Silver displacement reactions

Alkyl esters of trifluoromethanesulfonic acid, commonly called triflates, have been prepared from the silver salt and an alkyl iodide, or by reaction of the anhydride with an alcohol (18,20,21). Triflates of the 1,1-dihydroperfluoroalkanols, CF2S020CH2R can be prepared by the reaction of perfluoromethanesulfonyl fluoride with the dihydroalcohol in the presence of triethylamine (22,23). Triflates are important intermediates in synthetic chemistry. They are among the best leaving groups known, so they are commonly employed in anionic displacement reactions. 

Radio-tracers have been used to study silver deposition, and it has been shown that when certain inhibitors or complexing agents are present the displacement reaction may be markedly affected ... 

With bromine monochloride at 0°C in a variety of solvents, 1 was converted into addition products, the product distribution being a function of solvent. A change in halogenating agent also altered the product ratio. (Scheme 4) Nucleophilic displacement reactions between these products and silver fluoride was found to cause preferential bromine substitution (83G149). 

SN displacement reactions, 27-9 a-Selenocyclohexanones, 77 Senecioyl chloride, 33 Silmagnesiation, platinum-catalysed, 8 Silametallation of terminal alkynes, 7-9 Silver acetylide, 49 Silver trifluoroacctate, 42,127 Silyl cuprates, 7... 

Glycosyl perchlorates are formed on treating glycosyl halides with silver perchlorate in inert solvents, and react readily with alcohols to give glycosides, but they have been reported to explode when heated > so their use in direct displacement reactions has understandably been limited. These esters have, however, presumably been present as intermediates in the many reactions of glycosyl halides with alcohols in which silver perchlorate was used as a catalyst (e.g. Ref. s )). 

Bromosilatrane (50) can be involved in electrophilic displacement reactions with silver compounds26,27 to give products 21, 37, 61 and 62 (equations 77-80). 

Figure 4.2 The mixing of a silver sulfate solution with an aluminum chloride solution, results in the formation of aqueous aluminum sulfate and the precipitation of silver chloride. This is an example of a double displacement reaction.

In the example of a double displacement reaction below, a silver sulfate (Ag2S04) solution is mixed with an aluminum chloride (AlCl3) solution. One of the products, silver chloride (AgCl), precipitates out of the solution as a solid. The (s) following the formula for silver chloride shows that it is a solid. 

Treatment of 1,3-dicarbonyl compounds with DBP in a methoxide/methanol system affords 2-alkyl-4-[(phenylsulfonyl)methyl]furans, where reaction proceeds by Initial addition-elimination on the vinyl sulfone moiety. In contrast, silyl enol ethers in the presence of silver tetrafluoroborate resulted in products derived from Sn2 displacement at the allylic site.11 Anions derived from 1,3-dicarbonyls substituted at the C-2 position are found to induce a complete reversal in the mode of ring closure.12 The major products obtained are 3-[(phenylsulfonyl)methyl]-substituted cyclopentenones. The internal displacement reaction leading to the furan ring apparently encounters an unfavorable Ai -interaction in the transition state when a substituent group is present at the 2-position ol the dicarbonyl compound. This steric Interaction is not present in the transition state leading to the cyclopentenone ring. 

Results of experiments, such as the one in Figure 12, in which displacement reactions take place are summarized in the activity series, a portion of which is shown in Table 4. In the activity series, elements are arranged in order of activity with the most active one at the top. In general, an element can displace those listed below it from compounds in solution, but not those listed above it. Thus, you can use the activity series to make predictions about displacement reactions. You could also predict that no reaction would happen, such as when silver is put into a copper(II) nitrate solution. 

A potentiometric titration will be run using a solution of your cobalt(III) complex and aqueous silver nitrate (AgN03) as a titrant. AgN03, which is soluble in aqueous solution, undergoes a double displacement reaction with the cobalt ammine complex according to equation (2.10). 

Metal displacement reaction. Experiment demonstrating the displacement of silver from solution by copper. (Courtesy Jerry Mason/Photo Researchers, Inc.)... 

S. Winstein andR. E. Buckles, The role of neighboring groups in displacement reactions. 1. Retention of configuration in the reaction of some dihahdes and acteoxyhahdes with silver acetate, J. Am. Chem. Soc., 64 (1942) 2780-2801. 

During the Middle Ages ( 400-1400 ad), another displacement reaction completely misled alchemists into foolishly pursuing a philosopher s stone that was believed to have the power to turn base metals such as iron and lead into more precious metals such as silver and gold. The alchemists ignorance of relative activities of metals led them to believe that they had turned iron into a more precious metal when they inserted an iron rod into a blue copper(II) sulfate solution. In fact, the following displacement reaction had occurred, plating shiny copper metal onto the iron rod. 

When a solution of 25.0 g of silver nitrate in 100 g of water is mixed with a solution of 10.0 g of magnesium chloride in 100 g of water, a double displacement reaction occurs. The balanced chemical equation is shown below. Which is the limiting reactant ... 

An oxidation-reduction reaction is one in which electrons are transferred from one reactant to another. They are often called redox reactions for short. Oxidation is the loss of one or more electrons by a species. The species losing electrons is oxidized. Reduction is the gain of one or more electrons by a species, and that species is reduced. Oxidation and reduction always occur simultaneously. The single-displacement reaction of copper metal with silver nitrate solution is both a single replacement reaction and an oxidation-reduction reaction. 

The Hunsdiecker reaction is closely related to the Simonini reaction.5 As a matter of fact, the first half of the Simonini reaction is the Hunsdiecker reaction. Therefore, treatment of one equivalent of silver carboxylate 1 with iodine gives alkyl iodide 3. In the presence of another equivalent of silver carboxylate 1, an S 2 displacement reaction takes place, affording ester 4. Since there are so many practical ways to make esters, the Simonini reaction is no longer widely used. 

The displacement of hydrogen from water or acids is just one type of single-displacement reaction. Other elements can also be displaced from their compounds. For example, copper metal reduces aqueous solutions of ionic silver compounds, such as silver nitrate, to deposit silver metal. The copper is oxidized. 

Beiner et al. tested the collecting capacity of several metal compounds for some volatile sulfur substances. They noted high enrichment rates and good selectivity for silver sulfide. It was used in combination with membrane extraction, thermodesorption, and GC-MS to analyze sulfides, thiols, and tetrahydrothiophene from water samples. Detection limits down to the lower ng/1 range were achieved. The disadvantages of the method are the experimental equipment, the long analysis times, and displacement reactions between the matrix and analytes on the sorbent s surface. 

The positive value of E indicates that the displacement of silver by nickel resulting from oxidation of Ni metal and reduction of Ag is a spontaneous process. Remember that although we multiply the silver half-reaction by 2, the reduction potential is not multiplied. 

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