Epoxy resin based on isoeugenol

Abstract

The invention relates to a novel epoxy resin based on isoeugenol. The object of the invention is to synthesize plastics, in particular epoxy resins, fiber-reinforced plastics, etc., based on renewable resources, especially for cabin construction in the aerospace industry, with a significantly increased bio-content, whereby the highest possible glass transition temperatures and a high crosslinking density are to be achieved. This object is achieved according to the invention by a bio-based epoxy resin monomer called triglycidyl isoeugenol (3EPO-IEU) according to claim 1 and a byproduct called diglycidyl allyl isoeugenol (2EPO-rA-IEU) according to claim 2. Furthermore, the object is achieved by a process according to claim 3 for the synthesis of triglycidyl isoeugenol from a provided solution, suspension, or emulsion of isoeugenol, whereby the also usable byproduct is formed. The product and the byproduct can be used alone or as a mixture.

Description

[0001] The invention relates to a new epoxy resin based on isoeugenol.

[0002] Synthetic resins, such as epoxy or phenolic resins, are reactive resins that react with a hardener to form a thermosetting plastic. Synthetic resins are often reinforced with fibers, creating fiber-reinforced plastics (FRP). Fiber-reinforced plastics (FRP) are the synergistic combination of their individual components: load-bearing fibers and a protective and shape-defining plastic matrix. Due to their outstanding properties and diverse manufacturing technologies, FRPs are used in the electronics, sports and leisure industries, boatbuilding, plant and wind turbine construction, the automotive sector, and especially in aviation. Examples include cabin components made of phenolic resin-based FRP and the load-bearing structure of the Airbus A350, which contains over 50% FRP by weight. 1,2,3,4,5,6,7

[0003] The use of fiber-reinforced composites (FRCs) is primarily due to their excellent mechanical properties. FRCs exhibit comparable stiffness and strength to conventional materials, such as metals, despite significantly lower density. The resulting weight reduction enables, among other things, energy savings in the form of reduced fuel consumption in automobiles and aircraft. 8,9,10

[0004] Although fiber-reinforced composites (FRCs) offer many advantages, they also have some disadvantages: compared to metals, they typically exhibit lower thermal stability and / or flame resistance, and thermoplastic-based systems tend to creep under load, often making them unsuitable for components subjected to continuous, high stress. Some of these disadvantages can be mitigated by using cross-linked plastics, so-called thermosets, and by carefully selecting the underlying type.

[0005] Depending on the class used, thermosets exhibit high heat resistance, are intrinsically flame-resistant, and generally show very little creep. The thermosets used for flame-resistant applications and in aircraft cabin construction are mostly phenol-formaldehyde resins. 11,12,13,14

[0006] Although phenolic resins exhibit the highest fire resistance of all plastics, they crosslink via polycondensation. Due to the condensation products formed in this type of reaction, a poor surface finish is achieved. This results in complex, costly, and time-consuming (manual) post-processing of cabin components manufactured from phenolic resins.

[0007] Therefore, the use of epoxy resins in cabin construction is a goal of the aviation industry. This class of thermosets reacts via a polyaddition reaction to form thermosets. As a result, epoxy resins exhibit a significantly higher surface quality after curing.

[0008] Conventional epoxy resin formulations are typically based on fossil raw materials. However, a looming shortage of fossil resources is a major concern in the materials industry. Consequently, the pressure to reduce petroleum use and emissions will increase further in the future.

[0009] To meet the challenges of a modern and sustainable society, new concepts must be adopted. One possibility is the development of bio-based fiber-reinforced composites (FRCs) from renewable resources. Combined with an epoxy resin matrix, this not only meets the ever-increasing demands for sustainability but also avoids the high costs associated with post-processing.

[0010] The bio-Lufa project aims to research fiber-reinforced plastics (FRPs) based on renewable resources for cabin construction in aviation, with the goal of replacing FRPs produced from non-renewable or fossil sources in the future. However, current bio-based epoxy resins, in particular, do not meet the high demands of the aviation industry, including their thermo-mechanical and mechanical properties. This challenge will be addressed through the synthesis of novel epoxy resin monomers from aromatic natural products.

[0011] A wide variety of organic raw materials can be obtained from renewable resources, which can also be further processed into technically relevant materials.

[0012] Lignin is a promising natural resource for aromatic compounds. A biopolymer and a major component of wood, lignin is the second most abundant naturally occurring material on Earth. Commercially, it is obtained as a low-value waste product from paper and ethanol production. 15 However, valuable aromatic compounds such as vanillin, as well as eugenol or isoeugenol, which occurs in larger proportions in id R., can be obtained through depolymerization. 16, 17,18 Isoeugenol is a constitutional isomer of eugenol, differing only in the position of one double bond. Due to its three functional groups (methoxy, hydroxyl, and propenyl residues), isoeugenol can be modified to form an epoxide with two or three epoxide groups.

[0013] Neither the synthesis of the isoeugenol-based glycidyl monomers described here nor their curing has been described before. STATE OF THE ART

[0014] Triglycidyl isoeugenol (3EPO-IEU) and diglycidyl allyl isoeugenol (2EPO-rA-IEU, "r" for "rearranged") have not yet been mentioned in the literature. Nevertheless, isoeugenol-based epoxy resins have already been described in publications, although the structural arrangement of the monomers differs significantly. The most structurally similar molecules are in Figs. summarized.

