首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 46 毫秒
1.
《Fuel》2006,85(14-15):2071-2080
The diminishing clean oil reserve is driving the search for new or improved ways to reduce the level of NSO-containing species found in high abundance in heavy crude oils. Hydrotreatment is the currently preferred technique to remove those polar species. Unfortunately, nitrogen-containing compounds cause coke formation on the surface of the hydrotreatment catalyst, leading to partial or complete deactivation. Here, positive- and negative-ion electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS) identify those nitrogen compounds that resist hydrotreatment. ESI preferentially ionizes polar (e.g., heteroatom-containing) species: basic molecules are detected as positive ions and acidic/neutral molecules as negative ions. FT-ICR MS resolves thousands of species in a single mass spectrum, allowing for unambiguous determination of elemental composition, CcHhNnOoSs, for identification of compound “class” (numbers of N, O, S heteroatoms, “type” (rings plus double bonds), and carbon number (revealing the extent of alkylation). We find that hydrotreatment-resistant compounds typically contain a single nitrogen atom, both pyridinic benzalogs and pyrollic benzalogs. Compounds with more than one heteroatom, such as Ox, NxOy, NxSy and Nx, are partially removed. Compound classes with lower double bond equivalents or fewer CH2 groups are preferentially removed. Species that contain OxSy are fully removed by hydrotreatment.  相似文献   

2.
Atmospheric residue from Saudi Arabia light crude oil was subjected to the hydrotreating process in a continuous fixed-bed reactor with hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) catalysts. The detailed molecular composition of the polar heteroatom species in the feedstock and products was determined by electrospray ionization (ESI) Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) combined with other analytical methods. The ESI FT-ICR MS analysis indicates that the N1 class species have the highest relative abundance. In the hydrotreating process, small neutral N1 class species with high aromaticity and short side chains showed the highest relative abundance and were defined as easily removable compounds. High aromaticity and small molecule basic N1 compounds exhibited higher catalytic activity towards hydrogenation. The N1S1 class species were converted to the N1 class species, or even hydrocarbons, by the preferential removal of the sulfur atoms. Most of the N1O1 class species were difficult to remove, because of their stable chemical structure.  相似文献   

3.
微藻水热液化生物油化学性质与表征方法综述   总被引:2,自引:0,他引:2       下载免费PDF全文
张冀翔  蒋宝辉  王东  魏耀东 《化工学报》2016,67(5):1644-1653
微藻水热液化生物油由于性质较差,不能直接作为车载燃料使用,与现代石油炼制工艺结合是一种新的应用途径。综述了微藻生物油的化学性质,包括化学组成、官能团组成与杂原子化合物组成等信息,比较分析了GC-MS、FTIR、NMR和FT-ICR MS等表征方法的异同,简要回顾了微藻水热液化反应机理和精制方法。重点指出微藻水热液化生物油中含氧、含氮化合物含量较高,并具有较高的芳香度和不饱和度,催化加氢精制能够有效脱除杂原子,并增加烷烃含量。微藻基生物燃料的发展,不仅需要精制工艺的提升,也有赖于表征方法的进步。  相似文献   

4.
A new and promising nitrosyl ruthenium complex, [Ru(NO)(bdqi-COOH)(terpy)](PF6)3, bdqi-COOH is 3,4-diiminebenzoic acid and terpy is 2,2′-terpyridine, has been synthesized as a NO donor agent. The procedure used for [Ru(NO)(bdqi-COOH)(terpy)](PF6)3 synthesis has, apparently, yielded the formation of two isomers in which the ligand bdqi-COOH appears to be coordinated in its reduced form (bdcat-COOH), which could have differences in their pharmacological properties. Therefore, it was intended to separate the two possible isomers by high-performance liquid chromatography (HPLC) and to characterize them by high resolution mass spectrometry (QTOF MS) and by magnetic nuclear resonance spectroscopy (NMR). The results obtained by MS showed that the ESI-MS mass spectra of both HPLC column fractions, e.g. peak 1 and peak 2, are essentially equal, showing that both isomers display nearly identical gas-phase behavior with clusters of isotopologue ions centered at m/z 573, m/z 543 and m/z 513. Regarding the NMR analysis, the results showed that the positional isomerism is located in the bdqi-COOH ligand. From the observed results it can be concluded that the synthesis procedure that has been used results in the formation of two [Ru(terpy)(bdqi-COOH)NO](PF6)3 isomers.  相似文献   

