Positive charge exchange reaction

Weak-Base Anion Exchange Resin They can be operated only in the acidic pH region where the primary, secondary, or tertiary amine functional groups are protonated, and thus can act as positively charged exchange sites for anions. The weak-base resins remove free mineral acidity, such as HCl or H2SO4, but cannot split salts. Consider the following reaction ... 

In an APCI interface the column effluent enters a heated nebulizer where the pneumatically assisted desolvation process is almost completed. While still in the spray chamber, ionization of analytes is initiated by corona discharge. The ionization mechanisms in APCI are almost identical to those in conventional medium pressure chemical ionization (7). Positive ion formation can be achieved by proton transfer, adduct formation or charge exchange reactions, while in the negative mode ions are formed due to proton abstraction, anion attachment and electron capture reactions. The APCI interface is compatible with flow rates exceeding 1 ml/min and will... 

Nucleophilic Reagents. In contrast to electrophilic reactions, nucleophiles attack positively charged, even carbons ia the chain. The reactions lead to the exchanging of substituents or terminal residues. Thus, SR and OR groups, or halogen atoms can be exchanged by other suitable nucleophiles (4,69,70), for example, by aniline ... 

Silver oxide acts by exchanging hydroxide ion for iodide ion in the quatei nary salt, thus providing the base necessary to cause elimination. The acluE elimination step is an 0,2 reaction (Section 11.8) in which hydroxide ioi removes a proton at the same time that the positively charged nitrogen atom leaves. 

In the first investigation 20), ethylene in the collision chamber was bombarded with positive ions, and the intensities of the fragment ions, obtained after the charge exchange, were recorded. The mass spectra were thus not normalized. At low pressure only primary ions were observed that were formed from ethylene in the charge exchange, but at higher pressures also secondary and tertiary ions were obtained as a result of ion-molecule reactions between the primary ions and the ethylene molecules in the collision chamber. 

It is worth mentioning that both the carboxylation of epoxides and anilines are acid-base reactions, which do not entail redox processes. Therefore a catalyst active in these reactions must provide acid-base functionality. In this perspective, positively charged gold could be the real player, although a co-catalytic or promotion effect of ze-rovalent gold could also be important. Therefore the catalysts for the oxidative carbonylation of aniline, supported on Merck Ion-exchanger IV, could be actually bifunctional. On one side, Au could catalyze the oxidation of CO with O2 to CO2, a reaction for which it is... 

The positively charged phosphonium ligand was intercalated in the hectorite and was used to catalyze olefin hydroformylation.156 Cu(II)-exchanged clays were tested as catalysts in the cyclopropanation reaction of styrene with... 

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