Ethers, Anhydrides, and Esters

Take the receiver from the immediate vicinity of any flames, and transfer the contents to a separatory funnel. Shake the ether 

Draw off the lower aqueous layer, which should still be alkaline, add to the ether about one-fifth its volume of a cold mixture of equal volumes of concentrated sulphuric acid and water. Shake thoroughly, let the mixture stand until the two layers become clear. Draw off the acid layer and run the ether into a distilling 

1 If a dropping funnel is not available or if the tube of the funnel is not long enough, arrange the apparatus as described in 40, page 28. 

Ether boils at 35°. Write equations for the reactions which take place when alcohol is treated with sulphuric acid, and when the product of this reaction is heated with alcohol at about 140°. What would happen if in the experiment the temperature were allowed to rise as high as 180°  

—(a) The ether is shaken with a solution of sodium hydroxide to remove the sulphur dioxide formed as a result of the reduction of the sulphuric acid by the alcohol or by the carbon that separates. The treatment with sulphuric acid removes the alcohol and nearly all the water. The method outlined above can be carried out more rapidly than the one commonly used, namely shaking with a solution of calcium chloride to remove alcohol and then drying first with anhydrous calcium chloride and then with sodium. 

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Comp.ne the ai tion of caustic tdkalis on ethers, esters and anhydrides. 

Ethers, esters, and anhydrides dissolve in cold concentrated sulphuric acid. When the solutions are poured on ice the ethers and esters are recovered unchanged the anhydrides are rapidly hydrolyzed. If the mixtures are heated and then poured into water ethers and esters yield alkyl sulphuric acids ... 

Compare the action of the following reagents on ethers, esters, and anhydrides (a) water, ( ) sodium hydroxide, (c) chlorine, (d) ammonia. 

It is convenient to consider the indiflferent or neutral oxygen derivatives of the hydrocarbons—(a) aldehydes and kelones, (b) esters and anhydrides, (c) alcohols and ethers—together. All of these, with the exception of the water-soluble members of low molecular weight, are soluble only in concentrated sulphuric acid, i.e., fall into Solubility Group V. The above classes of compounds must be tested for in the order in which they are listed, otherwise erroneous conclusions may be drawn from the reactions for functional groups about to be described. 

The production of both an alcohol and the sodium salt of an acid might easily be confused with the hydrolysis products of an ester (in the above instance benzyl benzoate). Such an error would soon be discovered (e.g., by reference to the b.p. and other physical properties), but it would lead to an unnecessary expenditure of time and energy. The above example, however, emphasises the importance of conducting the class reactions of neutral oxygen-containing compounds in the proper order, viz., (1) aldehydes and ketones, (2) esters and anhydrides, (3) alcohols, and (4) ethers. 

Cationic copolymerization of cyclic ethers, formals, esters and anhydrides has been thoroughly studied in recent years and sufficient information about it is now available. The propagating species involved in the cationic copolymerization of these oxacyclic monomers are believed to be the oxonium ions in most cases, but their detailed nature is dependent on monomer structure. From their copolymerization behavior, these monomers can be arranged in the following order of increasing car-bocationic character of the propagating species ... 

If the unknown, neutral, oxygen-containing compound does not give the class reactions for aldehydes, ketones, esters and anhydrides, it is probably either an alcohol or an ether. Alcohols are readily identified by the intense characteristic hydroxyl adsorption which occurs as a broad band in the infrared spectrum at 3600-3300 cm-1 (O—H str.). In the nuclear magnetic resonance spectrum, the adsorption by the proton in the hydroxyl group gives rise to a broad peak the chemical shift of which is rather variable the peak disappears on deuteration. 

The copolymerization between trioxane and suitable comonomers (ethylene oxide, 1,3-dioxolane, diethylene glycol formal, 1,4-butane diol formal in amounts of 2-5% by weight) is performed using cationic initiators. The cationic initiators could be Lewis acids, such as BF3 or its etherate BF3Bu20 which was used, for example by Celanese (the mechanism of this reaction was studied in detail [163,164]) or protic acids such as perchloric acid, perfluoroalkane sulfonic acids and their esters and anhydrides. Heteropoly acids were used and also a series of carbenium, oxocarbenium salts, onium compounds, and metal chelates. To regulate the molecular weight chain-transfer agents, such as methylal and butylal, are added. 

