Homogeneous catalytic composition, and one-pot method for preparing 5-hydroxymethylfurfural

Abstract

A homogeneous catalytic composition, and a one-pot method for preparing 5-hydroxymethylfurfural. The homogeneous catalytic composition comprises a homogeneous catalyst, a quaternary ammonium salt, and water. The homogeneous catalyst comprises a homogeneous Brønsted acid and a homogeneous Lewis acid. The quaternary ammonium salt is capable of forming an ion pair binding system with the homogeneous catalyst. The method comprises: reacting a homogeneous catalytic reaction system containing hexose and the homogeneous catalytic composition, then quenching the reaction, and performing separation on an obtained reaction mixture to obtain 5-hydroxymethylfurfural and the homogeneous catalytic composition. The 5-hydroxymethylfurfural in the method has a high yield and is convenient to separate, and the homogeneous catalytic composition used is convenient to recycle, is environment-friendly and economical, and has wide application prospects.

Description

Homogeneous catalytic composition and one-pot method for preparing 5-hydroxymethylfurfural

[0001] The present application claims priority to the Chinese patent application for invention with the application number CN202411126703.9, the application date of August 15, 2024, and the name of "Homogeneous catalytic composition and one-pot method for preparing 5-hydroxymethylfurfural", which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] The present application relates to a method for preparing a bio-based chemical, in particular to a homogeneous catalytic composition and its application in a one-pot method for synthesizing 5-hydroxymethylfurfural, belonging to the field of chemical technology. BACKGROUND

[0003] 5-hydroxymethylfurfural (HMF) is an important bio-based platform compound, and various important furan derivatives can be obtained through oxidation, hydrogenation, etherification, esterification, etc. Due to the F 5-ɑ configuration of fructose has an oxygen-containing five-membered ring, which is very easy to dehydrate to form the furan ring in HMF, so the synthesis of HMF from fructose has the advantages of mild reaction conditions, simple homogeneous catalytic composition, and high yield, and is the process widely used at present.

[0004] However, since fructose is mainly derived from the isomerization process of glucose, its price is much higher than that of glucose, sucrose and other raw materials, resulting in high production cost of HMF prepared from fructose. If glucose and other widely available six-carbon sugars are efficiently converted into HMF, the raw material cost can be greatly reduced. In this process, the six-carbon sugar needs to be first isomerized into ketohexose (fructose), and then the fructose is converted into HMF through a dehydration reaction. In the first step of isomerization reaction, a Lewis acid catalyst is needed for catalytic reaction, while in the second step of dehydration reaction, an acid catalyst is needed for reaction. Due to the mutual influence of the two types of catalysts, the existing one-pot method for preparing HMF cannot obtain high HMF yield, and at the same time, due to the easy polymerization of the product HMF at high concentration, the concentration of six-carbon sugar in the existing technology is relatively low.

[0005] How to construct an efficient catalytic system to efficiently relay the conversion of carbohydrates into HMF and further improve the yield of 5-hydroxymethylfurfural is a key problem in the field.

[0006] SUMMARY

[0007] The main purpose of the present application is to provide a homogeneous catalytic composition and a one-pot method for synthesizing 5-hydroxymethylfurfural to overcome the shortcomings of the prior art.

[0008] ​To achieve the above object, the technical scheme of the present application comprises the following.

[0009] The first aspect of the present application provides a homogeneous catalytic composition comprising a homogeneous catalyst, a quaternary ammonium salt and water; the homogeneous catalyst comprises a homogeneous acid and a homogeneous Lewis acid; and the quaternary ammonium salt is capable of forming an ion pair binding system with the homogeneous acid and the homogeneous Lewis acid catalyst.

[0010] The second aspect of the present application provides the use of the homogeneous catalytic composition in a method for preparing 5-hydroxymethylfurfural from a six-carbon sugar.

[0011] The third aspect of the present application provides a one-pot method for preparing 5-hydroxymethylfurfural, which comprises: reacting a homogeneous catalytic reaction system comprising a six-carbon sugar and the homogeneous catalytic composition, then quenching the reaction, and then separating 5-hydroxymethylfurfural and the homogeneous catalytic composition from the obtained reaction mixture.

[0012] Compared with the prior art, the present application has at least the following advantages:

[0013] (1) The present application uses an ion pair binding homogeneous catalytic composition comprising a quaternary ammonium salt and a homogeneous catalyst to carry out the dehydration reaction of a six-carbon sugar including glucose. From the reaction mechanism, on the one hand, the homogeneous catalyst comprises a homogeneous acid and a homogeneous Lewis acid, and the isomerization reaction and the dehydration reaction are coupled, realizing the one-pot preparation of 5-hydroxymethylfurfural. On the other hand, the quaternary ammonium salt and the six-carbon sugar can form rich intermolecular hydrogen bonds in the presence of water as a cosolvent, thereby reducing the melting point of the two, forming a eutectic system. At the same time, the two are miscible in a wide range of mass ratios, which can increase the concentration of the six-carbon sugar in the reaction, increase the processing capacity of the raw materials, and ultimately improve the generation rate of 5-hydroxymethylfurfural.

[0014] (2) In traditional aqueous solvents and organic solvents, the protons generated by the acid are distributed in the solvent in a free state, freely interacting with the raw material molecules, product molecules and solvent molecules, resulting in the degradation of 5-hydroxymethylfurfural generated by the dehydration of the six-carbon sugar to form byproducts. In the ion pair binding homogeneous catalytic system of the present application, the quaternary ammonium salt has a high polarity and is more likely to bind protons, thereby reducing the proportion of free protons in the solution, avoiding the catalytic reaction of 5-hydroxymethylfurfural to form byproducts, and improving the overall yield of 5-hydroxymethylfurfural.

[0015] (3) In the homogeneous catalytic reaction system of the present application, the Lewis acid, The polarities of the acid, the six-carbon sugar and the quaternary ammonium salt are much greater than that of the product 5-hydroxymethylfurfural, so in the reaction process, the Lewis acid, The interaction among the acid, the six-carbon sugar and the quaternary ammonium salt is much greater than that between them and 5-hydroxymethylfurfural, so the 5-hydroxymethylfurfural molecules will constantly gather to form microdroplets, thereby achieving the effect of being stabilized.

[0016] (4) The one-pot synthesis process provided by the present application can simply, safely and efficiently synthesize 5-hydroxymethylfurfural under mild conditions, and the six-carbon sugar treatment amount is large and the yield of the target product is high in the whole process. Meanwhile, due to the great difference in polarity between the quaternary ammonium salt and 5-hydroxymethylfurfural, the quaternary ammonium salt and the 5-hydroxymethylfurfural produced in the reaction can be simply separated by using an organic solvent. And due to the binding of the ion pair formed by the ionic association between the quaternary ammonium salt and the homogeneous acid, the loss amount of the two is extremely low. The quaternary ammonium salt and the homogeneous acid can be used for recycling after distillation and dehydration, which greatly reduces the raw material, solvent and catalyst costs in the production of 5-hydroxymethylfurfural.

[0017] (5) The yield and purity of the target product 5-hydroxymethylfurfural in the one-pot synthesis process provided by the present application are both high, and the preparation process is simple, the energy consumption is low, the manufacturing cost is low, and it is extremely suitable for large-scale industrial promotion.

[0018] (6) In the one-pot synthesis process provided by the present application, the amount of water separated in the process of the reduced pressure dehydration reaction can be used to judge the degree of reaction, so as to avoid overreaction, thereby preventing the target product 5-hydroxymethylfurfural from being dehydrated to form humin.

[0019] (7) The one-pot synthesis process provided by the present application only needs to use a small amount of homogeneous catalyst to obtain a high yield of 5-hydroxymethylfurfural (the yield can be as high as 95% and the purity is more than 99%), and the homogeneous catalytic composition does not contain metal, which reduces the impact on the environment, is green and environmentally friendly, and meets the requirements of sustainable development. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present application, the drawings involved in the embodiments are briefly introduced as follows.

