Basic or acidic

Another important parameter that may affect a precipitate s solubility is the pH of the solution in which the precipitate forms. For example, hydroxide precipitates, such as Fe(OH)3, are more soluble at lower pH levels at which the concentration of OH is small. The effect of pH on solubility is not limited to hydroxide precipitates, but also affects precipitates containing basic or acidic ions. The solubility of Ca3(P04)2 is pH-dependent because phosphate is a weak base. The following four reactions, therefore, govern the solubility of Ca3(P04)2. 

If the oxidation or reduction of H2O is carried out externally using the generator cell shown in Figure 11.25, then H3O+ or OH can be dispensed selectively into a solution containing a basic or acidic analyte. The resulting reaction is identical to that in an acid-base titration. Coulometric acid-base titrations have been used for... 

Finish removers are appHed by bmshing, spraying, troweling, flowing, or soaking. Removal is by water rinse, wipe and let dry, or solvent rinse. Removers may be neutral, basic, or acidic. The viscosity can vary from water thin, to a thick spray-on, to a paste trowel-on remover. The hazard classification, such as flammable or corrosive, is assigned by the U.S. Department of Transportation (DOT) for the hazardous materials contained in the remover. 

Positionalisomeri tion occurs most often duting partial hydrogenation of unsaturated fatty acids it also occurs ia strongly basic or acidic solution and by catalysis with metal hydrides or organometaUic carbonyl complexes. Concentrated sulfuric or 70% perchloric acid treatment of oleic acid at 85°C produces y-stearolactone from a series of double-bond isomerizations, hydration, and dehydration steps (57). 

The effect of pH is rarely of use for pK measurement it is more often of use in identifying the site of protonation/deprotonation when several basic or acidic sites are present. Knowing the incremental substitutent effects Z of amino and ammonium groups on benzene ring shifts in aniline and in the anilinium ion (40), one can decide which of the nitrogen atoms is protonated in procaine hydrochloride (problem 24). 

Esters can be hydrolyzed in either basic or acidic solution. In acidic solution, the reaction is reversible. The position of the equilibrium depends on the relative concentra-... 

Attempts have been made to deduce the structure of the predominant form of a potentially tautomeric compound from the shifts which occur in the ultraviolet spectrum of the compound in question on passing from neutral to basic or acidic solutions. The fact that no bathochromic shifts were observed for 2- and 4-hydroxy quinoline and 1-hydroxyisoquinoline under these conditions was taken as evidence that they existed in the oxo form [similar work on substituted quinol-4-ones led to no definite conclusions ]. A knowledge of the dissociation constants is essential to studies of this type, and the conclusions can, in any case, be only very tentative. A further dif-... 

Hydrolysis Conversion of Nitriles into Carboxylic Acids A nitrile is hydrolyzed in either basic or acidic aqueous solution to yield a carboxylic acid plus ammonia or an amine. 

The semicrystalline polyesters of the terephthalate and naphthalate family are resistant to a wide range of chemicals at room temperature, including water, alcohols, ketones, ethers, glycols, chlorinated solvents, aliphatic hydrocarbons, and oils. They are slowly hydrolyzed in boiling water and rapidly degraded in strongly basic or acidic medium. 

The reduction of CI04- can be conducted in either basic or acidic solutions. The two half-reactions are... 

Hall and his co-workers43 synthesized several 2-oxabicyclo[2.1.1 ]hexan-3-ones from the corresponding 3-chlorocyclobutanecarboxylic acids. These monomers polymerized readily when heated with a variety of basic or acidic initiators. Some of the results of the polymerization are listed in Table 2. 

The results obtained indicate that in the reaction between phenol and methanol, formaldehyde is the trae methylating agent when basic catalysts are used. This indicates that the type of transformation occurring with methanol is the factor that mainly differentiates performances in phenol methylation when catalyzed by either basic or acid catalysts. The catalyst plays its role in the generation of the methylating species the nature of the latter then determines the type of phenolic products obtained. 

Classical Aldol. Aldol reaction is an important reaction for creating carbon-carbon bonds. The condensation reactions of active methylene compounds such as acetophenone or cyclohexanone with aryl aldehydes under basic or acidic conditions gave good yields of aldols along with the dehydration compounds in water.237 The presence of surfactants led mainly to the dehydration reactions. The most common solvents for aldol reactions are ethanol, aqueous ethanol, and water.238 The two-phase system, aqueous sodium hydroxide-ether, has been found to be excellent for the condensation reactions of reactive aliphatic aldehydes.239... 

Partial hydrolysis of nitrile gives amides. Conventionally, such reactions occur under strongly basic or acidic conditions.42 A broad range of amides are accessed in excellent yields by hydration of the corresponding nitriles in water and in the presence of the supported ruthenium catalyst Ru(0H)x/A1203 (Eq. 9.19).43 The conversion of acrylonitrile into acrylamide has been achieved in a quantitative yield with better than 99% selectivity. The catalyst was reused without loss of catalytic activity and selectivity. This conversion has important industrial applications. 

Prokaryotic cells express hundreds to thousands of proteins while higher eukaryotes express thousands to tens of thousands of proteins at any given time. If these proteins are to be individually identified and characterized, they must be efficiently fractionated. One-dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) has typically been use to study protein mixtures of <100 proteins. Onedimensional electrophoresis is useful because nearly all proteins are soluble in SDS, molecules ranging from approximately 10,000 to 300,000 molecular weight can be resolved, and extremely basic or acidic proteins can be visualized. The major disadvantage to one-dimensional gels is that they are not suitable for complex mixtures such as proteins from whole cell lysates. 

The UV spectra of several 5-aminoimidazoles (180) have been examined in ethanol or acetonitrile solution (Table IX). A change of pH from neutral to either basic or acidic pH results in a shift of maxima. For example, compound (180 R = R2 = Me) in ethanolic solution with 1 M HC1 gave two maxima at 210 nm (e 1470) and 243 nm (e 2040), and in ethanolic solution with 1 M NaOH gave one maxima at 216 nm (e 10720) (87TH1). Also, AIRs (180 R1 = ribonucleoside, R2 = H) displayed a single maxima... 

A technique that is suitable for capture of trace levels of precious metal is the use of an ion exchange resin on which is loaded a basic or acidic salt of a phosphine li-gand.[36] A portion of the disclosure of US 5,114,473 reads ... 

Organic cyanide compounds, or nitriles, have been implicated in numerous human fatalities and signs of poisoning — especially acetonitrile, acrylonitrile, acetone cyanohydrin, malonitrile, and succinonitrile. Nitriles hydrolyze to carboxylic acid and ammonia in either basic or acidic solutions. Mice (Mus sp.) given lethal doses of various nitriles had elevated cyanide concentrations in liver and brain the major acute toxicity of nitriles is CN release by liver processes (Willhite and Smith 1981). In general, alkylnitriles release CN much less readily than aryl alkylnitriles, and this may account for their comparatively low toxicity (Davis 1981). 

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