Patent Application
20160326204
The present invention refers to a process for the catalytic fractionation of plant biomass, producing non-pyrolytic bio-oil from lignocellulosic materials in addition to a high-quality pulp comprising cellulose and hemicellulose as a byproduct. The invention utilizes a transition metal catalyst for the treatment of lignocellulosic materials (e.g. wood, straw, sugar cane bagasse and crop residues) in order to convert lignin into a non-pyrolytic bio-oil by hydrogen transfer reactions. The so-obtained non-pyrolytic bio-oil is mainly composed of phenolic compounds (e.g. lignin fragments) presenting a low molecular weight. This feature leads to feedstock easier to process with further catalytic reactions. The high-quality pulp is suitable for paper production and enzymatic saccharification. The inventive process is useful for a variety of interesting applications, leading in a single step to high quality pulp and non-pyrolytic bio-oil that mostly comprises phenols in addition to cyclohexanones, cyclohexanols and cycloalkanes as minor products.
Efficient catalytic processes are required for exploiting alternative sources of carbon (e.g. lignocelluloses) to the fullest, diminishing modern society's reliance on crude oil. In this context, lignocelluloses (e.g. wood, grass, crops residues and several others) show great potential as part of the solution for decreasing the reliance of modern societies on fossil resources. However, the direct conversion of these renewable carbon sources by chemical and biotechnological processes is hindered by their complex polymeric nature. In plant biomass, three polymers—cellulose, hemicellulose and lignin—form a complex and highly recalcitrant composite that creates the plant cell walls. Accordingly, many alternative pathways beginning with lignocellulosic biomass rely upon pyrolysis or gasification processes to extensively break down the highly recalcitrant composite, delivering pyrolysis oil or synthesis gas. While these routes deliver chemical streams that could be further processed by well-known technologies (e.g. hydrotreatment, Fischer-Tropsch synthesis, methanol synthesis, etc), many challenges remain to tackle in order to improve the chemical quality of the lignocellulose-derived streams and take full advantage of the mature technologies for production of synthetic fuels (e.g. Fischer-Tropsch synthesis).
Converting plant biomass into bio-oil by pyrolysis is part of a portfolio of solutions currently in development for the production of engine fuels. In the fast pyrolysis of wood to bio-oil, an increase in energy density by a factor of 7 to 8 is achieved (P. M. Mortensen, J. D. Grunwaldt, P. A. Jensen, K. G. Knudsen and A. D. Jensen, Appl. Catal. A-Gen., 2011, 407, 1-19). In spite of this, with an oxygen-content as high as 40 wt %, bio-oil still has a much lower energy density than crude oil. Furthermore, the high-oxygen content makes bio-oil unstable on storage. Consequently, its viscosity increases and polymeric particles are also formed. To circumvent these problems, the upgrade of bio-oil, decreasing its oxygen-content and its reactivity, is needed. There are two general routes for upgrading bio-oils as discussed in great detail in (P. M. Mortensen, J. D. Grunwaldt, P. A. Jensen, K. G. Knudsen and A. D. Jensen, Appl. Catal. A-Gen., 2011, 407, 1-19), namely hydrodeoxygenation (HDO) and “zeolite cracking”. These routes are outlined as the most promising avenues to convert bio-oils into engine fuels. In HDO processes, bio-oil is subjected to high pressures of H2 (80-300 bar) and to high temperatures (300-400° C.) for reaction times up to 4 h. In the best cases, these processes lead to an 84% yield of oil. The HDO processes are performed with sulfide-based catalysts or noble metal supported catalysts. In the cracking of bio-oil using zeolites, the upgrade is conducted under lower pressures for less than 1 h, but temperatures up to 500° C. are necessary for obtaining yields of oil as high as 24%. In both processes, the severity of the process conditions poses a major problem for the energy-efficient upgrading of bio-oil.
The conversion of the whole plant biomass by pyrolysis not only leads to pyrolytic bio-oils but also to gaseous products in addition to biochar. As matter of fact, a considerable quantity of renewable carbon is then lost by the undesirable formation of gaseous products and biochar.
The pyrolytic pathway completely breaks down the complex biomolecules, albeit part of their structure is useful as building blocks for a number of different target molecules. Efficient approaches for rationally disassembling lignocellulose, in order to incorporate the existing chemical functionalities in the final products, could be more advantageous for biomass utilization for the production of platform chemicals, compared with the biomass pyrolysis.
Envisioning the production of biofuels and platform chemicals from lignocellulose, an ideal fractionation process should provide a carbohydrate fraction (pulp) with low lignin, and a lignin fraction amendable to process under low-severity conditions. Previous technologies in place for wood pulping are not likely to meet the needs for the production of biofuels and platform chemicals from lignocellulose. First, and of utmost importance for the paper industry, the main goal of any pulping process is to deliver high strength fibers of cellulose suitable for paper production and other cellulose-based products. Such cellulose presents a high degree of polymerization and high crystallinity. These properties pose major problems to chemical and enzymatic hydrolytic processes. Second, and of importance for lignocellulose biorefineries, the separation of lignin and hemicellulose from the cellulosic fibers is nowadays performed by the chemical degradation of these valuable biomass fractions. Therefore, in conventional pulping processes a large fraction of the renewable carbon from plant biomass is transformed into even more recalcitrant byproducts (e.g. Kraft lignin), strongly reducing their potential as feedstock for the production of value-added products. Altogether, there is thus a substantial need for novel processes able to fractionate plant biomass, enabling the efficient downstream processing of the fractions toward the production of biofuels and platform chemicals.