[0021] FIG. 1 is an H NMR chart of 5-hydroxymethylfurfural prepared in Example 15. 1

[0022] FIG. 2 is a C NMR chart of 5-hydroxymethylfurfural prepared in Example 15. 13

[0023] FIG. 3 is an HPLC chart of 5-hydroxymethylfurfural prepared in Example 15. DETAILED DESCRIPTION

[0024] ​​As described above, the prior art one-pot synthesis of HMF from glucose and other six-carbon sugars has the following disadvantages, i.e., the Lewis acid catalyst and the acid catalyst interact with each other, so that a higher HMF yield cannot be obtained, and HMF is also prone to polymerization in the reaction system, so that a higher concentration of six-carbon sugars cannot be used in the reaction system.

[0025] In view of the above-mentioned deficiencies in the prior art, the inventors of the present application have obtained the technical solution of the present application through long-term research and practice, which will be explained in detail as follows.

[0026] Some embodiments of the present application provide a homogeneous catalytic composition comprising a homogeneous catalyst, a quaternary ammonium salt and water; the homogeneous catalyst comprises a homogeneous acid and a homogeneous Lewis acid; the quaternary ammonium salt is capable of forming an ion pair binding system with the homogeneous acid and the homogeneous Lewis acid.

[0027] In one embodiment, the mass ratio of the quaternary ammonium salt, water and the homogeneous catalyst is 20-80:4-20:0.1-5, wherein the mass ratio of the homogeneous acid and the homogeneous Lewis acid is 1:1-1:20, preferably 1:5-1:20, so as to obtain better catalytic activity and a higher yield of 5-hydroxymethylfurfural.

[0028] In one embodiment, the homogeneous catalyst consists of a homogeneous acid and a homogeneous Lewis acid.

[0029] In one embodiment, the quaternary ammonium salt comprises a substance with the general formula R4NX, wherein the hydrocarbon group R comprises substituted and / or unsubstituted alkyl and / or aryl groups, and the substituted and / or unsubstituted alkyl groups are preferably substituted or unsubstituted C1-C 18 alkyl groups, and X comprises F - , Cl - , Br - , I - , NO2 - , NO3 - or SO4 2- . For example, the quaternary ammonium salt can be selected from, but not limited to, tetraethylammonium bromide, tetraethylammonium chloride, tetramethylammonium iodide, tetrabutylammonium fluoride, tetrapropylammonium chloride, trimethylhexadecylammonium bromide, trimethyloctadecylammonium chloride, tetraethylammonium nitrate, tetraethylammonium nitrite, choline bromide and the like.

[0030] In one embodiment, the homogeneous ​​​​​The acid includes one or more of HF, HC1, HBr, HI, H2SO4, HNO3, trifluoromethanesulfonic acid, benzene sulfonic acid, methanesulfonic acid, p-toluenesulfonic acid, dodecylbenzenesulfonic acid, or the like, and is not limited thereto.

[0031] In one embodiment, the homogeneous Lewis acid includes a metal salt. More preferably, the cation in the metal salt includes one or more of Mg 2+ , Ca 2+ , Al 3+ , Sn 2+ , Sn 4+ , Fe 2+ , Fe 3+ , Ni 2+ , Co 2+ , Cu 2+ , Cu + , Cr 3+ , Cr 2+ , Zr 4+ , and the anion includes one or more of F - , Cl - , Br - , I - , SO4 2- , SO3 2- , HSO3 - , NO3 - , CO3 2- , HCO3 - , PO4 3- , HPO3 2- , H2PO3 - , C2O4 2- , CH3COO - , or the like, and is not limited thereto.

[0032] Some embodiments of the present application also provide the use of the homogeneous catalytic composition in the synthesis of 5-hydroxymethylfurfural from hexose.

[0033] In the above embodiments of the present application, by employing the ionic pair formed between the quaternary ammonium salt and the homogeneous acid and the homogeneous Lewis acid, and then forming the homogeneous catalytic reaction system with hexose, the reactivity of glucose and other hexoses can be significantly improved, and thus the production efficiency and yield of 5-hydroxymethylfurfural can be effectively improved.

[0034] Some embodiments of the present application provide a method for preparing 5-hydroxymethylfurfural in one pot, which comprises: allowing a homogeneous catalytic reaction system comprising a six-carbon sugar and the homogeneous catalytic composition to react, then quenching the reaction with a quenching agent, and then separating 5-hydroxymethylfurfural and the homogeneous catalytic composition from the obtained reaction mixture.

[0035] In one embodiment, the homogeneous catalytic reaction system comprises a six-carbon sugar, a quaternary ammonium salt, water and a homogeneous catalyst in a mass ratio of 15-50:20-80:4N20:0.1N5.

[0036] More preferably, the homogeneous catalytic reaction system comprises 20wt%-50wt% of the six-carbon sugar and 0.1wt%-5wt% of the homogeneous catalyst.

[0037] In one embodiment, the six-carbon sugar comprises any combination of one or more of glucose, fructose, galactose, mannose, sorbose, sucrose, inulin, hydrolyzed starch, cellulose and algal polysaccharide, and is not limited thereto. More preferably, the six-carbon sugar comprises glucose.

[0038] In one embodiment, the reaction is carried out at a temperature of 50-200°C, preferably 60-120°C. Too high or too low temperature will reduce the yield of 5-hydroxymethylfurfural.

[0039] In one embodiment, the reaction is carried out under reduced pressure. Further, the pressure of the reaction is preferably -0.1Mpa to -0.015MPa, more preferably -0.1MPa to -0.075MPa, and more preferably -0.1MPa to -0.08MPa, so as to make the reaction more fully.

[0040] In one embodiment, the reaction is carried out for 5min-240min.

[0041] In one embodiment, the pH value of the reaction system is maintained at 0-1 during the reaction.

[0042] In one embodiment, the method specifically comprises:

[0043] at least uniformly mixing a quaternary ammonium salt, a homogeneous acid, a homogeneous Lewis acid and water to obtain a homogeneous catalytic composition;

[0044] Then, the homogeneous catalytic composition is uniformly mixed with a six-carbon sugar to obtain the homogeneous catalytic reaction system.

[0045] More preferably, the homogeneous catalytic composition and / or the homogeneous catalytic reaction system is prepared at a temperature of 20-100°C.

[0046] For example, the construction of the homogeneous catalytic reaction system specifically includes:

[0047] (a) stirring the quaternary ammonium salt, the homogeneous acid, the homogeneous Lewis acid and water uniformly, and promoting the combination of the quaternary ammonium salt and the homogeneous acid by the ionic association interaction between them;

[0048] (b) adding the six-carbon sugar into the mixture obtained in step (a) and stirring uniformly to form the homogeneous catalytic reaction system.

[0049] Further, in the above embodiment, the quaternary ammonium salt, the homogeneous acid, the homogeneous Lewis acid and water can be mixed in any way, and after being mixed uniformly, a paste-like mixture with poor fluidity is formed. Then the six-carbon sugar is added into the paste-like mixture and mixed uniformly, especially at 20-100°C, to form a homogeneous transparent single-phase liquid, i.e. the homogeneous catalytic reaction system. In the above mixing process, the ionic association interaction between the quaternary ammonium salt and the homogeneous acid, the homogeneous Lewis acid promotes the combination of the two, and the ionic pair binding effect is generated. The six-carbon sugar (if sugar) and the quaternary ammonium salt promote the melting of the two at a temperature lower than the melting point by forming intermolecular hydrogen bonds. The small amount of water added serves as a medium to promote the formation of intermolecular hydrogen bonds between the fructose and the quaternary ammonium salt, so that the mixture composition forms a eutectic system, and finally a homogeneous transparent single-phase system is formed.

[0050] In one embodiment, the method specifically includes: after the reaction is completed, a quenching agent is added into the reaction system to quench the reaction, so as to obtain the reaction mixture.

[0051] Further, the quenching agent includes water.

[0052] Further, the amount of the quenching agent added is 1-5 times of the total mass of the reaction system.

[0053] Further, the quenching agent is added after the reaction is completed and the reaction system returns to normal pressure.

