WO2021046996A1

WO2021046996A1 - Method for improving synthesis efficiency of 5-hydroxymethylfurfural

Info

Publication number: WO2021046996A1
Application number: PCT/CN2019/115599
Authority: WO
Inventors: 黄家辉; 徐吉磊; 商雪航
Original assignee: 中国科学院大连化学物理研究所
Priority date: 2019-09-11
Filing date: 2019-11-05
Publication date: 2021-03-18

Abstract

The present invention provides a method for improving synthesis efficiency of 5-hydroxymethylfurfural. A synthesis system of 5-hydroxymethylfurfural comprises an organic solvent. In a reaction process, the organic solvent is first preheated to a reaction temperature, and then pumped into a reactor together with a water phase. In this way, the present invention can achieve rapid temperature rise, shortening the reaction time, avoiding the occurrence of side reactions during the process of rising from room temperature to reaction temperature, reducing the hydrolysis of 5-hydroxymethylfurfural, and improving the yield of 5-hydroxymethylfurfural.

Description

Untitled

A method for improving the synthesis efficiency of 5-hydroxymethyl furfural

Technical field

The invention belongs to the field of 5-hydroxymethyl furfural synthesis, and specifically relates to a method for synthesizing 5-hydroxymethyl furfural.

Background technique

5-Hydroxymethylfurfural (HMF) is an important chemical raw material and a raw material for the synthesis of 2,5-furandicarboxylic acid (FDCA). Although it has been more than 120 years since the discovery of 5-hydroxymethyl furfural, it has not been produced on a large scale. The main reason is that there are great difficulties in its preparation and separation. 5-Hydroxymethylfurfural is mainly obtained through the dehydration reaction of six carbon sugars such as glucose and fructose. Among them, it is the easiest to obtain from fructose dehydration, which is also the basis for preparing 5-hydroxymethylfurfural from other sugar compounds. At present, the method for preparing 5-hydroxymethyl furfural from fructose mainly consists of the following systems: pure water system, organic system, water-oil two-phase system, and ionic liquid system. Although the pure water system can increase the initial concentration of fructose, the resulting 5-hydroxymethylfurfural will rehydrate with water to generate levulinic acid and formic acid, making the final 5-hydroxymethylfurfural yield very low. A large number of experimental studies have proved that the selectivity of 5-hydroxymethyl furfural is higher in organic solvents with high boiling points. For example, the selectivity of 5-hydroxymethyl furfural in DMSO can reach more than 99%. However, how to separate 5-hydroxymethyl furfural from high boiling point solvents is a very difficult problem. Even the use of vacuum distillation will cause very large product loss. In recent years, ionic liquid systems have attracted much attention. In ionic liquids, 5-hydroxymethylfurfural can be obtained almost quantitatively from fructose. However, the price of ionic liquids is relatively high, which is not conducive to mass use. Moreover, the separation of 5-hydroxymethyl furfural from the ionic liquid requires an extraction method, which consumes a large amount of low boiling point solvent and consumes a large amount of energy. Therefore, the water-oil two-phase system, especially the reaction system composed of water and a low boiling point organic solvent, is the most promising system for the production of 5-hydroxymethyl furfural. Dumesic et al. (Science, 2006; Top Catal, 2009) have done a lot of research in this area and achieved good results. In the water-organic solvent system, the fructose dehydration reaction occurs in the water phase, and then it is extracted in situ. In the organic phase, the hydration reaction of 5-hydroxymethyl furfural can be effectively avoided within a certain period of time, and the selectivity of 5-hydroxymethyl furfural can be improved. However, if the reaction time is longer, the 5-hydroxymethylfurfural extracted into the organic layer will be back-extracted into the water phase, and hydration reaction occurs in the water phase to generate levulinic acid and formic acid, 5-hydroxymethylfurfural The selectivity will also decrease. In summary, in the prior art, since the solvent needs a long process from room temperature to high temperature, many side reactions will occur during this period, thereby greatly reducing the yield of 5-hydroxymethyl furfural.

Summary of the invention

Based on the above background technology, the purpose of the present invention is to provide a method for efficiently synthesizing 5-hydroxymethyl furfural. The present invention can greatly shorten the reaction time through preheating, thereby solving the problem of side effects caused by the long reaction time in the prior art. Respond to this problem. Take the following technical solutions:

The present invention provides a method for improving the synthesis efficiency of 5-hydroxymethyl furfural. The reaction system of the method includes an organic solvent. The organic solvent is preheated to the reaction temperature before the reaction, that is, before the organic solvent and the reactants are mixed and reacted. Preheat to reaction temperature.

Based on the above technical solution, the reaction raw material is a six-carbon sugar, and the six-carbon sugar is fructose, glucose, mannose or galactose.

Based on the above technical solution, the reaction system further includes a saturated inorganic salt solution.

Based on the above technical solution, the organic solvent is tetrahydrofuran, n-butanol, 2-butanol, butanone, methyl isobutyl ketone, 2-methyltetrahydrofuran; the inorganic salt is potassium chloride, sodium chloride, Sodium sulfate, potassium sulfate, potassium bromide, sodium bromide, potassium iodide, sodium iodide, lithium chloride.

