Naphtols

Can be coupled in the 4-position with dia-zotized bases to give a series of azo dyestuffs more usually it is first sulphonated to give a valuable series of intermediates for solubilized azo dyestuffs. The nitro-l-naphthols are themselves dyestuffs, e.g. 2,4-dinitro-l-naph-thol ( naphtol yellow ). 

A significant group of carbonamides are the Naphtol products formed by condensation of 2-hydroxy-3-naphthoic acid (via its acid chloride) with a wide range of arylamines. The simplest example, Naphtol AS from aniline, is typical, and manufacture is accompHshed by suspending the acid ia a solvent such as toluene, preforming the acid chloride by addition of phosphoms trichloride, and then adding the aniline. 

RAPID PHOTOMETRIC METHODS FOR WATER ANALYSIS IN FIELD. EXTRACTION-FREE RAPID PROCEDURES FOR THE DETERMINATION OF TRACES OF REGULATED METALS WITH l-(2-PYRIDYLAZO)-NAPHTOL-2... 

Development of extraction-free photometric procedures for the determination of traces of metals for which hygienic and environmental regulations have been established is an urgent problem. For solution of this problem we used as an organic reagent l-(2- pyridylazo)-naphtol-2 (PAN) which forms intensely coloured complex compounds with many metals and is frequently used for their extraction-photometric determination however these procedures did not find wide application in water analysis due to lack of selectivity and necessity of using organic solvents. 

SOLID-PHASE EXTRACTION ON SIMULTANEOUS SPECTROPHOTOMETRIC DETERMINATION TRACE IONS IN WATER WITH l-(2-PYRIDILAZO)-2-NAPHTOL... 

Co (II) with 2-nitroso-I-naphtol in the presenee of diphenylguanidine and NiSO on the bases of PUT and MSA ... 

The reactivity of the 5-position of 2-aminothiophene in diazo coupling, which is present also in the acylated derivatives, complicates the formation of a diazonium salt from 2-aminothiophene. Thus Steinkopf and Miiller obtained only an azo dyestuff, although they proved, through the isolation of small amounts of 2-thienyl diazonium chloride, the diazotizability of 2-aminothiophene which had earlier been denied. However, recent Russian work claims the preparation of 2-thienyldiazonium chloride by treating the double salt in 10% hydrochloric acid with sodium nitrite. Amazingly high yields (over 90%) of azo compounds were then achieved by coupling the diazonium salt solution with y9-naphtol, w-toluidine or with the 2-aminothiophene double salt. These authors have also studied the... 

Alpha-gras, n. alfa grass, esparto, -milchsaure, /. (,o -)lactic acid, -naphtol, n. alpha naphthol, a-naphthol (l-naphthol). -strahlen, m.pl. alpha rays, -zellstoff, m. alpha cellulose. Alpranken, f.pl. bittersweet (Solanum dulcamara). 

Beta-naphtol, n. beta naphthol, /3-naphthol (2-naphthol). -strahlen. m.pl. beta rays, betatigen, v.t. operate put into operation, start prove, manifest.—v.r. prove participate (in). 

RajanBabu reported the first preparation of a bis-imidazolium salt 15 bearing a chiral linker (Scheme 11). The starting material was the enantiomerically pure (S)-l,l -bi-2-naphtol bis(trifluoromethanesulfonate) which was transformed in two steps into the dibromomethyl derivative 16 and then into the bis-imidazole. Quaternarization of this compound afforded 15 [20]. 

Acid Orange 7 Sludge originally collected from a pulp and paper wastewater treatment plants Color removal of 96% was achieved in the presence of liposomes that facilitated uptake of dyes by anaerobic biomass, leading to a fast decolorization. Amines such as sulfanilic acid and aniline were mineralized by inocula with high microbiological diversity, even with domestic effluent. Orthanilic and metanilic acids and 1-amino-2-naphtol were persistent under tested conditions [176]... 

FIGURE 14.1 Oxidation of cyclohexanone kinetic curves of 1-naphtol decay (curves without primes) and hydroperoxide formation (curves with primes) at T — 413K(1, l ),403K(2, 2 ), and 393 K (3, 3 ). 

The rare example of synergistic action of a binary mixture of 1-naphthyl-A-phcnylaminc and phenol (1-naphthol, 2-(l,l-dimethylethyl)hydroquinone) on the initiated oxidation of cholesterol esters was evidenced by Vardanyan [34]. The mixture of two antioxidants was proved to terminate more chains than both inhibitors can do separately ( > /[xj). For example, 1-naphtol in a concentration of 5 x 10 5 mol L-1 creates the induction period t=170s, 1 -naphthyl-A-phenylamine in a concentration of 1.0 x 10-4 mol L 1 creates the induction period t = 400s, and together both antioxidants create the induction period r = 770 s (oxidation of ester of pelargonic acid cholesterol at 7= 348 K with AIBN as initiator). Hence, the ratio fs/ZfjXi was found equal to 2.78. The formation of an efficient intermediate inhibitor as a result of interaction of intermediate free radicals formed from phenol and amine was postulated. This inhibitor was proved to be produced by the interaction of oxidation products of phenol and amine. 

Naphtho-thietes, 21 151 Naphtol products, 9 281 1-Naphthylacetic acid derivatives, 12 176 1-Naphthyl chloroformate, molecular formula, 6 291t... 

Stable mixtures of anti-diazotates and Naphtols were marketed as Rapid Fast colours for printing onto fabric with development of the azoic dye by steaming. The anti-diazosulphonates (4.113) [113], which were prepared by treatment of a diazonium salt with sodium sulphite and which regenerate the diazonium ion on treatment with an oxidising agent, found similar use. Both ranges are now of only historical interest. 

These products, which have been copied by other manufacturers under various tradenames, are designed specifically for printing applications. Azoic dyeing applications were catered for in 1967 when Hoechst introduced the Azanil salts, a limited range of mixtures of substantive triazenes and Naphtols that can be absorbed onto the fabric and the colour developed by acidification of the dyebath. 

In the red to violet sector Naphtol AS and its derivatives are widely used. Simple monoazo combinations such as 2,5-dichloroaniline and Naphtol AS serve where high heat and solvent fastness are not essential, but for better properties polar features, such as amide linkages, are incorporated. Cl Pigment Red 245 (4.119), Cl Pigment Red 188 (4.120) and... 

The coupling of Naphtol AS or its phenyl-substituted derivatives with diazonium salts from variously substituted anilines in aqueous alkaline solution (section 4-11) gave incomplete reactions and impure products in some instances, probably because these coupling components have inadequate solubility in aqueous media. Pure dyes in ca. 90% yields were obtained by reaction in dimethylformamide in the presence of sodium acetate. Metallisation of these o,o -dihydroxyazo ligands with sodium chromium salicylate or a cobalt(II) salt gave metal-complex dyes in 80-100% yields [22]. Specific structural isomers of these complexes were identified by i.r., n.m.r., Raman and UV/visible spectroscopy [23]. 

A few Naphthol Yellow pigments which are coupling components of the acetoacetic arylide series are also considered members of the Naphthol AS series (see footnote to Table 10, p. 191). These are internationally known as Naphtol AS-G , Naphtol AS-IRG , etc. Naphtol AS-IRG, for instance, is acetoacetic-2,5-methoxy-4-chloroanilide (see also Table 10). 

Table 10 Important Naphtol AS derivatives as coupling components for azo pigments.

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