N-sulphonic acids

N-substituted phenylhydroxylamine derivatives, e.g. N-acetyl and N-sulphonic acid, also form the para-aminophenol", but more bulky groups prevent reaction, it is thought by steric hindrance to the approach of the hydronium ion. -substituted phenylhydroxylamines, on the other hand form only the ortho product, it is thought via an intramolecular rearrangement, e.g. 

If, however, the water formed is removed as formed (compare the preparation of di-n-butyl ether. Section 111,57), the sulphuric acid may react completely and the method may be employed for the preparation of the free sulphonic acid. 

Chapter IV. a-Chloromethylnaphthalene (IV,23) benzylamine (Gabriel synthesis) (IV,39) i r.N -dialkylanilines (from amines and trialkyl orthophosphates) (IV,42) a-naphthaldehyde (Sommelet reaction) (IV,120) a-phenyl-cinnamic acid (Perkin reaction using triethylamine) (IV,124) p-nitrostyrene (IV,129) p-bromonaphthalene and p naphthoic acid (from 2 naphthylamine-1 -sulphonic acid) (IV,62 and IV,164) diphenic acid (from phenanthrene) (IV,165). 

Most of the inhibitors in use are organic nitrogen compounds and these have been classified by Bregman as (a) aliphatic fatty acid derivatives, b) imidazolines, (c) quaternaries, (d) rosin derivatives (complex amine mixtures based on abietic acid) all of these will tend to have long-chain hydrocarbons, e.g. CigH, as part of the structure, (e) petroleum sulphonic acid salts of long-chain diamines (preferred to the diamines), (/) other salts of diamines and (g) fatty amides of aliphatic diamines. Actual compounds in use in classes (a) to d) include oleic and naphthenic acid salts of n-tallowpropylenediamine diamines RNH(CH2) NH2 in which R is a carbon chain of 8-22 atoms and x = 2-10 and reaction products of diamines with acids from the partial oxidation of liquid hydrocarbons. Attention has also been drawn to polyethoxylated compounds in which the water solubility can be controlled by the amount of ethylene oxide added to the molecule. 

With fluoro- or chloro-sulphonic acids the P=N linkage is replacedby an S-N bond ... 

Tomigahara Y, Mori M, Shiba K, Isobe N, Kaneko H, Nakatsuka I, Yamada H (1994) Metabolism of tetramethrin isomers in rat I. Identification of a sulphonic acid type of conjugate and reduced metabolites. Xenobiotica 24 473 -84... 

In some cases where it is difficult to carry out the Bucherer reaction successfully, it is easier to prepare N-arylnaphthylamines by heating together a naphthylamine and an arylamine. In particular, this reaction is useful in the preparation (Scheme 4.24) of 1-phenylaminonaphthalene-8-sulphonic acid (4.34 N-Phenyl Peri acid) and its N-4-methylphenyl analogue (Tolyl Peri acid), both of which intermediates are valuable components for the production of navy blue dyes. 

Superior passive stabilised diazo compounds are afforded by the diazoamino compounds (triazenes) that arise by reaction of diazonium salts with a variety of secondary amines [114]. Typically, sarcosine (CH3NHCH2COOH), which gives products based on structure 4.114, as well as N-methyltaurine (CH3NHCH2CH2SO3H) and N methylaniline-4 Sulphonic acid,... 

Dyes in this hue sector are also derived from ] acid, N-methyl ] acid or y acid but the diazo component is usually a sulphonated 2- or 4-anisidine, as a methoxy substituent has a bathochromic influence. The highly substantive structure 7.94 is found in various haloheterocyclic (Z) dyes. As in the orange region, vinylsulphone dyes have the precursor grouping located on the diazo arylamine, as exemplified by structure 7.95. 

Fig. 17.7 Influence of Na+ concentration at interface of sulphonic acid and carboxylic layers on current efficiency 3-4 N NaCI 1.0-5.5 kA rrT2 33% NaOH.

A very elegant process for the direct preparation of the free naphthalene-/3-sulphonic acid from its components has been described by 0. N. Witt (Ber., 1915, 48, 751). It is specially recommended as an alternative to the process described above. 

Fig. 3.12. Synthesis of the compounds by the methods (a) and (b). A = -NHC6H4S03H (dye la) A = -NHCH2CH=CH (dye lb) A = -OCH2CH=CH2 (dye lc). SP = N-(4 -sulpho)phenyl-3-methy 1-5-pyrazolone m-PDA = l,3-phenylendiamine-4-sulphonic acid. Reprinted with permission from T. Konstantinova et al. [90],...

N-Aryl amides of sulphonic acids (X = —S02R, Y = H Section VI). 

Solid esters are easily crystallisable materials. It is important to note that esters of alcohols must be recrystallised either from non-hydroxylic solvents (e.g. toluene) or from the alcohol from which the ester is derived. Thus methyl esters should be crystallised from methanol or methanol/toluene, but not from ethanol, n-butanol or other alcohols, in order to avoid alcohol exchange and contamination of the ester with a second ester. Useful solvents for crystallisation are the corresponding alcohols or aqueous alcohols, toluene, toluene/petroleum ether, and chloroform (ethanol-free)/toluene. Carboxylic acid esters derived from phenols are more difficult to hydrolyse and exchange, hence any alcoholic solvent can be used freely. Sulphonic acid esters of phenols are even more resistant to hydrolysis they can safely be crystallised not only from the above solvents but also from acetic acid, aqueous acetic acid or boiling n-butanol. 

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