Temperature effects upon aqueous micellar-assisted decarboxylation of 6-nitrobenzisoxazole-3-carboxylate and its 5-methyl derivative.
An investigation of temperature effects upon first-order rate constants in the micellar pseudophase for decarboxylation of 6-nitrobenzisoxazole-3-carboxylate (6-NBIC) and its 5-methyl derivative (6-NBIC-5-Me) was carried out. Surfactants used were cationic cetyltrialkylammonium bromide with alkyl = methyl (CTABr), ethyl (CTEABr), n-propyl (CTPABr), and n-butyl (CTBABr). The investigation shows that micelles speed up reactions by decreasing enthalpies of activation. Increase in head group bulk further speeds reactions still by a small decrease in the enthalpies, for both substrates. Values of DeltaH# and DeltaS# for 6-NBIC in the various surfactants give linear isokinetic plot, with CTBABr as outlier.
Catalysis by surfactant aggregates in aqueous solutions
Abstract
12.2: Enhanced Electron Emission of the Cone‐Shaped Emitters with Carbon Nanostructures
We developed novel cone‐shaped emitters with individual carbon nanotips using the resist‐assisted patterning process. The novel cone‐shaped nanotip emitters were arranged in an array with many nano emitters in pre‐patterned diameters of 3 μm. The cone‐shaped nanotip emitters consist of a number of carbon‐based nanostructures such as nanotubes and/or nanofibers with silicon and nitrogen elements at the periphery of each element. The cone‐shaped nano‐emitters strongly adhered to the substrate due to the large area bottom contact which is covered with diffused silicon elements. The growth mechanism and enhanced electron emission of cone‐shaped nanotip emitters was discussed.