Acid chloride reaction with water

Organic Chlorides/Halides — Several organic compounds also are hydrolyzed (or react with water) to produce corrosive materials. Notable inclusions among these compounds are acetic anhydride ([CH3COJ2O), and acetyl chloride (CH3COCI), both of which produce acetic acid upon reaction with water. Both acetic anhydride and acetyl chloride are corrosive in addition, mixtures of the vapors of acetic anhydride and acetic acid are flammable in air, and acetyl chloride itself is flammable. 

Conversion of Acid Halides into Acids Hydrolysis Acid chlorides react with water to yield carboxylic acids. This hydrolysis reaction is a typical nucleophilic acyl substitution process and is initiated by attack of water on the acid chloride carbonyl group. The tetrahedral intermediate undergoes elimination of Cl and loss of H+ fo give the product carboxylic acid plus HC1. 

The source of alcohol 50 is most probably acid-catalysed hydrolysis of 49 to the nitrosocarbonylbenzene intermediates 51, which, like acid chlorides, react with water to give benzoic acids 52 (Scheme 1 pathway (i)).159 Acylnitroso intermediates 51 were trapped as the Diels Alder adducts 53 in reactions in CH3CN/H20 and in the presence of cyclopentadiene. In CH3CN/10% H280, 53 was enriched in lsO... 

Now let s draw the forward scheme. Hydrolysis of the nitrile to the carboxylic acid, followed by reaction with thionyl chloride, produces the acid chloride. Reaction with excess methyl magnesium bromide, followed by water work-up, results in the formation of a tertiary alcohol, with the incorporation of two new methyl groups. The tertiary alcohol can then serve as a nucleophile in an acetylation reaction (upon treatment with acetyl chloride) to give the desired ester. 

Reactions of Aspirin, (i) Distinction from Salicylic acid. Shake up with water in two clean test-tubes a few crystals of a) salicylic acid, (0) aspirin, a very dilute aqueous solution of each substance being thus obtained. Note that the addition of i drop of ferric chloride solution to (a) gives an immediate purple coloration, due to the free —OH group, whereas (b) gives no coloration if the aspirin is pure. 

After all the diethyl sulphate has been introduced, reflux the mixture gently for 2 hours with stirring. Transfer the diluted reaction mixture to a separatory funnel, run oflF the lower aqueous layer, wash successively with water, dilute sulphuric acid (twice), and with water until the washings are neutral to litmus. Dry over anhydrous calcium chloride or magnesium sulphate, and distil. Collect the phenyl ethyl ether (a colourless liquid) at 168-170°. The yield is 50 g. 

Hydrolysis (Section 20 4) Acyl chlorides react with water to yield carboxylic acids In base the acid is converted to its carbox ylate salt The reaction has little prepara tive value because the acyl chloride is nearly always prepared from the carboxyl ic acid rather than vice versa... 

The important chemical properties of acetyl chloride, CH COCl, were described ia the 1850s (10). Acetyl chloride was prepared by distilling a mixture of anhydrous sodium acetate [127-09-3J, C2H202Na, and phosphorous oxychloride [10025-87-3] POCl, and used it to interact with acetic acid yielding acetic anhydride. Acetyl chloride s violent reaction with water has been used to model Hquid-phase reactions. 

Because almost any diacid can be leaddy converted to the acid chloride, this reaction is quite versatile and several variations have been developed. In the interfacial polymerization method the reaction occurs at the boundary of two phases one contains a solution of the acid chloride in a water-immiscible solvent and the other is a solution of the diamine in water with an inorganic base and a surfactant (48). In the solution method, only one phase is present, which contains a solution of the diamine and diacid chloride. An organic base is added as an acceptor for the hydrogen chloride produced in the reaction (49). Following any of these methods of preparation, the polymer is exposed to water and the acid chloride end is converted to a carboxyhc acid end. However, it is very difficult to remove all traces of chloride from the polymer, even with repeated washings with a strong base. 

At 180°C, reaction with water results in formic acid, methyl chloride, methanol, hydrochloric acid, and some carbon monoxide. 

Chemical Reactivity - Reactivity with Water. Reacts violently with water, liberating hydrogen chloride gas and heat Reactivity with Common Materials None if dry. If wet it attacks metals because of hydrochloric acid formed flammable hydrogen is formed Stability During Transport Stable if kept dry and protected from atmospheric moisture Neutralizing Agents for Acids and Caustics Hydrochloric acid formed by reaction with water can be flushed away with water. Rinse with sodium bicarbonate or lime solution Polymerization Not pertinent Inhibitor of Polymerization Not pertinent. 

The acid chloride reacts with the free hydroxylamine with considerable rapidity apparently without dissolving. The reaction is completed when a sample of the suspension shows to become clear on adding aqueous alkali. The crystalline pale-yellow mass of product Is separated by filtering, lavishly washed with water and dried in vacuum. The crude product yield is actually quantitative. The product is purified with excellent yields by repeatedly crystallizing from hot dioxane and washing with ether melting point 181°C to 182°C (dec.). 

Conversion of Acid Halides into Esters Alcoholysis Acid chlorides react with alcohols to yield esters in a process analogous to their reaction with water to yield acids. In fact, this reaction is probably the most common method for preparing esters in the laboratory. As with hydrolysis, alcoholysis reactions are usually carried out in the presence of pyridine or NaOH to react with the HC1 formed. 

The chemistry of acid anhydrides is similar to that of acid chlorides. Although anhydrides react more slowly than acid chlorides, the kinds of reactions the two groups undergo are the same. Thus, acid anhydrides react with water to form acids, with alcohols to form esters, with amines to form amides, and with UAIH4 to form primary alcohols. Only the ester and amide forming reactions are much used, however. 

The equations that represent the reactions with water support the prediction that NH4NO3 dissolves to form an acidic solution and Na3P04 dissolves to form a basic solution. Calcium chloride is the salt of a strong base-strong acid, so neither ion reacts with water and the solution is neutral. Both ions in ammonium hydrogen carbonate react with water. Because Kt, for HCOs" is greater than for NH4, the salt dissolves to form a weakly basic solution. 

When heated in air at 800°C AS4S4 vapors begin to dissociate to AS2S2 which then ignites to form arsenic oxides. Ignition in chlorine produces arsenic chloride. Reaction with fluorine forms arsenic trifluoride. It is stable in water and also in the air at ambient temperatures. It does not react with hot concentrated HCl but is decomposed by nitric acid. It forms thioarsenite ion, AsS3 and elemental arsenic when warmed with caustic soda solution. Similar reaction occurs with sodium sulfide. 

Hexammino-chromic Bromide, [Cr(NH i)(i]Or3, is precipitated from a concentrated solution of the nitrate of the series by decomposing it with concentrated hydrobromic acid. The orange-yellow plates which separate are decanted from the solution, washed with dilute hydrobromic acid and then with water. It is easily soluble in pure water but sparingly so in presence of hydrobromic acid. The transformation of the salt into bromo-pentammino-chromic bromide on heating with acid takes place more slowly than the analogous reaction with the chloride of the series. 

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