Alginic acid methyl ester sulfates, preparation and molecular weight fractionation thereof

Claim 1

THE METHOD OF PREPARING A FRACTION OF SULFATED ALGINIC ACID METHYL ESTER FREED OF RELATIVELY HIGH AND RELATIVELY LOW MOLECULAR WEIGHT CONSISUENTS WHICH COMPRISES: PREPARING THE METHYL ESTER OF ALGINIC ACID BY DIGESTING ALGINIC ACID IN METHANOL IN THE PRESENCE OF AN ACID ESTERIFICATION CATALYST, FILTERING OFF THE RESULTING INSOLUBLE METHYL ESTER, WASHING THE ESTER FIRST WITH METHANOL AND THEN WITH ACETONE, AND DRYING THE WASHED ESTER, DIGESTING THE RESULTING ESTER IN THE PRESENCE OF AN ACID ACCEPTOR WITH CHLOROSULFONIC ACID AT A TEMPERATURE OF ABOUT 77*C. FOR A PERIOD OF FROM ABOUT 0.5 TO ABOUT 2 HOURS, DILUTING THE REACTION MIXTURE WITH WATER AT THE MELTING POINT OF ICE, ADDING THE RESULTING AQUEOUS SOLUTION TO A MULTIPE VOLUME OF ETHANOL, SEPARATING THE RESULTING PRECIPITATE, WASHING IT IN TURN WITH ETHANOL AND ACETONE, AND DRYING IT, DISSOLVING THE DRIED MATERIAL IN 12 TIMES ITS WEIGHT OF 50% AQUEOUS ACETONE, ADJUSTING THE SOLUTION OF A PH OF 7.5 BY ADDING A BASIC SODIUM COMPOUND PRECIPITATING THE RESULTING SODIUM SALT OF SULFATED ALGINIC ACID METHYL ESTER BY ADDING TO THE SOLUTION A MULTIPLE VOLUME OF ANHYDROUS ACETONE, WHEREBY A FRACTION OF SULFATED ALGINIC ACID METHYL ESTER HAVING AN AVERAGE MOLECULAR WEIGHT IN THE APPROXIMATE RANGE 7200-8000 IS OBTAINED IN THE FORM OF A SODIUM SALT.