Patented May 8, 1945 2,375,638 UNITED STATES PATENT OFFICE 368). OSPORCAC) AND METHOD OF PSEPARNG SE SAE Leonard H. Egguani, Winona, illinn. No Drawing. App3.cation May 17, 1942, Seria Ne, 393,938 6 Claims. (C. 23-166) This invention relates to the provision and pro phosphorus pentoxide P2O5, to about four molec diction of phosphorus pentoxide derivatives and ular equivalents of the boric acid B(OH) are has as a general object the provision and prepa employed in the reaction which is represented by ration of a novel boro-phosphoric acid and a the following equation: . method of preparing various salts thereof. A more specific object of the invention is the provision of a novel powdery non-hygroscopic While do not wish the invention imited to acid comprising acid oxide groups of boron and any theory of the reactions which may be in phosphorus together with certain molecular pro voived, in view of the generai belief stated above, portions of water. C it Enight toe we to point out by way of possible Another object of the invention is the pro explanation that i believe the two molecular vision of a novel boro-phosphoric acid which has equivalents of the phosphorus pentoxide, 2Paos, a relatively great capacity for neutralizing bases abstract from the four noiecular equivalents of and which can be readily stored and handled as the horic acid, 43(OH)3, three Eholecular equiva other non-corrosive powders without requiring lents of Water. Tiki as the boron oxide groups experasive subber-coated or rubber-lined equip ray be C33 'feite it one notects r equivalent ment and containers. . . . . of pyro-bogic &cidi, E653C5, &nd one inolecular A further object of the invention is to pro equivalest of Rheia riotic acid, Sai:04 according vide such 33 acid as a solice of certain. Seiful to tie folio Yigg eqL3 ion: derivatives including borCE phosphate, animo Kaira salts of the acid, and Sodius Saits thereof 2 (1). 45(OH)3–522aos--Essaos--3Eto as yell as the saits of other 8.2kaline earth inetas. Ugier Ethe conditions of the reactions to be The invention has as another object, the pro more fully described presently, the pyro- and vision of a novel and improved nethod of pre reta-3Eisc 2:ids procally contiine to form one paring tile novel acid a2 its saits and other molecular equivalent of tetra-boric acid, EabO, derivatives involving 2, reaction betweeg hos 25 with the EiEGr8%ion of two EYolecular equivalients phots petoxide aafi Oric acid. of w8ter Vykhic g.ge frea to evapogate. is reac Other objects of the invention will become ap tion. E18 y 8 Represelled by the ÉcEowing equa parent, fron the following description of a pre tiQ: feed erodiest of the iWeisi. . . . It is generally elieved that city Cowdered 202ic (2) *E4E205--fig6204-Fig.5:0+2E20 acid does act, react. With dry goveege6 acs The tWe Estelects eggivalerts of the phos phorus peel toxide, and fielzer tist if Wate; e. phic;ts 2832.É05:ce, 2,305, wi&f the tee rosecular added to the Yixture of such powers, one of equivalients of water (see Equistics 1 above) the fooying restats wi: ; be fined: abst:ected frozzi. the four molecular eggivalients (a). Rae ionization of a groportioai E. E.I.O.R., of 35 of the figgic acid, 45 (CEE)3, a slieve, for in one meta-pinosphoric acis, 3EOs, with boric acid, molecikai scaivai.eXe of tetre-gkacsitoric acid, B(OE)3 according to the equatic E. Eigraois, according $2 the equationa: (3) 2F2C3-33:C-EPass (b) If more water be added, the formation of 4. That tetra-hCSpiezis acid, EoPaois, probably a larger proportion of either of both of the phos consibilies with the et's-Si-Cric acid, HaBadi to phoic acids, Raetas, iiO3, 2nd (the E304 foSEE GE:e EaCe3222 equivalet of the ovel acid with goric acid or with hostic Eide, EaC3, accordi herefE called tetraitsgokypergiosphoric acid, ing to the following respective equations: 3463? (): Eaga, i.e.8%ine g (2.3 Eriecular equiva 45 leFit Cf W&g Vyhich is free to evapagate agdi which is 22°Cibaki Soigned by the seggaging off of two hydrogei &te as '05, the G&E alepolic acid and one oxyger atom feat the teta-phosghoric acid Notwithstanding that general belief, I have dis 5. reit.giF?g the atter to the agaiphosphoric acid, covered a powdery roa-hygroscopic acid co lowingis?03. eq&tioR:Stach reaction is represented by the foll prising poly-2.Écil oxide grguags of boro, and pinese phots together vira. Certain Yasiecies regi (4) EEAO--Earas-Boca (Exiaosa-i-Hao tions of water, and R37 to zinake stack an acid 55 Regardless of the correct S3Eightion, when in and derivaiyes thereof by reacting, cominereig &ccordia2.ce with SSS is ve2 in the connereial dry powdered Giric acid with coastercial dry de: OW ciel's Of 262sgous feistoxide and ioric powdered phosphorus pentoxide. The novel acid acid are is tigiately Eicked in the proportions has the for a la, B4C7 (H3POs) 22, therefore R&S hereifiabove described a di to that mixture is been terrned tetraborohypophosphoric acid. added a small quantity of water, a reaction is Approximately two molecular equivalents of the 60 almost immediately initiated and proceeds

