Detailed characterisation of isomers present in polyalphaolefin dimer and the effect of isomeric distribution on bulk properties

Abstract

This study has been conducted with the aim to gain detailed insight into the chemical nature of polyalphaolefin dimer (PAO dimer, C 20 H 42 ). By using gas chromatography/mass spectrometry, a large number of isomers the complex mixture consists of has been identified; the variety of structural motifs ranges from a homologous series of almost linear vicinal dimethyloctadecanes to highly branched isomers such as 6,7-dibutyldodecane. However, the mixture is characterised by the presence of isomers, which exhibit an intermediate degree of branching. Furthermore, a generally applicable protocol has been established to determine the relative content of these isomers. This protocol has then been applied to analyse samples from different PAO dimer batches, and a correlation between isomeric distribution and bulk properties, namely the viscosity-temperature behaviour, has been found. It turns out that the viscosity of PAO dimer depends less on temperature if the amount of weakly branched and almost linear isomers increases.

Excitation energies and ionization potentials at high electric fields for molecules relevant for electrically insulating liquids

“…DMOD has the potential to be used as a base insulating liquid because of its desirable physical properties such as high viscosity indices, good thermal and oxidative stabilities, and low toxicity. 41 GTB is an ester molecule with some advantages as a base insulating liquid. Ester liquids are used as insulating liquids in high voltage applications.…”

Investigations on calcium carboxylate and sulfonate additive incompatibilities in a preservation oil

“…It turns out that the base oil composition does not underlie significant fluctuations; only the isomeric distribution within the PAO fraction may vary. However, these variations should not influence the base oil's properties and are therefore not taken into consideration …”

A Study on the Control of Microstructures of Polyalphaolefins via Cationic Polymerization

“…Chromatographic studies of hydrogenated dimer show that over 50 different isomers are generated during the reaction. 13,14 Moreover, NMR analyses of dimer and other higher oligomers have shown that all of the skeletal rearrangement may occur at the dimerization stage, and much analytical work has focused on the dimer fraction. 15 A more detailed reaction mechanism for the origin of multiple skeletal isomers in the polymerization of 1-decene has been reported by J. C. Gee et al…”