STRUCTURAL CHARACTERIZATION OF SOLID n-PARAFFIN COMPONENTS DERIVED FROM MUKTA CRUDE OIL

Khan, H. U.; Sharma, Rajesh; Nautiyal, S. P.; Agrawal, K. M.; Schmidt, P. W.

doi:10.1080/10916460008949880

Cited by 13 publications

(7 citation statements)

References 2 publications

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“…To address this issue, different methods are currently used to extract and analyze n-alkanes in samples containing a UCM. One of them, applied to complex mixtures found in sediments, petroleum crude, and petroleum-derived fractions, is urea adduction (3)(4)(5)(6). It was originally thought that urea adduction was specific to n-alkanes but many exceptions are now known (7).…”

Section: Introductionmentioning

confidence: 99%

“…To address this issue, different methods are currently used to extract and analyze n -alkanes in samples containing a UCM. One of them, applied to complex mixtures found in sediments, petroleum crude, and petroleum-derived frac tions, is urea adduction ( − ). It was originally thought that urea adduction was specific to n -alkanes but many exceptions are now known ().…”

Section: Introductionmentioning

confidence: 99%

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n-Alkane Profiles of Engine Lubricating Oil and Particulate Matter by Molecular Sieve Extraction

Caravaggio

Charland

Macdonald

et al. 2007

Environ. Sci. Technol.

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As part of the Canadian Atmospheric Fine Particle Research Program to obtain reliable primary source emission profiles, a molecular sieve method was developed to reliably determine n-alkanes in lubricating oils, vehicle emissions, and mobile source dominated ambient particulate matter (PM). This work was also initiated to better calculate carbon preference index values (CPI: the ratio of the sums of odd over even n-alkanes), a parameter for estimating anthropogenic versus biogenic contributions in PM. n-Alkanes in lubricating oil and mobile source dominated PM are difficult to identify and quantify by gas chromatography due to the presence of similar components that cannot be fully resolved. This results in a hump, the unresolved complex mixture (UCM) that leads to incorrect n-alkane concentrations and CPI values. The sieve method yielded better chromatography, unambiguous identification of n-alkanes and allowed examination of differences between n-alkane profiles in light (LDV) and heavy duty vehicle (HDV) lubricating oils that would have been otherwise difficult. These profile differences made it possible to relate the LDV profile to that of the PM samples collected during a tunnel study in August 2001 near Vancouver (British Columbia, Canada). The n-alkane PM data revealed that longer sampling times result in a negative artifact, i.e., the desorption of the more volatile n-alkanes from the filters. Furthermore, the sieve procedure yielded n-alkane data that allowed calculation of accurate CPI values for lubricating oils and PM samples. Finally, this method may prove helpful in estimating the respective diesel and gasoline contributions to ambient PM.

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Section: Introductionmentioning

confidence: 99%

“…To address this issue, different methods are currently used to extract and analyze n -alkanes in samples containing a UCM. One of them, applied to complex mixtures found in sediments, petroleum crude, and petroleum-derived frac tions, is urea adduction ( − ). It was originally thought that urea adduction was specific to n -alkanes but many exceptions are now known ().…”

Section: Introductionmentioning

confidence: 99%

n-Alkane Profiles of Engine Lubricating Oil and Particulate Matter by Molecular Sieve Extraction

Caravaggio

Charland

Macdonald

et al. 2007

Environ. Sci. Technol.

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“…Solid paraffin is mainly composed of C 18 –C 30 straight-chain alkanes, and it also contains isomeric alkanes, cycloalkanes, and a small number of aromatics. Meanwhile, liquid paraffin is mainly composed of normal alkanes with a shorter carbon chain (C 16 –C 20 ). , …”

Section: Resultsmentioning

confidence: 99%

“…Thus, solid paraffin can form simple compounds readily in the production of paraffin compared to liquid paraffin. 37 Figure 6a shows eight organic pollutants that were present in both solid and liquid paraffin samples and could act as precursors of PCDD/Fs. Polycyclic aromatic hydrocarbons are typically used as precursors when investigating the formation of PCDD/Fs in thermochemical reactions.…”

Section: Mass Fractions and Congener Group Profiles Ofmentioning

confidence: 99%

Occurrence and Formation Mechanism of PCDD/Fs and SCCPs in Chlorinated Paraffin Products

He,

Liu,

Gao

et al. 2023

Environ. Sci. Technol.

