Patent GB-1074243-A (GB)
Title: Ammonium polyphosphates and compositions containing the same
IPC: D06M11/00
Filed: 1964-08-13
Abstract: Substantially water insoluble ammonium polyphosphates are prepared by heat treatment of any of (a) urea phosphate (e) the reaction product of a condensed phosphoric acid and a combined ammoniating and condensing agent (c) the reaction product, with a combined ammoniating and condensing agent, of an ammonium phosphate with a combined ammoniating and condensing agent (d) ammonium pyrophosphate with a combined ammoniating and condensing agent (e) ammonium orthophosphate with a combined ammoniating and condensing agent.  The compounds are of general formula HxNmPnOy where n is an integer with an average value of from 20 to 400, m/n is from 0.7 to 1.1, x has value from (n + 3m) to (n + 2.Fm) and y has value from (2.8n to 3n + 1) and, more particularly with general formula Hn-m(NH4)mPnO3n+1, wherein n is an integer having average value from 20 to 400 and m/n is between 0.7 and 1.1.  The polymers may have either straight or branched chain structures but the chains may not come together to foam rings.  The heat treatment is preferably under substantially anhydrous conditions. The condensed phosphoric acid may contain 72-85% of P2O5 by weight.  The combined ammoniating and condensing agents are those nitrogeneous compounds capable of releasing ammoniacal nitrogen and condensing with the phosphorus-containing reactant or reactants between 170 DEG  and 260 DEG  C.  Examples are amides with one or more amide groups containing carbon and nitrogen and one or more of sulphur, oxygen and hydrogen as well as no carbon-carbon double bonds and especially compounds with a molecular weight of less than 200 containing one or two radicals chosen from carbamyl, sulphamino, sulphamyl and ureido. Such compounds are urea, ammonium carbamate, biuret, sulphamide, sulphamic acid, ammonium sulphamate, guanyl urea, methyl urea, amino urea, 1,3-di-amino urea and biurea. The heat treatment is conducted at from 170 DEG  to 260 DEG  C. for times from 5 minutes to 4 hours, e.g. between 210 DEG  to 240 DEG  C. for 1/2 -1\ba1/2 hours. Examples of the reactions are firstly, the reaction product of (b) above, may be obtained by mixing the phosphoric acid and combined ammoniating and condensing agent and heating if necessary.  The reaction is usually exothermic at 120 DEG to 150 DEG  C., but heating at 110 DEG  C. externally for 1-6 hours may be used.  The N/P molar ratio of reagents may be from 1 to 5. A further method is the reaction of orthophosphoric (40-85% by weight) with the combined ammoniating and condensing agent with N/P molar ratio of from 0.7 to 5.  The reaction usually occurs at 110 DEG  to 140 DEG  C. for 1-3 hours. With N/P ratio of 1.4-1.75 a novel ammonium pyrophosphate of empirical formulaNH2.7H1.3\t P2O7 is the product.  When the N/P ratio is 2.5-4.0 the product is a novel ammonium pyrophosphate of formula NH3.3H0.7P2O7.  Both of the novel pyrophosphates have distinctive X-ray patterns.  The products are then treated with a combined ammoniating and condensing agent at 170 DEG  to 260 DEG  C. for 15 minutes, to 3 hours to produce the polyphosphates.  The N (from combined ammoniating and condensing agent) to P (from the pyrophosphate) ratio is from 1 to 7.-The polyphosphates have use as fire-retardants in plastics, textiles and paint compositions, as builders in synthetic detergent compositions or as fertilizers.  The novel pyrophosphates are useful as buildings in synthetic detergents and as fertilizers.