Method for synthesis of tetrahydrofuran

Abstract

The disclosure relates to a method for synthesis of tetrahydrofuran (THF) from furfural, wherein furfural is reacted in solvent in the presence of Palladium (Pd) catalyst on a support at a temperature between 200 °C and 270 °C under a first atmosphere to obtain furan; the first atmosphere is removed, and hydrogen is added; and the furan is reacted under a second atmosphere with hydrogen and in the presence of the catalyst to obtain THF. The catalyst is the same during both decarbonylation of furfural to furan and hydrogenation of furan to THF.

Description

[0001] METHOD FOR. SYNTHESIS OF TETRAHYDROFURAN

[0002] FIELD OF THE DISCLOSURE

[0003] The present disclosure relates to a direct conversion of furfural to tetra hydrofuran (THF) in the presence of a solvent and a catalyst which is Palladium (Pd) on a support. Particularly furfural is reacted in a solvent, in the presence of a catalyst at a temperature between 200 °C and 270 °C under a first atmosphere to obtain furan; the first atmosphere is removed, and hydrogen is added; and the furan is reacted under a second atmosphere with hydrogen in the presence of the catalyst to obtain THF.

[0004] BACKGROUND OF THE DISCLOSURE

[0005] Furfural is a valuable platform chemical that is predominately obtained from biomass streams that are rich in pentoses, namely xylose. Purified furfural is serving as a precursor to various industrial chemicals, and it can for example be converted to value-added chemicals such as furan and tetrahydrofuran.

[0006] One of the significant conversions of furfural is its transformation into furan. This process typically involves catalytic decarbonylation, where furfural is heated in the presence of a catalyst. The resulting furan is a key building block in organic synthesis, used in the production of pharmaceuticals, agrochemicals, and fine chemicals.

[0007] Further hydrogenation of furan leads to the formation of tetra hydrofuran (THF). This process usually requires a hydrogenation catalyst and takes place under elevated hydrogen pressure. Traditionally, the conversion of furfural to furan is done in two steps in order to avoid catalyst poisoning during the hydrogenation. Tetra hydrofuran is highly desirable globally as a solvent, and it is produced on the scale of hundreds of thousands of tonnes per year. THF is widely used as a solvent and in the polymer industry, particularly as a monomer for polytetramethylene ether glycol (PTMEG), a precursor to spandex fibers. Until recently, tetrahydrofuran has been exclusively produced from fossil feedstocks such as n-butane and 1,4-butanediol which has become increasingly costly over the years. Thus, the production of THF from renewable resources, such as pentose sugars originating from biomass, is becoming economically feasible and interesting.

[0008] Furfural is a key renewable chemical that can be converted into valuable products like furan and THF through catalytic processes. These transformations not only enhance the economic value of furfural but also contribute to the development of sustainable and green chemical processes. By optimizing the processes, researchers and industries aim to reduce dependence on fossil resources, enhance the economic viability and support the transition to a more sustainable chemical industry.

[0009] Despite the ongoing research and development of synthesis of THF from furfural, there is still a need to overcome challenges associated with improving selectivity and yield and commercialization of the process.

[0010] BRIEF DESCRIPTION OF THE DISCLOSURE

[0011] An object of the present disclosure is to provide a simplified method for synthesis of tetra hydrofuran (THF) from furfural utilizing the same catalyst for decarbonylation and hydrogenation.

[0012] Traditionally the uninterrupted process of furfural conversion to THF is recognized to suffer from catalyst deactivation due to carbon monoxide (CO) poisoning, which is released in the first step of furfural decarbonylation. Thus, the entire process quickly becomes unfavourable when having to consider separation and / or purification steps in between the reactions.

[0013] The object of the disclosure is achieved by the method which is characterized by what is stated in the independent claims. Some embodiments of the disclosure are disclosed in the dependent claims.

[0014] The disclosure is based on the idea of providing a direct conversion of furfural to THF by a process utilizing the same catalyst during the whole process without poisoning of the Pd containing catalyst during the hydrogenation. In the method of the disclosure furfural is mixed in a solvent, such as THF or a derivative thereof, in the presence of a Palladium (Pd) catalyst on a support, at a temperature between 200 °C and 270 °C under a first atmosphere typically in liquid phase, whereafter the first atmosphere is removed, and hydrogen is added.

