WO2025078586A1

Movatterモバイル変換

Info

Publication number: WO2025078586A1
Application number: PCT/EP2024/078663
Authority: WO
Inventors: Jean-Pierre Berkan LINDNER; Ralf Boehling; Wolf-Steffen Weissker; Dagmar Pascale Kunsmann-Keitel; Jens Weiguny
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 2023-10-13
Filing date: 2024-10-11
Publication date: 2025-04-17
Anticipated expiration: 2026-04-13

Abstract

The present application relates to a process for preparing a product mixture comprising hydroxyacetone, to the use of a solid catalyst comprising one or more of copper and compounds of copper in said process, as well as to the use of said mixture for preparing a chipboard.

Description

Due to the presence of two asymmetric carbon atoms (indicated by *) in the ketal molecule, there exist four stereoisomers of the ketal formed by reaction of hydroxyacetone with 1,2-propandiol. Over prolonged time of chemically converting glycerol to hydroxyacetone, organic material (typically compounds having a high-boiling point, especially polymeric and oligomeric ma- terial) may deposit on the surface of the solid catalyst. This leads to a significant reduction of the pore volume and of the surface area of the solid catalyst, and hence in reduced activity of the solid catalyst. Moreover, organic depositions along the catalyst bed may lead to clogging and reduced pore volume (free volume) causing a pressure increase, so that ultimately a shutdown of the reactor may become necessary to avoid catastrophic failure. Surprisingly, it has been found that the solid catalyst comprising one or more of copper and compounds of copper may be regenerated, i.e. its activity and pore volume (free volume) may be restored by means of a regenerating step, wherein regenerating comprises sub- jecting said solid catalyst to an atmosphere comprising oxygen and an inert gas, preferably nitrogen, at a temperature in the range of from 250 °C to 600 °C, preferably in the range of from 250 °C to 300 °C. In said regeneration step, preferably said solid catalyst is exposed to a gas stream comprising nitrogen and oxygen in a volume ratio of from 90:10 to 99:1 for a duration of 2 to 20 hours at a temperature in the range of from 250 °C to 600 °C, prefer- ably in the range of from 250 °C to 300 °C. In said regeneration step, preferably said solid catalyst is exposed to a gas stream consisting of nitrogen and oxygen in a volume ratio of from 90:10 to 99:1 for a duration of 2 hours to 20 hours at a temperature in the range of from 250 °C to 600 °C, preferably in the range of from 250 °C to 300 °C. Therefore, in certain cases a process according to the invention further comprises after step (iii) the following step (iv) regenerating the solid catalyst, wherein regenerating comprises subjecting said solid catalyst to an atmosphere comprising oxygen and an inert gas, preferably nitrogen, at a temperature in the range of from 250 °C to 600 °C, preferably of from 250 °C to 300 °C, wherein preferably in step (iv), said solid catalyst is exposed to a gas stream com- prising nitrogen and oxygen in a volume ratio in the range of from 90:10 to 99:1 for a duration of 2 hours to 20 hours at a temperature in the range of from 250 °C to 600 °C, preferably of from 250 °C to 300 °C. During step (iv) the volume fraction of oxygen in the gas stream may be increased contin- uously or step-wise. The regeneration step (iv) may be carried out at a pressure in the range of from 10 kPa to 200 kPa, preferably in the range of from 50 kPa to 150 kPa, more preferably in the range of from 80 kPa to 120 kPa, most preferably in the range of from 90 kPa to 110 kPa. It is understood that the gas stream to which the solid catalyst is exposed in step (iv) is substantially free of hydrogen, glycerol, propanediol and any other reactants involved in step (iii). Step (iii) is stopped before carrying out step (iv), and before starting the regeneration pro- cedure, the solid catalyst usefully may be flushed with inert gas, e.g. nitrogen, to remove all traces of hydrogen and of the reactants. As mentioned above, the activity and selectivity as well as the pore volume (free volume) of the solid catalyst is maintained for a quite long duration when the chemical conversion of glycerol to hydroxyacteone is carried out using a feed stream comprising 1,2-propanediol beside glycerol. Therefore, advantageously step (iii) can be carried out for a quite long duration before it may become necessary to stop step (iii) and to carry out step (iv) for regenerating the solid catalyst. Preferably step (iv) is carried out after at least 500 hours, more preferably after at least 800 hours, most preferably after at least 1000 hours of chemically converting glycerol into hy- droxyacetone at said solid catalyst (step (iii)), wherein during said at least 500 hours, more preferably during said at least 800 hours, most preferably during said at least 1000 hours step (iii) has preferably been carried out continuously. Typically, step (iv) is carried out when one or more of the following criteria are met: - the content of hydroxyacetone in the product mixture goes below a certain minimum value - the content of glycerol in the product mixture exceeds a certain maximum value - the pressure in the reactor reaches a critical value, so that shutdown of the reactor is necessary to avoid catastrophic failure. In certain cases, it is preferred that step (iii) is stopped and step (iv) is carried out - when in the product mixture the content of hydroxyacetone goes below 40 wt.-%, preferably when in the product mixture the content of hydroxyacetone goes below 50 wt.-%, more preferably when in the product mixture the content of hydroxyace- tone goes below 55 wt.-% and/or - when in the product mixture the content of glycerol exceeds 5 wt.-%, preferably when in the product mixture the content of glycerol exceeds 3 wt.-%, more preferably when in the product mixture the content of glycerol exceeds 2 wt.