Solid-state Mechanochemical Reaction Research Articles

Solid-state mechanochemical synthesis of ferrocene

Abstract Solid-state mechanochemical reactions of iron(II) chloride with cyclopentadienides of alkaline metals or thallium, which lead to the formation of ferrocene, were studied. The dependence of the yield of the product on the parameters of mechanical loading for the reaction with cyclopentadienylthallium was determined.

The Solid-State Mechanochemical Reaction of Fullerene C60

The solid-state mechanochemical reaction of fullerene C60 by the use of a high-speed vibration milling technique has been applied to the nucleophilic addition of an organozinc reagent to C60, [4+2] cycloaddition of C60 with condensed aromatic hydrocarbons, 1,3-dipolar addition of C60 with organic azides, and dimerization of C60.

Particularities of C60 Transformations at 1.5 GPa

The high-pressure states of C60 fullerene corresponding to the 1.5 GPa isobaric section of its p,T diagram in the 293−1073 K temperature range were investigated by X-ray diffraction and IR and Raman spectroscopies. It was shown that increasing the treatment temperature of C60 at quasihydrostatic pressure changes the nature of the polymerization products. The IR and Raman spectra of the high-pressure materials obtained at 423 K are similar to the spectra of the dumb-bell-shaped C60 dimer synthesized in a solid-state mechanochemical reaction of C60 with potassium cyanide by Wang et al.1 It can be concluded that this dumb-bell-shaped dimer is the main structural unit forming the low-pressure polymerization product. So, on further temperature increase, the dimer phase becomes unstable and transforms into the “low-pressure” orthorhombic polymerized phase of C60 which, in turn, transforms into the tetragonal polymerized phase at temperatures above ∼723 K. Depolymerization of the polymerized phases at temperatur...

Mechanochemical Synthesis and Characterization of the Fullerene Dimer C120

The bulk synthesis of the [2 + 2] dimer of fullerene C60 was achieved by the solid-state mechanochemical reaction of C60 with KCN by the use of a high-speed vibration milling (HSVM) technique. This reaction took place also by the use of potassium salts such as K2CO3 and CH3CO2K, metals such as Li, Na, K, Mg, Al, and Zn, and organic bases such as 4-(dimethylamino)- and 4-aminopyridine. Under optimum conditions, the reaction afforded only the dimer C120 and unchanged C60 in a ratio of about 3:7 (by weight) regardless of the reagent used. The dimer C120 was fully characterized by IR, UV−vis, 13C NMR, and TOF MS spectroscopies, cyclic voltammetry, and differential scanning calorimetry. Comparison of the IR and 13C NMR spectral data of C120 with those reported for all-carbon C60 polymers implied that the [2 + 2] dimer C120 represents the essential subunit of these polymers. The dimer C120 underwent facile dissociation into two C60 molecules by heat, HSVM treatment, exposure to room light, or electrochemical re...

Mechanochemical processing of refractory pyrite

Mechanochemical reactions are those which are initiated by the application of a mechanical force. In recent times it has been shown that solid state mechanochemical reactions can be initiated by milling the reactants in a high energy ball mill — a process known as mechanical milling. Oxidation/reduction reactions have been shown to occur at room temperature during mechanical milling, and this has led to the idea that it may be possible to refine metallic ores via room temperature mechanochemical processes. In this study, it has been found that pyrite (FeS 2) can be mechanochemically processed in a high energy ball mill. Pyrite is the most common sulfide host for gold, and in refractory pyrite samples gold is encapsulated in the pyrite matrix, so this matrix must be broken down prior to cyanidation. X-ray diffraction, Mössbauer spectroscopy and thermal analysis techniques have shown that pyrite can be oxidised mechanochemically, with the sulfur retained as a sulfate without the production of sulfur dioxide gas. Potential exists for this process to form the basis for an economically viable, environmentally friendly process for the treatment of refractory pyritic gold ores.

Mechanochemical synthesis of ultrafine zinc sulfide particles

The synthesis of nano-sized ZnS particles by the mechanochemical solid-state reaction of ZnCl 2 and CaS has been investigated using X-ray diffraction, TEM and DTA measurements. Mechanical milling of ZnCl 2 and CaS resulted in the formation of ∼ 500 nm ZnS particles containing aggregates of 12 nm crystallites. The addition of 71 vol% CaCl 2 as a diluent to the reactants resulted in the formation of separated 16 nm particles of ZnS. Using mechanically alloyed CaS (10–50 nm particle size) enabled the synthesis of isolated ZnS particles 7–9 nm in size. The effects of milling time and subsequent annealing on particle size have also been investigated.

Synthesis and X-ray structure of dumb-bell-shaped C120

The discovery and large-scale synthesis of fullerenes have aroused interdisciplinary interest in these closed-cage molecules1,2,3,4,5,6. C60 can be photopolymerized into a form in which the cages are thought to be linked by cyclic C4 units in a [2 + 2] cycloaddition7, provoking theoretical studies of the C60 dimer8,9,10,11,12,13,14,15, the smallest subunit of such a polymer. The C60 dimers C120O (refs 16, 17), C121H2( ref. 17) and C120O2(ref. 18) have been reported, in which the two C60molecules are linked by, respectively, a furan group, a cyclopentane ring and a cyclobutane ring plus two oxygen bridges; but the simplest dimer, C120linked by a cyclobutane ring alone, has not so far been observed. We now report that this dumb-bell-shaped molecule can be synthesized by a solid-state mechanochemical reaction of C60 with potassium cyanide. Our X-ray structural analysis shows that the C4 ring connecting the cages is square rather than rectangular—the latter is predicted theoretically8,9,13,14,15. The dimer dissociates cleanly into two C60 molecules on heating or one-electron reduction, but in the gas phase during mass-spectrometric measurements it undergoes successive loss of C2 units, shrinking to even-numbered fullerenes such as C118 and C116 in a sequence similar to that seen for other large fullerenes19,20.

Formation of water soluble complexes of : solid-state reaction between tertiary amines and

Water soluble complexes of have been prepared on solid-state mechano-chemical reaction between and tertiary amines (hexamine, DABCO) at room temperature . The product is characterized by x-ray diffraction and FTIR methods. It is presumably due to the charge transfer interactions between electron affinic and electron rich tertiary amines.