O-containing Compounds Research Articles

The hydrodeoxygenation, hydrogenation, hydrodealkylation and ring-opening reaction in the hydrotreating of low temperature coal tar over Ni–Mo/γ-Al2O3 catalyst

The hydrotreatment of low temperature coal tar was carried out in a fixed bed reactor with the Ni–Mo/γ-Al2O3 catalyst. The compounds in the product and feedstock were determined by GC–MS and the effect of temperature, pressure and liquid hourly space velocity (LHSV) were studied based on this analysis. The results show that high temperature had adverse effect on the hydrogenation of aromatics but favorable effect on the ring-opening reaction and hydrodealkylation of aromatics. High pressure and low LHSV was very positive for all these three kinds of reaction of aromatics in coal tar. Most of the aromatics in the products of gasoline originate from the conversion of the monocyclic O-containing compounds. The reactivity of coal tar hydrocracking with the Ni–Mo/γ-Al2O3 catalyst is not very high because γ-Al2O3 is weak acid carrier. The ring-opening seldom occurs at temperatures lower than 380°C. Hydrodeoxygenation is the most important reaction to the upgrading of the coal tar. The gasoline fraction in the product mainly comes from the phenol hydrodeoxygenation in the coal tar hydrogenation process.

Solar STEP coal conversion: Fully solar-driven thermo- and electrochemical process for efficient transformation of coal to light fuel plus hydrogen

In this paper, the Solar Thermal Electrochemical Process (STEP) for coal conversion has been successfully introduced and developed for theoretical and experimental demonstration of efficient coal conversion to light fuel with perfectly coupling the solar thermo- and electrochemistry to lift the efficiency of solar utilization and lower endothermic reaction electrolysis potential. By adjusting two chemical processes powered by the solar thermal and electrical fields, the coal was efficiently and selectively converted to light fuel synergistically plus the hydrogen with the sole input of the solar energy and low emission of CO2. Just because the electricity is integrated into the thermolysis, it has found one way to combine the electrochemistry to the existing coal thermolysis technology so they work more efficiently with the easy selectivity of hydrocarbon fuel and O-containing compounds. The process, characterized with interaction of balancing and controlling the thermal and electrochemical components, provides lower potential and higher efficiency compared with the conventional coal thermolysis. The results show that the yields of the coal gasification and liquefaction were greatly improved with the coupling of thermolysis and electrolysis by reaching 38.5% and 48.8% at 360°C. The analytical data reveal that the products consist of abundant hydrogen, dominant hydrocarbons and rare O-containing compounds. The yield and selectivity were easily controlled by tuning the temperature and electrolysis current. Based on the results of the experimental analysis, the pathway and mechanism are proposed and explained for the STEP coal conversion process. Due to the combination of the solar thermo- and electrochemical process, this mechanism is shifted from the one reaction of the conventional thermolysis to the dual reaction involving electro-assisted thermolysis and thermo-assisted electrolysis. This study has important implications for the demonstrations of a novel approach of the efficient and energy-saving conversion of coal to light fuel driven by solar energy. The process has realized a transformation of low grade energy to high grade one by the proper utilization of solar energy and rational distribution of the heat and electricity to specific chemical reactions.

Some factors influencing the fluidity of coal blends: Particle size, blend ratio and inherent oxygen species

The fluidity performance of blended coals prepared from caking coal and non- or slightly-caking coal of different particle sizes, and the evolution of gaseous oxygen containing compounds (CO, CO2 and H2O) during carbonization are examined using the Gieseler plastometer method, and a flow-type fixed-bed quartz made reactor, respectively. The heating rate and temperature are 3°C/min and 1000°C, respectively. The Gieseler fluidity decreases with increasing blend ratio of non- or slightly-caking coal to caking coal. In addition, the fluidity tends to decrease with the decreasing particle size of non- or slightly-caking coal in blended coals. The evolution of CO, CO2 and H2O during the carbonization of single coals begins at 200–400°C, and the main peak of the formation rate appears at 450–700°C. The amount of gaseous O-containing compounds evolved until 1000°C from the non- or slightly-caking coals is greater than that of evolved from the caking coal. Additionally, a negative correlation is observed between the amounts of CO, CO2, and H2O that evolve up to the initial softening temperature and the maximum fluidity value. The profiles of formation rates of the three gaseous O-containing compounds from the blended coal during carbonization are different with additive average based on the results of single coals. Furthermore, for the blended coal, the starting temperature H2O evolution measured shifts to higher temperature in comparison with that of calculated based on the results of single coals. Therefore, it is possible that the H2O produced from non- or slightly-caking coal in blended coal or that the H2O formation reactions in blended coal during carbonization affects the fluidity performance of the blended coal.

