Jacopo Ceccarelli

Formaldehyde (FA) is a toxic compound and a human carcinogen. Regulating FA-releasing substances in commercial goods is a growing and interesting topic: worldwide production sectors, like food industries, textiles, wood manufacture, and cosmetics, are involved. Thus, there is a need for sensitive, economical, and specific FA monitoring tools. Solid-phase microextraction (SPME), with O-(2,3,4,5,6-pentafluorobenzyl)-hydroxylamine (PFBHA) on-sample derivatization and gas chromatography, is proposed for FA monitoring of real-life samples. This study reports the use of polydimethylsiloxane (PDMS) as a sorbent phase combined with innovative commercial methods, such as multiple SPME (MSPME) and cooling-assisted SPME, for FA determination. Critical steps, such as extraction and sampling, were evaluated in method development. The derivatization was performed at 60 °C for 30 min, followed by 15 min sampling at 10 °C, in three cycles (SPME Arrow) or six cycles (SPME). The sensitivity was satisfactory for the method’s purposes (LOD-LOQ at 11-36 ng L⁻¹, and 8-26 ng L⁻¹, for SPME and SPME Arrow, respectively). The method’s linearity ranges from the lower LOQ at trace level (ng L⁻¹) to the upper LOQ at 40 mg L⁻¹. The precision range was 5.7–10.2% and 4.8–9.6% and the accuracy was 97.4% and 96.3% for SPME and SPME Arrow, respectively. The cooling MSPME set-up applied to real commercial goods provided results of quality comparable to previously published data.

The reduction of aromatic nitro compounds has been performed employing a catalytic amount of Wang resin-supported phenyl(2-quinolyl)methanol (Wang-PQM) in the presence of an excess of NaBH₄ to regenerate the reactive reducing species at the end of the process. The reduction products are easily isolated through a simple filtration/extraction protocol, and the catalyst can be efficiently recovered and recycled. The condensation route is generally preferred, and azo- and/or hydrazo-arenes can be easily prepared in high yields.

Glycerol, a by-product of biodiesel production, can be efficiently converted into α-monobromohydrin or α,γ-dibromohydrin with trimethylsilyl bromide (TMSBr), in solvent-free and mild reaction conditions.

Phenyl (2‐quinolyl) methanol (PQM) behaves as a new efficient reagent for metal‐free reduction of nitro aromatic and heteroaromatic compounds. The reduction proceeds in mild reaction conditions affording anilines in good yields. Phenyl (2‐quinolyl) ketone (PQK), the oxidation product of PQM, can be quantitatively recovered and reused after reduction making sustainable the overall process. The reduction outcome changes with electron‐deficient nitroarenes that afford the expected anilines and electron‐rich nitro compounds that give reductive amination products via reduction of imines formed by condensation of nucleophilic anilines with PQK. These multicomponent reactions were observed also with activated aldehydes and in the presence of acrylates for the synthesis of β‐anilino esters. The synthetic value of the new metal‐free reducing agent, unmatched by the well‐known Hantzsch ester, has been exploited in metal‐free Reissert indole and Friedländer quinoline syntheses.