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1.
Churruca F SanMartin R Carril M Urtiaga MK Solans X Tellitu I Domínguez E 《The Journal of organic chemistry》2005,70(8):3178-3187
Novel dibenzo[a,c]phenanthridines are prepared regioselectively by the application of a straightforward synthetic pathway, starting from new 3,4-diaryl- and 3,4-dihydro-3,4-diarylisoquinolines prepared via Ritter-type heterocyclization and the more classical two-step reductive amination/Bischler-Napieralski cyclization of triarylethanones, respectively. A comparative study of nonphenolic oxidative coupling methodologies provides a highly efficient procedure, based on the hypervalent iodine reagent phenyliodine(III) bis(trifluoroacetate) (PIFA), to accomplish the final coupling step. 相似文献
2.
Monika Goikoetxea Roque J. Minari Itxaso Beristain María Paulis María J. Barandiaran José M. Asua 《Journal of polymer science. Part A, Polymer chemistry》2009,47(19):4871-4885
Waterborne acrylic‐alkyd nanocomposites are expected to combine the positive properties of alkyd resins and acrylic polymers. In this work, the kinetics of the miniemulsion polymerization used to synthesize these nanocomposites and the effect of the process variables on the polymer architecture and particle morphology was investigated. It was found that resin hydrophobicity and the type of initiator strongly affected the microstructure of these materials. The mechanisms responsible for these effects were discussed. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 4871–4885, 2009 相似文献
3.
Jos M. Arandes Javier Erea Miren J. Azkoiti Martin Olazar Javier Bilbao 《Journal of Analytical and Applied Pyrolysis》2003,70(2):975-760
A study has been made of the cracking on a mesoporous silica of polystyrene (PS) and polystyrene-butadiene (PS-BD) dissolved in a light cycle oil (LCO) from a product stream of a commercial fluid catalytic cracking (FCC) unit. This study has been carried out in a reactor of short contact time (3 s) in the 723–823 K range. This strategy for simultaneous valorization of plastics and solvent avoids the technological problems inherent to the treatment of solid postconsumer-plastics and the limitation to heat transfer in the process of pyrolysis. The cracking of plastics has a synergistic effect on the conversion of LCO, as it contributes to increasing the yield of gasoline (C5–C12). The cracking of the PS/LCO blend produces high yields of styrene, whereas the cracking of the PS-BD/LCO blend produces a stream of products with petrochemical interest. 相似文献
4.
The use of proton nuclear magnetic resonance (1H-NMR) for the quantitation of additives in a commercial electrolytic nickel bath (Supreme Plus Brilliant, Atotech formulation)
is reported. A simple and quick method is described that needs only the separation of nickel ions by precipitation with NaOH.
The four additives in the bath (A-5(2X), leveler; Supreme Plus Brightener (SPB); SA-1, leveler; NPA, wetting agent; all of
them are commercial names from Atotech) can be quantified, whereas no other analytical methods have been found in the literature
for SA-1 and NPA. Two calibration methods have been tried: integration of NMR signals with the use of a proper internal standard
and partial least squares regression applied to the characteristic NMR peaks. The multivariate method was preferred because
of accuracy and precision. Multivariate limits of detection of about 4 mL L−1 A-5(2X), 0.4 mL L−1 SPB, 0.2 mL L−1 SA-1 and 0.6 mL L−1 NPA were found. The dynamic ranges are suitable to follow the concentration of additives in the bath along electrodeposition.
1H-NMR spectra provide evidence for SPB and SA-1 consumption (A-5(2X) and NPA keep unchanged along the process) and the growth
of some products from SA-1 degradation can be followed. The method can, probably, be extended to other electrolytic nickel
baths. 相似文献
5.
Torre-Fdez Imanol Aramendia Julene Gomez-Nubla Leticia Castro Kepa Maguregui Maite Fdez-Ortiz de Vallejuelo Silvia Arana Gorka Madariaga Juan M. 《Analytical and bioanalytical chemistry》2018,410(28):7477-7488
Analytical and Bioanalytical Chemistry - The application of a non-destructive analytical procedure to characterise the mineral phases in meteorites is a key issue in order to preserve this type of... 相似文献
6.
Analytical diagnosis methodology to evaluate nitrate impact on historical building materials 总被引:1,自引:0,他引:1
Maguregui M Sarmiento A Martínez-Arkarazo I Angulo M Castro K Arana G Etxebarria N Madariaga JM 《Analytical and bioanalytical chemistry》2008,391(4):1361-1370
Nitrate salts have become of greater importance in the decay of materials from historical buildings due to changes in the
environment. This work presents an analytical diagnosis methodology to evaluate the impact of nitrate salts in mortars and
bricks, combining noninvasive and microdestructive analytical techniques together with chemometric and thermodynamic data
analyses. The impact of nitrate salts cannot be well ascertained if other soluble salts are not taken into account. Therefore,
the principal results from this work relate to nitrate salts but some results for other kinds of salts are included. Data
from Raman microprobe spectroscopy and micro X-ray fluorescence (μ-XRF) are used to characterise the original composition
and a first approximation of the nature of the decay compounds, mainly nitrates. The soluble salts are extracted and the anions
and cations are quantified by means of ion chromatography with conductimetric detection for anions/cations and inductively
coupled plasma mass spectrometry (ICP/MS) for cations. The values obtained allow two different data treatments to be applied.
