Hydrodeoxygenation of anisole – influence of reaction time on reactivity of SBA-16 catalyst containing Pt or Pd atoms
Paulina Szczyglewska, Agnieszka Feliczak-Guzik and Izabela Nowak
Faculty of Chemistry, Adam Mickiewicz University in Poznań, Umultowska 89b, 61-614, Poznań, POL
Biomass due to its renewable nature, high availability and non toxic character is considered as an alternative energy source in the context of fossil fuels1. For this purpose, above mentioned biomaterial is transformed to bio-oil, which consists of many organic aromatic compounds containing in their structure oxygen atoms. For this reason, bio-oil is characterized by poor chemical stability and immiscibility with hydrocarbon fuels and therefore cannot be directly used as a transportation fuel2.
Catalytic hydrodeoxygenation (HDO) is one of the most viable processes for converting bio-oil into biofuels because it can reduce the O/C ratio and increase the H/C ratio significantly. This process was carried out at high temperatures and hydrogen pressure and in the presence of suitable catalyst3. The type of used catalytic systems has a key role in the whole process. According to the literature, catalysts based on noble metals (Rh, Ru, Pt, Pd) exhibit high activity in the HDO reaction. Materials with a porous structure and large surface area, i.e. ordered mesoporous silica of SBA-16 type are used as carriers4.
In the study on the HDO of bio-oil, model compounds that have similar properties to bio-oil, such as phenol, anisole, guaiacol were used instead of real bio-oil. Anisole is typically used in the HDO process as a model compound because it contain methoxy (-OCH3) group which is most typical for lignin-derived phenolic monomers.
Our studies were focused on the application of SBA-16 materials modified with platinum or palladium species as catalysts in HDO reaction of anisole and investigating the influence of reaction time on the final results.
The HDO activity of the catalyst (SBA-16/Pt and SBA-16/Pd) in the HDO process of anisole was performed in a high-pressure reactor at 110°C and hydrogen pressure equal to 60 bar. The reaction was carried for different periods: 1, 2.5 or 4h. The gas products were analyzed by gas chromatography.
Our work demonstrated that Pt an Pd-containing nanocatalysts are efficient for the HDO of anisole. These catalysts are highly selective to methoxycyclohexane (lower O/C ratio). SBA-16/Pd catalyst is characterized by higher catalytic activity than SBA-16/Pt catalyst. Additionally, the catalytic activity of both catalysts increased with the time extension of reaction.
National Science Centre is kindly acknowledged for the financial support (project no: DEC-2013/10/M/ST5/00652).