Cup[4]arene derivatives and their application in green synthesis of cyclic carbonates from co2

Abstract

The application belongs to the field of catalytic organic synthesis, and particularly relates to calix[4]arene derivatives and application thereof in green synthesis of cyclic carbonates from CO2. In the application, epoxide is used as a raw material, a hydrogen bond donor calix[4]arene derivative is used as a catalyst, a quaternary ammonium salt is used as a cocatalyst, and a solvent is used in a ring addition reaction with CO2 at normal temperature and pressure. After the reaction, the product is obtained by extraction, separation, concentration and silica gel column chromatography. The hydrogen bond donor calix[4]arene derivative has the advantages of mild catalytic synthesis process, high catalytic efficiency, high yield at normal temperature and pressure, and wide application prospect.

Description

Technical Field

[0001] This invention belongs to the field of catalytic organic synthesis technology, and particularly relates to a green catalytic method for the cycloaddition reaction of CO2 with epoxides and its catalyst. Background Technology

[0002] Cyclic carbonates are versatile compounds with wide applications in lithium-ion batteries, pharmaceutical manufacturing, and many fine chemicals. The synthesis of cyclic carbonates via cycloaddition reactions of CO2 and epoxides is considered one of the most promising CO2 conversion routes because it is 100% atom-economical, non-toxic, and a more economical CO2 utilization technology. Therefore, developing an efficient and selective synthetic method is of great significance.

[0003] Hydrogen-bonded donor catalysts are an important research direction in the field of organic synthesis. They play a crucial role in catalytic reactions through hydrogen-bonded interactions. The design and application of such catalysts provide new ideas and tools for organic synthesis, offering advantages such as mild reaction conditions, high catalytic efficiency, and no metal residues.

[0004] Epoxides are a class of highly reactive compounds with cyclic structures and active oxygen atoms, readily undergoing ring-opening reactions to generate various products. This reactivity of epoxides can be utilized to synthesize cyclic carbonates. Introducing hydrogen bond donors into the reaction system polarizes the CO bond between epoxides and CO2 through hydrogen bonding, promoting bond breaking and achieving highly efficient catalytic conversion of epoxides and CO2. This makes the synthesis of cyclic carbonates more efficient and selective, and can be carried out under mild conditions, reducing environmental impact and demonstrating better sustainability.

[0005] In the existing technology, supramolecular catalysts are used relatively little in the cycloaddition reaction of CO2 and epoxides, and the reaction conditions are relatively harsh, usually requiring high temperature and / or high pressure. Therefore, it is necessary to find new catalysts to efficiently catalyze this reaction under relatively mild conditions. Summary of the Invention

[0006] The technical problem solved by this invention is: in order to overcome the problems of low activity, poor selectivity and harsh conditions of the cycloaddition reaction of CO2 and epoxide in the prior art, a green method for synthesizing cyclic carbonates by cycloaddition reaction of CO2 and epoxide catalyzed by hydrogen bond donor calix[4] aromatic derivatives at room temperature and pressure is provided.

[0007] The technical solution adopted by the present invention to solve its technical problem is: a hydrogen bond donor calix[4] aromatic derivative, the structural formula of which is structural formula I or structural formula II or structural formula III or structural formula IV:

[0008]

[0009] R = C3 ~ C 12 saturated hydrocarbons.

[0010] A method for catalytic cycloaddition of CO2 and an epoxide, comprising the following steps:

[0011] (1) Under normal pressure, using epoxide as raw material, hydrogen bond donor cup [4] aromatic derivative as catalyst, and quaternary ammonium salt as co-catalyst, cycloaddition reaction is carried out in the presence of solvent. The reaction temperature is 25-100℃ and the reaction time is 6-48 hours.

[0012] (2) After the reaction in step (1) is completed, the product is extracted with dichloromethane, separated by column chromatography with ethyl acetate and petroleum ether, and purified to obtain the product.

[0013] The epoxide is styrene oxide, glycidyl phenyl ether, or a substituted styrene oxide.

[0014] Furthermore, the substituted styrene oxide is a styrene oxide in which the hydrogen atoms on the benzene ring are replaced by substituents, and the substituents are one of fluorine, chlorine, bromine, nitro, trifluoromethyl, or methyl.

[0015]

[0016] Specifically, the R in the epoxide structural formula is C6H5,C6H5OCH2,4-Cl-C6H4,4-Br-C6H4,4-F-C6H4,4-CH3-C6H4,4-NO2-C6H4,4-CF3-C6H4,2-Cl-C6H4,3-Cl-C6H4,3-Cl-4-Cl-C6H3.

