(680g) Understanding and Improving the Synthesis of Starbon® Materials from Low Amylose Content Starches for Its Use As Catalyst

Starbons® are bioderived porous materials produced by the controlled pyrolysis of polysaccharides. These have high porosity, large surface areas and the ability of adsorbing a wide range of molecules. According to the carbonization temperature, the hydrophilic-hydrophobic character of their surface, and their stability changes, having applications in catalysis, separation processes, and energy storage. Conventionally, Starbons® are produced using a high-amylose-content starch (Hylon®VII) which guarantees a high mesopore volume due to the arrangement of amylose molecules during the synthesis.

Looking for valorizing waste streams, and using second generation raw materials, the exploitation of waste starches is of interest for industrial applications. Particularly, these are produced in high volumes during the transformation of potato and cassava in the stacks industry, their manufacture, and the whole supply chain. According to Colombian National Planning Department, nearly 5 million ton of roots and tubers are produced in Colombia, nevertheless, almost 30% are discarded because of quality standards. Such materials could be valorized extracting starches and transforming them into value-added products such as biobased catalysts.

In this regard, this work focused on understanding and optimizing Starbon® materials obtention from low-amylose-starches, such as potato and cassava. The synthesis involves a sol-gel-method in which the conditions for the gelatinization, retrogradation, solvent exchange and carbonization were assessed. Therefore, synthesis parameters were defined for getting higher mesoporosity and surface areas in the low-amylose-starch-derived Starbons®. The obtained materials were characterized by nitrogen sorption, exhibiting a surface area of around 250 m²/g, average pore width between 8 nm and 10 nm, and mesoporous fraction of approximately 80%. These properties allow its used as supporting structures for heterogeneous catalysts in reactions which involve large molecules. As a validation, the material was sulfonated and evaluated as catalyst in the esterification of stearic acid with 2-propanol, showing a better performance than typically used ion-exchange resins.