Nitro-2-methylnaphthalene

Fierz-David and Mannhart, Helv. Chim. Acta, 20, 1027 (1937). 

A solution of 142 g. (1.0 mole) of 2-methylnaphthalene in 220 g. of acetic acid is stirred vigorously and cooled to 0-45° while 58 g. of fuming nitric acid (sp. gr. 1.52) is added dropwise. The mixture is stirred at room temperature for 1 hour after completion of the addition and then is slowly heated to 80° over a period of 4-5 hours. The reaction mixture is cooled overnight in the refrigerator, and the precipitated solid is collected by filtration. Excess ice is added to the filtrate, and the precipitated solid is filtered. The combined solids are washed with dilute sodium carbonate solution and water and then 

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The most extensive work on the subject so far has been carried out by Brink and Shrieve [44]. The highest yield of 2-methyl-1-nitronaphthalene they obtained was 57% of the theoretical. This was produced by nitrating 2-methylnaphthalene at low temperatures (0-30°C) with a 70% excess of 70% nitric acid The other isomers appeared as a by-product oil. When using a 15% excess of a nitrating mixture composed of 25% HNOs, 55% H2S04 and 20% H20 the yield of 1-nitro-2-methylnaphthalene was also 57%. Dinitration took place when acetic anhydride was used. The product was in the form of a solid with m. p. 209-213°C. No determination of the structure of the dinitroproducts was carried out. 

Gas-phase absorption spectra for 1- and 2-nitronaphthalene are not available to us at this writing, but as a reasonable surrogate we may use that observed for 1-nitro-2-methylnaphthalene in ethanol solution (Lang, 1961-1971). These data are shown in figure IX-L-15. The cross sections at wavelengths within the troposphere are summarized in table IX-L-8. 

Nitrol. Early Brit plastic safety expl, patented by 0. Silberrad in 1912 (Ref 2). A typical formulation is Nitrol 10, highly. nitrated benzene hydrocarbons 20, collodion cotton 0.5, and AN 69.5%. Under the same name, 0. Silberrad took Brit and US patents on expl mixts contg Nitro-methylnaphthalene 20-25, oxidizer (nitrates, chlorates, perchlorates, etc) 50—60, collodion cotton 0—5 and woodmeal 0—5% (Ref 1)... 

Dinitro-1 -Methylnaphthalene, mp 14.2—43°, needles from ale. Prepn from 5-nitro-1-methyl-naphthalene by nitration on a steam bath using nitric (d 1.52g/cc) coned sulfuric acids in glac AcOH Acj O... 

X-Dinitro-1-Methylnaphthalene, mp 176°, brown plates from AcOH. Prepn from 4-nitro-1-methylnaphthalene by nitration in the cold with nitric acid (d 1.5g/cc)... 

Dinitro-2-Methylnaphthalener mp 131°. SI sol in ale AcOH. Prepn (together with 1,8-dinitro-2-methylnaphthalene) from l-nitro-2-methylnaphthalene by heating with coned nitric acetic acids on a w bath Refs 1) Beil 5, [466] 1635 2) V. 

As long ago as 1884, Schulze [38] examined the process of nitration of 2-methylnaphthalene with nitric and sulphuric acids and reported l-nitro-2-methylnaph-... 

A number of other authors have carried out the nitration of 2-methylnaphtha-lene, mainly as a step in the preparation of a new intermediate for dyes. Lesser, Glasser and Aczel [40] nitrated 2-methylnaphthalene in the presence of acetic acid and Vessely and Kapp [41] used nitric acid alone at low temperature (5-15°C). They obtained a 58% yield of l-nitro-2-methylnaphthalene and an oil which contained 4-Nitro-, 6-nitro- and 8-nitro-2-methylnaphthalenes. Vessely and his co-workers [42, 43] identified qualitatively most of the mononitro derivatives of 2-methylnaphthalene and their reduction products. 

X,XiTrinitr6-1-Methylnaphthalene, mp 180—81°, straw-yellow needles from CCI4. V si sol iri ale, appreciably sol in CCI4, chlf AcOH. Prepn from 4-nitro-l-methylnaphthalene by nitration with muted nitric-sulfuric acids Refs 1) Beil 5, (266) 2) R. Lesser A. 

OB to CO2 —85.04%, needles from glac AcOH, mp 262—63° (decomp). Sol in glac AcOH, acet, dioxane py si sol in benz, toluene, xylene amyl ale. Prepn from l-nitro-2-. methylnaphthalene by nitration using mixed acids of nitric (d 1.52g/cc), sulfuric (d 1.84 g/cc) oleum (20—25% SO3 free), and heating for one hour at 80° on a water bath. Two other isomers which do not decompose are prepd simultaneously viz, mp (I) 230° ... 

When 2-methylnaphthalene is nitrated, three isomeric mononitro derivatives are obtained. Upon vigorous oxidation one of these yields 3-nitro-l,2,4-benzenetricarboxylic acid, and the other two both yield 3-nitrophthalic acid. Give the names and structures of the original three isomeric nitro compounds. 

The particular value of the method is for converting methyl and polymethyl derivatives of polycyclic aromatic compounds into mono- and poly-carboxylic acids. For instance, 1-methylnaphthalene with a 42% excess of aqueous sodium dichromate solution in an autoclave at 240-250° gives 95% of 1-naphthoic acid in 18 h 2-methylnaphthalene with a 55% excess gives a 93% yield of 2-naphthoic acid the methyl group in fluoro-, bromo-, chloro-, nitro-, and methoxy-toluene as well as in xylenes and heterocycles can usually be oxidized smoothly to a carboxyl group. An excess of Na2Cr207 acts as a buffer and favors smooth reaction. With 1.5 moles of Na2Cr207 the reaction occurs in accord with the equation ... 

Table I. Ratio of the Most Abundant a-Nitro Isomer to the Sum of All Other Nitro Isomers Formed in the Nitration of Naphthalene and Some Methylnaphthalenes...

The reaction is rather complex it follows uncatalyzed and/or one or two catalyzed pathways. Furthermore the reaction order with respect to amine varies with solvent. For instance in the reaction of 4 -nitrophenyl 3-nitro cinnamate at 20 °C the amine has the order 1 in acetonitrile, 1-1-2 in 1,2-dichloroethane, 2-1-3 in benzene and 1H-2-1- 3 in 1-methylnaphthalene. In general the number of amine molecules required for the reaction increases with decreasing solvent polarity. The Hammett q constant diminishes in the same trend in polar medium q is high, in less polar but complexing (TT-donor) solvent it is lower. 

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