[0015] Isoeugenol-based epoxides

[0016] Figs. Glycidyl monomers based on isoeugenol, already described in the literature and used for curing epoxy resins. 19, 20, 21, 22, 23, 24, 25, 26, 27

[0017] As from Figs.As can be seen, two triglycidyl-isoeugenol monomers have already been described, but these consisted of two or three isoeugenol units, respectively. A triglycidyl-isoeugenol based on a single isoeugenol molecule has not yet been described. However, the triglycidyl-isoeugenol has the advantage that the monomer is smaller for the same number of epoxy groups, which increases the crosslinking density in the cured epoxy resin. This suggests improved properties such as a higher glass transition temperature and thus also greater temperature stability.

[0018] Another disadvantage of the published work is that amine hardeners have not yet been used to crosslink the isoeugenol monomers. However, amine-cured epoxy resins are more chemically resistant than anhydride-cured ones, making them better suited for high-performance applications.

[0019] Comparisons of the properties of eugenol-based and isoeugenol-based epoxy resins are known from the literature. For example, diglycidyl isoeugenol was investigated, and the monomers were cured with carboxylic acids, alcohols, or predominantly anhydrides. However, François et al. were unable to establish a clear trend between diglycidyl isoeugenol and diglycidyl eugenol regarding the glass transition temperatures achieved. Both monomers, however, exhibited lower glass transition temperatures than the petrochemical reference bisphenol A diglycidyl ether (DGEBA). 28, 29

[0020] The object of the invention is to synthesize plastics, in particular epoxy resins, fiber-reinforced plastics, etc., based on renewable resources, especially for cabin construction in aviation, with a significantly increased bio-content, whereby the highest possible glass transition temperatures and a high crosslinking density are to be achieved.

[0021] This problem is solved according to the invention by a bio-based epoxy resin monomer called triglycidyl isoeugenol (3EPO-IEU) according to claim 1 and a by-product called diglycidyl allyl isoeugenol (2EPO-rA-IEU) according to claim 2. The three epoxide groups of triglycidyl isoeugenol enable a higher crosslinking density than previously described larger molecules with three epoxide groups consisting of several isoeugenol units, while simultaneously providing a small molecular size.

[0022] The problem is further solved by a process according to claim 3 for the synthesis of triglycidyl isoeugenol (3EPO-IEU) from a provided solution, suspension, or emulsion of isoeugenol, wherein the byproduct diglycidyl allyl isoeugenol (2EPO-rA-IEU) is formed. This byproduct can also be used, particularly for applications with lower requirements. This increases the overall yield to 46 wt% or 58 wt%.

[0023] The synthesis pathway essentially comprises 4 synthesis steps with the intermediate products A-IEU, rA-IEU, EPO-rA-IEU and the final product triglycidyl-isoeugenol (3EPO-IEU, monomer).

[0024] In the first stage, a synthesis of allyl isoeugenol (A-IEU) is carried out by allylation of the isoeugenol, in particular by adding sodium hydroxide powder to a provided solution of isoeugenol, especially in dimethyl sulfoxide (DMSO), under a protective gas atmosphere and stirring the mixture for 10 min before adding allyl bromide dropwise, followed by at least one washing and drying process.

[0025] In the second step, rAllylisoeugenol (rA-IEU) is synthesized via a Claisen rearrangement. The intermediate rA-IEU is an orange-brown oil.

[0026] In the third step, the glycidyl ether of rAllylisoeugenol (EPO-rA-IEU) is synthesized by epoxidation of the hydroxyl group with epichlorohydrin. Alternatively, epoxidation with epibromohydrin is also possible.

[0027] The first three process steps were also used analogously in the subsequently published DE102024123117A1, where the starting material was eugenol. The two processes differ particularly in the fourth process step, in which the synthesis of triglycidyl-isoeugenol (3EPO-IEU) is carried out by epoxidation of the double bonds using oxones. ®The reaction is carried out, producing diglycidyl-allyl-isoeugenol (2EPO-rA-IEU) as a byproduct. Diglycidyl-allyl-isoeugenol can be crosslinked via its two epoxide groups. While it exhibits a lower crosslink density than triglycidyl-isoeugenol (3EPO-IEU), which has three epoxide groups, it does have a comparatively low viscosity. Since the byproduct is still usable, the overall yield increases to 46 wt% or 58 wt%. The epoxidation of the double bonds is accelerated by the slow dropwise addition of oxone. ® to a solution of EPO-rA-IEU at temperatures below 5 °C.

[0028] Specific reaction conditions of the invention are described in more detail in the dependent claims.

[0029] Suitable solvents for the isoeugenol in the first stage include polar solvents, preferably butanol, acetonitrile, acetone, isopropanol, water, dimethylformamide (DMF), and dimethyl sulfoxide (DMSO). DMSO is particularly suitable as a solvent and is therefore especially preferred.

