CATALYST COMPOSITION

TECHNICAL FIELD

The invention relates to converting of lignocellulosic material and more particularly to an effective and active catalyst composition for the conversion of lignocellulosic material, and to methods of making and using said catalyst composition. BACKGROUND

Lignin is one of the most abundant biopolymers in the nature and it is produced in large amounts in the paper industry. Global commercial yearly production of lignin is around 1.1 million metric tons and lignin is used in a wide range of low volume niche applications where typically the form but not the quality of lignin is important.

Lignin functions as a support through strengthening of wood (xylem cells). Lignin is an unusual biopolymer because of its heterogeneity and lack of defined primary structure. The building blocks of lignin are aromatic compounds and thus it is a valuable renewable source of aromatic compounds, useful for chemical and fuel production. The chemical structures of lignin and lignin precursors (coumaryl alcohol, coniferyl alcohol and sinapyl alcohol) are shown below.

In the conversion of lignin it may be subjected to depolymerization carried out in homogeneous or heterogeneous phases where the depolymerization may be performed in the presence of catalysts. After the depolymerization the obtained depolymerized product may be hydrotreated followed by separation of the product obtained from hydrotreatment into different fractions which may further be processed into hydrocarbons or other chemicals. Conversion of lignin may also be realized by hydrotreating without depolymerization. It is necessary to depolymerize lignin to smaller oligomers and monomers, which are suitable for further processing by hydrotreatment etc. Despite the ongoing research and development of processes and catalysts for the conversion of lignocellulosic materials, there is still a need to provide new catalyst compositions for improved conversion of lignocellulosic materials.

SUMMARY OF THE INVENTION

Disclosed herein is a catalyst composition comprising ruthenium (Ru) supported on zirconia (Zr02), where said zirconia comprises 60-100 wt% of monoclinic phase of zirconia .

Also disclosed herein is a method of preparing a catalyst composition comprising ruthenium supported on zirconia comprising 60-100 w% of monoclinic phase of zirconia, said method comprising the steps where

in the first step an aqueous solution of Ru precursor is mixed at a temperature from 5 to 85°C with zirconia comprising 60-100 wt% of monoclinic phase of zirconia to obtain a mixture,

in the second step the pH of the mixture is adjusted to 7.5 - 10 with an alkali and mixing is continued for 0.5 - 30 hours,

in the third step solid material is recovered from the mixture obtained in the second step, in the fourth step the solid material is dried at a temperature from 50 to 200°C and a catalyst composition comprising Ru supported on Zr02 comprising 60-100 wt% of monoclinic phase of zirconia is obtained.

Also disclosed herein is the use of a catalyst composition comprising ruthenium supported on zirconia, where said zirconia comprises 60-100 wt% of monoclinic phase of zirconia, in catalytic conversion of lignocellulosic material to aromatic compounds, linear and branched hydrocarbons and other chemicals. Characteristic features of said catalyst composition, the method of preparing a catalyst composition, and the use of the catalyst composition in catalytic conversion of lignocellulosic material are presented in the appended claims. DEFINITIONS

The term "catalytic conversion of lignocellulosic material" refers here to treating lignocellulosic material in the presence of at least one catalytic material to effect change in the structure of the lignocellulosic material, at least to reduce the molecular size and change the functionality.

The term "lignocellulosic material" refers here to lignin or derivatives thereof and combinations thereof. The lignin or derivatives thereof may be derived from any wood or plant based material, such as wood based raw material, woody biomass, lignin containing biomass such as agricultural residues, bagasse and corn stover, woody perennials, vascular plants, recycled brown board, deinking pulp and their combinations. The term also refers to lignin or derivatives thereof obtained from Kraft black liquor (Kraft lignin), alkaline pulping process, soda process, organosolv pulping and any combination thereof, such as lignosulfonates. The weight average molecular weight of lignin isolated from the above is Mw = 500-10 000 Da, and the number average molecular weight Mn= 700-2000 Da and polydispersity is 2-4.5. The degree of polymerization of this kind of lignin is 10-25. Lignin separated from pure biomass is sulphur-free and thus valuable in further processing.

The term "lignin" refers here to a class of complex organic polymers that form important structural materials in the support tissues of vascular plants and some algae. Chemically, lignin is a very irregular, randomly cross-linked polymer with a weight average molecular weight of 500 Daltons or higher. Said polymer is the result of an enzyme-mediated dehydrogenative polymerization of three phenyl propanoid monomer precursors, i.e. coniferyl, synapyl and coumaryl alcohols. Coniferyl alcohol is the dominant monomer in conifers (softwoods) . Deciduous (hardwood) species contain up to 40% syringyl alcohol units while grasses and agricultural crops may also contain coumaryl alcohol units.

