Multivariate curve resolution analysis applied to time-resolved synchrotron X-ray Absorption Spectroscopy monitoring of the activation of copper alumina catalyst

Cassinelli, Wellington H.; Martins, Leandro; Passos, Aline Ribeiro; Pulcinelli, Sandra Helena; Santilli, Celso Valentim; Rochet, Amélie; Briois, Valérie

doi:10.1016/j.cattod.2013.10.077

Cited by 112 publications

(109 citation statements)

References 36 publications

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“…[29] In the present case, the decrease of the white line intensity of the Quick-XANESs pectra, together with the presence of ap eak at 8981.2 eV in the first derivative, were in line with the formation of this monovalentc opper-based species. The presence of such an intermediate oxidic Cu…”

Section: Operando Xas Copper Speciationmentioning

confidence: 59%

“…The Cu 2 + , Cu + ,and Cu 0 species involved in the activation process of the catalysts were determined using amultivariate curve resolution with alternating least squares (MCR-ALS) chemometric method, as discussed previously. [29] The X-ray absorption near edge structure spectrum (XANES) of the Cu 2 + component determined by MCR-ALS was similar to that of the catalyst recorded at 50 8Cp rior to activation, whereas the spectrum of the MCR-ALS Cu 0 component was characteristic of metallic copper nanoparticles, and similar to the experimental XANES spectrum recorded for the 10 Cu/Al catalyst at the end of the ethanol dehydrogenation reaction. The LCF procedure for resolving copper speciation during the activation of xCu/Al employed the experimental XANES data characteristic of the Cu 2 + and Cu 0 components, together with the XANES spectrum determined by MCR-ALS for the Cu + component.…”

Section: Characterization Of the Catalystsmentioning

confidence: 70%

“…The XANES spectrum of this intermediate speciesd etermined by MCR-ALS [29] was therefore included as at hirdc omponent forl inear combination fittingo ft he experimental XANES spectra measured during reduction of the catalysts.…”

Section: Operando Xas Copper Speciationmentioning

confidence: 99%

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Correlation between Structural and Catalytic Properties of Copper Supported on Porous Alumina for the Ethanol Dehydrogenation Reaction

et al. 2015

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Carbon nanofibers (CNFs) were functionalized with aryl sulfonic acid groups using in situ diazonium coupling. The use of diazonium coupling yielded an acidic carbon material, in which the introduced acidic groups are readily accessible to the triglyceride substrate. The material is an efficient catalyst for the transesterification of triolein and methanol, outperforming conventional sulfonated carbons in both stability and activity per acid site. Upon comparing CNFs with varying degrees of functionalization, a linear correlation between sulfonic acid sites and catalytic performance was found.

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Section: Operando Xas Copper Speciationmentioning

confidence: 59%

Section: Characterization Of the Catalystsmentioning

confidence: 70%

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Correlation between Structural and Catalytic Properties of Copper Supported on Porous Alumina for the Ethanol Dehydrogenation Reaction

et al. 2015

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“…The algorithm for MCR has been reported by many researches. [7][8][9][10][11] MCR can derive the contribution of each component to the spectra through a bilinear model of pure component. Calvo et al 12) studied the effect of temperature on cimetidine crystal transition (forms of A, B, C, D, and mono hydrate) based on attenuated total reflection (ATR)-IR spectroscopy and MCR-ALS.…”

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confidence: 99%

Quantification of Pharmaceutical Compounds Based on Powder X-Ray Diffraction with Chemometrics

