A-,P-Naphthol

Evidence for this mechanism was the isolation of 12 and the demonstrati on that for P-naphthol treated with ammonia and HSO3, the rate of the reaction depends only on the substrate and on HS03 , indicating that ammonia is not involved in the rate-determining step. If the starting compound is a P-naphthol,... 

In this sequence29,30 a (substituted or unsubstituted) benzophenone (15) is reacted witb sodium acetylide (16) in an etber solvent at room temperature to yield a 1,1-diaiyl-2- propyn-l-ol (17). This intermediate can be condensed with a P-naphthol in the presence of an acid catalyst at 30 to 50°C to yield the pyran. 

A more recent report on the use of PPE to promote cyclization of a P-naphthol has appeared. The reagent allowed product formation in excellent yield at room temperature. Such results were a great improvement to the reaction conditions and yield typically obtained in the Simonis chromone synthesis. 2,6-Dihydroxy-naphthol 35 gave chromone 36 in 98% yield. 

Dilute sodium hydroxide solution (and also sodium carbonate solution and sodium bicarbonate solution) can be employed for the removal of an organic acid from its solution in an organic solvent, or for the removal of acidic impurities present in a water-insoluble solid or liquid. The extraction is based upon the fact that the sodium salt of the acid is soluble in water or in dilute alkali, but is insoluble in the organic solvent. Similarly, a sparingly soluble phenol, e.g., p-naphthol, CioH,.OH, may be removed from its solution in an organic solvent by treatment with sodium hydroxide solution. 

Mix together 1 0 g. of pure p-naphthol and the theoretical quantity of 50 per cent, potassium hydroxide solution, add 0-5 g. of the halide, followed by sufficient rectified spirit to produce a clear solution. For alkyl chlorides, the addition of a little potassium iodide is recommended. Heat the mixture under reflux for 15 minutes, and dissolve any potassium halide by the addition of a few drops of water. The p-naphthyl ether usually crystallises out on cooling if it does not, dilute the solution with 10 per cent, sodium hydroxide solution untU precipitation occurs. Dissolve the p-naphthyl ether in the minimum volume of hot alcohol and add the calculated quantity of picric acid dissolved in hot alcohol. The picrate separates out on cooling. Recrystallise it from rectified spirit. 

It is interesting to note that azo dyestuffs may be conveniently reduced either by a solution of stannous chloride in hydrochloric acid or by sodium hyposulphite. Thus phenyl-azo-p-naphthol 3delds both aniline and a-amino-p-naphthol (see formula above), and methyl orange gives p-aminodimethylaniline and sulphanilic acid ... 

P-Naphthyl acetate. Dissolve 5 0 g. of p-naphthol in 25 ml. of 10 per cent, sodium hydroxide solution in a 250 ml. reagent bottle, add 60 g. of crushed ice, and 5-7 g. (5 -5 ml.) of acetic anhydride. Shake vigorously for 10-15 minutes the p-naphth acetate separates as colourless crystals. Filter with suction, wash with water, drain and dry in the air. Recrystallise from light petroleum (b.p. 60-80°) or from dilute alcohol. The yield of pure product, m.p. 71°, is 6-5 g. 

P-Hydroxy-a-naphthaldehyde, Equip a 1 litre three-necked flask with a separatory funnel, a mercury-sealed mechanical stirrer, and a long (double surface) reflux condenser. Place 50 g. of p-naphthol and 150 ml. of rectified spirit in the flask, start the stirrer, and rapidly add a solution of 100 g. of sodium hydroxide in 210 ml. of water. Heat the resulting solution to 70-80° on a water bath, and place 62 g. (42 ml.) of pure chloroform in the separatory funnel. Introduce the chloroform dropwise until reaction commences (indicated by the formation of a deep blue colour), remove the water bath, and continue the addition of the chloroform at such a rate that the mixture refluxes gently (about 1 5 hours). The sodium salt of the phenolic aldehyde separates near the end of the addition. Continue the stirring for a further 1 hour. Distil off the excess of chloroform and alcohol on a water bath use the apparatus shown in Fig. II, 41, 1, but retain the stirrer in the central aperture. Treat the residue, with stirring, dropwise with concentrated hydrochloric acid until... 

Place 20 g. of Orange II (Section IV,79) in a 600 ml. beaker and dissolve it in 250 ml. of water at 40-50°. Add, with stirring, 24-25 g. of sodium hyposulphite (Na SjO ) this discharges the colour and yields a pink or cream-coloured, finely-divided precipitate of a-amino-p-naphthol (compare Section IV,76). Heat the mixture nearly to boiling until it commences to froth considerably, then cool to 25° in ice, filter on a... 

