N‐Acetyl p‐toluidine (I) reacts with acetic anhydride (II) in the presence of polyphosphoric acid to produce the isomeric acetaminoacetophenones (III) and (IV).

The size dependent colloidal behavior of aqueous dispersions of carboxylated multiwall carbon nanotubes (c-MWCNTs) is presented. The presence of carboxylic groups provided electrostatic stabilization in water, where the size affected agglomeration. While aspect ratio did not show any definite correlation, the hydrophobicity indices (HI), zeta potential and aggregation kinetics showed dependence on the length of the c-MWCNTs where the shorter c-MWCNTs showed significantly lower HI values, smaller particle aggregates, higher zeta potential values and higher critical coagulation concentrations (ccc) in the presence of electrolytes. Although the diameter of the short c-MWCNTs did not appear to influence their aggregation behavior, the longer c-MWCNTs showed a dependence on diameter where stability decreased with increasing CNT diameter.

A comparative study between detonation nanodiamonds (DNDs) and carbon nanotubes (CNTs) as low concentration additives to epoxy composites is presented. The dispersibility of the different nanocarbons in resin solutions leading to uniform composite formation is also discussed. Significant increase in glass transition temperature was observed, which were 37 °C and 17 °C for DNDs and CNTs, respectively. Unlike the pure epoxy, the fractured surface of both composites showed resistance to crack propagation. Tensile properties of DNDs and CNTs composites showed enhancement of 6.4% and 2.9%, respectively. The nanocomposites also showed an increase in microhardness by 41% for DNDs and 12% for CNTs, and a decrease in electrical resistivity by 2 orders of magnitude, with the CNTs showing lower resistivity. In general, the DNDs were found to be quite effective and at the reported concentrations between 0.1% and 0.5% and showed superior enhancement compared to the CNTs.

The colloidal behavior of aqueous dispersions of detonation nanodiamonds (DNDs) and carboxylated nanodiamonds (DND-COOH) which were synthesized via a microwave process is presented. Both forms of DNDs were found to be relatively stable in aqueous solutions, but aggregated rapidly in the presence of mono and divalent salts. The critical coagulation concentration (CCC) values for DNDs and DND-COOH were estimated to be between 8 and 10 mM for NaCl and 7 and 8 mM for MgCl2. In general, the formation of carboxyl groups on the DND surface did not alter colloidal behavior as dramatically as it is known to do for other nanocarbons especially carbon nanotubes.

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