[0030] In the first stage, allyl halides, allyl ethyl carbonate, allyl methyl carbonate, diallyl carbonate, allyl alcohol or allyl trimethylammonium chloride, preferably allyl bromide or allyl chloride, in particular allyl bromide, are used as the allylation reagent(s).

[0031] Furthermore, potassium iodide, alkaline solutions, potassium carbonate, tripropylamine, sodium sulfite can be used as reagent(s) in the first stage; alkaline solutions, especially sodium hydroxide, are preferred.

[0032] The first-stage reaction can take place at temperatures between 0 °C and 100 °C, preferably a temperature range between 20 °C and 70 °C, and in particular a temperature range between 25 °C and 40 °C. Stirring is carried out for at least 1 h to 24 h, preferably 2 h to 6 h, and in particular 4 h, until the reaction is largely complete.

[0033] The allylation of isoeugenol in the first step is carried out, for example, by adding sodium hydroxide powder (NaOH) to the prepared solution of isoeugenol in dimethyl sulfoxide (DMSO), stirring the resulting mixture for approximately 10 minutes. Allyl bromide is added dropwise over a period of, for example, 1 hour at 40 °C. This is followed by several hours of stirring, e.g., 4 hours at 40 °C and then 30 minutes at 60 °C. This reaction should preferably be carried out under a protective gas atmosphere. A protective gas atmosphere can be created, for example, by evacuating the apparatus (to 20 mbar) and then purging it with nitrogen. This process can be repeated several times to optimize the protective gas concentration. After washing and concentration steps, the intermediate product A-IEU is obtained as a yellow liquid.

[0034] In the second stage, the intermediate product A-IEU is stirred under protective gas, whereby DMF, xylenes or toluene can be used as solvents, but preferably no solvent is used.

[0035] The Claisen rearrangement (second stage) can be carried out at a temperature of 80 °C to 250 °C, preferably a temperature range between 170 °C and 225 °C, and particularly preferably a temperature of 200 °C. The reaction can proceed for between 0.5 h and 24 h, preferably between 2 h and 10 h, and particularly 5 h.

[0036] Zinc chloride, bismuth triflate and / or ethylene glycol can also be added as a catalyst, but preferably a catalyst is omitted.

[0037] The second stage can alternatively be carried out in a microwave and / or a pressure reactor, but preferably without either of the aforementioned devices.

[0038] In the third stage, (non)polar solvents are used, preferably tert-butanol, methyl ethyl ketone (MEK), benzene, dimethylformamide (DMF), acetonitrile, tetrahydrofuran (THF) or dioxane; however, it is particularly preferred that no solvent is used.

[0039] In the third stage, the intermediate product rA-IEU is mixed with epibromohydrin or epichlorohydrin, preferably with epichlorohydrin and a phase transfer catalyst, and stirred at 0 °C to 100 °C, preferably at 70 °C to 90 °C, particularly at 80 °C for 1 to 24 h, preferably 1 to 6 h, particularly 3 h.

[0040] In the third stage, sodium hydroxide (NaOH) and a phase-transfer catalyst are dissolved in water and added dropwise to the mixture. The reaction mixture is stirred for approximately 1 hour at room temperature.

[0041] Benzyltriethylammonium chloride, hexadecyltrimethylammonium bromide, 18-crown-6, potassium tert-butoxide, tetraethylammonium bromide, preferably tetrabutylammonium bromide (TBAB) are used as phase transfer catalysts.

[0042] After completion of the third stage reaction, the reaction mixture is extracted, e.g. with ethyl acetate, washed several times, e.g. with distilled water and once with saturated NaCl solution, the organic layer is separated and dried for several hours, e.g. with sodium sulfate, to obtain the intermediate product EPO-rA-IEU.

[0043] In the fourth step, in which the synthesis of triglycidyl isoeugenol (3EPO-IEU) takes place through epoxidation of the double bonds, peracids, oxones are formed. ® Potassium peroxomonosulfate, hydrogen peroxide, tert-butyl hydroperoxide, carbamide peroxide, trimethylsilyl peroxide, preferably chloroperbenzoic acid (mCPBA), oxone ®, potassium peroxomonosulfate, especially oxone ® used as epoxidizing reagent(s).

[0044] Furthermore, in the fourth stage, a solvent mixture of water, a polar solvent and a ketone, preferably water, methanol or ethyl acetate or dimethyl sulfoxide (DMSO) with acetone or methyl ethyl ketone (MEK), in particular a water, ethyl acetate, acetone mixture, is used as the solvent.

[0045] As a further reaction condition, it is provided that in the fourth stage the solution is stirred for 1 h to 30 h, preferably 3 h to 28 h, in particular 24 h at -40 °C to 40 °C, preferably -25 °C to 25 °C, in particular 0 °C to 25 °C.

[0046] A particularly advantageous side effect arises from the formation of the byproduct diglycidyl-allyl-isoeugenol (2EPO-rA-IEU) in the fourth stage. While this byproduct exhibits a lower crosslinking density upon curing, it is nevertheless suitable for applications with less stringent requirements or where a lower viscosity is desired. This significantly increases the overall yield of the process.

[0047] The synthesis process according to the invention is described below again with reference to specific embodiments carried out in the laboratory. The syntheses of both examples are the same; the difference lies in the purification of the crude products.