[0054] In one embodiment, the method specifically includes:

[0055] extracting the reaction mixture with an extractant to obtain a light phase and a heavy phase;

[0056] separating and obtaining the 5-hydroxymethylfurfural from at least the light phase;

[0057] and, separating and recovering the homogeneous catalyst from at least the heavy phase.

[0058] Further, the extractant includes an organic solvent, which includes any combination of one or more of petroleum ether, cyclohexane, n-hexane, diethyl ether, ethyl acetate, acetonitrile, dichloroethane, tetrahydrofuran, and the like, and is not limited thereto.

[0059] Further, the extractant is added in an amount of 1 to 5 times the mass of the reaction mixture.

[0060] Further, the extraction method includes, but is not limited to, one of single-stage extraction, multi-stage countercurrent extraction, or multi-stage crossflow extraction.

[0061] In view of the existing process for synthesizing HMF from hexose, the dehydration reaction process has many side reactions, the byproduct structure is complex, the byproducts and 5-hydroxymethylfurfural can polymerize to form humin, which is difficult to handle, and adheres to the reactor, affecting the subsequent reaction process. At the same time, due to the low melting point and high boiling point of 5-hydroxymethylfurfural, and good compatibility, it is difficult to obtain a high yield of 5-hydroxymethylfurfural by using separation means such as crystallization, distillation, and extraction, and therefore it is difficult to separate and purify 5-hydroxymethylfurfural in the prior art.

[0062] In the above embodiments of the present application, by using the above ion binding pair, HMF can be simply, safely and efficiently synthesized under mild conditions, the entire process has a large amount of hexose, and the yield of the target product HMF is high. By using a quenching and extraction method matched with the homogeneous catalytic reaction system, the highly sensitive HMF can be quickly stabilized and separated to obtain a pure product at the reaction endpoint. In particular, due to the large polarity difference between the quaternary ammonium salt and HMF, simple extraction using an organic solvent can separate the quaternary ammonium salt from the HMF produced in the reaction, and thus the yield of HMF can be as high as 95%, and the purity can be above 99%.

[0063] Further, the method can include: separating and recovering the extractant and part of the water in the heavy phase by at least a reduced pressure distillation method, and obtaining 5-hydroxymethylfurfural.

[0064] Further, the method can include: separating the extractant and part of the water in the heavy phase, and thus recovering the homogeneous catalytic composition.

[0065] Illustratively, the method specifically includes: separating the extractant and part of the water in the heavy phase by at least a reduced pressure distillation method.

[0066] More preferably, the method further includes: uniformly mixing the recovered homogeneous catalytic composition with hexose, so as to form the homogeneous catalytic reaction system again.

[0067] In one embodiment, the method specifically includes:

[0068] a quaternary ammonium salt, a homogeneous a homogeneous catalytic composition is obtained, and then the homogeneous catalytic composition is mixed with a six-carbon sugar to form the homogeneous catalytic reaction system;

[0069] The homogeneous catalytic reaction system is subjected to the reaction under reduced pressure in a sealed reaction solvent;

[0070] After the reaction is completed, the reaction system is returned to normal pressure, a quenching agent is added to quench the reaction, and then an extractant is used to extract the reaction mixture to obtain a light phase and a heavy phase;

[0071] The extractant is separated and recovered from the light phase, and 5-hydroxymethylfurfural is obtained;

[0072] The extractant and part of the water in the heavy phase are separated to recover the homogeneous catalytic composition;

[0073] The recovered homogeneous catalytic composition is mixed with a six-carbon sugar to form the homogeneous catalytic reaction system again.

[0074] For example, the method can include the following steps:

[0075] (1) The homogeneous catalytic reaction system is transferred to a sealed reaction container for heating, and the reaction is carried out under reduced pressure;

[0076] (2) After step (1) is completed, the homogeneous catalytic reaction system is returned to normal pressure, a quenching agent is added to quench the reaction, and then an extractant is used to extract the reaction product to obtain a light phase and a heavy phase;

[0077] (3) The light phase is subjected to reduced pressure distillation to recover the extractant, and 5-hydroxymethylfurfural with a purity of >97% is obtained;

[0078] (4) The heavy phase is subjected to reduced pressure distillation to separate the residual extractant and excess water, which can be used as a reusable homogeneous catalytic composition.

[0079] In the above embodiment, the heavy phase separated after extraction is an aqueous phase containing a quaternary ammonium salt, a homogeneous acid, a quenching agent, and residual extractant. The heavy phase is collected at different temperatures to first recover the residual organic extractant in the heavy phase, and then the water in the heavy phase is separated to remove excess water (including the water added in the quenching stage and the water generated in the dehydration reaction) by controlling the amount of water separated, so that a mixed system consistent with the above homogeneous catalytic composition can be obtained. The mixed system can be repeatedly used in the dehydration reaction of a six-carbon sugar, and can be used for more than 30 times while maintaining a catalytic efficiency of more than 90%.

[0080] In the above embodiments of the present application, the conversion rate of the six-carbon sugar is >98%, the yield of 5-hydroxymethylfurfural is >75%, and the purity of the separated 5-hydroxymethylfurfural is >97%.

[0081] The one-pot method for preparing 5-hydroxymethylfurfural provided in the above embodiments of the present application includes two processes of constructing a homogeneous catalytic composition and using the homogeneous catalytic composition for a six-carbon sugar dehydration reaction to prepare 5-hydroxymethylfurfural, in which a water-assisted quaternary ammonium salt and a six-carbon sugar form a eutectic system, a “quaternary ammonium salt bound homogeneous acid” ion pair forms a stable homogeneous catalyst, and the quaternary ammonium salt solvent, the Lewis acid catalyst, and the acid catalyst interact with each other and form a suitable reaction system, the six-carbon sugar is efficiently relayed through a fructose intermediate to 5-hydroxymethylfurfural, and then through quenching of the reaction, extraction of the reaction product, and separation by vacuum distillation, 5-hydroxymethylfurfural with a purity of >97% can be obtained, which has high yield, convenient separation, and good recycling performance. The ion pair binding system formed between the quaternary ammonium salt, the homogeneous acid, and the homogeneous Lewis acid catalyst is easy to separate from the product and is convenient for repeated recycling, has good recycling performance, and can be repeatedly used for more than 30 times under industrial conditions, is green and environmentally friendly, greatly reduces the cost of raw materials, solvents, and catalysts in the production process of 5-hydroxymethylfurfural, has good economic efficiency, and has a broad application prospect.

[0082] The present application will be described in detail below in conjunction with the embodiments, but the embodiments of the present application are not limited thereto. Obviously, the embodiments described below are only some of the embodiments of the present application, and other similar embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0083] Unless otherwise specified, the raw materials used in the following embodiments can be obtained from the market or self-made according to the references, and the production equipment, test equipment, and test methods used can also be common equipment or methods in the art.

[0084] In the following embodiments, the calculation formula of the production rate is as follows: Yield = (actual yield / theoretical yield) x 100%.

[0085] Embodiment 1: The construction method of a homogeneous catalytic reaction system provided in the present embodiment includes the following steps:

[0086] Step a: tetraethylammonium bromide, methanesulfonic acid, CrCl3, and water are added to a reactor and mixed uniformly, and heated to 50°C and stirred at constant temperature.

[0087] Step b, glucose is added into the mixture obtained in step a, and the stirring is continued to form a homogeneous single-phase mixture. The mass ratio of quaternary ammonium salt, glucose, methanesulfonic acid, CrCl3 and water in the homogeneous single-phase mixture is 60:30:0.5:0.5:9.

[0088] Example 2: The construction method of the homogeneous phase catalytic reaction system provided in this example includes the following steps:

[0089] Step a, tetraethylammonium chloride, trifluoromethyl sulfonic acid, CrCl3 and water are added into a reactor and mixed uniformly, and heated to 100°C and stirred at constant temperature.

[0090] Step b, glucose is added into the mixture obtained in step a, and the stirring is continued to form a homogeneous single-phase mixture. The mass ratio of quaternary ammonium salt, glucose, trifluoromethyl sulfonic acid, CrCl3 and water in the homogeneous single-phase mixture is 15:80:0.5:2.5:5.