The term "zirconia" refers to zirconium oxide with the chemical formula Zr02. The crystal structure of Zr02 exists in three polymorphic phases i.e. Zr02 has three different polymorphic forms: monoclinic, tetragonal and cubic. The cubic phase is formed at very high temperatures (>2370 °C), at intermediates temperatures (1150-2370 °C) the oxide has a tetragonal structure and from room temperature to 1150°C the material is stable as monoclinic structure. Each of these polymorphic phases differ structurally significantly from each other and they exhibit different acid/base properties and surface hydroxyl group concentrations. A phase diagram for Zr02 is shown in Figure 1 (www, materia ldesiqn.com/system/files/..JZrCh phase transitrion . pdfi . As can be realized from the figure, the three structures, cubic, tetragonal and monoclinic are different. The chemical bond is the same Zr-0 but how they are organized in the space is different.

The term "monoclinic phase of zirconia" or "monoclinic zirconia" or "monoclinic ZrC " refers here to a specific crystal structure of zirconia having characteristic X-ray diffraction patterns, i .e. 2Θ reflections at 24.3, 28.3, 31.5 and 34.5 in the X-ray diffractogram (Joint Committee on Powder Diffraction Standards Card Numbers (JCPDS), card no. 37- 1484) . The X-ray diffractogram of monoclinic phase of zirconia is shown in Figure 2.

The term "tetragonal phase of zirconia" or "tetragonal zirconia" or "tetragonal ZrC " refers here to specific crystal structure of zirconia having characteristic X-ray diffraction patterns, i .e. 2Θ reflections at 30.4 and 35.2 in the X-ray diffractog ram (JCPDS ca rd no. 17- 0923) . The X-ray diffractogram of tetragonal phase of zirconia is shown in Figure 2.

The term "single stage" method refers here to a method or process, which is carried out in one reaction vessel and where several chemical reactions happen successively in one vessel (reactor) . The advantage of this configuration is that the number of procedures and intermediate purification steps are reduced . Several catalytic reactions can be combined in the same reaction vessel . The term "depolymerization/hydrotreatment" or "depolymerization and hydrotreatment" "hydrotreatment" or "hydrotreating" refers to catalytic conversion of lignocellulosic materials in the presence of alkali . Depolymerization and hydrotreatment reactions, comprising a ny combinations of the reactions of depolymerization, hydrogenation, hydrodeoxygenation hydroisomerization, hydrodenitrification, hydrodesulfurization and hydrocracking, and coke reforming, coke/carbon/char gasification, WGS (water-gas-shift) reactions and Boudua rd reactions may ta ke place in the catalytic conversion of lignocellulosic materials.

The term "pretreatment" refers here to treatment of lignocellulosic materials in the presence of alkali, where at least partial depolymerization of lignocellulosic materials takes place. All weight percentages regarding the catalyst composition are calculated from the total weight of the catalyst composition.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 shows a phase diagram of Zr02.

Figure 2 illustrates X-ray diffraction patterns of monoclinic Zr02 and tetragonal Zr02. Figure 3 presents X-ray diffraction pattern of the synthesized catalyst Ru supported on monoclinic-Zr02 of example 2 and that of momoclinic-Zr02 only.

Figure 4 shows results of the single stage lignin depolymerization and hydrotreatment catalyzed by Ru supported materials.

Figure 5 presents GPC analysis of organic phase vs residual lignin fractions obtained from Kraft lignin in single stage method depolymerization and hydrotreatment catalyzed by Ru/ monoclinic Zr02, in example 5.

Figure 6 presents GPC analysis of organic phase vs residual lignin fractions obtained from Kraft lignin in single stage depolymerization and hydrotreatment catalyzed by Ru/ tetragonal Zr02, in example 5.

DETAILED DESCRIPTION

It should be understood that although an illustrative implementation of one or more embodiments are provided below, the disclosed compositions and methods can be implemented using any number of techniques. The disclosure should in no way be limited to the illustrative implementation, drawings, or techniques illustrated below, including the exemplary designs describe herein, but can be modified within the scope of the appended claims along with their full scope of equivalents.

Catalyst composition

It was surprisingly found that several advantageous effects may be achieved with a catalyst composition comprising ruthenium (Ru) supported on zirconia comprising 60-100 wt% of monoclinic phase of zirconia. Said catalyst composition is particularly useful as a catalyst for conversion of lignocellulosic materials to aromatic compounds, hydrocarbons and other chemicals. Further, it is an active catalyst for and it may be used in the depolymerization, hydrogenation, hydrodeoxygenation (HDO), hydoisomerization (HI), hydrodenitrification (HDN), hydrodesulfurization (HDS) and hydrocracking (HC) reactions, coke reforming, coke/carbon/char gasification, WGS (water-gas-shift) reactions and Bouduard reactions, also under mild conditions. In an embodiment the catalyst composition comprises ruthenium supported on zirconia, where said zirconia comprises 80-100 wt% of monoclinic phase of zirconia.

