Naphthalene sodium Method

This method is suitable only for small scale (S mmol or less) preparations of these diphosphenes because of the difficulties involved in removing larger quantities of naphthalene from the product. 

The corresponding aryl-substituted diphosphene, (2,4, d-t-BusQHi) P=P-(2,4,6-t-Bu3C6H2), mp 175-176 C, is made by the same method in 72% yield using (2,4,6-t-Bu3C6H2)PCl2 (1.74g, 5.0mmol). If necessary, additional purification can be carried out by recrystallization from hexane at -10 C. 

Houben-Weyl Methoden der Organischen Cheme, Vol. 13/1, Thieme Verlag Stuttgart 1970, p. 381. 

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Weber, P. L. Buck, D. R. Capillary Electrophoresis A Past and Simple Method for the Determination of the Amino Acid Composition of Proteins, /. Chem. Educ. 1994, 71, 609-612. This experiment describes a method for determining the amino acid composition of cyctochrome c and lysozyme. The proteins are hydrolyzed in acid, and an internal standard of a-aminoadipic acid is added. Derivatization with naphthalene-2,3-dicarboxaldehyde gives derivatives that absorb at 420 nm. Separation is by MEKC using a buffer solution of 50 mM SDS in 20 mM sodium borate. 

Acid-cataly2ed hydroxylation of naphthalene with 90% hydrogen peroxide gives either 1-naphthol or 2-naphthiol at a 98% yield, depending on the acidity of the system and the solvent used. In anhydrous hydrogen fluoride or 70% HF—30% pyridine solution at — 10 to + 20°C, 1-naphthol is the product formed in > 98% selectivity. In contrast, 2-naphthol is obtained in hydroxylation in super acid (HF—BF, HF—SbF, HF—TaF, FSO H—SbF ) solution at — 60 to — 78°C in > 98% selectivity (57). Of the three commercial methods of manufacture, the pressure hydrolysis of 1-naphthaleneamine with aqueous sulfuric acid at 180°C has been abandoned, at least in the United States. The caustic fusion of sodium 1-naphthalenesulfonate with 50 wt % aqueous sodium hydroxide at ca 290°C followed by the neutralization gives 1-naphthalenol in a ca 90% yield. 

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. 

The method illustrates the ability of the sodium hydride-dimethylformamide system to effect the alkylation of aromatic sulfonamides under mild conditions and in good yield. The method appears to be fairly general. The submitters have prepared N,N-diethyl- and N,N-di- -butyl- >-toluenesulfonamide as well as 2-(/ -tolyIsuIfonyl)benz[/]isoindoline from 2,3-bis-(bromomethyl)naphthalene, and 1 %-tolylsulfony])pyrrolidine from 1,4-dichIorobutane the yield of purified product exceeded 75% in each case. 

Another method is amination with a polyamine and an aldehyde [1567]. The formulation also contains sodium carbonate, sodium phosphate, sodium sulfite, sodium metasilicate, or naphthalene sulfonate. The sulfonated or sulfomethyl-ated aminated lignin shows less retardation (shorter thickening time) than a sulfonated or sulfomethylated lignin without the attached amine. 

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. 

The purification procedures to be applied depend on the monomer, on the expected impurities, and especially on the purpose for which the monomer is to be employed, e.g., whether it is to be used for radical polymerization in aqueous emulsion or for ionic polymerization initiated with sodium naphthalene. It is not possible to devise a general purification scheme instead the most suitable method must be chosen in each case from those given below. A prerequisite for successful purification is extreme cleanliness of all apparatus (if necessary, treating with hot nitrating acid and repeatedly thorough washing with distilled water). 

Other methods that use 55 anions as precursor for the synthesis of fullerene-derivatives usually involve chemical formation of the anion. Alkylation of 55 has been accomplished, e.g. by reduction with propanethiol and potassium carbonate in DMF [91,92], sodium methanethiolate in acetonitrile [93], the naphthalene radical anion in benzonitrile[94], potassium naphthalide [95] or simply with zinc [96]. 

The chemical removal of water can be done in several ways. For anionic polymerisations it is customary to rinse all the glassware repeatedly with a solution of sodium naphthalide which reacts with water to form naphthalene and NaOH, both of which are adequately soluble in the usual solvent tetrahydrofuran (THF) at the low concentrations used. This method, however, requires that the whole reactor assembly be detachable from the vacuum line so that it can be tilted around for the sodium naphtalide solution to reach all parts of the system. Care If much water is to be removed and the volume of the purging solution is too small, some NaOH may be precipitated ). 

Tetrathionaphthalenes and their corresponding selenium analogues are synthesized by reaction of tetrachloro-naphthalenes 197 with / -generated sodium disulfide or with sodium diselenide (Equation 132). The yields of the sulfur analogues were found to be dependent on the method of disulfide generation (Table 14) <2001HAC287>. 

Naphthalene 1,2-oxide (45) can be prepared by treatment of bromohydrin 46 with sodium methoxide in THF. Cyclization and dehydrobromination are achieved in a single pot.28 By this method, the non-K-region epoxide phenanthrene 1,2-oxide (47) and the bay-region oxide phenanthrene 3,4-oxide (48) have also been prepared.28 The syntheses of homobenzene analog 49 and... 

Another common method for the preparation of benzene and naphthalene epoxides is by introduction of double bonds into the dihydro precursors. This is generally achieved by bromination-dehydrobromination. Thus unsubstituted benzene oxide-oxepin (86 96) can be obtained by dehydrohalogenation of the dibromocyclohexane epoxide 99, using a basic amine or sodium methoxide in ether.53... 

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