[0015] An advantage of the method of the disclosure is that no purification and / or no isolation, for example of an intermediate product, for example by distillation or by filtration is conducted before hydrogenation of furan to THF. Optionally, both the decarbonylation of furfural to furan and the hydrogenation of furan to THF reactions are conducted in a one-pot system, typically in one reactor. Alternatively, the decarbonylation and hydrogenation reactions are conducted as a continuous process.

[0016] An advantage of the disclosure is that no change of catalyst or adding of new catalyst is needed before furan undergoes hydrogenation and still the yields are good and the lifetime of the Pd containing catalysts is improved by minimising catalyst poisoning.

[0017] BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In the following the disclosure will be described in greater detail by means of preferred embodiments with reference to the accompanying drawings, in which:

[0019] Figure 1 shows furfural conversion and furan yield using the 5 wt-% Pd / ALOs catalyst while varying reaction temperature with 10 bars of nitrogen for 3 hours;

[0020] Figure 2 shows one-pot conversion of furfural to THF using a) 5 wt-% Pd / ALOs or b) 5 wt-% Pd / C at different reaction temperatures;

[0021] Figure 3 shows one-pot conversion of furfural to THF using 2-methyl-THF as solvent and a) 5 wt-% Pd / AI2O3 or b) 5 wt-% Pd / C at different reaction temperatures;

[0022] Figure 4 shows furfural conversion and furan yield with differing starting amounts of furfural using 5 wt-% Pd / AI2O3 catalyst at 240°C for 3 hours;

[0023] Figure 5a shows furfural conversion and furan yield with different Pd loadings (100 mg catalyst); Figure 5b shows furfural conversion and furan yield with different Pd loadings (200 mg catalyst); and

[0024] Figure 6 shows furfural conversion and furan yield using various catalysts at 210 °C, 10 bars of nitrogen for 3 hours.

[0025] DETAILED DESCRIPTION OF THE DISCLOSURE

[0026] The disclosure relates to a method for synthesis of tetra hydrofuran (THF) from furfural, wherein furfural is reacted in the presence of a solvent and in the presence of a catalyst at a temperature between 200 °C and 270 °C under a first atmosphere to obtain furan; the first atmosphere is removed, and hydrogen is added; and the furan is reacted under a second atmosphere with hydrogen in the presence of the catalyst to obtain THF; wherein the catalyst is Palladium (Pd) on a support. The catalyst is the same during both decarbonylation of furfural to furan and hydrogenation of furan to THF and typically no new catalyst is added between the decarbonylation and the hydrogenation. The solvent typically comprises THF or a derivative thereof.

[0027] In the embodiments of the disclosure the amount of furfural is typically 1 - 15 wt-% based on the total weight of furfural and solvent, w / w %. Preferably the amount of furfural is 1 - 13 wt-% and more preferably the amount is 2 - 3 wt- % based on the total weight of furfural and solvent, w / w %.

[0028] In the embodiments of the disclosure the solvent typically comprises one or more of THF or a derivative thereof, preferably THF or an alkylated derivative of THF, more preferably THF or a methylated derivative thereof. Optionally, the solvent comprises THF, 2-methyl-THF, 2,5-dimethyl-THF, 2,2,5,5-tetramethyl- tetra hydrofuran, tetra hydrofurfuryl alcohol, furfuryl alcohol or mixtures thereof.

[0029] In some embodiments of the disclosure the solvent is typically tetra hydrofuran (THF), a derivative thereof, or a mixture of any of these, preferably THF or an alkylated derivative of THF, more preferably the solvent is THF, a methylated derivative thereof or a mixture of any of these. Optionally, the solvent is chosen from any of THF, 2-methyl-THF, 2,5-dimethyl-THF, 2,2,5,5-tetramethyl- tetra hydrofuran, tetra hydrofurfuryl alcohol, furfuryl alcohol, or mixtures thereof.

[0030] A benefit of using THF as solvent is that the product THF does not need to be purified. Further, especially 2-methyl-THF and tetra hydrofurfury I alcohol are available from biobased feedstocks and green solvents. Thereto the boiling point and heat capacity of 2-methyl-THF is lower than that of water (100°C vs. 78°C) so less energy is required to separate it from the product THF.

[0031] The conversion of furfural to THF according to the invention consists of two chemical steps: Decarbonylation to furan and subsequent hydrogenation to tetra hydrofuran THF. To choose an optimal solvent for these to reaction the solvent needs to support these two distinct reactions but also offer some practical and operational benefits such as easy separation.