-%. It is understood by the skilled person that during step (iv), the copper in the solid catalyst may be oxidized. Therefore, step (iv) is usefully followed by an activation procedure of the solid catalyst wherein the activation procedure comprises above-defined step (i.2). In preferred processes according to the invention, one, two or more of the above-defined preferred features are combined. Thus, an especially preferred process according to the invention comprises the following steps (i) providing a solid catalyst comprising copper in reduced form as obtainable by react- ing a pre-catalyst composition comprising one or more oxides of copper with a re- ducing agent, preferably hydrogen (ii) providing a feed stream comprising glycerol and 1,2-propanediol in a mass ratio in the range of from 80:20 to 90:10, preferably 90:10, wherein the feed stream provided in step (ii) substantially consists of glycerol and 1,2-propanediol, to said solid catalyst wherein in step (ii) liquid glycerol and liquid 1,2-propanediol are evaporated in the presence of a carrier gas stream comprising hydrogen and nitrogen, and the feed stream comprising evaporated glycerol and evaporated 1,2-propanediol is carried to the solid catalyst by means of the carrier gas stream consisting of hydrogen and nitrogen, wherein preferably said carrier gas stream comprises hydrogen and nitrogen in a volume ratio in the range of from 5:95 to 4:6, most preferably in the range of from 1:9 to 3:7, (iii) chemically converting glycerol provided in step (ii) with the feed stream into hydrox- yacetone at a temperature in the range of from 220 °C to 250 °C in the presence of hydrogen at said solid catalyst, wherein in step (iii) the pressure is in the range of from 80 kPa to 120 kPa, most preferably in the range of from 90 kPa to 110 kPa, the hydrogen partial pressure is in the range of from 10 kPa to 30 kPa, most prefer- ably in the range of from 20 kPa to 30 kPa, the catalyst load is in the range of from 0.3 kg total mass of glycerol and 1,2-pro- panediol/(kg catalyst * hour) to 0.7 kg total mass of glycerol and 1,2-propanediol/(kg catalyst * hour), the molar ratio of glycerol to hydrogen is in the range of from 1:5 to 4:5, most prefer- ably in the range of from 3:10 to 7:10. wherein the obtained product mixture comprises or consists of - hydroxyacetone in an amount of from 55% to 70%; and - water in an amount 9% to 25%; and - glycerol in an amount of from 0.05% to 3%, most preferably of from 0.1% to 1%; and - 1,2-propanediol in an amount of from 3% to17%, most preferably of from 5% to 15%; and - ethylene glycol in an amount of from 1% to 2%; and - propionic acid in an amount of from 0.6% to 1.2%, most preferably of from 0.7% to 1%; and - lactic acid in an amount of from 0.7% to 3%, most preferably of from 0.9% to 2.5%; and - acetic acid in an amount of from 0.05% to 0.8%, most preferably of from 0.1% to 0.5%; and - formic acid in an amount of from 0.05% to 0.4%, most preferably of from 0.1% to 0.3%, - ketals in an amount of from 1% to 15%, preferably of from 1% to 7%, wherein the % in each case refer to the total mass of the mixture, wherein step (iii) is continued for at least 800 hours, most preferably for at least 1000 hours, and then (iv) regenerating the solid catalyst, wherein regenerating comprises subjecting said solid catalyst to an atmosphere comprising nitrogen and oxygen at a temperature in the range of from 250 °C to 300 °C, wherein in step (iv), said solid catalyst is exposed to a gas stream comprising nitrogen and oxygen in a volume ratio of from 90:10 to 99:1 for a duration of 2 to 20 hours at a temperature in the range of from 250 °C to 300 °C. A further aspect of the invention relates to the use of a solid catalyst comprising one or more of copper and compounds of copper in the above-defined process according to the invention, preferably in a process having one or more of the above-defined preferred fea- tures. For details regarding the solid catalyst comprising one or more of copper and compounds of copper, all information regarding the solid catalyst which is provided above applies mu- tatis mutandis to the use of a solid catalyst comprising one or more of copper and com- pounds of copper in the above-defined process according to the invention. A further aspect relates to a mixture comprising or consisting of - hydroxyacetone in an amount of from 40% to 80%, more preferably of from 50% to 75%, most preferably of from 55% to 70%; and - water in an amount of from 5% to 40%, more, preferably of from 7% to 30%, most preferably of from 9% to 25%; and - glycerol in an amount of from 0% to 5%, more preferably of from 0.05% to 3%, most preferably of from 0.1% to 1%; and - 1,2-propanediol in an amount of from 0% to 20%, more preferably of from 3% to 17%, most preferably of from 5% to 15%; and - ethylene glycol in an amount of from 0% to 4%, more preferably of from 0.5% to 3%, most preferably of from 1% to 2%; and - propionic acid in an amount of from 0.5% to 1.5%, more preferably of from 0.6% to 1.2%, most preferably of from 0.7% to 1%; and - lactic acid in an amount of from 0.5% to 5%, more preferably of from 0.7% to 3%, most preferably of from 0.9% to 2.5%; and - acetic acid in an amount of from 0.01% to 1%, more preferably of from 0.05% to 0.8%, most preferably of from 0.1% to 0.5%; and - formic acid in an amount of from 0.01% to 0.5%, more preferably of from 0.05% to 0.4%, most preferably of from 0.1% to 0.3%, - ketals in an amount of from 1% to 15%, preferably of from 1% to 7%, wherein the % in each case refer to the total mass of the mixture. Said mixture may be obtainable by a process according to the invention as defined above, preferably by a process having one or more of the above-defined preferred features. The above-defined mixture may be used as a component of a binding agent for binding wood chips or lignocellulosic fibers. Especially, the above-defined product mixture may be used as a component of a binding agent for binding wood chips in a process for preparing a chipboard. Advantageously, a product mixture obtained by the process according to the invention as defined above may be used for said purpose without any further purification. In this regard, a binding agent, in particular a binding agent for binding wood chips or lig- nocellulosic fibers, may be a binding agent comprising or consisting of a) component A comprising or consisting of polymer(s) A1 having primary and/or sec- ondary amine groups wherein polymer(s) A1 has/have an NCps of at least 1 wt.-%, and b) component B comprising or consisting of a mixture as defined above. The above-defined binding agent may replace conventional binding agents which have the severe disadvantage of emitting formaldehyde. Compared to a binding agent having a component B consisting of hydroxyacetone, it was observed that a component B as defined above may retard the kinetics of the cross-linking reaction, thereby increasing the pot-time of a premix of above-defined components A and B. Without wishing to be bound by any theory, it is presently assumed that the retarded kinetics may be caused by the organic acids present in component B as defined above, which act as protonation agent for the amine groups of the polymer(s) A1, thus reducing the amount of amines capable to react with hydroxyacetone. Advantageously, a simple temperature trigger (e.g. increased temperature) is usually sufficient to regain the desired reactivity. The increased pot-time of a premix of above-defined components A and B broad- ens the potential applicability of the binding agents towards applications which need more time to apply the binding agent onto a substrate of choice. A mixture as defined above may be used for preparing a chipboard, wherein said chipboard is prepared by binding wood chips by means of a binding agent comprising or consisting of a) component A comprising or consisting of polymer(s) A1 having primary and/or sec- ondary amine groups wherein polymer(s) A1 has/have an NCps of at least 1 wt.