Acids mineral, reaction with alcohols

Reactions with Alcohols, Mercaptans, and Phenols. Alcohols add readily to acetaldehyde in the presence of trace quantities of mineral acid to form acetals eg, ethanol and acetaldehyde form diethyl acetal [105-57-7] (65). Similarly, cycHc acetals are formed by reactions with glycols and other polyhydroxy compounds eg, ethylene glycol [107-21-1] and acetaldehyde give 2-methyl-1,3-dioxolane [497-26-7] (66) ... 

Formic acid forms esters with primary, secondary, and tertiary alcohols. The high acidity of formic acid makes use of the usual mineral acid catalysts unnecessary in simple esterifications (17). Formic acid reacts with most amines to form formylamino compounds. With certain diamines imida2ole formation occurs, a reaction that has synthetic utiHty (18) ... 

Protonolysis. Simple trialkylboranes are resistant to protonolysis by alcohols, water, aqueous bases, and mineral acids. In contrast, carboxyUc acids react readily with trialkylboranes, removing the first alkyl group at room temperature and the third one at elevated temperatures. Acetic and propionic acids are most often used. The reaction proceeds with retention of configuration of the alkyl group via a cycHc, six-membered transition state (206). 

The newer HFC refrigerants are not soluble in or miscible with mineral oils or alkylbenzenes. The leading candidates for use with HFC refrigerants are polyol ester lubricants. These lubricants are derived from a reaction between an alcohol and a normal or branched carboxyflc acid. The most common alcohols used are pentaerythritol, trimethylolpropane, neopentjlglycol, and glycerol. The acids are usually selected to give the correct viscosity and fluidity at low temperatures. 

Reactions. Saligenin [90-01-7] undergoes the typical reactions of phenols and benzyl alcohol. When heated above 100°C, it transforms into a pale yellow resinous material. Amorphous condensation products are obtained when saligenin reacts with acetic anhydride, phosphoms pentachloride, or mineral acids. Upon boiling with dilute acids, saligenin is converted into a resinous body, saliretin, a condensed form of saligenin. Condensation reactions of saligenin with itself in the absence of any catalysts and in the presence of bases have also been studied. 

Manufacture. PVBs are manufactured by a variety of two-stage heterogeneous processes. In one of these an alcohol solution of poly(vinyl acetate) and an acid catalyst are heated to 60—80°C with strong agitation. As the poly(vinyl alcohol) forms, it precipitates from solution (77). Ethyl acetate, the principle by-product, is stripped off and sold. The precipitated poly(vinyl alcohol) is washed to remove by-products and excess acid. The poly(vinyl alcohol) is then suspended in a mixture of ethyl alcohol, butyraldehyde, and mineral acid at temperatures above 70°C. As the reaction approaches completion the reactants go into solution. When the reaction is complete, the catalyst is neutralized and the PVB is precipitated from solution with water, washed, centrifuged, and dried. Resin from this process has very low residual vinyl acetate and very low levels of gel from intermolecular acetalization. 

Aziridinones undergo two types of selective ring opening by nucleophiles <68AG(E)25). Reaction with proton-containing nucleophiles, e.g. water, alcohols, thiols, amines and mineral acids, leads exclusively to amides (339), corresponding to an C —N bond rupture. 

The nitrile may best be saponified with methyl alcoholic potash while heating to 190° to 200°C with application of pressure. After the methyl alcohol has evaporated the salt is introduced into water and by the addition of dilute mineral acid until the alkaline reaction to phenolphthalein has just disappeared, the amphoteric 1-methyl-4-phenyl-piperidine-4-carbOxylic acid is precipitated while hot in the form of a colorless, coarsely crystalline powder. When dried On the water bath the acid still contains 1 mol of crystal water which is lost only at a raised temperature. The acid melts at 299°C. Reaction with ethanol yields the ester melting at 30°C and subsequent reaction with HCI gives the hydrochloride melting at 187° to 188°C. 

The R61e of the Sulphuric Acid.—If acetic acid and alcohol alone are heated together no noticeable reaction takes place even after a long time. The reaction is only started by added sulphuric acid, which may be replaced by gaseous hydrogen chloride. In all probability these mineral acids form an unstable addition compound (more likely with the acetic acid) and this compound reacts with alcohol to... 

Reacts slowly with alcohols forming acetate esters (Morrison and Boyd, 1971). This reaction may be promoted by the presence of mineral acids such as sulfuric acid. 

Primary aromatic amines on reaction with nitrous acid in the presence of hydrochloric acid (or other mineral acid) at about 0 °C yield diazonium salts as discrete intermediates. The diazonium salts similarly derived from aliphatic primary amines decompose readily even at this temperature to yield the corresponding alcohol (and other products) with the evolution of nitrogen. 

Friedel-Crafts reactions can also be done with alcohols in the presence of mineral acid. The acid leads to the elimination of water from the alcohol resulting in the formation of an alkene that can then be converted to a carbocation ... 

Lignified tissues give color reactions with several alcohols and ketones in the presence of small amounts of mineral acids (Brauns 1952). For example, methanol- or acetone-hydrochloric acid forms a red color on contact with spruce wood amyl alcohol-sulfuric acid gives a blue color and methylheptenone, (CH3)2C=CHCH2CH2COCH3, a purple-red color when applied to spruce wood. 

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