First, chemometric analysis is carried out to search for correlations among anions and cations. Second, thermodynamic modelling
with the RUNSALT program is performed to search for environmental conditions of soluble salt formation. All the results are
finally used to diagnose the impact of nitrates. 相似文献
7.
M. Maguregui A. Sarmiento R. Escribano I. Martinez-Arkarazo K. Castro J. M. Madariaga 《Analytical and bioanalytical chemistry》2009,395(7):2119-2129
Bricks, together with stones and mortars, can be considered as one of the most important building materials that constitute
our built heritage. Numerous factors which cause several decaying pathologies in bricks can be listed, but it should be emphasised
that the most severe and damaging one is the wet and dry deposition of both combustion and greenhouse gases (CO2, SO
x
and NO
x
mainly). For instance, after the impact of CO2 and SO
x
, the decayed products promoted in bricks are carbonates and sulphates. Once identified in all these kinds of salts in real
samples, it is necessary to make sure that the aggressive atmospheric conditions are sufficient to promote the formation of
these salts. Therefore, accelerated exposure test are a good alternative in order to simulate the formation of these decayed
compounds and to predict the reactions that promote the decaying mechanism. In this work, brick samples manufactured at different
firing temperatures following ancient methods were subjected to humidity/dryness, freeze/thaw, CO2 and SO2 (KESTERNICH DIN 50018) accelerated ageing tests followed by a Raman spectroscopy screening in order to verify the formation
of sulphate and carbonate salts in bricks on accelerated conditions, simulating the damage caused by a polluted atmosphere
throughout many years of exposure.
相似文献
8.
We study the forward problem of the magnetic Schrödinger operator with potentials that have a strong singularity at the origin. We obtain new resolvent estimates and give some applications on the spectral measure and on the solutions of the associated evolution problem. 相似文献
9.
Ainara Barriola José I. Miranda Miren Ostra Carlos Ubide 《Analytical and bioanalytical chemistry》2010,398(2):1085-1094
The use of proton nuclear magnetic resonance (1H-NMR) for the quantification of additives in an electrolytic Zn bath is reported. A simple and quick method is described
that does not need any prior sample preparation. Contrary to other analytical methods, the three additives in the bath, benzylidene
acetone (BDA), benzoic acid (BA) and poly(ethylene glycol) (PE400), can be quantified. Two calibration methods were tried:
integration of NMR signals with the use of an internal standard and partial least squares (PLS) regression applied to the
characteristic NMR peaks. Both methods are compared and the univariate method was preferred because of simplicity, accuracy
and precision. The following limits of detection were found: 0.30 g L−1 BA, 0.08 g L−1 BDA and 0.7 g L−1 PE400 with dynamic ranges of at least 1.0–6.0, 0.1–0.6 and 3.0–18.0 g L−1 respectively. Those concentration ranges are suitable to follow the concentration of additives in the bath in real time.
1H-NMR spectra provide evidence for the BDA degradation pattern. 相似文献
10.
I. Martínez-Arkarazo A. Sarmiento M. Maguregui K. Castro J. M. Madariaga 《Analytical and bioanalytical chemistry》2010,397(7):2717-2725
Any restoration performed on cultural heritage artworks must guarantee a low impact on the treated surfaces. Although completely
risk-free methods do not exist, the use of tailor-made procedures and the continuous monitoring by portable instrumentation
is surely one of the best approaches to conduct a modern restoration process. In this work, a portable Raman monitoring, combined
sometimes with spectroscopic techniques providing the elemental composition, is the key analysis technique in the three-step
restoration protocol proposed: (a) in situ analysis of the surface to be treated (original composition and degradation products/pollutants)
and the cleaning agents used as extractants, (b) the thermodynamic study of the species involved in the treatment in order
to design a suitable restoration method and (c) application and monitoring of the treatment. Two cleaning operations based
on new technologies were studied and applied to two artworks on mineral supports: a wall painting affected by nitrate impact,
and a black crusted stone (chalk) altarpiece. Raman bands of nitrate and gypsum, respectively, decreased after the step-by-step
operations in each case, which helped restorers to decide when the treatment was concluded, thus avoiding any further damage
to the treated surface of the artworks. 相似文献