[0048] Powdered sodium hydroxide (9.6 g, 240 mmol, 1.2 eq) was added to a solution of isoeugenol (32.84 g, 200 mmol, 1 eq) in dimethyl sulfoxide (DMSO) (250 ml), and the resulting mixture was stirred for 10 min. The apparatus was evacuated three times (20 mbar) and purged with nitrogen to create a protective atmosphere. Allyl bromide was added via a septum on the dropping funnel using a syringe and needle. The allyl bromide (19.86 ml, 27.81 g, 230 mmol, 1.2 eq) was added dropwise over a period of 1 h at 40 °C. The mixture was then stirred for 4 h at 40 °C and subsequently for 30 min at 60 °C. The reaction mixture was poured into 300 ml of water and then extracted three times with 50 ml of chloroform each time.

[0049] The organic layer was washed twice with saturated NaCl solution, dried over sodium sulfate, and concentrated using a rotary evaporator to obtain A-IEU as a yellow liquid.

[0050] The subsequent synthesis step was carried out using a thermal conversion method. A-IEU had to be stirred for 5 hours at 200 °C in a three-necked flask with a septum, gas balloon, and reflux condenser under protective gas to induce a Claisen rearrangement. The product rA-IEU was obtained as an orange-brown oil in quantitative yield.

[0051] rA-IEU (7 g, 34 mmol, 1 eq), epichlorohydrin (15.88 g, 172 mmol, 5 eq), and tetrabutylammonium bromide (TBAB, 1.1 g, 3.4 mmol, 0.1 eq) were added successively to a three-necked round-bottom flask equipped with a magnetic stirrer and Dimroth condenser. The mixture was stirred for 3 hours at 80 °C. During this time, 5.44 g of NaOH (136 mmol, 4 eq) and 1.1 g of TBAB (3.4 mmol, 0.1 eq) were dissolved in 30 mL of water, followed by the addition of this solution dropwise at room temperature after the three-hour reaction time. The reaction mixture was then stirred for a further 1 hour at room temperature.

[0052] After completion of the reaction, the reaction mixture was extracted with 20 ml of ethyl acetate and washed three times with distilled water and once with saturated NaCl solution, followed by separation of the organic layer and drying overnight with sodium sulfate. The dried organic layer was then concentrated under vacuum and dried for 24 h at 45 °C in a vacuum oven to obtain EPO-rA-IEU as a brown liquid.

[0053] EPO-rA-IEU (2 DB) (5 g, 19 mmol, 1 eq) was dissolved in 80 ml water and 80 ml ethyl acetate (EA) and cooled to 0 °C. NaHCO3 (14.38 g, 171 mmol, 5 eq), Bu4NHSO4 (0.58 g, 1.72 mmol, 0.05 eq), and acetone (25.4 ml, 19.91 g, 342 mmol, 10 eq) were added slowly. Oxone ®(aq) (31.58 g in 250 ml, 0.4 M in water, 103 mmol, 3 eq) had to be added slowly, keeping the temperature below 5 °C. The reaction mixture was stirred at approximately 10 °C for 4 h and then overnight at room temperature. Work-up of the reaction was carried out by adding EA (80 ml), washing the organic phase with 160 ml water and 160 ml salt solution, drying with Na₂SO₄, followed by evaporation of the solvent to obtain the orange-brown product. The crude yield of all four synthesis steps was 83 wt%. Example 1

[0054] Since the epoxidation of the two double bonds in the final step is incomplete (approximately 40% 2EPO-rA-IEU and approximately 60% 3EPO-IEU according to GC / MS measurements), the two components were separated by column chromatographic purification, and further byproducts were isolated. The yield of 3EPO-IEU after column chromatography was 33 wt%, and that of 2EPO-rA-IEU was 13 wt%, resulting in a total yield of 46 wt% of epoxide monomers. Example 2

[0055] To avoid the complex column chromatographic purification, a clarification filtration (KF) was carried out in the second example, whereby the two products are not separated from each other, but the impurities from further by-products and oxidation products can be largely removed.

[0056] For this purpose, 5.5 g of the crude product from synthesis step 4 were dissolved in 30 ml of a solvent mixture of ethyl acetate and petroleum ether (50:50 mixture), and 20 g of silica gel were added. A further 20 g of silica gel were prepared with the solvent mixture between two sheets of filter paper in a Büchner funnel. The suspension containing the crude product was then poured onto the prepared Büchner funnel and washed with the solvent mixture. After removal of the solvent and drying, a slightly yellowish product with a mass of 3.8 g (70 wt%) was obtained.

