Detailed characterisation of polyalphaolefins and their branched structures using multi‐pulse NMR techniques

Kapur, G. S.; Sarpal, A. S.; Sarin, Rakesh K.; Jain, S. K.; Srivastava, S. P.; Bhatnagar, A. K.

doi:10.1002/jsl.3000150303

Cited by 15 publications

(9 citation statements)

References 12 publications

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Section: Resultsmentioning

confidence: 99%

“…The hydrocarbon mobility and characteristics of liquids can be explained by the measurements of molecular dynamics parameters such as relaxation time (mobility) (T 1 ), reorientation correlation time and diffusion coefficient (D). 2,4,16 The molecular mobility parameters of various methyl branched structure describe motion of the normal and isoparaffins including long alkyl chain attached to aromatics or naphthenes. In order to account for the contribution of each towards the molecular dynamics of a system, diffusion coefficients (D) of the base oil samples as such were determined by the application of 1 H-PGSE techniques.…”

Section: Molecular Diffusion Measurementmentioning

confidence: 99%

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Correlation of structure and properties of groups I to III base oils

Sarpal

Sastry

Bansal

et al. 2012

Lubrication Science

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The understanding of the relationship between molecular structure and viscosity–temperature behaviour of a lubricant system is a subject of considerable importance. The quantitative distribution and types of different classes of hydrocarbons such as aromatics, paraffins (normal and iso) and naphthenes determine the physico‐chemical behaviour of a lubricant system. The study of molecular structure and molecular alignment of hydrocarbons constituting a lubricant helps in the development of lubricating oil with desired physico‐chemical properties. The present study highlights the application of nuclear magnetic resonance spectroscopic technique for deriving detailed hydrocarbon structural features present in API groups II and III base oils produced through catalytic hydrocracking/isodewaxing processes. The viscosity–temperature and viscosity–pressure properties, such as viscosity index, pour point, elastohydrodynamic film thickness and cold cranking simulator viscosity, were determined. The structural features of these base oils such as various methyl branched structures of isoparaffins and branching index, which are characteristics of high performance molecules, were correlated with the above‐mentioned properties to explain their physico‐chemical properties, particularly low temperature properties. The molecular dynamics parameters such as diffusion coefficient and T1 relaxation times estimated from the nuclear magnetic resonance spectral studies have provided sufficient evidence for the dependence of these properties on these high performance molecules present in various types of methyl structures of isoparaffins of groups II and III base oils compared with conventional group I base oils. Results are explained on the basis of molecular structural differences of hydrocarbons present in these base oils and diffusion measurement studies. On the basis of the studies, molecular engineering concept for the designing of a high performance base oil molecule is proposed. Copyright © 2012 John Wiley & Sons, Ltd.

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Section: Resultsmentioning

confidence: 99%

Section: Molecular Diffusion Measurementmentioning

confidence: 99%

Correlation of structure and properties of groups I to III base oils

Sarpal

Sastry

Bansal

et al. 2012

Lubrication Science

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“…The composition (acid/polyol parts) of the four synthetic base oils used for the studies is provided in Table 2. The PAO6 was a hydrocarbon (richer in paraffins and isoparaffins; Kapur, et al (5)) and the remaining four samples were synthetic esters of different chemistries. PES11 was a pentaerythritol ester of mixed acids (mainly heptanoic acid, octonoic acid, and decanoic acid), PE507 was a pentaerythritol ester of …”

Section: Characterization Of Base Oilsmentioning

confidence: 99%

Molecular Dynamics of Synthetic-Based Lubricant System by Spectroscopic Techniques—Part 1

Sarpal

Sastry

Kumar

et al. 2013

Tribology Transactions

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This article describes the structure-property relationships of synthetic pentaerythritol polyol esters (PEE) and polyalphaolefins (PAO) as established by the diffusion and mobility measurement and tilt angle results obtained by nuclear magnetic resonance (NMR) and infrared (IR) spectroscopic techniques, respectively. The diffusion coefficients (D) were found to be dependent on the molecular structure, alkyl chain length, shape and size, hydrodynamic volume, and alignment of the molecules in a lubricant system constituting these base stocks. The viscosity-temperature and viscosity-pressure properties such as viscosity index (VI), pour point (PP), elastohydrodynamic (EHD) film thickness, pressure-viscosity coefficient (α), hydrodynamic volume, and radius are explained on the basis of the variation in D with temperature and tilt angle on the smooth surfaces. The study has enabled us to propose a molecular structure of a synthetic molecule that can be molecularly engineered to have high-performance physicochemical properties.

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“…Most often, decene-1, the raw material from low-molecular oligomers (dimers, trimers) are obtained in the first step. Low-kinematic viscosity poly-α-olefins (2-10 mm 2 /s at 100°C, PAO-2, PAO-4, PAO-6, PAO-8, PAO-10) are produced in oligomerization catalysed by BF 3 . The presence of a proton donor catalyst is also required.…”

Section: Introductionmentioning

confidence: 99%

“…Distillation (third step) leads to products having specific values of kinematic viscosity at 100°C. Distillation may also be accomplished before the hydrogenation (step II) [1][2][3][4][5][6]. The composition and properties of lowkinematic viscosity PAOs are presented in Table I.…”

Section: Introductionmentioning

confidence: 99%

Chromatographic and non‐chromatographic characterization of poly‐α‐olefins

Voelkel

Fall²

2007

J of Synthetic Lubrication

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Both chromatographic and non-chromatographic techniques were used in the characterization and identification of poly-α-olefins. Synthetic base oils, although produced from the same raw material, exhibit different physicochemical properties. Their mutual miscibility and behaviour in final engine oils may be predicted from data collected through classical physico-chemical analysis, simulated distillation chromatography as well as inverse gas chromatography.

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Detailed characterisation of polyalphaolefins and their branched structures using multi‐pulse NMR techniques

Cited by 15 publications

References 12 publications

Correlation of structure and properties of groups I to III base oils

Correlation of structure and properties of groups I to III base oils

Molecular Dynamics of Synthetic-Based Lubricant System by Spectroscopic Techniques—Part 1

Chromatographic and non‐chromatographic characterization of poly‐α‐olefins

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