Professor Je Jeongho's Team from the Department of Applied Chemical Engineering Publishes in Journal
Reaction Efficiency Increases Over Fivefold with Supercritical Carbon Dioxide Injection
Potential Industrial Applications in Pharmaceuticals, Cosmetics, and Chemical Products
A new pathway has opened to utilize 'cellulose,' a carbon-neutral plant-based resource, as a high-value-added chemical feedstock instead of conventional petroleum resources.
Pusan National University (President Choi Jaewon) announced on the 3rd that Professor Je Jung Ho’s research team from the School of Applied Chemical Engineering has successfully developed an eco-friendly reaction process that can efficiently convert the natural substance 'cellulose' into polyhydric alcohols.
Polyhydric alcohols are compounds containing two or more alcoholic hydroxyl groups (-OH) within their molecules and are used in various fields such as food, pharmaceuticals, and industry.
‘Cellulose’ is a major component of plant resources such as wood and grass and is an abundantly available natural substance on Earth. Recently, to achieve carbon neutrality in response to climate change, there has been significant research into using eco-friendly carbon sources like cellulose instead of petroleum resources to produce plastic monomers and sustainable chemicals.
Cellulose is a natural polymer in which hundreds to thousands of polyhydric alcohols, such as glucose, are linked together. If these bonds are selectively cleaved, cellulose can be converted into basic chemical substances such as polyhydric alcohols (e.g., ethylene glycol, sucrose), which are widely used industrially. However, due to its strong crystalline structure formed by hydrogen bonding, cellulose is typically decomposed using non-eco-friendly methods involving high concentrations of sulfuric acid.
To overcome this, water-based reaction systems using solid acid catalysts such as activated carbon with introduced functional groups have been developed. However, the contact between solid cellulose and solid catalysts is limited, resulting in significantly lower reaction efficiency and speed.
In this study, the researchers introduced supercritical carbon dioxide into the conventional solid acid catalyst process, adding both the acid-catalyst effect from carbonic acid and the effect as a reaction solvent. This successfully increased the reaction efficiency by more than five times compared to existing processes.
Supercritical refers to a state beyond the critical point, where the distinction between liquid and gas disappears at a certain temperature and pressure. Supercritical fluids possess properties of both liquids and gases, with density similar to liquids and viscosity similar to gases. Due to these characteristics, they are used in various industries for applications such as solvents, extraction, and cleaning.
Professor Je Jung Ho’s team, in collaboration with researchers from Sungkyunkwan University, demonstrated through real-time reactor monitoring that catalyst particles adsorb at the interface between water and supercritical carbon dioxide, forming emulsion droplets, and that hydrophilic cellulose is trapped within the aqueous phase inside these emulsion droplets.
Kinetics experiments revealed that the confined space of these nanodroplets reduces the entropy (degree of disorder) of cellulose molecules and enhances the contact efficiency (diffusion rate) between the solid catalyst and cellulose molecules, resulting in a dramatic increase in reaction efficiency at the molecular level.
In addition to high reaction efficiency, the process is environmentally friendly because, after the reaction, carbon dioxide is recovered as a gas through pressure reduction and spontaneously separates from the product, eliminating issues such as acid-base neutralization or solvent separation found in conventional processes.
Recently, using carbon-neutral plant-based resources as chemical feedstocks instead of traditional petroleum resources has become a global issue for achieving Net-Zero (net-zero greenhouse gas emissions) and carbon neutrality. In particular, chemical reactions that produce polyhydric alcohols with wide industrial applications, such as pharmaceuticals, cosmetics, and chemical products, from cellulose are expected to have significant industrial utility.
This research was conducted with support from the Mid-career Researcher Support Program, Basic Research Laboratory Program, and Climate Change Response Technology Development Program of the Ministry of Science and ICT and the National Research Foundation of Korea. Professor Je Jung Ho of Pusan National University served as the corresponding author, Dr. Kim Hanwoong as the first author, and researchers from Sungkyunkwan University, University of Seoul, and Korea Institute of Industrial Technology participated. The study was published in the August 1 issue of the international journal 'Chemical Engineering Journal.'
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