Otsuka

Itô

Matsumura

et al. 2016

CHEMICAL & PHARMACEUTICAL BULLETIN

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We propose an approach for the simultaneous determination of multiple components in pharmaceutical mixed powder based on powder X-ray diffraction (PXRD) method coupled with chemometrics. Caffeine anhydrate, acetaminophen and lactose monohydrate were mixed at various ratios. The samples were analyzed by PXRD method in the ranges of 2θ 5.00-30.0 and 35.0-45.0 degrees. Obtained diffractograms were analyzed by conventional peak intensity method, multi curve resolution (MCR)-alternating least squares (ALS) method and partial least squares (PLS) method. Constructed PLS models can most accurately predict the concentrations among different methods used. Each regression vector of PLS correlates not only to the compound of interest but also to the coexisting compounds. The combination of PXRD and PLS methods is concluded to be powerful approach for analyzing multi components in pharmaceutical formulations.Key words powder X-ray diffraction; partial least square; pharmaceutical formulationThe polymorphs and pseudo-polymorphs (hydrates and solvates) of pharmaceuticals exhibit different physicochemical properties such as solubility, dissolution rate, stability and hygroscopicity. These properties strongly relate to the pharmaceutical properties in their dosage forms such as specific bioavailability, efficacy, stability and toxicity.1) Pharmaceutical regulations are, therefore, required for producing appropriate bulk drugs, the crystalline modifications of which (i.e., polymorphism) are well specified or precisely controlled. 2)Powder X-ray diffraction (PXRD) analysis is the most frequently used method for identifying crystalline modifications and for determining their contents in bulk powders.3) Any crystals have their own PXRD patterns. Pharmaceutical formulations are, in general, composed of multiple components including excipients. PXRD is, therefore, useful to identify crystalline compounds in the formulation and to determine their amounts in a non-contact and non-destructive fashion. 4,5) However, PXRD method has large relative errors, typically around ±5%. Such shortcoming of PXRD method is serious when two or more components having broad and overlapping X-ray diffraction peaks are contained in one formulation.Regulatory authorities such as the U.S. Food and Drug Administration and the International Conference on Harmonization have requested to use Process Analytical Technology (PAT) in order to reduce the production risk of inferior pharmaceuticals.6) Since the introduction of guidelines for PAT, online and real-time analysis have increasingly been accepted in pharmaceutical industry as a tool for monitoring and controlling manufacturing process. Non-contact methods, such as PXRD analysis, near infrared (NIR) spectroscopy and terahertz spectroscopy have been paid attention as important tools for PAT. 6) Chemoinformatics are employed by pre-formulation scientists for the quantitative and qualitative analyses of NIR because they can provide ideal means for extracting quantitative information from complex spectra of mult...

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“…Non-negative matrix factorization (NNMF) was used to separate overlapping UV-Vis spectra to identify deactivating species during MTO process over H-SSZ-13 [49]. Multivariate curve resolution (MCR) became very popular across different disciplines for blind source separation and it has been successfully used for XAS [50,51] and IR spectroscopy [52] with kinetic analysis of heterogeneous catalytic reactions with a strong emphasis to simplify the spectral analysis by the conversion of numerous spectra to a few to some component spectra and respective concentration profiles.…”

Section: Multivariate Analysismentioning

confidence: 99%

Trends and advances in Operando methodology

Urakawa

2016

Current Opinion in Chemical Engineering

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After the introduction of the term, operando, the catalysis community has taken significant steps forward to understand chemistry and physics taking place within catalyst body and catalytic reactor on different length and time scales with great motivation to firmly establish catalyst structure vs. catalytic performance relationships. Herein recent advances, current trends and possible future directions in operando methodology are briefly summarized.

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Multivariate curve resolution analysis applied to time-resolved synchrotron X-ray Absorption Spectroscopy monitoring of the activation of copper alumina catalyst

Cited by 112 publications

References 36 publications

Correlation between Structural and Catalytic Properties of Copper Supported on Porous Alumina for the Ethanol Dehydrogenation Reaction

Correlation between Structural and Catalytic Properties of Copper Supported on Porous Alumina for the Ethanol Dehydrogenation Reaction

Quantification of Pharmaceutical Compounds Based on Powder X-Ray Diffraction with Chemometrics

Trends and advances in Operando methodology

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