[0057] The figures illustrate the structure of triglycidyl-isoeugenol and diglycidyl-allyl-isoeugenol and their respective bio-components. They show: Figs. 1. A GC spectrum of triglycidyl-isoeugenol as crude product after epoxidation using Oxone. ® , Figs.2 a GC spectrum and an MS spectrum of a purified triglycidyl isoeugenol (3EPO-IEU), Figs. 3 one 1 H-NMR spectrum (left) and a 13 C-NMR spectrum (right) of triglycidyl isoeugenol (3EPO-IEU), Figs. 4 a GC spectrum and an MS spectrum of a purified by-product diglycidyl-allyl-isoeugenol (2EPO-rA-IEU), Figs. 5 one 1 H-NMR spectrum (left) and 13 C-NMR spectrum (right) of diglycidyl-allyl-isoeugenol (2EPO-rA-IEU), Figs. 6 DMA measurement curves of hardened samples with isoeugenol monomers or references and isophorone diamine (IPDA), Figs. 7 DMA measurement curves of hardened samples with isoeugenol monomers or references and 4,4'-diaminodiphenylsulfone (DDS) and Figs.8 a bar chart showing glass transition temperatures of the hardened synthesized monomers and the hardened references bisphenol-A diglycidyl ether (DGEBA) and triglycidyl eugenol (3EPO-EU).

[0058] Figs. Figure 1 shows a GC spectrum of the triglycidyl-isoeugenol according to the invention as a crude product after epoxidation using Oxone. ® The structure identification and the production of the pure resin plates were always carried out using the purified substances. The actual structure obtained was determined by GC / MS as well as 1 Dog 13 C-NMR spectra ( Figs. 2 and Figs. 4 or Figs. 3 and Figs. 5) checked.

[0059] Figs. 3 and Figs. 5 show a 1 H-NMR spectrum (left) and a 13 C-NMR spectrum (right) of triglycidyl-isoeugenol (3EPO-IEU). 1The ¹H NMR spectrum allows the reading of chemical shifts of resonance lines relative to a standard. This chemical shift is characteristic of substituents or functional groups that replace a hydrogen atom in a molecule. From this, conclusions can be drawn about the structure of the resulting compound. In addition to the... Figs. 3 and Figs. 5 shown on the left 1 H-NMR spectra are also those in Figs. 3 and Figs. 5 shown on the right 13 13C NMR spectra are helpful in elucidating the structure of the resulting compound. The NMR spectra confirm that triglycidyl isoeugenol (3EPO-IEU) and diglycidyl allyl isoeugenol (2EPO-rA-IEU) were synthesized via the described route.

[0060] Using GC-MS measurements, mixtures of substances are first separated by gas chromatography (GC) based on their different boiling points and polarities. The separated individual substances are then ionized by mass spectrometry (MS) to obtain the mass-to-charge ratio (m / z), which provides information about the molar mass. In the GC spectrum ( Figs. 2 and Figs. 4) A splitting of the peaks can be observed; this results from the presence of different enantiomers, which arise from the cis / trans isomers of the starting material isoeugenol. Isoeugenol occurs mainly as trans-isoeugenol; however, the cis isomer is also present in the starting material used. Production and characterization of hardened epoxy resins

[0061] The two synthesized epoxy resin monomers and the mixture of both resulting from clarification filtration were cured with two different amine-based hardeners: isophorone diamine (IPDA, bio-content 73 wt%) and 4,4'-diaminodiphenyl sulfone (DDS). These were then compared with reference samples prepared from bisphenol A diglycidyl ether (DGEBA) with a bio-content of 33 wt% or from triglycidyl eugenol (3EPO-EU) and the same hardeners. The bio-content of all mixtures is shown in Table 1 below. The mixing ratio was adjusted using the previously determined epoxy equivalent to achieve a primary amine-to-epoxide ratio of 1:2. Table 1: Bio-components of the pure resin panels. bio-Anteel / Ma% CATTLE 3EPO-EU 3EPO-IEU 2EPO-rA-IEU IPDA 41 74 74 78 DDS 24 48 48 56

[0062] Depending on the sample, curing took place at temperatures from 40 °C to max. 180 °C when using IPDA, or at temperatures from 120 °C to 240 °C when using DDS (see Table 2). Table 2: Curing conditions of the pure resin boards. Härtungs-Bedingungen CATTLE 3EPO-EU 3EPO-IEU 2EPO-rA-IEU Gemisch KF IPDA 5 min 40 °C,30 min 80 °C,30 min 100 °C,15 min 120 °C 5 min at 40 °C, 5 min at 40 °C, 5 min at 40 °C, 30 min at 80 °C, 30 min at 60 °C, 30 min at 60 °C, 30 min at 100 °C, 30 min at 80 °C, 30 min at 80 °C, 30 min at 120 °C, 30 min at 100 °C, 30 min at 100 °C, 30 min at 140 °C 15 min at 120 °C, 15 min at 120 °C, 15 min at 140 °C, 15 min at 140 °C, 15 min at 160 °C, 15 min at 160 °C 5 min at 180 °C DDS 10 min at 120 °C, 10 min at 120 °C, 120 min at 180 °C, 180 min at 160 °C, 120 min at 240 °C, 150 min at 200 °C, 120 min at 240 °C,

[0063] Figs. Figure 6 shows DMA measurement curves of hardened samples with isoeugenol monomers or references and IPDA and Figs. 7 DMA measurement curves of hardened samples with isoeugenol monomers or references and DDS.

[0064] The values ​​of the glass transition temperatures (temperature at the maximum of tanδ) are in Figs. 8 and Table 3 are compared.

