Negligible acidity

The evaluation of the acid properties of calcined materials was based on the assumption that n-butylamine molecules interact with all acid sites, and the total acidity of the sample studied can be determined from the maximum amount adsorbed. Shown in Fig. 2 are thermogravimetric curves for n-butylamine thermodesorption, which were used to evaluate the amount of medium and strong acid sites for both samples. Thermodesorption of n-butylamine from CeMCM-41 exhibits three distinct ranges (i) desorption of physically adsorbed amine bellow 230 °C (ii) desorption of n-butylamine from medium acid sites at 230 - 410 °C (0.25 mmol/g), and (iii) its desorption from strong acid sites at 410 - 590 °C (0.21 mmol/g). However, only one weight loss was observed for pure silica MCM-41 due to thermodesorption of physically adsorbed amine, indicating negligible acidity of this material. 

Four groups bonded to the central nitrogen atom, which may be the same or different -> Negligible acid or base properties and little effect on pH... 

In all of the oxygen-sulfur interchange reactions, optimum catalysis is achieved with aluminosilicates of low or negligible acidity. It is probable that the exchange proceeds via a multistep catalytic process. In... 

From Table 1, we can also compare SAPO-37 activities with those obtained with NaY zeolite. The latter has a negligible acidity and, thus, its n-heptane cracking activity corresponds practically to thermal reactions. The higher activity of SAPO-37 for n-heptane cracking, and... 

A Grignard reagent is a strong nucleophile. It attacks any slightly positively charged species. Thus, when treated with water, very negligibly acidic, it deprotonates the water molecule. 

Values of Wsl can l>c directly obtained from contact angle measurement (CAM) [162]. In case of a negligible acid-base interaction, Wsl = WJl, and Ws l is obtained... 

The substances with negligible acidity are those such as CH4 that contain hydrogen but do not demonstrate any acidic behavior in water. Their conjugate bases are strong bases, reacting completely, abstracting protons from water molecules to form OH ions. 

Common strong bases are the ionic hydroxides of alkali metals and the heavy alkaline earth metals. The cations of strong bases have negligible acidity. 

Label each of the following as being a strong add, a weak acid, or a species with negligible acidity. In each case... 

The component of the surfaces under investigation can be determined by contact angle measurements, using a nonpolar liquid as the interaction of a nonpolar liquid is restricted to dispersive forces [83], The nonpolar liquid should have a high surface tension (such as DIM) to avoid the spreading of the liquid. In the case of negligible acid-base interactions (i.e., for nonpolar solids), the total work of adhesion between a solid and a liquid... 

Standard solutions with concentrations below 1 mg/L should be prepared in diluted acid to prevent adsorption of the standard by glass. The acid concentration should be that low, that a negligible acid concentration exists by preparation between the standard series individually and the samples. 

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