Naphthyl benzoate. Dissolve 7 2 g. of p-naphthol in 40 ml. of 5 per cent, sodium hydroxide solution in the cold add a httle more water if necessary. If the solution is highly coloured, add 1 - 5 g. of decolourising... 

Treatment of a solution of sodium nitrite and the sodium salt of p-naphthol with sulphuric acid gives an excellent jdeld of a-nitroso- p-naphthol ... 

Dissolve 100 g. of p-naphthol (Section IV,102) in a warm solution of 28 g. of sodium hydroxide in 1200 ml. of water contained in a 2-5 htre round-bottomed or bolt-head flask fitted with a mechanical stirrer. Cool the solution to 0° in a bath of ice and salt, and add 50 g. of powdered sodium nitrite. Start the stirrer and add, by means of a separatory funnel supported above the flask, 220 g. (166-5 ml.) of sulphuric acid (sp. gr. 1 32) at such a rate that the whole is added during 90 minutes... 

If a-nitroso-p-naphthol is required in the crystalline condition, recrystallise it from light petroleum, b.p. 60-80° (7 -5 ml. per gram) the recovery is almost quantitative, m.p. 106°. 

Naphthalenol. 2-Naphthol or p-naphthol or 2-hydroxynaphthalene/7i3 -/5 -i7 melts at 122°C and boils at 295°C, and forms colorless crystals of characteristic, phenoHc odor which darken on exposure to air or light. 2-Naphthol [135-19-3] is manufactured by fusion of sodium 2-naphthalenesulfonate with sodium hydroxide at ca 325°C, acidification of the drowned fusion mass which is quenched ia water, isolation and water-washing of the 2-naphthalenol, and vacuum distillation and flaking of the product. A continuous process of this type has been patented (69). The high sulfate content ia the primary effluent from 2-naphthol production is greatiy reduced ia modem production plants by the recovery of sodium sulfate. 

Naphthalene. Until the 1960s, the principal outlet for naphthalene was the production of phthaHc anhydride however, more recently, o-xylene has replaced naphthalene as the preferred feedstock (see Phthalic acids). Nevertheless, of the 201,000 t produced in 1994 in Japan, 73.2% was used for phthaHc anhydride production. The rest was consumed in dye stuffs manufacture and a wide variety of other uses. Naphthalene is also used to produce phthaHc anhydride in the United Kingdom, Belgium, and the C2ech RepubHc, and can be used by Koppers in the United States in time of o-xylene shortages. In Europe, the traditional uses for naphthalene have been for the manufacture of P-naphthol and for dye stuff intermediates (see Dyes and dye... 

An electrorefining plant may operate with either an acid or an alkaline bath. The acid bath contains stannous sulfate, cresolsulfonic or phenolsulfonic acids (to retard the oxidation of the stannous tin in the solution), and free sulfuric acid with P-naphthol and glue as addition agents to prevent tree-like deposits on the cathode which may short-circuit the cells. The concentration of these addition agents must be carefliUy controlled. The acid electrolyte operates at room temperature with a current density of ca 86—108 A/m, cell voltage of 0.3 V, and an efficiency of 85%. Anodes (95 wt % tin) have a life of 21 d, whereas the cathode sheets have a life of 7 d. Anode slimes may be a problem if the lead content of the anodes is high the anodes are removed at frequent intervals and scmbbed with revolving bmshes to remove the slime (7). 

Some primaries have articles devoted to them and their derivatives, ie, Benzoic ACID, Phenol, Salicylic acid, and Phthalic anhydride as a derivative of phthahc acid. The primary p-naphthol is discussed in Naphthalene derivatives. 

Figure 6 summarizes the preparation of key iatermediates from beazeae, and Figure 7 shows a dye synthesis from benzene. Figures 8 and 9 show the preparation of key iatermediates from aaphthaleae and P-naphthol. 

A mechanistic explanation of this selectivity was, however, only given in 1952 (Wittwer and Zollinger). An aminonaphthol coupling component can be considered as a superposition of a naphthol and a naphthylamine. The rates of azo couplings of both these components show the characteristic pH-dependences discussed for naphthols above. For naphthylamines it is the base, and not the ammonium ion, that reacts with the diazonium ion. This pre-equilibrium has a p Ta-value of about 4. Therefore the 1 1 gradient of log A Nh2 against pH is observed only in the range pH <4. 

Acetylene compounds Dicobaltoctacarbonyl Formation of colored complexes. After the reagent excess has been washed out, reaction with bromine vapor yields cobalt bromide, which reacts with a-nitroso-P-naphthol to yield red chromatogram zones on an almost colorless background. [11]... 

---