5.
负离子电喷雾-傅里叶变化离子回旋共振质谱仪(Neg ESI FT-ICR MS)具有超高的分辨率,可用于分析重油中杂原子化合物的组成及分布.运用Neg ESI FT-ICR MS,研究委内瑞拉奥里常渣减黏裂化反应前后杂原子化合物,建立了分子组成的解析方法.结果表明,常渣中O_2类化合物的相对丰度最大,减黏产物中N_1类化合物的相对丰度最大.不同缩合度,质荷比小的O_2类化合物减黏裂化反应后显著增加.委内瑞拉常渣及其减黏产物中相对丰度最强的O_2类化合物均是双环环烷酸.减黏裂化反应使得O2类化合物发生了裂化反应,生成碳数更少、分子质量更小的化合物.  相似文献   

6.
The brown coal liquefaction (BCL) process is a two-stage liquefaction (hydrogenation) process developed for Victorian brown coal in Australia. The BCL process has a solvent de-ashing step to remove the ash and heavy preasphaltenes from the heavy liquefaction product (vacuum residue) derived from the coal in primary hydrogenation and named CLB (coal liquid bottom). This solvent de-ashing step uses toluene or coal-derived naphtha as a de-ashing solvent (DAS). After dissolving the CLB into the solvent (CLB/solvent ratio, 1/8–1/4, w/w) under high temperature (200–290°C) and high pressure (4–5 MPa), insoluble solid particles which consist of ash and heavy preasphaltenes are settled by gravity and separated from the solution as an ash-concentrated slurry. The ash-concentrated slurry and the de-ashed solution are withdrawn from the settler as an underflow and overflow, respectively. The de-ashed heavy product is recovered from the solution by eliminating the solvent and is further hydrogenated in secondary hydrogenation. The authors have reported on the solubility of CLB in toluene and the settling velocity (V) of the boundary of ash content in the settler under de-ashing conditions. This paper discusses the effects of de-ashing conditions on ash concentration in the settler bottom and the operating conditions of a continuous de-ashing system. The ash content in underflow (CUF, kg/kg or wt.%) at the settler bottom was found to increase with temperature and to decrease with the rate (flux) of downward flow (underflow). The maximum CUF, Z, is expressed by the equation: Z=BCLB(FL/0.35)−0.32(T/523)4.26, where BCLB, FL and T are the characteristic parameters of organic CLB (kg/kg or wt.%), flux of underflow in the settler (kg/m2 s) and temperature (K), respectively. BCLB is also expressed by using the analytical results of organic insolubles in the CLB under de-ashing conditions. Finally, stable operating conditions of a continuous de-ashing system are confirmed to be determined as the following qualifications: |Vu|<|V|, WUF>WSA/CUF and Z>CUF, where |Vu|, |V|, WSA and WUF are the upward velocity of the solution in the settler (mm/s), settling velocity of the ash boundary (mm/s) in the settler, flow rate of ash in the feed slurry (kg/h) and flow rate of underflow (kg/h), respectively. Under these qualified conditions, the 50 t/d pilot plant constructed in Australia was operated under stable conditions for 3700 h using toluene as a DAS.  相似文献   

