Tetrahydronaphthalene, from naphthalene

Tetrahydronaphthalene is produced by the catalytic treatment of naphthalene with hydrogen. Various processes have been used, eg, vapor-phase reactions at 101.3 kPa (1 atm) as well as higher pressure Hquid-phase hydrogenation where the conditions are dependent upon the particular catalyst used. Nickel or modified nickel catalysts generally are used commercially however, they are sensitive to sulfur, and only naphthalene that has very low sulfur levels can be used. Thus many naphthalene producers purify their product to remove the thionaphthene, which is the principal sulfur compound present. Sodium treatment and catalytic hydrodesulfuri2ation processes have been used for the removal of sulfur from naphthalene the latter treatment is preferred because of the ha2ardous nature of sodium treatment. 

Naphthalene is reduced to 1,4-dihydronaphthalene by sodium and alcohol. Isomerization of this product to 3,4-dihydronaphthalene occurs with sodamide in liquid ammonia. Tetrahydronaphthalene (tetralin) is formed from naphthalene by sodium in amyl alcohol or by reduction with nickel-aluminum alloy and aqueous alkali. Catalytic hydrogenation of naphthalene can be stopped at the tetralin stage over copper chromite, Raney nickel, or alkali metal catalysts. cis-Decahydronaphthalene is produced by high-pressure hydrogenation of tetralin over Adams catalyst, whereas a mixture of cis- and trans-decalins is obtained from naphthalene under the same conditions. ... 

Knox et al. [108] studied the retention characteristics of 54 aromatic hydrocarbons (benzene— hexamethylbenzene and selected isomers, toluene—decyl-benzene and selected isomers, indane, indene, tetrahydronaphthalene, and naphthalene—fluorene and terphenyls) on three Cjg columns using 70/30, 80/20, and 90/10 (w/w) methanol/water mobile phases, (Note that the v/v ratios are q)proxi-mately 74/26, 83/17 and 92/8, respectively.) Capacity factors were tabulated for each column and each mobile phase composition when the analytes eluted with a k = 40. The t values ranged from 1 (benzene) to 39 (1,2,3-triisopropylbenzene) for 70/30 and 0.2 (benzene) to 20 ( -tridecylbenzene) for 90/10 methanol/ water. 

Tetrahydronaphthalene [119-64-2] (Tetralin) is a water-white Hquid that is insoluble in water, slightly soluble in methyl alcohol, and completely soluble in other monohydric alcohols, ethyl ether, and most other organic solvents. It is a powerhil solvent for oils, resins, waxes, mbber, asphalt, and aromatic hydrocarbons, eg, naphthalene and anthracene. Its high flash point and low vapor pressure make it usehil in the manufacture of paints, lacquers, and varnishes for cleaning printing ink from rollers and type in the manufacture of shoe creams and floor waxes as a solvent in the textile industry and for the removal of naphthalene deposits in gas-distribution systems (25). The commercial product typically has a tetrahydronaphthalene content of >97 wt%, with some decahydronaphthalene and naphthalene as the principal impurities. 

MNN is obtained in 3—5% yield by the nitration of naphthalene and is present at this level in coml MNN. It is best prepd by indirect methods for example, by the removal of an amino group from an appropriately substituted nitro-naphthylamine. The amine is treated with Na nitrite and acid to form the diazonium salt which is replaced with a H atom by redn with EtOH (Ref 7). It may also be prepd by treatment of 6-nitro-l, 2,3,4-tetrahydronaphthalene with Br to form a dibromo compn (probably the 1,4-isomer), followed by removal of two moles of H bromide by distn in the presence of base (Ref 10). 2-Naphthalenediazonium fluoroborate... 

Partial reduction of polyarenes has been reported. Use of boron trifluoride hydrate (BF3 OH2) as the acid in conjunction with triethylsilane causes the reduction of certain activated aromatic systems 217,262 Thus, treatment of anthracene with a 4-6 molar excess of BE3 OH2 and a 30% molar excess of triethylsilane gives 9,10-dihydroanthracene in 89% yield after 1 hour at room temperature (Eq. 120). Naphthacene gives the analogously reduced product in 88% yield under the same conditions. These conditions also result in the formation of tetralin from 1-hydroxynaphthalene (52%, 4 hours), 2-hydroxy naphthalene (37%, 7 hours), 1-methoxynaphthalene (37%, 10 hours), 2-methoxynaphthalene (26%, 10 hours), and 1-naphthalenethiol (13%, 6 hours). Naphthalene, phenanthrene, 1-methylnaphthalene, 2-naphthalenethiol, phenol, anisole, toluene, and benzene all resist reduction under these conditions.217 Use of deuterated triethylsilane to reduce 1-methoxynaphthalene gives tetralin-l,l,3-yielding information on the mechanism of these reductions.262 2-Mercaptonaphthalenes are reduced to 2,3,4,5-tetrahydronaphthalenes in poor to modest yields.217 263... 

