Of strong acids

Toluene-/ sulplionamide is almost insolubb in cold water, but dissolves readily in sodium hydroxide solution (as the sodium derivative) aid is immediately reprecipitated on the addition of strong acids. To show the formation of the sodium derivative, dissolve about o-2 g. of metallic sodium in about 10 ml, of ethanol, cool the solution, and then add it to a solution of 1 g. of the sulphonamide in 20 ml. of cold edianol. On shaking the mixture, fine white crystals of the sodium derivative, CH,C,HjSO,NHNa, rapidly separate, and may be obtained pure by filtering at the pump, and washing firet with a few ml. of ethanol, and then with ether. 

The aniline then reacts with the ap-unsaturated aldehyde by 1 4-addition the addition product, under the influence of strong acid, cyclises to form 1 2-dihydroquinaldine. The latter is dehydrogenated by the condensation products of aniline with acetaldehyde and with crotonaldehyde simultaneously produced ( .c., ethylideneaniline and crotonylideneaniline) these anils act as hydrogen acceptors and are thereby converted into ethylaniline and n-butyl-aniline respectively. 

Nitration in organic solvents is strongly catalysed by small concentrations of strong acids typically a concentration of io mol 1 of sulphuric acid doubles the rate of reaction. Reaction under zeroth-order conditions is accelerated without disturbing the kinetic form, even under the influence of very strong catalysis. The effect of sulphuric acid on the nitration of benzene in nitromethane is tabulated in table 3.3. The catalysis is linear in the concentration of sulphuric acid. 

Nitration in the presence of strong acids or Lewis acids Solutions of dinitrogen pentoxide in sulphuric acid nitrate 1,3-dimethyl-benzene-4,6-disulphonic acid twice as fast as a solution of the same molar concentration of nitric acid. This is consistent with Raman spectroscopic and cryoscopic data, which establish the following ionisation ... 

The nitration of sensitive compounds with dinitrogen pentoxide has the advantage of avoiding the use of strong acids or aqueous conditions this has been exploited in the nitration of benzylidyne trichloride and benzoyl chloride, which reacted in carbon tetrachloride smoothly and without hydrolysis. 

CHjCiMeljCHjCO-U.sed as indicators in the titration of strong acids or strong bases... 

Ester hydrolysis is the most studied and best understood of all nucleophilic acyl sub stitutions Esters are fairly stable in neutral aqueous media but are cleaved when heated with water m the presence of strong acids or bases The hydrolysis of esters m dilute aqueous acid is the reverse of the Eischer esterification (Sections 15 8 and 19 14)... 

Amides are the least reactive caiboxyhc acid deiivative and the only nucleophilic acyl substitution reaction they undeigo is hydrolysis Amides are fanly stable m water but the amide bond is cleaved on heating m the presence of strong acids 01 bases Nomi nally this cleavage produces an amine and a caiboxyhc acid... 

Deprotection by this method rests on the ease with which benzyl esters are cleaved by nucleophilic attack at the benzylic carbon m the presence of strong acids Bromide ion IS the nucleophile... 

Selected Primary Standards for the Standardization of Strong Acid and Strong Base Titrants... 

Consider, for example, a mixture of OH and. The volume of strong acid... 

The acidity of a water sample is determined by titrating to fixed end points of 3.7 and 8.3, with the former providing a measure of the concentration of strong acid, and the latter a measure of the combined concentrations of strong acid and weak acid. Sketch a titration curve for a mixture of 0.10 M HCl and 0.10 M H2CO3 with 0.20 M strong base, and use it to justify the choice of these end points. 

Compare this equation with the relationship between the moles of strong acid, N, titrated with a strong base of known concentration. 

Directions are provided for the quantitative analyses of Ck and P04 , and for conducting titrations of strong acids and strong bases. 

Furfural can be classified as a reactive solvent. It resiniftes in the presence of strong acid the reaction is accelerated by heat. Furfural is an excellent solvent for many organic materials, especially resins and polymers. On catalyzation and curing of such a solution, a hard rigid matrix results, which does not soften on heating and is not affected by most solvents and corrosive chemicals. 

Furfural is a resin former under the influence of strong acid. It will self-resinify as well as form copolymer resins with furfuryl alcohol, phenoHc compounds, or convertible resins of these. Conditions of polymerization, whether aqueous or anhydrous, inert or oxygen atmosphere, all affect the composition of the polymer. Numerous patents have issued relating to polymerization and to appHcations. Although the resins exhibit a degree of britdeness, they have many outstanding properties a number of appHcations are discussed under "Uses."... 

Unsaturated aldehydes undergo a similar reaction in the presence of strongly acid ion-exchange resins to produce alkenyUdene diacetates. Thus acrolein [107-02-8] or methacrolein [78-85-3] react with equimolar amounts of anhydride at —10°C to give high yields of the -diacetates from acetic anhydride, useful for soap fragrances. 