Unlike cellulose, lignin has its structure dramatically modified after the pretreatment. The modifications depend upon the fractionation method. The main chemical pulping process is Kraft pulping. In this process, wood is subjected to treatments in the presence of sulfide, sulfhydryl and polysulfide species at high pH, this leads to degradation and solubilization of hemicelluloses and lignin fragments in a so-called black liquor. The high sulfur-content and high degree of condensation of Kraft lignin create obstacles to chemical and material utilization of Kraft lignin for the production of high value-added chemical assets. Therefore, this lignin is generally used as fuel in the pulp and paper industry to recover the inorganic chemicals utilized by the pulping process.
For example, CA 1131415 and its US equivalent U.S. Pat. No. 4,594,130 describe a process for treating lignocellulose with a solvent mixture comprised of water, methyl alcohol, and a dissolved metal salt catalyst in a pressure vessel at a temperature in the range 180° C. to 210° C. to produce a chemical pulp of fibrous material. The metal salt catalyst is a chloride or nitrate of one of the metals calcium, magnesium or barium, and is useful in concentrations between 0.005 molar to 1.0 molar. The functions and effects of the metal salt catalysts are essentially serving both as a proton-generating agent as well as providing protection to the cellulose especially at the later stages of the cooking against degradation by hydrolytic solvolysis. According to said process, the metal salt catalyst shall be recoverable, but the description of the process is silent how to achieve such recovering of the soluble salt from a solution thereof. The process does not make use a metal catalyst, but of metal salt only and thus, the process is different to the process of the present invention.
Another used method of biomass pretreatment is lignosulfonate process. In this case, the lignin obtained has a higher degree of sulfonation, compared with those obtained by the Kraft process.
A promising approach for the separation of lignin from biomass, without the use of sulfur-containing chemicals, is the organosolv process. In this process, delignification of wood is performed by organic solvents. This process has been the subject of considerable research activity since the idea was introduced in the early 20th century. However, much of the research activity has been taking place in recent years. Most of the innovation in this field is directed towards identification of efficient solvent systems and optimum process conditions. Utilization of solid catalysts in combination with solvent extraction of lignin is not described in the literature.
The organosolv process has been examined on a pilot scale as an alternative to the Kraft process in the pulp industry. The raw material is treated with organic solvent, usually a mixture of low molecular weight alcohols (e.g. ethanol) and water, at a temperature between 120 and 250° C. After fractionation, lignin can be burned as sulfur-free fuel in order to provide energy for the process. In the last years, new biorefinery approaches are leading to the conversion of lignin into more valuable products, such as liquid fuel additives or chemicals.
Until recently, very little work has been done to understand the fundamental aspects of these systems, so little detailed information is available on their mechanisms. In contrast, the mechanisms of the Kraft and sulfite pulping processes and their variants have been studied in detail, and there has been considerable basic work on nonaqueous lignin solvolysis, albeit most of it has not been primarily directed towards understanding the related industrial processes. For example, numerous studies have been done for the purpose of elucidating lignin structure by analyzing its solvolysis products. As a result, there is a substantial amount of information that serves as a basis for inferences concerning organosolv pulping mechanisms, and eventually facilitates further development of organosolv pulping technology.
The inventors recognized that the main challenge of conversion of native lignin is the cleavage of the linkages between the monomeric fragments, composed mainly (80%) of ether bonds (X. Wang, R. Rinaldi, ChemSusChem, 2012, 5, 1455-1466). Recent work of the inventors demonstrated that it is possible to perform hydrogenolysis of lignin model compounds via hydrogen transfer in the presence of skeletal Ni catalyst as catalyst and 2-propanol (2-PrOH) as a hydrogen-donor (X. Wang, R. Rinaldi, Energy Environ. Sci., 2012, 5, 8244-8260).
The inventors have now discovered that the processing of wood in a mixture of organic solvents in the presence of metal catalyst leads to extraction and deep depolymerization of lignin, yielding a non-pyrolytic bio-oil rich in phenols in addition to a pulp containing cellulose and hemicellulose. No external pressure of molecular hydrogen is supplied to the system. The inventors have developed the present process as a new approach for biomass conversion. In the following, the new process is introduced and subsequently, the analysis of the lignin products obtained by the new process in form of oil is given, thus demonstrating that direct depolymerization of lignin from biomass is possible. A side, but very important aspect of the invention is the production of a pulp in high yields and with low structural modifications from the process. This pulp undergoes enzymatic hydrolysis in the presence of commercial cellulases preparations.
In the inventive process, wood is treated with an organic solvent and H-donor (e.g. secondary alcohols, preferably 2-propanol and 2-butanol), mixtures of different organic solvents (e.g., primary and secondary alcohols) including a mixture thereof with water in the presence of metal catalyst. The process is performed in absence of externally supplied pressure of hydrogen. The reaction mixture can be separated into two fractions, the first one being the non-pyrolytic bio-oil and the second one a solid fraction of pulp.
The H-donor is generally selected from secondary alcohols having 3 to 8 carbon atoms, preferably 2-PrOH, 2-butanol, 2-cyclohexanol or mixtures thereof. Cyclic alkenes, comprising 6 to 10 carbon atoms, preferably cyclohexene, tetraline or mixtures thereof can be used as H-donor. In addition, formic acid can be also used as H-donor. Furthermore, polyols comprising 2 to 9 carbon atoms can be used as H-donor, preferably ethylene glycol, propylene glycols, erythritol, xylitol, sorbitol, mannitol and cyclohexanediols or mixtures thereof. Saccharides selected from glucose, fructose, mannose, xylose, cellobiose and sucrose can be also used as H-donor.