7.
The aim of this study was to evaluate the possibility of using polyols derived from liquefied cork in the production of novel bio‐based polyurethane foams (PUFs). For that purpose, different liquefaction conditions were used at atmospheric pressure and moderate temperature where poly(ethylene glycol) and glycerol were used as solvents and sulfuric acid as catalyst. The ensuing polyols were used to produce foams which were characterized using structural, morphological, thermal and mechanical analyses to demonstrate that liquefaction conditions play a crucial role in the properties of the foams. The resulting foams exhibited the typical cellular structure of PUFs with low densities (57.4–70.7 kg m?3) and low thermal conductivities (0.038–0.040 W m?1 K?1). However, the mechanical properties differed significantly depending on the liquefaction conditions. The best stress–strain results were obtained for PUFs prepared using the polyol with lowest IOH and water content (Young's modulus of 475.0 kPa, compressive stress (σ10%) of 34.6 kPa and toughness of 7397.1 J m?3). This PUF was thermally stable up to 200 °C and presented a glass transition temperature of around 27 °C. The results obtained demonstrate that these polyols from liquefied cork yield PUFs that are adequate materials for insulation applications. © 2014 Society of Chemical Industry  相似文献   

8.
High-resolution mass spectrometry equipped with electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) sources was used to enhance the characterization of phytochemicals of ethanol extracts of Manilkara zapota L. leaves (ZLE). Sugar compounds, dicarboxylic acids, compounds of phenolic acids and flavonoids groups, and other phytochemicals were detected from the leaves. Antioxidant activity and inhibition potentiality of ZLE against α-glucosidase enzyme, and elastase enzyme activities were evaluated in in vitro analysis. ZLE significantly inhibited activities of α-glucosidase enzyme at a lower concentration (IC50 2.51 ± 0.15 µg/mL). Glucose uptake in C2C12 cells was significantly enhanced by 42.13 ± 0.15% following the treatment with ZLE at 30 µg/mL. It also exhibited potential antioxidant activities and elastase enzyme inhibition activity (IC50 27.51 ± 1.70 µg/mL). Atmospheric pressure chemical ionization mass spectrometry (APCI–MS) detected more m/z peaks than electrospray ionization mass spectrometry (ESI–MS), and both ionization techniques illustrated the biological activities of the detected compounds more thoroughly compared to single-mode analysis. Our findings suggest that APCI along with ESI is a potential ionization technique for metabolite profiling, and ZLE has the potential in managing diabetes by inhibiting α-glucosidase activity and enhancing glucose uptake.  相似文献   

9.
Glycyrrhiza glabra was liquefied by ethanol and acetone in an autoclave under high pressure using potassium hydroxide or sodium carbonate as the catalyst, as well as without catalyst at various temperatures (250, 270 and 290 °C) for producing bio-oil. The experimental results show that the yield of the main liquefaction product (bio-oil) was influenced significantly by liquefaction parameters such as solvent type, and catalyst type and temperature. The results showed that the maximum bio-oil yield was obtained in acetone (79%) at 290 °C without catalyst. The products of liquefaction (bio-oil) were analysed and characterized using various methods including elemental analysis, Fourier transform infrared spectroscopy and gas chromatography–mass spectrometry. GC–MS identified 131 and 147 different compounds in the bio-oils obtained at 270 and 290 °C, respectively.  相似文献   

10.
In this work, we investigated the peculiar peaks found in the MALDI-TOF mass spectra of polystyrenes (PS) with a bromine end prepared by atom transfer radical polymerization when silver trifluoroacetate (AgTFA) and THF were used as cationization agent and solvent, respectively, in the MALDI sample preparation. In the MALDI mass spectrum, PS with a terminal bromine was not detected but the species with a terminal double bond (U series), and −22 m/z (T series) and +18 m/z (W series) peaks relative to U series appeared as major peaks. While the U species was reported as a result of the elimination reaction of HBr, but the origin and the structure of the other species have not been elucidated. We found that the −22 m/z peak of Un is in fact Tn-2, which is the adduct of THF and the anion of the Ag salt, TFA (+186 m/z) to Un-2. The +18 m/z peak was confirmed to be the species with a terminal OH. All these reactions were catalyzed by Ag salt and the T and W series were not found at all when NaTFA was used as a cationization agent.  相似文献   

