Pyrolysis of Residual Tobacco Seeds: Characterization of Nitrogen Compounds in Bio-oil Using Comprehensive Two-Dimensional Gas Chromatography with Mass Spectrometry Detection (original) (raw)
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Journal of Analytical and Applied Pyrolysis, 2012
The use of bio oil of fast pyrolysis of agricultural and industrial residues may be an economically and environmentally friendly choice for generation of energy and also for the production of chemicals. Suitable applications of rice husk and peach pit are an important issue to avoid improper waste disposal, as Brazilian production of rice and peach reach significant values. The purpose of this work was to perform a detailed qualitative analysis of bio oils of rice husk and peach pit, taking advantage of the higher peak capacity, resolution, sensitivity and selectivity of two-dimensional gas chromatography with mass spectrometric detector (GC × GC/TOFMS). The total number of compounds detected by GC × GC/TOFMS was 503 and 705 for rice husk and peach pit pyrolysates, respectively. Compounds tentatively identified in the same matrices were 106 and 223, respectively. Bio oil compounds were classified in five groups: phenols ketones, acids, ethers, aldehydes, and others. Major classes of both bio oils were phenols and ketones and the major compounds of rice husk and peach pit pyrolysates were guaiacol and furfural, respectively. Twenty compounds (area > 1%) of rice husk bio oil and 25 of peach pit oil accounted for 74.04% and 63.62% of the total area, respectively. A structured distribution of compounds of some classes was observed in the two dimensional space, as for example phenols and ketones. Qualitative analysis of these bio oils by GC × GC provided a detailed knowledge of their composition. Both bio oils showed might be employed for the production of chemicals and may be upgraded through an improved pyrolysis process.
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There is an increasingly urgent call to shift industrial processes from fossil fuel feedstock to sustainable bio-based resources. This change becomes of high importance considering new budget requirements for a carbon-neutral economy. Such a transformation can be driven by traditionally used plants that are able to produce large amounts of valuable biologically relevant secondary metabolites. Tobacco plants can play a leading role in providing value-added products in remote areas of the world. In this study, we propose a non-exhaustive list of compounds with potential economic interest that can be sourced from the tobacco plant. In order to optimize extraction methodologies, we first analyzed their physico-chemical properties using rapid solubility tests and high-resolution microfractionation techniques. Next, to identify an optimal extraction for a selected list of compounds, we compared 13 different extraction method–solvent combinations. We proceeded with profiling some of these ...
ACS Sustainable Chemistry & Engineering, 2016
Fast pyrolysis bio-oils are feasible energy carriers and a potential source of chemicals. Detailed characterization of bio-oils is essential to further develop its potential use. In this study, quantitative 13 C nuclear magnetic resonance (13 C NMR) combined with comprehensive two-dimensional gas chromatography (GC × GC) was used to characterize fast pyrolysis bio-oils originated from pinewood, wheat straw, and rapeseed cake. The combination of both techniques provided new information on the chemical composition of bio-oils for further upgrading. 13 C NMR analysis indicated that pinewood-based bio-oil contained mostly methoxy/hydroxyl (≈30%) and carbohydrate (≈27%) carbons; wheat straw bio-oil showed to have high amount of alkyl (≈35%) and aromatic (≈30%) carbons, while rapeseed cakebased bio-oil had great portions of alkyl carbons (≈82%). More than 200 compounds were identified and quantified using GC × GC coupled to a flame ionization detector (FID) and a time of flight mass spectrometer (TOF-MS). Nonaromatics were the most abundant and comprised about 50% of the total mass of compounds identified and quantified via GC × GC. In addition, this analytical approach allowed the quantification of high value-added phenolic compounds, as well as of low molecular weight carboxylic acids and aldehydes, which exacerbate the unstable and corrosive character of the bio-oil.
Natural Drugs from Plants
Mass spectrometry is one of the best techniques for analyzing the structure of a molecule. It usually provides information about the molecular weight of a substance, and it can present atomic mass units and up to ten thousandths of atomic mass units depending on the accuracy of the mass analyzer. In addition, it provides information on the positive ions formed in the ionization process, which is linked to the chemical structure of the molecule and the nature of the bonds. This technique is widely used for analyzing compounds from natural products. The development of the technique combined with the use of software and databases has been remarkable in recent years, improving the ionization processes and the ion analysis. Since natural products generally constitute a mixture of a complex quantity of components, mechanisms have been developed for coupling to chromatographic techniques of various kinds. This review aims to show how mass spectrometry has contributed to the qualitative qua...
Chemical Composition of Bio-oils Produced by Fast Pyrolysis of Two Energy Crops †
Energy & Fuels, 2008
Bio-oils from the fast pyrolysis of switchgrass forage and two sets of alfalfa stems (from two stages of developmentsbud and full flower stages) have been analyzed by wet-chemical methods, GC-MS, and HPLC. The chemical composition of bio-oil is important because it may give insights into its quality, stability, or suitability for downstream upgrading. Pyrolysis experiments were conducted at 500°C under a nitrogen atmosphere in 2.5 kg/h fluidized bed reactor. A total of 62 chemical species were positively identified in the liquids. Of the identified compounds, 27 have been quantified. The chemical compositions of the bio-oils are compared with what is known about the compositions of these feedstocks. While the compositions of the bio-oil from the two alfalfa stems were similar, there were numerous differences in the compositions of the alfalfa and switchgrass bio-oils. Noted are the higher levels of nitrogen, water, and aromatic hydrocarbons in bio-oils produced from alfalfa stems than from switchgrass and woody feedstocks that have been previously characterized. Also noted is a much lower concentration of levoglucosan and hydroxyacetaldehyde concentrations among bio-oils from alfalfa stems compared with bio-oil from switchgrass or woody biomass. Figure 2. Total ion chromatograms for bio-oil from (A) switchgrass forage, (B) early bud alfalfa stems, and (C) full flower alfalfa stems. Labeled peaks are (a) furfural, (b) 2-hydroxy-3-methyl-2-cyclopenten-1-one, (c) phenol, (d) guiaicol, (e) cresols, (f) isoeugenol, and (g) levoglucosan.