Lignin formed in-situ or added to the system can be used as an H-donor.
As a metal catalyst, any transition metal can be used as much as it is suitable for building up a catalyst skeleton catalyst. The metal catalyst can be suitably a skeletal transition metal catalyst or supported transition metal catalyst or mixture, preferably skeletal nickel, iron, cobalt or copper catalysts or a mixture thereof. Generally, the metal can be selected from nickel, iron, cobalt, copper, ruthenium, palladium, rhodium, osmium iridium, rhenium or mixtures thereof, preferably nickel, iron, cobalt, ruthenium, copper or any mixture thereof. Metal catalysts prepared by the reduction of mixed oxides of the above mentioned elements in combination with aluminum, silica and metals from the Group I and II can also be used in the process.
As an option, the catalyst can be a bifunctional solid comprising metal functionality and acid sites wherein said acid sites being preferably functional sites having acidic Brønsted or Lewis functionality or both.
In an example, the combined process consists of a batch reaction in which wood pellets are treated with organic solvents (2-PrOH, 2-PrOH-water mixtures, 2-PrOH-methanol, 2-PrOH-methanol-water, 2-butanol-methanol, 2-butanol-methanol-water, ethanol-water) with the addition of skeletal Ni catalyst as a catalyst for the depolymerization and reduction of lignin fragments. No gaseous hydrogen is added. The process is performed under autogeneous pressure only. After the process completion, skeletal Ni catalyst is easily separated from the product mixture by means of a magnet, since skeletal Ni catalyst and Ni catalysts show magnetic properties. Other skeletal catalysts having magnetic properties can also be used. The catalyst-free mixture is then filtered in order to separate the solution comprising the raw non-pyrolytic bio-oil and pulp (solid carbohydrate fraction). After distillation of the solvent mixture, the non-pyrolytic bio-oil is isolated.
The advantages of this process over the current state-of-art are several:
In more detail, the present invention refers to a process for production of non-pyrolytic bio-oil rich in phenolic compounds and a pulp rich in cellulose and hemicellulose by H-transfer reactions performed on lignocellulosic substrates in the presence of skeletal Ni catalyst or other metal catalyst in addition to a H-donor (an alcohol) comprising the steps of:
In the inventive process the lignocellulose material is preferably a particulate material and and a biomass such as hardwood, softwood, straw, sugar cane bagasse, perennial grasses and crop residues, and others.
The process can be performed as a one-pot process, that is, substrate and catalyst are suspended in a solvent mixture and cooked at the temperature ranges aforementioned.
Alternatively, the process can be carried out as a multi-stage process in which the liquor obtained from the reaction where the substrate is cooked is continuously transferred into another reactor comprising the catalyst, and the processed liquor returned to the main reactor where the substrate is cooked.
The inventive process is applicable to any type of lignin containing material from any type of hardwood, softwood and perennial grass.
As mentioned above, the solvent system generally comprises an organic solvent or mixtures thereof being miscible with water and is preferably selected from lower aliphatic alcohols having 1 to 6 carbon atoms and one to three hydroxy groups, preferably methanol, ethanol, propanol, 2-propanol and 2-butanol or mixtures thereof. Thus, the solvent system can be a solvent mixture of at least one lower aliphatic alcohol having 1 to 6 carbon atoms and water, preferably in a v/v-ratio of 99.9/0.1 to 0.1/99.9, preferably 10/90 to 90/10, most preferably 20/80 to 80/20, alcohol/water solutions.
In particular, the solvent system is a solvent mixture of secondary alcohols (e.g. 2-PrOH, 2-butanol, cyclohexanol) and water in a v/v-ratio of 80/20 to 20/80, alcohol/water solutions.
Other solvents, such as aliphatic or aromatic ketones having 1 to 10 carbon atoms, ethers having 2 to 10 carbon atoms, cyclohexanols, cyclic ethers (preferably, tetrahydrofuran, methyltetrahydrofurans or dioxanes) and esters (preferably, ethylacetate and methylacetate) can be added into the solvent fraction as modifiers in order to adjust the phenol content in the obtained non-pyrolytic bio-oil. The volume fraction of the modifier in the solvent mixture, also containing secondary alcohol or mixture thereof and eventually water, ranges from 0.1 to 99.9%, preferably 1 to 95%, most preferably 5 to 70
The process operates at weight ratio of catalyst-to-substrate from 0.001 to 10, preferably 0.01 to 5, most preferably 0.05 to 2.
The inventive process can yield a pulp having a content of cellulose of 68 to 84-wt %, a low lignin content 4 to 11-wt % and a high degree of crystallinity of 50-70%.
In the inventive process, the non-pyrolytic bio-oil can show a phenol content of 1 to 99-wt %.
Thus, the present inventors have demonstrated a new and inventive catalytic process for the extraction of lignin from lignocellulosic substrates in the presence of skeletal Ni catalyst and under low-severity conditions. The so-obtained products in the non-pyrolytic bio-oil present a low molecular weight and thus low degree of condensation by C—C and C—O linkages. In addition, these properties leads to a feed easier to process with further catalytic reactions, compared with the polymeric solid organosolv lignin and other technical lignins. A solvent mixture of 2-PrOH and water 70:30 (v/v) at temperatures above 180° C. almost fully extract lignin from the lignocellulosic matrix. In the lignin products, vinyl and carbonylic groups, such as carboxylic acids, ketones, aldehydes, quinones are reduced, while the phenolic structure are largely preserved.
