Liquid ferrocene

Metal cyclopentadienyls have already proved to be of considerable technical interest. According to investigations carried out mainly in the United States, ferrocene is able to bring about smokeless combustion of fuel oil when added in amounts of 0.05% (1). Its use as an oil additive for jet motors and as an antiknock has also been proposed. Liquid ferrocene is said to have advantages as a thermally stable heat-transfer medium. Dicyclopentadienyl nickel also has possible applications, and dicyclopentadienyl titanium-dichloride has been studied in association with aluminum alkyls for the polymerization of ethylene (15, 133, 134). Finally, the carbonyl CHsC5H4Mn(CO)3 has been considered as a fuel additive in conjunction with tetraethyl lead (0). Other information is given in the patent literature (40). 

Operating conditions Solid and liquid samples were dissolved in benzene, carbon tetrachloride or chloroform. Neat liquid ferrocene could also be injected directly without dilution into the flash vapourizer by means of a microsyringe. Chloroform was the best solvent for most of the compounds, although the hydroxymethyl-substituted ferrocenes were more soluble in benzene than in chloroform. Saturated or nearly saturated solutions were used in most instances, and sample sizes ranged from 0.1 to 10 yl. 

The methods of preparation of ferrocene have been reviewed by Pauson and by Fischer. Ferrocene has been made by the reaction of ferric chloride with cyclopentadienylmagnesium bromide, by the direct thermal reaction of cyclopentadiene with iron metal, by the direct interaction of cyclopentadiene with iron carbonyl, by the reaction of ferrous chloride with cyclopentadiene in the presence of organic bases such as diethyl-amine, by the reaction of ferrous chloride with sodium cyclo-[lentadienide in liquid ammonia, and from cyclopentadiene and... 

Singer and co-workers have investigated the acylation reactions of ferrocene in ionic liquids made from mixtures of [EMIMJI and aluminium(III) chloride (Scheme 6.1-5) [9, 10]. The ionic liquid acts both as solvent and as source of the Friedel-Crafts catalyst. In mildly acidic (X(A1C13) > 0.5 [EMIM]I/A1C13, the monoacetylated ferrocene was obtained as the major product. In strongly acidic [EMIM]I/AlCl3 X(A1C13) = 0.67 the diacylated ferrocene was the major product. Also, when R = alkyl, the diacetylated product was usually the major product, but for R = Ph, the monoacetylated product was favored. 

The burning rates of standard aluminized hydrocarbon binder composite proplnts may be increased significantly not only with ferrocene derivatives but also with compatible carborane-type burning rate additives. However, most ferrocene derivatives are volatile solids or liquids which have a tendency to evaporate from the proplnt during storage, thereby degrading ballistic performance. Rudy (Ref 71) minimized this problem by the use of polynuclear ferrocene... 

Capacitance and interfacial tension measurements were used to study the interface between Hg and mixtures of acetone + nitromethane.330 The potential was measured against an SCEin H20 and corrected for the liquid junction potential by measuring the half-wave potential of the ferrocene-... 

Mesomorphic dendrimers containing electroactive units have potential for construction of dendrimer based molecular switches. Deschenaux et al. reported [154] the synthesis and liquid-crystalline properties of a novel dendrimer containing six mesomorphic ferrocene units. Apart from exhibiting a broad enantiotropic smectic A phase as determined by polarized optical microscopy, DSC, and XRD studies, thermogravimetry revealed the excellent thermal stability of the macromolecule. 

Since the solubility of long-chain alkenes is higher in ionic liquids than in water, there is much interest in finding effective ionic liquid catalysts for the hydroformylation reaction. Bis-phosphines have proved to be particularly useful in hydroformylation reactions and a bis-phosphine with a charged cobaltocenium backbone, analogous to l,l/-bis(diphenylphosphino)ferrocene (dppf), has been developed specifically for use in ionic liquid hydroformylation reactions [26], In combination with [Rh(CO)2(acac)], the 1, I -bis(diphenylphosphino)cobaltocenium hexafluorophosphate ligand dissolved in [bmim][PF6] effectively catalyses the hydroformylation of 1-octene as shown in Scheme 8.11. 

Fig. 11.18 shows experimental results concerning the frichon sensihvity of mixtures of AP parhcles and catalysts.Iil The AP parhcles are trimodal mixtures with diameters of 200 pm (33%), 35 pm (33%), and 5 pm (34%). Catocene (C27H32pe2) and ferrocene (CjoHjoFe) are both liquid organic compounds with iron atoms in their molecular structures and carborane is a liquid compound that contains boron atoms.Ii] The physicochemical properhes of -hexyl carborane are shown in Table 11.7. These catalysts are used to increase the burning rate of AP pyrolants. 

Carbazole will react with 1 or 2 mol of ferrocene in hot decalin in the presence of aluminium-aluminium chloride producing crystalline derivatives in which either one or both" of the benzene rings is linked to iron, 25 and 26, respectively. The sandwich compound 25 was deprotonated to 27 with sodamide in liquid ammonia. A chromium carbonyl complex 28... 

Scholz and Hasse [377] have shown that crystals of metallic silver can be grown at liquid/liquid interfaces (water with AgNOs -octanol with ferrocene). Depending on the reactants concentrations in both phases, silver crystallized in the form of (1) wires (whiskers with radii from about 50 nm to 50 pm) growing into the organic phase (2) Christmas treelike deposits at the interface and even (3) extremely smooth films of silver. 

Solid or liquid organometallic compounds such as ferrocene and its various derivatives, iron (III) acetyl acetonate, metal chelates etc. 

Butacene 800 is a liquid resin based on HTPB grafted with a ferrocene derivative in the chain. 

The reaction of ferrocene and formaldehyde in either concentrated sulfuric acid or liquid hydrogen fluoride, followed by reduction, produces a compound containing two ferrocenyl and two methylene groups (57, 98, 123). After several incorrect assignments had been proposed for the structure of this condensation product, Rinehart and coworkers showed by an unequivocal synthesis that the product was 1,2-diferrocenylethane (XIX) (104). The mechanism of the reaction presumably involves the initial formation of ferrocenylcarbinol (XX) followed by ionization in the strongly acidic medium to the ferrocenylmethyl-carbonium ion (XXI). Conversion to radical ion XXII followed by dimerization and subsequent reduction produces the product. 

In the previous section, we demonstrated the micrometer droplet size dependence of the ET rate across a microdroplet/water interface. Beside ET reactions, interfacial mass transfer (MT) processes are also expected to depend on the droplet size. MT of ions across a polarized liquid/liquid interface have been studied by various electrochemical techniques [9-15,87], However, the techniques are disadvantageous to obtain an inside look at MT across a microspherical liquid/liquid interface, since the shape of the spherical interface varies by the change in an interfacial tension during electrochemical measurements. Direct measurements of single droplets possessing a nonpolarized liquid/liquid interface are necessary to elucidate the interfacial MT processes. On the basis of the laser trapping-electrochemistry technique, we discuss MT processes of ferrocene derivatives (FeCp-X) across a micro-oil-droplet/water interface in detail and demonstrate a droplet size dependence of the MT rate. 

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