Catalytic Pyrolysis Of Cellulose Research Articles

Catalytic co-pyrolysis of cellulose and linear low-density polyethylene over MgO-impregnated catalysts with different acid-base properties

Various MgO impregnated catalysts were used for the catalytic co-pyrolysis (CCP) of cellulose and linear low-density polyethylene (LLDPE) at 600 °C in ambient pressure. Micro reactor-gas chromatography, a semi-batch reactor, was used as a reactor and gas chromatogram/mass spectrometry/flame ionization detector were used for product detection. Three kinds of MgO impregnated catalysts, MgO/Carbon (MgO/C), MgO/Al2O3, and MgO/ZrO2, were prepared by the impregnation of MgO to different supporting materials, C, Al2O3, and ZrO2, respectively. Activities of the three MgO-impregnated catalysts were compared with 1:5 of feedstock to catalyst ratio. MgO/C produced the highest quality oil, which consisted of a large amount of aromatic hydrocarbons during the catalytic pyrolysis (CP) of cellulose. When the MgO catalysts were applied to CCP, the selectivity to aromatic hydrocarbons over MgO/C were 13.42%, which were also much higher than those over the other catalysts, including bulk MgO, demonstrating the effectiveness of the MgO/C catalyst on aromatics formation. Importantly, the experimental BTEXs (benzene, toluene, ethylbenzene, xylenes) yields of CCP over MgO/C were also much higher than the theoretical yields, highlighting the effectiveness of hydrogen-rich LLDPE on the CP of cellulose over MgO/C. Further investigation of the cellulose/LLDPE mixing ratio showed that the amount of BTEXs during the CCP of cellulose and LLDPE could be maximized by adjusting the cellulose to LLDPE mixing ratio to 25:75.

Improvement of aromatics production from catalytic pyrolysis of cellulose over metal-modified hierarchical HZSM-5

Metal modification on hierarchical HZSM-5 produced by alkaline desilication was adopted to improve aromatics production from catalytic pyrolysis of cellulose. The influence of alkali concentration in the desilication on catalytic performance of zeolites was first studied. Mild alkaline treatment preserved the micropore structure and acid sites of zeolites when introducing mesopores, while further increase of alkali concentration destroyed the micropores and acidity. The HZSM-5 desilicated by 0.3 M NaOH solution had the best catalytic performance, which increased the aromatics production and BTX selectivity. Then, metal (Fe and Ga) modification on the optimal zeolite was used to further improve the catalytic performance. Fe modification showed negative effect on aromatics production while Ga modification had the positive. Both Fe and Ga modification increased the selectivity of monoaromatics at the expense of polyaromatics. Furthermore, Fe modification mainly enhanced the production of BTX, while Ga modification promoted the formation of both BTX and alkylbenzenes.

Catalytic pyrolysis of cellulose in ionic liquid [bmim]OTf

This study discussed the catalytic cracking process of cellulose in ionic liquid 1-butyl-3-methylimidazolium trifluoromethanesulfonate ([bmim]OTF) under 180°C, 240°C and 340°C, found that [bmim]OTF is an effective catalyst which can effectively reduce the pyrolysis temperature(nearly 200°C) of the cellulose. FRIR, XRD and SEM were used to analyze the structure characterization of fiber before and after the cracking; GC–MS was used for liquid phase products analysis; GC was used to analyze gas phase products. The results showed that the cellulose pyrolysis in [bmim]OTf mainly generated CO2, CO and H2, also generated 2-furfuryl alcohol, 2,5-dimethyl-1,5-diallyl-3-alcohol, 1,4-butyrolactone, 5-methyl furfural, 4-hydroxy butyric acid, vinyl propionate, 1-acetoxyl group-2-butanone, furan formate tetrahydrofuran methyl ester liquid product, and thus simulated the evolution mechanism of cellulose pyrolysis products based on the basic model of cellulose monomer.

Muscarine-like compounds derived from a pyrolysis product of cellulose.