[0032] During the decarbonylation step the key rate-determining step is generally oxidative addition of the C(=O)-H bond to a Pd(0) surface to form an acyl-Pd intermediate, followed by decarbonylation and reductive elimination. This oxidative addition is typically preceded by p-(CO) or o-aldehyde coordination, which relies on an accessible carbonyl n-system.

[0033] Water is detrimental to the decarbonylation step in two ways. When dissolved in water, aldehydes are always in equilibrium with their geminal diol form. Although this is typically in the lower percentage, this diminishes the apparent presence of the carbonyl species and as such slows down decarbonylation. Additionally, as carbonylation takes place at high temperatures above 200 °C, the temperature influences the autohydrolysis of water causing it to have a pH of about pH 5 (pKw at 250°C=11.20). The acidic conditions caused by water at high temperature trigger decomposition of furfural liberating organic acids and the organic acids accelerate the process even further. It has been shown that up to about 30% of furfural in an aqueous solution degrade in ca. 13 min at 250°C.

[0034] Thereto secondary alcohols such as isopropanol in combination with palladium can cause transfer hydrogenations where the carbonyl group in furfural might be hydrogenated to an alcohol and as such is not anymore available for decarbonylation reactions.

[0035] Solvents comprising THF or 2-methyl-THF are therefore ideal solvents for the decarbonylation step as they do not engage as hydrogen donor in transferhydrogenation or contribute to furfural degradation.

[0036] During the hydrogenation step hydrogenation reactions utilizing heterogenous catalysts such as Pd / C the hydrogen needs to cross three phase boundaries to be able to react with the substrate: Gas -> Liquid -> Catalyst Surface. It is often necessary to quickly replenish the hydrogen adsorption on the catalyst surface to obtain fast hydrogenation kinetics and to suppress side reactions. Thereto mass transfer solubility of the hydrogen in the liquid is very important. Although the solubility can be improved by increasing operation pressure this often results in significant CAPEX another way is to choose a solvent with high hydrogen solubility.

[0037] As can be seen from Table 1 below, THF and 2-methyl-THF are both solvents that show much higher ability to dissolve hydrogen than water and are comparable to i-PrOH.

[0038] Table 1 Hydrogen solubility data for different solvents

[0039] TFCl P fbarl THF H2O Z-PrOH

[0040] H2 [mg / l]

[0041] 5 1 5.2 1 .6 3.0

[0042] 100 100 605 182 806

[0043] Thereto protic solvents such as water might increase byproduct formation by hydrolysing some of the THF to 1,4-butandiol.

[0044] In the embodiments of the disclosure the solvent typically does not comprise added protic solvents, such as water.

[0045] In the embodiments of the disclosure the solvent typically does not comprise secondary alcohols. In the embodiments of the disclosure the catalyst is Palladium (Pd) on a support. The catalyst support is typically chosen from one or more of alumina, carbon, silica, titania, zirconia, zeolites, cerium oxide, carbon nanotubes, graphene and graphene oxide or hydrotalcites mesoporous materials. Typically, the catalyst is palladium on carbon (Pd / C) or palladium on alumina (Pd / AI2O3).

[0046] The preferred amount of catalyst of the method of the disclosure depends on the amount of catalyst (Pd on a support) to furfural as well as on the amount of active metal (Pd) present on the catalyst support. In the embodiments of the disclosure the ratio of catalyst to furfural is typically between 0.005: 1 and 0.5: 1 by weight, preferably between 0.05: 1 and 0.2: 1 by weight. In the embodiments of the disclosure the amount of metal of the catalyst based on the catalyst total weight is between 0.5 wt-% and 10 wt-%, preferably between 1 wt-% and 5 wt-%, more preferably between 3 wt-% and 5 wt-%. Typically, the amount of metal of the catalyst based on the catalyst total weight is between any of 0.5 wt-%, 0.7 wt-%, 0.8 wt-%, 0.9 wt-%, 1 wt-%, 2 wt-%, 3 wt-%, 4 wt-%, 5 wt-%, 6 wt-%, 7 wt-%, 8 wt-%, 9 wt-% and 10 wt-%. The metal loading of the catalyst is expressed as a weight percentage (wt-%) of the total catalyst (metal and support) weight w / w %. The amount of catalyst to furfural can be in the lower end of the range if the amount of metal is in the higher end of the range. If the metal loading is in the lower end of the range, the amount of catalyst to furfural is preferably in the higher end of the range. Typically, the amount of catalyst to furfural is between 0.005: 1 and 0.1 : 1 and the amount of metal of the catalyst based on the catalyst total weight is between 5 wt-% and 10 wt-% or the amount of catalyst to furfural is between 0.1 : 1 and 0.5: 1 and the amount of metal of the catalyst based on the catalyst total weight is between 0.5 wt-% and 5 wt-%.