In an embodiment the zirconia comprises 85-100 wt% of monoclinic phase of zirconia.

In an embodiment the zirconia comprises 90-100 wt% of monoclinic phase of zirconia.

In another embodiment the zirconia comprises 95-100 wt% of monoclinic phase of zirconia.

In another embodiment the zirconia comprises 98-100 wt% of monoclinic phase of zirconia.

The remaining part of zirconia may exist as tetragonal phase or another crystal form.

In an embodiment the catalyst composition comprises 0.2 - 5 wt% of Ru. In another embodiment the catalyst composition comprises 0.3 - 3 wt% of Ru. In still another embodiment the catalyst composition comprises 0.5 - 2.5 wt% of Ru. In an embodiment the catalyst composition comprises metallic Ru particles having a small average particle size, in the range from 0.1 to 30 nm. In another embodiment the catalyst composition comprises metallic Ru particles having average particle size in the range from 0.5 to 20 nm. In still another embodiment the catalyst composition comprises metallic Ru particles having average particle size in the range from 1 to 15 nm. The particle size determination may suitably be carried out by methods based on SEM (Scanning Electron Microscope) or HR-TEM (High Resolution Transmission Electron Microscope).

In an embodiment in the catalyst composition the Ru metallic particles are highly dispersed onto the support. In an embodiment the metal dispersion of Ru, measured by CO chemisorption method, is in the range from 15 to 45 %, where the specific surface area (BET) of zirconia is not more than 100 m ² /g and the Ru loading is not more than 2 wt%

In another embodiment the catalyst composition may additionally comprise at least one dopant selected from Pd, Pt, Vn, Ni, Sn, La, Ga, Co and combinations thereof. The amount of the dopant in the catalyst composition is not more than 2 wt%. The total amount of Ru and the dopant is not more than 5 wt%. ΖΓΟ2 comprising 60-100 wt% of monoclinic phase of zirconia interacts strongly with the active phase (Ru), it inhibits sintering of supported oxides in the presence of water and high temperatures, it possesses high thermal stability and good chemical stability, and it is more inert than the classical supported oxides. Further, Zr02 comprising 60-100 wt% of monoclinic phase of zirconia possesses acidity, basicity as well as reducing and oxidizing ability.

In an embodiment the catalyst composition comprises Zr02 comprising 60-100 wt% of monoclinic phase of zirconia as the only support.

In another embodiment the catalyst composition may comprise as an additional support an oxide selected from Ce02, T1O2, MgO, ZnO, S1O2 AI2O3 and combinations thereof. Examples of suitable support combinations are Zr02-Si02, ZrC -AkOs, Zr02-Ti02, Zr02- ZnO, Zr02-Ce02 and Zr02-MgO, where Zr02 refers to Zr02 comprising 60-100 wt% of monoclinic phase of zirconia.

In an embodiment the support may comprise Zr02 comprising 60-100 wt% of monoclinic phase of zirconia and less than 50 wt% of an additional support. In another embodiment the support may comprise the Zr02 comprising 60-100 wt% of monoclinic phase of zirconia and less than 40 wt% of the additional support, suitably less than 30 wt% of the additional support, and even more suitably less than 20 wt% of the additional support. In still another embodiment the support may comprise Zr02 comprising 60-100 wt% of monoclinic phase of zirconia and less than 10 wt% of the additional support, suitably less than 5 wt% of the additional support, and even more suitably less than 2 wt% of the additional support. Method of preparing a catalyst composition

Disclosed herein is also a method of preparing a catalyst composition comprising Ru supported on Zr02 comprising 60-100 w% of monoclinic phase of zirconia . The method can be defined as a co-precipitation method. Particularly disclosed herein is a method of preparing a catalyst composition comprising Ru supported on Zr02 comprising 60-100 w% of monoclinic phase of zirconia, said method comprising the steps, where in the first step an aqueous solution of Ru precursor is mixed with Zr02 comprising 60- 100 wt% of monoclinic phase of zirconia, at a temperature from 5 to 85 °C to obtain a mixture, in the second step the pH of the mixture is adjusted to 7.5 - 10 with an alkali and mixing is continued for 0.5 to 30 hours,

in the third step solid material is recovered from the mixture obtained in the second step, in the fourth step the solid material is dried at a temperature from 50 to 200°C and a catalyst composition comprising Ru supported on Zr02 comprising 60- 100 w% of monoclinic phase of zirconia is obtained . Incorporation of Ru onto Zr02 comprising 60- 100 w% of monoclinic phase of zirconia may be performed by means of the above described co-precipitation method .

