Process for the modification of polysaccharides

Claim 1

A PROCESS FOR THE PREPARATION OF PHOSPHORUS AND NITROGEN CONTAINING CHEMICAL DERIVATIVE OF POLYSACCHARIDES, WHICH COMPRISES DEHYDRATING A PULVERULENT MASS OF A HIGH MOLECULAR POLYSACCHARIDE BY HEATING SAID MASS UNDER VACUUM UNTIL THE MASS CONTAINS SO LITTLE MOISTURE THAT NO PASTING WILL OCCUR IN IT IN THE ENSUING TREATMENT; THEN WHILE EXCLUDING OXYGEN FROM THE DEHYDRATED MASS HEATING IT FURTHER IN THE PRESENCE OF A PHOSPHORUS COMPOUND CONDENSABLE WITH SAID POLYSACCHARIDE AND BEING SELECTED FROM THE GROUP CONSISTING OF PRIMARY, SECONDARY AND TERITARY OTHEROPHOSPHATES, PYROPHOSPHATES, HYPOPHOSPHATES, METAPHOSPHATES, POLYMETAPHOSPHATES, ORTHO-, PYRO- AND METAPHOSPHORIC ACIDS AND MIXTURES THEREOF, AND ALSO IN THE PRESENCE OF A NITROGEN COMPOUND CONDENSABLE WITH SAID POLYSACCHARIDE AND BEING SELECTED FROM THE GROUP CONSISTING OF UREA, THIOUREA, MONO- AND POLYMETHYLOL UREAS, FORMAMIDE, TRIMETHYLAMINE, TRIETHANOLAMINE, HEXAMETHYLENE TETRAMINE, ALKALINE REACTING INORGANIC AMMONIUM COMPOUNDS, AND MIXTURES THEREOF, TO A TEMPERATURE SUFFICIENT TO EFFECT CONDENSATION OF SAID PHOSPHORUS AND NITROGEN COMPOUNDS WITH SAID POLYSACCHARIDE; AND THEREAFTER COOLING THE REACTION MASS WHILE STILL EXCLUDING OXYGEN FROM IT, TO RECOVER THE CONDENSATION PRODUCT IN A FINELY DIVIDED FORM.