11.
The conversions of sulfur-rich asphaltite (the gross-formula CH1.23N0.017S0.037O0.01) in supercritical water (SCW) flow at 400 °C, 30 MPa without and with addition of aluminum and zinc shavings to asphaltite have been studied. At SCW conversion of asphaltite without addition of metals the yields of volatile and liquid products were found to be equal to 10.3 and 46.0%, respectively. The amount of oil in the liquid product was by 1.6 times higher than that in raw asphaltite. Hydrogen evolution during the oxidation of 〈Al〉 and 〈Zn〉 by supercritical water provided for the hydrogenation of asphaltite in situ. When 〈Al〉 and 〈Zn〉 were added, the portion of the insoluble conversion residue decreased from 44.5 up to 11.3 and 26.3%, respectively. The degree and efficiency of asphaltite hydrogenation with addition of 〈Al〉 were higher than the ones with addition of 〈Zn〉. The amount of O-containing substances in the products and the conversion residue was found to have increased as compared with raw asphaltite. At conversion without addition of metals, the bulk of oxygen was mainly concentrated in the conversion residue, while with addition of 〈Al〉 and 〈Zn〉 it was detected in the composition of CO and CO2. According to the GC–MS, IR and NMR 1H spectroscopy data, addition of metals to asphaltite resulted in decrease in the content of sulfoxides and carbonyl-containing substances and in increase in the content of polyaromatic substances in the liquid products. When 〈Al〉 was added to asphaltite, more than 70% of sulfur passed into H2S and when 〈Zn〉 was added, more than 60% of sulfur passed into ZnS.  相似文献   

12.
Elemental compositions of components in feed and catalytically processed deasphalted oils were characterized by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). The processed oils which were hydrocracked over a zeolite catalyst at three different reaction temperatures (370, 380, and 390 °C) were analyzed. Species of the deasphalted oils were ionized either by electrospray ionization (ESI) or by in-beam electron ionization (EI). The ESI mass spectra were obtained from every feed and processed deasphalted oil. Over 550 chemically different compounds were observed in the feed oil mass spectra. Molecular formulas for the detected peaks were calculated by using accurate mass. The compounds with one N atom as well as one N and S atoms were detected as major and minor component, respectively, in every mass spectrum. The number of the detected species in processed deasphalted oil decreases as the reaction temperature increases. However, the carbon distribution of NS-containing species shifts to high number as the reaction temperature increases. Molecular formulas distribution against Z-value (Z-value is defined as CnH2n + ZNmSsOo) and C-number were investigated for the ESI mass spectra. Z-value distribution of the peaks assigned to N-compounds was convergent in its compounds with Z = − 25 as increasing the reaction temperature. Detailed mass spectrum analysis reveals that compounds which were not detected in the feed oil were observed in the mass spectra of processed oils; N, S, and O-containing compounds. For the in-beam EI only the processed oil at 390 °C yields approximately 700 resolved peaks at adopted probe temperature (300 °C) of EI. Molecular formula analysis for the observed peaks was conducted as well as ESI. It reveals that the molecular formulas having Z-value (− 30 < Z < 2) and carbon number ranged from 8 to 31 except for (− 18 < Z < − 12, 15 < C-number < 22) were contained in the processed deasphalted oil. Using complementary ionization techniques to characterize the feed and catalytic reacted deasphalted oils provide better understanding of fuel processing conditions.  相似文献   

