Abstract
Companies are increasingly leading the move away from products which are harmful to workers, customers, and the environment. Hazardous chemicals are a risk-management issue, and regulatory pressures are forcing companies to consider replacement of chemicals such as solvents.
In response to this need, Circa Group was set up in 2006 to create safer and more sustainable chemicals. By providing biobased, non-toxic, high-performance alternatives from cellulose, the company is also addressing a gap in the market as millions of tonnes of cellulose are under-utilized every year.
Circa's proprietary FuracellTM technology is the world's first continuous process to produce levoglucosenone, a versatile platform chemical. Efficient and flexible, the process is highly selective for levoglucosenone, producing minimal by-products. Circa is constructing a portfolio of derivative products and licensable IP from levoglucosenone, across a number of growing specialty chemical sectors such as biosurfactants, flavors, agrochemicals, biopolymers and biosolvents—including novel solvent CyreneTM.
A Safer, More Sustainable Solvent
Environmental, health, and safety concerns have increased interest in and demand for greener solvents. Despite REACH and other chemical legislations, few biobased solvent solutions have been established. Replacing solvents is indeed resource-consuming as there is no such thing as a drop-in replacement. Developing new solvents involves process trialling, optimization and product regulatory approvals, and Cyrene is one of the few, new biobased solvents on the market.
Made from certified and renewable cellulose waste from papermaking and forestry operations, Cyrene was developed by Circa in conjunction with the Green Chemistry Centre of Excellence (GCCE) at the University of York, UK, with a focus on the one million tonne dipolar aprotic solvent market in the speciality chemical and pharmaceutical industries.
A chiral dipolar aprotic solvent, Cyrene is a biobased alternative to polar aprotic solvents such as N-methyl-pyrrolidone (NMP), and N,N-dimethylformamide (DMF), which are under regulatory pressure worldwide due to their toxicity. Cyrene has been shown to be readily biodegradable and exhibits an improved Health, Environment and Safety (HES) profile compared to NMP and DMF. Crucially, Cyrene is not classified as reprotoxic, unlike NMP, DMF and Dimethylacetamide (DMAc), which are on the candidate list of the EU's Substances of Very High Concern (SVHC). A recent NMP restriction also means that after May 2020 its use will be further regulated, and it will not be able to be manufactured or used in the EU unless operational conditions are maintained to ensure that exposure to workers is below specified levels.
Cyrene is produced from waste sawdust, and by using lignocellulosic waste as a feedstock, a much lower carbon footprint is created compared to traditional solvents. Independent life-cycle analysis has also shown that production of Cyrene using Circa's Furacell™ process is almost greenhouse gas neutral—something that is impossible to achieve with petrobased chemicals.
Cyrene has a unique property set, including viscosity, surface tension and polarities, which makes it an attractive solvent for producing a wide range of products including advanced materials.
Graphene, Polymers and Other Cyrene Applications
Recent studies have found that Cyrene outperforms traditional solvents in the production and dispersion of graphene. The highest-quality conductive graphene ink ever, which used Cyrene instead of NMP, was recently confirmed in a study by the University of Manchester. 1
Additionally, The University of York and the Spanish National Research Council (CSIC) found that Cyrene had “near-ideal physical properties for graphite exfoliation and the production of graphene dispersions” 2 as a 13-fold increase in graphene loading could be achieved by switching from NMP (the solvent of choice) to Cyrene. Graphene produced in Cyrene was also found to be of significantly higher quality, with 93% of flakes comprising of 10 layers or less as well as having a greater aspect ratio and much lower edge defects.
These findings have far-reaching commercial applications as they open up market opportunities for graphene in applications such as advanced composites and polymers, coatings, batteries and supercapacitors, 3-D printed materials, and functional fluids. More specifically, graphene inks can directly be applied to materials like textile and paper and used in many applications including transistors, sensors, antennas, radio frequency identification (RFID) tags and wearable electronics.
Cyrene can also be a suitable alternative for NMP and DMF in the production of polymers used in the paints and coatings industries. Cyrene has been successfully applied in the production of polyamideimides (PAIs), used in a wide range of applications including the production of electrical wire insulation (wire enamel). Both the polymerization and curing of this polymer can be done using Cyrene. Additionally, using Cyrene instead of NMP as a solvent for the polycondensation of carboxylic acid anhydrides and diisocyanates facilitates rapid curing and provides coatings with enhanced solvent resistance.