The conditions mentioned above lead also to the best pulp, with high amount of cellulose (68-84 wt %), low lignin content (4-11 wt %) and high crystallinity (above 60%). Analyses of the pulps demonstrate that the structure of the carbohydrate fraction is maintained during the reaction. This process can find interesting applications, leading in a single-step to high quality pulp and valuable lignin products.
The invention is further illustrated by the drawings. In more detail,
Table 1 summarizes the yields of non-pyrolytic bio-oil (lignin products) and pulps recovered from the catalytic fractionation of poplar wood (or other feedstocks) in the presence of skeletal Ni catalyst under varying conditions. Weight yields of non-pyrolytic oil are 13 to 29 wt % relative to initial weight of the substrate (on a dry and ash-free basis). Weight yields of pulp are 52 to 92 wt % relative to initial weight of the substrate (on a dry and ash-free basis). The presence of water in the solvent solution improves the extraction of lignin from lignocellulosic matrix, and consequently increases the yield of non-pyrolytic bio-oil.
a50 bar H2 added
bspruce wood
csugarcane bagasse
Organosolv lignins (
Low molecular weight compounds detected with GPC were analyzed by two dimensional gas-chromatography coupled to a mass spectrometer (GCxGC-MS, for product identification) and to a flame ionization detector (GCxGC-FID, for product semi-quantification). Table 2 summarizes the results obtained by GCxGC-MS of the non-pyrolytic bio-oils. The products from the reference process (organosolv lignin) were non-volatile due to their polymeric nature. The catalytic fractionation of wood in the presence of skeletal Ni catalyst results in non-pyrolytic bio-oils comprising detectable low molecular weight compounds that are volatile and thus analyzable by GCxGC-MS. The non-pyrolytic bio-oils comprise polyols, phenols, methoxyphenols and saturated products thereof. The increase in the process temperature from 160 to 220 ° C. results in further saturation of the phenol products, as shown in Table 2, entries 1 to 4, leading to an increase in the cyclohexanol content (from 3 to 12%). When the catalytic fractionation is performed in 2PrOH at 180 for 3 h (Table 2, entry 5), transfer hydrogenation is enhanced, leading to numerous cyclohexanol products (21%). Despite the higher hydrogenation activity, the product mixture from reaction in 2-PrOH still presents a considerable amount of aromatic compounds (59%, Table 2, entry 5). The reaction in 2-PrOH/MeOH mixture was performed in order to demonstrate an example in which the hydrogenation of aromatic rings is suppressed. Indeed, under these conditions, methoxyphenols are the major products (81%, Table 2, entry 6)
To analyze the composition of the pulps, the materials were quantitatively saccharified with 72 wt % sulfuric acid (as described by J. F. Saeman, J. L. Bubl, E. E. Harris, Industrial and Engineering Chemistry, Analytical Edition, 1945, 17, 35-37). The pulps are mostly composed of polysaccharides (cellulose and hemicelluloses). They constitute about 70 wt % of poplar wood (Table 3, entry 1). Table 3 shows the composition of the poplar wood and their pulps in terms of glucans, xylans and Klason lignin.
astarting material (poplar wood);
borganosolv pulp (reference process);
c2-PrOH/H2O 7:3 (v/v);
d2-PrOH/MeOH 10:1 (v/v)
The organosolv pulp comprises 79.2 ±4.1 wt % cellulose and 11.4 ±2.3 wt % hemicelluloses (Table 3, entry 2). The residual Klason lignin content is 6.9 ±0.8. In the catalytic fractionation process, the increase in temperature from 160 to 220 ° C. (Table 3, entries 3-6) results in an increase in the glucans content (from ca. 57 to 84%) in addition to a decrease in the xylans (from ca. 14 to 7%) and residual Klason lignin contents (from ca. 14 to 4%). The pulps obtained from the experiments in 2-PrOH or 2-PrOH/MeOH contain higher residual Klason lignin content (Table 3, entries 7 and 8) than that obtained from a experiment performed under similar conditions using instead 2-PrOH/H2O 7:3 (v/v) as a process medium.
The crystallinity index (CI) was determined by X-ray diffraction (as reported by S. Park et al. Biotechnology for Biofuels 2010, 3:10).
Enzymatic Saccharification of the Pulps Obtained from Fractionation Under Varying Conditions
The pulps obtained by the catalytic fractionation of lignocellulose in the presence of skeletal Ni catalyst undergo hydrolysis to glucose in the presence of cellulases (Celluclast, Novozymes). The reaction conditions are: substrate (equivalent to 1 g of cellulose), cellulases (Celluclast, 350 U/g substrate), pH 4.7 (acetate buffer), 45° C. Yields relative to the glucan content in each substrate.
The present invention is explained in more detail by way of the following examples.
The following examples are intended to illustrate the present invention without limiting the invention in any way.
Poplar wood (16-17 g, 2 mm pellets, Fa. J. Rettenmaier & Sohne) was suspended in a 140 mL solution of 2-PrOH:water (7:3, v/v) in a 250 mL autoclave equipped with a mechanical stirrer. The suspension was heated from 25 to 160° C. within 1 h under mechanical stirring. The autogenous pressure at 160° C. is 25 bar. The suspension was processed at 160° C. for 3 h. In sequence, the mixture was left to cool down to room temperature. A reddish-brown solution was obtained after filtering off the wood fibers (pulp). The solvent was removed at 60° C. using a rotoevaporator. After solvent removal, a reddish-brown solid was obtained. In turn, the pulp was washed with acetone, and then dried under vacuum evaporation. From 16.7 g of poplar wood, 1.5 g of organosolv lignin and 13.2 g pulp were obtained.