[0017] The amount of the hydrogen bond donor cup[4] aromatic derivative is 3 to 10% of the molar amount of the epoxide; the amount of the quaternary ammonium salt is 5 to 15% of the molar amount of the epoxide; the solvent is water, dimethyl carbonate, polyethylene glycol 200, methanol or ethanol.

[0018] The quaternary ammonium salt is tetrabutylammonium iodide or tetrabutylammonium bromide.

[0019] Preferably, the catalyst is The catalyst dosage is 5 mol% of the epoxide; the quaternary ammonium salt is tetrabutylammonium iodide, and the tetrabutylammonium iodide dosage is 10 mol% of the epoxide; the reaction temperature is 25–100 °C, with the most preferred temperature being 40 °C; the optimal reaction time is 16 hours; and the solvent is most preferably water.

[0020] The beneficial effects of this invention are:

[0021] (1) The hydrogen bond donor cup [4] aromatic derivative provided by the present invention can effectively utilize the non-covalent interaction of supramolecular catalysis to achieve the cycloaddition reaction of CO2 and epoxide under mild conditions, and has the advantages of mild synthesis process conditions, no need to separate intermediates, high catalytic efficiency and broad industrial prospects.

[0022] (2) By functionalizing the calixarene, the modification is carried out directly on the upper edge, which is a breakthrough compared with the conventional method of modifying the lower edge. This will greatly enrich the types of chemical modifications of calixarene and make full use of the advantages of the calixarene cavity and the substrate inclusion, so as to give full play to the selective recognition function of the cavity. Attached Figure Description

[0023] Figure 1 The mechanism model diagram of the catalytic oxidation of styrene with CO2 by calixar[4] aromatic derivative catalyst I is shown. Detailed Implementation

[0024] The present invention will be further described below with reference to specific embodiments. It should be understood that the embodiments are used only to illustrate the present invention and are not intended to limit the scope of the present invention.

[0025] In the examples, thin-layer chromatography (HSGF254 silica gel plate) was used to monitor the reaction progress, and column chromatography (200-300 mesh silica gel column, eluent: a mixture of ethyl acetate and petroleum ether) was used to purify the crude product. The yields given in the examples are the yields after purification by column chromatography.

[0026] 1a and 1b were synthesized by myself based on the reference (Chinese Journal of Chemistry, 2009, 27, 2031-2036).

[0027] Example 1

[0028] In this embodiment, R = n Taking Pr (n-propyl) as an example, catalysts I-1, II-1, III-1 and IV-1 are used to synthesize hydrogen bond donor calix[4] aromatic derivatives.

[0029]

[0030] The specific synthesis method is as follows:

[0031] Synthesis of hydrogen bond donor calix [4] aromatic derivative catalysts I-1, II-1, III-1 and IV-1

[0032]

[0033] 1a or 1b (200 mg, 0.32 mmol) and dimethyl squaric acid (91 mg, 0.64 mmol) were heated to reflux in 10 mL of methanol and the reaction was stopped when a large amount of yellow solid was formed. The mixture was cooled to room temperature, filtered, and the filter cake was washed with anhydrous methanol and dried to give yellow solid I-1 (173 mg, yield 64%) or II-1 (168 mg, yield 62%).

[0034] Catalyst I-1; 1 H NMR (300MHz, CDCl3) δ = 8.90 (brs, 2H), 7.21–6.90 (m, 6H), 6.15 (s, 4H), 4.44 (d, J = 11.3Hz, 10H), 4.00 (t, J = 8.1Hz, 4 H), 3.66 (t, J = 6.7Hz, 4H), 3.13 (d, J = 13.4Hz, 4H), 2.02–1.83 (m, 8H), 1.10 (t, J = 7.4Hz, 6H), 0.89 (t, J = 7.4Hz, 6H). 13 C NMR (75MHz, CDCl3) δ = 182.97, 177.89, 157.64, 153.05, 136.25, 134.46, 131.32, 129. 36,122.90,119.57,60.68,31.18,23.63,23.08,10.93,9.95.ESI-MS: m / z=843([M+H] + ).

[0035] Catalyst II-1; 1 H NMR(300MHz, CDCl3)δ=9.20(brs,2H),6.97–6.18(m,10H),4.71–4.25(m,10H),3 .94–3.66(m,8H),3.13(t,J=12.3Hz,4H),1.95–1.82(m,8H),1.08–0.89(m,12H). 13 C NMR(75MHz, CDCl3)δ=184.20,177.28,156.77,154.51,136.54,135.76,134.58,131.17,128.40,128.12, 121.64,120.30,119.61,76.99,60.91,31.23,31.16,31.03,23.37,23.28,10.40.ESI-MS: m / z=843([M+H] + ).

