Acrylics are an extremely varied and useful group of chemicals used in all types of products, from nail polish to diapers. Presently, a team of scientists from the University of Connecticut (UConn) and ExxonMobil explain a new process for producing them. The new technique, reported in the February 8th issue of Nature Communications, would boost energy efficiency and decrease poisonous by-products.
The international market for acrylic acid is huge. According to industry group PetroChemicals Europe, the world used nearly 5 million metric tons of it in 2013. This is because acrylics and the closely connected acrylates are the building blocks for numerous kinds of paints, plastics, textiles, dyes, glues, and papers. Strung together in lengthy chains, they can create all kinds of beneficial materials. Acrylate mixed with sodium hydroxide, for instance, makes a highly absorbent material used in diapers. Incorporate extra methyl groups (carbon plus three hydrogens), and acrylate can make Plexiglass.
The existing industrial processes for manufacturing acrylics require high temperatures of nearly 450 °F, and create undesirable and at times unsafe by-products, such as carbon dioxide, ethylene, and hydrogen cyanide.
UConn chemist Steve Suib, director of the University’s Institute for Materials Science, and colleagues at UConn and ExxonMobil have engineered a new method of creating acrylics at mild temperatures. Their method can be finely tweaked to prevent the creation of undesirable chemicals.
Scientists at ExxonMobil Research & Engineering partnering with professor Suib’s group in UConn have been probing new technologies that can lower energy intensity, skip steps, improve energy efficiency, and reduce CO2 footprint in the production process of acrylic. The recent publication in Nature Communications describes discovery of a new route to produce a class of acrylate derivatives in potentially fewer steps and with less energy.
Partha Nandi, Chemist, ExxonMobil.
The method uses a porous catalyst composed of oxygen and manganese. Catalysts are materials used to accelerate reactions. Mostly, they offer a surface for the molecules to rest on while they react with each other, aiding them to meet up in the appropriate configurations to accomplish the deed. In this case, the pores meet that role. The pores are 20 to 500 Å wide, sufficiently big for moderately large molecules to fit inside. The manganese atoms in the material can trade their electrons with neighbouring oxygens, which makes it easier for the appropriate chemical reactions to take place. Based on the starting ingredients, the catalyst can facilitate all varied types of acrylics and acrylates, with limited waste, Suib says.
“We hope this can be scaled up,” he says. “We want to maximize yield, minimize temperature, and make an even more active catalyst,” that will help the reaction speed up. The team also learned that incorporating a tiny amount of lithium helped accelerate things up, too. They are presently studying the precise role of lithium, and experimenting with ways of enhancing the oxygen and manganese catalyst.
This study was sponsored by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Chemical, Biological, and Geological Sciences under grant DE-FG02-86ER13622.A000, as well as ExxonMobil.