichte 4,976 (1872); . s facture of drying compositions (Rust, U. S. Pat (b) By the reaction of boric acid with phos ent 2,456,996); phoric acid, followed by a calcination to dehy (i) As a component of coating baths for use drate the resultant borophosphoric acid (Vogel, in the phosphatizing of ferrous metal surfaces Zeit. Chem. (2) 6, 125 (1870); Meyer, Berichte (Gilbert-U.S. Patent 2,479,564). 22, 2919 (1889); Levi & Ghiron, Atti Accad. Lincei, I have found that boron phosphate can be 18, 394-8 (1933); or . 2 5 made simply and in good yield by adding phos (c) By the reaction of boron trichloride with phorus pentoxide to molten boric anhydride. red phosphorus and air at advanced tempera Boric anhydride (boron oxide-B2O3) melts at tures (Krol. 1, Zeit. anorg. allgemein. Chemie, 577 C. to a clear liquid. The addition of phos 102, -33 (1918); Journ. Chem. Soc. 114II, 109). phorus pentoxide, in small portions, to an agi Boron phosphate is a white solid, melting tated melt of boric anhydride, at a temperature above 1250° C., density -2.532, insoluble in hot between 577 C. and about 1000° C., causes an and cold water and in all common organic sol exothermic reaction to occur, with the forma vents and not attacked by acids. Hot caustic tion of boron phosphate, according to the equa alkali solutions or molten alkalies will slowly dis tion: Solve boron phosphate (Prescher, Acad. Pharm., 35 242, 194 (1904). The phosphorus pentoxide of commerce sub These properties and the high degree of chem limes at 210°-250° C., the sublimate forming a ical stability make boron phosphate suitable for vitreous modification which does not melt till a use in ceramic manufacture, earthenware fabri red heat is attained. Thus, it is highly desirable . cation, for acid-resistant coatings and cements, 40 to effect this reaction under conditions which enamelling compositions, protective coatings, as Will minimize losses of phosphorus pentoxide by pigment in high-temperature paints, etc. Boron Sublimation. The reaction may be effected in phosphate has also found utility in the following Closed vessels, under atmospheric or superatmos fields: --- pheric pressures. The phosphorus pentoxide may (a) As a catalyst in the reaction of ethylene, 45 be added below the surface of the molten boric carbon monoxide and steam to form propionic anhydride, or to a well agitated melt of boric acid (Vail, U. S. Patent 1,924,764); anhydride, in such a manner as to obtain most (b) As a catalyst in the hydration of acetyl rapid and intimate contact between the reagents. ene to acetaldehyde with steam (Horsley and The Sublimed material collecting on the upper Imperial Chemical Industries, British Patent 50 Surfaces of the reaction vessel may be periodi 351,016); cally removed and returned to the melt. (c) For improving the octane rating of motor This process may be effected in any suitable fuels (N. V. de Bataafsche Petroleum Maat., acid-resistant vessel with heating elements or British Patent 446,621) ; direct. gas or oil firing. As the phosphorus pent (d) As a catalyst in the reaction of adipic acid 55 oxide reacts with the boric anhydride, the clear 2,646,844 3 4. melt becomes more viscous. When equimolecular parts of phosphorus pentoxide. This corresponds proportions of the reagents have been mixed, to one mole each of B2O3 and P2O5. When the the melt Will set to a Solid White maSS of boron reaction is completed, the melt is removed from phosphate, which may then be cooled, Com the reactor and is allowed to solidify and cool in minuted and ground to any desired fineneSS. The pans. The solidified melt is then fragmented yield of boron phosphate is usually over 95% of mechanically and ground to a White powder of the theoretical. 60-100 mesh fineness, suitable for most catalyst Since this reaction is effected with molten uses and in the manufacture of ceramic com boric anhydride, the lower limit of the reaction positions. For use as a pigment and in protec temperature is the melting point of boric anhy 10 tive coatings, the BPO4 should be ground to about dride, i. e. 577 C. The upper limit of the reac 200 mesh. There is thus obtained a yield of tion temperature is about 1000 C., since losses 205 parts of boron phosphate, equivalent to about of phosphorus pentoxide by Sublimation become 96.6% of theory. marked above that temperature. What I claim and desire to protect by Letters The following example is given to define and 5 Patent is: to illustrate this invention, but in no way to limit A process for the manufacture of boron phos it to the reagents, proportions or conditions de phate which comprises reacting equimolecular Scribed therein. Obvious modifications will oc proportions of boric anhydride and phosphorus cur to any person skilled in the art. All propor pentoxide at a temperature between 577 C. and tions given are in parts by weight. 20 1000° C. Eacctimple JONAS KAMLET. In a Suitable, Stainless Steel, direct-fired reac References Cited in the file of this patent tor, melt 70 parts of boric anhydride and heat to Mellor: “Comprehensive Treatise on Inorganic a temperature of 600-650° C. Add now, with and Theoretical Chemistry, vol. 5, page 147 good agitation, in Small portions, a total of 142 (1924). .