OPXBIO
BUSINESS
of low-cost ethane extracted from shale deposits, cracker operators are favoring naturalgas-based feedstocks over petroleum-derived ones. Cracking natural gas yields less coproduct propylene, causing its price to go up. This presents an opening for biobased processes, Tittle explains. But France’s Arkema serves as an example of how tough competing with the established acrylic acid process will be. In 2010, the specialty chemical company started HARD WORK OPXBio a pilot plant for converting scientists are working biobased glycerin into acrylic toward a biobased route acid. Executives had high to acrylic acid through hopes for the process because, 3-hydroxypropionic acid. just as in the propylene-based route, it makes acrolein as an intermediate. Arkema got the glycerin-based process ready for full-scale manufacturing but then put it on hold after concluding that it can’t, at present, compete with the propylene route. “The question is the cost of glycerin,” says Marie-Pierre Chevallier, Arkema’s group vice president of acrylics. Companies vie for a NONPETROCHEMICAL ROUTE into Glycerin is a by-product of convertthis lucrative industry ing triglycerides from fats and oils into ALEXANDER H. TULLO, C&EN NORTHEAST NEWS BUREAU biodiesel fuel. In the mid-2000s, when Arkema was developing its process, biofuels were booming and glycerin was being they do currently for raw materials. So while churned out left and right. “The vision that CHEMICAL AND BIOTECH firms are comthe potential market is luring giants such existed at that moment in time was that peting to meet one of the biggest challengas Dow Chemical and BASF, as well as newthe market for glycerin would be oversupes in biobased chemicals: an alternative to comers OPX Biotechnologies, Myriant, and plied,” Chevallier says. But the glut turned propylene-derived acrylic acid. The global Metabolix, these companies are aware that out to be only temporary. market is worth billions of dollars, but it’s beating the economics of the petrochemical The acrylic acid supply chain won’t tolnot just money that companies are after. route, which has had a 40-year head start, erate higher costs, Chevallier acknowledgAlso at stake are the bragging rights for won’t be easy. es. “We are not in a situation where a P&G making consumer products such as diapers Propylene established itself as the or any company manufacturing diapers at and paints more sustainable. About 5 million metric tons of acrylic dominant raw material for acrylic acid in the this moment is ready to pay a 15% premium acid will be produced globally this year us1960s. That’s when chemical firms found because it is a biobased raw material,” she ing a petroleum-based process, according an alternative to the Reppe process, which says. “This is because no consumer is ready to William L. Tittle, a principal with the combined acetylene, carbon monoxide, and to pay a premium for the diaper.” consulting group Nexant. More than half of water to make acrylic acid. In the replaceit will be reacted with alcohols to make acment process, they oxidize propylene to OTHER FIRMS DEVELOPING biobased rylate esters, used in acrylic paints. Most of make acrolein, which is oxidized further to processes are undeterred. “We wouldn’t be the rest will be polymerized into polyacrylyield acrylic acid. in this if we didn’t believe that the process ic acid, the backbone of the superabsorbent Today, though, propylene is a problem we’re developing has the long-term popolymers used in disposable diapers. for acrylic acid makers, particularly in the tential to have good economics relative to Procter & Gamble and other diaper makU.S. The compound is primarily made as propylene-based acrylic acid,” says Charles ers would love to feature polymers derived a coproduct in the ethylene crackers that R. Eggert, OPXBio’s chief executive officer. from plants, instead of petroleum, as part of line the Gulf Coast. Thanks to the advent In the short term, customers may be a green marketing campaign. But chemical executives know that such cost-conscious consumer firms won’t pay much more than
SUSTAINABLE ACRYLIC ACID
“Most of the R&D homework is done.”
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willing to pay an “early-stage innovation premium” for biobased acrylic acid, Eggert says, not unlike how tech-savvy consumers pay more to be the first to purchase the latest smartphone. Longer term, as companies gain experience with biobased processes, costs will fall in line with propylene-based acrylic acid, he predicts. To this end, OPXBio has been working on a fermentation route to make acrylic acid from sugar via the intermediate 3-hydroxypropionic acid, or 3-HP.
the transition to larger-scale manufacturing has thus far been smooth. Eggert hopes to start commercial production in 2017. Cargill, which has been making biobased chemicals for more than a decade, also hopes to enter the acrylic acid business with a 3-HP process. The company has been working with the industrial biotechnology specialist Novozymes since 2008. BASF, the world’s largest acrylic acid producer, joined the effort last year. The partners demonstrated kilogram-
Lactic acid process
ROAD MAP Chemical and biotech firms can use many routes to make acrylic acid.
