Hydrolysis reactions salt solutions

Hydrolysis is a special name given to acid-base reactions in which ions act as acids or bases. As a result of hydrolysis, many salt solutions are not pH neutral. 

In aqueous solution, OF2 oxidizes HCl, HBr, and HI (and thek salts), Hberating the free halogens. Oxygen difluoride reacts slowly with water and a dilute aqueous base to form oxygen and fluorine. The rate of this hydrolysis reaction has been determined (23). 

Aqueous sulfamic acid solutions are quite stable at room temperature. At higher temperatures, however, acidic solutions and the ammonium salt hydroly2e to sulfates. Rates increase rapidly with temperature elevation, lower pH, and increased concentrations. These hydrolysis reactions are exothermic. Concentrated solutions heated in closed containers or in vessels having adequate venting can generate sufficient internal pressure to cause container mpture. An ammonium sulfamate, 60 wt % aqueous solution exhibits mnaway hydrolysis when heated to 200°C at pH 5 or to 130°C at pH 2. The danger is minimised in a weU-vented container, however, because the 60 wt % solution boils at 107°C (8,10). Hydrolysis reactions are ... 

As metal ion concentration increases in the crevice, a net positive charge accumulates in the crevice electrolyte. This attracts negatively charged ions dissolved in the water. Chloride, sulfate, and other anions spontaneously concentrate in the crevice (Figs. 2.4 and 2.5). Hydrolysis produces acids in the crevice, accelerating attack (Reactions 2.5 and 2.6). Studies have shown that the crevice pH can decrease to 2 or less in salt solutions having a neutral pH. 

The hydrolysis reaction is very slow at ambient temperatures and is accelerated by boiling chromium salt solutions (5). The hydrolysis reaction is characterized by the transformation of the deep blue colored CrtHgOJg to green colored hydrolyzed olates. Another indication is tnatan aged or boiled Cr(III) salt solution has a higher neutralization equivalent than a fresh one due to the hydrolytically produced protons. One way to establish hydrolytic equilibria quickly is to add appropriate equivalents of bases such as NaOH to Cr(III) salt solutions. 

Hydrolysis of amino-alkylamino-l,2,5-thiadiazole 1-oxides 55 with concentrated aqueous HC1 gave the amidines 56 (Equation 4) <2001JME1231>. The hydrolysis reactions of 2-alkyl-4-amino-2,3-dihydro-l, 2,5-thiadiazol-3-one 1,1-dioxides 57 in the range 24-73 °C in buffered aqueous solutions gave the corresponding 2-amino-2-[(iV-alkyl-substituted-sulfamoyl)imino]acetic acid salts 58 (Equation 5) <1998JP0489>. 

In hydrolysis, a salt reacts with water. The ions that hydrolyze do so because a weak acid or a weak base is formed. The process of hydrolysis removes ions from the solution and is the driving force for the reaction. The reaction may produce a solution that is acidic, basic or neutral according to the following chart ... 

Tests allowing precise determination of the conditions to protect the soluble protein, and of the temperature at which the reaction was slow enough for X-ray data collection, were sought. To ascertain the best conditions for the determination of the structure of a productive lysozyme-substrate complex, the hydrolysis of bacterial cell walls and oligosaccharides was investigated both in high-salt solutions and in mixed solvents. 

At any rate, in addition to the hydrolysis reaction, there are a variety of additional oxidations in atmospheric aqueous solutions that can be carried out by N03. For example, N03 can oxidize S(IV) (see Chapter 8 Chameides, 1986a, 1986b Huie et a.l., 1995 Rudich et al., 1998) as well as halogens in sea salt. In the case of S(IV), the initiation reactions are... 

Regardless of the steps in the precipitation, the essential initial chemical reaction is the metal ion hydrolysis. Thus, in order to obtain uniform particles, different approaches are needed to manipulate the hydrolysis reaction, rather than to directly add strong bases to metal salt solutions. Two broadly successful methods have been ... 

H and NMR spectroscopic studies of 64 showed that the structure present in the solid state is retained in solution. That the reactivity of 64 is different compared to that of normal organozinc compounds became evident from a hydrolysis reaction of 64 with a carboxylic acid affording the corresponding zinc salt of the carboxylic acid and metallic zinc in a 1 1 ratio and pentamethylcyclopentadiene. This product formation suggests the... 

