Br0nsted

Figure C2.12.2. Fonnation of Br0nsted acid sites in zeolites. Aqueous exchange of cation M witli an ammonium salt yields tlie ammonium fonn of tlie zeolite. Upon tliennal decomposition ammonia is released and tire proton remains as charge-balancing species. Direct ion-exchange of M witli acidic solutions is feasible for high-silica zeolites.

In the Br0nsted-Lowry view an acid doesn t dissociate in water it transfers a pro ton to water Water acts as a base... [Pg.34]

Clearly the two reactions are analogous and demonstrate that the reaction between hydroxide ion and hydrogen bromide is simultaneously a Brpnsted acid-base reaction and a Lewis acid Lewis base reaction Br0nsted acid-base reactions constitute a sub category of Lewis acid Lewis base reactions... [Pg.46]

The Br0nsted-Lowry approach to acids and bases is more generally use ful than the Arrhenius approach... [Pg.50]

The Lewis definitions of acids and bases provide for a more general view of acid-base reactions than either the Arrhenius or Br0nsted-Lowry pic ture A Lewis acid is an electron pair acceptor A Lewis base is an electron pair donor The Lewis approach incorporates the Br0nsted-Lowry approach as a subcategory m which the atom that accepts the electron pair m the Lewis acid is a proton... [Pg.50]

Achiral (Section 7 1) Opposite of chiral An achiral object is supenmposable on its mirror image Acid According to the Arrhenius definition (Section 1 12) a substance that ionizes in water to produce protons Accord mg to the Br0nsted-Lowry definition (Section 1 13) a sub stance that donates a proton to some other substance According to the Lewis definition (Section 1 17) an electron pair acceptor... [Pg.1274]

Dissociation Constants for Selected Br0nsted Acids (Table 4 2, p 135)... [Pg.1327]

The acid dissociation constant has the same fonn in Br0nsted-Lowry as in the Aiihenius approach, but is expressed in the concentration of H30" rather than H". The concentration temns [H30 j and [H" ] are considered equivalent quantities in equilibrium constant expressions. [Pg.35]

This equation is known as the Br0nsted-Bjerrum equation. Because y% appears in the denominator, it explicitly acknowledges the premise of TST that there is an equilibrium between the reactants and the transition state. Equation (9-27) provides the basis for understanding the direction and magnitude of rate effects arising from changes of reaction medium. This approach will be used to formulate effects of solvent and inert electrolytes in the sections that follow. [Pg.204]

This composite rate constant is predicted to have a different ionic strength dependence for the two schemes. According to the Br0nsted-Debye-Hiickel equation, the composite rate constant for Eq. (9-76) will be independent of ionic strength if Scheme ... [Pg.213]

The Br0nsted coefficient /3 lies in the range 0 < /3 < 1, and has much the same mechanistic significance as a. It is a measure of progress along the reaction coordinate. The closer /3 is to unity, the more complete proton transfer is from substrate to base in the transition state. [Pg.236]

Br0nsted s correlation was developed some years before Hammett s. Here we present a formulation that shows how both LFERs are related for general acid catalysts. For the sake of simplicity, we ignore the statistical factors of p and q. The Hammett equation applied to the values of bh is... [Pg.236]

BR0NSTED-ACID-CATALYZED DIELS-ALDER REACTION... [Pg.185]

Br0nsted-Acid-Catalyzed Diels-Alder Reaction... [Pg.186]

Two acid-base theories are used in organic chemistry today the Br0nsted theory and the Lewis theory. These theories are quite compatible and are used for different purposes. ... [Pg.327]

Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...