In an embodiment the Ru precursor is selected from sa lts and organometallic complexes of Ru . In an embodiment the Ru precursor is selected from [Ru3(CO)i2], Ru(NH3)4Cl2, [((Cy)RuCI ₂ ) ₂ ], [((Cp)Ru(PPh ₃ ) ₂ CI)], [((pMeCp)RuCI2)2], RuCI ₃ -3H ₂ 0 and Ru(N0 ₃ ) ₂ . In a suitable embodiment the Ru precursor is selected from [Ru3(CO)i2], Ru(NH3)4Cl2, RuCl3-3H ₂ 0 and Ru(N0 ₃ ) ₂ .

Typically, an aqueous solution of the Ru precursor is prepa red to attain 0.2 - 5 wt% of Ru in the final solid . In an embodiment the concentration of the Ru precursor in the aqueous solution is 0.01- 1 wt%.

In an embodiment RuCl3-3H20 is used as Ru precursor and 0.0065 - 0.1424 grams of this precursor are diluted in an aqueous solution (20 - 30 ml) to attain 0.2 - 5.0 wt% of Ru in the final solid . In an embodiment the aqueous solution of the Ru precursor is mixed with 1 gram of the Zr02 comprising 60- 100 w% of monoclinic phase of zirconia

In an embodiment the mixing in the first step is carried at a temperature from 5°C to 85°C. In an embodiment the mixing in the first step is carried at a temperature from 15°C to 70°C. In an embodiment the mixing in the first step is carried at a temperature preferably from 20°C to 50°C.

In an embodiment the Zr02 comprising 60- 100 w% of monoclinic phase of zircona is pretreated at the temperature of 150-300°C, suitably in air, to eliminate humidity and other organic impurities from the solid .

In an embodiment, the mixture is stirred in the first step for 10 min to 10 hours. In an embodiment, in the second step the alkali is selected from alkali metal hydroxides and alkaline earth metal hydroxides, preferably KOH or NaOH is sued. Preferably an aqueous solution of NaOH is used, said NaOH having concentration ranging from 0.1 M to 2.0 M.

In an embodiment in the second step the mixture is stirred at the temperature from 5 to 35°C. In an embodiment the mixture is stirred for 0.5-30 hours, suitably from 1 to 24 hours. In an embodiment in the third step the solid material is recovered by filtration, centrifuging, spray drying or the like. The solid material is suitably washed with water until pH is in the range of 6.5 - 7.5.

In an embodiment in the fourth step the solid material is dried (under air, atmospheric pressure) at 50-200°C. Suitably the drying temperature is 60 - 140°C.

The Ru content in the thus obtained catalyst composition may be determined by ICP (inductively coupled plasma mass spectrometry) measurements. In an embodiment the dried final solid material (the catalyst composition) is thermally activated (reduced) at 80-350°C, suitably under H2, in situ or separately, prior to its use in catalytic processing. In another embodiment the dried solid material is thermally activated at 100-300°C, preferably at 200-300°C. The Zr02 comprising 60-100 w% of monoclinic phase of zirconia may be obtained using hydrothermal synthesis methods known in the art. Alternatively it may also be obtained by converting Zr02 comprising a mixture of monoclinic phase and tetragonal phase, or only tetragonal phase, to the Zr02 comprising 60-100 wt% of monoclinic phase. Use of the catalyst composition

The conversion of lignocellulosic materials, such as lignin, to produce depolymerized molecules for chemical applications may be carried out in different ways. In one alternative the lignocellulosic material is subjected to depolymerization and hydrotreatment. The depolymerization and hydrotreatment may be done separately in two steps. In the first step, the lignocellulosic material is at least partly depolymerized and in the second step, it can be hydrotreated, followed by separation into different fractions that can be processed separately into chemicals or hydrocarbons in the gasoline or diesel pool. In another alternative, depolymerization and hydrotreatment can be done in one step "single stage" approach, this approach being very interesting from a commercial process viewpoint. In both cases, the process can be performed with our without pretreatment of the lignocellulosic materials. The use of the pretreatment may decrease cracking in the hydrotreatment step, whereby less gases comprising light hydrocarbons are formed in the product.

It was surprisingly found that the catalyst composition comprising Ru supported on Zr02 comprising 60-100 wt% of monoclinic phase of zirconia is very efficient in conversion of lignocellulosic materials to aromatic compounds and other hydrocarbonaceous components, such as linear and branched hydrocarbons and chemicals.

