Chemical Makers Think Small

Nanotechnology developments are advancing along a broad front.

By Seán Ottewell, Editor at Large

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Nanotechnology is becoming increasingly important to chemical companies as they strive to improve processes and products.

BASF, Lugwigshafen, Germany, for one, maintains that nanotechnology is key to successful innovations in many of its different business areas — including energy, lighting, water treatment, health, electronics and automotive.


For example, the company is using nanostructures to develop efficent and flexible organic photovoltaics to convert infrared light into electrical energy. BASF also is relying on nano technology to improve organic light emitting diodes; it's developing a nanofilm that consumes 50% less energy than existing energy-saving lamps.

Nanotechnology also offers decisive advantages in water treatment, claims the company. Its ultrafiltration membranes with pores measuring about 20 nm enable filtering germs, bacteria and viruses from both process and drinking water.

In collaboration with Harvard University, Cambridge, Mass., the company is using nanotechniques to solve the riddle of how biofilms containing life-threatening infections grow and spread. The crucial processes here occur on the nanometer scale. In a similar vein, BASF also is investigating new nanoformulations for a range of medicinal substances, especially those that aren't readily soluble in water and, therefore, are poorly absorbed in the body after ingestion.

The company already offers nanoparticles for polishing the surface of wafers used in microchips. Also in the electronics sector, BASF is developing high-resolution nanometer-thin defect-free homogeneous layers that can be stacked together to create flexible displays.

In automotive, BASF has introduced a clearcoat in which, during curing, nanostructures form in the film through crosslinking — ensuring the clearcoat permanently retains its scratch resistance and still looks new even after many years.

However, crystalline nanostructures known as metal-organic frameworks (MOFs) have been generating most interest recently — as a way to store natural gas for vehicles. The three-dimensional MOFs contain nanosized pores that provide high porosity and vast internal surface area, allowing storage of comparatively large amounts of gas. Cars with fuel tanks with such MOFs may be able to travel twice as far on a single tankful as possible now, says the company.


BASF researchers have developed a solvent-free method for industrial-scale manufacture of aluminum MOFs (Figure 1).

"With the innovative production process, we can now manufacture MOFs by the tonne and in that way enable their commercialization," says Ulrich Müller, head of MOF research at the company's process research and chemical engineering division. Because the manufacturing process only uses water, avoiding organic solvents altogether, the method is said to be particularly safe and eco-friendly. "The high material yield also makes it very efficient," Müller comments.

As a result of its MOF work, in mid-September BASF received the Pierre Potier Prize. Initiated seven years ago by the two French chemical associations —Fédération Française pour les Sciences de la Chimie (FFC) and l'Union des Industries Chimiques (UIC) — the award honors innovations that support sustainable development.

BETTER REFINING CATALYSTS
"Nanotechnology has helped us to understand how we can make catalysts live longer and how we can make them more efficient," says Sergio Kapusta, chief scientist, materials, for Shell Global Solutions International, Amsterdam.

Important to this work is the company's close affiliation with Criterion Catalysts & Technologies, Houston.

"Advances in nanotechnology have helped us to optimize the active sites, which led to a next-generation Centera catalyst technology for hydrocracking pretreat," notes Raul Adarme, Criterion's general manager, hydrocracking. It assists refiners in increasing run length, processing more difficult feedstocks, or raising throughput (Figure 2). "Centera products are providing performance improvements in the start-of-run, weighted-average bed temperature of up to 14°C lower than previous-generation products," he adds.

"It is worth noting that Criterion's R&D is, in part, informed by the operational feedback received from Shell Global Solutions' customers. For instance, we provide a lot of feedback to the catalyst researchers about what to develop; we tell them what our clients need," explains Nicolaas van Dijk, Shell's global process technology manager, hydroprocessing.

"That input helps us to define what we need to aim for when we are developing next-generation catalysts," confirms Adarme.

Many new refineries outside the U.S. are designed for full-conversion hydrocracking to maximize diesel yields. And nanotechnology is playing a role in creating better catalysts. "… We have been working with the catalyst development teams to develop a new catalyst specifically for the second-stage service. We are in the process of commercializing this catalyst. The early indications are that it will unlock 6–7% more diesel from a two-stage hydrocracker compared with previous products," notes van Dijk.

