2- Naphthol preparation

I, 4-benzoquinone.4 Other methods that have been employed include the oxidation of naphthalene with hydrogen peroxide,5 the oxidation of 1,4-naphthalenediamine 6 and naphthylamine sulfonic acid 7 and the oxidation of 4-amino-1-naphthol prepared by electrolytic reduction of 1-nitronaphthalene.8... 

A contact insecticide with the trade name Sevin . White solid, m.p. 142 C. It is prepared by reaction of I-naphthol with methyl isocyanate or with phosgene and a base. 

Schaffer s acid, CioHg04S. 2-hydroxy-7-naphthalene sulphonic acid. Obtained by sulphonating 2-naphthol with a small amount of sulphuric acid at a higher temperature than is used for the preparation of crocein acid. A valuable dyestuff intermediate. 

The procedure is not usually applicable to aminosulphonic acids owing to the interaction between the amino group and the phosphorus pentachloride. If, however, the chlorosulphonic acid is prepared by diazotisation and treatment with a solution of cuprous chloride in hydrochloric acid, the crystalline chlorosulphonamide and chlorosulphonanilide may be obtained in the usual way. With some compounds, the amino group may be protected by acetylation. Sulphonic acids derived from a phenol or naphthol cannot be converted into the sulphonyl chlorides by the phosphorus pentachloride method. 

A fairly general procedure consists in coupling a phenol or naphthol with a diazotised amine, reducing the product to an aminophenol or aminonaphthol, and oxidising the hydroxy compound with acid ferric chloride solution. This method is illustrated by the preparation of (3 (or 1 2)-naphthoquinone ... 

Triflates of phenols are carbonylated to form aromatic esters by using PhjP[328]. The reaction is 500 times faster if dppp is used[329]. This reaction is a good preparative method for benzoates from phenols and naphthoates (473) from naphthols. Carbonylation of the bis-triflate of axially chiral 1,1 -binaphthyl-2,2 -diol (474) using dppp was claimed to give the monocarboxy-late 475(330]. However, the optically pure dicarboxylate 476 is obtained under similar conditions[331]. The use of 4.4 equiv. of a hindered amine (ethyldiisopropylamine) is crucial for the dicarbonylation. The use of more or less than 4.4 equiv. of the amine gives the monoester 475. 

Isopropylnaphthalenes can be prepared readily by the catalytic alkylation of naphthalene with propjiene. 2-lsopropylnaphthalene [2027-17-0] is an important intermediate used in the manufacture of 2-naphthol (see Naphthalenederivatives). The alkylation of naphthalene with propjiene, preferably in an inert solvent at 40—100°C with an aluminum chloride, hydrogen fluoride, or boron trifluoride—phosphoric acid catalyst, gives 90—95% wt % 2-isopropylnaphthalene however, a considerable amount of polyalkylate also is produced. Preferably, the propylation of naphthalene is carried out in the vapor phase in a continuous manner, over a phosphoric acid on kieselguhr catalyst under pressure at ca 220—250°C. The alkylate, which is low in di- and polyisopropylnaphthalenes, then is isomerized by recycling over the same catalyst at 240°C or by using aluminum chloride catalyst at 80°C. After distillation, a product containing >90 wt % 2-isopropylnaphthalene is obtained (47). 

Naphthaleneamine. 1-Naphthylamine or a-naphth5iamine/7i5 -i2- can be made from 1-nitronaphthalene by reduction with iron—dilute HCl, or by catalytic hydrogenation it is purified by distillation and the content of 2-naphthylamine can be reduced as low as 8—10 ppm. Electroreduction of 1-nitronaphthalene to 1-naphthylamine using titania—titanium composite electrode has been described (43). Photoinduced reduction of 1-nitronaphthalene on semiconductor (eg, anatase) particles produces 1-naphthylamine in 77% yield (44). 1-Naphthylamine/7J4-J2-. can also be prepared by treating 1-naphthol with NH in the presence of a catalyst at elevated temperature. The sanitary working conditions are improved by gas-phase reaction at... 

Naphthol is mainly used in the manufacture of the insecticide carbaryl (59), l-naphthyl A/-methyicarbamate/ iJ-2j5 - (Sevin) (22), which is produced by the reaction of 1-naphthol with methyl isocyanate. Methyl isocyanate is usually prepared by treating methylamine with phosgene. Methyl isocyanate is a very toxic Hquid, boiling at 38°C, and should not be stored for long periods of time (Bhopal accident, India). India has developed a process for the preparation of aryl esters of A/-alkyl carbamic acids. Thus l-naphthyl methylcarbamate is prepared by refluxing 1-naphthol with ethyl methylcarbamate and POCl in toluene (60). In 1992, carbaryl production totaled > 11.4 x 10 t(35). Rhc ne-Poulenc, at its Institute, W. Va., facihty is the only carbaryl producer in United States. 

Devrinol, 2-(l-naphthoxy)-Al,A/-diethylpropionamide/7 i25 5 -5 5 -7/ (napropamide) (23), which is prepared from 1-naphthol, is used as a herbicide (61). Another agricultural chemical, 1-naphthoxyacetic 2Lcid[2976-75-2] (24), is prepared by stirring 1-naphthol with monochloroacetic acid and sodium hydroxide in water at 100—110°C for several minutes. After treatment with concentrated HCl about 94% of the product is obtained (62). 

