Linear alcohols, such as butanol, hexanol and octanol are widely used in coatings, adhesives, surfactants, detergents, lubricants, cosmetics and many other products, as well as fuels. Typical industrial methods for producing these alcohols rely on fossil resources and low-selectivity mechanisms that lead to inefficient side reactions and byproducts. Catalyxx Inc. (St. Louis, Mo.; www.catalyxxinc.com) is commercializing a new catalytic route to produce drop-in, cost-competitive and carbon-negative butanol, hexanol and octanol from biomass-based ethanol. Catalyxx’s proprietary catalytic platform is based on the well-known Guerbet reaction, where two molecules of ethanol are combined to make one molecule of butanol and one molecule of water, and progresses to combine butanol and ethanol into hexanol, and subsequently hexanol and ethanol to make octanol. “This is a reaction that is very well-known, but it has previously been very difficult to avoid all the side reactions that happen during the condensation. In the past when you were doing the Guerbet reaction, you were making some linear alcohols, but also all types of branched alcohols, aldehydes, ketones and esters. This leads to a mixture of products that is really complicated to separate,” explains Joaquín Alarcón, CEO of Catalyxx.
Source: Catalyxx
Catalyxx has developed the first industrial catalyst that introduces selectivity for linear alcohols into the Guerbet reaction and avoids the unwanted side reactions. And although the Catalyxx technology uses bioethanol as a feedstock, its platform requires only thermochemical processes and no fermentation or other biological steps, making it simple to integrate into existing facilities. The process can handle ethanol from any source, including biomass like sugarcane, beetroot, corn or cellulosic materials, as well as ethanol from other sustainable sources like CO2 capture/utilization or electrochemical routes.
“Our multifunctional metal-oxide catalyst has a combination of acid and basic characteristics, with hydrogenation and dehydrogenation capabilities to facilitate the first and last step of the condensation reaction. This is heterogenous catalysis in a fixed-bed reactor, so not an extremely complicated process setup,” explains Alarcón. The process results in no waste, and the only other product is water, which is treated and reused, resulting in a zero-discharge system.
Catalyxx recently selected Sines, Portugal as the location for the company’s first commercial-scale plant, slated to produce butanol, hexanol and octanol. Construction is expected to begin later this year, and demand from industry customers already well exceeds plant capacity. Catalyxx also operates a demonstration facility in Sevilla, Spain. “We have operated that facility for more than 10,000 hours. Of those, 2,700 hours have been nonstop, continuous operation, where we have tested the performance of the catalyst, process stability and production of the different products. In total, we have put in more than 140,000 hours of testing,” notes Alarcón. Future plans involve plants in Brazil and the U.S. and a licensing model or global customers. A biorefining company in India is the first licensor for the technology.