Metalation naphthalene

Naphthalene is known to form a stable lithium dianion at -80°C in tetrahydrofuran (THP) at concentrations lower than 0.5 mol.I-1 (9-12). Unfortunately organolithium compounds are unable to polymerize oxirane (13). Naphthalene can also be metalation by sodium and potassium in THF but no experimental evidence for a dianion of naphthalene sodium or potassium is to be found. Although naphthalene metalation by sodium is thoroughly described ( , lU, 15), very few results about potassium are published (l6, "nT As the reducing power of the alkali metals decreases from lithium (Li/Li+ = 3 02v) to potassium (K/K+ -2.92v) and finally to sodium (Na/Na+ = 2.71v) (l8), it is attractive to study in more detail the naphthalene metalation by in the THF. 

There is a great similarity in the course of the naphthalene metalation by Li at -80°C on one hand and by at RT on the other hand. The titration of the carbanions formed (19) proves the presence of two anions per naphthalene only at naphthalene concentrations lower than 0.03 mol.l- for at RT (Table I) and... 

Naphthalene Metalation hy Potassium in THF at Room Temperature Naphthalene Carbanions ... 

Apart from the metal atom aggregation reactions described below, bis(arene)metal complexes of the early transition metals are resistant to ligand displacement The rings on the corresponding bis(naphthalene)metal species (41) are by, contrast, labile. Polymer-supported analogs of these naphthalene compounds with vanadium and chromium are known (42), but Ti atoms attack the polymer at the silicon ether linkage. These and other hybrid polymers can be further modified once the metal atom is incorporated. Thus a-methyl naphthalene is displaced from the hybrid organometallic polymer shown in Scheme 7 (43). 

KdisR. Ac+ are the dissociation constants of the ion pairs Rf Ac+ and R Ac+. Under suitable conditions, the equilibria (29)—(31) can be followed by spectro-photometric methods [167c, 169], There exist some very important specific reactions of the type shown in eqns. (29) and (30) which are poorly characterized. This concerns, for example, the electron transfer from naphthalene- metal+ (Szwarc initiator) to styrene or other monomers [see Chap. 3, eqn. (46)]. The rapid consecutive reactions of the styrene radical ion make a direct measurement of the equilibrium impossible. Indirect data are not reliable. 

Oxidation of 2-methyl naphthalene Metal salt and heteropolyacid 2-Methyl 1.4 naphthoquinone Kozhevnikov (1995)... 

Finally, it has been possible to obtain LEED patterns from films of molecular solids deposited on a metal-backing. Examples include ice and naphthalene [80] and various phthalocyanines [81]. (The metal backing helps to prevent surface charging.)... 

The catalyst is prepared by the reaction of sodium metal with naphthalen( and results in the formation of a radical ion ... 

Fig. 6. Dyes for WORM media phthalocyanine derivatives. The basic stmcture (12) of naphthalocyanine derivatives. Y = Si, Ge, Sn, Al, Ga, In, or a transition metal = ORj, OSiR R R, polymer. and represent substituents on the tings of the naphthalene system.

Fixed-Bed Vapor-Phase Oxidation of Naphthalene. A sihca gel or sihcon carbide support is used for catalyst involved in the oxidation of naphthalene. The typical naphthalene oxidation catalyst is a mixture of vanadium oxide and alkali metal sulfate on the siUca support. Some changes, such as the introduction of feed vaporizers, are needed to handle a naphthalene feed (14), but otherwise the equipment is the same. 

The addition product, C QHgNa, called naphthalenesodium or sodium naphthalene complex, may be regarded as a resonance hybrid. The ether is more than just a solvent that promotes the reaction. StabiUty of the complex depends on the presence of the ether, and sodium can be Hberated by evaporating the ether or by dilution using an indifferent solvent, such as ethyl ether. A number of ether-type solvents are effective in complex preparation, such as methyl ethyl ether, ethylene glycol dimethyl ether, dioxane, and THF. Trimethyl amine also promotes complex formation. This reaction proceeds with all alkah metals. Other aromatic compounds, eg, diphenyl, anthracene, and phenanthrene, also form sodium complexes (16,20). 

Naphthalene sodium prepared in dimethyl ether or another appropriate solvent, or metallic sodium dissolved in Hquid ammonia or dimethyl sulfoxide, is used to treat polyfluorocarbon and other resins to promote adhesion (138—140). Sodium, usually in dispersed form, is used to desulfurize a variety of hydrocarbon stocks (141). The process is most useful for removal of small amounts of sulfur remaining after hydrodesulfurization. 

