Method for preparing dicarboxylic ester from renewable alpha-angelica lactone

Abstract

The invention discloses a method for preparing dicarboxylic acid ester from renewable alpha-angelica lactone. The preparation method comprises the following specific steps: step 1, in an organic solvent system, alpha-angelica lactone and acrylate are subjected to a Michael addition reaction under base catalysis; and 2, carrying out ring opening / hydrodeoxygenation reaction on the addition product under the action of a metal / acid catalyst to prepare the dicarboxylic ester. The invention provides a biomass-based method for preparing dicarboxylic ester, the whole preparation process is simple and convenient to operate, green and environment-friendly, and the method has application prospects in the fields of bio-based polymer new materials, biomass-based plasticizers and the like.

Description

Technical Field

[0001] The invention relates to the technical field of organic synthesis of compounds, and in particular to a method for preparing dicarboxylic acid esters from renewable alpha-angelica lactone. Background Art

[0002] Polymers, as a class of high-molecular materials formed by covalently linked repeating units, play a vital role in the development of modern society. From plastics, rubbers to fibers and high-performance composite materials, polymers are widely used in industry, agriculture, medicine and daily life. Most high-molecular materials come from petroleum, and because they cannot be degraded, they usually cause serious water pollution and land pollution. Due to environmental damage and the increasing depletion of oil reserves, research and development of biodegradable high-molecular materials based on biomass as raw materials have attracted much attention. Biomass resources are renewable resources with a wide range of sources and large reserves. Biomass chemicals can be obtained from them, which has good application prospects. Dicarboxylic acids are an important class of organic compounds with two carboxyl groups (-COOH) in their molecular structure. As key monomers or additives, they play an important role in the synthesis and performance regulation of various polymers, especially in the fields of polyesters, polyamides and high-performance composite materials.

[0003] At present, important industrial monomers such as dicarboxylic acids (oxalic acid, malonic acid, succinic acid, sebacic acid, adipic acid) are mainly derived from non-renewable petroleum resources. Due to the energy characteristics of my country's oil-poor state, from a strategic point of view, petrochemical processes are not conducive to my country's energy security. Therefore, the development of a renewable biomass supply system to produce aromatic polycarboxylic acids has attracted much attention. Compared with the preparation of dicarboxylic acids based on petroleum, the preparation of diacid carboxylic acids from biomass is less studied and needs further research. Angelica lactone is a naturally occurring molecule that shows three isomeric forms -α, -β, and -γ, which differ in the position of the carbon-carbon double bond. α-Angelica lactone can be found in grapes, soybeans, and soy beans. It has a sweet, coconut and vanilla flavor with hay and coumarin-like nuances; it is used in aromatic and dairy formulations with coconut, vanilla, molasses, coumarin, cream, milk, nuts, and tobacco flavors. In recent years, the modification of biomass derivatives has been a very promising research field in both academia and industry. In this sense, many new methods and products have been developed, usually involving levulinic acid as a starting material or intermediate. However, there are no reports on the preparation of dicarboxylic acids using angelica lactone as a starting material. Summary of the invention

[0004] The purpose of the present invention is to provide a method for preparing dicarboxylic acid esters from renewable alpha-angelica lactone, which has simple steps and high yield and can prepare symmetrical, green and high-yield dicarboxylic acid esters.

[0005] To achieve the above object, the technical solution adopted by the present invention is as follows: A method for preparing dicarboxylic acid esters from renewable α-angelica lactone comprises the following steps:

[0006] In the first step, in an organic solvent system, the compound α-angelica lactone of formula 1 undergoes Michael addition reaction with the compound acrylate of formula 2 under the action of a basic catalyst to generate a compound of formula 3; the reaction temperature is between 0-100° C., and the reaction time is between 10-20 hours;

[0007]

[0008] The second step is to dissolve the compound of formula 3 in an alcohol solvent, and to undergo a ring-opening / hydrogenation deoxygenation reaction under the catalysis of a metal / acid catalyst to prepare a dicarboxylic acid ester of the compound of formula 5; the reaction temperature is between 100-300° C., the reaction time is between 4-12 hours, and the hydrogen pressure is between 1-6 MPa;

[0009]

[0010] In the formula, R is selected from one of C1-C10 alkyl, phenyl and benzyl; R 1 One selected from C1-C10 alkyl, phenyl and benzyl.

