METHOD FOR OBTAINING MELAMINE POLYPHOSPHATE Russian patent published in 2021 - IPC C07D251/54 C07D251/70 C09K21/12 

FIELD: organic synthesis.

SUBSTANCE: invention relates to synthetic organic chemistry, namely to a method for producing melamine polyphosphate. The method is carried out in a two-bladed mixer for mixing viscous media and includes loading phosphoric acid, which is heated from 180 to 230°C, creating a vacuum from 0.93 to 0.7 bar with a pump, stirred for 30-60 minutes, followed by the addition of melamine to the resulting melt at 280°C while stirring for 30-60 minutes and at 300°C with holding the mixture for 60 minutes. With the last portion of melamine, ammonium oxalate is added to maintain the pH of the product medium more than 5. The molar ratio of melamine to phosphoric acid and ammonium oxalate is 1:0.5-2:0.08-0.24.

EFFECT: invention makes it possible to obtain melamine polyphosphate with high thermal stability, a residual mass after decomposition of at least 80%, a pH of 10% suspension of more than 5, using a single apparatus, without isolation of intermediate and final reaction products, without a solvent, as well as high water and energy consumption.

1 cl, 1 dwg, 1 ex