[0047] The decarbonylation of the method of the disclosure is conducted under a first atmosphere. Typically, the first atmosphere comprises one or more gases chosen from nitrogen, argon, helium, neon, krypton, and xenon or a mixture thereof. Typically, the first atmosphere comprises gases that do not react under the conditions of the process and the first atmosphere comprises substantially no oxygen and substantially no hydrogen. In some embodiments of the disclosure the first atmosphere substantially comprises or consists of nitrogen and / or argon or the first atmosphere substantially comprises or consists of nitrogen. The first atmosphere can for example be created by pressurizing the reactor three times with 10 bar of nitrogen gas followed by depressurization to remove any air and / or oxygen before the reactor is being pressurized with 10 bar of nitrogen or by any other method know by the skilled person. During the decarbonylation the atmosphere changes as for example carbon monoxide (CO) is formed as reaction product in the end of reaction.

[0048] In the embodiments of the disclosure the reaction time for the decarbonylation is between 30 minutes and 5 hours, preferably between 1 hour and 4 hours, more preferably between 2.5 hours and 3 hours. In a batch process, the reaction time is the duration when the reaction conditions, such as the temperature is kept substantially constant. In a continuous process, the reaction time is the average residence time that the reactants spend in the reactor, which is determined by the reactor volume and the flow rate of the reactants through the system. It is a measure of how long a specific portion of the reactant stream is exposed to reaction conditions.

[0049] The hydrogenation of the method of the disclosure is conducted under a second atmosphere. Typically, the hydrogen is added by flushing the reactor with hydrogen gas before pressurizing the reactor.

[0050] In the embodiments of the disclosure the reaction time for the hydrogenation is between 5 minutes and 5 hours, preferably between 30 min and 4 hours, more preferably between 2.5 hours and 3 hours. In a batch process, the reaction time is the duration when the first atmosphere has been replaced by the second atmosphere and the reaction conditions, such as the temperature is kept substantially constant. In a continuous process, the reaction time is the average residence time that the reactants spend in the reactor, which is determined by the reactor volume and the flow rate of the reactants through the system . It is a measure of how long a specific portion of the reactant stream is exposed to reaction conditions. The ramping time is not included in the reaction time. The heating ramp is for example between 5 and 10 °C / min. In the embodiments of the disclosure the temperature during the decarbonylation is a temperature chosen from temperatures between 200 °C and 270 °C, typically a temperature chosen from temperatures between 220 °C and 250 °C. The temperature is kept substantially constant during the decarbonylation reaction. Typically, the reaction is stopped by cooling the reactor below the boiling point of furan (31°C), before depressurizing the system. Typically, the hydrogen is added by flushing the reactor with hydrogen gas before pressurizing the reactor and conversion of furan to THF at reaction conditions suitable for the hydrogenation reaction. Also, other methods known by the person skilled in the art for removing the first atmosphere and adding hydrogen can be used. The catalyst, solvent, liquid products and possible remaining furfural, remain in the reactor following the decarbonylation of furfural to furan.

[0051] In the embodiments of the disclosure the temperature during the hydrogenation is typically a temperature chosen from temperatures between 200 °C and 250 °C or between 220 °C and 240 °C. Typically, the temperature during decarbonylation is between 200 °C and 270 °C and the temperature during hydrogenation is between 200 °C and 250 °C; the temperature during decarbonylation is between 200 °C and 270 °C, and the temperature during hydrogenation is between 220 °C and 240 °C; the temperature during decarbonylation is between 220 °C and 250 °C and the temperature during hydrogenation is between 200 °C and 250 °C; or the temperature during decarbonylation is between 220 °C and 250 °C, and the temperature during hydrogenation is between 220 °C and 240 °C.

