Hydrolysis acid salts

Under conditions of extreme acidity or alkalinity, acryhc ester polymers can be made to hydroly2e to poly(acryhc acid) or an acid salt and the corresponding alcohol. However, acryhc polymers and copolymers have a greater resistance to both acidic and alkaline hydrolysis than competitive poly(vinyl acetate) and vinyl acetate copolymers. Even poly(methyl acrylate), the most readily hydroly2ed polymer of the series, is more resistant to alkah than poly(vinyl acetate) (57). Butyl acrylate copolymers are more hydrolytically stable than ethyl acrylate copolymers (58). 

The 7 6 salts are the acid salts of the normal 4 3 hexaniobates. The formulas can be written as M2H(Nb 02C)) (aq). Further hydrolysis can take place. At pH ca 4.5, the irreversible precipitation of niobic acid occurs. 

Also, basic hydrolysis or pethydtolysis of diacyl peroxides has been used to produce petoxycatboxyhc acids (44,181). Pethydtolysis produces two moles of the petoxycatboxyhc acid salt ... 

Table 1 Hsts a number of common inorganic coagulants. Typical iron and aluminum coagulants are acid salts that lower the pH of the treated water by hydrolysis. Depending on initial raw water alkalinity and pH, an alkah such as lime or caustic must be added to counteract the pH depression of the primary coagulant. Iron and aluminum hydrolysis products play a significant role in the coagulation process, especially in cases in which low turbidity influent waters benefit from the presence of additional colHsion surface areas.

Hydrolysis. The lactone is easily hydroly2ed by alkaUes to the corresponding salts of coumarinic acid or o-hydroxy-i j -cinnamic acid [495-79 ]. Coumarinic acid salts are odorless. Coumarinic acid and salts revert to coumarin upon acidification with inorganic acids. Alkaline fusion of coumarin yields salts of sahcyhc and acetic acids. 

Lower oxidation states are rather sparsely represented for Zr and Hf. Even for Ti they are readily oxidized to +4 but they are undoubtedly well defined and, whatever arguments may be advanced against applying the description to Sc, there is no doubt that Ti is a transition metal . In aqueous solution Ti can be prepared by reduction of Ti, either with Zn and dilute acid or electrolytically, and it exists in dilute acids as the violet, octahedral [Ti(H20)6] + ion (p. 970). Although this is subject to a certain amount of hydrolysis, normal salts such as halides and sulfates can be separated. Zr and are known mainly as the trihalides or their derivatives and have no aqueous chemistry since they reduce water. Table 21.2 (p. 960) gives the oxidation states and stereochemistries found in the complexes of Ti, Zr and Hf along with illustrative examples. (See also pp. 1281-2.)... 

The Dissociation Constant of Nitric Add. Alodcrately Weak Acids. The Variation of J with Temperature. Proton Transfers between Solute Particles. A Proton Transfer in Methanol Solution. Proton Transfers with a Negative Value for. / . The Hydrolysis of Salts. Molecules with Symmetry. Substituted Ammonium Ions. Deuteron Transfers in D2(). The Dissociation of Molecular Ions. 

Saponification (Section 21.6) An old term for the base-induced hydrolysis of an ester to yield a carboxylic acid salt. 

Neutralisation reactions, or addimetry and alkalimetry. These include the titration of free bases, or those formed from salts of weak acids by hydrolysis, with a standard acid (addimetry), and the titration of free acids, or those formed by the hydrolysis of salts of weak bases, with a standard base (alkalimetry). The reactions involve the combination of hydrogen and hydroxide ions to form water. 

Solutions which prevent the hydrolysis of salts of weak acids and bases. If the precipitate is a salt of weak acid and is slightly soluble it may exhibit a tendency to hydrolyse, and the soluble product of hydrolysis will be a base the wash liquid must therefore be basic. Thus Mg(NH4)P04 may hydrolyse appreciably to give the hydrogenphosphate ion HPO and hydroxide ion, and should accordingly be washed with dilute aqueous ammonia. If salts of weak bases, such as hydrated iron(III), chromium(III), or aluminium ion, are to be separated from a precipitate, e.g. silica, by washing with water, the salts may be hydrolysed and their insoluble basic salts or hydroxides may be produced together with an acid ... 