-%, and b) component B comprising or consisting of a mixture as defined above. In this regard, a process for preparing a chipboard, may be a process comprising the step of binding wood chips by means of a bonding agent comprising or consisting of a) component A comprising or consisting of polymer(s) A1 having primary and/or sec- ondary amine groups wherein polymer(s) A1 has/have an NCps of at least 1 wt.-% and b) component B comprising or consisting of a mixture as defined above. The primary amine group nitrogen content (NC_p) is the content of nitrogen in wt.-% nitrogen which corresponds to the primary amine groups in polymer(s) A1. The secondary amine nitrogen content (NCs) is the content of nitrogen in wt.-% nitrogen which corresponds to the secondary amine groups in polymer(s) A1. The sum of the primary and secondary amine group nitrogen content of the polymer(s) A1, i.e. the NC_ps, is calculated using the following equation NCps = NCp + NCs The primary amine group nitrogen content (NC_p) and the secondary amine group nitrogen content (NC_s) can be measured based on EN ISO 9702:1998 (determination of primary, secondary and tertiary amine group nitrogen content). Preferably, polymer(s) A1 comprise(s) polymerization product(s) of (i) amino acids, preferably amino acids comprising at least two amine groups, and/or (ii) amines comprising at least two amine groups, wherein the amines are no amino acids, and amino acids, and/or (iii) amines comprising at least two amine groups, wherein the amines are no amino acids, and di and/or tricarboxylic acids, which are no amino acids, and/or (iv) at least two compounds defined in i) to iii). Preferably, the polymer(s) A1 has (have) a total weight-average molecular weight Mw,total of at least 800 g/mol and preferably at most 20,000 g/mol, more preferably at least 1,000 g/mol and preferably at most 10,000 g/mol. More preferably, the polymer(s) A1 comprise(s) at least one polymer selected from the group consisting of (i) polyalkyleneimines, BASF SE 230859 230859WO01 (ii) polyamides, (iii) block copolymers comprising polyalkyleneimine segments and polyamide segments, (iv) graft copolymers comprising polyalkyleneimine segments and polyamide segments and (v) mixtures of at least two of (i), (ii), (iii) and (iv). wherein polymer(s) A1 comprise(s) a polymerization product of amino acids, wherein option- ally at least 50 wt.-% amino acids are used as monomers for the polymerization reaction based on total amount of monomers. Especially preferably, the polymer(s) A1 comprise(s) or consist(s) of poly(amino acids). Most preferably, polymer(s) A1 is/are polylysine(s). A process for preparing a chipboard by binding wood chips by means of a binding agent comprising a) component A comprising polymer(s) A1 having primary and/or secondary amine groups wherein polymer(s) A1 has(have) NCps of at least 1 wt.-%, and b) component B comprising hydroxyacetone is described in WO 2022/136614 A1. Except for the composition of component B of the binding agent, all information provided in WO 2022/136614 A1 applies mutatis mutandis to the process for preparing a chipboard as disclosed herein. Figure 1 is a scheme of an apparatus for the process according to the invention. Step (i) In reactor K2 a solid catalyst comprising one or more of copper and compounds of copper (for instance, in the form of a fixed bed or a fluidized bed) is provided. It is understood by the skilled person that the design of the reactor is not limited to any specific embodiment which may be derived from figure 1. As understood by the skilled person, any suitable type of reactor may be used, and suitable reactor types are within the common general knowledge of the skilled person. Step (ii) A carrier gas stream comprising hydrogen and nitrogen and a liquid stream comprising glycerol and 1,2-propanediol are fed to evaporator R1. In evaporator R1, a gaseous feed stream is prepared by evaporating liquid glycerol and liquid 1,2-propanediol in the presence of the carrier gas stream comprising hydrogen and nitrogen. Said feed stream comprising evaporated glycerol and evaporated 1,2-propane- diol is carried by means of the carrier gas stream to reactor K2 comprising the solid catalyst. It is understood by the skilled person that the design of the evaporator is not limited to any specific embodiment which may be derived from figure 1. As understood by the skilled person, any suitable type of evaporator may be used, and suitable evaporator types are within the common general knowledge of the skilled person. Step (iii) In reactor K2, glycerol is chemically converted to hydroxyacetone at a temperature in the range of from 200 °C to 270 °C in the presence of hydrogen at the solid catalyst. A product mixture comprising hydroxyacetone is drawn from the reactor K2 by means of pump P2. Latent heat of the product mixture is recovered by heat exchanger W2 and used for heating reactor K2. Waste gas leaves reactor K2 via a gas exit at the upper end of reactor K2.

A laboratory scale set-up comprising a U-tube reactor having two segments (the “incoming limb” and “outgoing limb”) is used. The outgoing limb of the U-tube contains a fixed bed comprising a solid catalyst comprising one or more of copper and compounds of copper (30 g of a pre-activated catalyst commercially available from BASF SE in the form of tablets having a diameter of 3 mm). A dense pack of glass wool forms a separator between the incoming limb and the outgoing limb to prevent spilling of the catalyst tablets into the in- coming limb. The incoming limb is devoid of solid material (no catalyst and no inert material filling). The feed stream is entering the U-tube via the incoming limb and passes on to the “outgoing limb”, which contains the catalyst bed. Figure 2 is a schematic representation of the U-tube reactor. The incoming limb and the outgoing limb are indicated by direction arrows. The separator and the catalyst bed are also shown. Before filling into the reactor, the solid catalyst was activated by treating a pre-catalyst composition with hydrogen (for details, see table 1 below), so that a pre-activated solid catalyst was obtained which contains copper in reduced form as obtainable by reacting the pre-catalyst composition comprising one or more oxides of copper with a hydrogen. Table 1: Gas-Feed for catalyst activation duration N₂, heating to 220 °C until reaching 220 °C 5% H₂ + 95% N₂ 30 min 10% H₂ + 90% N₂ 30 min 15% H₂ + 85% N₂ 30 min 20% H₂ + 80% N₂ 30 min 25% H₂ + 75% N₂ 5 hours The reactor was flushed with a carrier-gas mixture of 48 nL/h N₂ and 12 nL/h H₂ and heated to 240 °C. In an example according to the invention, a liquid stream comprising glycerol (purity 99 wt.