The catalyst composition was found particularly efficient in lignin depolymerization in at least two steps comprising a first step of pretreatment/depolymerization and in a second step comprising hydrotreatment, as well as in single stage simultaneous pretreatment/depolymerization and hydrotreatment processes. The catalyst comprising Ru supported on Zr02 comprising 60-100 w% of monoclinic phase of zirconia was more active in the conversion of lignin than the catalyst containing tetragonal Zr02 and the catalyst containing the mixture of monoclinic and tetragonal Zr02.

The catalyst composition comprising Ru supported on Zr02 comprising 60-100 wt% of monoclinic phase of zirconia may be used in processing of lignocellulosic materials to effect one or more of the following depolymerization, hydrogenation, hydrodeoxygenation, hydroisomerization hydrodenitrification, hydrodesulfurization, hydrocracking, coke reforming, coke/carbon/char gasification, WGS (water-gas-shift) reactions and Bouduard reactions.

The catalyst composition comprising Ru supported on Zr02 comprising 60-100 w% of monoclinic phase of zirconia may be used in the hydrotreatment and also in the depolymerization of the lignocellulosic material.

The catalyst composition comprising Ru supported on Zr02 comprising 60-100 w% of monoclinic phase of zirconia gives higher organic yields and better quality products, when compared with prior art catalysts and catalyst compositions containing tetragonal zirconia. The loading of Ru in the present catalyst composition may be approx. 2 wt% or even less, which is lower than that in commercial Ru/C catalysts typically containing 5 wt% of Ru. The catalyst composition is more stable and resistant at conversion reaction conditions and performs better when compared with prior art catalysts and catalyst compositions containing tetragonal zirconia; further it is more tolerant than commercial sulfided hydrotreatment catalysts under the harsh conditions.

The catalyst composition allows also performing the lignin depolymerization and hydrotreatment in single stage (in one step) directly providing a liquid hydrocarbon mixture with reduced oxygen content. Said liquid hydrocarbon mixture may be further processed to fuels and chemicals for industrial processes and for other uses.

The high activity of Ru in several reactions allows the utilization of the catalyst composition at wide range of operation conditions. This is beneficial in the processing of biomass as highly reactive compounds are formed. As the catalyst composition is active also at mild reaction conditions, more particularly at moderate temperatures, whereby highly reactive compounds that would be converted to char at high temperatures are now converted into valuable products.

The catalyst composition can be used with different types of lignocellulosic materials, such as lignin or derivatives thereof, Kraft lignin, native lignin, lignosulfonates, lignin obtained from bio-refinery processes, such as enzymatic, alkaline or acid hydrolysis or steam explosion, and any combinations thereof.

Higher organic yields, less residual lignin and less gases are obtained when compared with prior art catalysts and catalyst compositions containing tetragonal zirconia, in converting lignin, and further, the oxygen content of the products is lower.

The properties of the catalyst composition may be modified further with dopants and additional supports, providing further improvements to resistance to temperature and pressure during reactions allowing maintaining the stability of the catalysts even after several reuses.

Examples

The following examples are illustrative embodiments of the present invention, as described above, and they are not meant to limit the invention in any way. The invention is illustrated also with reference to the figures. Example 1

Synthesis of Ζ1Ό2 comprising monoclinic phase of zirconia

The starting materials used for the synthesis were zirconyl nitrate hydrate (ZrO(N03)2.xH20) and sodium hydroxide (NaOH). All the chemicals were used without further purification. A mass of ZrO(N03)2-xH20 and an amount of NaOH were dissolved each one in a volume of distilled water, to form 0.5 M and 5 M solutions, respectively. The NaOH solution was slowly added (0.50 ml_ min ^_1 ) to the ZrO(N03)2-xH20 solution under constant stirring (300 rpm). Then, the mixture was placed under ultrasound for about 30 min to obtain proper mixing of the two solutions. Further, the above solution was loaded into a Teflon-lined autoclave, and then absolute ethanol was added (buffering agent). Finally, the autoclave was sealed and maintained at 200°C for 24 hours, after this period the autoclave was allowed to cool down to room temperature. The formed precipitate was filtered off, and washed with a solution of absolute ethanol and distilled water several times, and then dried in air at 100°C for 2 hours. After that, the white powder was characterized by XRD. (Zr02 pure monoclinic phase)

