DE19615878A1 - High yield selective production of furan-2,5-di:carboxaldehyde - Google Patents

Abstract

Production of furan-2,5-dicarboxaldehyde (FDC) from 5-hydroxymethyl-furan-2-carboxaldehyde (HMF) in a liquid medium comprises: (a) dissolving HMF in a solvent, brought into contact with at least one solid compound (I) containing oxide(s) of Group IVB, VB and/or VIB metals; and heating to 75-200 deg C.

Description

The invention relates to a method for the selective production of Furandicarboxaldehyde-2.5 (FDC) starting from hydroxymethyl-5- Furan carboxaldehyde-2 (HMF).

HMF can be synthesized from vegetable substances Of origin, which may contain or release fructose or polyfructan, for example Jerusalem artichoke juice. HMF consists of a starting product, in the synthesis of numerous furan derivatives, which in turn are in production of polymers that have interesting properties (the possibility special chemical transformations, at temperature and in heat, chemically inert property, mechanical properties and / or special electrical properties or other properties).

Of the numerous derivatives of HMF, FDC is a monomer that Can be the subject of numerous applications. In particular, it can too serve the following: For the synthesis of certain polymers and macro cycles, especially in pharmacy, reticulation agents in the manufacture of special polymers, binders for foundry sands, for the production of Films for separating aqueous solutions from alkaline batteries, as Corrosion inhibitors, as a treatment agent for the surfaces of metals such as copper, nickel, for the synthesis of other symmetrical or asymmetric furan compounds, such as furan-2,5-dicarboxylic acid (FDA).

However, FDC is not manufactured industrially, and lacking one economically viable process that works continuously as well as under Conditions that are compatible with current environmental requirements.  

The known methods for synthesizing FDC are either stoechiometric reactions (which are disadvantageous in that they are polluting, corrosion problems with the plant cause, are expensive and also difficult continuously to perform), or reactions of homogeneous catalysis (which are difficult are to be carried out continuously and which are a separation of the solved Reaction products require).

Oxidation reactions of HMF in heterogeneous catalysis show in that Measures difficulties on in which HMF is not stable at the high Temperatures required to activate solid oxygen catalysts are necessary, whereby the degradation begins at 100 ° C.

The oxidation of HMF in a liquid environment with heterogeneous catalysis has already been described. DE-A-38 26 073 suggests the use of Platinum on activated carbon as a catalyst, at a temperature of 70 ° C, and to oxidize an aqueous solution of HMF. The reaction is not selective with respect to the FDC (with the yield of FDC being 24%), and produced also dicarboxyl-2,5-furanoic acid. The publication "Platinium Catalyzed Oxidation of 5-hydroxymethylfurfural "P. Vinke, H.E. van Dam, H. van Bekkum, New Developments in Selective Oxidation, G. Genti and F. Trifiro Editeur, Elsevier Science Publishers, Amsterdam, Studies in Surface Science and Catalysis, 1990, 55, pp. 147-156, describes an oxidation reaction of HMF in an aqueous environment, catalyzed by platinum on aluminum at 600 in Presence of oxygen. The reaction produces very little FDC and is particularly suitable for the selective production of FFCA.

Numerous aldehyde syntheses are known, starting from alcohols in heterogeneous catalysis. A variety of catalysts have been used in these different reactions used: The majority of pure or alloyed Metal oxides (iron, copper, zinc, silver, nickel, cobalt, magnesium, vanadium,  Zircon, molybdenum, bismuth, antimony), silicon, silicates, zeolites. In the Most of these cases have seen these reactions in a gas phase at high Temperature (more than 200 ° C) carried out. All of these reactions can however do not lead to the oxidation of HMF due to the thermal Instability, which is the reaction that occurs in the liquid phase and at low temperature (below 200 ° C).

In this application, the terms "selectivity", "conversion" and "Yield" used with reference to the definitions below, where C is the conversion, S is the selectivity and A is the yield:

In this connection, the present invention provides a selective one Manufacturing process for FDC based on HMF, especially a such process that produces properties that industrial exploitation enable (little pollution, slightly continuous to carry out, quickly, inexpensively and with a satisfactory yield). In In this context, it should be noted that both the selectivity and the conversion of the process are crucial to the subsequent ones Process steps to facilitate or even avoid the general are expensive and relate to separation or cleaning.  