[0091] Example 3: The construction method of the homogeneous phase catalytic reaction system provided in this example includes the following steps:

[0092] Step a, tetramethylammonium iodide, benzenesulfonic acid, CrCl3 and water are added into a reactor and mixed uniformly, and heated to 50°C and stirred at constant temperature.

[0093] Step b, glucose is added into the mixture obtained in step a, and the stirring is continued to form a homogeneous single-phase mixture. The mass ratio of quaternary ammonium salt, glucose, benzenesulfonic acid, CrCl3 and water in the homogeneous single-phase mixture is 27:20:1:1:20.

[0094] Example 4: The construction method of the homogeneous phase catalytic reaction system provided in this example includes the following steps:

[0095] Step a, tetraethylammonium bromide, hydrofluoric acid, AlCl3 and water are added into a reactor and mixed uniformly, and heated to 50°C and stirred at constant temperature.

[0096] Step b, glucose syrup is added into the mixture obtained in step a, and the stirring is continued to form a homogeneous single-phase mixture. The mass ratio of quaternary ammonium salt, glucose syrup, hydrofluoric acid, AlCl3 and water in the homogeneous single-phase mixture is 50:42:1:2:5.

[0097] Example 5: The construction method of the homogeneous phase catalytic reaction system provided in this example includes the following steps:

[0098] Step a, tetraethylammonium bromide, hydrofluoric acid, AlCl3 and water are added into a reactor and mixed uniformly, and heated to 50°C and stirred at constant temperature.

[0099] Step b, add high glucose syrup into the mixture obtained in step a, continue to stir to form a homogeneous single-phase mixture. The mass ratio of quaternary ammonium salt, high glucose syrup, sulfuric acid, SnCl4 and water in the homogeneous single-phase mixture is 64:24:2:2:8.

[0100] Example 6: The construction method of a homogeneous phase catalytic reaction system provided in this example includes the following steps:

[0101] Step a, add tetrapropylammonium chloride, nitric acid, SnCl4 and water into the reactor and mix uniformly, heat to 80°C and constant temperature stirring.

[0102] Step b, add glucose syrup into the mixture obtained in step a, continue to stir to form a homogeneous single-phase mixture. The mass ratio of quaternary ammonium salt, glucose syrup, nitric acid, SnCl4 and water in the homogeneous single-phase mixture is 40:50:0.2:3.8:6.

[0103] Example 7: The construction method of a homogeneous phase catalytic reaction system provided in this example includes the following steps:

[0104] Step a, add trimethylhexadecylammonium bromide, methanesulfonic acid, CrCl3 and water into the reactor and mix uniformly, constant temperature stirring at 20°C.

[0105] Step b, add crystalline glucose into the mixture obtained in step a, continue to stir to form a homogeneous single-phase mixture. The mass ratio of quaternary ammonium salt, crystalline glucose, methanesulfonic acid, CrCl3 and water in the homogeneous single-phase mixture is 60:25:0.5:4.5:10.

[0106] Example 8: The construction method of a homogeneous phase catalytic reaction system provided in this example includes the following steps:

[0107] Step a, add trimethyloctadecylammonium chloride, p-toluene sulfonic acid, FeCl3 and water into the reactor and mix uniformly, heat to 80°C and constant temperature stirring.

[0108] Step b, add sucrose into the mixture obtained in step a, continue to stir to form a homogeneous single-phase mixture. The mass ratio of quaternary ammonium salt, sucrose, p-toluene sulfonic acid, FeCl3 and water in the homogeneous single-phase mixture is 40:30:2:3:20.

[0109] Example 9: The construction method of a homogeneous phase catalytic reaction system provided in this example includes the following steps:

[0110] Step a, add tetraethylammonium nitrate, hydrochloric acid, CrCl3 and water into the reactor and mix uniformly, heat to 50°C and constant temperature stirring.

[0111] Step b, crystalline glucose is added into the mixture obtained in step a, and the stirring is continued to form a homogeneous single-phase mixture. The mass ratio of quaternary ammonium salt, crystalline glucose, hydrochloric acid, CrCl3 and water in the homogeneous single-phase mixture is 60:30:0.5:1.5:8.

[0112] Example 10: The construction method of a homogeneous catalytic reaction system provided in this example includes the following steps:

[0113] Step a, tetraethylammonium nitrite, HI, CrCl3 and water are added into the reactor and mixed uniformly, heated to 30°C, and constant temperature stirring.

[0114] Step b, crystalline glucose is added into the mixture obtained in step a, and the stirring is continued to form a homogeneous single-phase mixture. The mass ratio of quaternary ammonium salt, crystalline glucose, HI, CrCl3 and water in the homogeneous single-phase mixture is 70:18:0.5:1.5:10.

[0115] Example 11: The construction method of a homogeneous catalytic reaction system provided in this example includes the following steps:

[0116] Step a, tetraethylammonium fluoride, p-toluenesulfonic acid, Al2(SO4)3 and water are added into the reactor and mixed uniformly, heated to 40°C, and constant temperature stirring.

[0117] Step b, mannose is added into the mixture obtained in step a, and the stirring is continued to form a homogeneous single-phase mixture. The mass ratio of quaternary ammonium salt, mannose, dodecylbenzenesulfonic acid, Al2(SO4)3 and water in the homogeneous single-phase mixture is 40:40:0.5:4.5:15.

[0118] Example 12: The construction method of a homogeneous catalytic reaction system provided in this example includes the following steps:

[0119] Step a, choline bromide, dodecylbenzenesulfonic acid, Al2(SO4)3 and water are added into the reactor and mixed uniformly, heated to 40°C, and constant temperature stirring.

[0120] Step b, crystalline fructose is added into the mixture obtained in step a, and the stirring is continued to form a homogeneous single-phase mixture. The mass ratio of quaternary ammonium salt, crystalline fructose, dodecylbenzenesulfonic acid, Al2(SO4)3 and water in the homogeneous single-phase mixture is 40:40:0.5:4.5:15.

[0121] Example 13: The construction method of a homogeneous catalytic reaction system provided in this example includes the following steps:

[0122] Step a, choline chloride, nitric acid, Al(NO3)3 and water are added into the reactor and mixed uniformly, heated to 70°C, and constant temperature stirring.

[0123] Step b, crystalline fructose was added into the mixture obtained in step a, and the stirring was continued to form a homogeneous single-phase mixture. The mass ratio of quaternary ammonium salt, crystalline fructose, nitric acid, Al(NO3)3 and water in the homogeneous single-phase mixture was 30:50:2:3:15.

[0124] Example 14: The method for constructing a homogeneous catalytic reaction system provided in this example includes the following steps:

[0125] Step a, tetraethylammonium bromide, methanesulfonic acid, CrCl3 and water were added into a reactor and mixed uniformly, and heated to 50°C and stirred at constant temperature.

[0126] Step b, glucose was added into the mixture obtained in step a, and the stirring was continued to form a homogeneous single-phase mixture. The mass ratio of quaternary ammonium salt, glucose, methanesulfonic acid, CrCl3 and water in the homogeneous single-phase mixture was 60:30:0.1:0.9:9.

[0127] Example 15: The method for one-pot preparation of 5-hydroxymethylfurfural provided in this example includes the following steps:

[0128] The homogeneous catalytic reaction system obtained in Example 1 was transferred to a sealed reaction container, and the reaction pressure was set to -0.09 MPa, the reaction temperature was set to 80°C, and the reaction time was set to 60 min. After the reaction was completed, the pressure in the reaction container was restored to normal pressure conditions, and water was added as a quenching agent to quench the reaction. The reaction mixture was analyzed by liquid chromatography, and then ethyl acetate was used as an extractant to extract 5-hydroxymethylfurfural by cross-flow extraction. After the extraction was completed, the light phase and the heavy phase were separated. The light phase was separated and recovered by reduced pressure distillation to separate the extractant, and 5-hydroxymethylfurfural was obtained. The heavy phase was separated and recovered by reduced pressure distillation to separate the residual extractant and excess water, and a reusable ion pair bound homogeneous catalyst was obtained. The mass ratio of the quenching agent to the homogeneous catalytic reaction system in the above process was 2:1, and the mass ratio of the extractant to the total system after quenching (i.e. the above reaction mixture) was 4:1. The results showed that the glucose conversion rate in this example was 98%, the yield of 5-hydroxymethylfurfural was 81%, and the purity was 99%. Figures 1-3 show the H NMR chart, C NMR chart and HPLC chart of 5-hydroxymethylfurfural prepared in this example. The yield of 5-hydroxymethylfurfural could still reach 77% when the ion pair bound homogeneous catalyst was recycled for 30 times. 1 H NMR chart, 13 C NMR chart and HPLC chart. The yield of 5-hydroxymethylfurfural could still reach 77% when the ion pair bound homogeneous catalyst was recycled for 30 times.

