The coupling of catalysis with alternative technologies such as high frequency ultrasound, milling or non-thermal atmospheric plasma. In this scientific strategy, a synergistic effect between catalysis and those alternative technologies, research has been conducted in order to selectively drive a series of elementary reactions to a targeted chemical. One of the main objectives consistent in identification and understanding of physical and chemical phenomena involved, characterization of exited species formed in situ, interaction of those species with organic chemicals and / or catalytic surfaces, their diffusion and stability in a liquid or at the surface of a catalyst, etc. This scientific strategy has allowed us to make advance the state of the art in the selective oxidation of carbohydrates,
Liquid Phase Sonochemical and Sonocatalytic Conversion of Biomass to Chemicals:
During ultrasound irradiation or liquids, cavitation bubbles are generated. These cavitation bubbles can emit light (sonoluminescence) and undergo violent collapse to generate extreme temperatures (> 5000 k), pressures (> 1000 atm) and jet velocities (up to 120 m / s has been reported).
It is these remarkable conditions that allow ultrasound to create unusual physical and chemical properties ideal for degradation of pollutants, synthesis of polymers and nanomaterials. However, to capitalize on these effects, one needs to understand how the physical and chemical properties vary under different solution and sonication conditions such as frequency and power.
Ultrasonic processing has applications in heterogeneous and homogeneous environments, and is able to augment chemical processes through the well-known mechanoacoustic and sonochemical effects from the cavitation bubbles. This can improve radically driven processes, as well as mixing, emulsification and molecular accessibility.
The mechanism and level of enhancement is influenced by the reactor configuration (geometry, transducer type, frequency, flow, power) and the characteristics of the medium (gases present, solid loading, form of the solute, pH etc). Therefore it is of interest to investigate the effect of these parametric variations to further capitalize on the bubble dynamics to enhance the desired ultrasonic effects.