Based on the above technical solution, the reactor is a static mixer or a high-pressure reactor; the flow rate of the solution in the static mixer is 0.1-5 m/s, preferably 1-3 m/s; the reaction tube of the static mixer The length is 10-200m.

Based on the above technical solution, the catalyst of the method is an organic acid, an inorganic acid, an acidic ionic liquid or a Lewis acid.

Based on the above technical solution, the inorganic acid is sulfuric acid, hydrochloric acid, phosphoric acid, and nitric acid; the organic acid is formic acid, acetic acid, and propionic acid; the Lewis acid is aluminum chloride, ferric chloride, aluminum sulfate, aluminum nitrate, iron nitrate, and chromium nitrate. Chromium chloride; acidic ionic liquids are 1-(3-sulfopropyl)-3-methylimidazole hydrogensulfate, 1-(3-sulfopropyl)-3-methylimidazole chloride, 1-(3-sulfopropyl)-3-methylimidazole bromide, 1-(3-sulfopropyl)-3-methylimidazole acetate, 1-(3-sulfopropyl) Group)-3-methylimidazole hexafluorophosphate, 1-(3-sulfopropyl)-3-methylimidazole tetrafluoroborate, 1-(3-sulfopropyl)-3- Methylimidazole nitrate, 1-(3-sulfopropyl)-3-methylimidazole dihydrogen phosphate, 1-(4-sulfobutyl)-3-methylimidazole hydrogensulfate, 1 -(4-sulfobutyl)-3-methylimidazole chloride, 1-(4-sulfobutyl)-3-methylimidazole bromide, 1-(4-sulfobutyl) -3-Methylimidazole acetate, 1-(4-sulfobutyl)-3-methylimidazole hexafluorophosphate, 1-(4-sulfobutyl)-3-methylimidazole Fluoroborate, 1-(4-sulfobutyl)-3-methylimidazole nitrate, 1-(4-sulfobutyl)-3-methylimidazole dihydrogen phosphate, the acid The ionic liquid is preferably 1-(3-sulfopropyl)-3-methylimidazole hydrogensulfate or 1-(4-sulfobutyl)-3-methylimidazole hydrogensulfate.

Based on the above technical solutions,

When the reactor is a static mixer, the method includes the following steps:

(1) Mixing a saturated inorganic salt solution with raw materials to obtain a raw material solution, adding a catalyst to the raw material solution to obtain a reaction solution; the mass fraction of the raw material in the raw material solution is 5-60 wt%; in the reaction solution, the catalyst The mass fraction of 0.1%-5%;

(2) The organic solvent preheated to the reaction temperature and the reaction solution are respectively injected into the static mixer through a conveying device, and the reaction is controlled at 160-240°C;

(3) Cool the reaction liquid effluent of the static mixer in step (2), stand still for layering, and separate the liquids, and then distill the upper organic layer under reduced pressure to obtain the 5-hydroxymethyl furfural; the upper layer is organic Phase, the lower layer is saturated inorganic brine phase;

When the reactor is an autoclave, the method includes the following steps:

(1) Dissolve the raw materials and the catalyst in a saturated aqueous solution of inorganic salt to obtain a reactant solution, and place the organic solvent in an autoclave to preheat to the reaction temperature;

(2) Add the reactant solution to the reactor and treat it at 80-240°C for 1 min-12h; the mass concentration of the raw material in the reactant solution is 5%-60%, and the amount of catalyst used is 0.01% to 5% of the mass of the reactant solution, and the mass ratio of the organic solvent to the reactant solution is 0.5-50:1;

(3) Cool down, stand still for layering and liquid separation, and then distill the upper organic layer under reduced pressure to obtain the 5-hydroxymethyl furfural.

Based on the above technical solution, when the reactor is a static mixer, the volume ratio of the organic solvent and the reactant solution described in step (2) is 1:1-20:1; the saturated inorganic brine phase in step (3) is used Extraction with an equal volume of organic solvent, the extracted organic phase layer is combined with the organic phase layer described in step (3) and distilled under reduced pressure to obtain the 5-hydroxymethyl furfural and recover the organic solvent; the extracted saturated inorganic brine layer Recycle after adding raw materials.

Based on the above technical solution, when the reactor is an autoclave, the lower layer in step (3) is a saturated inorganic salt water layer, and the saturated inorganic salt water layer is extracted three times with the same quality organic phase extractant, which is the same as step (3) The upper organic phases in the upper layer are combined and distilled under reduced pressure to obtain the 5-hydroxymethyl furfural; the organic phase extractant is tetrahydrofuran, methyl isobutyl ketone, butanone, n-butanol, isobutanol or 2 -Methyltetrahydrofuran.

Based on the above technical solution, the flow rate of the solution in the static mixer is preferably 1 m/s.

The invention also provides a method for improving the synthesis efficiency of 5-hydroxymethyl furfural. The raw material is fructose, the reaction system is a saturated inorganic salt solution-organic solvent system, and the reactor is a static mixer.

In the technical solution, the flow rate of the solution in the static mixer is 0.1-5 m/s; the catalyst is an organic acid, an inorganic acid, an acidic ionic liquid or a Lewis acid.

In the technical solution, the organic solvent is tetrahydrofuran, n-butanol, 2-butanol, butanone, methyl isobutyl ketone, and 2-methyltetrahydrofuran.