Cellulose represents a key component of a renewable biomass source, from which chiral compounds with a high added value in the application for the synthesis of potentially bioactive molecules can be obtained. The anhydrosugar (1R,5S)-1-hydroxy-3,6-dioxa-bicyclo[3.2.1]octan-2-one (LAC), produced on the gram-scale by catalytic pyrolysis of cellulose, was used as a building block in the synthesis of five new enantiomerically pure muscarine-like products. The structures of the target compounds 4-8 showed different substituents at the C-2 and C-4 positions, but each of them had the same (2S,4R) configuration as the natural (+)-muscarine. A renewed interest in new muscarinic analogues is due to the design and synthesis of molecules exhibiting a higher selectivity for a specific muscarinic receptor and due to the development of effective agents in the treatment of Alzheimer's disease and other cognitive disorders. In this context, products 4-8 were investigated with respect to their binding affinity to human M1-M5 muscarinic acetylcholine receptors. The data indicated that compound 8, emerging as the most active in the series with values comparable to natural (+)-muscarine and a moderate selectivity in favor of the hM2 subtype receptor, also exhibited the highest stability during the interaction with the hM2 (3UON) subtype muscarinic receptor by using a docking calculation.

Upgraded production of (1R,5S)-1-hydroxy-3,6-dioxa-bicyclo[3.2.1]octan-2-one from cellulose catalytic pyrolysis and its detection in bio-oils by spectroscopic methods

Catalytic pyrolysis of cellulose was carried out focusing on the selective production of the anhydrosugar (1R,5S)-1-hydroxy-3,6-dioxa-bicyclo[3.2.1]octan-2-one (LAC), a promising chiral chemical for application in organic synthesis. The catalyst Sn-MCM-41, montmorillonite K10 or aluminum titanate nanopowder was used by a suitable pyrolysis reactor performing the processes at 500°C and 350°C. After a workup adapted to optimize the production of LAC and to facilitate the following purification, its amount in the produced bio-oil samples was established by 1H NMR spectroscopy using the standard-addition method. A further quantitative analysis was based on FT-IR technique performed using a CaF2 liquid cell and employing the calibration-curve method. Both the methods, which do not require any pre-treatment steps, provided comparable values (±1%) in terms of LAC abundance in bio-oil samples and validation of the FT-IR based method made it a rapid and efficient tool for quantitative LAC detection also without need of carbonyl band deconvolution. The data showed that (i) Sn-MCM-41 promoted the highest LAC production by pyrolysis at 500°C (7.6±0.1wt.% from cellulose), with a lower than 1% decrease in the presence of this catalyst after a regeneration cycle, and (ii) the cheap and eco-friendly montmorillonite K10 emerged as the best alternative, with a yield from cellulose of 4.8±0.1wt.% at 500°C and 4.6±0.1wt.% at 350°C.

Catalytic conversion of cellulose over mesoporous Y zeolite.

Mesoporous Y zeolite (Meso-Y) was applied, for the first time, to the catalytic pyrolysis of cellulose which is a major constituent of lignocellulosic biomass, to produce high-quality bio-oil. A representative mesoporous catalyst Al-MCM-41 was also used to compare its catalytic activity with that of Meso-Y. Pyrolysis-gas chromatography/mass spectrometry was used for the experiments. Meso-Y, with higher acidity, led to larger yields of aromatics and furans with high value-added than Al-MCM-41, resulting in the production of bio-oil with higher quality. The effect of temperature on the catalytic pyrolysis was not significant within the range of 400-500 degrees C. When the Meso-Y to cellulose ratio was increased from 1/1 via 2/1 to 3/1, the deoxygenation efficiency increased, leading to increased yield of aromatics.

Upgrading of oils derived from hydrothermal treatment of microalgae by catalytic cracking over H-ZSM-5: A comparative Py–GC–MS study

