Process for the manufacture of methacrylic acid esters from acetone cyanhydrin

Claim 1

A PROCESS FOR SYNTHESIZING METHACRYLIC ACID ESTERS FROM ACETONE CYANHYDRIN, WHICH COMPRISES REACHING A QUANTITY OF ACETONE CYANHYDRIN WITH A COMPOUND SELECTED FROM THE BORIC ANHYDRIDE AND PYROBORIC ACID UNDER SUBSTANTIALLY ANHYDROUS CONDITIONS AT A TEMPERATURE OF APPROXIMATELY 50* C. TO PRODUCE A BORATE PRODUCT, MIXING FROM 1.2 TO 1.6 MOLS OF STRONG MINERAL ACID WITH SAID BORATE PRODUCT PER MOL OF STARTING ACETONE CYANHYDRIN AT A TEMPERATURE OF BETWEEN 60* AND 80* C. TO PRODUCE AN ACIDIFIED MIXTURE, MIXING APPROXIMATELY ONE MOL OF WATER PER MOL OF STARTING ACETONE CYANHYDRIN WITH SAID ACIDIFIED MIXTURE AND HEATING THE RESULTING MIXTURE TO A TEMPERATURE BETWEEN 120* AND 160* C. FOR A PERIOD OF FROM 1 TO 5 MINUTES TO PRODUCE A REACTION MIXTURE CONTAINING A QUANTITY OF METHACRYLAMIDE APPROXIMATELY EQUAL TO THAT THEORETICALLY PRODUCIBLE FROM THE STARTING QUANTITY OF ACETONE CYANHYDRIN, COOLING SAID REACTION MIXTURE TO A TEMPERATURE OF APPROXIMATELY 60* C., MIXING AN ALCOHOL WITH THE COOLED REACTION MIXTURE AND REACTING THE ALCOHOL WITH THE METHACRYLAMIDE TO PRODUCE THE METHACRYLIC ACID ESTER OF THE ALCOHOL, AND RECOVERING SAID ESTER.