Who would have thought twenty years ago that a humdrum chemical like ethanol would become the focus of major new commercial activity in ways not even imagined at that time. It all started when the U.S. government mandated that an oxygenated fuel must be blended into gasoline to achieve clean engine combustion to reduce formation of smog. This gave birth to a major ethanol-from-corn industry, supported by a Federal subsidy. In Brazil, some cars run on 100 percent sugar cane-derived ethanol, but in most countries car engines are not designed for that.
But it was soon realized that corn has serious drawbacks, both from an environmental standpoint and because the rapidly rising demand for corn for alcohol production made corn more expensive for the food-related market. So now it is likely that bio-ethanol will within a few years start being produced from cellulosic feedstocks like wood chips, grasses and waste materials.
Now, in an interesting case of “What goes around, comes around” ethanol will soon become a feedstock for a major ethylene derivative, replacing ethylene made fromhydrocarbons. Actually, fermentation alcohol was used before and during World War II to make ethylene in the U.S. and elsewhere to produce ethylene, butadiene and other chemicals before ethylene was made directly by cracking hydrocarbons. In Pernambuco, Brazil, in the 1950s, a chemical industry was created to make various ethylene derivatives from sugar cane alcohol. Eventually, ethanol lost its role as a chemical feedstock as ethylene became the largest petrochemical at a very attractive price.
Now for the turnaround! Dow Chemical and Mitsui & Co. recently teamed up in Brazil to build a complex that will effectively make polyethylene from sugar cane-based ethanol. This became a realistic proposition since crude oil-based naphtha, used in Brazil to make ethylene, has become quite expensive. Solvay, in a similar development, plans to produce polyvinyl chloride (PVC) from ethylene derived from corn-based ethanol
And in other news for ethanol, Celanese recently announced a process that is said to produce ethanol from natural gas, using its carbonylatio technology to make acetic acid, which is then hydrogenated to ethanol. The alcohol is aimed at the fuels market, though not in the U.S., where ethanol blended into gasoline must be produced from renewable raw materials. That could be done with biomass-derived synthesis gas.
With crude oil prices expected to stay high, there will be increasing interest to make “petrochemicals” from biomass. Let’s keep tracking this fascinating turnaround, while keeping in mind that regions where natural gas is cheap will continue as the low cost producers of basic petrochemicals.
Versatile ethanol: Fuel, chemical feedstock, smog fighter: Skol!