Example 2

Preparation of Ru supported on Monoclinic Zr02

Monoclinic Zr02 (comprising more than 90 wt% of the monoclinic phase of zirconia) was employed as support for catalysts preparation. Incorporation of Ru onto the Zr02 support was performed by means of co-precipitation method using RuCh-3H20 as metal precursor. An aqueous solution (20 ml) containing 0.052 g of the Ru precursor was prepared to attain 2 wt% of Ru in the final solid. This solution was mixed with 1 gram of the Zr02 support (previously treated at 250°C in air to eliminate humidity and other organic impurities from the solid), the mixture was stirred for 30 minutes. After that an aqueous solution of NaOH (0.5M) was added to adjust the pH of the mixture in the range pH = 8-9, and then the mixture was continuously stirred at 1000 rpm and room temperature for 12 hours. Then, solid was recovered by filtration and washed with water until pH = 7 was reached, also confirming that washing liquid was completely free of chlorine species. The solid was dried under air atmosphere in oven at 100°C temperature for 12 hours. The Ru content in the thus obtained material (final solid) was determined by ICP and XRF (X-ray fluorescence) measurements (1.4 wt% in Ru/Zr02 comprising monoclinic phase of zirconia). The solid was thermally activated (reduced) at 250°C under continuous flow of H2 (100 ml/min) during 3 hours followed by gradual cooling under continuous flow of N2 (25 ml/min), before it was used in the catalytic tests. In addition, XRD (X-ray diffraction) measurements after thermal activation procedure were performed to determine the structure of the Zr02 support, this meaning confirming the presence of monoclinic phase of zirconia . Figure 3 presents the X-ray diffraction pattern of the prepared Ru/monoclinic Zr02 catalyst and that of monoclinic Zr02 support only. The graph shows that the monoclinic Zr02 remains unaltered in the Ru/monoclinic Zr02 catalyst. Catalyst composition (1.6 wt% in Ru/tetragonal ZrC ) was made using tetragonal zirconia (comprising more than 90 wt% of the tetragonal phase of zirconia) in a similar way.

Exarsipte 3

Catalytic hydrotreating of model feed

The obtained catalyst composition comprising Ru supported on monoclinic Zr02 (Zr02 comprising more than 90 wt% of monoclinic phase of zirconia) was used as catalyst for hydrotreating a model feed . The model feed comprised 6 selected phenolic compounds, i.e. guaiacol, ethyl-guaiacol, syringol, syringone, acetosyringone and acetovanillone, which were selected to simulate depolymerized lignin. Three different Ru supported catalysts were tested as catalysts for this hydrotreatment step carried out under mild conditions and using the model feed as feedstock. The model feed was diluted in EtOH (1) / water (2) mixture (Composition of the diluted model feed is presented in Table 1). The diluted model feed was treated with the heterogeneous Ru catalyst under H2 atmosphere (initial pressure 22 bar) and at 250 °C as a slurry. Hydrotreatment results attained with Ru/monoclinic Zr02, and as comparative catalyst compositions Ru/C and Ru/tetragonal Zr02 catalytic materials are summarized in Table 2.

Table 1 : Composition of Model Feed diluted with ethanol/water.

Composition of the Model Amount

Feed

grams wt%

Water 98.08 65.28 99.79

Ethanol 49.04 32.64

Guaiacol 0.58 0.38

4-Ethyl-guaiacol 0.57 0.38

Syringol 0.57 0.38 0.21

Vanillin 0.39 0.26

Acetovanillone 0.58 0.39

Acetosyringone 0.42 0.28

Total in sample 150.25 100.00 Ta ble 2 : Evaluation of the catalytic activity of Ru/monoclinicZrC , Ru/C and Ru/tetragonalZr02 catalytic materials in the hydrotreatment of the model feed (in slurry)

TON = Turn over number (mole of product/ mole of catalyst)

Reactions Conditions : 10 g of model feed, 0.05 g of catalyst, in autoclave batch reactor ( 15 ml) at 250°C and 25 bar of H2 initial pressure.

The conversion achieved with the commercial catalyst is attributed to its high loading of Ru, the loading was more than 3 times higher than for the Zr02 supported catalysts. Even though the metal content was lower in the Zr02 supported catalysts, in particular with the monoclinic Zr02, the conversion was not significantly different. Having a low metal loading makes the catalyst composition more attractive because less of valuable Ru is needed . Furthermore, more of highly desired hydrocarbon compounds were produced with the catalyst having the monoclinic Zr02 as support.

Based on the results presented above, the catalyst using tetragonal Zr02 as support is the least suitable due to the low conversions achieved and the low amounts of hydrocarbons produced . Example 4.

Lignin processing via pretreatment/depolymerization and hydrotreatment

The Ru supported on monoclinic Zr02 (comprising more than 90 w% of monoclinic phase of zirconia) was used as catalyst for processing lignin in a two-step process comprising a first step where lignin was pretreated/depolymerized with a homogenous catalyst, that is, NaOH, and a second step, where hydrotreatment under mild conditions was ca rried out. In this approach, the conversion of lignin to hydrocarbons can be done without the need of using a high temperature and high pressure in the pretreatment/depolymerization step. Thus, after the treatment of lignin with an aqueous solution comprising NaOH and EtOH/water at 70°C, the alkali treated reaction mixture comprising the alkali and EtOH/water was hydrotreated in a slurry reactor under H2 atmosphere (initial pressure 22 bar) and at 250°C in the presence of a metal supported catalyst. Results of evaluation of the catalytic activity obtained for the catalysts comprising Ru supported on monoclinic Zr02, and commercial Ru/C and Ni supported on monoclinic Zr02 as comparative catalyst are summarized in Table 3.

