title: An analytical method for lubricant quality control by NIR spectroscopy.
abstract: The excellent compatibility of polyol esters (POEs) with general fluids coolants such as CO(2) and non-chlorinated coolants (e.g. hydrofluorocarbons, HFCs) in terms of solubility, miscibility and chemical stability has fostered their use as lubricants by the refrigeration industry. The most widely used POEs bases consist of esters of polyalcohols - such as pentaerythritol, dipentaerythritol and neopentylglycol - with mixtures of carboxylic acids of 4-10 carbon atoms. Their thermophysical properties (viscosity mainly) are crucial with a view to producing efficient lubricants for specific applications. Usually, POE formulations, which usually contain several bases, are characterized in terms of global indices. In this work, we developed a methodology based on NIR spectroscopy for the characterization and analysis of lubricant formulations. The products, including lubricant bases and lubricant formulations, are characterized by reference to two spectral libraries that are used to identify as the starting lubricant bases as well as the lubricant formulations. It has been proposed to build libraries in cascade for the differentiation of lubricant formulations without and with low content in additives. Once the identification of the formulation is applied PLS multivariate models are used to determine the components of a lubricant formulation and its viscosity.
authors.affiliation: Department of Chemistry, Faculty of Sciences, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain.
authors.forename: David
authors.initials: D
authors.lastname: Zamora
authors.forename: Marcelo
authors.initials: M
authors.lastname: Blanco
authors.forename: Manel
authors.initials: M
authors.lastname: Bautista
authors.forename: Rufí
authors.initials: R
authors.lastname: Mulero
authors.forename: Miquel
authors.initials: M
authors.lastname: Mir