[0052] In the embodiments of the disclosure the total pressure is typically a pressure, including for example the vapour pressure of the solvent at reaction temperature and the initial pressure of the gas of the atmosphere at room temperature, for example the nitrogen pressure in the first atmosphere and the hydrogen pressure in the second atmosphere. The total pressure is chosen from a pressure between 30 bar and 120 bar during the decarbonylation reaction, or alternatively between 40 bar and 60 bar and during the hydrogenation reaction the total pressure is chosen from a pressure between 50 bar and 120 bar, or alternatively between 80 bar and 100 bar.

[0053] In the embodiments of the disclosure typically all condensable products remain in the process between the decarbonylation and the hydrogenation. Condensable products herein refer to products being condensable under standard conditions (normal temperature and pressure, 20 °C and 101.325 kP). This means that substantially all of the catalyst, solvent, liquid products and any remaining furfural remain in the reactor following the decarbonylation of furfural to furan when the first atmosphere is removed, and hydrogen added. Typically, the method of the disclosure described in detail above relates to a method for synthesis of furfural to THF, wherein: a) furfural is reacted in a solvent, typically comprising THF or a derivative thereof, in the presence of a catalyst at a temperature between 200 °C and 270 °C, typically at a temperature between 220 °C and 250 °C, under a first atmosphere, typically comprising substantially no oxygen and / or hydrogen, to obtain furan; b) whereafter the first atmosphere is removed, and hydrogen is added; and c) whereafter the furan of step a) is reacted under a second atmosphere with hydrogen in the presence of the catalyst to obtain THF; wherein the catalyst is Palladium (Pd) on a support, typically palladium on carbon (Pd / C) or palladium on alumina (Pd / ALOs); and no new catalyst is added between steps a) and c). Preferably, the temperature in step a) is between 220 °C and 250 °C and the temperature in step c) is between 220 °C and 240 °C. In this embodiment of the disclosure the amount of furfural in step a) is typically 2 - 3 wt-% based on the total weight of added furfural and solvent. In this embodiment of the disclosure the amount of catalyst to furfural is typically between 0.005: 1 and 0.1 : 1 and the amount of metal of the catalyst based on the catalyst total weight is between 5 wt-% and 10 wt-% or the amount of catalyst to furfural is between 0.1 : 1 and 0.5: 1 and the amount of metal of the catalyst based on the catalyst total weight is between 0.5 wt-% and 5 wt-%. In this embodiment of the disclosure the total pressure in step a) is typically between 30 bar and 120 bar and in step c) between 50 bar and 120 bar or alternatively the total pressure in step a) is between 40 bar and 60 bar in step c) between 80 bar and 100 bar. In this embodiment of the disclosure, the solvent does not comprise secondary alcohols.

[0054] EXAMPLES

[0055] 1 One-Dot conversion of furfural to THF in a li

[0056] Catalytic activity tests were performed in 75m L stainless steel batch reactors (Parr 5000 Series) and mixed with a magnetic stir bar with a stir speed of 1000 rpms. Initially, reactors were filled with 40mL of tetra hydrofuran as solvent (>95 wt.%, Merck Millipore with stabilizer), 0.1 g of solid catalyst, and 1 g of commercial furfural. Prior to the tests, the reactor was flushed three times with 10 bar of nitrogen gas (5.0, Messer) to remove any air / oxygen before then being pressurized with 10 bar of nitrogen. The reaction time was kept at 3 hours of isothermal time. The ramping time which was approximately 20 min with a heating ramp of ~7 °C / min. After the 3-hour reaction, the reactor was cooled with icy water to ensure to be well below the boiling point of furan (31°C), before depressurizing the system.

[0057] In initial tests a 5 wt.% Pd / AI2O3 catalyst was tested at relevant reaction temperatures between 160 °C and 240 °C. The resulting furfural conversion and furan yield are shown in Figure 1. Furfural conversion refers to the percentage of furfural that has reacted or been consumed in the process and furan yield refers to the percentage of the initial furfural that has been converted specifically into furan.

[0058] As shown in Figure 1 a 95-97% furan yield was achieved at 240 °C in 10 bars of N2for 3 hours with lg of furfural and THF as solvent.

[0059] Next both the decarbonylation and the hydrogenation reactions were performed sequentially in one-pot during a batch process. The first reaction (furfural to furan) was performed at 240 °C in 10 bars of N2for 3 hours with lg of furfural and THF as solvent and using 5% Pd / AI2Os or 5% Pd / C catalysts.