Hydrothermal Treatment (HTT) of microalgae produces an organic liquid (HTT oil) with potentiality as feedstock in biofuel development. Through this process, an oil with oxygen content intermediate between pyrolysis oil from lignocellulosic biomass and fossil oil can be obtained even from lipid-poor microalgal species. However, the elevated content of nitrogen-containing organic compounds derived from algal proteins represents one of the main drawbacks. In this study, catalytic pyrolysis of HTT oil with H-ZSM-5 zeolite was investigated as an upgrading process, in order to reduce the nitrogen content and improve fuel quality. Oils obtained at various HTT experimental conditions from Desmodesmus sp. were mixed with H-ZSM-5 and pyrolyzed at 600°C within a Py–GC–MS system for the analysis of the evolved pyrolysis products. The results were compared with those resulting from catalytic pyrolysis of cellulose, n-hexatriacontane (C36H74) and pyrolysis oils from poplar (original and after hydrogenation). The relative comparison showed that hydrocarbon yields from pyrolysis of HTT oils over H-ZSM-5 were intermediate between those of hexatriacontane and cellulose. The high nitrogen content of the HTT oils did not show any marked effect on yields of hydrocarbons and nitrogen removal was remarkably high in all the investigated HTT oils. Although the data should be confirmed on larger scale, and recycling of catalyst has to be proven, obtained results indicate that it would be possible to introduce HTT oil from microalgae in existing refineries.

Feasibility of broadening the feedstock choice for levoglucosenone production by acid pre-treatment of wood and catalytic pyrolysis of the obtained lignocellulose

Levoglucosenone (LGO) (6,8-dioxabicyclo[3.2.1]oct-2-en-4-one) is commonly produced by synthetic preparation and catalytic pyrolysis of cellulose, both. Feasibility of LGO production from birch lignocellulose (LC) as well as birch and pine wood was studied by analytical pyrolysis. We found that the presence of elevated amounts of lignin and the full or partial elimination of hemicelluloses favor LGO formation during orthophosphoric acid catalyzed LC pyrolysis at 375°C. The yield of LGO reached up to 29–30rel.% from LC pyrolysis products. A known positive effect of lignin on the thermal stability of cellulose during the heating stage prior to the stage of the active decomposition of cellulose was demonstrated. An increased LGO yield from the cellulose mass unit in bulk of wood and LC in comparison with isolated cellulose was observed. The process of LGO production is promising as a method for LC utilization in a complex enterprise of wood hydrothermal processing into chemicals.

Catalytic effects of copper(II) chloride and aluminum chloride on the pyrolytic behavior of cellulose

The cellulose without and with catalyst (CuCl2, AlCl3) was subjected to pyrolysis at temperatures from 350 to 500°C with different heating rate (10°C/min, 100°C/s) to produce bio-oil and selected chemicals with high yield. The pyrolytic oil yield was in the range of 37–84wt% depending on the temperature, the heating rate and the amount of metal chloride. The non-catalytic fast pyrolysis at 500°C gives the highest yield of bio-oil. The mixing cellulose with both metal chlorides results with a significant decrease of the liquid product. The non-catalytic pyrolysis of cellulose gives the highest mass yield of levoglucosan (up to 11.69wt%). The great influence of metal chloride amount on the distribution of bio-oil components was observed. The copper(II) chloride and aluminum chloride addition to cellulose clearly promotes the formation of levoglucosenone (up to 3.61wt%), 1,4:3,6-dianhydro-α-d-glucopyranose (up to 3.37wt%) and unidentified dianhydrosugar (MW=144; up to 1.64wt%). Additionally, several other compounds have been identified but in minor quantities. Based on the results of the GC–MS, the effect of pyrolysis process conditions on the productivity of selected chemicals was discussed. These results allowed to create a general model of reactions during the catalytic pyrolysis of cellulose in the presence of copper(II) chloride and aluminum chloride.

Catalytic pyrolysis of cellulose with sulfated metal oxides: A promising method for obtaining high yield of light furan compounds

Pyrolysis-gas chromatography/mass-spectrometry (Py-GC/MS) was employed to achieve fast pyrolysis of cellulose and on-line analysis of the pyrolysis vapors. Three sulfated metal oxides ( SO 4 2 - /TiO 2, SO 4 2 - /ZrO 2 and SO 4 2 - /SnO 2) were prepared and used for catalytic cracking of the pyrolysis vapors. The distribution of the pyrolytic products was significantly altered by the catalysts. Those important primary pyrolytic products, such as levoglucosan and hydroxyacetaldehyde, were significantly decreased or even completely eliminated. Meanwhile, the catalysis increased three light furan compounds (5-methyl furfural, furfural and furan) greatly. In regard to the selectivity of the three catalysts, the SO 4 2 - /SnO 2 was the most effective catalyst for obtaining 5-methyl furfural, while the SO 4 2 - /TiO 2 favored the formation of furfural and the SO 4 2 - /ZrO 2 favored the formation of furan.