To only have one pretreatment/depolymerization step at low temperatures (70°C) and atmospheric pressure makes this process suitable for the large scale application as it is less expensive and complicated than those of prior art using high temperature and pressures for the depolymerization step. In addition, the pretreatment/depolymerization with alkali may also be carried out using only aqueous alkali, avoiding the use of EtOH.

Table 3 : Evaluation of the catalytic activity of Ru and Ni supported materials in the two step processing of lignin

Pretreatment/Depolymerization and Hydrotreatment

Pretreatment/Depolymerization 70/atmospheric 70/atmospheric 70/atmospheric

T (°C)/P(bar)

Catalyst NaOH NaOH NaOH

Hydrotreatment T(°C)/P(bar) 250/<50 250/<50 250/<50

Catalyst 5% Ru/C 1.9% Ru/Zr0 ₂ 10% Ni/Zr0 ₂

EtOH/water ratio 1/3 1/3 1/3

Yields:

Organic (%) 73.50 79.73 29.28

Gas (%) 20.81 14.91 10.36

Residual lignin (%) 11.26 10.70 55.38

Total identified prod. (%) 20.10 11.80 4.46

Organic product

composition:

Oligomeric compounds (%) 79.90 88.20 95.54

Alcohols (%) 10.16 3.35 1.39

Other lights (%) 4.26 1.09 0.94

Aromatics (%) 5.02 6.64 2.12 These examples show several advantages achieved with the catalyst composition comprising Ru/monoclinic Zr02 comprising 60-100 wt% of monoclinic phase of zirconia, which are listed in the following :

The organic yields achieved with Ru/monoclinic Zr02 comprising 60- 100 wt% of monoclinic phase of zirconia catalyst are higher than with the other catalysts that contain even higher metal loadings

The residual lignin (non-converted lignin) is low

More aromatics a re produced with the monoclinic Zr02 supported Ru catalyst than with any other catalyst. These compounds can be converted further in downstream processes. Products containing large amounts or aromatics can be used for example as dropping components in jet fuel .

Monoclinic Zr02 was also used in the preparation of the Ni catalyst, but this catalyst was not suitable for this application as the yield of organic phase produced was lowest and more than 55 wt-% of lignin remain unreacted .

- Based on the results presented above, best results are achieved with the combination of Ru on monoclinic Zr02.

Further, the a mount of oligomeric compounds indicates that there a re compounds that have high boiling points and thus they can't be identified by gas chromatography (GC) but they could be hydrotreated in downstream processes.

Example 5

Lignin Depolymerization and Hydrotreatment

Ru supported on monoclinic Zr02 comprising more than 90 w% of the monoclinic phase of zirconia was used as the catalyst for processing the lignin to produce hydrocarbons. In this example depolymerization and hyrotreatment are done in single stage. Kraft lignin was pretreated at 70°C/atmospheric pressure, using an aqueous alkali solution comprising NaOH and EtOH/water ( 1/3 mass ratio ethanol to water) to obtain a pretreated mixture. The pretreated mixture comprising the alkali (acting as homogeneous catalyst) and EtOH/water was hydrotreated with the Ru supported on monoclinic Zr02 as heterogeneous catalyst. The depolymerization and hydrotreatment took place under H2 atmosphere (initial pressure^ 22 bar) and at 250°C. Results attained with Ru/Zr02 (monoclinic), a nd with Ru/Zr02 (tetragonal) and 5 wt% Ru/C (commercial) materials as compa rative catalysts for this process are summa rized in Figure 4 and Ta ble 4, respectively.

In Figure 4 organic phase yields, residual lignin yields, gas phase yields and coke yields, obta ined by means of GPC (gel permeation chromatography) analysis of the final product (organic fraction) and residual lignin are presented of the "single stage" lignin depolymerization and hydrotreatment using Ru/ZrC (monoclinic), Ru/ZrC (tetragonal), and Ru/C (S-A) materials as catalysts.

Additionally, the results obtained by means of GPC (gel permeation chromatography) analysis of the final product (organic fraction) and residual lignin for Ru/ZrC (monoclinic) and Ru/Zr02 (tetragonal) materials are also given in Figures 5 and 6.

Table 4 : Evaluation of the catalytic activity of Ru supported materials in lignin depolymerization and hydrotreatment.

