scholarly journals EVALUATION OF THE CHEMICAL COMPOSITION AND STRUCTURE OF ASPHALTENES FROM THREE OFFSHORE BRAZILIAN BIODEGRADED HEAVY OILS

Química Nova ◽  
2020 ◽  
Author(s):  
Hemmely Severino ◽  
Christiane Pinto ◽  
André Spigolon ◽  
Carlos Mello ◽  
Tais Silva ◽  
...  
Keyword(s):  
Quantitative Data ◽  
Structural Data ◽  
Proton Nuclear Magnetic Resonance ◽  
Aliphatic Chain ◽  
Heavy Oils ◽  
H Nmr ◽  
Polar Groups ◽  
Composition And Structure ◽  
Two Samples ◽  
High Degree

Asphaltenes fractions were extracted and purified from three heavy Brazilian oils. Their mass compositions of C, H, N, Ni and V were obtained from elemental analysis and S and O atomic percentages from EDS. The H/C ratios showed high degree of unsaturation, while the O atomic percentages indicated more pronounced biodegradation effects on two samples. Quantitative data on N, Ni, and V and semi-quantitative data on S were related to oils origins. The structural data of asphaltenes were explored by combining Fourier transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance (1 H NMR). The oil with the lower degree of biodegradation contained asphaltenes with a lower level of condensed aromatic rings and longer aliphatic chain substituents. The asphaltenes obtained from the two most biodegraded oils showed similarities of polar groups and the presence of carboxylic functions, as well as lower contents of aliphatic substituents. The quality and quantity of occluded hydrocarbons were assessed after the mild oxidation of the separated asphaltenes fractions. It was suggested that the severe biodegradation which altered these structures may also be responsible to affect their occluded hydrocarbons.

Microscopic versus process parameters in heavy-oil upgrading

1992 ◽  
Vol 50 (1) ◽  
pp. 366-367
Author(s):  
V.A. Munoz ◽  
R.J. Mikula ◽  
C. Payette ◽  
W.W. Lam
Keyword(s):  
Molecular Weight ◽  
Liquid Fuels ◽  
Chemical Components ◽  
Heavy Oils ◽  
Synthetic Fuels ◽  
High Hydrogen ◽  
Optical Texture ◽  
Polar Groups ◽  
Anisotropic Character ◽  
Planar Molecules

The transformation of high molecular weight components present in heavy oils into useable liquid fuels requires their decomposition by means of a variety of processes. The low molecular weight species produced recombine under controlled conditions to generate synthetic fuels. However, an important fraction undergo further recombination into higher molecular weight components, leading to the formation of coke. The optical texture of the coke can be related to its originating components. Those with high sulfur and oxygen content tend to produce cokes with small optical texture or fine mosaic, whereas compounds with relatively high hydrogen content are likely to produce large optical texture or domains. In addition, the structure of the parent chemical components, planar or nonplanar, determines the isotropic or anisotropic character of the coke. Planar molecules have a tendency to align in an approximately parallel arrangement to initiate the formation of the nematic mesophase leading to the formation of anisotropic coke. Nonplanar highly alkylated compounds and/or those rich in polar groups form isotropic coke. The aliphatic branches produce steric hindrance to alignment, whereas the polar groups participate in cross-linking reactions.

Synthesis and properties of a benzoxazine monomer containing maleimide and biphenyl groups

2021 ◽  
pp. 095400832199674
Author(s):  
Tao Guo ◽  
Yang Fan ◽  
Chang Bo ◽  
Zhang Qi ◽  
Han Tao ◽  
...  
Keyword(s):  
Weight Loss ◽  
Loss Rate ◽  
Proton Nuclear Magnetic Resonance ◽  
Significant Weight Loss ◽  
Scanning Calorimetry ◽  
Weight Loss Rate ◽  
Reaction Heat ◽  
H Nmr ◽  
Curing Reaction ◽  
Dsc Curves

