Naphthalene sodium

Usually prepared on the large scale by caustic soda fusion of sodium naphthalene-1-sulphonate, but can also be obtained by high-temperature alkaline digestion of... 

Prepared commercially by NaOH fusion of sodium naphthalene-2-sulphonate. 

Sodium naphthalene [25398-08-7J and other aromatic radical anions react with monomers such as styrene by reversible electron transfer to form the corresponding monomer radical anions. Although the equihbtium (eq. 10)... 

Aromatic radical anions, such as lithium naphthalene or sodium naphthalene, are efficient difunctional initiators (eqs. 6,7) (3,20,64). However, the necessity of using polar solvents for their formation and use limits their utility for diene polymerization, since the unique abiUty of lithium to provide high 1,4-polydiene microstmcture is lost in polar media (1,33,34,57,63,64). Consequentiy, a significant research challenge has been to discover a hydrocarbon-soluble dilithium initiator which would initiate the polymerization of styrene and diene monomers to form monomodal a, CO-dianionic polymers at rates which are faster or comparable to the rates of polymerization, ie, to form narrow molecular weight distribution polymers (61,65,66). 

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). 

Carbanions ia the form of phenyllithium, sodium naphthalene complex, sodium acetyHde, or aromatic Grignard reagents react with alkyl sulfates to give a C-alkyl product (30—33). Grignard reagents require two moles of dimethyl sulfate for complete reaction. 

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. 

Treatment with two equivalents of tert-butyl hypochlorite and subsequent reduction with sodium/naphthalene. 

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. 

The polymerization of 2-furaldehyde by sodium and sodium naphthalene reported by Kulakov and Kamenskii151 did not produce structure 32, but rather some resinous oligomeric materials formed through the interactions of the furan ring with the formyl group. 

Reaction of organic halides with sodium naphthalene... 

On the basis of reaction-product structures, it might be expected that the reactions of organic halides with sodium naphthalene (Scheme 9) might resemble mechanistically the reactions of organic halides with lithium alkyls. CIDNP studies have shown that they are in fact quite different, in particular in the mechanism by which polarization occurs. The observations are as follows (Garst et al., 1970). 

This type of polarization appears to be general in such systems and it has been proposed that it arises because of T i-S mixing. An interesting and important addif ional observation comes from a study of the reaction of isopropyl chloride with sodium naphthalene in a field of 60 G. Net emission in the products is predicted for T i-S mixing and multiplet polarization for Tq-S mixing. Since no multiplet polarization can be detected, it would seem that Tq-S mixing is suppressed in this system (Garst et al., 1971). Presumably, the naphthalene radical anion... 

Net F-polarization (A at 56-4 MHz) has been observed during the reaction of p-fluorobenzyl chloride with sodium naphthalene in tetra-hydrofuran solution to give p, p -difluorobibenzyl (Rakshys, 1971). The spin selection is believed to take place within a radical pair of the -------------------------------F... 

Sodium alkylamides can also be generated in situ by reacting the amine with sodium naphthalene in THF [207, 208]. This procedure has been used for the condensation of secondary amines with different 1,3-dienes to give high yields of monoalky-lated products without formation of 1 2 telomers. In the case of primary amines, mixtures of mono- and dialkylated products are obtained together with unidentified... 

The fluid loss and thickening time characteristics of the cement slurry is altered, either by increasing the molecular weight of the lignin by cross-linking with formaldehyde or epichlorohydrin or by adding agents such as sodium sulfite, sodium metasilicate, sodium phosphate, and sodium naphthalene sulfonate. 

In contrast with the behaviour of typical vinylphosphonic acid derivatives, the carbon-carbon double bond in the 1,2-oxa-phospholene (167) is remarkably unreactive towards a broad spectrum of reagents including electrophiles, most epoxidizing and organometallic reagents, as well as to dipolar addition reactants. Exceptional reagents are, however, N-bromoacetamide (NBA), ozone, dimethyllithiumcuprate, and sodium-naphthalene. 

Due to the commercial availability of Cp2TiCl2, its reduction and subsequent treatment with CO represents one of the most direct routes to Cp2Ti(CO)2 (1). An early example of this method was reported by Calderazzo et al. whereby Cp2TiCl2 was first reduced by sodium naphthalene at 25°C in THF for 24 hours (16). The resulting green titanocene, p.-(rf i75-fulvalene)-di-/i-hydrido-bis(cyclopentadienyltitanium) (17-22), was then treated with 1 atm of CO in toluene for 4 hours at 20°C. However, this procedure proved inefficient for the production of 1 since only 10% of the required amount of CO for complete conversion was consumed. 

Solvents. water was doubly-distilled from an all-Pyrex apparatus. All the other solvents were supplied by BDH and mostly used as supplied, except that tetrahydrofuran (THF) was first distilled from lithium "aluminium hydride and then from a sodium/naphthalene mixture (the green coloration of the latter being indicative of the absence of water). 

The precipitated silica (J. Crosfield Sons) was heated in vacuo at 120° for 24h. before use. Two grades of surface areas 186 and 227 m g l (BET,N2), were used during this project. Random copolymers, poly(methyl methacrylates) and polystyrene PS I were prepared by radical polymerization block polymers and the other polystyrenes were made by anionic polymerization with either sodium naphthalene or sodium a methylstyrene tetramer as initiator. The polymer compositions and molecular weights are given in Table I. 

Only a few publications have appeared in which for the synthesis of reactive microgels other monomers were used than 1,4-DVB or EDMA. Hiller and Funke studied the anionic polymerization of 1,4-diisopropenylbenzene (1,4-DIPB) by n-BuLi in 1,2-dimethoxyethane and by sodium naphthalene in THF [231]. 

The first reported zirconacydopentadiene was 2,3,4,5-tetraphenyl-l-zirconacyclopenta-diene (la), prepared from two molecules of diphenylacetylene and a low-valent zircono-cene [3]. The low-valent zirconocene spedes was produced by the reaction of Cp2ZrCl2 with sodium/naphthalene (Eq. 2.1). 

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