Hydrolysis The reaction of a substance with water

Hydrolysis. The reaction of a substance with water a metathetical reaction involving water and producing substances containing fragments of the water molecule in their composition. 

Solvolysis is the reaction of a substance with the solvent in which it is dissolved. The solvolysis reactions that we will consider in this chapter occur in aqueous solutions so they are called hydrolysis reactions. Hydrolysis is the reaction of a substance with water. Some hydrolysis reactions involve reaction with H3O+ or OH ions. One common kind of hydrolysis involves reaction of the anion of a weak add with water to form nonionized acid molecules and OH ions. This upsets the H30 /0H balance in water and produces basic solutions. This reaction is usually represented as... 

Hydrolysis. The chemical reaction of a substance with water to form one or more new substances. Examples of hydrolysis are the catalytic conversion of starch into glucose the catalytic or enzymatic conversion of sucrose into glucose and fructose the conversion of natural fats into fatty acids and glycerin... 

Hydrolysis is the reaction of a compound with the elements of water whereby decomposition of the substance occurs. The reaction produces one or more new substances. 

To ascertain whether tritium could have entered the polyisobutylenes by a process other than the hydrolysis of a carbon-aluminium bond, we tested the reaction of suitable polymers with aluminium bromide. The polyisobutylenes were dissolved in ethyl bromide, and phials of aluminium bromide were crushed into these solutions, which were subsequently kept at 0 °C for ca. 15 minutes, and then hydrolysed in the usual way with tritiated water. The three substances examined in this way were polyisobutylenes of high and low DP, and nonadecane. The polyisobutylenes contain approximately one double bond per molecule. The results in... 

It is significant that the most effective volatile corrosion inhibitors are the products of the reaction of a weak volatile base with a weak volatile acid. Such substances, although ionized in aqueous solutions, undergo substantial hydrolysis (reaction with water), the extent of... 

The hydrolysis of amides and nitriles may be conducted not only in acid solution but also in the presence of alkali. When dealing with substances soluble in water only with difficulty, it is customary to use alcohol as a solvent. In the latter instance, in connection with acid hydrolysis, the organic acid formed in the reaction is partially converted into an ester, whereas ammonia, or a substituted ammonia, will be present in the form of a salt with the inorganic acid used. When the hydrolysis is conducted in the presence of alkali, the organic acid is present as the sodium or potassium salt, whereas the amine is liberated and, if volatile, may be lost when the reaction mixture is refluxed. Type experiments are illustrated in connection with the laboratory work, page 146. 

Example CH3CH=CH2 + HC1 - CH3CHC1CH3. hydrolysis reaction The reaction of water with a substance, resulting in the formation of a nev element-oxygen bond. Example PCl5(s) +... 

After isolation, the intermediate products were reacted with zinc in acetonitrile or a glyme solvent to provide the trifluorovinyl ether monomers. This reaction with zinc is also sensitive to the presence of protic substances in the reaction mixture, and forms the same tetrafluoroethyl ether by-product in an undesirable side reaction. The reaction of the 2-bromotetrafluoroethyl ether reactants with zinc involves the formation of zinc organometallic species as an intermediate, and this species is sensitive to hydrolysis by water or acidic substances (Figure 3.6). 

Hydrogenation reaction in which hydrogen is added to unsaturated organic compounds in presence of a catalyst, used to turn liquid vegetable oils into solids Hydrolysis decomposition or change of a substance by its reaction with water Hydronium the H3O+ ion Hydrosphere the sum total of Earth s water including the oceans, polar ice caps, groundwater, atmospheric water, rivers, and lakes... 

Preparation from Borax. Dissolve 12 g of borax in 25 ml of water in a beaker with heating. What is the reaction of the solution to litmus and what is it due to Write the molecular and net-ionic equations of the borax hydrolysis reaction. How can the hydrolysis of borax be facilitated Calculate what amount of a 25% hydrochloric acid solution is needed to prepare boric acid from 12 g of borax. Measure off the calculated amount of acid, and taking a small excess amount, pour the acid into the hot borax solution. Let the solution cool slowly. What substance crystallizes Filter off the crystals on a Buchner funnel, dry them between filter paper sheets, and recrystallize them from hot water, guiding yourself by the table of solubilities. Determine the product yield (in per cent). Keep the prepared boric acid for the following experiments. 

Fontes et al. (1998b) studied the enantioselectivity of cutinase and found that it was very selective toward one enantiomer with an enantiomeric excess of almost 100%. They found that the enantioselectivity was very sensitive to changes in water content. Bornscheuer et al. (1992) studied hydrolysis, esterification, and transesterification in carbon dioxide to try to find the best method for producing enantiomerically pure substances in carbon dioxide. They found that the thermodynamically favored hydrolysis led to higher enantiomeric excess with less enzyme in the shortest time. Michor et al. (1996b) also examined more than one system to determine a better route to product and found that while the transesterification of -menthol was fast and resulted in high enantiomeric excess, resolution of -citronellol was not feasible. The reaction rate for the reaction of -citronellol was 10-20 times of that of -menthol, but was not selective. 

The first observation of the instability of carbohydrate orthoesters toward alkali came from Haworth, Hirst and Miller in connection with their experiments on the simultaneous deacetylation and methylation of L-rhamnose methyl 1,2-orthoacetate. These authors noticed that methylation by methyl iodide and silver oxide in the presence of solid sodium hydroxide resulted in the formation of crystalline methyl tri-methyl-/3-L-rhamnopyranoside. A similar result was obtained by Bott, Haworth and Hirst on the simultaneous deacetylation and methylation of triacetyl-D-mannose methyl 1,2-orthoacetate by the use of excessive quantities of dimethyl sulfate and alkali. The reaction produced a mixture of a. and /3 forms of methyl tetramethyl-D-mannopyranoside but the yield was only 40%. When the acetylated orthoester was submitted to methylation with silver oxide and methyl iodide in the presence of sodium hydroxide, the product was mainly trimethyl-rhamnose methyl 1,2-orthoacetate. This result indicates that for the alkaline hydrolysis of orthoesters, hydroxyl ions are necessary. Such ions are present in the dimethyl sulfate-alkali process, but are absent in the methyl iodide treatment except when the reaction mixture contains a little water either by accident or from the decomposition of the sugar molecule. Haworth, Hirst and Samuels examined the behavior of dimethyl-L-rhamnose methyl 1,2-orthoacetate in alkaline solution. When the substance was heated under various conditions with 0.1 A alkali at 70 there was no appreciable hydrolysis at the end of ninety minutes, whereas at 80 for... 

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