- %) and 1,2-propanediol in a mass ratio of 9:1 was pumped into a double-jacketed glass- evaporator via an HPLC pump (21 g/h). The evaporator was heated to 225 °C and the non- heated carrier-gas (mixture of 48 nL/h N2 and 12 nL/h H2) passed through the evaporating glycerol and 1,2-propanediol. The gas phase consisting of N2, H2, evaporated glycerol and evaporated 1,2-propanediol was passed through the catalyst bed at 240 °C. In a comparison example, a liquid stream comprising glycerol (purity 99 wt.-%) and no 1,2-propanediol was pumped into a double-jacketed glass-evaporator via an HPLC pump (21 g/h). The evaporator was heated to 225 °C and the non-heated carrier-gas (mixture of 48 nL/h N₂ and 12 nL/h H₂) passed through the evaporating glycerol. The gas phase con- sisting of N2, H2, and evaporated glycerol was passed through the catalyst bed at 240 °C. The whole setup was operated near ambient pressure. After leaving the reactor, the obtained product mixture was condensed by means of an air cooler and a demister containing glass wool. The obtained product mixture was subjected to GC (gas chromatography) analysis. During running the process, the overpressure (difference between actual pressure and at- mospheric pressure) in the reactor and the selectivity towards hydroxyacetone were mon- itored. Results Table 2 shows the development of the overpressure over the running time and a qualitative assessment of the selectivity and conversion derived from the GC analysis results of the product mixture (cf. tables 3 and 4). In tables 2-4 below, the term “running time” refers to the time during which step (iii) was carried out, i.e. the time during which the solid catalyst is used for chemically converting glycerol into hydroxyacetone. Table 2: Comparison example Example according to the invention Feed stream comprising glycerol Feed stream comprising glycerol and and no 1,2-propanediol 1,2-propanediol (mass ratio 9:1) Running qualitative qualitative time/ assessment of overpressure/ assessment of overpressure/ conversion and kP conversion and hours a kPa selectivity selectivity 100 + 7 + 7 200 + 6 + 7 500 + 4 + 8 780 - >40 + 8 1000 + 8 1200 + 8 1600 + 8 1780 + > 40 “+” means high selectivity and conversion; “-“ means no or very low selectivity and conversion During 500 hours, high selectivity and conversion were observed in both examples. How- ever, caused by fouling of the solid catalyst, e.g. depositions organic material (typically compounds having a high-boiling point, especially polymeric and oligomeric material) on the catalyst surface, in the comparison example after a running time of 500 hours the se- lectivity and conversion decrease and the pressure increases, so that ultimately the whole reactor may be blocked. An overpressure above 40 kPa (0.4 bar) is considered as a severe safety risk and causes emergency shutdown of the reactor used for the examples described herein. In the example according to the invention, decrease of selectivity and conversion, fouling of the solid catalyst and ultimate blocking of the reactor occur much later. Indeed, in the example according to the invention, the time period where the solid catalyst has high activity and selectivity is > 1600 hours. Thus, without wishing to be bound by any theory, it is presently assumed that the presence of 1,2propanediol in the feed stream has the effect of suppressing fouling of the solid catalyst. The composition of the product mixture obtained in the comparison example is shown in table 3. The composition of the product mixture obtained in the example according to the invention is shown in table 4. In each case, the composition of the product mixture is de- termined by means of GC analysis. Table 3: Running Product composition/wt.-% time/ hours hydroxyacetone water 1,2-propanediol glycerol unidentified 100 55.69 22.4 10.41 0.15 11.35 200 58.45 20.0 10.06 0.07 11.42 500 64.96 19.2 6.12 0.48 9.24 Table 4: Running Product composition/wt.-% time/ hours hydroxy- 1,2-propane- a_cetone^water_diol^{glycerol other including ketal ketal} 100 53.33 18.8 12.79 0.09 14.99 1.47 200 58.58 20.0 11.01 0.12 10.29 2.44 500 63.22 19.8 9.16 0.30 7.52 1.57 780 64.17 16.5 9.97 0.84 8.52 1.89 1000 60.72 19.2 11.50 1.41 7.17 2.02 1200 62.02 19.1 9.39 2.12 7.37 2.61 1600 59.15 19.0 8.06 3.29 10.5 2.24 1780 57.21 17.8 8.84 2.55 13.6 4.67 In both examples, the conversion and selectivity increase over 500 hours from the begin- ning of the chemical conversion of glycerol to hydroxyacetone. However, while in the com- parison example the chemical conversion of glycerol to hydroxyacetone could be continued for 780 hours only, in the example according to the invention the chemical conversion of glycerol to hydroxyacetone could be continued up to 1780 hours. Regeneration of the solid catalyst During chemical conversion of glycerol to hydroxyacetone, organic material (typically com- pounds having a high-boiling point, especially polymeric and oligomeric material) may de- posit on the surface of the solid catalyst. This leads to a reduction of the pore volume (free volume) and of the surface area of the solid catalyst, and hence in reduced activity of the solid catalyst. Moreover, depositions of organic material (typically compounds having a high-boiling point, especially polymeric and oligomeric material) along the solid catalyst lead to clogging and reduced pore volume (free volume) causing a pressure increase, so that ultimately a shutdown of the reactor used in the above-described examples was nec- essary to avoid catastrophic failure. Although it was shown above that the presence of 1,2-propanediol in the feed stream has the effect of maintaining the activity of the solid catalyst over a prolonged time, finally a point will be reached where the activity of the solid catalyst and/or the pore volume (free volume) in the reactor become unacceptably low. Therefore, in another example, the conversion of glycerol to hydroxyacetone (conditions as in the above-described example according to the invention) was interrupted when a regeneration of the solid catalyst was considered to be necessary (for details see below). The regeneration was carried out according to the following protocol: The hydrogen supply was disconnected from the reactor and the liquid stream comprising glycerol (purity 99 wt.