Depolymerization and hydrotreatment

Pretreatment 70/atmospheric/ 70/atmospheric/ 70/atmospheric/

T (°C)/P(bar)/catalyst NaOH NaOH NaOH

Hydrotreatment Conditions 250/<50 250/<50 250/<50

T(°C)/P(bar)

Catalyst 5% Ru/C 1.9% Ru/Zr0 ₂ 1.5% Ru/Zr0 ₂

(commercial) (monoclinic) (tetragonal)

EtOH/water ratio 1/3 1/3 1/3

Yields:

Organic (%) 66.51 69.04 58.31

Gas (%) 5.67 5.04 6.01

Residual lignin (%) 19.65 24.52 31.90

Total identified products 22.00 15.00 14.73

(%)

Organic product

composition:

Oligomeric products (%) 78.00 85.00 85.27

Alcohols (%) 9.54 2.56 1.56

Other lights (%) 1.07 0.79 0.59

Aromatics (%) 8.31 8.57 8.31

Oxygen content of the 23.8 26.7 28.0

organic phase (%)

The catalyst containing Ru supported on monoclinic Zr02 yielded higher organic phase. The catalyst containing tetragonal Zr02 was significantly less active than the one containing monoclinic Zr02 or commercial 5% Ru/C catalyst. Larger amounts of aromatics are produced with the Ru/monoclinic Zr02 catalyst than with the other ones. Molecular weight distribution of organic phase and residual lignin fractions, after the process of example 5, were determined by liquid chromatography gel permeation (GPC) technique. Analyses were carried out on a Shimadzu Nexera XR liquid chromatograph equipped with two detectors: UV-visible (PDA) and refractive index (RI), using an Agilent Technologies PLgel 5 μιη MIXED-D (300 x 7.5 mm) packed column, and polystyrene commercial samples for molecular weight calibration. Tetrahydrofuran was used as mobile phase at a flow rate of 1.0 ml/min (Total analysis time = 15 min). Samples (3-5 mg) were dissolved in 1.0 ml of THF, and filtered with a syringe filter (0.45 μιη PTFE). GPC analysis of organic phase vs residual lignin fractions obtained from Kraft lignin depolymerization + hydrotreatment in "single stage" catalyzed by Ru/Zr02 monoclinic catalyst is presented in Figure 5 and by Ru/ZrC tetragonal catalyst is presented in Figure 6.

Example 6.

Single stage depolymerisation and hydrotreatment of lignin

Lignin was mixed in a reactor with an aqueous alkali solution containing homogeneous depolymerisation catalyst (NaOH), water and ethanol, and with a heterogeneous catalyst (Ru/C (commercial) or Ru/monoclinic Zr02 comprising 90 wt% of monoclinic phase of zirconia). H2 was introduced into the reactor at room temperature and then the temperature was increased to 250°C. At this temperature the reaction pressure was 50 bar. The conditions were maintained for 6 h before the reactor was cooled down and opened. The results obtained (compositions of the hydrotreated and depolymerized effluents) are presented in the Table 5 below. Table 5 : Compositions of the hydrotreated and depolymerized effluents

Composition of EtOH + water 1 : 3 / NaOH EtOH + water 1 : 3 / NaOH hydrotreated Depolymerization and Depolymerization and effluent (%) hydrotreatment: 5% Ru/C hydrotreatment: 2%

250°C, H ₂ = 50 bar Ru/monoclinic Zr02, 250°C,

H ₂ = 50 bar

Organic phase 56.51 70.44

Gas 12.66 15.95

Residual lignin 16.89 10

Tar 13.68 3.45

Ethylacetate 1.83 1.08

Alcohols 10.24 3.2

Ethers 0.15 0,09 Esters 0 0

Hydrocarbon C7 0.23 0.05

Phenol 0.14 0.04

Guaiacol 1.72 2.53

4-methylguaiacol 0.05 0.03

4-ethylguaiacol 0.59 0.31

Trimethoxy benzene 0.46 0.27

Syringol 0.26 0.17

vanillin 0.42 0.37

Iso-eugenol 0.07 0.07

Acetovanillone 0.54 0.56

Syringaldehyde 0 0

Acetosyringone 0.05 0.04

Oligomers 83.2 91.2

Oxygen content of 24.2 28.3

the organic phase

(%)

Processing the lignin a single stage using catalyst composition comprising Ru supported on monoclinic Zr02 yields a larger organic phase than when the commercial catalyst is used. Furthermore, with the catalyst composition comprising Ru supported on monoclinic Zr02 the amounts of tar and residual lignin formed were significantly lower than with the other catalyst. Thus the catalyst composition comprising Ru supported on monoclinic Zr02 converts the lignin into oligomers. These molecules can be process further, for example in hydrotreatment and hydrocracking to chemicals and drop in fuels.