Naphthalene-1,3-disulfon> 1 chloride

In acid medium, fluoride reacts instantaneously with zirconyl-dye lake which is composed of zirconyl chloride octahydrate, ZrOCl2 8 H20, and sodium 2-(parasulfophenylazo)-l,8-dihydroxy-3,6-naphthalene disulfonate (SPADNS), displacing the Zr2+ from the dye lake to form a colorless complex anion, ZrF62 and the dye. As a result, the color of the solution lightens as the concentration of F increases. 

Zirconyl-acid-SPADN reagent is made by combining equal volumes of sodium 2-(parasulfophenylazo)-l,8-dihydroxy-3,6-naphthalene disulfonate (SPADN) with zirconyl-acid reagent. The former is prepared by dissolving 1 g of it in 500 mL distilled water. The latter is made by dissolving 0.14 g zirconyl chloride octahydrate in 50 mL of distilled water followed by addition of 350 mL cone. HC1 and dilution to 500 mL. 

C5H15NO2 123-41-1) see Acetylcholine chloride Choline chloride Choline dihydrogen citrate Choline stearate choline naphthalene-1,5-disulfonate (C20H34N2O8S2) see Aclatonium napadisilate choline tosylate... 

In a 1-1. round-bottomed flask is placed a mixture of 204.3 g. (1 mole) of finely divided phosphorus pentachloride and 132.8 g. (0.4 mole) of the disodium salt of naphthalene-1,5-disulfonic acid which has been dried previously at 140° for 48 hours (Note 1). The flask is provided with an air condenser which is fitted at the top with a calcium chloride drying tube. It is then placed in an oil bath which is heated to 110°, and the mixture is maintained at that temperature for 1 hour. The condenser is removed for brief intervals now and then during the heating period, and the reactants are stirred by means of a glass rod. At the end of the heating period, the product is a thick paste. 

There is surprisingly little reliable information on the sulfonation of benzo[6]thiophene or its derivatives. Benzo[6]thiophene is more readily sulfonated than naphthalene.699 Reaction with concentrated sulfuric acid at 80° gives a mixture of mono-, di-, and trisulfonic acids, reaction with 70% sulfuric acid at 80° gives a monosulfonic acid,699 and reaction with 18% oleum gives a disulfonic acid 86 in each case the orientation of the products is unknown. Treatment of benzo[6]thiophene with concentrated sulfuric acid in acetic anhydride at 20° gives 3-acetylbenzo[6]thiophene (ca. 10%) and a sulfonation product (isolated as the potassium salt), which was believed to be the 3-sulfonic acid.660 Recently, the sulfonation product has been shown to contain the 2- (8%) and 3-isomer (92%), by conversion into the sulfonyl chlorides and reduction to a separable mixture of 2- and 3-mercaptobenzo[6]thiophene.84... 

Naphthaldehyde, 30, 67, 68 Naphthalene-1,5-disulfonic acid, 32, 88 Naphthalene-1,5-disulponyl chloride, 32, 88 /3-Naphthol, 32, 11, 100... 

In place of sodium hydroxide, sodium acetate may be added to the mixture of diazonium salt solution and the aromatic liquid.6 Another variation, introduced by Hodgson and Marsden,6 consists in converting the aryldiazonium chloride to a stabilized diazonium salt by treatment wi,th naphthalene-l-sulfonic acid, naphthalene-1,5-disulfonic acid, or zinc chloride the dried salt is then suspended in an aromatic liquid and treated with sodium acetate and acetic anhydride. 

Preconcentration of trace nickel with the ion pair of disodium l-nitroso-2-naphthol-3,6-disulfonate and tetradecyldimethylbenzylammonium chloride on microcrystalline naphthalene (or by the column method) was applied prior to the determination of Ni in standard alloy, steel and biological samples by derivative spectrophotometry [1]. The detection limit of 10 ppb was repotted. 

In the disulfonation of naphthalene 40, the two sulfonic acid groups are never 0-, p- or /7eri-(l,8)- with respect to each other. Naphthalene, by treatment with chlorosulfonic acid (two equivalents) at 15-45 °C, yields a mixture of the 1,5-disulfonic acid and the 1,5-disulfonyl chloride. ... 

The stabihzation of some diazonium salts may be carried out by the addition of naphthalene-1,5-disulfonic acid or 2-naphthol-l-sulfonic acid to the hydrochloric salt solution produced after diazotization [33]. The usual procedure simply involves addition of a slurry of acids to the diazonium salt solutions and, if necessary, assisting the precipitation of the product by the addition of sodium chloride. Some... 

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