Poplar wood (16-17 g, 2 mm pellets, Fa. J. Rettenmaier & Sohne) was suspended in a 140 mL solution of 2-PrOH:water (7:3, v/v) in a 250 mL autoclave equipped with a mechanical stirrer. The suspension was heated from 25 to 180° C. within 1 h under mechanical stirring. The autogenous pressure at 180° C. is 25 bar. The suspension was processed at 180° C. for 3 h. In sequence, the mixture was left to cool down to room temperature. A reddish-brown solution was obtained after filtering off the wood fibers (pulp). The solvent was removed at 60° C. using a rotoevaporator. After solvent removal, a reddish-brown solid was obtained (
Poplar wood (16-17 g, 2 mm pellets, Fa. J. Rettenmaier & Sohne) was suspended in a 140 mL solution of 2-PrOH:water (7:3, v/v) in a 250 mL autoclave equipped with a mechanical stirrer. The suspension was heated from 25 to 200° C. within 1 h under mechanical stirring. The autogenous pressure at 200° C. is 35 bar. The suspension was processed at 200° C. for 3 h. In sequence, the mixture was left to cool down to room temperature. A reddish-brown solution was obtained after filtering off the wood fibers (pulp). The solvent was removed at 60° C. using a rotoevaporator. After solvent removal, a reddish-brown solid was obtained. In turn, the pulp was washed with acetone, and then dried under vacuum evaporation. From 16.6 g of poplar wood, 5.8 g of organosolv lignin and 8.1 g pulp were obtained.
Poplar wood (16-17 g, 2 mm pellets, Fa. J. Rettenmaier & Sohne) was suspended in a 140 mL solution of 2-PrOH:water (7:3, v/v) in a 250 mL autoclave equipped with a mechanical stirrer. The suspension was heated from 25 to 220° C. within 1 h under mechanical stirring. The autogenous pressure at 220° C. is 45 bar. The suspension was processed at 220° C. for 3 h. In sequence, the mixture was left to cool down to room temperature. A reddish-brown solution was obtained after filtering off the wood fibers (pulp). The solvent was removed at 60° C. using a rotoevaporator. After solvent removal, a reddish-brown solid was obtained. In turn, the pulp was washed with acetone, and then dried under vacuum evaporation. From 16.6 g of poplar wood, 5.4 g of organosolv lignin and 7.4 g pulp were obtained.
Poplar wood (16-17 g, 2 mm pellets, Fa. J. Rettenmaier & Sohne) and skeletal Ni catalyst (10 g, Raney Ni 2800 slurry, Sigma-Aldrich) was suspended in a 140 mL solution of 2-PrOH:water (7:3, v/v) in a 250 mL autoclave equipped with a mechanical stirrer. The suspension was heated from 25 to 160° C. within 1 h under mechanical stirring. The suspension was processed under autogeneous pressure at 160° C. for 3 h. In sequence, the mixture was left to cool down to room temperature. A reddish-brown solution was obtained after filtering off the wood fibers (pulp). The solvent was removed at 60° C. using a rotoevaporator. After solvent removal, a brown oil (non-pyrolytic bio-oil) was obtained. In turn, the pulp was washed with acetone, and then dried under vacuum evaporation. From 16.7 g of Poplar wood, 2.3 g of non-pyrolytic bio-oil and 13.2 g pulp were obtained (Table 1, entry 1).
Poplar wood (16-17 g, 2 mm pellets, Fa. J. Rettenmaier & Sohne) and skeletal Ni catalyst (10 g, Raney Ni 2800 slurry, Sigma-Aldrich) was suspended in a 140 mL solution of 2-PrOH:water (7:3, v/v) in a 250 mL autoclave equipped with a mechanical stirrer. The suspension was heated from 25 to 180° C. within 1 h under mechanical stirring. The suspension was processed under autogeneous pressure at 180° C. for 3 h. In sequence, the mixture was left to cool down to room temperature. A reddish-brown solution was obtained after filtering off the wood fibers (pulp). The solvent was removed at 60° C. using a rotoevaporator. After solvent removal, a brown oil (non-pyrolytic bio-oil,
Poplar wood (16-17 g, 2 mm pellets, Fa. J. Rettenmaier & Sohne) and skeletal Ni catalyst (10 g, Raney Ni 2800 slurry, Sigma-Aldrich) was suspended in a 140 mL solution of 2-PrOH:water (7:3, v/v) in a 250 mL autoclave equipped with a mechanical stirrer. The suspension was heated from 25 to 200° C. within 1 h under mechanical stirring. The suspension was processed under autogeneous pressure at 200° C. for 3 h. In sequence, the mixture was left to cool down to room temperature. A reddish-brown solution was obtained after filtering off the wood fibers (pulp). The solvent was removed at 60° C. using a rotoevaporator. After solvent removal, a brown oil (non-pyrolytic bio-oil) was obtained. In turn, the pulp was washed with acetone, and then dried under vacuum evaporation. From 17.1 g of poplar wood, 3.4 g of non-pyrolytic bio-oil and 10.0 g pulp were obtained (Table 1, entry 3).