[0060] After the 3-hour decarbonylation reaction, the reactor was cooled with icy water to ensure it was well below the boiling point of furan (31°C), before depressurizing the system. The reactor was then flushed with hydrogen gas three times, then pressurized up to 50 bar, where the catalyst, solvent, and liquid products remained in the reactor following the initial test. The reactor was then heated up again for the second step hydrogenation reaction to convert furan to THF. The results when varying the reaction temperature only of the second reaction of furan to THF are shown in Figure 2.

[0061] The results demonstrated that the 5% Pd / C catalyst outperformed the 5% Pd / AI2O3 catalyst at reaction temperature between 220 °C and 240 °C. The maximum that was achievable was ~95% furan conversion at 240°C with the 5 wt.% Pd / C catalyst. The carbon-supported catalyst also demonstrated activity as low as 200 °C whereas the 5% Pd / AI2O3 catalyst showed zero activity already at 210 °C. These results suggest that it is possible to circumvent CO poisoning of the Pd-containing catalyst if the furan to THF reaction is performed at elevated reaction temperatures somewhere in the range of 200 °C to 270 °C or in the range of 220°C to 250°C.

[0062] As the actual THF yield could not be quantified due to THF also serving as the selected solvent for these initial "one-pot" reactions, 2-methyl-THF was used as the solvent to enable the quantification of THF. Based on the optimized reaction condition, "one-pot" furfural conversion to THF was performed with 100 mg of catalyst, 1 g of furfural and 40 mL of 2-methyl-THF. The total reaction time remained the same, 3 hours for each step, where the first step was left the same as previous while the second step of furan hydrogenation was conducted under 50 bars of H2at three different reaction temperatures (220 °C, 240 °C, and 250 °C). Analogous to the activity tests using THF, the 5% Pd / C catalyst outperformed alumina as a support where THF yields were up to 88 % versus 84 %, as shown in Figure 3. The THF yields were based on the initial furfural amount.

[0063] Example 2 Furfural concentration

[0064] Different concentrations of furfural were tested by varying the starting amount of furfural being 1 g (2.7 wt-%), 2 g (5.3 wt-%) and 5g (12.3 wt-%) based on the total weight of added furfural and solvent (w / w %), and the concluding results are shown in Figure 4. Results indicated that nearly complete (100%) furfural conversion remained constant up to 5g of starting furfural. However, furan yield decreased substantially from 96% with lg of furfural to only around 60% with 2g of starting furfural.

[0065] Catalysts with different Pd loadings on both alumina and carbon support were tested at 240 °C, 10 bar N2, 1 g furfural and a reaction time of 3 hours, but with differing catalyst amounts (100 mg and 200 mg). The results are presented in Figure 5a and Figure 5b.

[0066] As shown in Figure 5a, lowering the Pd loading to 1 wt-% resulted in an almost complete loss of activity compared to the test with 5 wt-% Pd / AI2O3 catalyst on the far left of the figure. As shown in Figure 5b, doubling the catalyst amount to 200 mg was able to allow the 1 wt-% Pd / AI2O3 catalyst to achieve comparable results as the 3 wt-% Pd / C catalyst.

[0067] Examole 5 Comoaring different catalysts

[0068] Various Pd and Pt containing catalysts with 5 wt-% metal loadings that were commercially available were tested at a moderate reaction temperature of 210 °C (10 bar N2) for comparative purposes. The concluding furfural conversion and furan yields after a 3-hour reaction time are presented in Figure 6.

[0069] Results clearly indicated that catalysts containing Pt demonstrated very poor (negligible) activity compared to Pd-containing catalysts. Regarding Pd- containing catalysts, furfural conversion was in the range of 90% up to 100%, whereas furan yield was between 45% and 50%.

Claims

CLAIMS1. A method for synthesis of tetra hydrofuran (THF) from furfural, characterized in that a) furfural is reacted in a solvent, in the presence of a catalyst, at a temperature between 200 °C and 270 °C under a first atmosphere to obtain furan; b) the first atmosphere is removed, and hydrogen is added; and c) the furan of step a) is reacted under a second atmosphere with hydrogen in the presence of the catalyst to obtain THF; wherein the solvent comprises THF or a derivative thereof, and wherein the catalyst is Palladium (Pd) on a support.

2. The method according to claim 1, characterized in that the amount of furfural in step a) is 1 - 15 wt-% based on the total weight of added furfural and solvent, preferably the amount is 1 - 13 wt-% and more preferably the amount is 2 - 3 wt-%.