In the technical solution, the inorganic salt is potassium chloride, sodium chloride, sodium sulfate, potassium sulfate, potassium bromide, sodium bromide, potassium iodide, sodium iodide, and lithium chloride.

In the technical solution, the length of the reaction tube of the static mixer is 10-200m; preferably 60m.

The method includes the following steps:

(1) Mixing a saturated inorganic salt solution with fructose to obtain a fructose solution, adding a catalyst to the fructose solution to obtain a reaction solution; in the fructose solution, the mass fraction of fructose is 5-60 wt%;

(3) Cool the reaction liquid effluent of the static mixer in step (2), stand still for layering, and separate the liquids, and then distill the upper organic layer under reduced pressure to obtain the 5-hydroxymethyl furfural; the upper layer is organic The lower layer is the saturated inorganic brine phase.

In the technical solution, the mass fraction of the catalyst in the reaction solution is 0.1% to 5%, and preferably the mass fraction of the catalyst is 0.1% of the reaction solution.

In the technical solution, the catalyst is an organic acid, an inorganic acid, an acidic ionic liquid or a Lewis acid. Preferably, the inorganic acid is sulfuric acid, hydrochloric acid, phosphoric acid, and nitric acid; the organic acid is formic acid, acetic acid, and propionic acid; the Lewis acid is aluminum chloride, iron chloride, aluminum sulfate, aluminum nitrate, iron nitrate, Chromium nitrate, chromium chloride; the acidic ionic liquid is 1-(3-sulfopropyl)-3-methylimidazole hydrogensulfate, 1-(3-sulfopropyl)-3-methyl Imidazole chloride salt, 1-(3-sulfopropyl)-3-methylimidazole bromide, 1-(3-sulfopropyl)-3-methylimidazole acetate, 1-(3- Sulfonic acid propyl)-3-methylimidazole hexafluorophosphate, 1-(3-sulfonic acid propyl)-3-methylimidazole tetrafluoroborate, 1-(3-sulfonic acid propyl) )-3-Methylimidazole nitrate, 1-(3-sulfopropyl)-3-methylimidazole dihydrogen phosphate, 1-(4-sulfobutyl)-3-methylimidazole sulfuric acid Hydrogen salt, 1-(4-sulfobutyl)-3-methylimidazole chloride, 1-(4-sulfobutyl)-3-methylimidazole bromide, 1-(4-sulfonic acid Butyl)-3-methylimidazole acetate, 1-(4-sulfobutyl)-3-methylimidazole hexafluorophosphate, 1-(4-sulfobutyl)-3- Methylimidazole tetrafluoroborate, 1-(4-sulfobutyl)-3-methylimidazole nitrate, 1-(4-sulfobutyl)-3-methylimidazole dihydrogen phosphate .

In the technical solution, the saturated inorganic brine phase in step (3) is extracted with an equal volume of organic solvent, and the extracted organic phase layer is combined with the organic phase layer described in step (3) by vacuum distillation to obtain the 5 -Hydroxymethylfurfural and recover the organic solvent; the saturated inorganic brine layer after extraction is supplemented with fructose and recycled.

In the technical solution, the flow rate of the solution in the static mixer is preferably 1-3 m/s; the flow rate of the solution in the static mixer is further preferably 1 m/s.

In the technical solution, the volume ratio of the organic solvent and the reactant solution described in step (2) is 1:1-20:1.

Based on the above technical solution, the mass fraction of the catalyst is 0.1% of the reaction solution.

Based on the above technical solution, the saturated sodium chloride aqueous phase in step (3) is extracted with an equal volume of organic solvent (tetrahydrofuran), and the extracted organic phase layer is combined with the organic phase layer described in step (3) by vacuum distillation, The 5-hydroxymethyl furfural is obtained and the organic solvent is recovered; the extracted saturated sodium chloride aqueous layer is supplemented with fructose and then recycled.

Based on the above technical solution, the volume ratio of the organic solvent and the reactant solution described in step (2) is 1:1-20:1.

Beneficial effect

(1) In the synthesis method of the present invention, the organic phase is first preheated to the reaction temperature, and then fed into the reactor together with the water phase, which can quickly increase the temperature and shorten the reaction time, and avoid rising from room temperature to reaction. The occurrence of side reactions during the temperature process reduces the hydrolysis of 5-hydroxymethyl furfural and increases the yield of 5-hydroxymethyl furfural.

(2) The extractant used in the present invention is less toxic and less harmful to the environment. It uses a high-concentration saturated inorganic salt solution to increase the distribution coefficient of the product in the organic-water phase, while ensuring the formation of a two-phase system. , Is conducive to the transfer of the product to the organic phase.

(3) The present invention uses a static mixer. Compared with the traditional high-pressure reactor, the present invention controls the flow rate of the reaction solution in the static mixer and the reaction time, so that the reaction time is greatly reduced, so that the reactants stay in the system. The time is reduced, the by-products are reduced, and the product yield is 61-99%. Compared with a tank reactor, the static mixer used in the present invention is a reactor that can be continuously produced. Raw materials can be continuously added to the reactor from the front end of the reactor, and the reacted liquid can be continuously output from the back end of the reactor. , And there will be no back-mixing phenomenon between the reacted liquid and the newly added raw materials, and there is no need to go through the process of cooling, opening the kettle, etc., which can improve production efficiency.

detailed description

The high-pressure reactor and static mixer used in the present invention are generally commercially available or commercial high-pressure reactors or static mixers.

