Water hydrolysis

When esters such as ethyl acetate are shaken with water, hydrolysis slowly occurs, and ultimately an equilibrium is attained ... 

The Lewis base that acts as the nucleophile often is but need not always be an anion Neutral Lewis bases can also serve as nucleophiles Common examples of substitutions involving neutral nucleophiles include solvolysis reactions Solvolysis reactions are substitutions m which the nucleophile is the solvent m which the reaction is carried out 8olvolysis m water (hydrolysis) converts an alkyl halide to an alcohol... 

Commercial use of many chlorinated derivatives imposes stress on the stabHity of the solvent. Inhibitors classified as antioxidants (qv), acid acceptors, and metal stabilizers are added to minimize these stresses. AH the chloriaated derivatives hydrolyze at a slow but finite rate when dissolved ia water. Hydrolysis of chloriaated solvents typicaHy Hberates hydrogen chloride that can corrode storage containers and commercial metal-cleaning equipment. The Hberated hydrogen chloride can be neutralized by an appropriate epoxide to form noncorrosive chlorohydrins (qv). 

The higher the content of melamine, the higher is the stability of the hardened resin against the influence of humidity and water (hydrolysis resistance) [17, 45,46]. Resins containing melamine can be characterized by the molar ratio F (NH2)i or by the triple molar ratio F U M. The mass portion of melamine in the resin can be described as being based on the liquid resin or based on the total mass of urea and melamine in the resin (Table 6). MUF-resin hardener addition usually is distinctly higher than in UF-resins. 

Technology Description Hydrolysis is the process of breaking a bond in a molecule (which is ordinarily not water-soluble) so that it will go into ionic solution with water. Hydrolysis can be achieved by the addition of chemicals (e.g., acid hydrolysis), by irradiation (e.g., photolysis) or by biological action (e.g., enzymatic bond cleavage). The cloven molecule can then be further treated by other means to reduce toxicity. 

Important properties of phenolic resins are their hardness, corrosion resistance, rigidity, and resistance to water hydrolysis. They are also less expensive than many other polymers. 

Imine formation is reversible. Show all the steps involved in the acid-catalyzed reaction of an imine with water (hydrolysis) to yield an aldehyde or ketone plus primary amine. 

The most common reactions of carboxylic acid derivatives are substitution by water (hydrolysis) to yield an acid, by an alcohol (alcoholysis) to yield an ester, by an amine (aminolysis) to yield an amide, by hydride ion to yield an alcohol (reduction), and by an organometallic reagent to yield an alcohol (Grignard reaction). 

Special attention is directed to those instances in which the rate of reaction is apparently independent of the concentration of one of the reactants, even though this reactant is consumed during the reaction. For example, in the reaction between an ester and water (hydrolysis) in a predominantly aqueous environment, the theoretical rate expression for the ester can be written in terms of the concentrations of the ester (Ce) and water (CV) ... 

When the drug is nonionizable in water, three hydrolytic pathways are available [Eq. (33)] it can degrade by specific acid catalysis represented by the first kinetic term in Eq. (33), water hydrolysis (second term), and specific base catalysis (third term) ... 

During the past 30 years, there have been significant developments of parenteral disperse formulations. The use of parenteral emulsions can overcome the problems of low aqueous solubility and water hydrolysis of many drugs [184, 185]. Such formulations can avoid the use of conventional co-solvent systems and the undesirable effects caused by precipitation of drugs at the injection site. Recent developments of parenteral disperse formulations have the potential to provide sustained release and targeting of drugs [186-189],... 

As is apparent from Fig. 1, the dianions of monoalkyl phosphates normally resist hydrolysis. However, for leaving groups whose conjugate acids exhibit a pKa < 5 in water, hydrolysis of the dianion becomes faster than that of the monoanion. Fig. 2 shows a pH profile characteristic of this situation. Whereas the hydrolysis rate of 2,4,6-trichlorophenyl phosphate (pKa of the phenol 6.1) still shows the typical monoanion preference as seen for methyl phosphates (Fig. 1), the dianion of 2,4-dinitrophenyl phosphate (pKa of the phenol 4.09) is hydrolyzed far faster than the monoanion 2-chloro-4-nitrophenyl phosphate represents an intermediate case (pKa of the phenol 5.45)6S). 

