Purification and separation of durene by static melt crystallization

The purification and separation of durene from the mixture containing durene isomers were studied. Since the boiling points of tetramethyl benzene isomers are very close but their melting points are of great differences, static melt crystallization was applied to separate and purify durene from its isomers. Crystallization experiments were carried out under various operating conditions. The effects of cooling rate, crystallization temperature, sweating temperature and sweating time on the yield and purity of crystal were investigated. Orthogonal experimental design method was adopted to analyze the factors that may affect the yield of durene. Under the optimal crystallization conditions, the purity of durene could reach as high as 99.06% with the yield of 75.3% through one crystallization process. By fitting purification data based on sweating time in isothermal operations, the purification rate coefficient was obtained.