Sugar Fermentation
O
Glycerin process HO
OH
Conventional process
OH
OH
HO
Lactic acid
O2
Glycerin O 2 H2O
Propylene
O H2O
H Acrolein
O2
O2
O
H Acrolein
H2O
HO H2O
3-HP process
Acrylic acid
quantity production of 3-HP earlier this year and plan to scale up the entire OH HO process next year in fermentation vessels of up to 80,000 L. “Most of the 3-Hydroxypropionic acid (3-HP) R&D homework is done,” says Christian Weinel, head of the biobased acrylic acid Fermentation program at BASF. Sugar Weinel is confident that customers will The learning curve has been steep. “Getline up to buy biobased acrylic acid derivating the pathway to make some hydroxytives once they are ready. “A pioneering projpropionic acid happens fairly readily,” says ect like this, of course, requires a strong marDavid A. Hogsett, the firm’s chief technolket pull,” he says. “So far we have received ogy officer. “Making sure you can do it in the very positive feedback and interest from yields and the speeds and the product concustomers across different industries.” centrations that are necessary turns out to be what you spend most of your time on.” BEST KNOWN FOR commercializing For the process of dehydrating 3-HP into succinic acid, another biobased chemical, acrylic acid, OPXBio has teamed with Dow Massachusetts-based Myriant is developChemical. The pair has already made small ing a route to acrylic acid that runs through quantities of high-purity glacial acrylic sugar-derived lactic acid. Myriant Presiacid, which is used to make superabsordent and Chief Operating Officer Cenan bent polymers, for customer sampling. Ozmeral sees an advantage over the 3-HP OPXBio is currently making 3-HP in route. “It is much cheaper to make lactic 3,000-L fermentation vessels and plans to acid at very high yields and at very high scale up to fermenters as big as 50,000 L concentrations than 3-HP,” he says. within the next year. Officials say they’re There is a catch. With its terminal hyconfident about the scale-up, given that droxyl group, 3-HP is easier to dehydrate O
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than lactic acid, also known as 2-hydroxypropanoic acid. Myriant worked with chemists from Massachusetts Institute of Technology and Pennsylvania State University to develop catalysts that provide 90% conversion of lactic acid and 80% selectivity for acrylic acid. Ozmeral hopes to soon get selectivity up to 90% so Myriant can advance to pilot-plant production next year. For commercialization, Myriant would seek a partner. This is similar to how the company went about commercializing succinic acid. In that business, the company locked arms with Johnson Matthey Davy Technologies on a process to make butanediol via succinic acid instead of the traditional maleic anhydride. One more contender in plant-derived acrylic acid is another Massachusettsbased biotech firm, Metabolix. Having made its mark by producing polyhydroxyalkanoate polymers in microbes, Metabolix wants to use a polymer as an intermediate for acrylic acid. The company’s process involves engineering microbes to express poly(3hydroxypropionate), or P3HP. It then dries off the water to get solid biomass. When this biomass is then heated, P3HP vaporizes into acrylic acid. “We don’t have to fish a molecule out of a broth,” says Max Senechal, vice president of biobased chemicals for Metabolix. One advantage the process has over other routes to acrylic acid is logistics, according to Senechal. Shipping acrylic acid long distances is tough because it can polymerize along the way. In Metabolix’s process, dry biomass containing P3HP can be shipped to a customer, allowing for recovery of the reactive monomer on-site. Biobased processes will need every advantage they can get if they are to succeed against the entrenched propylene route. They need to be proven technically and scaled up before customers will be willing to swap propylene for sugar, and this will take years. Making a biobased move is even more of a gamble because in a few years the propylene supply pendulum could reverse. Energy companies are increasingly finding propane in shale gas, and in the U.S. alone, a half-dozen facilities are planned to dehydrogenate propane into propylene. Within a few years, they could increase supply of the chemical and lower its price. As Arkema’s Chevallier knows all too well, competing with a chemical route is no sure thing. ◾