Example 1

A 10% fructose solution with a mass fraction of 10% was prepared using saturated brine, and a sulfuric acid catalyst with a mass fraction of 1/1000 was added. The tetrahydrofuran preheated to 200℃ and the fructose solution containing the catalyst are injected into the static mixer (the reaction tube length is 60m) that has been preheated to 200℃ through two constant flow pumps A and B at a flow rate of 1m/s. The volume ratio of tetrahydrofuran and fructose solution is 3:1. After passing through the static mixer, the reaction liquid enters a liquid storage tank placed in an ice water bath for cooling and stratification. The upper layer is the organic phase, and the lower layer is the saturated brine phase. After liquid separation, the saturated brine layer was extracted with an equal volume of tetrahydrofuran, combined with the upper organic phase, and then distilled under reduced pressure. The yield of 5-hydroxymethyl furfural was 99%. The recovered tetrahydrofuran was directly recycled. The saturated brine The layer is recycled after adding raw materials.

Example 2

A 10% fructose solution with a mass fraction of 10% was prepared using saturated brine, and an aluminum chloride catalyst with a mass fraction of 1/1000 was added. The tetrahydrofuran preheated to 200℃ and the fructose solution containing the catalyst are injected into the static mixer (the reaction tube length is 60m) that has been preheated to 200℃ through two constant flow pumps A and B at a flow rate of 1m/s. The volume ratio of tetrahydrofuran and fructose solution is 3:1. After passing through the static mixer, the reaction liquid enters a liquid storage tank placed in an ice water bath for cooling and stratification. The upper layer is the organic phase, and the lower layer is the saturated brine phase. After liquid separation, the saturated brine layer was extracted with an equal volume of tetrahydrofuran, combined with the upper organic phase, and then distilled under reduced pressure. The yield of 5-hydroxymethyl furfural was 79%. The recovered tetrahydrofuran was directly recycled. The saturated brine The layer is recycled after adding raw materials.

Example 3

A 10% fructose solution with a mass fraction of 10% was prepared using saturated brine, and a sulfuric acid catalyst with a mass fraction of 1/1000 was added. The tetrahydrofuran preheated to 160℃ and the fructose solution containing the catalyst are respectively injected into the static mixer (the reaction tube length is 60m) which has been preheated to 160℃ through two constant flow pumps A and B at a flow rate of 1m/s. The volume ratio of tetrahydrofuran and fructose solution is 3:1. After passing through the static mixer, the reaction liquid enters a liquid storage tank placed in an ice water bath for cooling and stratification. The upper layer is the organic phase, and the lower layer is the saturated brine phase. After liquid separation, the saturated brine layer was extracted with an equal volume of tetrahydrofuran, combined with the upper organic phase, and then distilled under reduced pressure. The yield of 5-hydroxymethyl furfural was 75%. The recovered tetrahydrofuran was directly recycled. The saturated brine The layer is recycled after adding raw materials.

Example 4

A 10% fructose solution with a mass fraction of 10% was prepared using saturated brine, and a sulfuric acid catalyst with a mass fraction of 1/1000 was added. The tetrahydrofuran preheated to 240℃ and the fructose solution containing the catalyst are respectively injected into the static mixer (the reaction tube length is 60m) that has been preheated to 240℃ through two constant flow pumps A and B at a flow rate of 1m/s. The volume ratio of tetrahydrofuran and fructose solution is 3:1. After passing through the static mixer, the reaction liquid enters a liquid storage tank placed in an ice water bath for cooling and stratification. The upper layer is the organic phase, and the lower layer is the saturated brine phase. After liquid separation, the saturated brine layer was extracted with an equal volume of tetrahydrofuran, combined with the upper organic phase, and then distilled under reduced pressure. The yield of 5-hydroxymethyl furfural was 89%. The recovered tetrahydrofuran was directly recycled. The saturated brine The layer is recycled after adding raw materials.

Example 5

A fructose solution with a mass fraction of 10% was prepared using saturated brine, and a formic acid catalyst with a mass fraction of 1/1000 was added. The tetrahydrofuran preheated to 200℃ and the fructose solution containing the catalyst are injected into the static mixer (the reaction tube length is 60m) that has been preheated to 200℃ through two constant flow pumps A and B at a flow rate of 1m/s. The volume ratio of tetrahydrofuran and fructose solution is 3:1. After passing through the static mixer, the reaction liquid enters a liquid storage tank placed in an ice water bath for cooling and stratification. The upper layer is the organic phase, and the lower layer is the saturated brine phase. After liquid separation, the saturated brine layer was extracted with an equal volume of tetrahydrofuran, combined with the upper organic phase, and then distilled under reduced pressure to obtain 5-hydroxymethyl furfural with a yield of 70%. The recovered tetrahydrofuran was directly recycled and the saturated brine The layer is recycled after adding raw materials.