Benzoxazine resin exhibits excellent properties and is widely used in many fields. Herein, the synthesis of a novel compound, the bis(2,4-dihydro-2 H-3-(4- N-maleimido)phenyl-1,3-benzoxazinyl)biphenyl (BMIPBB), has been reported, which was synthesized by reacting N-(4-aminophenyl)maleimide (APMI), formaldehyde, and 4,4’-dihydroxybiphenyl. 1,3,5-three(4-(maleimido)phenyl)-1,3,5-triazine (TMIPT) was formed as an intermediate during the reaction. The proton nuclear magnetic resonance (1H-NMR) and Fourier transform-infrared (FTIR) spectroscopy experiments were conducted to determine the structure of BMIPBB. BMIPBB was obtained as a reddish-brown solid in 40.1% yield. The thermal properties of BMIPBB were investigated using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) techniques. Analysis of the DSC curves revealed that the broad peak representing the release of curing reaction heat appeared in the temperature range of 140–330°C. The peak temperature was 242.59°C and the heat of the reaction was 393.82 J/g, indicating that the rate of the curing reaction was low and the heat of the reaction was high. Analysis of the TGA results revealed that the weight loss rate was 5% at 110°C. The monomer exhibited a significant weight loss in the range of 320–500°C. The compound lost 50% of its weight at a temperature of 427°C.

scholarly journals Putative imbalanced amino acid metabolism in rainbow trout long term fed a plant-based diet as revealed by 1H-NMR metabolomics

2021 ◽  
Vol 10 ◽  
Author(s):  
Catherine Deborde ◽  
Blandine Madji Hounoum ◽  
Annick Moing ◽  
Mickaël Maucourt ◽  
Daniel Jacob ◽  
...  
Keyword(s):  
Amino Acids ◽  
Rainbow Trout ◽  
Amino Acid ◽  
Amino Acid Content ◽  
Proton Nuclear Magnetic Resonance ◽  
Free Form ◽  
Metabolomic Analysis ◽  
Nmr Metabolomics ◽  
H Nmr

Abstract The long-term effect of a plant (P)-based diet was assessed by proton nuclear magnetic resonance (1H-NMR) metabolomics in rainbow trout fed a marine fish meal (FM)–fish oil (FO) diet (M), a P-based diet and a control commercial-like diet (C) starting with the first feeding. Growth performances were not heavily altered by long-term feeding on the P-based diet. An 1H-NMR metabolomic analysis of the feed revealed significantly different soluble chemical compound profiles between the diets. A set of soluble chemical compounds was found to be specific either to the P-based diet or to the M diet. Pterin, a biomarker of plant feedstuffs, was identified both in the P-based diet and in the plasma of fish fed the P-based diet. 1H-NMR metabolomic analysis on fish plasma and liver and muscle tissues at 6 and 48 h post feeding revealed significantly different profiles between the P-based diet and the M diet, while the C diet showed intermediate results. A higher amino acid content was found in the plasma of fish fed the P-based diet compared with the M diet after 48 h, suggesting either a delayed delivery of the amino acids or a lower amino acid utilisation in the P-based diet. This was associated with an accumulation of essential amino acids and the depletion of glutamine in the muscle, together with an accumulation of choline in the liver. Combined with an anticipated absorption of methionine and lysine supplemented in free form, the present results suggest an imbalanced essential amino acid supply for protein metabolism in the muscle and for specific functions of the liver.

scholarly journals Time–frequency analysis of serum with proton nuclear magnetic resonance for diagnosis of pancreatic cancer

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Asahi Sato ◽  
Toshihiko Masui ◽  
Akitada Yogo ◽  
Takashi Ito ◽  
Keiko Hirakawa ◽  
...  
Keyword(s):  
Pancreatic Cancer ◽  
Carbohydrate Antigen ◽  
Serum Markers ◽  
Proton Nuclear Magnetic Resonance ◽  
Serum Samples ◽  
Time Frequency ◽  
H Nmr ◽  
Free Induction ◽  
Short Time ◽  
Long Term Survivors