[0129] Example 16: The method for one-pot preparation of 5-hydroxymethylfurfural provided in this example includes the following steps:

[0130] The homogeneous catalytic reaction system obtained in Example 2 was transferred to a closed reaction vessel, the reaction pressure was set to -0.08 MPa, the reaction temperature was set to 120°C, the reaction time was set to 240 min, after the reaction was completed, the pressure in the reaction vessel was restored to normal pressure conditions, water was added as a quenching agent to quench the reaction, the reaction mixture was analyzed by liquid chromatography, then n-hexane was used as an extractant, 5-hydroxymethylfurfural was extracted by cross-flow extraction, after the extraction was completed, the light phase and the heavy phase were separated; the light phase was separated and the extractant was recovered by vacuum distillation, and 5-hydroxymethylfurfural was obtained; the heavy phase was separated and the residual extractant and excess water were removed by vacuum distillation, and the ion pair bound homogeneous catalyst that could be reused was obtained. The mass ratio of the quenching agent to the homogeneous catalytic reaction system in the above process was 5:1, and the mass ratio of the extractant to the total system after quenching (i.e. the above reaction mixture) was 3:1. The results showed that the glucose conversion rate in this example was 98%, the yield of 5-hydroxymethylfurfural was 75%, and the purity was 99%. When the aforementioned ion pair bound homogeneous catalyst was recycled for 30 times, the yield of 5-hydroxymethylfurfural still maintained at 70%.

[0131] Example 17: A one-pot method for preparing 5-hydroxymethylfurfural provided in this example includes the following steps:

[0132] The ion pair bound homogeneous catalytic reaction system obtained in Example 3 was transferred to a closed reaction vessel, the reaction pressure was set to -0.03 MPa, the reaction temperature was set to 120°C, the reaction time was set to 60 min, after the reaction was completed, the pressure in the reaction vessel was restored to normal pressure conditions, water was added as a quenching agent to quench the reaction, the reaction mixture was analyzed by liquid chromatography, then cyclohexane was used as an extractant, 5-hydroxymethylfurfural was extracted by countercurrent extraction, after the extraction was completed, the light phase and the heavy phase were separated; the light phase was separated and the extractant was recovered by vacuum distillation, and 5-hydroxymethylfurfural was obtained; the heavy phase was separated and the residual extractant and excess water were removed by vacuum distillation, and the ion pair bound homogeneous catalyst that could be reused was obtained. The mass ratio of the quenching agent to the homogeneous catalytic reaction system in the above process was 1:1, and the mass ratio of the extractant to the total system after quenching (i.e. the above reaction mixture) was 2:1. The results showed that the glucose conversion rate in this example was 98%, the yield of 5-hydroxymethylfurfural was 80%, and the purity was 99%. When the aforementioned ion pair bound homogeneous catalyst was recycled for 30 times, the yield of 5-hydroxymethylfurfural still maintained at 75%.

[0133] Example 18: A one-pot method for preparing 5-hydroxymethylfurfural provided in this example includes the following steps:

[0134] The ion pair bound homogeneous catalytic reaction system obtained in Example 4 was transferred to a closed reaction vessel, the reaction pressure was set to -0.08 MPa, the reaction temperature was set to 150°C, the reaction time was set to 45 min, after the reaction was completed, the pressure in the reaction vessel was restored to normal pressure conditions, water was added as a quenching agent to quench the reaction, the reaction mixture was analyzed by liquid chromatography, then petroleum ether was used as an extractant, 5-hydroxymethylfurfural was extracted by countercurrent extraction, after the extraction was completed, the light phase and the heavy phase were separated; the light phase was separated and the extractant was recovered by vacuum distillation, 5-hydroxymethylfurfural was obtained; the heavy phase was separated and the residual extractant and excess water were removed by vacuum distillation, and a reusable ion pair bound homogeneous catalyst was obtained. The mass ratio of the quenching agent to the homogeneous catalytic reaction system in the above process was 3:1, and the mass ratio of the extractant to the total system after quenching (i.e. the above reaction mixture) was 5:1. The results showed that the glucose conversion rate in this example was 98%, the yield of 5-hydroxymethylfurfural was 80%, and the purity was 98%. When the aforementioned ion pair bound homogeneous catalyst was recycled for 30 times, the yield of 5-hydroxymethylfurfural still maintained at 80%.

[0135] Example 19: A one-pot method for preparing 5-hydroxymethylfurfural provided in this example includes the following steps:

[0136] The homogeneous catalytic reaction system obtained in Example 5 was transferred to a closed reaction vessel, the reaction pressure was set to -0.05 MPa, the reaction temperature was set to 200°C, the reaction time was set to 30 min, after the reaction was completed, the pressure in the reaction vessel was restored to normal pressure conditions, water was added as a quenching agent to quench the reaction, the reaction mixture was analyzed by liquid chromatography, then diethyl ether was used as an extractant, 5-hydroxymethylfurfural was extracted by countercurrent extraction, after the extraction was completed, the light phase and the heavy phase were separated; the light phase was separated and the extractant was recovered by vacuum distillation, 5-hydroxymethylfurfural was obtained; the heavy phase was separated and the residual extractant and excess water were removed by vacuum distillation, and a reusable ion pair bound homogeneous catalyst was obtained. The mass ratio of the quenching agent to the homogeneous catalytic reaction system in the above process was 1:1, and the mass ratio of the extractant to the total system after quenching (i.e. the above reaction mixture) was 1:1. The results showed that the glucose conversion rate in this example was 98%, the yield of 5-hydroxymethylfurfural was 80%, and the purity was 98%. When the aforementioned ion pair bound homogeneous catalyst was recycled for 30 times, the yield of 5-hydroxymethylfurfural still maintained at 80%.

[0137] Example 20: A one-pot method for preparing 5-hydroxymethylfurfural provided in this example includes the following steps:

[0138] The homogeneous catalytic reaction system obtained in Example 6 was transferred to a closed reaction vessel, the reaction pressure was set to -0.05 MPa, the reaction temperature was set to 180°C, the reaction time was set to 20 min, after the reaction was completed, the pressure in the reaction vessel was restored to normal pressure conditions, water was added as a quenching agent to quench the reaction, the reaction mixture was analyzed by liquid chromatography, then acetonitrile was used as an extractant to extract 5-hydroxymethylfurfural by countercurrent extraction, after the extraction was completed, the light phase and the heavy phase were separated; the light phase was separated by vacuum distillation to recover the extractant to obtain 5-hydroxymethylfurfural; the heavy phase was separated by vacuum distillation to separate the residual extractant and excess water to obtain a reusable ion pair bound homogeneous catalyst. The mass ratio of the quenching agent to the homogeneous catalytic reaction system in the above process was 5:1, and the mass ratio of the extractant to the total system after quenching (i.e. the above reaction mixture) was 4:1. The results showed that the glucose conversion rate in this example was 98%, the yield of 5-hydroxymethylfurfural was 90%, and the purity was 98%. When the aforementioned ion pair bound homogeneous catalyst was recycled for 30 times, the yield of 5-hydroxymethylfurfural still maintained at 87%.