Example 6

A 10% fructose solution with a mass fraction of 10% was prepared using saturated brine, and a 1-(3-sulfonylpropyl)-3-methylimidazole hydrogensulfate catalyst with a mass fraction of 1/1000 was added. The tetrahydrofuran preheated to 200℃ and the fructose solution containing the catalyst are injected into the static mixer (the reaction tube length is 60m) that has been preheated to 200℃ through two constant flow pumps A and B at a flow rate of 1m/s. The volume ratio of tetrahydrofuran and fructose solution is 3:1. After passing through the static mixer, the reaction liquid enters a liquid storage tank placed in an ice water bath for cooling and stratification. The upper layer is the organic phase, and the lower layer is the saturated brine phase. After liquid separation, the saturated brine layer was extracted with an equal volume of tetrahydrofuran, combined with the upper organic phase, and then distilled under reduced pressure. The yield of 5-hydroxymethyl furfural was 82%. The recovered tetrahydrofuran was directly recycled. The saturated brine The layer is recycled after adding raw materials.

Example 7

A 10% fructose solution with a mass fraction of 10% was prepared using saturated brine, and a sulfuric acid catalyst with a mass fraction of 1/1000 was added. The tetrahydrofuran preheated to 200℃ and the fructose solution containing the catalyst are injected into the static mixer (the reaction tube length is 60m) that has been preheated to 200℃ through two constant flow pumps A and B at a flow rate of 1m/s. The volume ratio of tetrahydrofuran and fructose solution is 1:1. After passing through the static mixer, the reaction liquid enters a liquid storage tank placed in an ice water bath for cooling and stratification. The upper layer is the organic phase, and the lower layer is the saturated brine phase. After liquid separation, the saturated brine layer was extracted with an equal volume of tetrahydrofuran, combined with the upper organic phase, and then distilled under reduced pressure. The yield of 5-hydroxymethyl furfural was 72%. The recovered tetrahydrofuran was directly recycled and the saturated brine The layer is recycled after adding raw materials.

Example 8

A fructose solution with a mass fraction of 10% was prepared using saturated brine, and a formic acid catalyst with a mass fraction of 1/1000 was added. The tetrahydrofuran preheated to 200℃ and the fructose solution containing the catalyst are injected into the static mixer (the reaction tube length is 60m) that has been preheated to 200℃ through two constant flow pumps A and B at a flow rate of 1m/s. The volume ratio of tetrahydrofuran and fructose solution is 20:1. After passing through the static mixer, the reaction liquid enters a liquid storage tank placed in an ice water bath for cooling and stratification. The upper layer is the organic phase, and the lower layer is the saturated brine phase. After liquid separation, the saturated brine layer was extracted with an equal volume of tetrahydrofuran, combined with the upper organic phase, and then distilled under reduced pressure. The yield of 5-hydroxymethyl furfural was 97%. The recovered tetrahydrofuran was directly recycled. The saturated brine The layer is recycled after adding raw materials.

Example 9

A 10% fructose solution with a mass fraction of 10% was prepared using saturated brine, and a sulfuric acid catalyst with a mass fraction of 1/1000 was added. The unpreheated tetrahydrofuran and the fructose solution containing the catalyst are injected into the static mixer (the reaction tube length is 60m) that has been preheated to 240°C at a flow rate of 1m/s through two constant flow pumps A and B respectively. The volume ratio of tetrahydrofuran and fructose solution is 3:1. After passing through the static mixer, the reaction liquid enters a liquid storage tank placed in an ice water bath for cooling and stratification. The upper layer is the organic phase, and the lower layer is the saturated brine phase. After liquid separation, the saturated brine layer was extracted with an equal volume of tetrahydrofuran, combined with the upper organic phase, and then distilled under reduced pressure. The yield of 5-hydroxymethyl furfural was 71%. The recovered tetrahydrofuran was directly recycled. The saturated brine The layer is recycled after adding raw materials.

Example 10

Use saturated saline to prepare a 10% fructose solution, and add a sulfuric acid catalyst with a mass fraction of one thousandth. The unpreheated tetrahydrofuran and the fructose solution containing the catalyst are injected into the static mixer (the reaction tube length is 60m) that has been preheated to 200℃ through two constant flow pumps A and B at a flow rate of 1m/s. The volume ratio of tetrahydrofuran and fructose solution is 3:1. After passing through the static mixer, the reaction liquid enters a liquid storage tank placed in an ice water bath for cooling and stratification. The upper layer is the organic phase, and the lower layer is the saturated brine phase. After liquid separation, the saturated brine layer was extracted with an equal volume of tetrahydrofuran, combined with the upper organic phase, and then distilled under reduced pressure. The yield of 5-hydroxymethyl furfural was 77%. The recovered tetrahydrofuran was directly recycled and saturated brine The layer is recycled after adding raw materials.

Example 11

A 10% fructose solution with a mass fraction of 10% was prepared using saturated brine, and a sulfuric acid catalyst with a mass fraction of 1/1000 was added. The unpreheated tetrahydrofuran and the fructose solution containing the catalyst are injected into the static mixer (the reaction tube length is 60m) that has been preheated to 160°C at a flow rate of 1m/s through two constant flow pumps A and B respectively. The volume ratio of tetrahydrofuran and fructose solution is 3:1. After passing through the static mixer, the reaction liquid enters a liquid storage tank placed in an ice water bath for cooling and stratification. The upper layer is the organic phase, and the lower layer is the saturated brine phase. After liquid separation, the saturated brine layer was extracted with an equal volume of tetrahydrofuran, combined with the upper organic phase, and then distilled under reduced pressure. The yield of 5-hydroxymethyl furfural was 64%. The recovered tetrahydrofuran was directly recycled and the saturated brine The layer is recycled after adding raw materials.