Naphthalenol also is used ia the preparation of azo, iadigoid, and nitro, eg, 2,4-dinitro-l-naphthol, dyes, and ia making dye iatermediates, eg, naphtholsulfonic acids, 4-chloro-1-naphthalenol, and l-hydroxy-2-naphthoic acid. 1-Naphthalenol is an antioxidant for gasoline, and some of its alkylated derivatives are stabilizers for plastics and mbber (68). 

Naphthalenediol. This diol is prepared by the alkah fusion of 2-hydroxynaphthalene-6-sulfonic acid (Schaffer acid) at 290—295°C. Schaffer acid is usually produced by sulfonation of 2-naphthol with the addition of sodium sulfate at 85—105°C. This acid is also used as a coupling component in the production of a2o dyes such as Acid Black 26. 2,6-Naphthalenediol is used as a component in the manufacture of aromatic polyesters which, as is also tme of the corresponding amides, display Hquid crystal characteristics (52). 

The N,]S7 - diphenyl- -phenylenediamine is prepared by heating hydroquiaone with aniline ia the presence of phosphoric acid (29). A[,Ar-di-2-naphthalenyl-/)-phenylenediamiQe is made from -phenylenediamine and 2-naphthol. 

Sulfation by sulfamic acid has been used ia the preparation of detergents from dodecyl, oleyl, and other higher alcohols. It is also used ia sulfating phenols and phenol—ethylene oxide condensation products. Secondary alcohols react ia the presence of an amide catalyst, eg, acetamide or urea (24). Pyridine has also been used. Tertiary alcohols do not react. Reactions with phenols yield phenyl ammonium sulfates. These reactions iaclude those of naphthols, cresol, anisole, anethole, pyrocatechol, and hydroquinone. Ammonium aryl sulfates are formed as iatermediates and sulfonates are formed by subsequent rearrangement (25,26). 

Direct Blue 218 had reported sales of 623 t valued at 4.4 million ia 1987. It is produced from Direct Blue 15 (76) by metallizing and elimination of methyl groups from the methoxide to form the copper complex. Direct Blue 15 (76) is prepared by coupling o-dianisidine [119-90-4] to two moles of H-acid (4-amiQO-5-hydroxy-2,7-naphthalenedisulfonic acid) under alkaline pH conditions. Other important direct blues iaclude Direct Blue 80 (74), (9-dianisidine coupled to two moles of R-acid (3-hydroxy-2,7-naphthalenedisulfonic acid [148-75-4]) followed by metallizing to form a bis copper complex, and Direct Blue 22 (77), an asymmetrical disazo dye, prepared by coupling o-dianisidine to Chicago acid [82-47-3] and 2-naphthol. Direct Blue 75 (78) is an example of a trisazo dye represented as metanilic acid — 1,6-Q.eve s acid — 1,6-Q.eve s acid — (alb) Ai-phenyl J-acid. 

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. 

The alternative approach is to pad the fabric with the alkaline naphthol and dry, foUowed by printing directly onto this prepared fabric diazonium salts or stabilized diazonium salts. Coupling is instant and the only further treatment needed is to remove aU the uncoupled naphthol and surface azo pigment in a subsequent washing treatment. Because the choice of colors is limited from one naphthol component, other shades are obtained by using other classes of dye alongside the azoic colors, eg, reactives. This approach is widely used in the production of African prints. 

Zn, HOAc, 25°, 1 h, 88-96% yield. Phenacyi andp-bromophenacyl ethers of phenols are stable to 1 % ethanolic alkali (reflux, 2 h), and to 5 N sulfuric acid in ethanol-water. The phenacyi ether, prepared from /3-naphthol, is cleaved in 82% yield by 5% ethanolic alkali (reflux, 2 h). 

This method has been used for the preparation of other phenolic ketones such as resacetophenone, 2-acetyl-i-naphthol,i 2-phenylacetyl-i-naphthol and 2-phenylpropionyl-i-naphthol. ... 

A) Diazotizalion of Sulfanilic Acid.—A mixture of 105 g. (0.5 mole) of sulfanilic acid dihydrate, 26.5 g. (0.25 mole) of anhydrous sodium carbonate, and 500 cc. of water is heated and stirred until all the sulfanilic acid has dissolved, and the solution is then cooled in an ice bath to 15° (sodium sulfanilate begins to crystallize at this temperature). A solution of 37 g. (0.54 mole) of sodium nitrite in 100 cc. of water is added and the resulting solution is poured at once onto a mixture of 106 cc. (1.25 moles) (Note i) of concentrated hydrochloric acid (sp. gr. 1.18) and 600 g. of ice contained in a 2-I. beaker. The solution, from which -benzenediazonium sulfonate separates on stirring, is allowed to stand in an ice bath for fifteen to twenty-five minutes, during which time the naphtholate solution is prepared. 

The only practical method of preparing 1,4-aminonaphthol is from a-naphthol through an azo dye, the nitroso compound not being readily available. The majority of investigators have reduced technical Orange I with stannous chloride Mi.is.is.ir.is by the procedures discussed above, and benzeneazo-a-naphthol has been reduced by the same reagent. In order to make possible the use of crude, technical a-naphthol a method has been developed for the preparation of the benzeneazo compound, its separation from the isomeric dye coming from the d-naphthol present as well as from any disazo compound by extraction with alkali, and the reduction of the azo compound in alkaline solution with sodium hydrosulfite. The process, however, is tedious and yields an impure product. 

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