Ammonium Bisulfate Catalyzed Dehydration of Beta-Hydroxy Acids

A process comprising the steps of:

• (A) Contacting in a reaction zone and under dehydration reaction conditions a beta-hydroxy carboxylic acid and/or its ammonium salt with a catalytic amount of a catalyst comprising ammonium bisulfate (ABS) to form a dehydrated carboxylic acid, water and ammonium sulfate (AS),
• (B) Removing a vapor stream comprising the dehydrated carboxylic acid and water from the reaction zone,
• (C) Removing a liquid stream comprising AS from the reaction zone,
• (D) Forwarding the vapor stream to a purification zone in which the dehydrated carboxylic acid is separated from water,
• (E) Forwarding the liquid stream comprising AS to a thermal conversion zone in which the AS is converted to ABS and ammonia,
• (F) Optionally, recycling the ABS from step (E) to step (A),
• (G) Optionally, recovering ammonia from the thermal conversion zone, and
• (H) Optionally, removing a purge stream comprising ABS and/or AS prior to or at or near the beginning of the thermal conversion zone.