Example 12

A fructose solution with a mass fraction of 5% was prepared using saturated brine, and a sulfuric acid catalyst with a mass fraction of 1/1000 was added. The unpreheated tetrahydrofuran and the fructose solution containing the catalyst are injected into the static mixer (the reaction tube length is 60m) that has been preheated to 200℃ through two constant flow pumps A and B at a flow rate of 1m/s. The volume ratio of tetrahydrofuran and fructose solution is 3:1. After passing through the static mixer, the reaction liquid enters a liquid storage tank placed in an ice water bath for cooling and stratification. The upper layer is the organic phase, and the lower layer is the saturated brine phase. After liquid separation, the saturated brine layer was extracted with an equal volume of tetrahydrofuran, combined with the upper organic phase, and then distilled under reduced pressure. The yield of 5-hydroxymethyl furfural was 73%. The recovered tetrahydrofuran was directly recycled and the saturated brine The layer is recycled after adding raw materials.

Example 13

Saturated salt water is used to prepare a 60% fructose solution, and a sulfuric acid catalyst with a mass fraction of one thousandth is added. The unpreheated tetrahydrofuran and the fructose solution containing the catalyst are injected into the static mixer (the reaction tube length is 60m) that has been preheated to 200℃ through two constant flow pumps A and B at a flow rate of 1m/s. The volume ratio of tetrahydrofuran and fructose solution is 3:1. After passing through the static mixer, the reaction liquid enters a liquid storage tank placed in an ice water bath for cooling and stratification. The upper layer is the organic phase, and the lower layer is the saturated brine phase. After liquid separation, the saturated brine layer was extracted with an equal volume of tetrahydrofuran, combined with the upper organic phase, and then distilled under reduced pressure. The yield of 5-hydroxymethyl furfural was 76%. The recovered tetrahydrofuran was directly recycled. The saturated brine The layer is recycled after adding raw materials.

Example 14

A 10% fructose solution with a mass fraction of 10% was prepared using saturated brine, and a sulfuric acid catalyst with a mass fraction of 1/1000 was added. The unpreheated tetrahydrofuran and the fructose solution containing the catalyst are injected into the static mixer (the reaction tube length is 60m) that has been preheated to 200°C through two constant flow pumps A and B at a flow rate of 3m/s. The volume ratio of tetrahydrofuran and fructose solution is 3:1. After passing through the static mixer, the reaction liquid enters a liquid storage tank placed in an ice water bath for cooling and stratification. The upper layer is the organic phase, and the lower layer is the saturated brine phase. After liquid separation, the saturated brine layer was extracted with an equal volume of tetrahydrofuran, combined with the upper organic phase, and then distilled under reduced pressure. The yield of 5-hydroxymethyl furfural was 72%. The recovered tetrahydrofuran was directly recycled and the saturated brine The layer is recycled after adding raw materials.

Example 15

A 10% fructose solution with a mass fraction of 10% was prepared using saturated brine, and a 1-(3-sulfonylpropyl)-3-methylimidazole hydrogensulfate catalyst with a mass fraction of 2% was added. The unpreheated tetrahydrofuran and the fructose solution containing the catalyst are injected into the static mixer (the reaction tube length is 60m) that has been preheated to 200℃ through two constant flow pumps A and B at a flow rate of 1m/s. The volume ratio of tetrahydrofuran and fructose solution is 3:1. After passing through the static mixer, the reaction liquid enters a liquid storage tank placed in an ice water bath for cooling and stratification. The upper layer is the organic phase, and the lower layer is the saturated brine phase. After liquid separation, the saturated brine layer was extracted with an equal volume of tetrahydrofuran, combined with the upper organic phase, and then distilled under reduced pressure. The yield of 5-hydroxymethyl furfural was 69%. The recovered tetrahydrofuran was directly recycled. The saturated brine The layer is recycled after adding raw materials.

Example 16

A 10% mass fraction of fructose solution was prepared using saturated brine, and a 5% mass fraction of formic acid catalyst was added. The unpreheated tetrahydrofuran and the fructose solution containing the catalyst are injected into the static mixer (the reaction tube length is 60m) that has been preheated to 200℃ through two constant flow pumps A and B at a flow rate of 1m/s. The volume ratio of tetrahydrofuran and fructose solution is 3:1. After passing through the static mixer, the reaction liquid enters a liquid storage tank placed in an ice water bath for cooling and stratification. The upper layer is the organic phase, and the lower layer is the saturated brine phase. After liquid separation, the saturated brine layer was extracted with an equal volume of tetrahydrofuran, combined with the upper organic phase, and then distilled under reduced pressure. The yield of 5-hydroxymethyl furfural was 61%. The recovered tetrahydrofuran was directly recycled. The saturated brine The layer is recycled after adding raw materials.