Bio-Crude Production via Hydrothermal Liquefaction of Enteromorpha prolifera: Operating Condition Optimization and High-Resolution FT-ICR Mass Spectral Analysis

Abstract. is one of the main species causing green tide. In this study, hydrothermal liquefaction of E. was carried out, and the operating conditions were optimized using response surface methodology. The results indicated that hydrothermal liquefaction at 295°C with 14% solids content produced the highest bio-oil yield of 18.4%. The higher heating value was 31.9 to 34.2 MJ kg-1 and almost monotonically increased with increasing reaction temperature. The energy recovery, carbon recovery, and nitrogen recovery of bio-crude were mainly dependent on yield rather than elemental composition as the investigated variables changed. The chemical composition of bio-crude was characterized by Fourier transform ion cyclotron resonance mass spectrometry. The acidic O-containing compounds were mainly O2 class compounds, namely hexadecanoic acid and octadecanoic acid. The basic N-containing compounds were mainly nitrogenous heterocyclic compounds with carbon numbers of 20 to 40 and high degrees of unsaturation. Keywords: Bio-crude, FT-ICR MS, Hydrothermal liquefaction, Response surface methodology.

Generating Maillard reaction products in a model system of d-glucose and l-serine by continuous high-intensity ultrasonic processing

Abstract In this paper, a continuous ultrasonic processing system was established and firstly applied to a Maillard reaction (MR) model system of d -glucose and l -serine. Furthermore, the effects of high-intensity ultrasound assisted MR were compared with those of thermally induced MR through kinetic modelling. The ultrasonic MR had higher depletion rates of reactants as well as higher generation rates of intermediate and final MR products (MRPs) at relatively low processing temperatures (55 and 60 °C). However, both rates were lower for ultrasonic MR than thermal MR when the temperature was raised to 70 and 75 °C. Moreover, the ultrasonic MR had significantly lower activation energy compared with thermal MR. Lastly, three pyrazines, two amines and five O-containing flavour compounds were only produced in ultrasonic MR, not in thermal MR. The difference in flavour generation was attributed to the extremely high, albeit momentary, temperature and pressure condition produced by high-intensity ultrasound. Industrial relevance Ultrasound-assisted processing, a novel technology for non-thermal processing, has been utilized as an alternative to conventional thermal processing. High, albeit momentary, temperature and pressure that are generated by high-intensity ultrasound during processing provide a favourable environment for a number of chemical reactions. Moreover, strong shear stress, turbulence and agitation are among the unique characteristics generated by high-intensity ultrasound, which help to keep excellent mixing during food processing. In our study, a continuous ultrasonic processing system was established so as to achieve a good temperature control as well as to minimize the loss of volatile products during processing, which are major concerns to any liquid-based processing with ultrasound. Furthermore, a Maillard reaction (MR) model system of d -glucose and l -serine under the continuous ultrasonic processing were studied and compared to the most common batch processing of thermal MR through kinetic investigation at the same processing temperature and time conditions. The kinetic models that focused on reactants, intermediates, and final MR products (i.e. melanoidins and flavour compounds), and the kinetic parameters obtained for the MR system may enable controlling the reaction at industrial scale. The different flavour profile that was generated in ultrasonic MR points to new approaches to the food flavour industry to produce more alternatives and varieties.

ChemInform Abstract: Melamine Trisulfonic Acid (MTSA): An Efficient and Recyclable Heterogeneous Catalyst in Green Organic Synthesis

AbstractReview: 150 refs.

Perspectives on the crystal densities and packing coefficients of explosive compounds

We have investigated possible relationships between four crystal properties: experimental densities and computed intrinsic molecular volumes, packing coefficients and amounts of free space per molecule in the crystal lattices. Our focus was upon C-, H-, N-, O-containing explosive compounds. The objectives were to gain some insight into how densities might be increased, to improve detonation performance, and the amounts of free space per molecule decreased, to counter one of the factors promoting undesired sensitivity to accidental stimuli. The issue of molecular planarity was also examined. The best correlation found between the four properties is perhaps a surprising one: The free space per molecule increases as the molecules are bigger. On the other hand, some relationships that seem to be intuitively reasonable turn out to be quite weak. The principal positive conclusions are that it is desirable for explosive compounds to be composed of molecules that are small and preferably planar.

