Lewis acidity/basicity

For the studied catechol methylation reaction the catalyst structure and surface properties can explain the catalytic behaviour As mentioned above, the reaction at 260-350°C has to be performed over the acid catalysts. Porchet et al. [2] have shown, by FTIR experiments, the strong adsorption of catechol on Lewis acid/basic sites of the Y-AI2O3 surface. These sites control the reaction mechanism. 

Due to the formation of Ca/Al mixed oxide on the surface, the Ca -modified alumina has a completely different structure compared to the spinel one This leads to a different type of surface Lewis acid/basic sites, rendering the catalyst 30 times less active. 

Correlation between electrophilicity-nucleophilicity and Lewis acidity-basicity ... 

Spectroscopic Methods of Detecting Lewis Acidity/Basicity and Bronsted Acidity/Basicity... 

Many methods have been developed to detect the Lewis acidity/basicity and Bronsted acid-ity/basicity. Liquid- or gas-phase titration, UV spectroscopy, and calorimetry are some of the non-spectroscopic methods of detecting acidity and basicity of an oxide material.26 However, we shall confine our discussion to the spectroscopic methods of detecting the acidity and basicity of an oxide material. IR, Raman, and NMR are the common spectroscopic techniques used to quantify the acidity or basicity of an oxide material. 

Describe the spectroscopic methods for detection of Lewis acidity/basicity and Bronsted acid-ity/basicity of metal oxides, and explain why pyridine (in spite of its toxicity and low volatility) is a popular choice as an adsorbate molecule. 

Ionic liquids can be compared to any other liquid in that the reactivity of a species will depend upon its relative activity in solution. To this end it is important to consider the relative Lewis and Bronsted acids that can interact with the solutes to affect their activity. It is also important to remember that ionic liquids with discrete anions have wider potential windows and what we therefore hope to achieve with them is more susceptible to the presence of reactive species. The influence of impurities on the electrochemical behavior of an ionic liquid will depend upon the relative Lewis acidity/basicity of the liquid and of the redox process in question. Eutectic-based ionic liquids behave very differently from ionic liquids with discrete... 

The advantage of this empirical model is that the systematic variation in the solvent data can now be described using fewer variables than in the original data set. Eventually, an attempt is made to explain the factors F and F2, which themselves define a new coordinate system, by considering an underlying physical or chemical meaning e.g. polarity, polarizability, or Lewis acidity/basicity of the solvent molecule), thus leading finally to a new solvent classification. 

Figure 15.11 shows x-ray diffraction (XRD) profiles of ceria powders produced by precipitation. The XRD data for the synthesized particles show characteristics of Ce02 with a typical fluorite stracture. Since the starting cerium salt was Ce(N03)3, it required the oxidation of Ce + to Ce + in the solution. In this system, there is a possible cause for this oxidation. According to the Lewis definition of acids and bases, Ce is a Lewis base and Ce + is a Lewis acid. Basic solution therefore favors Ce compared with Ce . The crystallite size was calculated from the Scherrer formula ... 

Lewis acidity, basicity, H-bonding and complexing of organic arsenic,... 

Lewis acidity, basicity, H-bonding and complexing AsHj + HCl ----------------------- AsH Cl + Hj... 

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