[0011] Preferably, in the first step, the alkaline catalyst is selected from one or more of the following catalysts: homogeneous catalyst: 4-dimethylaminopyridine (DMAP), triethylamine (Et3N), 1,5,7-triazabicyclo[4.4.0]decene-5-ene (TBD), N,N-diisopropylethylamine (DIPEA), 1,8-diazabispiro[5.4.0]undec-7-ene (DBU), 1,4-diazabicyclo[2.2.2]octane (DABCO), sodium methoxide (NaOCH3), sodium ethoxide (NaOEt), sodium tert-butoxide (NaO t Bu), sodium n-butoxide (NaO n Bu), potassium methoxide (KOCH3), potassium ethoxide (KOEt), potassium tert-butoxide (KO t Bu), potassium n-butoxide (KO n Bu), lithium methoxide (LiOCH3), lithium ethoxide (LiOEt), lithium tert-butoxide (LiO t Bu), lithium n-butoxide (LiO n Bu), diethylamine (Et2NH), aniline (C6H5NH2), diethylmethylamine (Et2NMe), diisopropylamine ( i Pr2NH), diisopropylethylamine ( iPr2NEt), hexamethylenetetramine (HMTA), piperidine (Pip); heterogeneous catalysts: Amberlyst A26, Amberlyst A21, KF / Al2O3, Mg-Al hydrotalcite, Cs2O / Al2O3, IRA-402, sodium hydroxide (NaOH), potassium hydroxide (KOH), lithium hydroxide (LiOH), cesium hydroxide (CsOH), calcium oxide (CaO), magnesium oxide (MgO), zinc oxide (ZnO), aluminum oxide (Al2O3), cerium oxide (CeO2), titanium oxide (TiO2); wherein, for homogeneous catalysts, the amount is calculated by molar ratio, and the molar ratio of the homogeneous catalyst to α-angelica lactone is 0.01 to 20; for heterogeneous catalysts, the amount is calculated by mass ratio, and the mass ratio of the heterogeneous catalyst to α-angelica lactone is 0.01 to 20.

[0012] Preferably, in the first step, the organic solvent is selected from one or more of dichloromethane (DCM), dichloroethane (DCE), tetrahydrofuran (THF), 2-methyltetrahydrofuran (2-THF), 1,4-dioxane (1,4-Dioxane), n-hexane (Hexane), cyclohexane (Cyclohexane), n-octane (Cyclooctane), ethyl acetate (EA), cyclohexanone (CYH), toluene (PhMe), dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), acetone (ACE), ethanol (EtOH), isopropanol (IPA), N-methylpyrrolidone (NMP), propylene carbonate (PC), dimethyl carbonate (DMC), methanol (MeOH), and tert-butanol, and the substrate concentration range is 0.5-1 mol / L.

[0013] Preferably, in the first step, the reaction temperature of the Michael addition reaction is between 0-10°C and the reaction time is between 13-16h.

[0014] Preferably, in the second step, the metal / acidic catalyst can be a physical mixture of a metal catalyst and an acidic catalyst, the metal catalyst is selected from one of Raney Ni, Raney Cu, Raney Co, Pt / C, Pd / C, Ru / C, Ir / C, Rh / C, Co / C, Ni / C, and Cu / C, and the acidic catalyst is selected from one of phosphotungstic acid (HPW), silicotungstic acid (HSiW), H-Beta, HY, H-MOR, H-ZSM5, and MCM-41; the ratio of the amount of the metal catalyst to the mass of the compound of formula 3 is between 0.01 and 1, and the ratio of the amount of the acidic catalyst to the mass of the compound of formula 3 is between 0.01 and 1;

[0015] The metal / acid catalyst can also be a supported catalyst, with one of H-Beta, HY, H-MOR, H-ZSM5, and MCM-41 as the carrier, the supported metal being one or more of Ni, Co, Cu, Pd, Pt, Ru, Rh, and Ir, and the metal mass loading being 0.01-60%; wherein the ratio of the amount of the supported catalyst to the mass of the compound of formula 3 is between 0.01 and 1.