Petroleomics by Direct Analysis in Real Time-Mass Spectrometry.

The analysis of crude oil and its fractions by applying ambient ionization techniques remains underexplored in mass spectrometry (MS). Direct analysis in real time (DART) in the positive-ion mode was coupled to a linear quadrupole ion trap Orbitrap mass spectrometer (LTQ Orbitrap) to analyze crude oil, paraffin samples, and porphyrin standard compounds. The ionization parameters of DART-MS were optimized for crude oil analysis. DART-MS rendered the optimum conditions of the operation using paper as the substrate, T = 400°C, helium as the carrier gas, and a sample concentration ≥6 mg mL(-1). In the crude oils analysis, the DART(+)-Orbitrap mass spectra detected the typical N, NO, and O-containing compounds. In the paraffin samples, oxidized hydrocarbon species (Ox classes, where x = 1-4) with double-bond equivalent of 1-4 were detected, and their structures and connectivity were confirmed by collision-induced dissociation (CID) experiments. DART(+)-MS has identified the porphyrin standard compounds as [M + H](+) ions of m/z 615.2502 and 680.1763, where M = C44H30N4 and C44H28N4OV, respectively, based on the formula assignment and by phenyl losses observed on CID experiments.

Petroleum Biodegradation Effects on Polar Acidic Compounds and Correlation with Their Corresponded Hydrocarbon Fractions

A set of five oil samples from the same source rock, classified at different levels of biodegradation, was evaluated by high-resolution mass spectrometry (Orbitrap). O-containing acidic compounds from the acidic oil fractions were characterized by determining their molecular formulas. The effects of biodegradation were detected in all O classes and were consistent with the biodegradation of neutral compounds. Additionally, we found a slightly biodegraded sample that contained acidic compounds, biomarkers of a highly biodegraded sample. These results led us to propose a scale of biodegradation using acidic compounds, particularly those containing two oxygen atoms (carboxylic acids).

Focus on Fuel Quality: Removal of Sulfur-, Nitrogen-, and Oxygen-Containing Aromatic Compounds by Extraction from Hydrocarbons into the Regenerable Ionic Liquid

Extraction of S-, N-, and O-containing aromatic compounds from hydrocarbons modeling fuels was studied using an ionic liquid {1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([BMIM][NTf2])} doped with metal complexes (Ag, Cu, Co, and V). The silver additives were shown to be most efficient. Water was found to be an inert agent that did not deteriorate the efficiency of the extraction. This approach was considered as a method of removal of sulfur and nitrogen compounds present in oil products (gasoline and diesel fuels).

Product ion distributions for the reactions of NO+ with some N-containing and O-containing heterocyclic compounds obtained using SRI-TOF-MS

Product ion distributions for the reactions of NO+ with nine O-containing and six N-containing heterocyclic compounds present in human volatilome have been determined under the conditions of a Selective Reagent Ionization Time of Flight Mass Spectrometer (SRI-TOF-MS) at E/N values in the drift tube reactor ranging from 90 to 130Td. This study was undertaken to provide the kinetics data by which these heterocyclic compounds could be analyzed in biogenic media using SRI-TOF-MS. The specific heterocyclic compounds are furan, 2-methylfuran, 3-methylfuran, 2,5-dimethylfuran, 2-pentylfuran, 2,3-dihydrofuran, 1,3-dioxolane, 2-methyl-1,3-dioxolane, γ-butyrolactone, pyrrole, 1-methylpyrrole, pyridine, 2,6-dimethylpyridine, pyrimidine, and 4-methylpyrimidine. Charge transfer was the dominant mechanism in the majority of these NO+ reactions generating the respective M+ parent cation, but in the pyridine, pyrimidine, and 4-methylpyrimidine reactions, stable NO+M adduct ions were the major products with M+ ions as minor products. The reactions of dioxolanes with NO+ proceeded by hydride ion transfer only producing (M−H)+ ions. Fragmentation of the excited nascent product ions (M+)* did not occur for the majority of these reactions under the particular chosen conditions of the SRI-TOF-MS reactor, but partial fragmentation did occur in the 2,3-dihydrofuran and 2-pentylfuran reactions. However, lowering of the E/N in the drift tube suppresses fragmentation of (M+)* ions and promotes the formation of NO+M adduct ions, whereas increasing E/N has the opposite effect, as expected. The product ion distributions were seen to be independent of the humidity of the sample gas.