-%) and 1,2-propanediol were stopped. Prior to the regeneration pro- cedure the catalyst bed was flushed with nitrogen to remove all traces of hydrogen. The reactor was heated to a temperature in the range of from 250 °C to 300 °C under nitrogen near ambient pressure. After reaching the required temperature, an oxygen supply was connected to the reactor, and about 5 vol% O₂ were mixed into the gas stream, giving a volume ratio N₂/O₂ of 95:5. The catalyst bed was held under these conditions for 3.5 hours, after which the O₂ amount was increased to 10 vol%, giving a volume ratio of N2/O2 of 9:1. The catalyst bed was held for 10 hours under these conditions (see table 5). After this procedure, the oxygen supply was disconnected from the reactor and the catalyst bed was cooled to room temperature under N₂ atmosphere. Table 5 Gas-Feed for catalyst regeneration duration 100% N₂, Until temperature heating to a temperature in the range of from 250 °C to 300 °C was reached 5% O2 + 95% N2 3.5 hours 10% O2 + 90% N2 10 hours 100% N2, Until room temper- cooling to room temperature ature was reached The hydrogen supply was re-connected to the reactor, and the catalyst activation proce- dure was initiated. To this end, the catalyst bed was heated to 220 °C under a N2 atmos- phere. Subsequently H2 was added to the N2 feed as depicted in table 6. Table 6: Gas-Feed for catalyst activation duration 100% N₂, heating to 220 °C until reaching 220 °C 5% H₂ + 95% N₂ 30 min 10% H₂ + 90% N₂ 30 min 15% H₂ + 85% N₂ 30 min 20% H₂ + 80% N₂ 30 min 25% H₂ + 75% N₂ 5 hours After completion of the activation cycle, the reactor was flushed with a carrier-gas mixture of 48 nL/h N2 and 12 nL/h H2 and heated to 240 °C. The liquid stream comprising glycerol (purity 99 wt.-%) and 1,2-propanediol was resumed, and the chemical conversion of glyc- erol to hydroxyacetone was re-started, wherein chemical conversion of glycerol to hydrox- yacetone was carried out as in the above-described example according to the invention, i.e. a feed stream comprising glycerol (purity 99 wt.-%) and 1,2-propanediol in a mass ratio of 9:1 was pumped into a double-jacketed glass-evaporator via an HPLC pump (21 g/h), the evaporator was heated to 225 °C, the non-heated carrier-gas (mixture of 48 nL/h N₂ and 12 nL/h H₂) passed through the evaporating glycerol and 1,2-propanediol, and the gas phase consisting of N2, H2, evaporated glycerol and evaporated 1,2-propanediol was passed through the catalyst bed at 240 °C. During running the process, the overpressure (difference between actual pressure and at- mospheric pressure) in the reactor and the selectivity towards hydroxyacetone were mon- itored. Table 7 shows the development of the overpressure over the running time and a qualitative assessment of the selectivity and conversion derived from the GC analysis re- sults of the product mixture (cf. table 8). In tables 7 and 8 below, the term “running time” refers to the time during which step (iii) was carried out, i.e. the time during which the solid catalyst is used for chemically converting glycerol into hydroxyacetone. Table 7: Running time/ qualitative assessment of hours_{conversion and selectivity}^{overpressure/kPa} 200 + 6 500 + 6 990 + 20 chemical conversion of glycerol into hydroxyacetone was stopped for carrying out the regeneration and activation procedure as described above 1000 + 4 1500 + 7 2000 + 4 2500 + 4 2526 - 6 chemical conversion of glycerol into hydroxyacetone was stopped for carrying out the regeneration and activation procedure as described above 3000 + 6 “+” means high selectivity and conversion; “-“ means no or very low selectivity and conversion After a running time of 990 hours, the solid catalyst was subject to the regeneration proce- dure described above, because the pressure in the reactor increased significantly, which is an indication of reduction of the free volume in the catalyst bed. After a running time of 2526 hours (1636 hours after the previous regeneration), the solid catalyst was again subject to the regeneration procedure because the content of glycerol in the product mixture increased significantly, which is an indication of reduction of the activity of the solid catalyst due to deposition of organic material on the surface of the solid catalyst. The composition of the product mixture as determined by means of GC analysis is shown in table 8. Table 8: Running time/ Product composition/wt.-% hours H^ydroxy- water 1,2-pro-^glyce Others includ- a_{cetone panediol}^rol_{ing ketal}^ketal 200 58.34 21.5 12.01 0.12 8.03 1.25 500 59.61 23.2 10.47 0.15 6.57 1.63 990 60,84 12,1 13,09 0.4 13,57 1.29 1000 64.69 26.4 6.99 0.73 1.19 1.64 1500 62.11 17.0 7.94 0.42 12.53 1.90 2000 59.11 17.3 7.71 1.09 14.79 1.78 2500 58.34 14.7 7.79 2.34 16.83 2.36 2526 58,76 14,31 7,65 2.5 16,78 2.31 3000 63.66 19.2 7.77 0.28 9.09 2.03 As shown in tables 7 and 8, the above-defined regeneration procedure enables the solid catalyst to be used for further 1500 hours during which the solid catalyst exhibits high con- version and selectivity as well as high free volume. Production of chipboards A mixture comprising a) an aqueous solution comprising 50 wt.-% of Polylysine-1 as component A b) a crosslinker solution (for details see below) as component B was used for preparing a chipboard. Raw materials: For component A of binding agent: Polylysine-1 having a weight-average molecular weight M_w of 2,149 g/mol (prepared ac- cording to Example 1 of WO 2022/136613 by thermal treatment of L-lysine. For component B of binding agent: Hydroxyacetone-containing product mixture obtained by the process according to the pre- sent invention, resp. a hydroxyacetone solution commercially available from Thermo Sci- entific (comparison examples), for details see below. Chips: Spruce wood chips from Germany, Institut für Holztechnologie Dresden. Production of spruce wood chips The chips were produced in a disc chipper. Spruce trunk sections (length 250 mm) were pressed with the long side against a rotating steel disc, into which radially and evenly dis- tributed knife boxes are inserted, each of which consists of a radially arranged cutting knife and several scoring knives positioned at right angles to it. The cutting knife separates the chip from the round wood and the scoring knives simultaneously limit the chip length. Af- terwards, the produced chips are collected in a bunker and from there they are transported to a cross beater mill (with sieve insert) for re-shredding with regard to chip width. After- wards the re-shredded chips were conveyed to a flash drier and dried at approximately 120 °C. The chips were then screened into two useful fractions (B: ≤ 2.0 mm x 2.0 mm and > 0.32 mm x 0.5 mm; C: ≤ 4.0 mm x 4.0 mm and > 2.0 mm x 2.0 mm), a coarse fraction (D: > 4.0 mm x 4.0 mm), which is re-shredded, and a fine fraction (A: ≤ 0.32 mm x 0.5 mm). A mixture of 60 wt.