[0139] Example 21: A one-pot method for preparing 5-hydroxymethylfurfural provided in this example includes the following steps:

[0140] The homogeneous catalytic reaction system obtained in Example 7 was transferred to a closed reaction vessel, the reaction pressure was set to -0.08 MPa, the reaction temperature was set to 50°C, the reaction time was set to 240 min, after the reaction was completed, the pressure in the reaction vessel was restored to normal pressure conditions, water was added as a quenching agent to quench the reaction, the reaction mixture was analyzed by liquid chromatography, then dichloromethane was used as an extractant to extract 5-hydroxymethylfurfural by single-stage extraction, after the extraction was completed, the light phase and the heavy phase were separated; the light phase was separated by vacuum distillation to recover the extractant to obtain 5-hydroxymethylfurfural; the heavy phase was separated by vacuum distillation to separate the residual extractant and excess water to obtain a reusable ion pair bound homogeneous catalyst. The mass ratio of the quenching agent to the homogeneous catalytic reaction system in the above process was 4:1, and the mass ratio of the extractant to the total system after quenching (i.e. the above reaction mixture) was 3:1. The results showed that the glucose conversion rate in this example was 98%, the yield of 5-hydroxymethylfurfural was 92%, and the purity was 98%. When the aforementioned ion pair bound homogeneous catalyst was recycled for 30 times, the yield of 5-hydroxymethylfurfural still maintained at 92%.

[0141] Example 22: A one-pot method for preparing 5-hydroxymethylfurfural provided in this example includes the following steps:

[0142] The homogeneous catalytic reaction system obtained in Example 8 was transferred to a closed reaction container, the reaction pressure was set to -0.08 MPa, the reaction temperature was set to 80°C, the reaction time was set to 60 min, after the reaction was completed, the pressure in the reaction container was restored to normal pressure conditions, water was added as a quenching agent to quench the reaction, the reaction mixture was analyzed by liquid chromatography, then tetrahydrofuran was used as an extractant, 5-hydroxymethylfurfural was extracted by countercurrent extraction, after the extraction was completed, the light phase and the heavy phase were separated; the light phase was separated and the extractant was recovered by vacuum distillation, and 5-hydroxymethylfurfural was obtained; the heavy phase was separated and the residual extractant and excess water were removed by vacuum distillation, and the ion pair bound homogeneous catalyst that could be reused was obtained. The mass ratio of the quenching agent to the homogeneous catalytic reaction system in the above process was 1:1, and the mass ratio of the extractant to the total system after quenching (i.e. the above reaction mixture) was 2:1. The results showed that the sucrose conversion rate was 98%, the yield of 5-hydroxymethylfurfural was 90%, and the purity was 99%. When the ion pair bound homogeneous catalyst was recycled for 30 times, the yield of 5-hydroxymethylfurfural still maintained 90%.

[0143] Example 23: A one-pot method for preparing 5-hydroxymethylfurfural provided by the present embodiment includes the following steps:

[0144] The homogeneous catalytic reaction system obtained in Example 9 was transferred to a closed reaction container, the reaction pressure was set to -0.09 MPa, the reaction temperature was set to 200°C, the reaction time was set to 5 min, after the reaction was completed, the pressure in the reaction container was restored to normal pressure conditions, water was added as a quenching agent to quench the reaction, the reaction mixture was analyzed by liquid chromatography, then n-hexane was used as an extractant, 5-hydroxymethylfurfural was extracted by cross-flow extraction, after the extraction was completed, the light phase and the heavy phase were separated; the light phase was separated and the extractant was recovered by vacuum distillation, and 5-hydroxymethylfurfural was obtained; the heavy phase was separated and the residual extractant and excess water were removed by vacuum distillation, and the ion pair bound homogeneous catalyst that could be reused was obtained. The mass ratio of the quenching agent to the homogeneous catalytic reaction system in the above process was 3:1, and the mass ratio of the extractant to the total system after quenching (i.e. the above reaction mixture) was 4:1. The results showed that in the present embodiment, the glucose conversion rate was 98%, the yield of 5-hydroxymethylfurfural was 95%, and the purity was 98%. When the ion pair bound homogeneous catalyst was recycled for 30 times, the yield of 5-hydroxymethylfurfural still maintained 95%.

[0145] Example 24: A one-pot method for preparing 5-hydroxymethylfurfural provided by the present embodiment includes the following steps:

[0146] The homogeneous catalytic reaction system obtained in Example 10 was transferred to a closed reaction container, the reaction pressure was set to -0.1 MPa, the reaction temperature was set to 120°C, the reaction time was set to 30 min, after the reaction was completed, the pressure in the reaction container was restored to normal pressure conditions, water was added as a quenching agent to quench the reaction, the reaction mixture was analyzed by liquid chromatography, then n-hexane was used as an extractant, 5-hydroxymethylfurfural was extracted by cross-flow extraction, after the extraction was completed, the light phase and the heavy phase were separated; the light phase was separated by vacuum distillation to recover the extractant, and 5-hydroxymethylfurfural was obtained; the heavy phase was separated by vacuum distillation to separate the residual extractant and excess water, and the ion pair bound homogeneous catalyst that could be reused was obtained. The mass ratio of the quenching agent to the homogeneous catalytic reaction system in the above process was 1:1, and the mass ratio of the extractant to the total system after quenching (i.e. the above reaction mixture) was 2:1. The results showed that the glucose conversion rate in this example was 99%, the yield of 5-hydroxymethylfurfural was 95%, and the purity was 99%. When the aforementioned ion pair bound homogeneous catalyst was recycled for 30 times, the yield of 5-hydroxymethylfurfural still maintained at 90%.

[0147] Example 25: A one-pot method for preparing 5-hydroxymethylfurfural provided in this example includes the following steps:

[0148] The homogeneous catalytic reaction system obtained in Example 11 was transferred to a closed reaction container, the reaction pressure was set to -0.015 MPa, the reaction temperature was set to 100°C, the reaction time was set to 180 min, after the reaction was completed, the pressure in the reaction container was restored to normal pressure conditions, water was added as a quenching agent to quench the reaction, the reaction mixture was analyzed by liquid chromatography, then ethyl acetate was used as an extractant, 5-hydroxymethylfurfural was extracted by single-stage extraction, after the extraction was completed, the light phase and the heavy phase were separated; the light phase was separated by vacuum distillation to recover the extractant, and 5-hydroxymethylfurfural was obtained; the heavy phase was separated by vacuum distillation to separate the residual extractant and excess water, and the ion pair bound homogeneous catalyst that could be reused was obtained. The mass ratio of the quenching agent to the homogeneous catalytic reaction system in the above process was 1:1, and the mass ratio of the extractant to the total system after quenching (i.e. the above reaction mixture) was 1:1. The results showed that the glucose conversion rate in this example was 98%, the yield of 5-hydroxymethylfurfural was 80%, and the purity was 99%. When the aforementioned ion pair bound homogeneous catalyst was recycled for 30 times, the yield of 5-hydroxymethylfurfural still maintained at 80%.

[0149] Example 26: A one-pot method for preparing 5-hydroxymethylfurfural provided in this example includes the following steps:

[0150] The homogeneous catalytic reaction system obtained in Example 12 was transferred into a closed reaction container, the reaction pressure was set to be -0.08 MPa, the reaction temperature was set to be 100°C, the reaction time was set to be 60 min, after the reaction was completed, the pressure in the reaction container was restored to normal pressure condition, water was added as a quenching agent to quench the reaction, the reaction mixture was analyzed by liquid chromatography, then tetrahydrofuran was used as an extractant, 5-hydroxymethylfurfural was extracted by using cross-flow extraction, after the extraction was completed, the light phase and the heavy phase were separated; the extractant was separated and recovered from the light phase by vacuum distillation, 5-hydroxymethylfurfural was obtained; the residual extractant and excess water were separated from the heavy phase by vacuum distillation, and the ion pair bound homogeneous catalyst which could be reused was obtained. The mass ratio of the quenching agent to the homogeneous catalytic reaction system in the above process was 3:1, and the mass ratio of the extractant to the total system after quenching (i.e. the above reaction mixture) was 4:1. The results showed that in this example, the conversion rate of fructose was 99%, the yield of 5-hydroxymethylfurfural was 90%, and the purity was 98%. When the ion pair bound homogeneous catalyst was recycled for 30 times, the yield of 5-hydroxymethylfurfural still maintained at 90%.