Quantification of trace O-containing compounds in GTL process samples via Fischer–Tropsch reaction by comprehensive two-dimensional gas chromatography/mass spectrometry

Comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC×GC–TOFMS) was successfully applied to eight real Brazilian Fischer–Tropsch (FT) product samples for the quantitative analysis of O-containing compounds. It not only allowed identifying and quantifying simultaneously a large number of O-containing compounds but also resolved many co-eluting components, such as carboxylic acids, which co-elute in one-dimensional gas chromatography. The homologous series of alcohols and carboxylic acids as trimethylsilyl derivatives were detected and identified at trace levels. The absolute quantification of each compound was accomplished with reliability using analytical curves. Linear alcohols (from C5 to C19), branched alcohols (C6–C13) and carboxylic acids (C4 to C12) were obtained in the range of 1.58mgg−1 to 14.75mgg−1, 0.51mgg−1 to 1.12mgg−1 and 0.21mgg−1 to 1.63mgg−1 of FT product samples, respectively. GC×GC–TOFMS provided a linear range (from 0.3ngµL−1 to 10ngµL−1), good precision (<8%), and excellent accuracy (recovery range of 77% to 118%) for quantification of individual O-containing compounds in FT product samples. The results can benefit the development of gas-to-liquid technologies from natural gas and guide the choice of an FT conversion process that generates clean products with higher added value.

Mn-Catalyzed Highly Efficient Aerobic Oxidative Hydroxyazidation of Olefins: A Direct Approach to β-Azido Alcohols.

An efficient Mn-catalyzed aerobic oxidative hydroxyazidation of olefins for synthesis of β-azido alcohols has been developed. The aerobic oxidative generation of azido radical employing air as the terminal oxidant is disclosed as the key process for this transformation. The reaction is appreciated by its broad substrate scope, inexpensive Mn-catalyst, high efficiency, easy operation under air, and mild conditions at room temperature. This chemistry provides a novel approach to high value-added β-azido alcohols, which are useful precursors of aziridines, β-amino alcohols, and other important N- and O-containing heterocyclic compounds. This chemistry also provides an unexpected approach to azido substituted cyclic peroxy alcohol esters. A DFT calculation indicates that Mn catalyst plays key dual roles as an efficient catalyst for the generation of azido radical and a stabilizer for peroxyl radical intermediate. Further calculation reasonably explains the proposed mechanism for the control of C-C bond cleavage or for the formation of β-azido alcohols.

Catalytic hydrothermal upgrading of crude bio-oils produced from different thermo-chemical conversion routes of microalgae

This study presents experimental results that compare the use of hydrothermal liquefaction (HTL), alcoholysis (Al), pyrolysis (Py) and hydropyrolysis (HPy) for the production of bio-oil from a microalga (Chlorella pyrenoidosa) and the catalytic hydrothermal upgrading of crude bio-oils produced by these four conversion routes. The yields and compositions of bio-oil, solid residue, and gases were evaluated and compared. HTL resulted in a bio-oil that has a higher energy density and superior fuel properties, such as thermal and storage stabilities, compared with the other three conversion routes. The N in crude bio-oils produced from Py and HPy is more easily removed than that in the bio-oils produced from HTL and Al. The upgraded bio-oils contain reduced amounts of certain O-containing and N-containing compounds and significantly increased saturated hydrocarbon contents. All of the upgraded bio-oils have a larger fraction boiling below 350°C than their corresponding crude bio-oils.

Effect of steam concentration on char reactivity and structure in the presence/absence of oxygen using Shengli brown coal

Steam-char reactions play a vital role in the gasification process and the presence of oxygen is inevitable in almost all commercial gasifiers. This study aims to investigate the effects of steam concentration on the behavior of Chinese Shengli brown coal gasification in the presence and absence of low concentration of oxygen in a newly-designed drop-tube quartz reactor. Experimental results indicate that the variation in steam concentration had a significant impact on coal conversion, largely depending on reaction temperatures and availability of oxygen. The coal conversion could somehow decrease with increasing steam concentration in the presence of low concentration of oxygen. Meanwhile, the presence of oxygen in the gas has enhanced the Na retention in char probably due to the formation of O-containing compounds or complexes on the char surface. The char structure measured by Raman spectroscopy suggests that the selective consumption of small aromatic ring systems by steam-char reactions was getting less significant when the steam concentration increased to more than 15% by volume. Furthermore, the isothermal reactivities of chars determined by TGA in air imply that the reaction pathways of char-steam and char-oxygen were likely different as the reactivity curves showed totally different shapes.