13.
The use of the new psychoactive substances is continuously growing and the implementation of accurate and sensible analysis in biological matrices of users is relevant and fundamental for clinical and forensic purposes. Two different analytical technologies, high-sensitivity gas chromatography-mass spectrometry (GC-MS) and ultra-high-performance liquid chromatography-high-resolution mass spectrometry (UHPLC-HRMS) were used for a screening analysis of classic drugs and new psychoactive substances and their metabolites in urine of formed heroin addicts under methadone maintenance therapy. Sample preparation involved a liquid-liquid extraction. The UHPLC-HRMS method included Accucore™ phenyl Hexyl (100 × 2.1 mm, 2.6 μm, Thermo, USA) column with a gradient mobile phase consisting of mobile phase A (ammonium formate 2 mM in water, 0.1% formic acid) and mobile phase B (ammonium formate 2 mM in methanol/acetonitrile 50:50 (v/v), 0.1% formic acid) and a full-scan data-dependent MS2 (ddMS2) mode for substances identification (mass range 100–1000 m/z). The GC-MS method employed an ultra-Inert Intuvo GC column (HP-5MS UI, 30 m, 250 µm i.d, film thickness 0.25 µm; Agilent Technologies, Santa Clara, CA, USA) and electron-impact (EI) mass spectra were recorded in total ion monitoring mode (scan range 40–550 m/z). Urine samples from 296 patients with a history of opioid use disorder were examined. Around 80 different psychoactive substances and/or metabolites were identified, being methadone and metabolites the most prevalent ones. The possibility to screen for a huge number of psychotropic substances can be useful in suspected drug related fatalities or acute intoxication/exposure occurring in emergency departments and drug addiction services.  相似文献   

14.
Thermochemical liquefaction characteristics of Spirulina, a kind of high-protein microalgae, were investigated with the sub- and supercritical ethanol as solvent in a 1000 mL autoclave. The influences of various liquefaction parameters on the yields of products (bio-oil and residue) from the liquefaction of Spirulina were studied, such as the reaction temperature (T), the S/L ratio (R1, solid: Spirulina, liquid: ethanol), the solvent filling ratio (R2) and the type and dosage of catalyst. Without catalyst, the bio-oil yields were in the range of 35.4 wt.% and 45.3 wt.% depending on the changes of T, R1 and R2. And the bio-oil yields increased generally with increasing T and R2, while the bio-oil yields reduced with increasing R1. The FeS catalyst was certified to be an ideal catalyst for the liquefaction of Spirulina microalgae for its advantages on promoting bio-oil production and suppressing the formation of residue. The optimal dosage of catalyst (FeS) was ranging from 5-7 wt.%. The elemental analyses and FT-IR and GC-MS measurements for the bio-oils revealed that the liquid products have much higher heating values than the crude Spirulina sample and fatty acid ethyl ester compounds were dominant in the bio-oils, irrespective of whether catalyst was used.  相似文献   

15.
A. Donatelli  P. Iovane 《Fuel》2010,89(10):2721-2728
This paper presents experimental and numerical results on steam gasification of waste tyres in a rotary kiln pilot plant. Both the process performance and the gas features have been evaluated varying the feeding ratio (FR), defined as the steam/tyres mass ratio. First, several experimental tests have been performed. Then, the obtained experimental results have been used to verify the consistency of a numerical model developed with the aid of the commercial code ChemCAD®. Once done, the effect of increasing the FR on the gas energy content has been evaluated.Numerical results showed that the gas energy content increases as the FR increases as well, achieving a maximum value for FR = 0.33 that produced a gas which composition N2 free is (H2 = 52.7%vol, CO = 18.1%vol, CO2 = 7.0%vol, CH4 = 22.2%vol) in correspondence of which the lower heating value (LHV) is equal to 29.5 MJ kggas−1. Higher FR values do not produce a further increase of the gas energy content, rather require a greater amount of input energy for heating the steam from the atmospheric to the process temperature.  相似文献   

16.
P. E. Kolattukudy 《Lipids》1970,5(4):398-402
Surface lipid of pea leaves (Pisum sativum var. Frosty) was analyzed with column, thin layer and gas liquid chromatography in conjunction with mass spectrometry and infrared spectroscopy. It contained 42%n-hentriacontane and 7.3%n-hentriacontan-16-ol. About 5% was wax esters, C40–C50 consisting of primarily C26 and C28 alcohols and C16–C22 acids. Almost 5% was aldehydes, mainly C26 and C28. Primary alcohols, chiefly C26 and C28, made up 20% of the surface lipid.  相似文献   