AbstractAlthough serum markers such as carcinoembryonic antigen (CEA) and carbohydrate antigen (CA19-9) have been widely used in screening for pancreatic cancer (PC), their sensitivity and specificity are unsatisfactory. Recently, a novel tool of analyzing serum using the short-time Fourier transform (STFT) of free induction decays (FIDs) obtained by 1H-NMR has been introduced. We for the first time evaluated the utility of this technology as a diagnostic tool for PC. Serum was obtained from PC patients before starting any treatments. Samples taken from individuals with benign diseases or donors for liver transplantation were obtained as controls. Serum samples from both groups underwent 1H-NMR and STFT of FIDs. STFT data were analyzed by partial least squares discriminant analysis (PLS-DA) to clarify whether differences were apparent between groups. As a result, PLS-DA score plots indicated that STFT of FIDs enabled effective classification of groups with and without PC. Additionally, in a subgroup of PC, long-term survivors (≥ 2 years) could be discriminated from short-term survivors (< 2 years), regardless of pathologic stage or CEA or CA19-9 levels. In conclusion, STFT of FIDs obtained from 1H-NMR have a potential to be a diagnostic and prognostic tool of PC.

scholarly journals Nitrone Modified Gold Nanoparticles: Synthesis, Characterization and Their Potential as 18F-Labeled PET Probes via I-SPANC

2019 ◽  
Author(s):  
Sara Ghiassian ◽  
Lihai Yu ◽  
Pierangelo Gobbo ◽  
Ali nazemi ◽  
Tommaso Romagnoli ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Nmr Spectroscopy ◽  
Gold Nanoparticle ◽  
Molecular Level ◽  
Prosthetic Group ◽  
H Nmr ◽  
Nanoparticles Synthesis ◽  
Interfacial Strain ◽  
Pet Probes ◽  
High Degree

A bioorthogonal gold nanoparticle template displaying interfacial nitrone functional groups for bioorthogonal interfacial strain-promoted alkyne-nitrone cycloaddition (I-SPANC) reactions has been synthesized. The Nitrone-AuNPs were characterized in detail using <sup>1</sup>H NMR spectroscopy, TEM, TGA, and XPS and a nanoparticle raw formula was calculated. The ability to control the conjugation of molecules of interest at the molecular level onto the Nitrone-AuNPs template allowed us to create a methodology for the synthesis of AuNP-based radiolabeled probes with a high degree of loading using copper free, strained-promoted cycloaddition. To this end, we also describe the synthesis of a new prosthetic group containing a strained-alkyne capable of clicking hot <sup>18</sup>F-label onto complementary azide or nitrone labelled agents.

Biophysical properties of electrospun chitosan-grafted poly(lactic acid) nanofibrous scaffolds loaded with chondroitin sulfate and silver nanoparticles

2021 ◽  
pp. 088532822110464
Author(s):  
Alexandre F Júnior ◽  
Charlene A Ribeiro ◽  
Maria E Leyva ◽  
Paulo S Marques ◽  
Carlos R J Soares ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Lactic Acid ◽  
Proton Nuclear Magnetic Resonance ◽  
Poly Lactic Acid ◽  
Fibroblast Cells ◽  
Biophysical Properties ◽  
Electrospinning Technique ◽  
Average Pore ◽  
H Nmr ◽  
Substitution Degree

