1,6 Cleve’s Acid

In the manufacture of 2-naphthalenol, 2-naphthalenesulfonic acid must be converted to its sodium salt this can be done by adding sodium chloride to the acid, and by neutralizing with aqueous sodium hydroxide or neutralizing with the sodium sulfite by-product obtained in the caustic fusion of the sulfonate. The cmde sulfonation product, without isolation or purification of 2-naphthalenesulfonic acid, is used to make 1,6-, 2,6-, and 2,7-naphthalenedisulfonic acids and 1,3,6-naphthalenetrisulfonic acid by further sulfonation. By nitration, 5- and 8-nitro-2-naphthalenesulfonic acids, [89-69-1] and [117-41-9] respectively, are obtained, which are intermediates for Cleve s acid. All are dye intermediates. The cmde sulfonation product can be condensed with formaldehyde or alcohols or olefins to make valuable wetting, dispersing, and tanning agents. 

In all the above sequences, single isomers are produced by careful control of the reaction conditions combined with purification by selective isolation at various points in the synthesis. Occasionally two isomers are produced which give dyestuffs that have very similar properties in these cases it is often quite acceptable and economically beneficial not to separate the individual components but to use the total mixture in dye preparation. An example is the mixture of l-naphthylamine-6- and 7-sulphonic acids (4.46 mixed Cleve s acids), which arises by nitration and reduction of naphthalene-2 Sulphonic acid (Scheme 4.30). 

Structurally related fluorescent brighteners containing a benzotriazole moiety are made according to the route shown in Fig. 13.139. In this case, diamine 59 is tetrazotized, coupled to 2 molecules of 1,6-Cleve s acid, and the intermediate disazo stilbene structure (60) is oxidized to C.I. Fluorescent Brightener 40. Nowadays, monosulfonated benzotriazole brighteners are more important.60 The synthesis of one example is shown in Fig. 13.140 for C.I. Fluorescent Brightener 46. 

Cleve s acid (l-naphthylamine-7-sulfonic acid) is used in dye manufacture. The preparation is described in U.S. 2,875,243 (to Bayer). Estimate the cost of production. 

Broenner acid Casella s acid Chicago acid (SS acid) chromotropic acid Cleve s acid crocein (Bayer s acid) epsilon acid G acid... 

Derivation Nitration of naphthalcnc-ji-sLilIonic acid. On reduction with iron, this yields amixture of l-naphthylamine-6-sulfonic acid (Cleve s acid) and l-naphthylamine-7-sulfonic acid (or Cleve s acid-1,7). The latter is separated by crystallization as the... 

Cleve s most celebrated work in organic chemistry was the preparation and characterization of the isomeric aminonaphthalenesulfonic acids, today called Cleve s acids. 

Cleve s Acid. 5-Amino-2-nupht ha letii sutjonit acid 1 -naphthylamine-6-sulfonic acid. Ci0H NO3Sl mol wt... 

Cleve s Acid, 8-Amino-2-naphthaIenesulfonic etid l-naphthylamine-7-sulfonic acid. Empirical formula etc. see 1,6-Cleve s Acid above. Prepn Erdmann, Ann. 171, 262 (1893) Roos et al. U.S, pat. 2,875,243 (1959 to Bayer). Industrial synthesis Nakahara er al., J. Syn. Org. Chem. Japan. 29, 1129 (1971). 

Aminonaphthalene-7-sulfonic acid 8-Amino-naphthalene-2-sulfonic acid 8-/kminonaphthalene-2-sulphonic acid 1-Amino-7-sulfonaphlhalene Cassella s acid C.l. 26135 Qeve s acid 1,7-Cleve s acid Cleve s theta-acid Delta acid EINECS 204-311-4 F acid J acid 2-Naphthalenesulfonic acid, 8-amino- 1-Naphthylamine-7-sulfonic acid 8-Naphthylamine-2-sulfonio acid NSC 4983. Used as an intermediate for azo dyes. Crystallizes as the monohydrate, soluble in H2O (0.45 g/100 ml). 

Beilstein Handbook Reference) 5-Amino-2-naphthalenesulfonic acid 5-Amino-naphthalene-2-sulphonic acid 1-Amlno-6-sulfo-naphthalene 1-Amino-6-naphthalenesulfonic acid BRN 1819887 1,6-Qeve s acid Cleve s p-acid Oeve s acid-1,6 Cleve s acid, mixed EINECS 204-351-2 Kyselina 1-naftylamin-6-suifonova Kyselina cleve 2-Naphthalenesulfonic acid, 5-amino- 1-Naphthylamine-6-sulfonic acid 5-Naphthylamine-2-sulfonic acid NSC 31506. Intermediate in synthesis of dyestuffs. Solid slightly soluble in 1000 parts H2O (0.1 g/100 ml), insoluble in EtOH, EI2O. 

Cleve s acid n. Old name for a-naphthol-5-sulfonic acid. It was also known as L acid and is used in the manufacture of Heho Bordeaux BL. 

---