[0065] Figs. Figure 8 shows a bar chart with glass transition temperatures of the synthesized monomers and the references DGEBA and 3EPO-EU. Table 3: Glass transition temperatures of the pure resin plates depending on the mixtures. T g / °C CATTLE 3EPO-EU 3EPO-IEU 2EPO-rA-IEU Gemisch KF IPDA 155 204 189 81 145 DDS 238 269 220 194 194

[0066] This demonstrated that the newly synthesized triglycidyl-isoeugenol, due to its high glass transition temperatures (189 °C and 220 °C), represents a good alternative to DGEBA. The additional possibility of using the byproduct 2EPO-rA-IEU (T g For applications with lower requirements (81 °C and 194 °C), an overall yield of 46 wt% can be achieved after four synthesis steps and column chromatographic purification. Simpler purification via clarification filtration can increase the overall yield to 58 wt%; the glass transition temperatures of the mixture, at 145 °C and 194 °C, lie between the individual values. 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US5962547 20) François, C.; Pourchet, S.; Boni, G.; Rautiainen, S.; Samec, J.; Fournier, L.; Robert, C.; Thomas, C.M.; Fontaine, S.; Gaillard, Y.; Placet, V.; Plasseraud, L.: Design and Synthesis of Biobased Epoxy Thermosets from Biorenewable Resources, Comptes Rendus. Chimie, 2017, 20 (11-12), 1006-1016. https: / / doi.org / 10.1016 / j.crci.2017.10.005. 21) François, C.; Pourchet, S.; Boni, G.; Fontaine, S.; Gaillard, Y.; Placet, V.; Galkin, M.V.; Orebom, A.; Samec, J.; Plasseraud, L.: Diglycidylether of Iso-Eugenol: A Suitable Lignin-Derived Synthon for Epoxy Thermoset Applications, RSC Adv. 2016, 6 (73), 68732-68738. https: / / doi.org / 10.1039 / C6RA15200G. 22) Pourchet, S., Sonnier, R., Ben-Abdelkader, M., Gaillard, Y., Ruiz, Q., Placet, V., Plasseraud, L., Boni, G.: ACS Sustainable Chemistry & Engineering, 2019, 7 (16), 14074-14088. https: / / doi.org / 10.1021 / acssuschemeng.9b02629 23) Ruiz, Q.; Pourchet, S.; Placet, V.; Plasseraud, L.; Boni, G. New Eco-Friendly Synthesized Thermosets from Isoeugenol-Based Epoxy Resins. Polymers, 2020, 12, 229. https: / / doi.org / 10.3390 / polym12010229 24) Carrick, C.; Samec, J.: Process for making lignin composition, 2017. WO 2017084824 25) Hanson, K. G.; Lin, C.-H.; Abu-Omar, M. M.: Crosslinking of renewable polyesters with epoxides to form bio-based epoxy thermosets, Polymer, 2022, 238, 124363. https: / / doi.org / 10.1016 / j.polymer.2021.124363 . 26) Lin, C. H.; Lin, C. M.; Gao, W. J.; Chen, C. H.: Self-curable epoxy resins composition, preparation method thereof and epoxy curable product prepared thereby, 2020. TWI709585 27) Savonnet, E.; Defoort, B.; Cramail, H.; Grelier, S.; Grau, E.: Biphenyl polyepoxide compounds, preparation and uses, 2019. WO2019092359 28) François, C.; Pourchet, S.; Boni, G.; Rautiainen, S.; Samec, J.; Fournier, L.; Robert, C.; Thomas, C.M.; Fontaine, S.; Gaillard, Y.; Placet, V.; Plasseraud, L.: Design and Synthesis of Biobased Epoxy Thermosets from Biorenewable Resources, Comptes Rendus. Chimie, 2017, 20 (11-12), 1006-1016. https: / / doi.org / 10.1016 / j.crci.2017.10.005. 29) François, C.; Pourchet, S.; Boni, G.; Fontaine, S.; Gaillard, Y.; Placet, V.; Galkin, M.V.; Orebom, A.; Samec, J.; Plasseraud, L.: Diglycidylether of Iso-Eugenol: A Suitable Lignin-Derived Synthon for Epoxy Thermoset Applications, RSC Adv. 2016, 6 (73), 68732-68738. https: / / doi.org / 10.1039 / C6RA15200G. ZITATE ENTHALTEN IN DER BESCHREIBUNG

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 102024123117A1

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[0066] Marsh, G.: Wing worker for the world, Reinforced Plastics, 54 (No. 3), 2010, pp. 24-28

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[0066] Rommel, S.; Geiger, R.; Schneider, R.; Bergold, D.; Schneider, M.; Großmann, M.; Kopp, G.; Schmitt, A.: Lightweight construction in mobility and manufacturing - opportunities for Baden-Württemberg, 2012, http: / / www.ipa.fraunhofer.de / fileadmin / www.ipa.fhg.de / Publikationen / Leichtbaustudie.pdf, accessed on 16.01.2015

[0066] Domininghaus, H: In: Eyerer, P.; Hirth, T.; Elsner, P. (eds.): Plastics. Properties and Applications, Springer-Verlag, Berlin, Heidelberg, 2008, pp. 7-8; pp. 27-29; pp. 52-60; pp. 1200-1230