"We have other approaches, too, for example in enhanced oil recovery. We use water for this and nanoparticles help us to tune the water for what is needed for each specific reservoir. We are also developing ways of using nanoparticles to relay information back from oil and gas reservoirs. So in the oil and gas industry we have used nanotechnology for many years, but we are really only at the start of the enormous potential that it has for us," Kapusta stresses.

MORE CATALYST INITIATIVES
The National Science Foundation (NSF), Arlington, Va., has added an extra three years and $12 million to its original commitment to the Center for Biorenewable Chemicals at Iowa State University, Ames, Iowa. In addition, the center's roster of industrial partners has swelled from the original six to 27 — including Ashland, Chevron Phillips Chemical and DuPont.

The center focuses on using nanotechnology to find new catalysts for making chemicals from biorenewable resources. To this end, it has brought together researchers who specialize in both chemical and biological catalysts to develop sustainable technologies.

Researchers have made significant progress in designing catalysts for converting pyrones to high-value chemicals, notes Robert Davis, a professor of chemical engineering at the University of Virginia, Charlottesville, Va., and head of the center's research into chemical catalyst design. The researchers also have developed technologies that convert carboxylic acids to alpha olefins used to make detergents and other chemicals, he adds.

Other researchers have used E. coli to produce the highest yields of carboxylic acids reported so far, says Jackie Shanks, a professor of chemical and biological engineering at Iowa State, who heads the center's microbial metabolic engineering research efforts. The researchers also have improved the ability of E. coli to resist the toxicity of the acids, she adds.

Meanwhile, the European Union has awarded €4 million ($5.1 million) to a new research project to develop carbon materials to replace the precious metals needed in catalysis. The research aims to make the production of chemicals and commodities greener, while enabling the European process industry to keep its worldwide competitive edge.

The project is called "Freecats — doped carbon nanostructures as metal-free catalysts." Nine European research institutions and technology enterprises are working on the project, which is being coordinated by the Norwegian University of Science and Technology, Trondheim.

"Metal-free materials with catalysis properties that are equally as good as precious metals do not exist naturally, so Freecats is aimed at developing new materials. Using nanotechnology, with atoms as building blocks, we can build carbon structures capable of binding or transforming substances in desired ways," explains Magnus Rønning of the university's department of chemical engineering, who is leading the effort.

One of the three applications chosen for Freecats is the production of light olefins. Demand for these chemicals is increasing globally, but the current use of platinum-based catalysts isn't seen as sustainable because they suffer from low selectivity and short lives and also are costly and polluting.

MORE ADVANCES
Action also is occuring in dendritic polymers or dendrimers. These are nanostructures that can be built atom-by-atom that hold great promise for applications in both biotechnology and pharmaceuticals. Effectively they marry a drug to a "container" that's then delivered with extreme precision to patients, overcoming the more scattergun approach of traditional delivery systems.

Dow Chemical, Midland, Mich., which was awarded the world's first patents on dendrimers following their discovery in its research labs in 1979, reached an agreement with Starpharma Holdings, Melbourne, Australia, and Dendritic Nanotechnologies (DNT), Midland Mich., earlier this year. It provides the two with ownership or access to Dow's dendrimer patent portfolio. Now, Starpharma has granted AstraZeneca, London, rights to test certain proprietary Starpharma oncology molecules.

Meanwhile, Dow Europe, Zurich, Switzerland, following the signing of a memorandum of understanding last year, is working with the Russian Corporation of Nanotechnologies (Rusnano), Moscow, to identify potential areas of cooperation for large-scale projects in areas such as energy efficiency, lightweight materials and life sciences. (Rusnano was established by the Russian government in 2007 with the aim of helping the country achieve annual sales of nano-enabled products of 900 billion Rubles ($28.6 billion) by 2015.)

For its part, ExxonMobil Chemical, Houston, is using nanotechnology to improve tire innerliners. Made from the company's proprietary Exxcore dynamically vulcanized alloy resin, the advanced innerliners are as light and thin as a plastic bag and require up to 80% less material than conventional innerliners. That can mean a weight reduction of as much as seven pounds for a passenger car. Moreover, they boast leading-edge inflation pressure retention loss rates, which help the tires handle better and last longer. The lower loss rates also reduce rolling resistance, leading to improved vehicle fuel economy and a corresponding reduction in carbon dioxide emissions.

ExxonMobil expects further nanotechnology developments to increase the amount of halobutyl rubber in its innerliner formulations — for even better air retention and performance.

 


Seán Ottewell is Chemical Processing's  Editor at Large. You can e-mail him at sottewell@putman.net.

 

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