ts 2 2,875,638 throughout the entire mixture with a hissing at the ebullition point. The product made by noise and the evolution of fumes and results in heating below the ebullition point differs from a generous yield of the novel boro-phosphoric. the other in that it is very slowly soluble, even in acid. hot water, whereas when prepared by heating at For example, 56 grams of commercial powdered the ebullition point, the resulting Salt is so in phosphorus pentoxide are intimately mixed with stantly soluble in water that the escape of Oc 50 grams of commercial powdered boric acid. cluded air is audible when a lump of it is dropped After so mixing, one or two drops of water are into water. added to the mixed powders whereupon the vigor Sodium salts of the novel acid have thus been ous progressive reaction occurs as just described. O prepared ranging from those having a sharp acid The resulting mass is slightly moist and Weighs reaction to those which are alkaline in solution. a little less than the total Weight of the con Such salts which are alkaline have valuable de ponents. After drying in a hot air Owen, at a tergent, emulsification, and water conditioning temperature less than 100 degrees C., the yield is properties and may be incorporated in water sol 95 grams of the tetraborohypophosphoric acid. 5 uble soaps. Those which are acid exhibit a de The novel acid so made is a dry non-hygro gree of tackiness or adhesiveness that is truly Spopic powder and hence can be handled and remarkable. In addition the sodium salts are stored as any non-corrosive powder without em useful in coating filters used in air conditioning ploying expensive rubber-lined equipment and apparatus by immersing the filters in water Solu containers. In general it has the properties of 20 tions of the salts and thereafter evaporating the Ortho-phosphoric acid and in addition it has excess water. other properties not possessed by ortho-phos Similarly, the products of this reaction between phoric acid. It has a relatively great capacity to boric acid and mono-ammonium phosphate, di neutralize bases. For example, 17% grams of ammonium phosphate, or mixtures of sodium and SOdium carbonate was required to be added to 10 25 ammonium phosphates are made and the resulting grams of the novel acid to develop an alkaline re salts exhibit either an acid or alkaline reaction action with phenolphthalein. in accordance with the ratio of the bases and The novel acid has many desirable derivatives. acid oxide groups which may be present. Such One such derivative is boron phosphate. BPO4. salts have a syrupy consistency which persists Boron phosphate has valuable applications as a 3 even after baking at high temperatures. The re catalyst in organic reactions and especially in sistance to crystallization under such conditions thermal treatments of petroleum derivatives and makes these salts useful as the dispersion agent as a double acid oxide component of vitreous in fire-proofing or fire-resisting compounds. enamels and ceramic products. It is made ac While a specific embodiment of the invention cording to the invention by heating, for example, 85 has been described, it will be understood that 10 grams of the novel acid for one-half hour at the invention is not limited to the precise de red heat with a yield of 8.9 grams of boron phos tails hereinabove set forth by way of illustra phate. The reaction is tion, but instead what is claimed and desired to be secured by United States Letters Patent is: B401 (H3POs) a-24BPO4--3H2O. 1. The method of producing a water soluble The water soluble form of boron phosphate is phosphorus-boron containing composition which made when the temperature employed in the re comprises reacting boric acid with phosphorus action just described is less than 400 degrees C. pentoxide at a temperature below 400 C. in the but not less than about 200 degrees C. So made, presence of a reaction product of water and phos the resulting boron phosphate slowly hydrolyzes 4. 5 phorus-pentoxide. and dissolves in water. The water and acid in 2. The method of producing a water soluble Soluble form of boron phosphate is made by em phosphorus-boron containing composition which ploying in the above mentioned reaction a tem comprises reacting boric acid with phosphorus perature above 400 degrees C. The resulting pentoxide at a temperature below 200 C. in the boron phosphate is not only water insoluble but 5 0 presence of a reaction product of water and phos phorus pentoxide. - is also infusible at whiteheat. 3. The method of producing a water Soluble The ammonium, sodium, and other alkaline acid anhydride having the empirical formula sey: salts of the novel acid are made in general BPO4 which comprises heating at a temperature (a) Neutralizing or combining such bases with. 5 of between 200° C. and 400° C., a compound ob the novel acid in aqueous solution; or tained by reacting boric acid with phosphorus. (b) Combining the alkaline-base with boric pentoxide at a temperature below 200 C. acid and, with the borate thus obtained, reacting 4. A compound selected from the group consist phosphorus pentoxide in the manner described ing of a water soluble compound obtained by re hereinabove for the preparation of the borophos- 80 acting boric acid with phosphorus pentoxide at phoric acid; or a temperature below 200°C., and salts thereof. (c) In some cases mixing and heating the al 5. A water soluble composition having the em. kaline base, boric acid, and phosphoruspentoxide pirical formula HoPB4O19 obtained by reacting withoutfirst making the borate. boric acid with phosphorus pentoxide at a ten For example, crystalline disodium phosphate is 6 perature below 200 C. heated until it melts or dissolves in its water of 6. A water soluble acid anhydride having the crystallization, Boric acid is then dissolved there empirical formula BPO4 obtained by heating at a in. The Solution so prepared does not recrystal temperature between 200° C. and 400° C., a water lize upon cooling but remains as a syrupy liquid. soluble compound obtained by reacting boric acid If that solution be heated to a temperature below with phosphorus pentoxide at a temperature be-, the ebullition point, a different salt is obtained 7 low 200° C. from that obtained where the temperature is kept LEONARD H. ENGLUND.