Poplar wood (16-17 g, 2 mm pellets, Fa. J. Rettenmaier & Sohne) and skeletal Ni catalyst (10 g, Raney Ni 2800 slurry, Sigma-Aldrich) was suspended in a 140 mL solution of 2-PrOH:water (7:3, v/v) in a 250 mL autoclave equipped with a mechanical stirrer. The suspension was heated from 25 to 220° C. within 1 h under mechanical stirring. The suspension was processed under autogeneous pressure at 220° C. for 3 h. In sequence, the mixture was left to cool down to room temperature. A reddish-brown solution was obtained after filtering off the wood fibers (pulp). The solvent was removed at 60° C. using a rotoevaporator. After solvent removal, a brown oil (non-pyrolytic bio-oil) was obtained. In turn, the pulp was washed with acetone, and then dried under vacuum evaporation. From 16.7 g of poplar wood, 3.9 g of non-pyrolytic bio-oil and 8.6 g pulp were obtained (Table 1, entry 4).
Poplar wood (16-17 g, 2 mm pellets, Fa. J. Rettenmaier & Sohne) and skeletal Ni catalyst (10 g, Raney Ni 2800 slurry, Sigma-Aldrich) was suspended in a 140 mL solution of 2-PrOH in a 250 mL autoclave equipped with a mechanical stirrer. The suspension was heated from 25 to 180° C. within 1 h under mechanical stirring. The suspension was processed under autogeneous pressure at 180° C. for 3 h. In sequence, the mixture was left to cool down to room temperature. A reddish-brown solution was obtained after filtering off the wood fibers (pulp). The solvent was removed at 60° C. using a rotoevaporator. After solvent removal, a brown oil (non-pyrolytic bio-oil) was obtained. In turn, the pulp was washed with acetone, and then dried under vacuum evaporation. From 15.8 g of poplar wood, 2.0 g of non-pyrolytic bio-oil and 13.8 g pulp were obtained (Table 1, entry 5).
Poplar wood (16-17 g, 2 mm pellets, Fa. J. Rettenmaier & Sohne) and skeletal Ni catalyst (10 g, Raney Ni 2800 slurry, Sigma-Aldrich) was suspended in a 140 mL solution of 2PrOH:MeOH (10:1, v/v) in a 250 mL autoclave equipped with a mechanical stirrer. The suspension was heated from 25 to 180° C. within 1 h under mechanical stirring. The suspension was processed under autogeneous pressure at 180° C. for 3 h. In sequence, the mixture was left to cool down to room temperature. A reddish-brown solution was obtained after filtering off the wood fibers (pulp). The solvent was removed at 60° C. using a rotoevaporator. After solvent removal, a brown oil (non-pyrolytic bio-oil) was obtained. In turn, the pulp was washed with acetone, and then dried under vacuum evaporation. From 16.7 g of poplar wood, 2.1 g of non-pyrolytic bio-oil and 14,7 g pulp were obtained (Table 1, entry 6).
Poplar wood (16-17 g, 2 mm pellets, Fa. J. Rettenmaier & Sohne) and skeletal Ni catalyst (10 g, Raney Ni 2800 slurry, Sigma-Aldrich) was suspended in a 140 mL solution of 2-PrOH:water (9:1, v/v) in a 250 mL autoclave equipped with a mechanical stirrer. The suspension was heated from 25 to 180° C. within 1 h under mechanical stirring. The suspension was processed under autogeneous pressure at 180° C. for 3 h. In sequence, the mixture was left to cool down to room temperature. A reddish-brown solution was obtained after filtering off the wood fibers (pulp). The solvent was removed at 60° C. using a rotoevaporator. After solvent removal, a brown oil (non-pyrolytic bio-oil,
Poplar wood (16-17 g, 2 mm pellets, Fa. J. Rettenmaier & Sohne) and skeletal Ni catalyst (10 g, Raney Ni 2800 slurry, Sigma-Aldrich) was suspended in a 140 mL solution of 2-PrOH:water (8:2, v/v) in a 250 mL autoclave equipped with a mechanical stirrer. The suspension was heated from 25 to 180° C. within 1 h under mechanical stirring. The suspension was processed under autogeneous pressure at 180° C. for 3 h. In sequence, the mixture was left to cool down to room temperature. A reddish-brown solution was obtained after filtering off the wood fibers (pulp). The solvent was removed at 60° C. using a rotoevaporator. After solvent removal, a brown oil (non-pyrolytic bio-oil,
Poplar wood (16-17 g, 2 mm pellets, Fa. J. Rettenmaier & Sohne) and skeletal Ni catalyst (10 g, Raney Ni 2800 slurry, Sigma-Aldrich) was suspended in a 140 mL solution of 2-PrOH:water (5:5, v/v) in a 250 mL autoclave equipped with a mechanical stirrer. The suspension was heated from 25 to 180° C. within 1 h under mechanical stirring. The suspension was processed under autogeneous pressure at 180° C. for 3 h. In sequence, the mixture was left to cool down to room temperature. A reddish-brown solution was obtained after filtering off the wood fibers (pulp). The solvent was removed at 60° C. using a rotoevaporator. After solvent removal, a brown oil (non-pyrolytic bio-oil,
Poplar wood (2 g, 2 mm pellets, Fa. J. Rettenmaier & Sohne) and skeletal Ni catalyst (1 g, Raney Ni 2800 slurry, Sigma-Aldrich) was suspended in a 14 mL solution of 2-PrOH:H2O (7:3, v/v) in a 35 mL autoclave equipped with a mechanical stirrer. The suspension was heated from 25 to 200° C. within 1 h under mechanical stirring. The suspension was processed under H2 pressure (50 bar) at 200° C. for 3 h. In sequence, the mixture was left to cool down to room temperature. A reddish-brown solution was obtained after filtering off the wood fibers (pulp). The solvent was removed at 60° C. using a rotoevaporator. After solvent removal, a brown oil (non-pyrolytic bio-oil) was obtained. In turn, the pulp was washed with acetone, and then dried under vacuum evaporation. From 2 g of poplar wood, 0.6 g of non-pyrolytic bio-oil and 1.0 g pulp were obtained (Table 1, entry 10).