The invention is in particular to propose a method, the FDC yield is greater than 60% and its selectivity for FDC and whose conversion is both over 90%.

The invention thus relates to a method for the selective production of FDC, starting from HMF in liquid phase and at low temperature (below 200 ° C).

In a method according to the invention is in a liquid Solvent-dissolved HMF contacted with at least one solid Compound containing at least one metal selected from the metals series IV B, V B and VI B of the periodic classification of the elements; the reaction medium is at a temperature between 75 and 200 ° C. brought.

Of the metals in question are titanium, zirconium, To name vanadium, niobium, chromium, molybdenum and tungsten. These metals can be used in pure metallic form or as a salt or preferably in the form of simple or mixed oxides. These metals can also be used in bulk or on a substrate will. In the latter case, the substrate can include a metal or in Silicate form are present, in particular as tectosilicate or argil.

It is best to use a solid compound that contains vanadium oxide. By using vanadium oxide V₂O₅ significantly better Results achieved.

According to the invention, the reaction is in the presence of oxygen made, especially in a reactor in which a gas pressure, containing oxygen. According to the invention it is advantageous to Carry out reaction in a reactor in which an air pressure between  5 · 10⁵ Pa and 30 · 10⁵ Pa prevail. The oxygen allows vanadium oxide, which serves both as an oxidizing agent and as a solid catalyst, constantly to regenerate. More specifically, it would be an oxygen partial pressure maintained enough to put vanadium oxide on one for the reaction maintain optimal oxidation level.

The solid compound can be made from a vanadium oxide in the free, not supported condition (i.e. massive). In this case the The reaction is best carried out at a temperature above 150 ° C best in the order of 170 ° C.

Notwithstanding, according to the invention advantageously as a fixed connection Vanadium oxide used, supported on a metal oxide substrate amphoteric character, preferably acidic. Here one can Achieve a synergy effect between vanadium oxide and its metal oxide carrier, especially when the latter is neither acidic nor basic nor amphoteric is still predominantly basic.

According to the invention, vanadium oxide is best used, carried by a titanium oxide substrate. According to the invention, the titanium oxide carrier is on best made from titanium oxide, containing between 50 and 100% Anatase phase and between 50 and 0% rutile phase, especially in the Anatase phase of 64% and of the order of 36% Rutile phase.

Under these conditions the reaction can be carried out at a very low level Perform temperature, namely lower than 100 ° C, especially in the Of the order of 90 ° C, showing conversion and selectivity achieved by over 90% each.  

The sequence of the method according to the invention depends in the same way on Weight ratio of vanadium in the solid compound. According to the Invention it is advantageous to use a fixed connection between 1% and 56%, in particular 4% by weight of vanadium. Quality Results were obtained with a weight ratio of vanadium in the firm connection of 7 and 7.5%, especially in the order of 7.33%.

It also becomes a fixed connection according to one Mass ratio with respect to the starting amount of HMF between 0.5 and 5 are used, particularly on the order of 2.

According to the invention, HMF is converted into a polar, liquid solvent introduced which is suitable for solving HMF and which remains chemically inert the reaction temperature and compared to the solid compound. According to the polar solvent must be equally suitable for the invention, To solve FDC. According to the invention the solvent is best one aromatic or ketonic solvent.

According to the invention, it is advantageous to use methyl isobutyl acetone (MIBC) as the solvent. This solvent is all the more advantageous as HMF generally results from the synthesis, dissolved in MIBC. According to the invention, the reaction is then carried out at a concentration of starting HMF which is above 6 · 10 ^-2 mol per liter and at an air pressure of above 5 · 10⁵ Pa, in particular of the order of 10 · 10⁵ Pa.

According to the invention, it is also advantageous to use toluene as the solvent. In this case, the reaction according to the invention is carried out at a concentration of starting HMF between 2 · 10 ^-2 and 8 · 10 ^-2 mol per l, and an air pressure of over 10 · 10⁵ Pa, in particular of the order of 16 · 10⁵ Pa.

In the following examples, the reactions were closed Reactor of 100 ml carried out, equipped with a magnetic stirrer, further equipped with an inlet valve for compressed gas and a bleed valve, heated and equipped with a temperature controller.

The HMF used was over 99% pure. It is a clear one yellow solid with a molar mass of 126.11 g, which melts at 35 ° C. FDC is a straw yellow solid with a molar mass of 124 g Absorption wavelength in ultraviolet light of 280 nm.

