Piperylene sulfonate

As described in earlier chapters, the volatility of solvents is of crucial important in their applications. In 2007, the groups of Liotta, Eckert and Jessop first reported on the formation and use of piperylene sulfone (PS) as a recyclable alternative to dimethyl sulfoxide (DMSO) (Figure 9.11). DMSO, in addition to dimethylformamide (DMF) and hexamethylphosphoramide (HMPA), is a widely used dipolar, aprotic solvent. However, it is difficult to remove from products by distillation and is rarely recycled. In contrast, PS decomposes cleanly at temperatures above 100°C to give ra -l,3-pentadiene and sulfur dioxide, which reform PS at room temperature (Figure 9.11). 

The checkers consistently obtained a slightly higher melting point (uncor.) in the range 64.4-65.4°. The purified cyclic sulfone serves as an ideal intermediate for the preparation of extremely pure isoprene, since the latter can be regenerated nearly quantitatively at 135-140°. Other sulfones that can be prepared by this method and that are uscfid in the purification of dienes are those of butadiene, m.p. 65.5°, and 2,3-dimethyl-butadiene, m.p. 135°. The sulfone of piperylene is a liquid. ... 

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