In-situ 31P MAS NMR probing of the active centers in Ti silicalite molecular sieve

Zhuang, Jing; Han, Xiuwen; Bao, Xinhe

doi:10.1016/j.catcom.2015.01.014

Cited by 3 publications

(3 citation statements)

References 25 publications

(26 reference statements)

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“…Moreover, as the TMP-loaded TS-1 sample was progressively exposed to air at 343 K (Figure B), the intensities of the peaks associated with LA sites (δ 31 P at −32.0 and −34.2 ppm) gradually decrease with the extent of oxygen exposure, meanwhile a new signal at 53.7 ppm emerged, indicating the oxidation of TMP to form TMPO . Similar results were observed when exposing the TMP-loaded TS-1 in urea hydrogen peroxide, which is a well-known oxidizing agent consisting of equal amounts of hydrogen peroxide and urea …”

Section: Applications Of 31p Nmr For Acidity Characterization Of Vari...supporting

confidence: 67%

“…Apart from the presence of the Lewis acidity in conventional aluminosilicate zeolites, titanium silicalites, TS-1, which show prospective applications as efficient catalysts for selective redox reactions under mild conditions, it has been demonstrated that Lewis acid centers in TS-1 zeolites tend to form acid–base adducts with the oxidizing agents, which in turn enhance the electrophilicity of the oxidant to catalyze the oxidation reaction . By means of the 31 P-TMP NMR approach, Bao and co-workers ,− have make intensive efforts in investigating the role of Lewis acidity during oxidation reactions over TS-1 zeolite catalysts. Figure A displays the 31 P MAS spectra of TMP-loaded TS-1 zeolite samples.…”

Section: Applications Of 31p Nmr For Acidity Characterization Of Vari...mentioning

confidence: 99%

“…204 Similar results were observed when exposing the TMP-loaded TS-1 in urea hydrogen peroxide, which is a wellknown oxidizing agent consisting of equal amounts of hydrogen peroxide and urea. 205…”

Section: Chemical Reviewsmentioning

confidence: 99%

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³¹P NMR Chemical Shifts of Phosphorus Probes as Reliable and Practical Acidity Scales for Solid and Liquid Catalysts

2017

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Acid-base catalytic reaction, either in heterogeneous or homogeneous systems, is one of the most important chemical reactions that has provoked a wide variety of industrial catalytic processes for production of chemicals and petrochemicals over the past few decades. In view of the fact that the catalytic performances (e.g., activity, selectivity, and reaction mechanism) of acid-catalyzed reactions over acidic catalysts are mostly dictated by detailed acidic features, viz. type (Brønsted vs Lewis acidity), amount (concentration), strength, and local environments (location) of acid sites, information on and manipulation of their structure-activity correlation are crucial for optimization of catalytic performances as well as innovative design of novel effective catalysts. This review aims to summarize recent developments on acidity characterization of solid and liquid catalysts by means of experimental P nuclear magnetic resonance (NMR) spectroscopy using phosphorus probe molecules such as trialkylphosphine (TMP) and trialkylphosphine oxides (RPO). In particular, correlations between the observed P chemical shifts (δP) of phosphorus (P)-containing probes and acidic strengths have been established in conjuction with density functional theory (DFT) calculations, rendering practical and reliable acidity scales for Brønsted and Lewis acidities at the atomic level. As illustrated for a variety of different solid and liquid acid systems, such as microporous zeolites, mesoporous molecular sieves, and metal oxides, the P NMR probe approaches were shown to provide important acid features of various catalysts, surpassing most conventional methods such as titration, pH measurement, Hammett acidity function, and some other commonly used physicochemical techniques, such as calorimetry, temperature-programmed desorption of ammonia (NH-TPD), Fourier transformed infrared (FT-IR), and H NMR spectroscopies.

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Section: Applications Of 31p Nmr For Acidity Characterization Of Vari...supporting

confidence: 67%

Section: Applications Of 31p Nmr For Acidity Characterization Of Vari...mentioning

confidence: 99%

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³¹P NMR Chemical Shifts of Phosphorus Probes as Reliable and Practical Acidity Scales for Solid and Liquid Catalysts

2017

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Engineering a Coordinatively Unsaturated Au–O–Ti3+ Structure Toward Unprecedented H2 Efficiency for Low-Temperature Propene Epoxidation with H2 and O2

Song¹,

Yuan²,

Ma³

et al. 2023

Engineering

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Lewis Acid Zeolites for Biomass Conversion: Perspectives and Challenges on Reactivity, Synthesis, and Stability

Luo

Lewis

Román‐Leshkov

2016

Annu. Rev. Chem. Biomol. Eng.

151

136

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Zeolites containing Sn, Zr, Hf, Nb, or Ta heteroatoms are versatile catalysts for the activation and conversion of oxygenated molecules owing to the unique Lewis acid character of their tetrahedral metal sites. Through fluoride-mediated synthesis, hydrophobic Lewis acid zeolites can behave as water-tolerant catalysts, which has resulted in a recent surge of experimental and computational studies in the field of biomass conversion. However, many open questions still surround these materials, especially relating to the nature of their active sites. This lack of fundamental understanding is exemplified by the many dissonant results that have been described in recent literature reports. In this review, we use a molecular-based approach to provide insight into the relationship between the structure of the metal center and its reactivity toward different substrates, with the ultimate goal of providing a robust framework to understand the properties that have the strongest influence on catalytic performance for the conversion of oxygenates.

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In-situ 31P MAS NMR probing of the active centers in Ti silicalite molecular sieve

Cited by 3 publications

References 25 publications

³¹P NMR Chemical Shifts of Phosphorus Probes as Reliable and Practical Acidity Scales for Solid and Liquid Catalysts

³¹P NMR Chemical Shifts of Phosphorus Probes as Reliable and Practical Acidity Scales for Solid and Liquid Catalysts

Engineering a Coordinatively Unsaturated Au–O–Ti3+ Structure Toward Unprecedented H2 Efficiency for Low-Temperature Propene Epoxidation with H2 and O2

Lewis Acid Zeolites for Biomass Conversion: Perspectives and Challenges on Reactivity, Synthesis, and Stability

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In-situ 31P MAS NMR probing of the active centers in Ti silicalite molecular sieve

Cited by 3 publications

References 25 publications

31P NMR Chemical Shifts of Phosphorus Probes as Reliable and Practical Acidity Scales for Solid and Liquid Catalysts

31P NMR Chemical Shifts of Phosphorus Probes as Reliable and Practical Acidity Scales for Solid and Liquid Catalysts

Engineering a Coordinatively Unsaturated Au–O–Ti3+ Structure Toward Unprecedented H2 Efficiency for Low-Temperature Propene Epoxidation with H2 and O2

Lewis Acid Zeolites for Biomass Conversion: Perspectives and Challenges on Reactivity, Synthesis, and Stability

Contact Info

Product

Resources

About

³¹P NMR Chemical Shifts of Phosphorus Probes as Reliable and Practical Acidity Scales for Solid and Liquid Catalysts

³¹P NMR Chemical Shifts of Phosphorus Probes as Reliable and Practical Acidity Scales for Solid and Liquid Catalysts