A novel hydroxy functionalized polyester obtained by ring opening copolymerization of L‐lactide with a pyrolysis product of cellulose

AbstractA hydroxylactone ((1R,5S)‐1‐hydroxy‐3,6‐dioxabicyclo [3.2.1] octan‐2‐one, abbreviated as LAC) obtained from catalytic pyrolysis of cellulose was investigated as a monomer in the synthesis of polyesters by ring‐opening polymerization (ROP) with L‐lactide. Although stannous octoate resulted inactive, ROP initiated by zirconium (IV) acetylacetonate afforded novel copolyesters from LAC and lactide mixtures in the bulk at 110 °C. Copolymers were obtained with different LAC content (from 19 to 45%) with a random microstructure as established by detailed NMR analysis. FTIR spectrometry confirmed the presence in the polymer chain of the OH groups originally present in LAC, which do not react during polymerization due to steric hindrance and inter/intramolecular hydrogen bonding. Reaction with trichloroacetylisocyanide proved that OH groups of the polyesters can be readily derivatized. The application of LAC as a comonomer enables the insertion of the alcohol functionality in polylactide avoiding protection/deprotection steps and potentially expanding the realm of biomaterials affordable from carbohydrate feedstock. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 247–257, 2009

Analytical study on the production of a hydroxylactone from catalytic pyrolysis of carbohydrates with nanopowder aluminium titanate

The hydroxylactone (1 R,5 S)-1-hydroxy-3,6-dioxabicyclo[3.2.1]octan-2-one (LAC) was isolated from the catalytic pyrolysis of cellulose over Lewis acids, such as zinc chloride and more recently nanopowder aluminium titanate (NP AlTi). In this study, the tendency of several carbohydrates to thermally produce LAC without and with NP AlTi was investigated by an analytical procedure employing a heated filament pyrolyser. Products evolved from off-line pyrolysis were collected onto an adsorbent resin (XAD-2), eluted with ethyl acetate and analysed by gas chromatography–mass spectrometry (GC–MS). LAC was detected in the pyrolysates of neat cellulose, starch, lactose, d-glucose, O-methyl-α- d-glucoside, O-methyl-β- d-glucoside, d-mannose and d-galactose. The yields of LAC augmented when pyrolysis was conducted in the presence of 30% NP AlTi, but with significant differences among sugars. Polysaccharides provided the highest yields (5–6%), monosaccharides the lowest (<1%). Low levels of LAC were thermally released from the anhydrosugar levoglucosan (LG) and its 4- O-acetyl derivative (AcLG), but when this latter was pyrolysed with the catalyst produced LAC yields comparable to those of starch and cellulose. Thermogravimetric (TG) and its derivative (DTG) analysis showed a general decrease of decomposition temperatures when the sugar sample was mixed with NP AlTi. The pyrolytic behaviour of the different sugars was rationalized by assuming that ascopyrone P (APP; 1,5-anhydro-4-deoxy- d- glycero-hex-1-en-3-ulose) was the precursor of LAC.

Catalytic pyrolysis of cellulose in sulfolane with some acidic catalysts

Catalytic pyrolysis of cellulose in sulfolane (tetramethylene sulfone) with sulfuric acid or polyphosphoric acid gave levoglucosenone, furfural, and 5-hydroxymethyl furfural (5-HMF) up to 42.2%, 26.9%, and 8.8% (as mol% yield based on the glucose unit), respectively. Pyrolysis behaviors of the intermediates indicated the conversion pathways, and the conversion: levoglucosenone → furfural was found to require water. The control of the water content in the pyrolysis medium was quite effective in controlling the product selectivity between levoglucosenone and furfural: mild vacuum conditions to remove the product water dramatically enhanced the levoglucosenone yield, while steam distillation conditions increased the furfural and 5-HMF yields.