Cyrene was also recently tested as a paint stripper to remove common paints and graffiti from various porous materials. An extensive range of solvents was tested as part of a project supported by the UK innovation agency, and Cyrene was shown to successfully clean the materials tested in this study and compared favorably against commonly used solvents for this specific application.
Like traditional dipolar aprotic solvents, Cyrene is miscible in water and has high flash and boiling points as well as low vapor pressure. However, Cyrene does not contain any nitrogen or sulphur heteroatoms, which are normally present in polar aprotic solvents and associated with some of the issues faced by dipolar aprotic solvent (e.g. reprotoxicity, NOx and SOx emissions).
FC5 Commercial Demonstration Plant Now Online
Cyrene and levoglucosenone are currently produced at FC5, Circa's prototype plant which recently came online. Constructed in partnership with Norwegian pulp and paper company Norske Skog, FC5 is an AUD$6.5 million (USD$4.6 million) (commercial demonstration plant based in Tasmania, Australia. FC5 was also supported by the Tasmanian government through a AUD$1.5 million grant.
At FC5, Cyrene is produced in one step from levoglucosenone derived from sawdust through the Furacell process, which can also be applied to other types of cellulosic biomass feedstock including straw and bagasse. When heat is applied to cellulose in the presence of a catalyst using Circa's process, levoglucosenone is selectively produced. This reduces downstream separation processes and consequent waste disposal and the solid char generated, as a by-product of the process, provides enough energy to run the Furacell process.
The Furacell patent has so far been granted in China, Japan, Singapore, United States, Israel, South Korea, Australia, and New Zealand. Other key markets are underway. Circa has also recently been granted authorization by the European Chemicals Agency (ECHA) to manufacture or import up to 100 tonnes/year of Cyrene in the European Union, after receiving REACH Annex VIII approval.
Circa's Portfolio
Beyond levoglucosenone and Cyrene, Circa is developing a portfolio of higher value products such as flavors and fragrances, pharmaceuticals and agrochemicals actives and specialty polymers. For example, Circa has developed, in collaboration with AgroParisTech in France and the University of New England in Australia, a patented process to produce a flavor with a powerful dairy note called Dairy Lactone. This flavor can, amongst other things, be used to enhance the flavor of non-dairy products.
Collaboration is Key
Circa partners with experts in universities and companies worldwide to develop its products and technologies. This approach has cost-effectively delivered several patented products and processes which Circa owns or has exclusive options to commercialize.
Distributors Will&Co and Sigma/Aldrich ensure Cyrene and levoglucosenone are available to researchers in academia and industry across the world.
Circa is a consortium partner of EU Horizon 2020 project ReSolve, which aims to replace petrobased solvents with biobased solutions. The three-year project is aiming to replace traditional, fossil-based solvents categorized as substances of very high concern (SVHC) under European REACH regulation. ReSolve is set to produce and demonstrate production of novel alternatives to replace toxic solvents toluene and NMP, create an additional pipeline of biobased solvents, establish a toxicological safety testing strategy and evaluate possible production processes of the most advanced biobased solvent candidates, benchmarked against conventional solvents.
Alongside a number of UK-based companies, Circa is also a partner on R2LIB (Reclamation, Remanufacture of Lithium Ion Batteries), a project funded by Innovate UK to develop an industrial-scale automotive battery recycling scheme in the UK.
A Biobased and More Sustainable Future
As production volumes have increased, Circa's manufacturing philosophy remains the same: its process will work with as many cellulose-based feedstocks as possible (e.g. sawdust, bagasse, straw, etc.), it will not consume water, it will be almost energy-neutral, and it will avoid intractable waste. Sustainability remains central for Circa and the company continues to work on making its processes as efficient as possible as it begins to focus on FC6, a larger commercial-scale plant.
The positive market feedback on Cyrene's performance over the last year has provided the foundation Circa and its partners needed to move forward with feasibility studies for FC6. Safer solvents are urgently required and Circa is committed to continue creating non-toxic, high-performance chemicals from non-food biomass for advanced materials.