*2.3.2 Diols*

In addition to methanol, ethanol and propanol [46], the hydrogenolysis of glycerol can lead to formation of ethylene glycol (EG) and propylene glycol (PG, 1,2-propanediol and 1,3-propanediol) (**Figure 1**) [47]. It is worth mentioning that diols can also be obtained from thermochemical conversion of fructose in the presence of homogeneous osmium and ruthenium catalysts [48] and from cellulose using a nickel-tungsten carbide catalyst [49]. Recently, Sappi Ltd. acquired Plaxica's Xylex® technology which they plan to utilize in valorizing the hemicellulose component of their pulp processing waste, in producing, furfural and xylitol [50]. Changchun Dacheng Industrial Group operates a commercial integrated biological and thermochemical process that manufactures EG, PG

and 2,3-butanediol (2,3-BDO) from starch. Ten thousand tons of 2,3-BDO are produced annually [51].

Diols serve as dehumidifying and antifreeze agents. They have important applications as monomers (in polyester production) and work as solvents in the cosmetic and coating (varnishes and waxes) industries [46, 49].