-% of fraction B and 40 wt.-% of fraction C is used as chips for single- layered chipboards (“core layer chips”). Measured parameters and measuring methods Residual particle moisture content: The moisture content of the chips before application of the binder was measured according to EN 322:1993 by placing the particles in a drying oven at a temperature of (103 ± 2) °C until constant mass has been reached. The water content of the chip/binder composition mixtures obtained in step a) of the pro- cess to produce chipboards as defined below is determined in an analogous manner. For this, a sample of the respective mixture (ca.20 g) is weighed in moist condition (m₁) and after drying (m0). The mass m0 is determined by drying at 103 °C to constant mass. BASF SE 230859 230859WO01 Water content is calculated as follows: water content [in wt.-%] = [(m1 – m0)/m0] * 100. Press time factor: The press time factor is the press time (time from closing to opening of the press) divided by the target thickness of the board. The target thickness refers to the board at the end of pressing step c) of the process to produce chipboards as defined below and is adjusted by the press conditions, i.e., by the distance between the top and bottom press plate, which is adjusted by inserting two steel spacing strips in the press. Press time factor [s/mm] = time from closing to opening of the press [s] / target thickness of the pressed board [mm]. For example, when a 10 mm chipboard is made with a press time of 80 s, a press time factor of 8 s/mm results. of the boards: The density of the boards was measured according to EN 323:1993 and is reported as the arithmetic average of ten 50 mm × 50 mm samples of the same board. Transverse tensile strength of the boards (“internal bond”): Transverse tensile strength of the boards (“internal bond”) was determined according to EN 319:1993 and is reported as the arithmetic average of ten 50 mm × 50 mm samples of the same board. Determination of the weight-average molecular weight M_w of polylysine: M_w was determined by size exclusion chromatography under the following conditions: ^ Solvent and eluent: 0.1% (w/w) trifluoroacetate, 0.1 M NaCI in distilled water ^ Flow: 0.8 mL/min ^ lnjection volume: 100 µL ^ Samples are filtrated with a Sartorius Minisart RC 25 (0.2 µm) filter ^ Column material: hydroxylated polymethacrylate (TSKgel G3000PWXL) ^ Column size: inside diameter 7.8 mm, length 30 cm ^ Column temperature: 35 °C ^ Detector: DRI Agilent 1100 UV GAT-LCD 503 [232 nm] ^ Calibration with poly(2-vinylpyridine) standards in the molar mass range from 620 to 2,890,000 g/mol (from PSS, Mainz, Germany) and pyridine (79 g/mol) ^ The upper integration limit was set to 29.01 mL ^ The calculation of M_w includes the lysine oligomers and polymers as well as the monomer lysine. Process to produce chipboards from wood chips: The process comprises the steps a) preparing resinated wood chips; b) pre-pressing the resinated chips under ambient temperature to obtain a pre-pressed chip mat; c) pressing the pre-pressed chip mat in hot press to obtain a chipboard. Step a): preparing resinated chips; The term “resinated chips” is used for the mixture of the chips with the binder composition and additionally added water. In a pre-heated mixer at 40 °C, 112.2 g of polylysine solution comprising 50 wt.-% of Pol- ylysine-1 in water (component A) was sprayed onto 1144.0 g (1100 g dry weight plus 44.0 g water from residual chip moisture content) of spruce core layer chips (moisture content 3.8%, pre-heated to 40 °C) while mixing. Immediately, 19.8 g of an aqueous crosslinker solution (component B, for composition, see below) was sprayed onto the mixture while mixing. In examples CB-2, CB-3, CB-5 and CB-6, a product mixture obtained by the process ac- cording to the present invention was used as the crosslinker source. Said mixture com- prises - 69.4% hydroxyacetone (determined by gas chromatography), - 89.5% total content of organics (determined by gas chromatography in combination with nuclear magnetic resonance spectroscopy, - 10.5% water (determined by gas chromatography). Thus, the active crosslinker content of the product mixture obtained by the process accord- ing to the present invention is - in the minimum 69.4 wt.-% (assuming that only the hydroxyacetone present in the mixture participates in crosslinking polylysine in the chipboard) - in the maximum, 89.5 wt.-% (assuming that the total organics present in the mixture participate in crosslinking polylysine in the chipboard). In comparison examples CB-1 and CB-4, a hydroxyacetone solution commercially availa- ble from Thermo Scientific was used as the crosslinker source. Said solution comprises - 96.4 wt.-% hydroxyacetone (determined by gas chromatography), - 2.3 wt.-% water (determined by gas chromatography), resulting in a total organics content of 97.7 wt.-%. In examples CB-1 and CB-4, 19.8 g of an aqueous crosslinker solution comprising 50 wt.- % hydroxyacetone (source: 96.4 wt.-% hydroxyacetone solution commercially available from Thermo Scientific) was applied. Here, 19.8 g of said aqueous solution contain 10.3 g of the hydroxyacetone solution commercially available from Thermo Scientific. In examples CB-2 and CB-5, 19.8 g of an aqueous crosslinker solution comprising 50 wt.- % hydroxyacetone (source: product mixture obtained by the process according to the pre- sent invention, hydroxyacetone content: 69.4 wt.-%) was applied. Here, 19.8 g of said aqueous solution contain 14.3 g product mixture obtained by the process according to the present invention. In examples CB-3 and CB-6, 19.8 g of an aqueous crosslinker solution comprising 50 wt.- % total organics (source: product mixture obtained by the process according to the present invention, total organics content: 89.5 wt.-%) was applied. Here, 19.8 g of said aqueous solution contain 11.3 g product mixture obtained by the process according to the present invention. BASF SE 230859 230859WO01 Additional water was sprayed during mixing to adjust the final moisture of the resinated chips to 10.0 wt.-%. In examples CB-1 and CB-4, the additional water for adjustment of the final moisture con- tent of the resinated chips to 10.0 wt.-% was 7.2 g. In examples CB-2 and CB-5, the additional water for adjustment of the final moisture con- tent of the resinated chips to 10.0 wt.-% was 9.8 g. In examples CB-3 and CB-6, the additional water for adjustment of the final moisture con- tent of the resinated chips to 10.0 wt.