Showing papers by "Vitaliy L. Budarin published in 2014"

Microwave assisted extraction as an important technology for valorising orange waste

Abstract: Microwave assisted extraction has been demonstrated as an efficient green technology for the recovery of D-limonene from orange waste. Microwave irradiation was shown to be a more efficient method when compared to conventional heating due to its high selectivity for D-limonene, significantly shortened extraction durations and D-limonene yields twice that of conventional heating. Kinetic analysis of the extraction process indicated a typical two-step diffusion process, an initial stage of extraction from the exterior of the cells (1st stage) and diffusion of solute across the membrane (2nd stage). Diffusion coefficients for the initial stage of extraction from the exterior of cells (1st stage) for both conventional and microwave extraction demonstrated similar trends and activation energies. Interestingly, trans-membrane diffusion coefficient for the microwave assisted extraction at 110 °C was significantly high. Crucially, this was not observed with conventional heating suggesting that microwave radiation favourably interacts with the sample during extraction, causing simultaneous cell rupture and diffusion, resulting in greater yield. This provides an important insight into the development of extraction processes for orange peel.

Applications of Nanoparticles in Biomass Conversion to Chemicals and Fuels

Abstract: Biorefineries are facilities that process biomass into fuels, power and value-added chemicals and with the increasing population and depleting petroleum reserves they are fast becoming more important to society. The technology required to process a wide variety of biomass types can be highly complex due to potentially unknown, varying or difficult to breakdown chemical structures within them. One of the prospective routes to a successful biorefinery, that can treat a wide range of biomass and produce products with good selectivity, is the use of nanoparticles as heterogeneous catalysts. The potential of nanoparticles to catalyse and modify chemical processes, thereby influencing both the nature of the products and their distribution is seen as highly promising. In this publication, we aim to give an overview of the use of a range of nano-catalysts and nano-enzymatic supports for greener biorefinery processing. Finally, future prospects of greener routes to nanoparticle production and their integration into biomass are discussed.

Synthesis, Immobilization and Catalytic Activity of a Copper(II) Complex with a Chiral Bis(oxazoline)

Abstract: A chiral bis(oxazoline) bearing CH2OH groups was synthesized from a commercial bis(oxazoline) and characterized by 1H- and 13C-NMR, high resolution ESI-mass spectrometry and FTIR. The corresponding copper(II) complex was immobilized onto the surface of a mesoporous carbonaceous material (Starbon® 700) in which the double bonds had been activated via conventional bromination. The materials were characterized by elemental analysis, ICP-OES, XPS, thermogravimetry and nitrogen adsorption at 77 K. The new copper(II) bis(oxazoline) was tested both in the homogeneous phase and once immobilized onto a carbonaceous support for the kinetic resolution of hydrobenzoin. Both were active, enantioselective and selective in the mono-benzoylation of hydrobenzoin, but better enantioselectivities were obtained in the homogeneous phase. The heterogeneous catalyst could be separated from the reaction media at the end of the reaction and reused in another catalytic cycle, but with loss of product yield and enantioselectivity.