13 research outputs found
Simple and rapid hydrogenation of p-nitrophenol with aqueous formic acid in catalytic flow reactors
The inner surface of a metallic tube (i.d. 0.5 mm) was coated with a palladium (Pd)-based thin metallic layer by flow electroless plating. Simultaneous plating of Pd and silver (Ag) from their electroless-plating solution produced a mixed distributed bimetallic layer. Preferential acid leaching of Ag from the Pd–Ag layer produced a porous Pd surface. Hydrogenation of p-nitrophenol was examined in the presence of formic acid simply by passing the reaction solution through the catalytic tubular reactors. p-Aminophenol was the sole product of hydrogenation. No side reaction occurred. Reaction conversion with respect to p-nitrophenol was dependent on the catalyst layer type, the temperature, pH, amount of formic acid, and the residence time. A porous and oxidized Pd (PdO) surface gave the best reaction conversion among the catalytic reactors examined. p-Nitrophenol was converted quantitatively to p-aminophenol within 15 s of residence time in the porous PdO reactor at 40 °C. Evolution of carbon dioxide (CO2) was observed during the reaction, although hydrogen (H2) was not found in the gas phase. Dehydrogenation of formic acid did not occur to any practical degree in the absence of p-nitrophenol. Consequently, the nitro group was reduced via hydrogen transfer from formic acid to p-nitrophenol and not by hydrogen generated by dehydrogenation of formic acid
Chromatographic Selectivity of Rare Earth Elements on Iminodiacetate-Type Chelating Resins Having Spacer Arms of Different Lengths: Importance of Steric Flexibility of Functional Group in a Polymer Chelating Resin
Ion Chromatographic Separation of Rare-Earth Elements Using a Nitrilotriacetate-Type Chelating Resin as the Stationary Phase
Continuous Dehydrogenation of Aqueous Formic Acid under Sub-Critical Conditions by Use of Hollow Tubular Reactor Coated with Thin Palladium Oxide Layer
METAL PHOSPHATE (M=Zr, Ce) COMPOSITE MATERIALS FOR THE SEPARATION, CONCENTRATION AND DETECTION OF TRACE Pb (II) IN WATER.
Structural and Electrical Characterization of Carbon Nanofibers for Interconnect Via Applications
We present temperature-dependent electrical characteristics of vertically aligned carbon nanofiber (CNF) arrays for on-chip interconnect applications. The study consists of three parts. First, the electron transport mechanisms in these structures are investigated using I-V measurements over a broad temperature range (4.4 K to 350 K). The measured resistivity in CNF arrays is modeled based on known graphite two-dimensional hopping electron conduction mechanism. The model is used because of the disordered graphite structure observed during high-resolution scanning transmission electron microscopy (STEM) of the CNF and CNF-metal interface. Second, electrical reliability measurements are performed at different temperatures to demonstrate the robust nature of CNFs for interconnect applications. Finally, some guidance in catalyst material selection is presented to improve the nanostructure of CNFs, making the morphology similar to multiwall nanotubes
Removal of As(III) and As(V) by a Porous Spherical Resin Loaded with Monoclinic Hydrous Zirconium Oxide
Image Formation Mechanisms in Scanning Electron Microscopy of Carbon Nanofibers on Substrate
Single-Mode Microwave Reactor Used for Continuous Flow Reactions under Elevated Pressure
We
present a flow type single-mode microwave (MW) reactor that
forms a uniform electromagnetic field along a tubular reactor (quartz
glass, i.d. 1.5 mm × 100 mm) located in the center of a cylindrical
MW cavity. The temperature of liquid flow in the reactor tube was
controlled precisely by a resonance frequency autotracking function.
This MW reactor system is useful for rapid heating of liquid flow
at pressures up to 10 MPa. Continuous flows of polar solvents including
water, ethylene glycol, and ethanol were heated instantaneously beyond
their boiling points by application of pressure. Acceleration of the
reaction was exemplified in continuous synthesis of Cu nanoparticles
by elevation of the reaction temperature beyond the boiling point
of solvent (ethylene glycol) at 2 MPa