Erling Rytter

Structure and stability of solid and molten complexes in the MgCl2-AlCl3 system

Abstract A visual determination of the phase diagram of the MgCl2-AlCl3 system reveals the formation of two intermediate compounds. One of these compounds is MgAl2Cl8 crystallizing with a monoclinic unit cell, space group I2/c, with dimensions a = 12.873(1)A, b = 7.8959(7)A, c = 11.617(1)A, β = 92.348(8)° and z = 4. The two crystal modifications of anhydrous magnesium chloride and the lattice parameters of aluminium chloride have been reexamined. Lattice energies for α- and β-MgCl2 have been measured, respectively, as 661(1) and 646(4) kcal mol−1. The liquidus curve on the acidic side has been used to estimate the activity of aluminium chloride. Fourier-transform IR spectra of melts with compositions ranging from 0 to 30 mol% MgCl2 have been interpreted in terms of Al2Cl6, strongly perturbed Al2Cl7− and AlCl4− entities. In particular, the tetrachloroaluminate ion acts as both a tri- and a bidentate ligand towards Mg2+. Neutral species, e.g. Mg(AlCl4)2 and Mg(Al2Cl6)(AlCl4)Cl, dominate in the melt. Ab initio molecular-orbital calculations have been performed to obtain a better understanding of the Mg2+ —d AlCl4− interaction.

Spectral evidence for a 2:1 complex between titanium tetrachloride and ethyl benzoate

Abstract Infrared spectra of codeposited ethyl benzoate with excess titanium tetrachloride at 80 K revealed a novel 2:1 complex, where the inorganic entity is proposed to be a dimeric, triple bridged titanium tetrachloride unit. The ester is complexed to one of the octahedral titanium units through the carbonyl group. Compared to the 2:2 complex there are νc=o ν α-C-Oand νTi-O shifts of -40/-47, +4/+24 and +16/17 cm−1, depending on which of the 18O-carbonyl or d5-ethyl isotopic congeners is considered.

FTIR spectroscopy of ethyl benzoate-titanium tetrachloride complexes with application to supported Ziegler-Natta catalysts

X-ray studies revealed a strongtrans-influence in titanium tetrachloride-ethyl benzoate complexes. From FTIR spectra, a very strong complexation is found in a 2∶1 complex and in a surface complex on magnesium chloride supported Ziegler-Natta catalysts. In both cases the ester is proposed to betrans to a bridging chlorine.

Band distortions in emission and specular reflection FTIR spectroscopy

General equations for emittance and reflectance of multilayer systems are given. It is demonstrated that band distortions can be avoided by application of the appropriate working equations. An opaque (thick) sample is employed as a reference.

Vibrational analysis and FTIR spectra of seven isotopic congeners of ethyl benzoate including18O carbonyl and ether labelled esters

FTIR spectra of seven isotopic congeners of ethyl benzoate are fitted to a force field with a standard deviation of less than 7 cm−1. The field has been transferred to ethyl anisate and an equimolar titanium tetrachloride-ethyl benzoate complex with encouraging success. The band at 1280cm−1 is definitely assigned as mainly anα-C-O stretch.

FTIR reflection spectra and structure of molten chloroaluminates containing alkaline earth chlorides or oxides

FTIR reflection spectra of molten chloroaluminates containing alkali earth chlorides showC2v andC3v perturbations of AlCl4−. The splitting ofv3(F2) is proportional to the ionic potential of the counterion. The observation of anion-cation stretching vibrations allows the strength of the interaction to be evaluated. Molten NaAl2OCl5 is assumed to contain the Al4O2C1102− ion.