[0036]

[0037] Catalyst I-1 was stirred with ethylamine solution (0.4 mL, 0.80 mmol, 2 M in THF) or 2-dimethylaminoethylamine (110 μL, 1.0 mmol) in methanol at room temperature until the color of the system changed from yellow to milky white. After the reaction was stopped, the mixture was filtered, and the filter cake was washed successively with diethyl ether and petroleum ether. The cake was then dried to obtain gray solid III-1 (167 mg, yield 64%) and white solid IV-1 (220 mg, yield 49%).

[0038] Catalyst III-1; 1 H NMR (300MHz, DMSO-d6) δ = 9.22 (s, 2H), 7.47 (s, 2H), 6.96–6.42 (m, 10H), 4.34 (d, J = 13.0Hz, 4H), 3.88–3.68 (m, 8 H),3.56(t,J=6.8Hz,4H),3.15(d,J=13.0Hz,4H),1.97–1.81(m,8H),1.18(t,J=7.1Hz,6H),1.05–0.91(m,12H). 13 C NMR (75MHz, DMSO) δ = 183.50, 180.12, 168.53, 163.73, 155.72, 152.25, 135.65, 133.80, 133.00, 127.98, 122.07, 118. 24,118.21,118.17,118.12,118.08,76.49,76.44,30.41,22.86,22.75,16.49,10.35,10.16.ESI-MS: m / z=869([M+H] + ).

[0039] Catalyst IV-1; 1 H NMR (300MHz, DMSO-d6) δ=9.55(s,2H),7.62(s,2H),6.95(s,4H),6.66–6.33(m,6H),4.34(d,J=12.9Hz,4H),3.83(t,J=7.7H z,4H),3.77–3.59(m,8H),3.14(d,J=12.9Hz,4H),2.46–2.37(m,4H),2.19(s,12H),2.00–1.76(m,8H),1.09–0.84(m,12H). 13 C NMR (75MHz, DMSO)δ=

[0040] 166.63,163.67,155.54,152.36,135.90,134.87,133.52,127.89,122.05,118.31,76.58 ,76.39,59.07,45.08,41.33,30.41,22.91,22.72,10.44,10.10.ESI-MS: m / z=955([M+H] + ).

[0041] Example 2

[0042] In this embodiment, styrene oxide was used as a substrate to confirm the activity of hydrogen-bonded donor calix[4] aromatic derivatives I-1, II-1, III-1, or IV-1 catalysts in the cycloaddition reaction of CO2 and epoxides. The experimental method was as follows: styrene oxide (2.0 mmol, 240 mg), catalyst (5 mol% of styrene oxide), and tetrabutylammonium iodide (10 mol% of styrene oxide) were weighed and added to test tubes containing 5 mL of water, and CO2 was introduced at atmospheric pressure and room temperature for 24 hours. The reaction was stopped, extracted with dichloromethane, separated, and separated by column chromatography (ethyl acetate: petroleum ether) to obtain cyclic carbonates.

[0043]

[0044] Table 1. Reaction effects of styrene oxide with CO2 under different catalysts

[0045]

[0046] The results are shown in Table 1. It can be seen that when calix[4]semi-squamous amide I-1 is used as a catalyst, its catalytic performance is significantly better than that of ortho-disubstituted calix[4]semi-squamous amide II-1. This may be because the NH groups of catalyst II-1 are closer together, and hydrogen bonds are formed in the molecule, which is not conducive to the catalytic reaction. On the other hand, calix[4]squamous amide catalysts III-1 and IV-1 may be because they have more NH groups, forming intramolecular hydrogen bonds or polymers, thus producing steric hindrance effects.

[0047] Therefore, we selected catalyst I-1 as the optimal catalyst.

[0048] Example 3

[0049] In this embodiment, styrene oxide was used as the substrate to systematically study the main influencing factors of the cycloaddition reaction of CO2 and epoxide catalyzed by calix[4]semisquamamide I-1, such as the type of co-catalyst, the amount of catalyst, the reaction solvent, the reaction temperature and the reaction time.

[0050] Table 2 shows the effect of different co-catalysts on the cycloaddition reaction of CO2 with epoxides catalyzed by cup [4] semi-squamamide I-1 catalyst.

[0051]

[0052] Table 3 shows the effect of catalyst dosage on the cycloaddition reaction of CO2 with epoxides catalyzed by cup [4] semi-semi-squamamide I-1 catalyst.

[0053]

[0054] Table 4 shows the effect of the reaction solvent on the cycloaddition reaction of CO2 with epoxides catalyzed by cup [4] semi-squamous amide I-1 catalyst.

[0055]

[0056]

[0057] Table 5 shows the effect of reaction temperature on the cycloaddition reaction of CO2 with epoxides catalyzed by cup [4] semisemi-squamamide I-1 catalyst.