[0066] Schürmann, H: Designing with Fiber-Reinforced Plastics, Springer-Verlag, Berlin, Heidelberg, 2007, pp. 1-12; pp. 21-81; pp. 125-126; pp. 129-132

[0066] Witten, E.; Jahn, B.: Composites Market Report 2011: Market developments, trends, challenges and opportunities, 2011, http: / / www.avk-tv.de / files / 20110929_marktbericht_2011_englisch.pdf, accessed on 13.05.2021

[0066] Eickenbusch, H.; Krauss, O.: Material innovations for sustainable mobility and energy supply, Association of German Engineers, Düsseldorf, 2014, p. 66

[0066] Bajwa, DS; Pourhashem, G.; Ullah, A.H.; Bajwa, SG: A concise review of current lignin production, applications, products and their environmental impact, Industrial Crops and Products, 2019, 139, 111526. https: / / doi.org / 10.1016 / j.indcrop.2019.111526

[0066] Kuroda, K.-I.; Inoue, Y.; Sakai, K. Analysis of Lignin by Pyrolysis-Gas Chromatography. I. Effect of Inorganic Substances on Guaiacol-Derivative Yield from Softwoods and Their Lignins. Journal of Analytical and Applied Pyrolysis 1990, 18 (1), 59-69. https: / / doi.org / 10.1016 / 0165-2370(90)85005-8

[0066] Nowakowski, D. J.; Bridgwater, A. V.; Elliott, D. C.; Meier, D.; de Wild, P. Lignin Fast Pyrolysis: Results from an International Collaboration. Journal of Analytical and Applied Pyrolysis 2010, 88 (1), 53-72. https: / / doi.org / 10.1016 / j.jaap.2010.02.009

[0066] Wang, L.; Zhang, R.; Li, J.; Guo, L.; Yang, H.; Ma, F.; Yu, H. Comparative Study of the Fast Pyrolysis Behavior of Ginkgo, Poplar, and Wheat Straw Lignin at Different Temperatures. Industrial Crops and Products 2018, 122, 465-472. https: / / doi.org / 10.1016 / j.indcrop.2018.06.038

[0066] Nikolic, N. A.; Schultz, R. A.: Reactive radiation- or thermallyinitiated cationically-curable epoxide monomers and compositions made from those monomers, 1999. US5962547

[0066] François, C.; Pourchet, S.; Boni, G.; Rautiainen, S.; Samec, J.; Fournier, L.; Robert, C.; Thomas, C. M.; Fontaine, S.; Gaillard, Y.; Placet, V.; Plasseraud, L.: Design and Synthesis of Biobased Epoxy Thermosets from Biorenewable Resources, Comptes Rendus. Chimie, 2017, 20 (11-12), 1006-1016. https: / / doi.org / 10.1016 / j.crci.2017.10.005

[0066] François, C.; Pourchet, S.; Boni, G.; Fontaine, S.; Gaillard, Y.; Placet, V.; Galkin, M. V.; Orebom, A.; Samec, J.; Plasseraud, L.: Diglycidylether of Iso-Eugenol: A Suitable Lignin-Derived Synthon for Epoxy Thermoset Applications, RSC Adv. 2016, 6 (73), 68732-68738. https: / / doi.org / 10.1039 / C6RA15200G

[0066] Pourchet, S., Sonnier, R., Ben-Abdelkader, M., Gaillard, Y., Ruiz, Q., Placet, V., Plasseraud, L., Boni, G.: ACS Sustainable Chemistry & Engineering, 2019, 7 (16), 14074-14088. https: / / doi.org / 10.1021 / acssuschemeng.9b02629

[0066] Ruiz, Q.; Pourchet, S.; Placet, V.; Plasseraud, L.; Boni, G. New Eco-Friendly Synthesized Thermosets from Isoeugenol-Based Epoxy Resins. Polymers, 2020, 12, 229. https: / / doi.org / 10.3390 / polym12010229

[0066] Carrick, C.; Samec, J.: Process for making lignin composition, 2017. WO 2017084824

[0066] Hanson, K. G.; Lin, C.-H.; Abu-Omar, M. M.: Crosslinking of renewable polyesters with epoxides to form bio-based epoxy thermosets, Polymer, 2022, 238, 124363. https: / / doi.org / 10.1016 / j.polymer.2021.124363

[0066] Lin, C. H.; Lin, C. M.; Gao, W. J.; Chen, C. H.: Self-curable epoxy resins composition, preparation method thereof and epoxy curable product prepared thereby, 2020. TWI709585

[0066] Savonnet, E.; Defoort, B.; Cramail, H.; Grelier, S.; Grau, E.: Biphenyl polyepoxide compounds, preparation and uses, 2019. WO2019092359

[0066]

