Naphthalene derivative

Naphthalene chemistry differs fundamentally from benzene chemistry in that two isomers can be produced by monosubstitution, facilitating the formation of byproducts. Furthermore, in comparison with benzene, naphthalene is more reactive in electrophilic substitution, so that this type of reaction can be carried out under relatively mild conditions. Naphthalene chemistry is therefore characterized by especially-optimized reaction procedures and complex refining processes. Increased reactivity and substitution capacity offer advantages which can be used, for example, in dyestuffs production, where the naphthalene moiety serves as a carrier for a variety of auxochromic groups. 

Naphthalene derivatives are of diverse importance as intermediates for agricultural, constmction, pharmaceutical, photographic, mbber, tanning, and textile chemicals. In this article production figures, economics, and processes are discussed for most commercially important compounds. Sources for a more comprehensive study of naphthalene derivatives are available (1 8). 

Several systems of nomenclature have been used for naphthalene, and many trivial and trade names are well estabUshed. The Chemicaly hstracts Index Guide is employed in this article. The numbering of the naphthalene nucleus is shown in (1) older practices are given in (2) and (3). 

Substituents in the 1,8 or 2,6 positions of naphthalene are in the peri or amphi positions, respectively. 

The number of naphthalene derivatives is very large, since the number of positional isomers is large 2 for monosubstitution, 10 for disubstitution—same substituent, 14 for disubstitition—different substituents, 14 for trisubstitution—same substituent, 42 for trisubstitution—two different substituents, 84 for trisubstitution—three different substituents, and so on with multiplying complexity. 

Naphthalenesulfonic acids are important chemical precursors for dye intermediates, wetting agents and dispersants, naphthols, and air-entrainment agents for concrete. The production of many intermediates used for making a2o, a2oic, and triphenylmethane dyes (qv) involves naphthalene sulfonation and one or more unit operations, eg, caustic fusion, nitration, reduction, or amination. 

Obtained by Fries rearrangement of 4-chloro-1-naphthyl propionate with aluminium chloride on heating in a water bath for 1.5 h 

NO2 - Obtained by reaction of fuming nitric acid with 4-pro-pionyl-l-naphthol [7756] or with 2,4-dipropionyl-l-naphthol in acetic acid [7767]. 

COCH2CH3 - Preparation by Fries rearrangement of a-naphthyl propionate. 

Preparation by reaction of propionic acid with a-naphthol, 

Also obtained by reaction of propionyl chloride with a-naphthol, 

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Fischer-Hepp rearrangement The nitros-amines of aromatic secondary amines when treated with hydrochloric acid give nuclear substituted nitrosoamines. Among the benzene derivatives, if the para position is free the -NO group displaces the hydrogen atom there in naphthalene derivatives it enters the 1-position ... 

Most naphthalene produced is utilized in the manufacture of phthalic anhydride, for plasticizers, alkyd resins and polyesters. It is also used in the manufacture of 2-naphlhol and insecticides. Naphthalene derivatives are of importance, particularly as dyestufT intermediates. 

The tendency towards a-substitution is also seen in the reactions of naphthalene derivatives containing de-activating substituents. Thus,... 

In addition to benzene and naphthalene derivatives, heteroaromatic compounds such as ferrocene[232, furan, thiophene, selenophene[233,234], and cyclobutadiene iron carbonyl complexpSS] react with alkenes to give vinyl heterocydes. The ease of the reaction of styrene with sub.stituted benzenes to give stilbene derivatives 260 increases in the order benzene < naphthalene < ferrocene < furan. The effect of substituents in this reaction is similar to that in the electrophilic aromatic substitution reactions[236]. 

NAPHTHALENE DERIVATIVES] (Vol 16) a-Napthol-creatine phosphate-diacetyl... 

Sulfonation. Sulfonation of naphthalene with sulfuric acid produces mono-, di-, tri-, and tetranaphthalenesulfonic acids (see Naphthalene derivatives), ah of the naphthalenesulfonic acids form salts with most bases. Naphthalenesulfonic acids are important starting materials in the manufacture of organic dyes (15) (see Azo dyes). They also are intermediates used in reactions, eg, caustic fusion to yield naphthols, nitration to yield nitronaphthalenesulfonic acids, etc. 

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