In recent years, however, companies such as DuPont are investing in the biological production of PDO using renewable feedstocks such as corn.
[1][2] In May 2004, DuPont and Tate & Lyle announced that they would start up a joint venture to build a facility that produces polymers from renewable feedstock instead of petrochemicals.
[1] In particular, their goal was to design a fermentation system that converts corn sugar into PDO (propanediol manufactured in this way is referred to in the media as "BioPDO").
They argue that using such a bioprocess is more energy efficient than conventional petrochemical processes (conversion of propylene into propanediol) because the bioprocess has four advantages over the conventional process: smaller environmental footprint, lower operating costs, smaller capital investment, and greater sustainability due to use of renewable corn feedstock.
[4] The low-pressure steam is then compressed to a higher pressure and temperature, and afterward directed to the outer casing of the flash evaporation unit to heat the system.
[4] The three main types of chemicals in the fluid at this stage of the separation are water, BioPDO, and impurities such as glycerol, sugars, and proteins.
[4] To achieve greater purity, the BioPDO distillate of the second column is sent to a hydrogenation reactor to convert the remaining polymer-coloring impurities into non-coloring chemicals.