[0058]

[0059] Table 6 shows the effect of reaction time on the cycloaddition reaction of CO2 with epoxide catalyzed by cup [4] semisemi-squamous amide I-1 at a reaction temperature of 40℃.

[0060]

[0061] The results of the optimized reaction conditions are shown in Tables 2, 3, 4, 5 and 6. Therefore, the optimal experimental conditions for the cycloaddition reaction of CO2 with epoxide catalyzed by cup[4] semisquamyl I-1 are: catalyst dosage of 5 mol%, co-catalyst (tetrabutylammonium iodide) of 10 mol%, water as solvent, reaction temperature of 40℃, and reaction time of 16 hours.

[0062] Example 4

[0063] This embodiment investigates the applicability of epoxides in the cycloaddition reaction of CO2 with epoxides catalyzed by cup[4] semisquamyl I-1 under the optimal experimental conditions in Example 3.

[0064] The experimental method was as follows: 2.0 mmol of epoxide, 5 mol% of calix[4] hemisquamamide I-1, and 10 mol% of tetrabutylammonium iodide were weighed and added to test tubes containing 5 mL of water. The mixture was magnetically stirred and reacted at 40 °C under normal pressure for 16 to 48 hours. After the reaction was completed, the mixture was extracted with dichloromethane, separated, and purified by silica gel column chromatography (ethyl acetate and petroleum ether). The experimental results are shown in Table 7.

[0065]

[0066] Table 7. Scope of Application of Epoxides

[0067]

[0068]

[0069] Based on the analysis of the reaction results and the construction of the catalyst, a possible reaction mechanism was hypothesized.

[0070] First, styrene oxide forms a hydrogen bond with the NH group of calix[4]semi-squamous amide I-1, polarizing the CO bond. At the same time, the benzene ring of styrene oxide is fixed due to the π··π effect of calixarene. Then, the iodide ion nucleophilically attacks to form transition state A. Then, styrene oxide ring-opens to form an anionic intermediate B, and the semi-squamous amide group reacts with O - Hydrogen bonds between ions can stabilize the intermediate; subsequently, CO2 is polarized by the intermediate O under the influence of hydrogen bonds. - The ion undergoes nucleophilic attack to form the carbonate anion C; finally, an intramolecular nucleophilic substitution cyclization reaction occurs to give a cyclic carbonate.

[0071] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A hydrogen-bonded calix[4] aromatic derivative, characterized in that: The hydrogen bond donor cup [4] aromatic derivative is one of the following structural formulas: ； ； ； 。 2. The application of the hydrogen bond donor calix [4] aromatic derivative as described in claim 1, characterized in that: Using a hydrogen bond donor cup [4] aromatic derivative as a catalyst and a quaternary ammonium salt as a co-catalyst, and with water as a solvent, the cycloaddition reaction of CO2 with epoxide was catalyzed to synthesize cyclic carbonates. The epoxide is one of styrene oxide, glycidyl phenyl ether, or substituted styrene oxide; the substituted styrene oxide is one in which the hydrogen on the benzene ring of styrene oxide is replaced by a substituent, and the substituent is one or more of fluorine, chlorine, bromine, nitro, trifluoromethyl, or methyl.

3. The application of the hydrogen bond donor calix [4] aromatic derivative as described in claim 2, characterized in that: The steps for the cycloaddition reaction of CO2 with epoxides are as follows: (1) Under normal pressure, using epoxide as raw material, hydrogen bond donor cup [4] aromatic derivative as catalyst, and quaternary ammonium salt as co-catalyst, cycloaddition reaction with CO2 is carried out in the presence of solvent. The reaction temperature is 25~100℃ and the reaction time is 6~48 hours. (2) After the reaction in step (1) is completed, the product is extracted with dichloromethane, separated by chromatography column, and purified to obtain cyclic carbonate product.

4. The application of the hydrogen bond donor calix [4] aromatic derivative as described in claim 3, characterized in that: The amount of the hydrogen bond donor cup [4] aromatic derivative is 3 to 10% of the molar amount of the epoxide; the amount of the quaternary ammonium salt is 5 to 15% of the molar amount of the epoxide.

5. The application of the hydrogen bond donor calix [4] aromatic derivative as described in claim 3, characterized in that: The quaternary ammonium salt is tetrabutylammonium iodide or tetrabutylammonium bromide.

6. The application of the hydrogen bond donor calix [4] aromatic derivative as described in claim 3, characterized in that: The catalyst is The catalyst is used at 5% of the molar amount of the epoxide; the quaternary ammonium salt is tetrabutylammonium iodide; the co-catalyst is used at 10% of the molar amount of the epoxide; and the reaction temperature is 40°C.

Images