Clarification of propylene glycol monoester polymorphism

A minor revision based on new data is reported for the polymorphism of 1‐propylene glycol monopalmitate and monostearate. Metastable Form I is now found to be intermediate in melting level between α and stable Form II. Form III as previously reported transforms to α below the α mp. For the 80:20 mix of 1‐propylene glycol monostearate‐2‐propylene glycol monostearate, the approximate equilibrium mixture, it is again observed that Form II is stable, melting a little above α; and Form I transforms to α slightly below the α mp; and Form III is missing.