[0016] Preferably, in the second step, the alcohol solvent is one of methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, octanol and nonanol, and the substrate concentration range is 0.01-1 mol / L.

[0017] Preferably, in the second step, the reaction temperature of the ring-opening / hydrodeoxygenation reaction is between 180-220° C., the reaction time is between 8-12 h, and the hydrogen pressure is 2 MPa.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. The present invention can completely realize the high-yield preparation of dicarboxylic acid esters from biomass derivatives α-angelica lactone, ethyl acrylate / methyl acrylate and other acrylic acid ester compounds through a two-step method. Dicarboxylic acid esters are bio-based carboxylic acid ester compounds that can be used to prepare polyesters and have broad prospects;

[0020] 2. The entire route uses biomass as raw material, which is a new green route that does not produce harmful substances. The catalyst can be recycled. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 .MS spectrum of the addition product 3a obtained in Example 71.

[0022] Figure 2 .GC spectrum of the addition product 3a obtained in Example 71.

[0023] Figure 3 Example 71 Preparation of the addition product 3a 1 H NMR spectrum.

[0024] Figure 4 Example 71 Preparation of the addition product 3a 13 C NMR spectrum.

[0025] Figure 5 .MS spectrum of the addition product 3b obtained in Example 149.

[0026] Figure 6 .GC spectrum of the addition product 3b obtained in Example 149.

[0027] Figure 7Example 149 The addition product 3b obtained 1 H NMR spectrum.

[0028] Figure 8 Example 149 The addition product 3b obtained 13 C NMR spectrum.

[0029] Fig. 9 .MS spectrum of the hydrogenation product 5a obtained in Example 192.

[0030] Fig.10 .GC spectrum of the hydrogenation product 5a obtained in Example 192.

[0031] Fig.11 Example 192 Hydrogenated product 5a 1 H NMR spectrum.

[0032] Fig.12 Example 192 Hydrogenated product 5a 13 C NMR spectrum.

[0033] Fig.13 .MS spectrum of the hydrogenation product 5b obtained in Example 235.

[0034] Fig.14 .GC spectrum of the hydrogenation product 5b obtained in Example 235.

[0035] Fig.15 Example 235 Hydrogenated product 5b 1 H NMR spectrum.

[0036] Fig.16 Example 235 Hydrogenated product 5b 13 C NMR spectrum.

[0037] Fig.17 Example 235 obtained hydrogenation product 5b polymerization product 1 H NMR spectrum. DETAILED DESCRIPTION

[0038] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0039]

[0040] Example 1-158

[0041] The biomass platform compound α-angelica lactone and ethyl acrylate / methyl acrylate undergo Michael addition reaction under alkaline conditions to generate addition products (effects of catalyst, temperature, solvent, and time)

[0042] Add α-angelica lactone (1mmol, 0.981g), ethyl acrylate (1.2mmol, 0.13mL) / methyl acrylate (1.2mmol, 0.102mL) into a 4mL sample bottle, stir in an ice-water bath for 5min, then add 0.1mmol of homogeneous alkaline catalyst / 10wt% of heterogeneous alkaline catalyst, and react at 0-100℃ for 12-16h.

[0043] Table 1. Effects of catalyst, temperature, solvent and time on the Michael addition reaction of angelica lactone and ethyl acrylate

[0044]

[0045]

[0046]

[0047] From the results in Table 1, it can be seen that the reaction has a good performance in the homogeneous catalysts TBD and DBU, and the reaction yield is high. Among them, the catalytic performance of DBU is the best, and the catalytic performance of the heterogeneous catalyst is poor. Considering the safety of the experiment, the recyclable heterogeneous catalyst is not selected to continue to increase the temperature to screen the optimal conditions; In addition, from Table 1, it can be seen that the temperature has a great influence on the reaction. At 0°C, the yield of the addition product 3a can reach 89%, but considering the harshness of the reaction temperature and the impact on subsequent treatment, 10°C is selected as the temperature condition for the reaction. Through screening of different solvents, it was found that dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), N-methylpyrrolidone (NMP) and propylene carbonate (PC) have relatively good effects on the reaction, but considering the difficulty of subsequent treatment of the solvent and from the perspective of environmental greenness, N,N-dimethylformamide (DMF) was selected as the solvent. Through screening of different reaction times, it was found that extending the time would increase the yield of the addition product 3a. The yield of the dimerization product was 83% after 13 hours of reaction, and the yield could reach 88% after 14 hours of reaction. Therefore, 14 hours was selected as the reaction time for this reaction.

