Ethylene and propylene, the two most important olefins, are used as feedstock for chemicals and polymers. They are co-produced in steam crackers and refineries, though their relative ratio is determined by feedstock used and severity of the 'cracking'. Gas crackers that process ethane-rich gas, produce more of ethylene than propylene, while processing of refinery streams by fluid catalytic cracking (FCC) can produce more of propylene than ethylene. About 70% of the propylene comes from steam cracking, 25% from FCC and 5% comes from alternate or 'on-purpose' processes. In the Asia-Pacific, where refineries still continue to be built, FCC propylene represents a growing and significant chunk of total propylene capacity. Europe and North America have significant production of propylene from refineries, but lack of investments in new refineries implies little scope for increasing propylene output. In the Middle East, development of petrochemicals has been dependent on massive ethane-crackers, neglecting propylene and its derivatives. Globally, more than 25% of new crackers that started up between 2003 and 2007 were based on ethane and produce little propylene. While the projected annual demand growth for ethylene is at about 3%, propylene is expected to see faster growth at 4-5%, driven by strong demand for polypropylene (PP) in emerging markets. Steam cracker expansions/additions cannot keep pace with propylene demand growth. While ethylene growth will be largely satisfied by new 'mega-crackers' being built in the Middle East, their feedstock (primarily ethane), will again make them poor sources of propylene. Though propylene demand is only about half of ethylene, the world is heading to a shortage of propylene from conventional sources. Technology has been developed to produce propylene from renewable sources such as biomass. Propylene generated from biomass is called green propylene. There are essentially two technology approaches. They are Biochemical and Thermochemical. The biochemical approach uses biomass-based sugars to ferment into ethanol (and alternatively to butanol). A variety of materials can be used for fermentation, such as corn starch, sugarcane, sugar beet, etc, depending on the availability for large-scale production. Corn is the most common raw material in the U.S., however, sugarcane can be more cost-effective than corn in tropical countries such as Brazil, India, China, Thailand and Pakistan. The use of enzymes to convert biomass into ethanol is a mature and proven technology. There is still potential for improvement for the use of enzyme technology to optimize and improve the production of ethanol. On the other hand, fermentation to butanol needs some further development to get to a mature level. Once alcohols (ethanol and butanol) are obtained, they must be processed to olefins, ethylene and butene respectively; then combined in the metathesis step, where ethylene and butene’s bonds are broken and rearranged into propylene. Ethanol dehydration, butanol dehydration, ethylene dimerization and metathesis are all commercially available technologies, but are mostly used for applications other than manufacturing green propylene. Thermochemical technologies can use heterogeneous material as feedstock, using heat to convert these carbon-rich materials into gas (called syngas) in the gasification step, which is a crucial component of a thermochemical technology platform. Several companies market different biomass gasification technologies. The syngas obtained is then purified so it can be transformed into products such as methanol and ethanol, which, in turn, will be further processed to propylene. The most common technology used to accomplish that last step is the methanol-to-propylene (MTP) technology, which is, along with the syngas-to-alcohol technology, commercially available. Some companies license the entire thermochemical chain in individual technology parts. Thermochemical routes are less affected than biochemical in the raw material costs. Combined thermochemical and biochemical technology development in which the more complete use of the biomass to produce propylene has been achieved. Sugar/starch will be fermented to ethanol and the cellulosic part (sugarcane bagasse or corn straw) would be gasified to syngas. Both ethanol and syngas would then be reacted together to produce propanol which, in turn, would be dehydrated to propylene. Such a technology combination is still under development, but it is promising, since less biomass would be required to produce the same amount of the green propylene resulting in less land used, lower capital and operating costs. A greener process to turn propane into industrially necessary propylene, eliminating the expense and the environmental hazards has been developed by the US Department of Energy’s Argonne National Laboratory. Using platinum clusters, the team devised a way to catalyze propane, not only in a more environmentally friendly way, but also using far less energy than previous methods. Alkanes are typical feedstocks for transformation to alkenes, aromatics, and chemicals containing value added moieties. Dehydrogenation is a route to such transformations, but it is an endothermic process requiring significant energy input. Oxidative dehydrogenation (ODH) of propane to propylene is a multibillion dollar industrial process. ODH of alkanes is exothermic, and thus an attractive alternative to dehydrogenation. However, current ODH catalysts have limited activity and/or poor selectivity, resulting from inability to prevent complete oxidation. Two classes of catalysts see use: Vanadia and platinum. The vanadia based catalysts are highly selective, but their activity is relatively low. Pt-based catalysts are more active, but their selectivity is low. Argonne scientists showed the size pre-selected Pt8-10 clusters stabilized on high-surface-area supports are 40-100 times more active for the oxidative dehydrogenation of propane than previously studied platinum and vanadia catalysts, while at the same time maintaining high selectivity toward formation of propylene over by-products. This new class of catalysts may lead to energy-efficient and environmentally friendly synthesis strategies and the possible replacement of petrochemical feedstocks by abundant small alkanes. The oxidative dehydrogenation of alkanes is a reaction that is exothermic and thus an attractive alternative to the endothermic process of dehydrogenation of alkanes. The endothermic process requires a significant energy input with an increased chance of environmentally unfriendly by-products. (References: Chemsystems, Felipe Tavares and Aldemir Marreiros, Intratec Solutions LLC)