Eriochrome Blue Black R (Palatine Chrome Black 6BN, Calcon, 3-hydroxy-4-(2-hydroxy-l-naphthylazo)naphthalene-l-sulfonic acid Na salt] [2538-85-4] M 416.4, pK2 7.0, pKj 13,5. Freed from metallic impurities by three pptns from aqueous soln by addn of HCl. The ppted dye was dried at 60° under vacuum. Indicator for complexometry of Al, Fe and 7i. 

The process of anionic polymerisation was first used some 60 or more years ago in the sodium-catalysed production of polybutadiene (Buna Rubbers). Typical catalysts include alkali metals, alkali metal alkyls and sodium naphthalene, and these may be used for opening either a double bond or a ring structure to bring about polymerisation. Although the process is not of major importance with the production of plastics materials, it is very important in the production of synthetic rubbers. In addition the method has certain special features that make it of particular interest. 

As previously described, a mixture of and J -octalins can be prepared by the reduction of naphthalene or Tetralin. Another route to this mixture is the dehydration of a mixture of 2-decalol isomers. This latter route has certain advantages in that one can avoid the handling of lithium metal and low-boiling amines. Moreover, 2-decalol is available commercially or can be prepared by the hydrogenation of 2-naphthol (5). In either case a comparable mixture of octalins is obtained, which can be purified by selective hydroboration to give the pure J -octalin (Chapter 4, Section III). 

Although the sulfone activated biphenyl and the ketone activated naphthalene moiety for the displacement polymerization have been reported by Attwood et al. [11], these were rediscovered by Cummings et al. [12] and Hergenrother et al. [13], respectively, for the synthesis of poly(aryl ethers). Recently, Singh and Hay [14] reported polymers containing 0-dibenzoyl benzene (1,2,3) moiety by reaction between bis(O-fluorobenzoyl) benzene or substituted benzene with bisphenates of alkali metal salt in DMAC as follows ... 

Under N2, clean Li metal (0.17 g, 25 mmol) was placed in a round-bottom flask with a solvent mixture of MeOH (3 mL) and pcntan-t-ol (17 mL). The mixture was heated under N, until the reaction with Li was complete. Then, naphthalene-2,3-dicarbonitrilc (2 g, 11 mmol) was added to the mixture which turned green-brown the mixture was refluxed for 3h. The brown powder, obtained after cooling and removal of the solvent under reduced pressure, was dissolved in anhyd acetone (20 mL) and then hexane (70 mL) was added. The green precipitate was separated from the brown solution by filtration. This purification by precipitation was repeated twice. The green precipitate was placed in a Soxhlet extractor and extracted for 3 h with acetone (200 mL) in order to separate the product from the insoluble metal-free species and LiOH. The acetone solution was evaporated down to a volume of 20 mL. The product precipitated after the addition of hexane (70 mL). This latter purification step was performed several times yield 1.29 g (64%). 

Treating naphthalene-2,3-dicarbonitrile with sodium 3-methylbut-l-oxide in 3-methylbutan-l-ol for five hours at reflux gives 2,3-naphthalocyanine 1, which, when stirred with methanol at room temperature, gives the metal-free 2,3-naphthalocyanine (2). 

Naphthalene-2,3-dicarbonitrile (0.89 g, 5 mmol) and (NH4)2Mo04 (0.002 g) were refluxed for 5 h in a solution of sodium 3-inethyIbut-l-oxide [made from Na (0.09 g) and anhyd 3-methylbutan-l-ol(IOOmL)J. Aftercoolingto80 C, the suspension was filtered and the precipitate was washed with MeOH. Forcomplete transformation of the disodium 2,3-naphthalocyanine (1) into the metal-free compound 2, the material was left for several h in MeOH at rt and then the precipitate was filtered and freed from impurities by extraction with MeOH and benzene yield 0.23 g (26%). 

Electron transfer reactions involving alkali metals are heterogeneous, and for many purposes it is desirable to deal with a homogeneous electron transfer system. It was noticed by Scott39 that sodium and other alkali metals react rapidly with aromatic hydrocarbons like diphenyl, naphthalene, anthracene, etc., giving intensely colored complexes of a 1 to 1 ratio of sodium to hydro-... 

Polymerization of ethylene oxide might be initiated by electron transfer process if metallic Na or Li is used as an initiator. On the other hand, initiation by sodium naphthalene involves not electron transfer but addition to naphthalene- ion. 

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