[0048] Table 2. Effects of catalyst, temperature, solvent and time on the Michael addition reaction of angelica lactone and methyl acrylate

[0049]

[0050]

[0051]

[0052] From the results in Table 2, it can be seen that the reaction has a good performance in the homogeneous catalysts TBD and DBU, and the reaction yield is high. Among them, the catalytic performance of DBU is the best, and the catalytic performance of the heterogeneous catalyst is poor. Considering the economic efficiency of production, the recyclable heterogeneous catalyst is not selected to continue to increase the temperature to screen the optimal conditions; it can be seen from Table 2 that the temperature has a great influence on the reaction. The lower the temperature, the higher the yield of the addition product 3b. However, when the temperature reaches 10°C, the temperature continues to be lowered, and the yield of the addition product 3b no longer changes. Therefore, 10°C is selected as the temperature condition for the reaction. Through screening of different solvents, it was found that dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), N-methylpyrrolidone (NMP) and propylene carbonate (PC) have relatively good effects on the reaction, but considering the difficulty of subsequent treatment of the solvent and from the perspective of environmental greenness, N,N-dimethylformamide (DMF) was selected as the solvent. Through screening of different reaction times, it was found that extending the time would increase the yield of the addition product 3a. The yield of the dimerization product was 85% after 13 hours of reaction, and the yield could reach 90% after 14 hours of reaction. Therefore, 14 hours was selected as the reaction time for this reaction.

[0053] The MS spectrum of the addition product 3a obtained in Example 71 is as follows: Figure 1 As shown in the figure, it can be seen that the maximum mass-to-charge ratio of the molecular ion peak of the substance is m / z=198, while the relative molecular mass of α-angelica lactone is 98, the relative molecular mass of ethyl acrylate is 100, and the relative molecular weight of the addition product 3a is 198. Therefore, this product may be the target addition product 3a, and nuclear magnetic resonance will be needed for auxiliary verification in the future.

[0054] The GC spectrum of the addition product 3a obtained in Example 71 is as follows: Figure 2 As shown. The gas chromatograph set the injection port temperature to 270°C, the initial column box temperature to 40°C, the heating rate to 15°C / min, the temperature to 280°C and maintained for 5 min. The substance that appeared at 9.7 min in the GC graph was the internal standard n-tridecane, and the substance that appeared at 11.7 min was the addition product 3a.

[0055] Example 71 The addition product 3a obtained 1 H NMR spectrum Figure 3 shown. 1 H NMR (600MHz, Chloroform-d) δ7.32 (dq, J=5.5, 2.5Hz, 1H), 6.00 (d, J=5.6, 2.4Hz, 1H), 4.09 (q, J=7 .1,2.2Hz,2H),2.42–2.20(m,2H),2.13(dt,2H),1.47(d,J=2.4Hz,3H),1.22(t,J=7.0,2.3Hz,3H).

[0056] Example 71 The addition product 3a obtained 13 C NMR spectrum Figure 4 shown. 13 C NMR (151MHz, Chloroform-d) δ172.63,172.17,159.70,120.91,87.86,60.74,32.68,28.39,24.21,14.14.

[0057] The MS spectrum of the addition product 3b obtained in Example 149 is as follows: Figure 5 As shown in the figure, it can be seen that the maximum mass-to-charge ratio of the molecular ion peak of the substance is m / z=184, while the relative molecular mass of α-angelica lactone is 98, the relative molecular mass of methyl acrylate is 86, and the relative molecular weight of the addition product 3b is 184, so the product may be the target addition product 3b.