The predetermined amount of HMF is first selected in 50 ml Solvent then dissolved together with the solid catalyst in the Reactor introduced. After a stirring period there will be a withdrawal made, which allows the initial amount of HMF in the reactor to dose exactly. The reactor is then stirred at 1000 rpm brought to a desired reaction temperature. The response time begins to run when this temperature is reached.

The additions to HMF and FDC are determined by HPLC chromatography at 15, 30, 60, 90, 150, 240 min reaction time carried out.

If the solvent used is toluene, the chromatography column is a monosaccharide H⁺ column. The standard used is the furfural, and the elution solvent is an aqueous solution of trifluorocetic Acid.

If the solvent used is MIPC, the chromatography column a column containing a grafted carrier CN. The used The standard is hydroquinone and the elution solvent is a mixture of Cyclohexane (80%), dichloromethane (16%) and isopropanol (4%).  

example 1

In this example, solid vanadium oxide V₂O₅ is used (not supports), with a mass ratio of the solid V₂O₅ to that in the Reactor introduced HMF = 2. Note that the weight ratio of Vanadium in V₂O₅ is 56. This catalyst is best used during 4 Calcined for hours at 500 ° C. The air pressure is 10 · 10⁵ Pa, the temperature 170 ° C and the solvent is toluene.

First, the thermal stability of HMF at 170 ° C is tested by that it is introduced dissolved in toluene without a catalyst. After 90 minutes a loss of 10% HMF was noted.

In the presence of the catalyst, the selectivities achieved are in the The order of 70% with a conversion of over 90%. After 90 Minutes of reaction time, the conversion is 91%, the selectivity 69% and the yield 62%.

Example 2

The same experiment as in Example 1 is carried out, but free Vanadium oxide is replaced by vanadium, on a titanium oxide carrier in one Anatase phase.

To produce this catalyst, 5 g of titanium oxide anatase distilled water and then at 20 ° C for 20 hours dried. There are 560 mg of NH₄VO₃ a solution of 20 ml of oxalic acid 1M attached. The mixture turns into a midnight blue color heated and the solution is added to the carrier. It will be during 30 Stirred for minutes, then evaporated, then dried at 100 ° C. Of the  The catalyst is then crumbled, sieved and at 450 ° C for 5 hours calcined.

Analysis of the catalyst obtained shows that it is 8.17 percent by weight Vanadium shows (centesimal analysis) on a specific surface of 9 m² / g (Brunauer-Emett-Teller process, nitrogen adsorption Isotherms).

The selectivities obtained are between 60 and 70% Conversion that is over 90% after only 30 minutes of reaction. The Conversion kinetics are therefore very quick. After 90 minutes they are Conversion 95%, selectivity 67% and yield 64%.

Example 3

First solid connections are made from vanadium oxide, carried by a titanium oxide comprising 64% anatase phase and 36% Rutile phase.

10 g of this carrier TIO₂ with a 64% anatase phase and 36% Rutile phase (hereinafter called TIO₂ (A / R), partially de-hydroxylated (TiOH), are dissolved in 250 ml of water in the presence of an amount of between 0.23 g and 4.56 g of metavanadate ammonium (NH₄VO₃). The solution is through The addition of concentrated hydrochloric acid acidified to a pH of 2. The mixture is stirred for 24 hours, then centrifuged, and that Any excess is removed.

The precipitate obtained is washed several times in warm water (70- 100 ° C) washed to remove the excess substances that have not reacted eliminate. After each wash, the mixture is centrifuged, and that Any excess is eliminated.  

The catalyst is then recovered. It is heated to 60 ° C in the oven dried, crushed, sieved (diameter between 0.063 mm and 0.125 mm), and calcined in an air stream at 500 ° C for 4 hours.

The starting amount of NH₄VO₃ is varied. There are catalysts C1 obtained to C6, comprising different proportions of vanadium oxide. The Centesimal analysis has made it possible to measure the amount of vanadium Catalyst and the active phase V₂O₅ with respect to the carrier TiO₂ dose.

The specific area of the catalysts was also Emett-Teller method of nitrogen adsorption isotherms determined.

The following are the various catalysts V₂O₅ on TiO₂ (A / R) through the reference (C1 to C6) of the above table is reproduced.