In another paper from the Jackson Laboratories of the du Pont Company (Calcott et al., 34) there is reported a repetition of some of the reactions of Simons and Archer, as well as additional ones. Mono-, di-, and 1,2,4,5 tetraisopropylbenzene were obtained from propylene and benzene both l -chloro-i-butylbenzene and di-(l/-chloro)-d-butylben-zene were obtained from 3-chloro-2-methyl-propene-l and benzene p-f-butyltoluene and di-i-butyltoluene were obtained from diisobutylene and toluene tetraisopropylnaphthalene was obtained from propylene and naphthalene naphthyl-stearic acid was obtained from oleic acid and naphthalene mixed isopropyltetrahydronaphthalene was obtained from propylene and tetrahydronaphthalene 2,4,6-triisopropylphenol was obtained from propylene and phenol a mixture of monoisopropylated m-cresols was obtained from propylene and wi-cresol and di-(s-hexyl)-diphenyl oxide was obtained from hexene-3 and diphenyl oxide. 

The starting material for the 1,2-disubstituted tetrahydro-naphthalenes was 5,6,7,8-tetrahydro-2-naphthol. This compound was converted in low yield to the known Via by the Reimer-Tiemann reaction. VI6 and Vic both were prepared from 1-bromo-2-methoxy-5,6,7,8-tetrahydronaphthalene. Although VI6 was prepared according to the method of O Farrell et al. [3], we obtained a much higher yield,... 

The reactivity, site of attack, and stereochemistry of the reactions of a variety of nucleophiles (oxygen, sulfur, nitrogen, organometallic) with anti-and syn-naphthalene 1,2 3,4-dioxides have been studied recently.159 In most cases, di- or tetrasubstituted tetrahydronaphthalene products arising from attack at C-l and C-4 positions in the anti mode are produced. These isomeric diepoxides are excellent intermediates for the preparation of a number of difficulty accessible 1,4-disubstituted naphthalene derivatives. 

Cyclohexadienol was prepared by Rickborn in 1970 from reaction of the epoxide of 1,4-cyclohexadiene with methyl lithium.100 A hydrate of naphthalene, 1-hydroxy-1,2-dihydro-naphthalene was prepared by Bamberger in 1895 by allylic bromination of O-acylated tetralol (1-hydroxy-l,2,3,4-tetrahydronaphthalene) followed by reaction with base.101 Hydrates of naphthalene and other polycylic aromatics are also available from oxidative fermentation of dihydroaromatic molecules, which occurs particularly efficiently with a mutant strain (UV4) of Pseudomonas putida.102,103 The hydrates are alcohols and they undergo acid-catalyzed dehydration to form the aromatic molecule by the same mechanism as other alcohols, except that the thermodynamic driving force provided by the aromatic product makes deprotonation of the carbocation (arenonium ion) a fast reaction, so that in contrast to simple alcohols, formation of the carbocation is rate-determining (Scheme 6).104,105... 

Reactive solvents dissolve coal by active interaction. Such solvents are usually hydrogen donors (e.g., tetralin, 1,2,3,4-tetrahydronaphthalene) and their chemical composition is affected appreciably during the process. Again, using tetralin as the example, the solvent is converted to the aromatic counterpart (in this case, naphthalene) and the products from the coal can vary in composition, depending on the reaction severity and the ratio of the solvent to the coal. In addition, the extracts differ markedly in properties from those obtained with degrading solvents. 

From its chemistry, it is very clear that naphthalene is aromatic but perhaps a little less so than benzene itself. For example, naphthalene can easily be reduced to tetralin (1,2,3,4-tetrahydronaphthalene) which still contains a benzene ring. Also, in contrast to benzene, all the bond lengths in naphthalene are not the same. 