[0058] The GC spectrum of the addition product 3b obtained in Example 149 is as follows: Figure 6 As shown. The gas chromatograph set the injection port temperature to 270°C, the initial column box temperature to 40°C, the heating rate to 15°C / min, the temperature to 280°C and maintained for 5 min. The substance that appeared at 9.7 min in the GC graph was the internal standard n-tridecane, and the substance that appeared at 11.3 min was the addition product 3b.

[0059] Example 149 The addition product 3b obtained 1 H NMR spectrum Figure 7 shown. 1 H NMR (600MHz, Chloroform-d) δ7.30 (dq, J = 5.6Hz, 1H), 5.95 (d, J = 5.7Hz, 1H), 3.58 (s, 3H), 2.46–2.15 (m, 2H), 2.16–1.89 (m, 2H), 1.42 (d, 3H).

[0060] Example 149 The addition product 3b obtained 13 C NMR spectrum Figure 8 shown. 13 C NMR (151MHz, Chloroform-d) δ172.97,172.10,159.74,120.82,87.79,51.76,32.64,28.11,24.10.

[0061] Examples 159-245

[0062]

[0063] The addition product is subjected to a ring-opening / hydrogenation deoxygenation reaction to generate a dicarboxylic acid ester under the catalysis of a metal catalyst / acid catalyst; the metal catalyst is selected from Raney Ni, Raney Cu, Raney Co, Pt / C, Pd / C, Ru / C, Ir / C, Rh / C, Co / C, Ni / C, Cu / C, and Fe / C; the acid catalyst is selected from phosphotungstic acid (HPW), silicotungstic acid (HSiW), H-Beta, HY, H-MOR, H-ZSM5, MCM-41, H-Beta, HY, H-MOR, H-ZSM5, and MCM-41; the metal / acid catalyst can also be a supported catalyst: one of H-Beta, HY, H-MOR, H-ZSM5, and MCM-41 is used as a carrier, and the supported metal is Ni, Co, Cu, Pd, Pt, Ru, Rh, or Ir.

[0064] In a 30mL reactor, add the addition product 3a (0.198g, 1mmol) of ethyl acrylate / the addition product 3b (0.184g, 1mmol) of methyl acrylate and 4.5mL of ethanol / methanol, then add 40mg of catalyst (active metal loading 5wt%) / 40mg of acidic molecular sieve catalyst, react for a period of time at a certain temperature and 2MPa hydrogen pressure to obtain dicarboxylic acid ester.

[0065] Table 3. Effects of catalyst, time and temperature on hydrogenation reaction (products of ethyl acrylate hydrogenation)

[0066]

[0067]

[0068]

[0069] From the results in Table 3, it can be seen that the hydrogenation capabilities of different metal catalysts are different, among which Pd / C has the best ability, and Pt / C, Ru / C, and Rh / C have similar hydrogenation capabilities. Considering their prices, the catalyst can be used to achieve industrial production. The molecular sieve catalysts HPW, H-Beta, and HY have similar effects. Considering the subsequent cycle experiments, the homogeneous HPW is selected. Considering that the metal loading on the molecular sieve has little effect on the reaction, the hydrogenation catalyst and the molecular sieve catalyst are mixed for the experiment. Then the temperature when using ethanol as a solvent for the hydrogenation reaction is screened, and it can be concluded that the yield is the same at 180℃, 200℃, and 220℃. In order to ensure the complete conversion of the raw materials, 200℃ is selected as the conditional temperature of the reaction; the reaction time is screened for the reaction, and it is found that the yield of the reaction is the same at 8h, 10h, and 12h. In order to ensure the complete conversion of the raw materials, 10h is selected as the conditional time of the reaction, and finally the optimal conditions for the hydrogenation reaction are obtained.

[0070] In practical applications, the service life of the catalyst needs to be examined. Therefore, ethanol was used as the solvent and HPW as the catalyst. The reaction was carried out at 200°C for 10 hours to study the recycling of Pd / C. After the first reaction, the reaction was cooled to room temperature, an internal standard (tridecane) was added, and the yield was calculated by GC. Table 4 shows that the yield did not decrease significantly after the fourth reaction (the third cycle), so the Pd / C catalyst can be recycled 3 times.