-% was 6.6 g. After the addition of water, the mixing was continued at 40 °C, so that the total mixing time amounted to 3 min. Calculation of the binder content (total of polylysine and crosslinker as explained above) relative to the weight of the dry chips: (112.2 g polylysine solution × 50% + 19.8 g crosslinker solution × 50%) : 1100 g dry weight of chips = 6.0% Calculation of the weight ratio of polylysine vs. the crosslinker as explained above: (112.2 g polylysine solution × 50%) / (19.8 g crosslinker solution × 50%) = 85 : 15 Calculation of the moisture content of the chips/binder mixture: Examples CB-1 and CB-4: Total weight of water = 112.2 g × 50% (from polylysine solution) + (19.8 g – 10.3 g × 97.7%) (from crosslinker solution) + 7.2 g (additional water) + 44.0 g (residual chips moisture) = 117.0 g Total weight of board-forming material = 112.2 g × 50% (from polylysine solution) + 10.3 g × 97.7% (from crosslinker solution) + 1100 g (dry chips) = 1166 g Resulting moisture content = 117.0 g / 1166 g = 10.0% Examples CB-2 and CB-5: Total weight of water = 112.2 g × 50% (from polylysine solution) + (19.8 g – 14.3 g × 89.5%) (from crosslinker solution) + 9.8 g (additional water) + 44.0 g (residual chips moisture) = 116.9 g Total weight of board-forming material = 112.2 g × 50% (from polylysine solution) + 14.3 g × 89.5% (from crosslinker solution) + 1100 g (dry chips) = 1169 g Resulting moisture content = 116.9 g / 1169 g = 10.0% Examples CB-3 and CB-6: Total weight of water = 112.2 g × 50% (from polylysine solution) + (19.8 g – 11.1 g × 89.5%) (from crosslinker solution) + 6.6 g (additional water) + 44.0 g (residual chips moisture) = 116.6 g Total weight of board-forming material = 112.2 g × 50% (from polylysine solution) + 11.1 g × 89.5% (from crosslinker solution) + 1100 g (dry chips) = 1166 g Resulting moisture content = 116.6 g / 1166 g = 10.0% The water content was in each case confirmed by the method according to EN 322:1993 as described above resulting in a water content of 10%. Step b): pre-pressing under ambient temperature; Immediately after resination or after closed storage at 40 °C for 60 min, 600 g of the chips/binder mixture were scattered into a 30 cm × 30 cm mold and pre-pressed under ambient conditions (0.4 N/mm²), so that a pre-pressed chip mat was obtained. Step c): pressing in hot press. Subsequently, the pre-pressed chip mat thus obtained was removed from the mold, trans- ferred into a hot press, and pressed to a thickness of 10 mm to give a chipboard (temper- ature of the press plates 210 °C, maximum pressure 4 N/mm², pressing time 80 s). The data in table 9 (density and internal bond of chipboards, average of ten samples for each example) show that chipboards produced with the product mixture obtained by the process according to the present invention exhibit a strong internal bond (CB-2 and CB-3) on the same level like the chipboards obtained with commercially available hydroxyacetone solution (CB-1). Considering that for CB-3 the amount of the product mixture obtained by the process ac- cording to the invention is reduced by 22% in comparison to CB-2, no deterioration can be observed despite the lower amount of hydroxyacetone present. Thus, it is assumed that other organic constituents of the product mixture obtained by the process according to the invention participate in crosslinking polylysine. Without wishing to be bound by theory, it is assumed that the ketal present in the product mixture obtained by the process according to the invention and/or hydroxyacetone formed by decomposition of said ketal during press- ing the chipboards participate in crosslinking polylysine. Furthermore, if the resinated chips are stored for 60 min before being pressed, the internal bond of the chipboard with commercially available hydroxyacetone (CB-4) is weaker than for the boards with the mixture (CB-5 and CB-6) according to this invention. Without wishing to bound by any theory, it is presently assumed that this advantage may be explained by the presence of species having a lower reactivity such as the ketal of hydroxyacetone which are not prone for curing on the chips before pressing. Finally, considering that for CB-6 the amount of the product mixture obtained by the pro- cess according to the invention is reduced by 22% in comparison to CB-5 no deterioration can be observed despite the lower amount of hydroxyacetone present. Table: 9: Amount of crosslinker Storage source in time of Thickness Internal c^rosslinker resinat Density E_xample ed bond s_ource crosslinker solution chips [mm] [kg/m³] [N/mm²] [g] [min] C^{B-1* Thermo} S_cientific^{10.3 — 9.8 637 0.69} CB-2 Product 14.3 — 9.7 624 0.69 mixture obtained by the process CB-3 according 11.1 — 9.9 614 0.67 to the invention BASF SE 230859 230859WO01 C^{B-4* Thermo} S_cientific^{10.3 60 9.8 621 0.43} CB-5 Product 14.3 60 9.7 640 0.53 mixture obtained by the process CB-6 according 11.1 60 9.8 620 0.52 to the invention * Comparative Example.

Claims

Claims 1. Process for preparing a product mixture comprising hydroxyacetone, said process comprising the following steps: (i) providing a solid catalyst comprising one or more of copper and compounds of copper (ii) providing a feed stream comprising glycerol and 1,2-propanediol to said solid catalyst (iii) chemically converting glycerol into hydroxyacetone at a temperature in the range of from 200 °C to 270 °C in the presence of hydrogen at said solid catalyst. 2. Process according to claim 1, wherein the feed stream provided in step (ii) comprises glycerol and 1,2-propanediol in a mass ratio in the range of from 70:30 to 95:5, preferably in a mass ratio in the range of from 80:20 to 90:10. 3. Process according to any preceding claim, wherein in step (ii) said feed stream is prepared by evaporating liquid glycerol and liquid 1,2-propanediol, wherein preferably in step (ii) liquid glycerol and liquid 1,2-propanediol are evapo- rated in the presence of a carrier gas stream comprising hydrogen and nitrogen, and the feed stream comprising evaporated glycerol and evaporated 1,2-propanediol is carried to the solid catalyst by means of the carrier gas stream, wherein preferably said carrier gas stream comprises hydrogen and nitrogen in a volume ratio in the range of from 1:99 to 1:1, preferably in the range of from 5:95 to 4:6, most preferably in the range of from 1:9 to 3:7. 4. Process according to any preceding claim, wherein said solid catalyst comprises copper in a total amount in the range of from 20 mass-% to 98 mass-%, relative to the total mass of metals present in the solid catalyst. 