Bio-based materials: Bio-based aromatics on the horizon

Global issues around security of supply and environmental impact have turned the focus on to producing 
aromatics using sustainable resources. However, bio-aromatics should not just be a replication of current products and processes, but instead should focus on new materials to improve not only green credentials but also performance, according to Florian Graichen, business development manager of Netherlands-based Biorizon.

Biorizon is a shared research centre with an initial focus on technology development for the production of bio-based aromatics for performance materials, chemicals and coatings. Graichen was speaking at the 13th World Aromatics and Derivatives conference in Berlin, organised by ICIS.

Rex Features Lignin from wood and other renewable sources will in future provide a source of complex aromatics

Biorizon has chosen to focus in particular on aromatics, seeing shifts in world petrochemical feedstocks as an opportunity. In particular the move to lighter cracker feedstocks globally and reduction in gasoline consumption and refining mean that aromatics prices are not only rising but also becoming more volatile. This should mean more focus on alternative sources of supply.

In addition aromatics are important precursors for a number of materials in the market particularly in the polymer and resins area. “There is still a huge gap to penetrate this market. Some 40% of chemicals, materials and coatings are [based on] aromatics. There is a big pull in demand,” said Graichen.

Interestingly, most investments in bio-materials to date have been driven by consumer trends and not necessarily by feedstock pressures; for instance, Coca-Cola’s use of the bio-based PET bottle, the PlantBottle, or BASF’s joint venture with Cargill and Novazymes to produce super-absorbent polymers from bio-based acrylic acid. These super-absorbent polymers are aimed at the consumer-focused diaper (nappy) market.

Replacement of traditional processes has not yet been a focus, with the bio-aromatics industry still immature. Interestingly Graichen does not see replacement of traditional processes as necessarily the future for the industry. “The industry is already moving to bio, especially in short lifetime plastics, but not so much in performance materials. We ­believe there is more potential in performance applications,” said Graichen.

Products already developed such as succinic acid or bio-based terephthalic acid tend to be more commodity and less in the area of complex specialty materials. Referring to Henry Ford’s famous quote on the market not asking for cars but instead wanting faster horses, ­Graichen went on to add: “Bio-based bulk aromatics are nothing but a faster horse. Specialties have a chance of producing a game-changing new material or new performance.”

Bio-based materials naturally have some advantages over traditional petrochemicals:

• A wider variety of atoms: petrochemicals are hydrocarbons with just two atoms dominating (carbon and hydrogen). Nature also clearly has substantial quantities of nitrogen and oxygen present.
• Wider variety of structures: petrochemicals usually come as linear chains or, in the case of aromatics, rings. Plant-based structures are more diverse and more complex.
• Chirality: petrochemicals have no chirality. Again nature is more varied. As a result of this chirality, Biorizon hopes to produce materials with new functionalities and new structures.

Biorizon is looking at an industry-inspired roadmap for the production of these products.

• Horizon 1: production of green cracker feed for use in existing crackers. Due by 2016.
• Horizon 2: production of benzene, toluene and xylenes by catalytic pyrolysis. Due from 2016-2019.
• Horizon 3: production of bulk and specialty aromatics using sugar/furan technology. Due from 2019-2022.
• Horizon 4: production of bulk and specialty aromatics using lignin technology. Due after 2022.

In addition, the Netherlands-based company sees a fifth horizon in the developments of co-products from the previous four horizons. This will generate added value and increase research efficiency.

Lignin is seen as the major aromatic resource of the bio-based economy. Lignin is a complex polymer of aromatic alcohols known as monolignols. It is most commonly derived from wood and is an integral part of the secondary cell walls of plants and some algae. Around 55m tonnes/year are produced as a side product of the pulping process.

Part of the push into lignin is the true sustainability of renewable feedstocks. Increasing food prices and global competition for land have led to a debate about whether feedstuff like sugar or corn should be used for the manufacture of fuel or chemicals.

Graichen himself mentioned the scandal of Indonesian forests being removed to grow more palm oil to supply the European bio-diesel market. “Renewability and sustainability have to go hand in hand. The amount of material needed in specialty applications is less. We are not trying to replace fuel in bulk use,” said Graichen.

In addition the lignin process is seen as more complex with a higher content of other elements such as oxygen, nitrogen or halogens. The output contains a large number of complex molecules. To some extent this is both the opportunity and the challenge.

“Cellulose liquid is a mess. Trying to turn it into chemicals is hard,” said Graichen. However the output is likely to be novel dimers, trimers, oligomers and polymers. The functionality of these can be maintained as designed by ­nature, or functionality can be added or ­removed. The result is likely to be a wide range of new materials, which should be increasingly ­specialised and high-performance.

• More information on Biorizon’s activities in bio-aromatics and its ­research community