Determination of the Solid–Liquid Phase Diagram of the Binary System Acrylic Acid + Propionic Acid

In this work, the solid–liquid equilibrium of the binary system acrylic acid (AA) + propionic acid (PA) has been determined by two different methods: analytical and synthetic methods. The phase diagram of AA + PA we obtained exhibits an eutectic behavior, a peritectic point, and a peritectic compound which has never been identified before. Current crude biobased AA contains a higher proportion of PA than AA from petrochemical origin. The determined phase diagram is favorable to the implementation of melt crystallization, and good theoretical yields can be assumed for the production of AA with a high purity.