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Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and short-chain chlorinated paraffins (SCCPs) can be formed during the production of chlorinated paraffins (CPs). Detection and accurate quantification of PCDD/Fs in CPs are challenging because of their matrix complexity. Therefore, the occurrence and formation mechanisms of PCDD/Fs from CPs have not been studied extensively in the past. In this study, 15 commercial samples including solid and liquid CPs were collected in 2022 from China. The average ΣSCCP concentrations detected in the solid and liquid CPs were 158 and 137 mg/g, respectively. The average International Toxic Equivalent (I-TEQ) values of 2,3,7,8-PCDD/F in solid and liquid CPs were 15.8 pg I-TEQ/g and 15.0 pg I-TEQ/g, respectively. The solid and liquid CPs had different predominant congener groups for SCCPs and PCDD/Fs. Possible formation routes for the generation of PCDD/Fs were analyzed by screening precursors in paraffin and laboratory-scale thermochemical experiments of CPs. The transformation between 2,3,7,8-PCDD/Fs and non-2,3,7,8-PCDD/Fs was recognized by calculating the successive chlorination preference. The first reported occurrence of PCDD/Fs in CP commercial products indicated that exposure to CPs and downstream products might be an assignable source of PCDD/F emission, which is of great significance to further explore the control factors of PCDD/Fs in the whole life cycle of CPs.

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“…A possible explanation for this apparent inconsistency is that the concentrations of less-stable alkanes were “frozen” at relatively high levels, because of the kinetics barriers, after they evolved due to thermal cracking of larger crude molecules. NMR analyses for crude oils and their distillates showed that the tertiary aliphatic carbon accounts for ∼10% of the total carbon and the branch index (CH 3 /CH 2 ) of saturates ranged from 0.1 to 0.3. ,, We limited the isoparaffins in the middle distillate to have, at most, three branches with a maximum branch length of C4, and no quaternary carbon was allowed. Similar rules were made by Mizan and Klein in their study of catalytic hydroisomerization, to rationalize the product yield distributions.…”

Section: Methodsmentioning

confidence: 99%

Derivation of Molecular Representations of Middle Distillates

Ring

Liu

2005

Energy Fuels

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The molecular representation of hydrocarbon mixtures is critical to the advanced kinetics modeling of refining conversion processes; however, the achievement of such a representation is considered a significant challenge. The isomeric lump in a homologous series sets the analytical limit in analytical characterization of middle and heavy distillates. This paper proposes a new procedure for de-lumping detailed analytical information generated using a gas chromatography−field-ionization mass spectrometry (GC−FIMS) method into a molecular representation. As a result, concentration distributions of the various molecules in the sample of interest are calculated. This paper presents a deterministic computer-assisted procedure that automatically (i) generates hydrocarbon molecules according to literature-based set of rules, (ii) selects the hydrocarbon molecules that are most thermodynamically stable (likely to exist), (iii) optimizes the three-dimensional geometry of those molecules and calculates their thermodynamic properties, and (iv) calculates the concentration distributions of those molecules. A separate validation calculation involves (i) prediction of the physical properties for pure hydrocarbons using quantitative structure−property relationship (QSPR) correlations; and (ii) prediction of bulk physical properties of this mixture using the calculated concentrations, properties of its pure hydrocarbon components, and suitable mixing rules. This procedure was applied to find molecular representations of five middle-distillate samples and the results were validated through the estimation and comparison of such simulated and measured physical properties as density, refractive index, and simulated distillation curves (the latter of which are used as a consistency check). Good agreement was observed between the predicted and measured properties for all five middle-distillate samples. This agreement validates the molecular characterization algorithm, at least for the purpose of bulk property prediction in middle distillates.

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STRUCTURAL CHARACTERIZATION OF SOLID n-PARAFFIN COMPONENTS DERIVED FROM MUKTA CRUDE OIL

Cited by 13 publications

References 2 publications

n-Alkane Profiles of Engine Lubricating Oil and Particulate Matter by Molecular Sieve Extraction

n-Alkane Profiles of Engine Lubricating Oil and Particulate Matter by Molecular Sieve Extraction

Occurrence and Formation Mechanism of PCDD/Fs and SCCPs in Chlorinated Paraffin Products

Derivation of Molecular Representations of Middle Distillates

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