Comparison of hydrocracking reactivities of coal extracts from a flowing-solvent reactor, a mini-bomb and a pilot plant

Zhang, Shengfu; Xu, Bin; Moore, S. A.; Herod, Alan A.; Kandiyoti, R.

doi:10.1016/0016-2361(95)00284-7

Cited by 39 publications

(29 citation statements)

References 14 publications

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“…Hydrocracked product was prepared in a microbomb reactor at 460 °C (60 min, 190 bar H 2 pressure), in the presence of a supported NiMo/Al 2 O 3 catalyst with tetralin as donor solvent. Both samples have been described in detail elsewhere. − …”

Section: Methodsmentioning

confidence: 99%

“…Both samples have been described in detail elsewhere. [20][21][22][23] Mass Spectrometry. A Bio Ion 20 252 Cf-plasma desorption, time-of-flight mass spectrometer was used to obtain molecular mass distributions of the samples.…”

Section: Methodsmentioning

confidence: 99%

“…These observations suggest that intensities at the high-mass limit of complex samples, such as coal-derived materials, may be significantly underestimated or remain altogether unobserved. In the case of a coal tar pitch, enhancement of high-mass signal could be achieved by fractionation. , …”

Section: Introductionmentioning

confidence: 99%

“…The present study has compared responses of PD-MS and LD-MS to identical samples, in order check the validity of findings from the two methods against one another. The two pairs of samples selected for the comparison were (i) a coal extract and its hydrocracked product , and (ii) the pyridine-soluble and -insoluble fractions of a coal tar pitch. ,,, Within each pair, previous work by size exclusion chromatography and by MALDI-MS had indicated significant differences between the high-mass contents of the two samples.…”

Section: Introductionmentioning

confidence: 99%

“…In the case of a coal tar pitch, enhancement of high-mass signal could be achieved by fractionation. 19,20 One distinguishing feature between MS techniques used in attempts to characterize coal-derived mixtures pertains to the particular sequence of evaporation ionization events. MS-based experience, to date, suggests that techniques where ionization occurs after thermal evaporation of sample molecules, e.g., GC-MS, heated probe MS, LC-MS, and FIMS, usually show lower mass ranges compared to techniques where ionization is thought in the main to precede and to assist desorption: FAB, FD, LD-MS, and PD-MS. Of these, the two types of instrument which have given the highest MM distributions among MS-based techniques have been PD-MS and LD-MS.…”

Section: Introductionmentioning

confidence: 99%

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Large Molecular Mass Materials in Coal-Derived Liquids by ²⁵²Cf-Plasma and Matrix-Assisted Laser Desorption Mass Spectrometry

Domin

Lázaro

et al. 1998

Energy Fuels

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The paper compares responses of 252 Cf-plasma desorption MS (PD-MS) and matrix-assisted laser desorption (MALDI) MS to identical samples. The two pairs of samples selected for the comparison were known from previous work to differ significantly in their high mass contents. MALDI-MS showed large differences in MM distributions within both pairs of samples. The PD-MS data showed a degree of similarity between one pair of samples (pyridine soluble/insoluble fractions of a coal tar pitch); for the second pair (a coal extract and its hydrocracked product), trends from the two MS techniques agreed closely. The MM range observed by PD-MS was somewhat narrower, extending to between 3000 and 5000 u. Significant differences within pairs of samples were observed by SEC and by UV-fluorescence spectroscopy, providing somewhat closer agreement with the MALDI spectra. The two MS instruments differ in two important respects: the ionization system (i.e., plasma vs laser desorption) and the maximum available ion extraction voltage: 30 kV for the MALDI-MS instrument and 15 kV for the PD-MS. The comparison of plasma vs laser desorption mass spectroscopy could not therefore take place at high ion extraction voltages. Work at up to 30 kV in the MALDI instrument indicated better sensitivity to highmass materials at higher ion extraction voltages. The qualitative similarity of results from the two MS techniques is nevertheless apparent; the range of MMs observed in PD-MS as well as in MALDI-MS were, furthermore, far larger than those reported by any MS technique, to date.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Large Molecular Mass Materials in Coal-Derived Liquids by ²⁵²Cf-Plasma and Matrix-Assisted Laser Desorption Mass Spectrometry

Domin

Lázaro

et al. 1998

Energy Fuels

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Matching average masses of pitch fractions of narrow polydispersity, derived from matrix‐assisted laser desorption ionisation time‐of‐flight mass spectrometry, with the polystyrene calibration of SEC