[0071] Table 4. Pd / C cycle experiment

[0072]

[0073] Table 5. Effects of catalyst, time, temperature and solvent on hydrogenation reaction (methyl acrylate hydrogenation product)

[0074]

[0075]

[0076] From the results in Table 5, it can be seen that the hydrogenation capabilities of different metal catalysts are different, among which Pd / C has the best ability, and Pt / C, Ru / C, and Rh / C have similar hydrogenation capabilities. Considering its price, this catalyst can be used to achieve industrial production. Molecular sieve catalysts, HPW, H-Beta, and HY have similar effects. Considering the subsequent cycle experiments, the homogeneous HPW is selected. Then the temperature when using methanol as a solvent for hydrogenation reaction is screened, and it can be concluded that the highest yield is obtained at 240°C. In order to ensure the complete conversion of the raw materials, we choose 240°C as the condition temperature of the reaction; the reaction time is screened for the reaction, and it is found that the yield of the reaction is the same for 8h, 10h, and 12h. In order to ensure the complete conversion of the raw materials, we choose 10h as the condition time of the reaction, and finally the best conditions for the hydrogenation reaction are obtained.

[0077] In practical applications, the service life of the catalyst needs to be examined. Therefore, methanol was used as the solvent and HPW as the catalyst. The reaction was carried out at 240°C for 10 hours to study the recycling of Pd / C. After the first reaction, the reaction was cooled to room temperature, an internal standard (tridecane) was added, and the yield was calculated by GC. Table 6 shows that the yield did not decrease significantly after the fifth reaction (the fourth cycle), so the Pd / C catalyst can be recycled 4 times.

[0078] Table 6. Pd / C cycle experiment

[0079]

[0080]

[0081] The MS spectrum of the hydrogenation product 5a obtained in Example 192 is as follows: Fig. 9 As shown in the figure, it can be seen that the maximum mass-to-charge ratio of the molecular ion peak of the substance is m / z=230, and the relative molecular mass of the addition product 5a is 198. After the ring-opening hydrodeoxygenation, the relative molecular weight of the hydrogenation product 5a is 230. Therefore, this product may be the target hydrogenation product 5a, and nuclear magnetic resonance is needed for auxiliary verification in the future.

[0082] The GC spectrum of the hydrogenation product 5a obtained in Example 192 is as follows: Fig.10 As shown. The gas chromatograph set the injection port temperature to 270°C, the initial column box temperature to 40°C, the heating rate to 15°C / min, the temperature to 280°C and maintained for 5 minutes. The substance that appeared at 9.7min in the GC graph was the internal standard n-tridecane, and the substance that appeared at 11.8min was the hydrogenation product 5a.

[0083] Example 192 Hydrogenated product 5a 1 H NMR spectrum Fig.11 shown. 1 H NMR (600MHz, Chloroform-d) δ4.09(q,4H),2.52–2.13(m,4H),1.84–1.55(m,1H),1.55–1.35(m,4H),1.22(t,J=7.9,7.2,3.7Hz,6H),0.87(d,3H).

[0084] Example 192 Hydrogenated product 5a 13 C NMR spectrum Fig.12 shown. 13 C NMR(151MHz,Chloroform-d)δ173.77,60.20,38.55–26.96(m),18.87,14.19.

[0085] The MS spectrum of the hydrogenation product 5b obtained in Example 235 is as follows: Fig.13 As shown in the figure, it can be seen that the maximum mass-to-charge ratio of the molecular ion peak of the substance is m / z=202, and the relative molecular mass of the addition product 5b is 184. After the ring-opening hydrogenation and deoxygenation, the relative molecular weight of the hydrogenation product 5b is 202, so this product may be the target hydrogenation product 5b.

[0086] The GC spectrum of the hydrogenation product 5b obtained in Example 235 is as follows: Fig.14As shown. The gas chromatograph set the injection port temperature to 270°C, the initial column box temperature to 40°C, the heating rate to 15°C / min, the temperature to 280°C and maintained for 5 minutes. The substance that appeared at 9.7min in the GC graph was the internal standard n-tridecane, and the substance that appeared at 10.8min was the hydrogenation product 5b.