5. Process according to any preceding claim, wherein said solid catalyst further com- prises one or more of further elements from the group consisting of Al, La, Ti, Zr, Cr, Mo, W, Mn, Ni, Co, Zn, Si, C, alkali metals and alkaline earth metals, preferably aluminum, and compounds of said elements, wherein Al, La, Ti, Zr, Cr, Mo, W, Mn, Ni, Co, Zn, Si, alkali metals and alkaline earth metals are preferably present in the form of oxo compounds, wherein preferably the total mass of copper, elements from the group consisting of Al, Zr, Ti, Zn, Cr, La, Mn, Co, Si, C, alkali metals and alkaline earth metals, com- pounds of copper and compounds of elements from the group consisting of Al, La, Ti, Zr, Cr, Mo, W, Mn, Ni, Co, Zn, Si, alkali metals and alkaline earth metals makes up for 90% or more, more preferably for 95% or more, of the total mass of the solid catalyst, wherein said solid catalyst preferably comprises (a) one or more of copper and compounds of copper and (b) one or more of aluminum and compounds of aluminum, wherein preferably the atomic ratio Cu:Al is in the rage of from 0.5:1 to 2:1. 6. Process according to any preceding claim, wherein said solid catalyst is supported by a support material, wherein preferably the support material is selected from the group consisting of metal oxides, zeolites and carbon-based materials, preferably selected from the group consisting SiO₂, porcelain, magnesium oxide, tin dioxide, silicon carbide, ZrO₂, ZnO, TiO₂, Al₂O₃, aluminum silicate, magnesium silicate, zir- conium silicate, cerium silicate, carbon black, graphite, clay and mixtures of these support materials and/or wherein said solid catalyst is present in the form of a fixed bed or in the form of a fluidized bed. 7. Process according to any preceding claim, wherein step (i) comprises (i.1) providing or preparing a pre-catalyst composition comprising one or more ox- ides of copper, in a total amount in the range of from 20% to 98%, preferably of from 50% to 85%, more preferably of from 55% to 80%, relative to the total mass of the pre-catalyst composition, wherein said pre-catalyst composition preferably has a BET surface area of 15 m²/g or greater, more preferably 15 m²/g to 100 m²/g (i.2) reacting the pre-catalyst composition prepared or provided in step (i.1) with a reducing agent, preferably hydrogen, preferably at a temperature in the range of from 120 °C to 230 °C, more preferably of from 160 °C to 230 °C. 8. Process according to any preceding claim, wherein said feed stream provided in step (ii) comprises glycerol obtained from biomass. 9. Process according to any preceding claim, wherein in step (iii) the temperature is in the range of from 220 °C to 260 °C, preferably in the range of from 220 °C to 250 °C, and/or the pressure is in the range of from 10 kPa to 200 kPa, preferably in the range of from 50 kPa to 150 kPa, more preferably in the range of from 80 kPa to 120 kPa most preferably in the range of from 90 kPa to 110 kPa, and/or the hydrogen partial pressure is in the range of from 1 kPa to 50 kPa, preferably in the range of from 10 kPa to 40 kPa, more preferably in the range of from 10 kPa to 30 kPa, most preferably in the range of from 20 kPa to 30 kPa, and/or the catalyst load is in the range of from 0.1 kg total mass of glycerol and 1,2-propanediol/(kg catalyst * hour) to 1 kg total mass of glycerol and 1,2-propanediol/(kg catalyst * hour), preferably 0.2 kg total mass of glycerol and 1,2-propanediol/(kg catalyst * hour) to 0.8 kg total mass of glycerol and 1,2-propanediol/(kg catalyst * hour), most preferably in the range of from 0.3 kg total mass of glycerol and 1,2-propanediol/(kg catalyst * hour) to 0.7 kg total mass of glycerol and 1,2-propanediol/(kg catalyst * hour), and/or the molar ratio of glycerol to hydrogen is in the range of from 1:10 to 1:1, preferably in the range of from 1:5 to 4:5, most preferably in the range of from 3:10 to 7:10. 10. Process according to any preceding claim, wherein said product mixture comprises hydroxyacetone in an amount of from 40% to 80%, based on the total mass of the product mixture, wherein said product mixture preferably comprises hydroxyacetone in an amount of from 40% to 80%, more preferably of from 50% to 75%, most preferably of from 55% to 70%; and water in an amount of from 5% to 40%, more, preferably of from 7% to 30%, most preferably of from 9% to 25%; and glycerol in an amount of from 0% to 5%, more preferably of from 0.05% to 3%, most preferably of from 0.1% to 1%; and 1,2-propanediol in an amount of from 0% to 20%, more preferably of from 3% to 17%, most preferably of from 5% to 15%; and ethylene glycol in an amount of from 0% to 4%, more preferably of from 0.5% to 3%, most preferably of from 1% to 2%; and propionic acid in an amount of from 0.5% to 1.5%, more preferably of from 0.6% to 1.2%, most preferably of from 0.7% to 1%; and lactic acid in an amount of from 0.5% to 5%, more preferably of from 0.7% to 3%, most preferably of from 0.9% to 2.5%; and acetic acid in an amount of from 0.01% to 1%, more preferably of from 0.05% to 0.8%, most preferably of from 0.1% to 0.5%; and formic acid in an amount of from 0.01% to 0.5%, more preferably of from 0.05% to 0.4%, most preferably of from 0.1% to 0.3%, ketals in an amount of from 1% to 15%, preferably of from 1% to 7%, wherein the % in each case refer to the total mass of the mixture. 11. Process according to any preceding claim, further comprising after step (iii) the fol- lowing step (iv) regenerating the solid catalyst, wherein regenerating comprises subjecting said solid catalyst to an atmosphere comprising oxygen and an inert gas, pref- erably nitrogen, at a temperature in the range of from 250 °C to 600 °C, pref- erably in the range of from 250 °C to 300 °C, wherein preferably in step (iv), said solid catalyst is exposed to a gas stream comprising nitrogen and oxygen in a volume ratio of from 90:10 to 99:1 for a duration of 2 hours to 20 hours at a temperature in the range of from 250 °C to 600 °C, preferably in the range of from 250 °C to 300 °C, wherein preferably step (iv) is carried out after at least 500 hours, more pref- erably after at least 800 hours, most preferably after at least 1000 hours of chemically converting glycerol into hydroxyacetone at said solid catalyst. 12. Use of a solid catalyst comprising one or more of copper and compounds of copper, preferably of a solid catalyst as defined in any of claims 4 to 6, in a process according to any of claims 1 to 11. 13. Use of a mixture as defined in claim 10 for preparing a chipboard, wherein said chip- board is prepared by binding woodchips by means of a binding agent comprising a) component A comprising polymer(s) A1 having primary and/or secondary amine groups wherein polymer(s) A1 has(have) NC_ps of at least 1 wt.-%, and b) component B comprising a mixture as defined in claim 10.