Although acetyl chloride is a convenient reagent for deterrnination of hydroxyl groups, spectroscopic methods have largely replaced this appHcation in organic chemical analysis. Acetyl chloride does form derivatives of phenols, uncompHcated by the presence of strong acid catalysts, however, and it finds some use in acetylating primary and secondary amines. 

Esters. Most acryhc acid is used in the form of its methyl, ethyl, and butyl esters. Specialty monomeric esters with a hydroxyl, amino, or other functional group are used to provide adhesion, latent cross-linking capabihty, or different solubihty characteristics. The principal routes to esters are direct esterification with alcohols in the presence of a strong acid catalyst such as sulfuric acid, a soluble sulfonic acid, or sulfonic acid resins addition to alkylene oxides to give hydroxyalkyl acryhc esters and addition to the double bond of olefins in the presence of strong acid catalyst (19,20) to give ethyl or secondary alkyl acrylates. 

In general, the reactions of the perfluoro acids are similar to those of the hydrocarbon acids. Salts are formed with the ease expected of strong acids. The metal salts are all water soluble and much more soluble in organic solvents than the salts of the corresponding hydrocarbon acids. Esterification takes place readily with primary and secondary alcohols. Acid anhydrides can be prepared by distillation of the acids from phosphoms pentoxide. The amides are readily prepared by the ammonolysis of the acid haUdes, anhydrides, or esters and can be dehydrated to the corresponding nitriles (31). 

The first member of the series, CF SO H, has been extensively studied. Trifluoromethanesulfonic acid [1493-13-6] is a stable, hydroscopic Hquid which fumes in air. Addition of an equimolar amount of water to the acid results in a stable, distillable monohydrate, mp 34°C, bp 96°C at 0.13 kPa (1 mm Hg) (18). Measurement of conductivity of strong acids in acetic acid has shown the acid to be one of the strongest protic acids known, similar to fluorosulfonic and perchloric acid (19). 

In the presence of strongly acidic media, such as triflic acid, hydrogen cyanide or trimethylsilyl cyanide formylates aromatics such as ben2ene. Diprotonotated nittiles were proposed as the active electrophilic species in these reactions (119). 

Departures from the ideal behavior expressed by equation 7 usually are found in alkaline solutions containing alkaH metal ions in appreciable concentration, and often in solutions of strong acids. The supposition that the alkaline error is associated with the development of an imperfect response to alkaH metal ions is substantiated by the successhil design of cation-sensitive electrodes that are used to determine sodium, silver, and other monovalent cations (3). 

Ca.ta.lysis by Protons. The discovery of hydrogen peroxide hydroxylation of phenol in the presence of strong acids such as perchloric, trifluoromethane-sulfonic, or sulfuric acids allows suppression of all previous drawbacks of the process (18,19). This mode of hydroxylation gives high yields (85% based on H2O2 at phenol conversion of 5—6%). It can be mn without solvents and does not generate resorcinol. Its main advantage rehes on... 

Reaction with Oxygen Nucleophiles. In the presence of strong acids, eg, H2SO4, HBF, or BF, aziridines react with alcohols to form P-amino ethers (93) ... 

Reaction with esters of strong acids, such as formates or oxalates, yields the acyl derivatives of ethyleneimine dimer (238,239). 

Chlorfenethol [80-08-6] l,l-bis(p-chlorophenyl)ethanol, R = H (139), is a white soHd (mp 70°C). The compound is readily dehydrated upon heating or in the presence of strong acids and forms the inactive l,l-bis( chlorophenyl)ethylene. Chlorfenethol is active against all stages of mites. It has an oral LD q to the rat of ca 200 mg/kg. 

Solutions of alkah metal and ammonium iodides in Hquid iodine are good conductors of electricity, comparable to fused salts and aqueous solutions of strong acids. The Hquid is therefore a polar solvent of considerable ionising power, whereas its own electrical conductivity suggests that it is appreciably ionized, probably into I" and I (triodide). Iodine resembles water in this respect. The metal iodides and polyiodides are bases, whereas the iodine haHdes are acids. 

Weak Base. Weak base anion-exchange resins may have primary, secondary, or tertiary amines as the functional group. The tertiary amine -N(CH2)2 is most common. Weak base resins are frequentiy preferred over strong base resins for removal of strong acids in order to take advantage of the greater ease in regeneration. 

In the presence of strong acid, such as boron trifluoride [7637-07-2] appropriately substituted acyl chlorides (7, R = CCl ) add to ketene to form the corresponding acetoacetyl chlorides, which can further react with alcohols to form the corresponding acetoacetates. 

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