[0151] Example 27: A one-pot method for preparing 5-hydroxymethylfurfural provided in this example includes the following steps:

[0152] The homogeneous catalytic reaction system obtained in Example 13 was transferred into a closed reaction container, the reaction pressure was set to be -0.05 MPa, the reaction temperature was set to be 100°C, the reaction time was set to be 120 min, after the reaction was completed, the pressure in the reaction container was restored to normal pressure condition, water was added as a quenching agent to quench the reaction, the reaction mixture was analyzed by liquid chromatography, then cyclohexane was used as an extractant, 5-hydroxymethylfurfural was extracted by using countercurrent extraction, after the extraction was completed, the light phase and the heavy phase were separated; the extractant was separated and recovered from the light phase by vacuum distillation, 5-hydroxymethylfurfural was obtained; the residual extractant and excess water were separated from the heavy phase by vacuum distillation, and the ion pair bound homogeneous catalyst which could be reused was obtained. The mass ratio of the quenching agent to the homogeneous catalytic reaction system in the above process was 4:1, and the mass ratio of the extractant to the total system after quenching (i.e. the above reaction mixture) was 5:1. The results showed that in this example, the conversion rate of fructose was 99%, the yield of 5-hydroxymethylfurfural was 95%, and the purity was 99%. When the ion pair bound homogeneous catalyst was recycled for 30 times, the yield of 5-hydroxymethylfurfural still maintained at 95%.

[0153] Example 28: A one-pot method for preparing 5-hydroxymethylfurfural provided in this example includes the following steps:

[0154] The homogeneous catalytic reaction system obtained in Example 14 was transferred into a closed reaction vessel, and the reaction pressure was set to -0.09 MPa, the reaction temperature was set to 120°C, and the reaction time was set to 60 min. After the reaction was completed, the pressure in the reaction vessel was returned to normal pressure, water was added as a quenching agent to quench the reaction, and the reaction mixture was analyzed by liquid chromatography. Then, 5-hydroxymethylfurfural was extracted using tetrahydrofuran as an extractant by countercurrent extraction. After the extraction was completed, the light phase and the heavy phase were separated. The light phase was separated and the extractant was recovered by vacuum distillation, and 5-hydroxymethylfurfural was obtained. The heavy phase was separated and the residual extractant and excess water were removed by vacuum distillation, and the ion-pair bound homogeneous catalyst was obtained. The mass ratio of the quenching agent to the homogeneous catalytic reaction system was 3:1, and the mass ratio of the extractant to the total system after quenching (i.e., the reaction mixture) was 3:1. The results showed that the glucose conversion rate was 99%, the yield of 5-hydroxymethylfurfural was 96%, and the purity was 99% in this example. When the ion-pair bound homogeneous catalyst was recycled for 30 times, the yield of 5-hydroxymethylfurfural was still maintained at 96%.

[0155] Comparative Example 1: This comparative example provides a method for preparing 5-hydroxymethylfurfural, which is basically the same as Example 15, except that the composition of the homogeneous catalytic composition is different. Specifically, in this comparative example, the methanesulfonic acid in the homogeneous catalytic reaction system of Example 15 is replaced with an equal amount of a heterogeneous sulfonic acid resin (Amberlyst-15). The results showed that the glucose conversion rate was 80%, the yield of 5-hydroxymethylfurfural was 71%, and the recycling effect of the homogeneous catalytic composition was not ideal. After three recycles, the glucose conversion rate decreased from the initial 80% to 27%.

[0156] Comparative Example 2: This comparative example provides a method for preparing 5-hydroxymethylfurfural, which is basically the same as Example 15, except that the composition of the homogeneous catalytic composition is different. Specifically, in this comparative example, the tetraethylammonium bromide in the homogeneous catalytic reaction system of Example 15 is replaced with an equal amount of DMSO. The results showed that the glucose conversion rate was 99%, and the yield of 5-hydroxymethylfurfural before separation was 85%. The separation of 5-hydroxymethylfurfural cannot be directly extracted, but must be distilled under reduced pressure to remove water and DMSO. Due to the high temperature, 5-hydroxymethylfurfural is destroyed, resulting in a yield of 56% of 5-hydroxymethylfurfural after separation, and the homogeneous acid cannot be recovered.

[0157] Comparative Example 3: This comparative example provides a method for preparing 5-hydroxymethylfurfural, which is basically the same as Example 15, except that the reaction pressure and the reaction time are different. Specifically, in this comparative example, the reaction pressure is adjusted to normal pressure, and the reaction time is increased to 120 min. The results showed that the glucose conversion rate was 87%, and the yield of 5-hydroxymethylfurfural was 61%.

[0158] Comparative Example 4: This comparative example provides a method for preparing 5- hydroxymethylfurfural which is essentially the same as Example 15, except that no quenching agent is used, and the reaction system is allowed to cool naturally after the reaction is complete. The results show that the glucose conversion is 98% and the yield of 5- hydroxymethylfurfural is 45% in this comparative example.

[0159] Comparative Example 5: This comparative example provides a method for preparing 5- hydroxymethylfurfural which is essentially the same as Example 15, except that no quenching agent is used, and the reaction system is forced to convective cooling after the reaction is complete. The results show that the glucose conversion is 99% and the yield of 5- hydroxymethylfurfural is 63% in this comparative example.

[0160] Comparative Example 6: This comparative example provides a method for preparing 5- hydroxymethylfurfural which is essentially the same as Example 15, except that during the preparation of the homogeneous catalytic reaction system provided in Example 1, the tetraethylammonium bromide, methanesulfonic acid and water are not mixed uniformly in advance, but the tetraethylammonium bromide, methanesulfonic acid, CrCl3, water and glucose are mixed directly. The results show that the glucose conversion is 89% and the yield of 5- hydroxymethylfurfural is 78% in this comparative example.

[0161] Comparative Example 7: This comparative example provides a method for preparing 5- hydroxymethylfurfural which is essentially the same as Example 15, except that the composition of the homogeneous catalytic composition is different. Specifically, CrCl3 in the homogeneous catalytic reaction system of Example 15 is omitted in this comparative example. The results show that the glucose conversion is 99% and the yield of 5- hydroxymethylfurfural is 25%, and a large amount of solid humin is produced, which causes the solvent to be unable to be further extracted and separated, specifically, the organic phase and the aqueous phase do not separate after the addition of the quenching agent water and the extraction agent ethyl acetate.

[0162] Comparative Example 8: This comparative example provides a method for preparing 5- hydroxymethylfurfural which is essentially the same as Example 15, except that the composition of the homogeneous catalytic composition is different. Specifically, the mass ratio of methanesulfonic acid to CrCl3 in this comparative example is 1:0.8. The results show that the glucose conversion is 99% and the yield of 5- hydroxymethylfurfural is 65%, and a large amount of solid humin is produced, which makes it difficult to separate 5- hydroxymethylfurfural by extraction, and the organic phase and the aqueous phase are difficult to separate, and need to be left to stand for 24 hours to separate. The yield of 5- hydroxymethylfurfural further decreases to 44% after the solvent is reused.

[0163] Comparative Example 9: This comparative example provides a method for preparing 5-hydroxymethylfurfural, which is basically the same as Example 15, except that the composition of the homogeneous catalytic composition is different. Specifically, the mass ratio of methyl sulfonic acid to CrCl3 in this comparative example is 1:25. The results show that the conversion rate of glucose is 98%, the yield of 5-hydroxymethylfurfural is 56%, the yield can be up to 78% by extending the reaction time, 5-hydroxymethylfurfural can be separated by extraction, but the number of times of reuse of the homogeneous catalytic composition is reduced, and the yield of 5-hydroxymethylfurfural is reduced to 59% after 5 times, and the heavy phase and the light phase are difficult to separate, and the solvent cannot be further reused.