The anhydrous bromide should be destroyed by melting and pouring slowly into running water. Hydrolysis is very violent and may destroy the container if water is added to it. 

The solution of a salt derived from a strong base and weak acid is basic because the anion of a weak acid reacts with water (hydrolysis) to form hydroxide ions. Consider the soluble salt NaCIO found in chlorine bleaches prepared by reacting NaOH, a strong base, and HC10, a weak acid. The salt dissociates completely in water and the conjugate base of the weak acid, CIO-, hydrolyzes, producing OH- ions. 

In order to balance the chemistry of water hydrolysis, one should invoke the formation of 1 mol of HBr. The HBr thus formed would react either with the organometallic species to produce more of the tetrafluoroethyl ether by-product and zinc bromide, or with zinc metal to form zinc bromide and hydrogen gas. 

Wastewater treatment facilities, industrial hygiene at, 14 213 Wastewater treatment sludge as biomass, 3 684 Waste zero system, 14 110 Water, 26 1-50. See also Dessicants, Drinking water Hydrolysis Liquid water Oxide-water interfaces Seawater Sodium chloride-water system Wastewater Wastewater entries, Ice... 

Dissolving or swelling of crude Copper Phthalocyanine Blue in sulfuric acid, followed by precipitation in water (hydrolysis) affords the a-modification with a fine particle size. Emulsifiers may be present if desired. Dry milling of the crude (3-crys-tal phase, for instance in the presence of sodium chloride or sodium sulfate, also yields the a-phase. 

Di-isopropyl phosphorofluoridate is a practically odourless, mobile liquid, b.p. 183°/760 mm. (by extrapolation), f.p. ca. -82°. This wide range of temperature over which the compound is liquid adds to its usefulness. A specimen of the pure liquid has remained unchanged in a glass vessel for several years. Whereas the phosphorochloridate was readily hydrolysed by water, hydrolysis of the phosphorofluoridate was slow and took 72 hr. for completion at 15° and then only in the presence of a large excess of water (1 per cent solution solubility 1-5 per cent) P(OPr<)2 of+hso - P(OPrf)2 oh + hf. 

The unequal basicities of the three nitranilines can be illustrated by the following experiment. It is a general property of the salts of weak bases—as well as of weak acids—that in aqueous solution they are stable only if an excess of acid (or alkali) is present. When such solutions are diluted with water hydrolysis occurs as a result of the operation of the law of mass action. In the present case this phenomenon shows itself in the appearance of the yellow colour characteristic of the bases and finally, since the nitranilines are sparingly soluble in water, in their precipitation in crystalline form. The weaker the base the smaller is the amount of water which must be added in order to make the hydrolysis perceptible. 

WHEAT WMDM WPMD water hydrolysis of explosives and agent technology WHEAT multipurpose demilitarization machine WHEAT projectile/mortar disassembly (machine)... 

In clear and muddy waters, hydrolysis half-lives were 18->50 and 10-25 d, respectively, (Nesbitt and Watson, 1980). 

For computer calculations. The value of is the expected distilled water hydrolysis rate constant at this pH. 

The alcoholysis rate decreases by either increasing the steric bulk of the alcohol or decreasing its nucleophUicity (i.e., MeOH > EtOH > PrOH > BuOH 2,2,2-tri-fluoroethanol). Parallel to the decrease of the chain-transfer rate, the molecular weight of the copolymer increases. An effective role of water as hydrolysis agent in alcoholic media appears very unlikely as HOOC-terminated polyketone or oligo-ketone have never been observed. Obviously, in neat water, hydrolysis is a feasible chain-transfer path, leading to acid-terminated materials [13]. 

Both acyl halides and anhydrides react with water (hydrolysis). Acyl halides react to form one mole of the carboxylic acid and one mole of the hydrohalic acid, HX. Anhydrides react to form two moles of carboxylic acid. 

Water treatment by either direct or contact filtration has become common practice for raw water with low turbidity [<3NTU] and low colour. Simple metal salts such as alum or ferric chloride are added to plant inlet water. Hydrolysis takes place with the formation of hydroxylated species, which adsorb, reducing or neutralizing the charge on the colloidal particles in the raw water, promoting their collision and the formation of floes that settle or can be filtered out. 

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