The discovery of lithium aluminum hydride and similar compounds has made possible the direct reduction of the carboxyl group. Acid chlorides, esters, and anhydrides are similarly reduced to primary alcohols. Lactones are converted to diols." The reaction takes place readily at room temperature. The compound to be reduced is added to an ethereal solution of the reagent, and the resulting alcoholate is hydrolyzed by acid. 

The carbonium ion abstracts a tertiary hydrogen from the isoparaffin, yielding a hexyl ion which then abstracts a hydride ion from the unrearranged isoparaffin, saturates itself, and starts a new cycle. Carbonium ions are formed when unsaturated compounds are dissolved in proton acids or, in general, if the compound is sufficiently basic relative to the acid, i.e., alcohols, ethers, esters, acid anhydrides, alkyl-substituted aromatic compounds will form carbonium ions in sulfuric, hydrofluoric, and other acid solvents. 

O-C bonds in acids, esters and anhydride Table 6.3.3 O-C BDEs in Acids, Ethers and Anhydrides es ... 

Precaution Combustible incompat. with oxidizing agents, acid chlorides, acid anhydrides forms ethers, esters, and salts with metals and amines keep away from food Hazardous Decomp. Prods. Heated to decomp., emits toxic fumes of chlorine, CO, CO2, hydrogen chloride gas emits toxic fumes underfire conditions... 

Almost insoluble in cold water. Higher alcohols (including benzyl alcohol), higher phenols (e.g., naphthols), metaformaldehyde, paraldehyde, aromatic aldehydes, higher ketones (including acetophenone), aromatic acids, most esters, ethers, oxamide and domatic amides, sulphonamides, aromatic imides, aromatic nitriles, aromatic acid anhydrides, aromatic acid chlorides, sulphonyl chlorides, starch, aromatic amines, anilides, tyrosine, cystine, nitrocompounds, uric acid, halogeno-hydrocarbons, hydrocarbons. 

Diester/Ether Diol of Tetrabromophthalic Anhydride. This material [77098-07-8] is prepared from TBPA in a two-step reaction. First TBPA reacts with diethylene glycol to produce an acid ester. The acid ester and propylene oxide then react to give a diester. The final product, a triol having two primary and one secondary hydroxyl group, is used exclusively as a flame retardant for rigid polyurethane foam (53,54). 

Chemical Properties. A combination of excellent chemical and mechanical properties at elevated temperatures result in high performance service in the chemical processing industry. Teflon PEA resins have been exposed to a variety of organic and inorganic compounds commonly encountered in chemical service (26). They are not attacked by inorganic acids, bases, halogens, metal salt solutions, organic acids, and anhydrides. Aromatic and ahphatic hydrocarbons, alcohols, aldehydes, ketones, ethers, amines, esters, chlorinated compounds, and other polymer solvents have Httle effect. However, like other perfluorinated polymers,they react with alkah metals and elemental fluorine. 

Ahyl alcohol undergoes reactions typical of saturated, aUphatic alcohols. Ahyl compounds derived from ahyl alcohol and used industriahy, are widely manufactured by these reactions. For example, reactions of ahyl alcohol with acid anhydrides, esters, and acid chlorides yield ahyl esters, such as diahyl phthalates and ahyl methacrylate reaction with chloroformate yields carbonates, such as diethylene glycol bis(ahyl carbonate) addition of ahyl alcohol to epoxy groups yields products used to produce ahyl glycidyl ether (33,34). 

Ethers. In the presence of anhydrous agents such as ferric chloride (88), hydrogen bromide, and acid chlorides, ethers react to form esters (see Ethers). Esters can also be prepared from ethers by an oxidative process (89). With mixed sulfonic—carboxyhc anhydrides, ethers are converted to a mixture of the corresponding carboxylate and sulfonate esters (90) ... 

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