Asphaltenes as model compounds of the UIBs/AIBs detected in various astrophysical objects. Part 1 – Petroleum asphaltenes carbonization

<div>Here, we newly propose the structure of protoaculeine B, an N-terminal moiety of the marine peptide toxin aculeine B, as possessing the cis-disubstituted tetrahydro-beta-carboline framework. We prepared two truncated model compounds that lack long-chain polyamine by one-step Pictet-Spengler reaction of tryptophan, and compared the NMR and mass spectra and chemical reactivity with those of natural protoaculeine B. The synthetic models reproduced the profiles of the natural product well, which was conclusive for the structural revision.</div>

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Lignin to Value-Added Chemical Synthesis

Current Analytical Chemistry ◽

10.2174/1573411016666200108152127 ◽

2020 ◽

Vol 16 ◽

Author(s):

Mahdieh Sharifi ◽

Ramyakrishna Pothu ◽

Rajender Boddula ◽

Inamuddin

Keyword(s):

Ionic Liquids ◽

Lignocellulosic Biomass ◽

Academic Research ◽

Power Saving ◽

Value Added ◽

Glycerol Ether ◽

Model Compounds ◽

Lignin Model Compounds ◽

Biomass Activity ◽

Lignin Model

Background: There is a developing demand for innovation in petroleum systems replacements. Towards this aim, lignocellulosic biomass suggested as a possible sustainable source for the manufacturing of fuels and produced chemicals. The aims of this paper are to investigate different kinds of β-O-4 lignin model compounds for the production of value-added chemicals in presence of ionic liquids. Especially, a cheap β-O-4 lignin model Guaiacol glycerol ether (GGE) (Guaifenesin) is introduced to produce valuable chemicals and novel products. Methods: Research related to chemical depolymerization of lignocellulosic biomass activity is reviewed, the notes from different methods such as thermal and microwave collected during at least 10 years. So, this collection provides a good source for academic research and it gives an efficient strategy for the manufacturing of novel value-added chemicals at an industrial scale. Results: This research presented that ionic liquid microwave-assisted is a power saving, cost efficient, fast reaction, and clean way with high selectively and purity for production of high value chemicals rather that conversional heating. Guaiacol and catechol are some of these valuable chemicals that is produced from β-O-4 lignin model compounds with high word demands that are capable to produce in industry scale. Conclusion: The β-O-4 lignin model compounds such as Guaiacol glycerol ether (GGE) (Guaifenesin) are good platform for developing food materials, perfumery, biorefinery, and pharmaceutical industry by ionic liquids-assisted lignin depolymerization method.

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Screening of novel ascomycetes for the production of laccase enzyme using different lignin model compounds

International Journal of Pharma and Bio Sciences ◽

10.22376/ijpbs.2016.7.4.b452-458 ◽

2016 ◽

Vol 7 (4) ◽

Author(s):

RAJESHRI PATEL J ◽

LAKSHMI BHASKARAN

Keyword(s):

Model Compounds ◽

Lignin Model Compounds ◽

Lignin Model ◽

Laccase Enzyme

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Study of hydrogenation of petroleum asphaltenes

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19810409 ◽

1981 ◽

Vol 46 (2) ◽

pp. 409-418 ◽

Cited By ~ 2

Author(s):

Gustav Šebor ◽

Salvador Reynoso ◽

Milan Hájek ◽

Otto Weisser ◽

Jiří Mostecký

Keyword(s):

Temperature Region ◽

Catalytic Hydrogenation ◽

Starting Material ◽

Type Analysis ◽

H Nmr ◽

Petroleum Asphaltenes

Isolated petroleum asphaltenes were subjected to model thermal and catalytic hydrogenation experiments in the temperature region 300-450° C. The course of hydrogenation of the asphaltenes studied is discussed based on 1H-NMR type analysis of the starting material and the hydrogenation products.

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Study on the precision of the activated charcoal solvent desorption procedure - Correlation of desorption efficiencies

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19811332 ◽

1981 ◽

Vol 46 (6) ◽

pp. 1332-1347 ◽

Cited By ~ 2

Author(s):

Martin Koval

Keyword(s):

Activated Charcoal ◽

Carbon Disulphide ◽

Internal Standard ◽

Standard Addition ◽

Published Data ◽

Single Factor ◽

Gas Chromatograph ◽

Model Compounds ◽

Single Factor Analysis ◽

Acceptable Agreement

The described method uses activated charcoal sampling tubes for air sampling. Adsorbed compounds are eluted by the static desorption procedure with 1 ml of carbon disulphide, 0.5 ml of the supernatant is filtered off and, after internal standard addition, analysed on a gas chromatograph. Using synthetic calibration mixtures of model organic compounds with air, cumulative sampling and desorption efficiencies for 24 substances were determined for concentration ranges and sample volumes according to current Czechoslovak hygienic standards. Experimental results were treated with the single factor analysis of variance and the precision of the described procedure was estimated for the studied model compounds on the basis of residual sums of squares. Calculated values of cumulative sampling and desorption efficiencies and their precisions were compared with available published data and an acceptable agreement was found. In addition to that, cumulative sampling and desorption efficiencies were also found to be significantly correlated to molar volumes and other related molecular properties for some types of compounds.

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Configuration on the C=N double bond of monosubstituted amidines and amidoximes

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19893245 ◽

1989 ◽

Vol 54 (12) ◽

pp. 3245-3252 ◽

Cited By ~ 13

Author(s):

Bernard Tinant ◽

Janine Dupont-Fenfau ◽

Jean-Paul Declercq ◽

Jaroslav Podlaha ◽

Otto Exner

Keyword(s):

Double Bond ◽

Nitrogen Atom ◽

Steric Effects ◽

Model Compounds ◽

X Ray ◽

Analogous Model

Configuration on the C=N double bond of amidines and amidoximes is controlled by steric effects on the second nitrogen atom but there is a difference in the case of N’-monosubstituted derivatives: amidines prefer E configuration (conformation around the C-N bond sp) and amidoximes Z configuration (conformation ap). This was confirmed by the X-ray structures of two analogous model compounds N,N’-dimethyl-4-nitrobenzamidine (monoclinic, P21c, a = 10.855(3), b = 11.043(3), c = 8.593(3) Å, β = 105.69(2)°, V = 991.8(5) Å3, Z = 4, Dx = 1.29 g cm-3, CuKα, λ = 1.5418 Å, μ = 7.91 cm-1, F(000) = 408, T = 291 K, R = 0.065 for 1 265 observed reflections) and N’-methyl-4-nitrobenzamidoxime (monoclinic, P21/a, a = 6.699(2), b = 24.178(9), c = 6.075(2) Å, β = 106.20(3)°, V = 944.9(6) Å3, Z = 4, Dx = 1.37 g cm-3, CuKα, λ = 1.5418 Å, μ =9.22 cm-1, F(000) = 408, T = 291 K, R = 0.079 for 1 278 observed reflections).

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