The aim of this work was to study the biophysical properties of the chitosan-grafted poly(lactic acid) (CH-g-PLA) nanofibers loaded with silver nanoparticles (AgNPs) and chondroitin-4-sulfate (C4S). The electrospun CH-g-PLA:AgNP:C4S nanofibers were manufactured using the electrospinning technique. The microstructure of the CH-g-PLA:AgNP:C4S nanofibers was investigated by proton nuclear magnetic resonance (1H-NMR), scanning electron microscopy (SEM), UV-Visible spectroscopy (UV-Vis), X-ray diffraction (XRD), and Fourier transform infrared (ATR-FTIR) spectroscopy. ATR-FTIR and 1H-NMR confirm the CH grafting successfully by PLA with a substitution degree of 33.4%. The SEM measurement results indicated apparently smooth nanofibers having a diameter range of 340 ± 18 nm with porosity of 89 ± 3.08% and an average pore area of 0.27 μm2. UV-Vis and XRD suggest that silver nanoparticles with the size distribution of 30 nm were successfully incorporated into the electrospun nanofibers. The water contact angle of 12.8 ± 2.7° reveals the hydrophilic nature of the CH-g-PLA:AgNP:C4S nanofibers has been improved by C4S. The electrospun CH-g-PLA:AgNP:C4S nanofibers are found to release ions Ag+ at a concentration level capable of rendering an antimicrobial efficacy. Gram-positive bacteria ( S.aureus) were more sensitive to CH-g-PLA:AgNP:C4S than Gram-negative bacteria ( E. coli). The electrospun CH-g-PLA:AgNP:C4S nanofibers exhibited no cytotoxicity to the L-929 fibroblast cells, suggesting cytocompatibility. Fluorescence microscopy demonstrated that C4S promotes the adhesion and proliferation of fibroblast cells onto electrospun CH-g-PLA:AgNP:C4S nanofibers.

Experimental and Computational Insights into Bis-indolylmethane Derivatives as Potent Antimicrobial Agents Inhibiting 2,2-dialkylglycine Decarboxylase

2021 ◽  
Vol 17 ◽  
Author(s):  
Dnyaneshwar T. Nagre ◽  
Bapu R. Thorat ◽  
Suraj N. Mali ◽  
Mazhar Farooqui ◽  
Brijmohan Agrawal
Keyword(s):  
Antimicrobial Agents ◽  
In Silico Analysis ◽  
Proton Nuclear Magnetic Resonance ◽  
Gas Chromatography Mass Spectrometry ◽  
Amino Acid Residues ◽  
Standard Drug ◽  
H Nmr ◽  
Highly Active ◽  
Dialkylglycine Decarboxylase

Background: A series of bis(indolyl)methanes (3a-3o) have been synthesized using a greener and new approach using the reaction of different substituted aldehydes and indole in the presence of an easily available and biodegradable base such as piperidine in acetic acid at room temperature and characterized with UV (Ultraviolet-visible spectroscopy), Gas chromatography-mass spectrometry (GC-MS), Proton nuclear magnetic resonance (H-NMR), and Fourier transform infrared spectroscopy (FTIR). Methods: All 15 newly synthesized compounds (3a-3o) were subjected to in-vitro anti-microbial activity determination and compared with the known standard drug ciprofloxacin (1-2 µg/mL). Our in-silico analysis on the target protein, pdb id: 1d7u suggested that these analogues would be highly active against bacterial targets and thus, would act as good antimicrobial agents. Results: All 15 newly synthesized compounds (3a-3o) displayed potent activity on various experimental microbial strains (1.0-1.4 µg/mL). Compound, 3k was obtained as the best docked compound against common bacterial target enzyme, (pdb id:1d7u). The standard, Ciprofloxacin, retained the docking score of -111.3 Kcal/mol with similar binding amino acid residues (LYS272 (Pi-cation); ALA A:245 (Pi-sigma); TRP A:138 (Pi-Pi); ALA A:112; and MET A:141 (Pi-alkyl)) as of inbound. Conclusion : We believe that our current study would shed more light on the development of potent bis(indolyl)methanes as antimicrobial agents.