Example 17

A 10% fructose solution with a mass fraction of 10% was prepared using saturated brine, and a sulfuric acid catalyst with a mass fraction of 1/1000 was added. The unpreheated tetrahydrofuran and the fructose solution containing the catalyst are injected into the static mixer (the reaction tube length is 60m) that has been preheated to 200℃ through two constant flow pumps A and B at a flow rate of 1m/s. The volume ratio of tetrahydrofuran and fructose solution is 1:1. After passing through the static mixer, the reaction liquid enters a liquid storage tank placed in an ice-water bath for cooling and separation. The upper layer is the organic phase, and the lower layer is the saturated brine phase. After liquid separation, the saturated brine layer was extracted with an equal volume of tetrahydrofuran, combined with the upper organic phase, and then distilled under reduced pressure. The yield of 5-hydroxymethyl furfural was 65%. The recovered tetrahydrofuran was directly recycled and the saturated brine The layer is recycled after adding raw materials.

Example 18

A 10% fructose solution with a mass fraction of 10% was prepared using saturated brine, and a sulfuric acid catalyst with a mass fraction of 1/1000 was added. The unpreheated tetrahydrofuran and the fructose solution containing the catalyst are injected into the static mixer (the reaction tube length is 60m) that has been preheated to 200℃ through two constant flow pumps A and B at a flow rate of 1m/s. The volume ratio of tetrahydrofuran and fructose solution is 20:1. After passing through the static mixer, the reaction liquid enters a liquid storage tank placed in an ice water bath for cooling and stratification. The upper layer is the organic phase, and the lower layer is the saturated brine phase. After liquid separation, the saturated brine layer was extracted with an equal volume of tetrahydrofuran, combined with the upper organic phase, and then distilled under reduced pressure. The yield of 5-hydroxymethyl furfural was 76%. The recovered tetrahydrofuran was directly recycled. The saturated brine The layer is recycled after adding raw materials.

Example 19

A 10% fructose solution with a mass fraction of 10% was prepared using saturated brine, and a sulfuric acid catalyst with a mass fraction of 1/1000 was added. The tetrahydrofuran preheated to 200°C and the fructose solution containing the catalyst are injected into the autoclave that has been preheated to 200°C through a feeding pump, and the volume ratio of the tetrahydrofuran to the fructose solution is 3:1. React at 200°C for 3 minutes, cool the reaction kettle with ice water to room temperature, and separate the layers. The upper layer is the organic phase, and the lower layer is the saturated brine phase. After the separation, the saturated brine layer is extracted with an equal volume of tetrahydrofuran and combined with the upper organic phase. After vacuum distillation, the yield of 5-hydroxymethyl furfural is 58%, the recovered tetrahydrofuran is directly recycled, and the saturated brine layer is recycled after adding raw materials.

Example 20

A 10% fructose solution with a mass fraction of 10% was prepared using saturated brine, and a sulfuric acid catalyst with a mass fraction of 1/1000 was added. The unpreheated tetrahydrofuran and the fructose solution containing the catalyst are injected into the autoclave that has been preheated to 200° C. through a feeding pump, and the volume ratio of the tetrahydrofuran to the fructose solution is 3:1. React at 200°C for 3 minutes, cool the reactor with ice water to room temperature, separate the layers, the upper layer is the organic phase, and the lower layer is the saturated saline phase. After separation, the saturated saline layer is extracted with an equal volume of tetrahydrofuran and combined with the upper organic phase. Under reduced pressure distillation, the yield of 5-hydroxymethyl furfural is 51%, the recovered tetrahydrofuran is directly recycled, and the saturated brine layer is recycled after adding raw materials.

Example 21

Add 4g of tetrahydrofuran to a 50ml autoclave and preheat to 180°C. Use a feeding pump to add the reaction solution containing 1.4g of saturated brine, 0.6g of fructose, and 0.006g of 1-(3-sulfonylpropyl)-3-methylimidazole hydrogensulfate into the preheated reaction kettle, React at 180°C for 3 min. The reaction kettle was cooled with ice water to room temperature, and the liquids were separated. The upper layer was the organic phase, and the lower layer was the saturated brine phase. The saturated brine phase was extracted three times with 2 g of tetrahydrofuran, combined with the original upper tetrahydrofuran phase, and then subjected to vacuum distillation to obtain HMF with a purity of 98% and a yield of 95%.

Example 22

Add 4g of tetrahydrofuran, 1.4g of saturated brine, 0.6g of fructose, and 0.006g of 1-(3-sulfonylpropyl)-3-methylimidazole hydrogensulfate into a 50ml autoclave, and heat to 180°C. Continue to react for 3 minutes. The reaction kettle was cooled with ice water to room temperature, and the liquids were separated. The upper layer was the organic phase and the lower layer was the saturated brine phase. The saturated brine phase was extracted three times with 2 g of tetrahydrofuran, combined with the original upper tetrahydrofuran phase, and then subjected to vacuum distillation to obtain HMF with a purity of 98% and a yield of 85%.

Example 23

Add 4g of tetrahydrofuran to a 50ml autoclave and preheat to 180°C. Use a feeding pump to add the reaction solution containing 1.9g of saturated brine, 0.1g of fructose, and 0.006g of 1-(3-sulfonylpropyl)-3-methylimidazole hydrogensulfate into the preheated reaction kettle, React at 180°C for 3 min. The reaction kettle was cooled with ice water to room temperature, and the liquids were separated. The upper layer was the organic phase and the lower layer was the saturated brine phase. The saturated brine phase was extracted three times with 2 g of tetrahydrofuran, combined with the original upper tetrahydrofuran phase, and then subjected to vacuum distillation to obtain HMF with a purity of 98% and a yield of 92%.

