The 600 mL high-pressure reactor enables controlled investigation of liquid-phase transformations under elevated temperature and gas pressure. It supports studies up to about 200 bar and 350 °C, making it suitable for lignin depolymerization, catalytic hydrogenolysis, and solvent-mediated biomass upgrading. The robust vessel design accommodates reactive gases such as H₂ or O₂, while electronic control of heating and cooling ensures stable reaction conditions. Feed introduction ports allow staged reagent addition for kinetic or mechanistic studies. This system provides a versatile platform for biomass valorization, homogeneous and heterogeneous catalysis, polymer degradation, and broader process-development research.