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1.
J Chem Health Saf ; 29(4): 378-386, 2022 Jun 23.
Artigo em Inglês | MEDLINE | ID: mdl-37207039

RESUMO

Peracetic acid is a disinfection agent used in medical and food processing facilities, and occupational exposures have been documented. To facilitate characterization of daily occupational exposures, the current work describes the development of a personal sampling technique to quantify the peracetic acid concentration in air samples. Peracetic acid atmospheres were generated in 100 L Teflon chambers, and samples were collected on 350 mg XAD-7 solid sorbent tubes for 4 h at a flow rate of 250 mL/min using a personal sampling pump. Indirect measurement of peracetic acid was achieved by desorption from the sorbent and subsequent treatment with cyclohexene to initiate an epoxidation reaction, formally known as the Prilezhaev reaction. The epoxidation product, cyclohexene oxide, was quantified by gas chromatography-mass spectrometry. The reaction enabled quantification of peracetic acid with high specificity over the common co-contaminants hydrogen peroxide and acetic acid, which were introduced in 10-fold and 100-fold excess to challenge the reaction. The technique also demonstrated an overall estimate of bias and precision of 11 and 8%, respectively, and a limit of detection of 60 ppbv was estimated. Preliminary storage experiments indicate that unreacted peracetic acid is stable on the sorbent tubes for 72 h when stored at -20 °C following collection. Overall, the specificity of the reaction and capability to sample for longer time periods than current methods, in addition to the use of safer personal sampling materials, demonstrate the utility of this technique for peracetic acid measurement in air.

2.
Org Lett ; 19(10): 2674-2677, 2017 05 19.
Artigo em Inglês | MEDLINE | ID: mdl-28492330

RESUMO

Synthetic pathways to conjugated macrocycles containing one, two, or three 2,7-bis(2-thienyl)-9H-fluoren-9-one (TFOT) units in the macrocyclic frameworks bearing 10, 16, or 24 aromatic units were developed. The Diels-Alder reaction between (E,E)-1-(5-bromo-2-thienyl)-4-(5-iodo-2-thienyl)-1,3-butadiene and dimethyl acetylenedicarboxylate produced the key Diels-Alder adduct for the subsequent macrocyclic ring formation. UV-vis and fluorescence spectra of the TFOT-containing molecules were recorded, and their electrochemical properties were investigated by cyclic and differential pulse voltammetry. Solvatofluorochromic properties were observed for the TFOT-containing molecules.

3.
Chemistry ; 22(46): 16420-16424, 2016 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-27607838

RESUMO

Synthetic pathways to furan-containing cycloparaphenylenes (CPPs) as molecular nanohoops bearing 10, 12, and 15 aromatic units including furan-2,5-diyl or 2,2'-bifuran-5,5'-diyl units have been developed. The X-ray structures of a partially hydrogenated bifuran-containing CPP precursor and the corresponding fully aromatized bifuran-containing CPP were obtained to allow the determination of their conformational arrangements in the crystal lattice. The optical and electrochemical properties of the furan-containing CPPs were investigated.

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