Process for the continuous manufacture, purification, and isolation of lactic acid

Claim 1

A PROCESS FOR THE CONTINUOUS MANUFACTURE, PURIFICATION AND ISOLATION OF LACTIC ACID, WHICH COMPRISES HYDROLYZING LACTIC ACID NITRILE WITH AT LEAST THE MOLAR AMOUNT OF A 50 TO 70% SULFURIC ACID AT A TEMPERATURE WITHIN THE RANGE OF ABOUT 120 TO 130* C. AND WITHIN 2 TO 4 HOURS WITH THE RESULTING FORMATION OF LACTIC ACID; EXTRACTING THE RESULTING AND COOLED REACTION MIXTURE AND THEREBY SEPARATING ORGANIC CONSITUENTS FROM AMMONIUM BISULFATE IN A FIRST EXTRACTION COLUMN AT A TEMPERATURE WITHIN THE RANGE OF ABOUT 20 TO 30% C. IN COUNTER-CURRENT WITH AN EXCESS OF ISOPROPYLETHER; ELIMINATING THE RESULTING EXTRACTION SOLUTION FROM THE HEAD OF THE FIRST EXTRACTION COLUMN, WASHING THE EXTRACTION SOLUTION WITH A SMALL AMOUNT OF WATER AND REMOVING THE SOLVENT FROM THE EXTRACTION SOLUTION BY VAPORIZATION; INTRODUCING THE RESULTING EXTRACT INTO THE MIDDLE PORTION OF A SECOND EXTRACTION COLUMN MAINTAINED AT THE SAME TEMPERATURE AS THE FIRST EXTRACTION CLUMB; INTRODUCING ABOUT DOUBLE THE AMOUNT BY WEIGHT OF ISOPROPYLETHER, CALCULATED ON THE AMOUNT OF EXTRACT, INTO THE LOWER PORTION OF SAID SECOND EXTRACTION COLUMN; INTRODUCING AT LEAST 15% BY WEIGHT WATER, CALCULATED ON THE AMOUNT OF ETHERAL SOLUTION, INTO THE UPPER PORTION OF THE SAID SECOND EXTRACTION COLUMN; SEPARATING THE EXTRACT INTO AN AQUEOUS LACTIC ACID-CONTAINING PHASE AND INTO AN ETHERAL PHASE CONTAINING ORGANIC BY-PRODUCTS; REMOVING THE AQUEOUS PHASE AT THE BOTTOM PORTION OF THE SECOND EXTRACTION COLUMN; AND VAPORIZING THE WATER CONTAINED IN AID AQUEOUS PHASE AND THEREBY CONVERTING IT INTO PURE LACTICE ACID OF ABOUT 90% STRENGTH.