Properties of Iron(II) Salts. 1. Test a solution of Mohr s salt with an indicator. Write the equation of the iron(II) sulphate hydrolysis reaction. Pour in a sodium carbonate solution. What do you observe Write the equation of the reaction and explain the results obtained. 

Properties of Iron(III) Salts. 1. Determine the pH of an iron(III) chloride solution. Write the equation of the hydrolysis reaction of this salt. Which salt—iron(II) sulphate or iron(III) sulphate—hydrolyzes more strongly in solutions ... 

When compounds like 3,3 -dichlorobenzidine or aniline are mixed with sediment, they become irretrievable using organic solvents that should remove them from absorbed positions within natural organic matter or using salt solutions that should displace them from ion exchange sites (Appleton et al., 1980 Weber et al., 2001). Conditions that promote hydrolysis (see Chapter 13) do release much of these added amino derivatives. Thus, it appears that reactions between the basic amine and carbonyl functionalities in the natural organic matter explain the strong sorption seen (Stevenson, 1976). 

Hydrolysis.—A salt that contains as one of its constituents either a weak acid or a weak base will not dissolve in water to form a neutral solution. Water acts upon such a salt partially to reverse the reaction of neutralization, liberating equivalent parts of both acid and base. To obtain in solid form a normal salt that is subject to hydrolysis, it is necessary to have present in the solution considerable excess of either the acid or the base, depending upon the nature of the salt and the mother liquor from which the salt is crystallized will contain this excess. When the crystals have been drained from this mother liquor, they cannot be washed with the pure solvent, for this would leave them coated with a film of the aqueous solution of the normal salt, which would then undergo hydrolysis. If either the acid or the base of which the salt is composed should be difficultly soluble,... 

The precipitated potassium hydroxylamine disulfonate is expeditely filtered from the cold liquid, and the moist salt is dissolved in 500ml of N/2 hydrochloric acid. The solution is heated on the water bath for two hours and then well cooled in ice while 59g of potassium bicarbonate is added in small portions (foaming ) to the liquid in order to neutralize the free acid formed in the hydrolysis. The final solution should be adjusted to a faint add reaction with... 

Meszaros, Hermecz et al. transformed the quaternary 6,7.8,9-tetrahydro-pyrido[1.2-u]pyrimidinium salts (204) with acid to the carboxylic acids (205 R1 = H)257 and with sodium hydrogen carbonate solution to the l,6,7,8-tetrahydropyrido[l,2- ]pyrimidines (205 R = alkyl).7x2 8 From the alkaline hydrolysis reaction mixture, compounds 206 and 207 were also isolated.133 The quaternary salt (204 R = Me) was transformed with hydrazine hydrate to 6-methylpiperidone and with ammonia to 6-methyl-4-oxo-6.7,8,9-tetrahydro-4//-pyrido[1.2- ]pyrimidine-3-carboxamide and its A-methyl derivative.133... 

Related ammonium salts derived from amines, such as [CH3NH3]C1, [(CH3)2NH2]C1, and [(CH3)3NH]C1, also give acidic solutions because they too have cations with at least one dissociable proton. The pH of a solution that contains an acidic cation can be calculated by the standard procedure outlined in Figure 15.7. For a 0.10 M NH4C1 solution, the pH is 5.12. Although the reaction of a cation or anion of a salt with water to produce H30+ or OH - ions is sometimes called a salt hydrolysis reaction, there is no fundamental difference between a salt hydrolysis reaction and any other Bronsted-Lowry acid-base reaction. 

The chemical resolution process of Scheme 6 was developed into an economically favorable one by the ready recycle of both the FPA resolving agent and the combined (mostly S) amine fractions. FPA, which was prepared by methyl formate reaction with L-phenylalanine, was shown to be stable (no racemization and no hydrolysis) when the resolution and work-up processes were conducted within the pH range of 2-12 at temperatures below 25°C (higher temperatures were not studied). FPA meeting specification was isolated in yields of ca. 95% by simple acidification of its aqueous salt solutions and filtration. 

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