Color stabilizing process for the manufacture of ester-type anionic surface active agents

Claim 1

IN THE PROCESS OF PREPARING ESTER-TYPE ANIONIC SURFACE ACTIVE AGENTS BY THE CONDENSATION REACTION OF A MONOCARBOXYLIC ACID OF FROM 8 TO 22 CARBON ATOMS WITH A SALT SELECTED FROM THE GROUP OF ALKALI METAL AND ALKALINE EARTH METALS OF A B-ALKYLISETHIONATE, WHEREIN THE ALKYL IS OF 1 TO 4 CARBON ATOOS, AT A PH OF ABOUT 2.5 TO 3.5 AND A TEMPERATURE OF 140 TO 320* C. IN THE PRESENCE OF A CATALYTIC AMOUNT OF A COMPOUND SELECTED FROM THE GROUP CONSISTING OF HYPOPHOSPHOROUS ACID AND ITS METAL, AMMONIUM AND AMINE SALTS, THE IMPROVEMENT OF OBTAINING THE SAID SURFACE ACTIVE AGENTS SUBSTANTIALLY COLOR FREE WHICH COMPRISES INTERDUCING AT A STAGE OF SAID REACTION CONSISTING OF PRIOR TO THE ONSET OF THE SAID REACTION AND DURING THE SAID REACTION FROM 0.01 TO 10% OF AN INORGANIC COMPOUND SELECTED FROM THE GROUP CONSISTING OF HALIDES, NITRATES, SULFATES, PHOSPHATES, CARBONATES, OXALATES AND CITRATES OF METALS SELECTED FROM THE CLASS CONSISTING OF POTASSIUM LITHIUM, CESIUM, RUBIDIUM, BERYLIUM, BARIUM, CALCIUM, MAGNESIUM, CADMIUM AND TRONTIUM.