The same test was carried out as in Example 1 (170 ° C.), however, V₂O₅ without substrate by the catalyst C5 (V₂O₅ on TiO₂ (A / R) 7.33% vanadium) is replaced.  

The selectivities achieved are between 70 and 80% with a conversion, which reaches 80% as soon as the reaction time is equal to or greater than 90 min. With a duration of 90 minutes, the conversion is 80% and the Selectivity 77%.

Example 4

The same test was carried out as in Example 3, but with one Temperature of 90 ° C and an air pressure of 16 · 10⁵ Pa as well as with the Catalysts C5 (7.33% vanadium), TiO₂ (A / R) alone (0% vanadium), V₂O₅ without carrier (56% vanadium) and V₂O₅ on TiO₂ 100% anatase (8.17% Vanadium).

With V₂O₅ without a carrier, the selectivities obtained are between 75 and 80%, but the conversion remains below 30%. The yield remained this temperature below 25%.

With the carrier TiO₂ (A / R) alone, the selectivities achieved are greater than 95 %, but with a conversion of less than 15%. The yield is below 14%.

With V₂O₅ on TiO₂ 100% anatase, the selectivities achieved vary between 75% and 90% if the conversion is less than 40%. The maximum achieved Yield after 240 min was 31%.

With V₂O₅ on TiO₂ (A / R) the selectivities and conversion and thus the Yields significantly higher. The yield is namely over 66% a reaction time of 60 min. After 90 minutes the conversion is 81% with a selectivity of 97%, and thus a yield of 79%. The Selectivities are over 80% with conversions of 54% from one Reaction time of 30 min.  

It can thus be a synergy between V₂O₅ and the carrier at 90 ° C. Determine TiO₂ (A / R) (64% anatase and 36% rutile).

Example 5

Then the results obtained were compared with the others V₂O₅ / TiO₂ (A / R) catalysts of various weight ratios of Vanadium. The tests were carried out under the same conditions as in Example 4 in toluene and then carried out in MIBC, with a Mass ratio of catalyst on HMF of 2 (0.4 g catalyst to 0.2 g HMF in 50 ml solvent). So the conversions and Selectivities and thus the yields for reaction times of 1 and 4 Hours determined.

If one plots the curves according to these tables, it will become clear that the one-layer achieved with a vanadium ratio of over 4% becomes. Accordingly, the proportion of vanadium should advantageously be over 4% lie.

Example 6

With catalyst C5 (7.33% vanadium) the influence of the mass of the Catalyst evaluated for the conversion of HMF, the selectivity of FDC, in toluene and then in MIBC under the conditions of Example 4.

Example 7

With 0.4 g of the catalyst C5 (7.33% vanadium) the influence of Initial set of HMF on the conversion and selectivity of FDC in Toluene and evaluated in MIBC, in 50 ml, under the conditions of Example 4.

Example 8

The influence of the air pressure with catalyst C5 (V₂O₅ on TiO₂ (A / R) at 7.33% vanadium) rated at 90 ° C; the mass ratio of the Catalyst on the substrate was 2 (0.4 g catalyst on 0.2 g HMF) in  Toluene, then in MIBC. The air pressure was between 0 and 26 · 10⁵ Pa changed.

Example 9

There was an influence of temperature between 75 and 110 ° C below them Conditions as examined in Example 8, wherein the air pressure 16 · 10⁵ Pa scam.

It follows from these experiments that the oxidation reaction of HMF in FDC in a liquid environment a satisfactory selectivity and satisfactory Yield at low temperature (below 200 ° C) in the presence of Yields vanadium oxide. In particular, comprising vanadium oxide on titanium oxide between 60 and 70% (ideally 64%).  

Examples 6 and 7 show that the mass ratio of the catalyst HMF can vary between about 0.5 and 5, the same good ones Results are achieved. The best results are at a ratio reached by 2.

While the starting concentration of HMF is over 3.14 · 10 ^-3 mol per 50 ml, for example 6 · 10 ^-2 mol / l, it is preferable to use MIBC (Example 7). If the concentration is instead less than 3.88 · 10 ^-3 mol per 50 ml, e.g. B. 8 · 10 ^-2 mol / l, it is advisable to use toluene.