Cyclodepsipeptides and other O-containing heterocyclic metabolites from Beauveria felina EN-135, a marine-derived entomopathogenic fungus.

Bioassay-guided fractionation of a culture extract of Beauveria felina EN-135, an entomopathogenic fungus isolated from a marine bryozoan, led to the isolation of a new cyclodepsipeptide, iso-isariin D (1); two new O-containing heterocyclic compounds that we have named felinones A and B (2 and 3); and four known cyclodepsipeptides (4–7). The structures were elucidated via spectroscopic analysis, and the absolute configurations of 1 and 2 were determined using single-crystal X-ray diffraction and CD, respectively. All isolated compounds were evaluated for antimicrobial activity and brine-shrimp (Artemia salina) lethality.

Membrane Science for Liquid Organic Fuel Cells

This study was aimed at understanding the interaction of liquid organic fuels with Nafion® membranes. Carbocyclic compounds, O-containing and N-containing heterocyclic compounds were investigated as fuels. We report the properties of PEMs, such as solvent uptake, proton conductivity and fuel cell performance in the presence of such liquid organic fuels.

Accurate prediction of the enthalpies of formation for xanthophylls

This study investigates the applications of computational approaches in the prediction of enthalpies of formation (ΔH(f)) for C-, H-, and O-containing compounds. Molecular mechanics (MM4) molecular mechanics method, density functional theory (DFT) combined with the atomic equivalent (AE) and group equivalent (GE) schemes, and DFT-based correlation corrected atomization (CCAZ) were used. We emphasized on the application to xanthophylls, C-, H-, and O-containing carotenoids which consist of ∼ 100 atoms and extended π-delocaization systems. Within the training set, MM4 predictions are more accurate than those obtained using AE and GE; however a systematic underestimation was observed in the extended systems. ΔH(f) for the training set molecules predicted by CCAZ combined with DFT are in very good agreement with the G3 results. The average absolute deviations (AADs) of CCAZ combined with B3LYP and MPWB1K are 0.38 and 0.53 kcal/mol compared with the G3 data, and are 0.74 and 0.69 kcal/mol compared with the available experimental data, respectively. Consistency of the CCAZ approach for the selected xanthophylls is revealed by the AAD of 2.68 kcal/mol between B3LYP-CCAZ and MPWB1K-CCAZ.

Reactions of Verbenol Epoxide with Aromatic Aldehydes Containing Hydroxy or Methoxy Groups in the Presence of Montmorillonite Clay

AbstractThe reactions of (−)‐cis‐verbenol epoxide with a number of aromatic aldehydes containing OH and/or MeO groups in the presence of montmorillonite K10 clay have been studied. Several new O‐containing heterocyclic compounds with different frameworks, including compounds with a previously unknown octahydro‐2H‐4,6‐(epoxymethano)chromene framework, have been synthesized. Introduction of one donor substituent in the benzaldehyde molecule led to a decrease in the total yield of intermolecular by formed products, while the introduction of two and more substituents led to an increase in the yield of these products.

Catalytic treatment of crude algal bio-oil in supercritical water: optimization studies

We have investigated the catalytic treatment of a crude algal liquefaction bio-oil in supercritical water to discover how the properties of the treated oil depend on the experimental conditions. An L9 (34) orthogonal array design (OAD) with four factors at three levels was employed. The four factors were temperature (varied from 430–530 °C), time (varied from 2–6 h), catalyst type (Pt/C, Mo2C, HZSM-5), and catalyst loading (varied from 5–20 wt%). We used a direct analysis to determine the relationship between experimental conditions and properties of treated oils. The oil properties we examined were elemental composition, atomic ratios, chemical composition, and higher heating value. Of the four factors, the 100 °C variation in temperature was always the most influential for each of the oil properties examined. Of the remaining three factors, catalyst type had the greatest influence on the fatty acid content of the treated oil and the fraction of N- and O-containing compounds in the oil. Catalyst loading had the greatest effect on the higher heating value and O/C ratio in the treated oil. Reaction time had the greatest effect on the H/C and N/C ratios. The results demonstrated that treatment in supercritical water at 430 °C led to roughly a halving of the N and O content of the oil, a reduction in S to below detection limits, and about a 10% improvement in the higher heating value of the bio-oil. Within the parameter space investigated, the conditions leading to the highest content of saturated compounds in the treated oil are 430 °C, 6 h, with a 10 wt% loading of Mo2C as the catalyst. Around 76 wt% of the carbon in the feedstock was retained in the treated oil at these conditions.