[0164] In the method for synthesizing 5-hydroxymethylfurfural provided in the above examples of the present application, a quaternary ammonium salt, a six-carbon sugar, water, a homogeneous Lewis acid, and a homogeneous acid complex system are used to realize one-pot efficient preparation of 5-hydroxymethylfurfural through series of sugar isomerization reaction and fructose dehydration reaction, water-assisted solubilization of quaternary ammonium salt and six-carbon sugar to form a eutectic system, and at the same time, the stable homogeneous catalytic reaction system is formed by the ion pair of "quaternary ammonium salt binding homogeneous acid", in which the conversion rate of six-carbon sugar is >98%, the yield of target product is >75%, the purity of target product is >97% through rapid quenching and extraction separation, and the quaternary ammonium salt and the homogeneous acid can be recycled. The synthesis method of the present application can accelerate the industrial production of 5-hydroxymethylfurfural, and has a broad application prospect.

[0165] In addition, it should be noted that each specific technical feature described in the above specific embodiments can be combined in any manner without contradiction, and in order to avoid unnecessary repetition, various possible combinations are not described again in the present application.

[0166] Furthermore, various different embodiments of the present application can be combined in any manner, as long as the idea of the present application is not violated, and they should also be considered as disclosed in the present application.

Claims

1. A homogeneous catalytic composition characterized in that, comprising a homogeneous catalyst, a quaternary ammonium salt, and water; the homogeneous catalyst comprising a homogeneous acid and a homogeneous Lewis acid; the quaternary ammonium salt being capable of forming an ion pair binding system with the homogeneous acid and the homogeneous Lewis acid.

2. The homogeneous catalytic composition according to claim 1, characterized in that: The mass ratio of the quaternary ammonium salt, the homogeneous catalyst and water is 20-80: 0.1-5: 4-20; wherein the homogeneous catalyst is a Lewis acid The mass ratio of the acid and the homogeneous Lewis acid is 1: 1-1: 20; and / or the quaternary ammonium salt comprises a substance of the general formula R4NX, wherein the hydrocarbon radical R comprises a substituted and / or unsubstituted alkyl and / or aryl radical and X comprises F - , Cl - , Br - , I - , NO2 - , NO3 - or SO4 2- ; and / or, the homogeneous phase The acid includes one or more of any combination of HF, HCl, HBr, HI, H2SO4, HNO3, trifluoromethanesulfonic acid, benzene sulfonic acid, methanesulfonic acid, p-toluenesulfonic acid, and dodecyl benzene sulfonic acid; And / or, the homogeneous Lewis acid includes a metal salt.

3. The homogeneous catalytic composition of claim 2, wherein: homogeneous The mass ratio of the acid and the homogeneous Lewis acid is 1:5 to 1:

20.

4. The homogeneous catalytic composition of claim 2, wherein: The cation in the metal salt comprises one or more of Mg 2+ , Ca 2+ , Al 3+ , Sn 2+ , Sn 4+ , Fe 2+ , Fe 3+ , Ni 2+ , Co 2+ , Cu 2+ , Cu + , Cr 3+ , Cr 2+ , Zr 4+ and the anion comprises one or more of F - , Cl - , Br - , I - , SO4 2- , SO3 2- , HSO3 - , NO3 - , CO3 2- , HCO3 - , PO4 3- , HPO3 2- , H2PO3 - , C2O4 2- , CH3COO - .

5. A process for the one-pot preparation of 5-hydroxymethylfurfural, characterized in that, The method comprises: reacting a homogeneous catalytic reaction system comprising a six-carbon sugar and the homogeneous catalytic composition according to any one of claims 1-4, and then quenching the reaction with a quenching agent, and separating the 5-hydroxymethylfurfural and the homogeneous catalytic composition from the obtained reaction mixture.

6. The process for one-pot preparation of 5-hydroxymethylfurfural according to claim 5, characterized by: The homogeneous catalytic reaction system comprises the six-carbon sugar, the quaternary ammonium salt, the water, and the homogeneous catalyst in a mass ratio of 15-50:20-80:4-20:0.1-5; And / or, the six-carbon sugar includes one or more of any combination of glucose, fructose, galactose, mannose, sorbose, sucrose, inulin, hydrolyzed starch, cellulose, and algal polysaccharide.

7. The process for one-pot preparation of 5-hydroxymethylfurfural according to claim 6, characterized by: The homogeneous catalytic reaction system comprises 20wt%-50wt% of the six-carbon sugar and 0.1wt%-5wt% of the homogeneous catalyst; And / or, the six-carbon sugar includes glucose.

8. The method for preparing 5-hydroxymethylfurfural in one pot according to claim 5, wherein: The temperature of the reaction is 50-200°C; And / or, the reaction is carried out under reduced pressure, and the pressure of the reaction is -0.1MPa to -0.015MPa, And / or, the reaction time is 5min-240min; And / or, the pH value of the reaction system is maintained at 0-1 during the reaction.

9. The method for preparing 5-hydroxymethylfurfural in one pot according to claim 8, wherein: The temperature of the reaction is 60-120°C; And / or, the pressure of the reaction is -0.1MPa to -0.075MPa.

10. The process for one pot preparation of 5-hydroxymethylfurfural as claimed in claim 5 wherein, Specifically comprising: at least a quaternary ammonium salt, a homogeneous homogeneously mixing the acid, the homogeneous Lewis acid, and the water to obtain the homogeneous catalytic composition; Then, uniformly mixing the homogeneous catalytic composition and the six-carbon sugar to obtain the homogeneous catalytic reaction system.

11. The method of one-pot preparation of 5-hydroxymethylfurfural according to claim 10, characterized by, The homogeneous catalytic composition and / or the homogeneous catalytic reaction system is prepared at a temperature of 20-100°C.

12. The method of one pot preparation of 5-hydroxymethylfurfural as claimed in claim 5 wherein, Specifically comprising: After the reaction, a quenching agent is added to the reaction system to quench the reaction, thereby obtaining the reaction mixture.

13. The method of one-pot preparation of 5-hydroxymethylfurfural according to claim 12, characterized by, The quenching agent includes water; and / or, the amount of the quenching agent added is 1-5 times the total mass of the reaction system; and / or, the quenching agent is added after the reaction is completed and the reaction system returns to normal pressure.

14. The method of one pot preparation of 5-hydroxymethylfurfural as claimed in claim 5 wherein, Specifically comprising: extracting the reaction mixture with an extractant to obtain a light phase and a heavy phase; separating the 5-hydroxymethylfurfural from at least the light phase; and, recovering the homogeneous catalyst from at least the heavy phase.

15. The method of one-pot preparation of 5-hydroxymethylfurfural according to claim 14, characterized by, The extractant comprises an organic solvent, which comprises any combination of one or more of petroleum ether, cyclohexane, n-hexane, diethyl ether, ethyl acetate, acetonitrile, dichloroethane, and tetrahydrofuran; and / or, the extractant is added in an amount of 1-5 times the mass of the reaction mixture; and / or, the extraction is performed by one of single-stage extraction, multi-stage countercurrent extraction, or multi-stage crossflow extraction.

16. The method of one pot preparation of 5-hydroxymethylfurfural as claimed in claim 5 wherein, Specifically comprising: The extractant is recovered from the light phase by at least reduced pressure distillation, and 5-hydroxymethylfurfural is obtained. And / or, the extractant and part of the water in the heavy phase are separated by at least reduced pressure distillation, and the homogeneous catalytic composition is obtained.

17. The method of one-pot preparation of 5-hydroxymethylfurfural according to any one of claims 5-16, characterized in that, Specifically comprising: quaternary ammonium salt, homogeneous phase The acid, the homogeneous Lewis acid, and the water are uniformly mixed to obtain a homogeneous catalytic composition, and then the homogeneous catalytic composition is uniformly mixed with a six-carbon sugar to obtain the homogeneous catalytic reaction system; The homogeneous catalytic reaction system is subjected to the reaction in a sealed reaction solvent under reduced pressure; After the reaction is completed, the reaction system is returned to normal pressure, a quenching agent is added to quench the reaction, and then an extractant is used to extract the obtained reaction mixture to obtain a light phase and a heavy phase; The extractant is recovered from the light phase, and 5-hydroxymethylfurfural is obtained. The extractant and part of the water in the heavy phase are separated, and the homogeneous catalytic composition is recovered; The recovered homogeneous catalytic composition is uniformly mixed with a six-carbon sugar to form a homogeneous catalytic reaction system again.

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