Production of formic acid from its salts

Claim 1

IN A PROCESS FOR THE PRODUCTION OF FORMIC ACID FROM ITS ALKALI SALTS, WHICH COMPRISES REACTING AN AQUEOUS SOLUTION OF THE FORMIC ACID SALT WITH AN ACID MEDIUM SELECTED FROM THE GROUP CONSISTING OF MINERAL ACIDS AND ACID SALTS OF MINERAL ACIDS, EXTRACTING THE FREE FORMIC ACID FROM THE REACTION MIXTURE THUS OBTAINED WITH A SOLVENT MIXTURE WHICH READILY DISSOLVES THE FORMIC ACID, HAS A BOILING POINT DIFFERING FROM THAT OF FORMIC ACID AND DOES NOT FORM AN AZEOTROPIC MIXTURE WITH FORMIC ACID, SAID SOLVENT MIXTURE CONTAINING AN EXTRACTION MEDIUM FOR FORMIC ACID WHICH IS SOLUBLE IN WATER AND A COMPLETELY WATER IMMISCIBLE AUXILIARY LIQUID, THE STEPS WHICH COMPRISE ADJUSTING THE QUANTITY OF SUCH AUXILIARY LIQUID THAT A 60 TO 70% AQUEOUS SOLUTION OF FORMIC ACID IS EXTRACTED BY THE SOLVENT MIXTURE, FRACTIONALLY DISTILLING THE EXTRACTION PRODUCT TO SEPARATE THE AQUEOUS FORMIC ACID FROM THE SOLVENT MIXTURE AND SUBJECTING THE AQUEOUS FORMIC ACID TO AZEOTROPIC DISTILLATION TO SEPARATE THE FORMIC ACID FROM THE ACCOMPANYING WATER.