Poplar wood (2 g, 2 mm pellets, Fa. J. Rettenmaier & Sohne) and skeletal Ni catalyst (1 g, Raney Ni 2800 slurry, Sigma-Aldrich) was suspended in a 14 mL solution of ethanol:H2O (7:3, v/v) in a 35 mL autoclave equipped with a mechanical stirrer. The suspension was heated from 25 to 200° C. within 1 h under mechanical stirring. The suspension was processed under autogeneous pressure at 200° C. for 3 h. In sequence, the mixture was left to cool down to room temperature. A reddish-brown solution was obtained after filtering off the wood fibers (pulp). The solvent was removed at 60° C. using a rotoevaporator. After solvent removal, a brown oil (non-pyrolytic bio-oil) was obtained. In turn, the pulp was washed with acetone, and then dried under vacuum evaporation. From 2 g of poplar wood, 0.6 g of non-pyrolytic bio-oil and 1.1 g pulp were obtained (Table 1, entry 11).
Poplar wood (2 g, 2 mm pellets, Fa. J. Rettenmaier & Sohne) and skeletal Ni catalyst (1 g, Raney Ni 2800 slurry, Sigma-Aldrich) was suspended in a 14 mL solution of EtOH:H2O (7:3, v/v) in a 35 mL autoclave equipped with a mechanical stirrer. The suspension was heated from 25 to 200° C. within 1 h under mechanical stirring. The suspension was processed under H2 pressure (50 bar) at 200° C. for 3 h. In sequence, the mixture was left to cool down to room temperature. A reddish-brown solution was obtained after filtering off the wood fibers (pulp). The solvent was removed at 60° C. using a rotoevaporator. After solvent removal, a brown oil (non-pyrolytic bio-oil) was obtained. In turn, the pulp was washed with acetone, and then dried under vacuum evaporation. From 2 g of poplar wood, 0.6 g of non-pyrolytic bio-oil and 1.1 g pulp were obtained (Table 1, entry 12).
Spruce wood (16-17 g, 2 mm pellets, Fa. J. Rettenmaier & Sohne) was suspended in a 140 mL solution of 2-PrOH:water (7:3, v/v) in a 250 mL autoclave equipped with a mechanical stirrer. The suspension was heated from 25 to 180° C. within 1 h under mechanical stirring. The autogenous pressure at 180° C. is 25 bar. The suspension was processed at 180° C. for 3 h. In sequence, the mixture was left to cool down to room temperature. A reddish-brown solution was obtained after filtering off the wood fibers (pulp). The solvent was removed at 60° C. using a rotoevaporator. After solvent removal, a reddish-brown solid was obtained. In turn, the pulp was washed with acetone, and then dried under vacuum evaporation. From 16.8 g of spruce wood, 2.2 g of organosolv lignin and 13.2 g pulp were obtained.
Spruce wood (16-17 g, 2 mm pellets, Fa. J. Rettenmaier & Sohne) and skeletal Ni catalyst (10 g, Raney Ni 2800 slurry, Sigma-Aldrich) was suspended in a 140 mL solution of 2-PrOH:MeOH (10:1, v/v) in a 250 mL autoclave equipped with a mechanical stirrer. The suspension was heated from 25 to 180° C. within 1 h under mechanical stirring. The suspension was processed under autogeneous pressure at 180° C. for 3 h. In sequence, the mixture was left to cool down to room temperature. A reddish-brown solution was obtained after filtering off the wood fibers (pulp). The solvent was removed at 60° C. using a rotoevaporator. After solvent removal, a brown oil (non-pyrolytic bio-oil) was obtained. In turn, the pulp was washed with acetone, and then dried under vacuum evaporation. From 16.8 g of spruce wood, 2.4 g of non-pyrolytic bio-oil and 11.6 g pulp were obtained (Table 1, entry 13).
Sugarcane bagasse (6-7 g, 2 mm pellets) was suspended in a 140 mL solution of 2-PrOH:water (7:3, v/v) in a 250 mL autoclave equipped with a mechanical stirrer. The suspension was heated from 25 to 180° C. within 1 h under mechanical stirring. The autogenous pressure at 180° C. is 25 bar. The suspension was processed at 180° C. for 3 h. In sequence, the mixture was left to cool down to room temperature. A reddish-brown solution was obtained after filtering off the fibers (pulp). The solvent was removed at 60° C. using a rotoevaporator. After solvent removal, a reddish-brown solid was obtained. In turn, the pulp was washed with acetone, and then dried under vacuum evaporation. From 6.2 g of sugarcane bagasse, 1.3 g of organosolv lignin and 4.8 g pulp were obtained.