[0087] Example 235 Hydrogenated product 5b 1 H NMR spectrum Fig.15 shown. 1 H NMR (600MHz, Chloroform-d) δ3.55 (s, 6H), 2.38–2.02 (m, 4H), 1.57 (dt, J = 7.8, 7.2Hz, 2H), 1.36 (dt, J = 14.4, 6.9Hz, 3H), 0.79 (d, J = 5.3Hz, 3H).

[0088] Example 235 Hydrogenated product 5b 13 C NMR spectrum Fig.16 shown. 13 C NMR (151MHz, Chloroform-d) δ174.00,51.31,31.85,31.50,31.36,18.73.

[0089] Application example: polymer preparation

[0090]

[0091] Take dimethyl terephthalate DMT (120g, 0.62mol, 1.0eq, bp 200℃), 1,4-butanediol (160.2g, 157.5mL, 1.78mol, 2.5eq, bp 230℃), monomer 5b (54.54g, 0.27mol), zinc acetate (0.049g, 0.03mol%of DMT), antimony trioxide (0.077g, 0.03mol%of DMT), tetrabutyl titanate (0.075g, 0.025mol%of DMT, dissolved in 2mL of 1,4-butanediol, add 1mL during ester exchange) and add them into the polymerization reactor, replace with N2 twice, and open the valve to allow methanol to flow out under normal pressure after pressure is generated in the reactor.

[0092] At the beginning of the transesterification reaction, the kettle temperature is adjusted to 195°C (the temperature inside the kettle is 180°C. This temperature is set because if the temperature is too high, butanediol in the kettle or tetrahydrofuran by-product may be generated due to excessive temperature). When the top temperature of the tower rises to about 70°C, methanol begins to distill out. When there is no distillate, the transesterification reaction is completed. The total distillate is 65mL (the theoretical methanol distillation volume is 72mL, and the actual distillation volume only needs to reach 90% of the theoretical amount).

[0093] After the ester exchange is completed, 1 mL of the prepared tetrabutyl titanate solution is added, the temperature of the reactor is adjusted to 255°C, the vacuum pump is turned on and slowly vacuumed (reduced by 20 kPa every 15 minutes), after the vacuum environment is established, the polycondensation reaction is started, the speed is 100 rpm and the torque rises to 2.8-3.0 Nm, the reaction is completed, N2 is filled to normal pressure, and the material is discharged. The intrinsic viscosity of the polymer is measured to be 0.6222 dL / g.

[0094] 1 H NMR spectrum Fig.17 shown. 1H NMR(400MHz,Chloroform-d)δ8.13(s,4H),4.63–4.40(m,4H),4.35–4.14(m,2H),2.44(td,J=9.7,5.9Hz,2H) ,2.04(s,3H),1.90(dt,J=8.7,4.4Hz,2H),1.81–1.59(m,1H),1.49(d,J=15.3Hz,1H),0.90(d,J=5.5Hz,1H).

[0095] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any modifications, equivalent substitutions and improvements made by any technician familiar with the technical field within the technical scope disclosed by the present invention and within the spirit and principle of the present invention should be covered by the protection scope of the present invention.

Claims

1. A method for preparing dicarboxylic acid esters from renewable α-angelica lactone, characterized in that: The following steps are involved: In the first step, in an organic solvent system, the compound α-angelica lactone of formula 1 undergoes Michael addition reaction with the compound acrylate of formula 2 under the action of a basic catalyst to generate a compound of formula 3; the reaction temperature is between 0-100° C., and the reaction time is between 10-20 hours; In the second step, the compound of formula 3 is dissolved in an alcohol solvent, and a ring-opening / hydrodeoxygenation reaction is carried out under the catalysis of a metal catalyst and an acid catalyst to prepare a dicarboxylic acid ester of the compound of formula 5; the reaction temperature is between 100-300° C., the reaction time is between 4-12 hours, and the hydrogen pressure is between 1-6 MPa; In the formula, R is selected from one of C1-C10 alkyl, phenyl and benzyl; R 1 One selected from C1-C10 alkyl, phenyl and benzyl.