There are many parallels between phosphates and sulfates of aliphatic alcohols. Both types of surfactants contain ester bonds undergoing hydrolysis in acid solutions. In that case the starting materials are received once more. By dry heating of the salts above a temperature of 140°C destruction will occur forming the corresponding alkenes and an inorganic acid salt. In the same way as sulfonic and sulfinic acids are formed by C-S bonds, C-P bonds lead to phosphonic and phosphinic acids. 

The reaction of step 2 is carried out by heating the reagents with various acid catalysts, such as orthophosphoric acid or its acid salts, bringing the pH down to 2.3-3.2 [4]. The Igepon A type of surfactant is quite susceptible to hydrolysis, particularly on the alkaline side, as is characteristic for most esters of carboxylic acids. It is therefore used most advantageously at a fairly neutral pH, such as combination soap-syndet toilet bars. 

The first case corresponds to the hydrolysis of salts of strong acids and weak bases. This can generally be shown as ... 

In hydrolysis, the salt and water are the reactants and the acid and the base are the products. 

Phosphoric and polyphosphoric acid esters Perfluorinated anionics Sulfonic acid salts Strong surface tension reducers Good oil in water emulsifiers Soluble in polar organics Resistant to biodegradation High chemical stability Resistant to acid and alkaline hydrolysis... 

It also follows that protonation of the triazine ring makes it more susceptible to attack by nucleophilic reagents unless the reagent itself is also protonated. If the triazine ring remains unprotonated when a nucleophilic base, such as an alkylamine, is present as its acid salt the reaction is slower, of course. Cyanuric chloride itself is a very weak base that becomes protonated only under strongly acidic conditions. Thus step 1 in Scheme 11.2 can be carried out in aqueous solution even at pH 2 without risk of undesirable hydrolysis of cyanuric chloride, water being an extremely weak nucleophile. 

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>. 

The synthesis of compound 27 was initiated with the treatment of ke-toester 29, reported by Yoshida et al. [25], with ethyl orthoformate in acetic acid, followed by reaction with (l.R,2S)-2-fluoro-1-cyclopropylamine p-toluenesulfonic acid salt in the presence of triethylamine to yield an enam-inoketoester intermediate, cyclization of which under NaH in dioxane yields the 5-nitroquinolone derivative (30). Reduction of the nitro group of compound 30 followed by acid hydrolysis provides compound 27 via the amino-quinolone derivative (31), according to Scheme 7. 

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 ... 

Hydrazine salts have been prepared by the action of hypochlorites on ammonia1 or urea 2 by the hydrolysis of salts of sulfohydrazimethylene disulfonic acid 3 by the hydrolysis of triazoacetic acid 4 by the reduction of diazoacetic ester 5 by the reduction of nitroguanidine followed by hydrolysis 6 by the reduction of the nitroso derivatives of hexamethylene tetramine 7 by the reduction of nitrates or nitrites with zinc in neutral solution 8 by the action of sodium bisulfite on hyponitrous acid... 

Chemical instability of medicinal agents may take many forms, because the drugs in use today are of such diverse chemical constitution. Chemically, drug substances are alcohols, phenols, aldehydes, ketones, esters, ethers, acids, salts, alkaloids, glycosides, and others, each with reactive chemical groups having different stability characteristics. Chemically, the most frequently encountered destructive processes involve hydrolysis and oxidation. 

The classic caustic fusion of sulfonic acid salts has been used for preparing 2,6-dinaphthol and its derivatives. Other more recent procedures have employed the direct hydrolysis of aryl bromides and the oxidation of aryl Grignard reagents. ... 

The kinetics of the hydrolysis reactions of 4-amino-2-phenethyl- (354 R = PhCH2CH2) and 4-amino-2-cyclohexyl-2,3-dihydro-3-oxo-l,2,5-thiadiazole 1,1-dioxide (354 R = CeHii) have been investigated in the pH range 1-10 at 24-73 °C. The products are the corresponding new compounds 2-anuno-2-[(A -substituted-sulfamoyl)imino]acetic acid salts (355 R = PhCH2CH2 or CeHn) which hydrolyse further, in a slow reaction, to the sulfamide and oxalic acid derivatives. ... 

After the hydrolysis of the methyl m-nitrobenzoate it is essential that the solution of the sodium salt be poured into the acid. If acid be added to the salt in the usual way, a less soluble acid salt separates and as this cannot be entirely removed from the w-nitrobenzoic acid even on long digestion with hydrochloric acid, a product is obtained which does not dissolve completely in ether. 

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