Claims

Bio-based epoxy resin monomer called Triglycidyl-Isoeugenol (3EPO-IEU) with the structural formula: Bio-based epoxy resin monomer named diglycidyl allyl isoeugenol (2EPO-rA-IEU, "r" for "rearranged") and with the structural formula: Method for the synthesis of triglycidyl isoeugenol from a provided solution, suspension or emulsion of isoeugenol comprising the following process steps: a) first step: synthesis of allyl isoeugenol (A-IEU) by allylation of the isoeugenol, e.g.: b) Second stage: Synthesis of rAllylisoeugenol (rA-IEU) by Claisen rearrangement, e.g.: c) Third stage: Synthesis of the glycidyl ether of rAllylisoeugenol (EPO-rA-IEU) by epoxidation of the hydroxyl group with epibromohydrin or epichlorohydrin, e.g.: d) Fourth stage: Synthesis of triglycidyl isoeugenol (3EPO-IEU) by epoxidation of the double bonds, e.g.: The method according to claim 3, characterized in that in the first stage polar solvents, preferably butanol, acetonitrile, acetone, isopropanol, water, dimethylformamide (DMF), dimethyl sulfoxide (DMSO), in particular DMSO, are used as solvents for the isoeugenol. The method according to claim 3 or 4, characterized in that in the first stage allyl halides, allyl ethyl carbonate, allyl methyl carbonate, diallyl carbonate, allyl alcohol or allyl trimethylammonium chloride, preferably allyl bromide or allyl chloride, in particular allyl bromide, can be used or is used as the allylation reagent(s). Method according to claim 3, 4 or 5, characterized in that in the first stage potassium iodide, alkaline solutions, potassium carbonate, tripropylamine, sodium sulfite, preferably alkaline solutions, in particular sodium hydroxide, are used as reagent(s). Method according to claim 3, 4, 5 or 6, characterized in that in the first stage stirring takes place at 0 °C to 100 °C, preferably at 20 °C to 70 °C, particularly at 25 °C to 40 °C, for 1 h to 24 h, preferably 2 h to 6 h, particularly 4 h. Method according to claim 3, 4, 5, 6 or 7, characterized in that the reaction of the first stage takes place under protective gas. Method according to claim 3 and at least one of the following claims, characterized in that the Claisen rearrangement in the second stage is carried out at a temperature of 80 °C to 250 °C, preferably 170 °C to 225 °C, in particular 200 °C and a reaction time of 0.5 h to 24 h, preferably 2 h to 10 h, in particular 5 h. The method according to claim 9, characterized in that in the second stage the intermediate product A-IEU is stirred under protective gas, wherein DMF, xylenes, toluene can be used as solvents, but preferably no solvent is used. The method according to claim 9 or 10, characterized in that zinc chloride, bismuth triflate and / or ethylene glycol can be added as catalysts in the second stage, but preferably no catalyst is used. Method according to claim 9, 10 or 11, characterized in that the second stage can be carried out in a microwave and / or a pressure reactor, but preferably this device is not used. The method according to claim 3 and at least one of the following claims, characterized in that in the third stage (non)polar solvents, preferably tert-butanol, methyl ethyl ketone (MEK), benzene, dimethylformamide (DMF), acetonitrile, THF, dioxane and particularly preferably no solvent are used for the intermediate product rA-IEU. The method according to claim 13, characterized in that in the third stage the intermediate product rA-IEU is mixed with epibromohydrin or epichlorohydrin, preferably with epichlorohydrin and a phase transfer catalyst, and stirred at 0 °C to 100 °C, preferably at 70 °C to 90 °C, particularly at 80 °C for 1 to 24 h, preferably 1 h to 6 h, particularly 3 h. The method according to claim 14, characterized in that in the third stage sodium hydroxide (NaOH) and a phase transfer catalyst are dissolved in water and added dropwise to the mixture. The method according to claim 15, characterized in that the phase transfer catalyst is, for example, tetrabutylammonium bromide, benzyltriethylammonium chloride, hexadecyltrimethylammonium bromide, 18-crown-6, potassium tert-butoxide, tetraethylammonium bromide, preferably tetrabutylammonium bromide (TBAB). The method according to claim 13, 14, 15 or 16, characterized in that, after completion of the reaction of the third stage, the reaction mixture is extracted, e.g. with ethyl acetate, washed, e.g. with distilled water and saturated NaCl solution, the organic layer is separated and the intermediate is dried to obtain the intermediate product EPO-rA-IEU. The method according to claim 3, characterized in that in the fourth stage peracids, Oxone®, potassium peroxomonosulfate, hydrogen peroxide, tert-butyl hydroperoxide, carbamide peroxide, trimethylsilyl peroxide, preferably chloroperbenzoic acid (mCPBA), Oxone®, potassium peroxomonosulfate, in particular Oxone® are used as epoxidizing reagents. The method according to claim 18, characterized in that in the fourth stage a solvent mixture of water, a polar solvent and a ketone, preferably water, methanol or ethyl acetate or DMSO with acetone or MEK, in particular a water, ethyl acetate, acetone mixture, is used as a solvent. Method according to claim 19, characterized in that in the fourth stage the solution is stirred for 1 h to 30 h, preferably 3 h to 28 h, in particular 24 h at -40 °C to 40 °C, preferably at -25 °C to 25 °C, in particular at 0 °C to 25 °C. The method according to claim 19 or 20, characterized in that the by-product diglycidyl allyl isoeugenol (2EPO-rA-IEU) is formed in the fourth stage.

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