Sugarcane bagasse (6-7 g, 2 mm pellets) and skeletal Ni catalyst (10 g, Raney Ni 2800 slurry, Sigma-Aldrich) was suspended in a 140 mL solution of 2-PrOH:MeOH (10:1, v/v) in a 250 mL autoclave equipped with a mechanical stirrer. The suspension was heated from 25 to 180° C. within 1 h under mechanical stirring. The suspension was processed under autogeneous pressure at 180° C. for 3 h. In sequence, the mixture was left to cool down to room temperature. A reddish-brown solution was obtained after filtering off the fibers (pulp). The solvent was removed at 60° C. using a rotoevaporator. After solvent removal, a brown oil (non-pyrolytic bio-oil) was obtained. In turn, the pulp was washed with acetone, and then dried under vacuum evaporation. From 6.2 g of sugarcane bagasse, 1.6 g of non-pyrolytic bio-oil and 4.4 g pulp were obtained (Table 1, entry 14).
The enzymatic saccharification was performed in a jacket reactor (150 mL) containing an 1 wt % (dry basis) suspension of the substrate dispersed in 0.1 mol L-1 acetate buffer (100 mL, pH 4.5). The mixture was stirred at 45° C. The reaction was initiated by adding Celluclast® into the suspension (0.5 mL, 350 U, aqueous solution, T. reesei, EC 3.2.1.4, Sigma). At defined times, aliquots of the reaction mixture were taken. The samples were immediately heated at 100° C. for 10 min to inactivate the enzymatic preparation. Next, they were centrifuged and filtered. The formation of glucose was determined by HPLC. Typically, the filtered sample was then analyzed on an HPLC (Perkin Elmer Series 200) equipped with a column Nucleogel Ion 300 OA (Macherey-Nagel). Analysis conditions: mobile phase: H2SO4 5 mM; flow: 0.5 mL/min; back-pressure: 62 bar; temperature: 80° C. The results are displayed in
The determination of humidity of the pulps and starting material was determined on a thermobalance (Ohaus MB25). Typically, the samples (2 to 3 g) were heated up to 105° C. for 10 min. The humidity was determined as the weight loss after 10 min.
For the determination of the ash content, ca. 100 mg of carbohydrate fraction or starting material were placed into a quartz crucible. The crucibles were then placed in an oven and heated up from room temperature to 450° C. in 1 h; 450° C. to 750° C. in 2 h; 750 ° C. for another additional 2 h. Henceforth, the crucibles were cooled to room temperature and weighted. The residue remained after the treatment was considered as the ash content. For each sample, this analysis was repeated four times.
The composition of the pulps and starting material in terms of glucans, xylans and elemental analysis followed the same procedure as for lignin analysis. Pulps and stating materials were milled with cryo-milling (CryoMill Retsch) with the following milling program: precooling 10 min, 5 s−1; milling 5 min, 20 s−1. The milled sample (50 mg) was then saccharified adding a sulfuric acid solution 72% v/v (0.5 mL) and stirring at 38° C. for 5 min. After this time, distillated water (10 mL) was added into the mixture and the saccharification performed at 130° C. for 1.5 h. The filtered solution was then analyzed on an HPLC (Perkin Elmer Series 200) equipped with a column Nucleogel Ion 300 OA
(Macherey-Nagel). Analysis conditions: mobile phase: H2504 5 mM; flow: 0.5 mL/min; back-pressure: 62 bar; temperature: 80° C. For the determination of the Klason lignin content, the above-mentioned saccharification procedure was performed on a ten-fold larger scale. After saccharification at 130° C. for 1.5 h, the residue (Klason lignin) was filtered through a membrane (1 μm, Millipore), the solid was washed with distilled water until a neutral pH. Finally, the solid was dried at 60° C. for 1-2 days. The weight of this dried solid was then considered as residual Klason lignin in the pulps or starting material. The results are summarized in Table 3.
The reaction mixtures were analyzed using 2D GC×GC-MS (1st column: Rxi-1 ms 30 m, 0.25 mm ID, df 0.25 μm; 2nd column: BPX50, 1 m, 0.15 mm ID, df 0.15 μm) in a GC-MS-FID 2010 Plus (Shimadzu) equipped with a ZX1 thermal modulation system (Zoex). The temperature program started with an isothermal step at 40° C. for 5 min. Next, the temperature was increased from 40 to 300° C. by 5.2° C. min−1. The program finished with an isothermal step at 300° C. for 5 min. The modulation applied for the comprehensive GC×GC analysis was a hot jet pulse (400 ms) every 9000 ms. The 2D chromatograms were processed with GC Image software (Zoex). The products were identified by a search of the MS spectrum with the MS library NIST 08, NIST 08s, and Wiley 9. The semi-quantification of the products was performed using the GC×GC-FID images. The semi-quantitative results are presented in Table 2.
Apparent molecular weight distribution of the organosolv lignin and non-pyrolytic bio-oils. In THF, about 2 to 10 mg of the sample was dissolved. The sample solutions were analyzed on an HPLC (Perkin Elmer Series 200) equipped with GPC columns (four combined columns, TSKgel Super HZ1000 (two), HZ2000, HZ3000 from Tosoh Bioscience). Analysis conditions: mobile phase: THF; flow: 0.4 mL/min; back-pressure: 71 bar; temperature 60° C. The analytes were detected by a diode array detector at 236 nm. The result are shown in
Crystallinity index of the pulps was determined by X-ray diffraction (as reported by S. Park et al. Biotechnology for Biofuels 2010, 3:10). The powder X-ray diffraction patterns of the samples were obtained with a STOE STADIP transmission diffractometer operated at 50 kV and 40 mA, using monochromatized Mo-Kα1 radiation and a position sensitive detector. The results are displayed in
| Number | Date | Country | Kind |
|---|---|---|---|
| 14150383.9 | Jan 2014 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2015/050101 | 1/6/2015 | WO | 00 |