Figure 1.1 Variations in catalytic activity as a function of the degree of leaching with NiAb (O) and C02AI9 ( ) (a) hydrogenation of cyclohexanone (1 ml) in f-BuOH (10 ml) at40°C and atmospheric hydrogen pressure over 0.08 g of catalytic metal (b) hydrogenation of naphthalene (3 g) to tetrahydronaphthalene in cyclohexane (10 ml) at 60°C and 8.5 1.5 MPa H2 over 0.08 g of catalytic metal (c) hydrogenation of benzene (15 ml) in cyclohexane (5 ml) at 80°C and 7.5 2.5 MPa H2 over 0.08 g of catalytic metal. (From Nishimura, S. Kawashima, M. Inoue, S. Takeoka, S. Shimizu, M. Takagi, Y.Appl. Catal. 1991, 76, 26. Reproduced with permission of Elsevier Science.)...

The use of DBN made possible for the first time the synthesis of naphthalene-1,2-oxidc (4) from 4-bromo-l,2-epoxy-l,2,3,4-tetrahydronaphthalene (3) ... 

The formation of methyl 2-methyl-1,2,3,4-tetrahydro-naphthalene-2-carboxylate can be explained by reactions similar to that of 1,2,3,4-tetrahydronaphthalene-2-carbonitrile from the pyrolysis of poly(styrene-co-acrylonitrile), and it is shown below ... 

The observations that the pH-independent reactions of deuterium-labeled 5-met-hoxyindene oxide and 6-methoxy-1,2,3,4-tetrahydronaphthalene-1,2-oxide show significant primary kinetic deuterium isotope effects for the ketone-forming reactions, whereas the pH-independent reactions of deuterium-labeled naphthalene oxide and benzene oxide do not, are quite puzzling. Clearly, more work needs to be done to fully understand why transition-state structures for rearrangement of arene oxides to phenols differ from those for rearrangement of benzylic epoxides to ketones. 

A striking illustration of the relative stability of the benzenoid and of a hydroaromatic ring is afforded by the oxidation of tetra-hydro-naphthalene with air. The preponderating product is phthalic anhydride, with little or no tetrahydronaphthalic acid present, showing the selectively complete destruction of the non-benzenoid ring. Data on the oxidation of tetrahydronaphthalene are available from the work of Maxted,J7 and are shown in Table XLI. 

Bromine adducts in which not all the C=C bonds are saturated are more easily prepared from polycyclic aromatic hydrocarbons. Thus 1,2,3,4-tetra-bromo-l,2,3,4-tetrahydronaphthalene is obtained by brominating pure naphthalene in anhydrous CC14 at 0° with irradiation (30% yield)134 or in CC14 at room temperature with irradiation and addition of peroxide (ascaridole) (12% yield).135 Anthracene adds bromine in CS2 at 0°, giving 9,10-dibromo-9,10-dihydroanthracene,136,137 and phenanthrene in ether138 or carbon disulfide139 gives 9,10-dibromo-9,10-dihydrophenanthrene when warmed, these two products pass into 9-monobromo derivatives by loss of HBr. 

When the conjugated systems are not monocyclic, the situation becomes a little less clear. Naphthalene, for example, has ten electrons but you can also think of it as two fused benzene rings. From its chemistry, it is very clear that naphthalene has aromatic character (it does substitution reactions) but is iess aromatic than benzene itself. For example, naphthalene can easily be reduced to tetralin (1,2,3,4-tetrahydronaphthalene), which still contains a benzene ring. Also, in contrast to benzene, all the bond lengths in naphthalene are not the same. 1,6-Methano[10]annulene is rather like naphthalene but with the middle bond replaced by a methylene bridging group. This compound is almost flat and shows aromatic character. 

To a cold solution (-6°C) of 12.8 g naphthalene (0.10 mol) in 100 mL w-propylamine, 30 g ethylenediamine (0.5 mol) and 44.4 g r-butanol (0.6 mol), was added 3.5 g lithium (0.5 mol) portionwise in small pieces. The solution was warmed to 20°C and maintained by the addition of lithium. Afterl.5 h, the reaction mixture was poured over 150 g ice and 100 mL water and then extracted with ether. The ether was washed with water, brine, and evaporated under reduced pressure to give 12.2 g of a colorless solid that was triturated with methanol, filtered, and dried to give crude product. Recrystallization from 50 mL methanol gave 9.8 g 1,4,5,8-tetrahydronaphthalene, in a yield of 74%, with a purity of 93% by GLPC. 

Tetrahydro-naphthalene (cont) tetrahydronaphthalene, technically pure 60 60 3 Not resistant >8 >5 <50 Hostalen HMW Hoechst Celanese Specimen 50X25X1 mm (2X1X0.04 in) from press-molded sheets to DIN 53455... 

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