Example 8 shows, moreover, that the conversion is practically no longer changes (75-80%) from 16 · 10⁵ Pa air in toluene. In MIBC the maximum Conversion (35 to 40%) reached from 10 · 10⁵ Pa air.

Finally, example 9 shows that the conversion at 75 ° C is not very large, that the conversion and selectivity are good at 90 ° C, and that the Selectivity drops at 110 ° C in MIBC.

Based on these results, the industrial, continuous Start production of FDC, for example with an or several stages in the multi-contact reactor, in particular of the type pulsating column, starting from HMF in a liquid phase at 90 ° C in the presence of V₂O₅, in particular on the carrier TiO₂ comprising 64% Anatase phase and 36% rutile phase at 7.33% vanadium.

Of other metal oxides or metal salts that can be used are in particular the oxides or salts of titanium, zirconium, Vanadium, Niobium, Chromium, Molibdane or Tungsten too call. The metal oxides or salts can be in bulk (without carrier or substrate) or used with substrate.

Claims (20)

1. A process for the preparation of furandicarboxaldehyde-2.5 (FDC) starting from hydroxymethyl-5-furancarboxaldehyde-2 (HMF) in a liquid medium, characterized in that HMF dissolved in a liquid solvent is brought into contact with at least one solid compound, which contains at least one metal oxide selected from the metals of the series IV B, VB and VI B of the periodic system of the elements, and that the reaction medium is brought to a temperature between 75 ° C and 200 ° C. 2. The method according to claim 1, characterized in that a fixed Compound is used that contains vanadium oxide. 3. The method according to claim 2, characterized in that a fixed Compound is used that is made from carrier-free vanadium oxide consists. 4. The method according to claim 2, characterized in that as a fixed Vanadium oxide compound is used on a Metal oxide substrate of amphoteric nature in an acidic environment. 5. The method according to claim 4, characterized in that Vanadium oxide is used on titanium oxide as the substrate. 6. The method according to claim 5, characterized in that the substrate made from titanium oxide is made from titanium oxide containing 50-100% Anatase phase and between 50 and 0% rutile phase.   7. The method according to claim 6, characterized in that the substrate made from titanium oxide is made from titanium oxide, comprising 60-75% Anatase phase and between 40 and 25% rutile phase. 8. The method according to claim 7, characterized in that the substrate is formed from titanium oxide containing in the In the order of 64% anatase phase and in the order of 36% rutile phase. 9. The method according to any one of claims 6 to 8, characterized in that the reaction at a temperature below 100 ° C, in particular is carried out in the order of 90 ° C. 10. The method according to any one of claims 2 to 9, characterized in that a fixed connection is used, containing between 1 and 56 weight percent vanadium. 11. The method according to claim 10, characterized in that a fixed Compound is used containing at least 4 percent by weight Vanadium. 12. The method according to any one of claims 1 to 11, characterized characterized in that the fixed connection according to a Mass ratio with respect to the starting amount of HMF used between 0.5 and 5, especially in the Order of magnitude of 2. 13. The method according to any one of claims 2 to 12, characterized characterized in that the reaction in the presence of oxygen a partial pressure is carried out which is sufficient for  Maintaining the vanadium oxide on its for the reaction optimal oxidation level. 14. The method according to claim 13, characterized in that the Reaction is carried out in a reactor in which a gas pressure prevails, comprising oxygen. 15. The method according to claim 14, characterized in that the Reaction is carried out in a reactor in which an air pressure between 5 · 10⁵ Pa and 30 · 10⁵ Pa. 16. The method according to any one of claims 1 to 15, characterized characterized in that the HMF in a liquid polar solvent is given to make the HMF soluble and chemically inert to be left at the reaction temperature compared to the solid Connection. 17. The method according to claim 16, characterized in that the Solvent is methyl isobutyl ketone (MIBC). 18. The method according to claim 17, characterized in that the reaction is carried out at an HMF starting concentration of over 6 · 10 ^-2 mol / l and an air pressure of over 5 · 10⁵ Pa, in particular in the order of 10 · 10⁵ Pa. 19. The method according to claim 16, characterized in that the Solvent is toluene. 20. The method according to claim 19, characterized in that the reaction at an HMF starting concentration between 1 · 10 ^-2 and 8 · 10 ^-2 mol / l and an air pressure of greater than 10 · 10⁵ Pa, in particular in the order of 16 · 10⁵ Pa, is carried out.