Islas

Suelves

Millán

et al. 2003

J of Separation Science

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Matching average masses of pitch fractions of narrow polydispersity, derived from matrix-assisted laser desorption ionisation time-of-flight mass spectrometry, with the polystyrene calibration of SEC A coal tar pitch has been fractionated by preparative and analytical size exclusion chromatography (SEC) to provide narrow time-elution fractions, expected to have relatively low molecular dispersities. The fractions were characterised by analytical SEC, by UV-fluorescence spectroscopy, and by laser-desorption MS and by MALDI-MS using sinapinic acid as matrix. The MALDI spectra were evaluated by measuring the peak-intensity mass, M p , and by calculating number (M n ) and weight (M w ) average masses. The high mass limits of the spectra were determined by three methods based on (i) truncating the spectrum when the signal fell below 5 times the standard deviation of signal at the instrument limit, (ii) taking the upper mass as defined by a minimum slope of the spectrum from baseline, and (iii) taking all of the high mass signal as from sample. The laser desorption spectra were evaluated by M p values only; the results below m/z 1,000 were in excellent agreement with the polymer calibration. The MALDI mass spectra gave a good fit between M p values below m/z 3,000 and the calibration of SEC by polymers. Working with M p gave better results than the M n and M w values from Method (i). Results from Methods (ii) and (iii) were significantly worse. Reasons for the lack of agreement between results above m/z 3,000 by MALDI and above m/z 1,000 by LD-MS have been discussed.

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The use of nonpolar matrices for matrix‐assisted laser desorption/ionization mass spectrometric analysis of high boiling crude oil fractions

Robins

Limbach

2003

Rapid Comm Mass Spectrometry

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Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) with nonpolar matrices has been investigated for its applicability to the characterization of atmospheric resid crude oil fractions. The data obtained by use of nonpolar matrices was compared with that from polar matrices as well as from direct LDI-MS and field ionization mass spectrometry. Nonpolar matrices, such as anthracene or 9-cyanoanthracene, yield only a single radical molecular cation upon LDI. Thus, no interfering matrix-related ions are present during the MALDI-TOFMS analysis of the crude oil sample. Nonpolar matrices yield molecular mass distributions from linear mode MALDI-TOFMS that are comparable to distributions found with LDI-MS. An advantage of nonpolar matrices is the increased production of analyte ions, which allows reflectron mode MALDI-TOFMS to be performed. Nonpolar matrices are also shown to be less sensitive to solvent and sample preparation conditions than conventional polar matrices. These results suggest that nonpolar matrices may be favorable alternatives to more traditional polar or acidic matrices commonly used in the MALDI mass spectral characterization of crude oil related samples.

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Comparison of hydrocracking reactivities of coal extracts from a flowing-solvent reactor, a mini-bomb and a pilot plant

Cited by 39 publications

References 14 publications

Large Molecular Mass Materials in Coal-Derived Liquids by ²⁵²Cf-Plasma and Matrix-Assisted Laser Desorption Mass Spectrometry

Large Molecular Mass Materials in Coal-Derived Liquids by ²⁵²Cf-Plasma and Matrix-Assisted Laser Desorption Mass Spectrometry

Matching average masses of pitch fractions of narrow polydispersity, derived from matrix‐assisted laser desorption ionisation time‐of‐flight mass spectrometry, with the polystyrene calibration of SEC

The use of nonpolar matrices for matrix‐assisted laser desorption/ionization mass spectrometric analysis of high boiling crude oil fractions

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Comparison of hydrocracking reactivities of coal extracts from a flowing-solvent reactor, a mini-bomb and a pilot plant

Cited by 39 publications

References 14 publications

Large Molecular Mass Materials in Coal-Derived Liquids by 252Cf-Plasma and Matrix-Assisted Laser Desorption Mass Spectrometry

Large Molecular Mass Materials in Coal-Derived Liquids by 252Cf-Plasma and Matrix-Assisted Laser Desorption Mass Spectrometry

Matching average masses of pitch fractions of narrow polydispersity, derived from matrix‐assisted laser desorption ionisation time‐of‐flight mass spectrometry, with the polystyrene calibration of SEC

The use of nonpolar matrices for matrix‐assisted laser desorption/ionization mass spectrometric analysis of high boiling crude oil fractions

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Product

Resources

About

Large Molecular Mass Materials in Coal-Derived Liquids by ²⁵²Cf-Plasma and Matrix-Assisted Laser Desorption Mass Spectrometry

Large Molecular Mass Materials in Coal-Derived Liquids by ²⁵²Cf-Plasma and Matrix-Assisted Laser Desorption Mass Spectrometry