2. A method for preparing dicarboxylic acid esters from renewable α-angelica lactone according to claim 1, characterized in that: In the first step, the alkaline catalyst is selected from one or more of the following catalysts: homogeneous catalyst: 4-dimethylaminopyridine, triethylamine, 1,5,7-triazabicyclo[4.4.0]decene-5-ene, N,N-diisopropylethylamine, 1,8-diazabispiro[5.4.0]undec-7-ene, 1,4-diazabicyclo[2.2.2]octane, sodium methoxide, sodium ethoxide, sodium tert-butoxide, sodium n-butoxide, potassium methoxide, potassium ethoxide, potassium tert-butoxide, potassium n-butoxide, lithium methoxide, lithium ethoxide, lithium tert-butoxide, lithium n-butoxide, diethylamine, aniline, diethylmethylamine, diisopropylamine, diisopropylethylamine, hexamethylenetetramine, piperidine; heterogeneous catalyst: Amberlyst A26, Amberlyst A21, KF / Al2O3, Mg-Al hydrotalcite, Cs2O / Al2O3, IRA-402, sodium hydroxide, potassium hydroxide, lithium hydroxide, cesium hydroxide, calcium oxide, magnesium oxide, zinc oxide, aluminum oxide, cerium oxide, titanium oxide; wherein, for homogeneous catalysts, their amounts are calculated by molar ratio, and the molar ratio of the homogeneous catalyst to α-angelica lactone is 0.01 to 20; for heterogeneous catalysts, their amounts are calculated by mass ratio, and the mass ratio of the heterogeneous catalyst to α-angelica lactone is 0.01 to 20.

3. The method for preparing dicarboxylic acid esters from renewable α-angelica lactone according to claim 1, characterized in that: In the first step, the organic solvent is selected from one or more of dichloromethane, dichloroethane, tetrahydrofuran, 2-methyltetrahydrofuran, 1,4-dioxane, n-hexane, cyclohexane, n-octane, ethyl acetate, cyclohexanone, toluene, dimethyl sulfoxide, N,N-dimethylformamide, acetone, ethanol, isopropanol, N-methylpyrrolidone, propylene carbonate, dimethyl carbonate, methanol, and tert-butanol, and the substrate concentration range is 0.5-1 mol / L.

4. The method for preparing dicarboxylic acid esters from renewable α-angelica lactone according to claim 1, characterized in that: In the first step, the reaction temperature of the Michael addition reaction is between 0-10° C., and the reaction time is between 13-16 h.

5. The method for preparing dicarboxylic acid esters from renewable α-angelica lactone according to claim 1, characterized in that: In the second step, the metal / acidic catalyst can be a physical mixture of a metal catalyst and an acidic catalyst, the metal catalyst is selected from one of Raney Ni, Raney Cu, Raney Co, Pt / C, Pd / C, Ru / C, Ir / C, Rh / C, Co / C, Ni / C, and Cu / C, and the acidic catalyst is selected from one of phosphotungstic acid, silicotungstic acid, H-Beta, HY, H-MOR, H-ZSM5, and MCM-41; the ratio of the amount of the metal catalyst to the mass of the compound of formula 3 is between 0.01 and 1, and the ratio of the amount of the acidic catalyst to the mass of the compound of formula 3 is between 0.01 and 1; The metal / acid catalyst can also be a supported catalyst, with one of H-Beta, HY, H-MOR, H-ZSM5, and MCM-41 as the carrier, the supported metal being one or more of Ni, Co, Cu, Pd, Pt, Ru, Rh, and Ir, and the metal mass loading being 0.01-60%; wherein the ratio of the amount of the supported catalyst to the mass of the compound of formula 3 is between 0.01 and 1.

6. The method for preparing dicarboxylic acid esters from renewable α-angelica lactone according to claim 1, characterized in that: In the second step, the alcohol solvent is one of methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, octanol and nonanol, and the substrate concentration range is 0.01-1 mol / L.

7. The method for preparing dicarboxylic acid esters from renewable α-angelica lactone according to claim 1, characterized in that: In the second step, the reaction temperature of the ring-opening / hydrodeoxygenation reaction is between 180-220° C., the reaction time is between 8-12 h, and the hydrogen pressure is 2 MPa.

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