As shown in Fig. 4, the crystal yield from crude DHSA decreased
with increasing temperature and solvent concentration, however,
the trend was opposite for purity. The interplay of various factors
on the final outcome of crystallization was addressed by Sutradhar
(2004). In this research, the process efficiency was determined to
optimize the solvent crystallization of DHSA with IPA. From Table 1,
crystallization of DHSA with 70% IPA at 20 ◦C was the most efficient
with a process efficiency of 69.3%.