17.
This paper describes catalytic investigations into soot oxidation over KOH, K2CO3, KNO3, CH3COOK and K2SO4 doped iron and manganese spinels. For Fe3O4 it was found that alkali doping (0.5 monolayer) is confined to the surface and results in the substantial enhancement of its catalytic activity (ΔT50%  80 °C for K2CO3), depending on the precursor nature. For Mn3O4 K-doping at low loading (0.5 ML) has a negative effect, whereas at high loading (9 ML) leads to the formation of a birnessite shell on the Mn3O4 core catalyst with a spectacular increase of the soot oxidation rate (ΔT50%  150 °C).  相似文献   

18.
《Diamond and Related Materials》2003,12(10-11):1908-1911
A heterofullerene in which carbon atoms of the fullerene cage are substituted by heteroatoms (boron and nitrogen) was synthesized by BN substitution reaction of fullerene C60 upon irradiation with a KrF excimer laser at room temperature. The products were purified by a high performance liquid chromatography and analyzed with a double focusing mass and mass/mass spectrometer, revealing that BNC58 (m/z 721) was formed. The existence of boron and nitrogen in the product was confirmed by X-ray photoelectron spectroscopy and 13C NMR analyses. Moreover, 11B NMR spectrum of the sample indicated the existence of BN bond in the compound.  相似文献   

19.
Poly[methyl methacrylate(81)/butyl acrylate(19)] copolymer was exposed to atmosphere of humidity for various times. The normal α and ρ peak, a third LL peak is observed in thermally stimulated depolarization current (TSDC) spectra of the copolymer. The α peak corresponds to the glass transition, the ρ peak originates from the detrapping of trapped carriers in the bulk amorphous structure, and the LL peak can be attributed to the charge detrapping related to the liquid–liquid transition of the copolymer. The three peaks all move to lower temperature with an increase of the moisture content, indicating that the flexible moisture content not only has an effect of plasticization on the glass transition and liquid–liquid transition, but also makes the trap depth of ρ peak shallower. The trap depth of ρ peak is affected by the introduction of moisture content and the degree of hydration of the copolymer. Based on analysis of calculated results, it was confirmed that the relaxation time of LL peak obeys VF equation when temperature is below T LL.  相似文献   

20.
Melia azedarach L. is a plant with wide use in folk medicine since it contains many bioactive compounds of interest. The present study aimed to extract bioactive compounds from M. azedarach fruits by a sequential process in fixed bed using various solvent mixtures. Extractions were performed at 50 °C and 300 bar in four sequential steps using supercritical CO2 (scCO2), scCO2/ethanol, pure ethanol, and ethanol/water mixture as solvents, respectively. The efficacy of the extraction process was evaluated by extraction yield and kinetics, and analysis of extracts by: (1) thin layer chromatography (TLC), (2) phenolics content, (3) reduction of surface tension of water, (4) gas chromatography (GC–MS), (5) electrospray ionization mass spectrometry (ESI–MS) and (6) antiviral activity. The overall extraction yield reached 45% and TLC analysis showed extracts with different composition. extract obtained from CO2/ethanol mixture (SCEE) exhibited the greatest ability to reduce surface tension of water from 72.4 mN m−1 [1] of pure water to 26.9 mN m−1 of an aqueous solution of 40 g L−1. The highest phenolics contents were observed in both the hydroalcoholic extract and scCO2/ethanolic extract. Volatile oils were not detected in the supercritical extracts by GC–MS. MS analyses identified the fatty acids: linoleic, palmitic and myristic acid in the supercritical extract (SCE), and the phenolics: caffeic acid and malic acid in the other extracts. In addition, SCE and SCEE extracts showed significant inhibition percentage against Herpes Simplex Virus Type 1. The extraction process proposed in the present study produced extracts with significant potential for application in food and pharmaceutical industries.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号