3. The method according to any of the preceding claims, characterized in that the solvent comprises one or more of THF or a derivative thereof, preferably THF or an alkylated derivative of THF, more preferably THF or a methylated derivative thereof.

4. The method according to any of the preceding claims, characterized in that the solvent is THF or a derivative thereof, preferably THF or an alkylated derivative of THF, more preferably THF or a methylated derivative thereof.

5. The method according to any of the preceding claims, characterized in that the solvent comprises THF, 2-methyl-THF, 2,5-dimethyl-THF, 2, 2,5,5- tetramethyl-tetrahydrofuran, tetra hydrofurfuryl alcohol, furfuryl alcohol or mixtures thereof.

6. The method according to any of the preceding claims, characterized in that the solvent is THF, 2-methyl-THF, 2,5-dimethyl-THF, 2,2,5,5-tetramethyl- tetra hydrofuran, tetra hydrofurfuryl alcohol or furfuryl alcohol.

7. The method according to any of the preceding claims, characterized in that the solvent does not comprise added protic solvents.

8. The method according to any of the preceding claims, characterized in that the solvent does not comprise added water.

9. The method according to any of the preceding claims, characterized in that the solvent does not comprise secondary alcohols.

10. The method according to any of the preceding claims, characterized in that the catalyst support is chosen from one or more of alumina, carbon, silica, titania, zirconia, zeolites, cerium oxide, carbon nanotubes, graphene and graphene oxide or hydrotalcites mesoporous materials.

11. The method according to any of the preceding claims, characterized in that the catalyst is palladium on carbon (Pd / C) or palladium on alumina (Pd / AI2O3).

12. The method according to any of the preceding claims, characterized in that the ratio of catalyst to furfural is between 0.005: 1 and 0.5: 1 by weight, preferably between 0.05: 1 and 0.2: 1.

13. The method according to any of the preceding claims, characterized in that the amount of metal of the catalyst based on the catalyst total weight is between 0.5 wt-% and 10 wt-%, preferably between 1 wt-% and 5 wt-%, more preferably between 3 wt-% and 5 wt-%.

14. The method according to any of the preceding claims, characterized in that the first atmosphere comprises substantially no oxygen and / or substantially no hydrogen.

15. The method according to any of the preceding claims, characterized in that the first atmosphere comprises one or more gases chosen from nitrogen, argon, helium, neon, krypton, and xenon or the first atmosphere substantially consists of one or more gases chosen from nitrogen, argon, helium, neon, krypton, and xenon.1616. The method according to any of the preceding claims, characterized in that the first atmosphere substantially comprises or consists of nitrogen and / or argon or the first atmosphere substantially comprises or consists of nitrogen.

17. The method according to any of the preceding claims, characterized in that step a) reaction time is between 30 minutes and 5 hours, preferably between 1 hour and 4 hours, more preferably between 2.5 hours and 3 hours.

18. The method according to any of the preceding claims, characterized in that step c) reaction time is between 5 minutes and 5 hours, preferably between 30 min and 4 hours, more preferably between 2.5 hours and 3 hours.

19. The method according to any of the preceding claims, characterized in that the temperature in step a) is between 220 °C and 250 °C.

20. The method according to any of the preceding claims, characterized in that the temperature in step a) is between 200 °C and 270 °C and the temperature in step c) is between 200 °C and 250 °C, temperature in step a) is between 200 °C and 270 °C, and the temperature in step c) is between 220 °C and 240 °C, in step a) is between 220 °C and 250 °C and the temperature in step c) is between 200 °C and 250 °C, or the temperature in step a) is between 220 °C and 250 °C, and the temperature in step c) is between 220 °C and 240 °C.

21. The method according to any of the preceding claims, characterized in that the total pressure in step a) is between 30 bar and 120 bar or alternatively between 40 bar and 60 bar.

22. The method according to any of the preceding claims, characterized in that the total pressure in step c) is between 50 bar and 120 bar or alternatively between 80 bar and 100 bar.1723. The method according to any of the preceding claims, characterized in that all condensable products remain in the process between step a) and c).

24. The method according to any of the preceding claims, characterized in that no purification or no isolation, for example by distillation or by filtration, is conducted between step a) and step c).

25. The method according to any of the preceding claims, characterized in that no catalyst is added between step a) and step c).

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