Evaluation of thermal stability of quinones by thermal analysis techniques

Sousa, Eliane Teixeira; Silva, Mateus Melo da; Andrade, Sônia Gumes; Cardoso, Manuela; Silva, Luciana da; Andrade, Jaílson Bittencourt de

doi:10.1016/j.tca.2011.11.012

Cited by 24 publications

(21 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In the same table, the experiments conducted at 170 • C and 220 • C gave similar total yields. However the mass of AQs in the 220 • C extract was less than half that measured at 170 • C. This may be attributed to a AQs decomposition above 170 • C in accordance with the literature [18,20,34] and considering the difference found in the chromatographic profiles at two temperatures (170 and 220 • C) (data not shown). Furthermore, considering the relative percentages of each anthraquinone in the extracts, 2-hydroxy-3-methyl anthraquinone appears to have the lower thermal stability.…”

Section: Effect Of Temperature On the Extractionsupporting

confidence: 87%

“…However, AQs could decompose at high temperatures. Teixeira Sousa et al [34] studied the thermal behavior of quinones and found that the thermal stability of these compounds is strongly influenced by their molecular structure. These authors found that 9,10-antraquinone starts to decompose above 215 • C. On the other hand, working on the PHWE of Morinda citrifolia roots, Shotipruk et al [18] found alizarin (1,2-dihydroxy anthraquinone) to be stable up to 220 • C, while Anekpankul et al [20] reported the decomposition of damnacanthal (3-hydroxy-1-methoxy anthraquinone-2-aldehyde) above 170 • C.…”

Section: Effect Of Temperature On the Extractionmentioning

confidence: 99%

See 1 more Smart Citation

Pressurized hot water extraction of anthraquinones from Heterophyllaea pustulata Hook f. (Rubiaceae)

Vázquez

Comini

Milanesio

et al. 2015

The Journal of Supercritical Fluids

View full text Add to dashboard Cite

Section: Effect Of Temperature On the Extractionsupporting

confidence: 87%

Section: Effect Of Temperature On the Extractionmentioning

confidence: 99%

Pressurized hot water extraction of anthraquinones from Heterophyllaea pustulata Hook f. (Rubiaceae)

Vázquez

Comini

Milanesio

et al. 2015

The Journal of Supercritical Fluids

View full text Add to dashboard Cite

“…This is based on the thermal instability of 1,2-naphthoquinone. Thermal analysis of quinones revealed that while 1,4-naphthoquinone exhibits thermal stability up to 600 • C, 1,2-naphthoquinone begins decomposing at temperatures higher than 100 • C, and the thermal instability was verified by very poor reproducibility in GC-MS analysis (Sousa et al, 2012). The authors attributed the thermal instability to the carbonyl groups of the quinones being in the ortho position to each other, as 9,10-phenanthrenequinone also exhibited thermal instability.…”

Section: Air-particle Partitioning Of 14-naphthoquinonementioning

confidence: 99%

Naphthalene SOA: redox activity and naphthoquinone gas–particle partitioning

2013

View full text Add to dashboard Cite

Abstract. Chamber secondary organic aerosol (SOA) from low-NO x photooxidation of naphthalene by hydroxyl radical was examined with respect to its redox cycling behaviour using the dithiothreitol (DTT) assay. Naphthalene SOA was highly redox-active, consuming DTT at an average rate of 118 ± 14 pmol per minute per µg of SOA material. Measured particle-phase masses of the major previously identified redox active products, 1,2-and 1,4-naphthoquinone, accounted for only 21 ± 3 % of the observed redox cycling activity. The redox-active 5-hydroxy-1,4-naphthoquinone was identified as a new minor product of naphthalene oxidation, and including this species in redox activity predictions increased the predicted DTT reactivity to 30 ± 5 % of observations. These results suggest that there are substantial unidentified redox-active SOA constituents beyond the small quinones that may be important toxic components of these particles. A gas-to-SOA particle partitioning coefficient was calculated to be (7.0 ± 2.5) × 10 −4 m 3 µg −1 for 1,4-naphthoquinone at 25 • C. This value suggests that under typical warm conditions, 1,4-naphthoquinone is unlikely to contribute strongly to redox behaviour of ambient particles, although further work is needed to determine the potential impact under conditions such as low temperatures where partitioning to the particle is more favourable. Also, higher order oxidation products that likely account for a substantial fraction of the redox cycling capability of the naphthalene SOA are likely to partition much more strongly to the particle phase.

show abstract

“…40,74 Em estudos termogravimétricos recentes foi observado que a 1,4-BQ, 1,4-NQ e 9,10-AQ são termicamente estáveis no intervalo de 25 -600 ºC, enquanto que a 1,2-NQ 74 e a 9,10-FQ 76,77 apresentam estabilidade térmica menor, existindo indicativos de decomposição mais pronunciada a partir de 243 ºC para a 1,2-NQ e a partir de 265 ºC para a 9,10-FQ. 76 Esta menor estabilidade pode ser explicada com base nas interações intermoleculares de grupos carbonila em posição adjacente. 76 Considerando que nos métodos cromatográficos reportados na literatura aberta 10 a 1,2-NQ é detectada por CG-EM quando a temperatura da coluna está em 195 ºC e a 9,10-FQ em 231 ºC, revelando assim a determinação direta destes compostos.…”

Section: Cromatografia Gasosa (Cg)unclassified

“…76 Esta menor estabilidade pode ser explicada com base nas interações intermoleculares de grupos carbonila em posição adjacente. 76 Considerando que nos métodos cromatográficos reportados na literatura aberta 10 a 1,2-NQ é detectada por CG-EM quando a temperatura da coluna está em 195 ºC e a 9,10-FQ em 231 ºC, revelando assim a determinação direta destes compostos. 40,74 Outras técnicas, ainda não utilizadas na determinação de quinonas, poderão melhorar a etapa de preparação bem como a sensibilidade.…”

Section: Cromatografia Gasosa (Cg)unclassified