Oligomerisation of linear 1-olefins using a chlorogallate(III) ionic liquid

A Lewis acidic chlorogallate(III) ionic liquid, 1-ethyl-3-methylimidazolium hepta-chlorodigallate(III), [C(2)mim][Ga2Cl7], was successfully used to oligomerise 1-pentene. The influence of temperature, time, catalyst concentration, and stirring rate on conversion and product distribution was modelled using a design of experiment (DoE) approach (chemometrics). The process was optimised for lubricant base oils production; the C20-C50 fraction (where Cn indicates the number of carbons in the oligomer) was maximised, while the heavier oligomer fraction (>C50) was minimised.

Micro-abrasion mechanisms of cast CoCrMo in simulated body fluids

The abrasion seen on some of the retrieved CoCrMo hip joints has been reported to be caused by entrained hard particles in vivo. However, little work has been reported on the abrasion mechanisms of CoCrMo alloy in simulated body environments. Therefore. this study covers the mapping of micro-abrasion wear mechanisms of cast CoCrMo induced by third body hard particles under a wide range of abrasive test conditions. This study has a specific focus on covering the possible in vivo wear modes seen on metal-on-metal (MoM) surfaces. Nano-indentation and nano-scratch tests were also employed to further investigate the secondary wear mechanisms-nano-scale material deformation that involved in micro-abrasion processes. This work addresses the potential detrimental effects of third body hard particles in vivo such as increased wear rates (debris generation) and corrosion (metal-ion release). The abrasive wear mechanisms of cast CoCrMo have been investigated under various wear-corrosion conditions employing two abrasives, SiC (similar to 4 mu m) and Al(2)O(3) (similar to 1 mu m), in two test solutions, 0.9% NaCl and 25% bovine serum. The specific wear rates, wear mechanisms and transitions between mechanisms are discussed in terms of the abrasive size, volume fraction and the test solutions deployed. The work shows that at high abrasive volume fractions, the presence of protein enhanced the wear loss due to the enhanced particle entrainment, whereas at much lower abrasive volume fractions, protein reduced the wear loss by acting as a boundary lubricant or rolling elements which reduced the abrasivity (load per particle) of the abrasive particles. The abrasive wear rate and wear mechanisms of the CoCrMo are dependent on the nature of the third body abrasives, their entrainment into the contact and the presence of the proteins. (C) 2009 Elsevier B.V. All rights reserved.

A '3-body' abrasion wear study of bioceramics for total hip joint replacements

The current study focuses on the effect of the material type and the lubricant on the abrasive wear behaviour of two important commercially available ceramic on ceramic prosthetic systems, namely, Biolox(R) forte and Bioloxl(R) delta (CeramTec AG, Germany). A standard microabrasion wear apparatus was used to produce '3-body' abrasive wear scars with three different lubricants: ultrapure water, 25 vol% new-born calf serum solution and 1 wt% carboxymethyl cellulose sodium salt (CMC-Na) solution. 1 mu m alumina particles were used as the abrasive. The morphology of the wear scar was examined in detail using Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM). Subsurface damage accumulation was investigated by Focused Ion Beam (FIB) cross-sectional milling and Transmission Electron Microscopy (TEM). The effect of the lubricant on the '3-body' abrasive wear mechanisms is discussed and the effect of material properties compared. (C) 2009 Elsevier B.V. All rights reserved.

Liquid coordination complexes: a new class of Lewis acids as safer alternatives to BF3 in synthesis of polyalphaolefins

Liquid coordination complexes (LCCs) are a new class of liquid Lewis acids, prepared by combining an excess of a metal halide (e.g. GaCl3) with a basic donor molecule (e.g. amides, amines or phosphines). LCCs were used to catalyse oligomerisation of 1-decene to polyalphaolefins (PAOs). Molecular weight distribution and physical properties of the produced oils were compliant with those required for low viscosity synthetic (Group IV) lubricant base oils. Kinematic viscosities at 100 °C of ca. 4 or 6 cSt were obtained, along with viscosity indexes above 120 and pour points below −57 °C. In industry, to achieve similar properties, BF3 gas is used as a catalyst. LCCs are proposed as a safer and economically attractive alternative to BF3 gas for the production of polyalphaolefins.

Oligomerisation process

This invention relates to base oils for lubricating compositions. In particular, the present invention provides a process for the selective oligomerisation of C5 to C 20 alpha-olefins to produce polyalphaolefin oligomers with a molecular weight distribution that is suitable for use in lubricant base oils.

Oligomerisation process

This invention relates to base oils for lubricating compositions. In particular, the present invention provides a process for the selective oligomerisation of C5 to C20 alpha-olefins to produce polyalphaolefin oligomers with a molecular weight distribution that is suitable for use in lubricant base oils.