Naphthols sulfonation

The aqueous cores of reverse micelles are of particular interest because of their analogy with the water pockets in bioaggregates and the active sites of enzymes. Moreover, enzymes solubilized in reverse micelles can exhibit an enhanced catalytic efficiency. Figure B4.3.1 shows a reverse micelle of bis(2-ethylhexyl)sulfosuccinate (AOT) in heptane with three naphthalenic fluorescent probes whose excited-state pK values are much lower than the ground-state pK (see Table 4.4) 2-naphthol (NOH), sodium 2-naphthol sulfonate (NSOH), potassium 2-naphthol-6,8-disulfonate (NSOH). The spectra and the rate constants for deprotonation and back-recombination (determined by time-resolved experiments) provide information on the location of the probes and the corresponding ability of their microenvironment to accept a proton , (i) NDSOH is located around the center of the water pool, and at water contents w = [H20]/[A0T] >... 

Fiavionic Acid. Same as 2,4-Dinicro-I-naphtho 1-7-sulfonic Acid, which will be de sctibed under Naphthol Sulfonic Acids... 

Warren, L. A., Smiles, S. Dehydro-2-naphthol sulfone. J. Chem. Soc., Abstracts 930, 1327-1331. 

Derivation Interaction of quinine and (3-naphthol-sulfonic acid. 

Naphthol- sulfonic acid (Nevile-Winther acid) Azo dyes... 

The azo dyes used in this study were l-phenylazo-2-naphthol-6-sulfonate (2) and seven derivatives with substituents in the meta or para positions of the phenyl ring (3-9). These were selected as representative l-azo-2-naphthol sulfonate dyes and because the substituents on phenyl ring would allow a systematic study of the mechanism of their oxidation by metalloporphyrin-catalysed systems in aqueous solution. Dye 2 is commercially available (as Acid Orange 12) and was purified by reciystallisation whilst the others (3-9) were prepared by standard diazonium ion/2-naphthol coupling reactions. The purities of all the dyes were checked by TLC, MS and H NMR spectroscopy. Table 1 reports the measured pl values of all the azo dyes used in this study. 

In the case of dyes having the first type of nucleus, Rigterink and France also found that those produced from /J-naphtholsulfonic acids are more adsorbable than dyes produced from a-naphthol-sulfonic acids. When an NH 2 group is substituted for an OH group, the situation is exactly reversed the dyes formed from a-naphthy-laminesulfonic acids are more adsorbable than those formed from /J-naphthylaminesulfonic acids. 

Beilstein Handbook Reference) 7-Amino-4-hydroxy-2-naphthalenesulfonic xid Amino-naphthol sulfonic acid J BRN 2217192 EINECS 201-718-9 I acid Isogamma acid J acid Kyselina 2-amino-5-naftol-7-sulfonova Kyselina 6-amino-1-naftol-3-sulfo-nova Kyselina I NSC 31510. 

ORIGIN/INDUSTRY SOURCES/USES manufacture of phthalic and anthranilic acids, naphthols, sulfonic acid, synthetic resins, celluloid, lampblack, smokeless powder, hydronaphthalenes salicylic acid indigo medication synthetic tanning chemicals surfactants insecticide wood preservative... 

Several methods have been described that employ a special substrate designed to give a colored end product after hydrolysis, or one that can be easily converted to a colored product. The p-nitrophenol liberated from the hydrolysis of p-nitrophenyl butyrate is readily measured directly (191). y8-Naphthyl laurate has been used as a substrate for serum lipase. The )8-naphfhol hberated is combined with tetrazotized di-o-anisidine to give a pigment (211, 212). Several esters of 2-naphthol-6-sulfonic acid have been used as substrates for milk lipase. The naphthol-sulfonic acid liberated is determined by the Folin-Ciocalteu reagent (213). 

Figure 13.4. Compressive strength of concrete with and without superplasticizer (0.25 wt% of sodium salt of P-naphthol sulfonate formaldehyde condensate) vs. curing time. [Data from El-Hosiny F I Gad E A M, J. Appl Polym. Set., 56, No.2, 11th April 1995, p. 153-9.]...

Solution 2. Three and one-half (3.5) grams of anhydrous sodium sulfite is dissolved in 50 ml. of distilled water. To this solution is added 0.75 g. of l-amino-2-naphthol-4-sul-fonic acid. Another solution is prepared containing 45 g. of sodium hydrogen sulfite in 400 mL of distilled water. The sulfite-naphthol-sulfonic acid solution is added to the latter and the mixture diluted to 500 ml. 

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