Catalysis 2026 Issue

Circular aromatics by breakthrough technological synergies

Smart catalyst design and cascading pyrolysis processes deliver record BTX yields from waste plastics and biomass sources

Danny Verboekend, Judy El Jablaoui, and Kurt Du Mong Zeopore Technologies NV Diana Ciolca and Niels J. Schenk BioBTX B.V.

C hemicals are the building blocks for the plethora of carbon-containing products that cater to our modern way of life. However, the chemical industry uses siz- able amounts of fossil carbon that will, at a certain moment in the life cycle, end up in the environment as CO₂. This forms a large societal problem, causing losses in biodiver- sity and adverse health effects.¹ These hazards call for the adoption of technologies that accelerate the transition to sustainable chemical building blocks and promote the cir- cularity of plastics. There are only seven chemical building blocks from which more than 95% of all materials are made: methanol, ethylene, propylene, butene, benzene, toluene, and xylene. Chemical recycling has shown to be an essential tech- nology in maximising the circularity of plastics. 2 The core component of chemical recycling involves breaking down large polymer chains into smaller fractions, ideally back to the original monomers, typically using heat and an inert atmosphere (i.e., pyrolysis). Catalysts can be contacted with waste plastic and combined with pyrolysis in several different ways, either by directly contacting the waste plas- tics with the catalysts or by integrated upgrading of the pyrolysis vapours. Combining synergistic technologies In order to address the abundance of challenges common to waste plastic feedstocks catalysis, BioBTX developed the proprietary Integrated Cascading Catalytic Pyrolysis (ICCP) technology to convert biomass and plastic waste into ben- zene, toluene, and xylene (BTX) aromatics. The cascading design separates the pyrolysis and catalytic stages, allow- ing protection against contaminants and higher control over reaction conditions. Ultimately, this achieves a higher BTX yield and purity.3 As in an established oil refinery and the adjacent chemi - cal industry, zeolite catalysts hold the potential to become the workhorse of the plastic waste refinery, for example, in cracking reactions. Proprietary mesoporisation tech- nologies are able to optimise the conversion efficiency of any zeolite catalyst on the market today. The introduction of mesoporosity in zeolite catalysts has proven to be the key to yielding superior performance in virtually any cata- lytic reaction, including the chemical conversion of waste

plastics.4 Against this backdrop, it raises the question: what is the impact of the application of Zeopore technology in the BioBTX process? In this contribution, an unprecedented performance boost was demonstrated based on the synergy between advanced pyrolysis processes and tailored catalyst design. Polyolefinic and biomass waste streams are exposed to the ICCP process, in which the resulting pyrolysis vapours are converted to aromatics via metal-based aromatisation catalysts. By strategically implementing aromatisation cat- alysts at different scales in the pyrolysis process and by tuning both the accessibility and the nature of the metal site in the catalysts, unique yields of circular aromatics are achieved at a significantly reduced footprint. The introduction of mesoporosity in zeolite catalysts is the key to yielding superior performance in virtually any catalytic reaction Catalytic pyrolysis picture Perhaps the most intuitive way to achieve catalytic pyrol- ysis is to simply mix (zeolite-based) catalysts with waste plastics and let them react at increased temperature. The advantage of this type of catalytic pyrolysis is that the cat- alytic active sites are in closest possible proximity to the plastic polymer waste substrate to be converted. This may help lower the temperature needed to enable the cracking of the bonds to occur and provides the largest potential to boost selectivity towards the desired liquid fraction. The reality, however, is that the streams of waste plastics contain such a wide variety of contaminants that any direct contact with a catalyst will deactivate it almost instantane- ously. Accordingly, either the catalyst is deemed to work in a sacrificial manner, or the plastic waste stream will need to be separated to a rather high degree to achieve less diverse streams. Given these practical complexities, other catalytic pyro- lytic configurations have been devised, based on upgrading either the oil coming the pyrolysis process or the vapours

Catalysis 2026