Strongly acidic or basic

Indole is a neutral compound but can be protonated or deprotonated under strongly acidic or basic conditions, respectively. The piC of the conjugate acid is about —2.4 that of the neutral compound is about 16.7 (1). 

Although reasonably stable at room temperature under neutral conditions, tri- and tetrametaphosphate ions readily hydrolyze in strongly acidic or basic solution via polyphosphate intermediates. The hydrolysis is first-order under constant pH. Small cycHc phosphates, in particular trimetaphosphate, undergo hydrolysis via nucleophilic attack by hydroxide ion to yield tripolyphosphate. The ring strain also makes these stmctures susceptible to nucleophilic ring opening by other nucleophiles. 

Hydrolysis of Nitriles. The chemical hydrolysis of nitriles to acids takes place only under strong acidic or basic conditions and may be accompanied by formation of unwanted and sometimes toxic by-products. Enzymatic hydrolysis of nitriles by nitrile hydratases, nittilases, and amidases is often advantageous since amides or acids can be produced under very mild conditions and in a stereo- or regioselective manner (114,115). 

Condensation reactions of hydroxymethyl groups on phenolic resoles and amines on melamine take place between pH 5 and 6 (Fig. 7.33). Only selfcondensations of hydroxymethyl substituents occur under strongly acidic or basic conditions. 

Like similarly activated carboxylate esters, these aromatic phosphonate diesters 30 were readily hydrolyzed to GLYH3 in good yield and purity under typical strongly acidic or basic conditions, or in a stepwise fashion under extremely mild conditions via the zwitterionic monoaryl esters 32 (44). Products such as 32 or 33 readily precipitated after a few hours at room temperature from aqueous acetone. 

Ethylene oxide polymerization may be initiated similarly by substances (alcohols, amines, mercaptans) capable of generating a hydroxyl group through reaction with the monomer. In the presence of strongly acidic or basic catalysts, successive addition of ethylene oxide molecules proceeds rapidly in the following manner ... 

C <4.7x10 Pa at 20 °C Water 20 mg at 20 °C Readily soluble in polar organic solvents Stable in neutral and weakly basic conditions Unstable in strongly acidic or basic conditions Stable in most of organic solvents such as acetone, acetonitrile and carbon tetrachloride Undergoes hydrolysis to yield methomyl oxime in alkaline solutions... 

In our retro-synthetic analysis, we envisioned the pyrrolidinylethanol side chain could be installed via the Ullmann ether formation or the analogous reachons from the aryl-iodide functional group. The key intermediate 9 (cis) in the Medicinal Chemistry route was not stable under strongly acidic or basic conditions since it was easily isomerized to the thermodynamically more stable trans-isomer 9a via... 

Lidocaine (lignocaine, 4.128, Fig. 4.5) is a typical representative of the class of aminoacylanilides. Lidocaine is a local anesthetic and an anti-arrhythmic agent that is very resistant to chemical hydrolysis even in strongly acidic or basic media. Only at higher temperature does lidocaine... 

Solutions in which the buffering action is due to the solvent rather than any added solute Strongly acidic or basic aqueous solutions will show httle change in pH when additional increments of acid or base are added (recall that the pK value for H3O+ is -1.74, and that for H2O is 15.74) . Because the solvent is in such high concentration, the buffering capacity for pseudo buffers is larger than for conventional buffers. See Buffer Capacity... 

The reduction of conjugated nitroalkenes such as S-nitrostyrenes to oximes provides easy access to a large number of versatile organic intermediates. However, despite their potential utility, many of these methods suffer from the use of strongly acidic or basic conditions, requirement of anhydrous conditions, and incompatibility with halogenated arenes. Eurther, some of the methods are inefficient for the preparation of aldoximes due... 

In comparison, photolysis of 83 in protic solvents such as methanol, ethanol, and water yields 84 as expected, but 84 forms mainly 87 rather than 85. Furthermore, in these solvents, the transient absorption (Amax 425 nm) due to 84 decays not with a second-order rate law but by biexponential decay. For example, the decay of transient absorption of 84 (A ax 420 nm) in water at pH 7 had rate constants of 2 x 10 and 3 x lO s Subsequent to the decay of 84, a transient absorption was formed with Amax 330 nm and a weak absorption band at 740 nm. However, this transient was formed much slower than 84 decayed. The absorption at 330 nm was described as a biexponential growth with rate constants of 584 and 21 s h The authors assigned this absorption to 88. Since 84 and 88 do not form and decay at the same rate, the authors theorized that 84 decays into 87, which then furnishes 88. Even though intermediate 87 does not absorb in the near UV, the authors characterized it with time-resolved IR spectroscopy. The authors demonstrated that, in hexane and a strongly acidic or basic aqueous solution, the photorelease from 83 goes through the formation of 87, whereas in near neutral aqueous solution, formation of 85 predominates. The authors concluded that the dehydration of intermediates 85 and... 

The titration of very weak acids and bases requires the use of strongly acidic or basic solutions. The determination of thermodynamic pKs is considerably more difficult in these media than in water-rich solutions. Thus, problems are always met when attempting to evaluate activity terms. Also, spectrophoto-metric and NMR titrations are frequently subject to perturbations induced by large changes in solvent composition. 

Strong acids spontaneously and completely dissociate in water and thus release all their acidity. The notion of pH shows up the notion of strong acidity or basicity, as related in the following relation (Fig. 3.27). 

Furthermore, the amphoteric behavior of the aluminum ion can be shown in sulfur dioxide as readily as in water. Just as AI(OH), is insoluble in water but dissolves readily in either a strong acid or basic solution, AMS03)3 is insoluble in liquid sulfur dioxide. Addition of either base (SO2-) or acid (SO2 ) causes the aluminum sulfite to dissolve, and it may be reprecipitated upon neutralization. 

The minute quantity of adsorbate remaining on the column after weakly bound probe has desorbed is chemisorbed to strongly acidic or basic sites on the substrate. The desorption profile obtained by ramping the column temperature is an index of the range of effective bond strength between the solid and adsorbed vapor. The flame ionization detector also registers desorption of adventitious organic contaminants polytherms with no probe on the column must be obtained separately so that sorbate and contaminant desorption can be deconvolved. 

Acids or Bases. Liable to polymerize violently, especially in contact with strong acidic or basic catalysts. Hydroquinone is added as stabilizer but may lose its effectiveness after a short storage time.3... 

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