Partition of tert-dodecyl mercaptan in systems containing styrene, polystyrene, and polybutadiene. Its effect on the macromolecular characteristics of high-impact poly styrene

e-Polymers ◽  
2007 ◽  
Vol 7 (1) ◽  
Author(s):  
Natalia Casís ◽  
Carla Vanesa Luciani ◽  
Diana Alejandra Estenoz ◽  
Marisa Martinelli ◽  
Miriam Strumia ◽  
...  
Keyword(s):  
Total Concentration ◽  
Strong Dependence ◽  
Monomer Conversion ◽  
Theoretical Work ◽  
High Impact ◽  
Proton Nuclear Magnetic Resonance ◽  
Molecular Weights ◽  
H Nmr ◽  
Dodecyl Mercaptan ◽  
Good Agreement

AbstractThis work investigates the distribution between phases of tert-dodecyl mercaptan (t-DDM) in systems containing styrene (St), polystyrene (PS), and polybutadiene (PB) with the aim of studying its effect on the molecular macrostructure of High-Impact Polystyrene (HIPS) produced via the bulk process. Experimental work involved the study of several St/PS/PB/t-DDM blends, and of 2 polymerizations of St in presence of PB (with and without t-DDM). Blends were prepared with increasing PS/St ratios to emulate monomer conversions of 7, 9, 11, 13, and 15%, employing 2 base PSs of different molar masses, and several total concentrations of t-DDM. Measurements by Proton Nuclear Magnetic Resonance (1H NMR) indicate that t-DDM is almost evenly distributed between the phases at room temperature. In addition, for samples taken along the 2 investigated polymerizations, monomer conversion, grafting efficiency, and free PS molecular weights were measured. Theoretical work involved first to model the species partitions through the Flory-Huggins theory [1]; and then, to combine such partition model with a polymerization model extended from that by Casís et al. [2]. Theoretical estimations were in good agreement with experimental determinations. Simulations suggest that t-DDM partition coefficients exhibit a weak dependence with temperature, but a strong dependence with its total concentration. Also, the combined partition/polymerization model indicates that the free PS contained in the occlusion regions exhibits lower molecular weights than that in the continuous matrix.

Crosslinking Density of Silk Fibroin – Rice Starch Hydrogels Modified with Trisodium Trimetaphosphate

2013 ◽  
Vol 446-447 ◽  
pp. 366-372 ◽  
Author(s):  
Anucha Racksanti ◽  
Sorapong Janhom ◽  
Sittiporn Punyanitya ◽  
Ruangsri Watanesk ◽  
Surasak Watanesk
Keyword(s):  
Silk Fibroin ◽  
Nmr Spectra ◽  
Crosslinking Density ◽  
Proton Nuclear Magnetic Resonance ◽  
Rice Starch ◽  
Infrared Spectrometry ◽  
Solution Casting ◽  
H Nmr ◽  
Nmr Spectrometry ◽  
Mb Adsorption

Silk fibroin (SF) and rice starch (RS) are both biopolymers being non-toxic, biocompatible and biodegradable which can be utilized as hydrogels. The aim of this study was to prepare the SF–RS hydrogels modified with trisodium trimetaphosphate (STMP) and determine its crosslinking density for providing a guideline for preparing better quality absorbable hydrogels. The SF–RS hydrogels modified with various percentages of STMP were prepared by solution casting at pH 12 then neutralized to pH 7. The functional groups and molecular linkages of the hydrogels were investigated by Fourier transform infrared spectrometry (FTIR) and proton nuclear magnetic resonance (1H NMR) spectrometry, respectively. Finally, the crosslinking density of the hydrogels was determined by UV/Vis spectrophotometry via the measurement of the relative amount of methylene blue (RMB) bound to the hydrogels. Results from the FTIR and 1H NMR spectra revealed that linkages within the hydrogels occurred mainly between the O–H groups of RS and the triphosphate groups of STMP. From the MB adsorption study, the crosslinking density of the SF–RS hydrogel with 1.0 %w/w STMP at the 60 min saturation time was approximately 63 %.

Sign in / Sign up

Export Citation Format

Share Document