Example 24

Add 4g of tetrahydrofuran, 1.9g of saturated brine, 0.1g of fructose, and 0.006g of 1-(3-sulfonylpropyl)-3-methylimidazole hydrogensulfate into a 50ml autoclave, and heat to 180°C. , Reaction for 3min. The reaction kettle was cooled with ice water to room temperature, and the liquids were separated. The upper layer was the organic phase and the lower layer was the saturated brine phase. The saturated brine phase was extracted three times with 2 g of tetrahydrofuran, combined with the original upper tetrahydrofuran phase, and then subjected to vacuum distillation to obtain HMF with a purity of 98% and a yield of 81%.

Example 25

Add 4g of tetrahydrofuran to a 50ml autoclave and preheat to 180°C. Use a feeding pump to add the reaction solution containing 0.8g of saturated brine, 1.2g of fructose, and 0.006g of 1-(3-sulfopropyl)-3-methylimidazole hydrogensulfate into the preheated reaction kettle, React at 180°C for 3 min. The reaction kettle was cooled with ice water to room temperature, and the liquids were separated. The upper layer was the organic phase and the lower layer was the saturated brine phase. The saturated brine phase was extracted three times with 2 g of tetrahydrofuran, combined with the original upper tetrahydrofuran phase, and then subjected to vacuum distillation to obtain HMF with a purity of 98% and a yield of 85%.

Example 26

Add 4g of tetrahydrofuran, 0.8g of saturated brine, 1.2g of fructose, and 0.006g of 1-(3-sulfonylpropyl)-3-methylimidazole hydrogensulfate into a 50ml autoclave, and heat to 180°C. , Reaction for 3min. The reaction kettle was cooled with ice water to room temperature, and the liquids were separated. The upper layer was the organic phase and the lower layer was the saturated brine phase. The saturated brine phase was extracted three times with 2 g of tetrahydrofuran, combined with the original upper tetrahydrofuran phase, and then subjected to vacuum distillation to obtain HMF with a purity of 98% and a yield of 80%.

Example 27

Add 4g of tetrahydrofuran to a 50ml autoclave and preheat to 180°C. Use a feeding pump to add the reaction solution containing 1.4g of saturated brine, 0.6g of fructose, and 0.0002g of 1-(3-sulfopropyl)-3-methylimidazole bisulfate into the preheated reaction kettle, React at 180°C for 3 min. The reaction kettle was cooled with ice water to room temperature, and the liquids were separated. The upper layer was the organic phase and the lower layer was the saturated brine phase. The saturated brine phase was extracted three times with 2 g of tetrahydrofuran, combined with the original upper tetrahydrofuran phase, and then subjected to vacuum distillation to obtain HMF with a purity of 98% and a yield of 82%.

Example 28

Add 4g of tetrahydrofuran, 1.4g of saturated brine, 0.6g of fructose, and 0.0002g of 1-(3-sulfonylpropyl)-3-methylimidazole hydrogensulfate into a 50ml autoclave, and heat to 180°C. , Reaction for 3min. The reaction kettle was cooled with ice water to room temperature, and the liquids were separated. The upper layer was the organic phase and the lower layer was the saturated brine phase. The saturated brine phase was extracted three times with 2 g of tetrahydrofuran, combined with the original upper tetrahydrofuran phase, and then subjected to vacuum distillation to obtain HMF with a purity of 98% and a yield of 76%.

Example 29

Add 4g of tetrahydrofuran to a 50ml autoclave and preheat to 180°C. Use a feeding pump to add the reaction solution containing 1.3 g of saturated brine, 0.6 g of fructose, and 0.1 g of 1-(3-sulfopropyl)-3-methylimidazole hydrogen sulfate into the preheated reaction kettle, React at 180°C for 3 min. The reaction kettle was cooled with ice water to room temperature, and the liquids were separated. The upper layer was the organic phase and the lower layer was the saturated brine phase. The saturated brine phase was extracted three times with 2 g of tetrahydrofuran, combined with the original upper tetrahydrofuran phase, and then subjected to vacuum distillation to obtain HMF with a purity of 98% and a yield of 81%.

Example 30

Add 4g of tetrahydrofuran, 1.3g of saturated brine, 0.6g of fructose, and 0.1g of 1-(3-sulfopropyl)-3-methylimidazole bisulfate into a 50ml autoclave, and heat to 180°C. , Reaction for 3min. The reaction kettle was cooled with ice water to room temperature, and the liquids were separated. The upper layer was the organic phase and the lower layer was the saturated brine phase. The saturated brine phase was extracted three times with 2 g of tetrahydrofuran, combined with the original upper tetrahydrofuran phase, and then subjected to vacuum distillation to obtain HMF with a purity of 98% and a yield of 75%.

Example 31

Add 4g of tetrahydrofuran to a 50ml autoclave and preheat to 240°C. Use a feeding pump to add the reaction solution containing 1.4g of saturated brine, 0.6g of fructose, and 0.0002g of 1-(3-sulfopropyl)-3-methylimidazole bisulfate into the preheated reaction kettle, React at 240°C for 3 min. The reaction kettle was cooled with ice water to room temperature, and the liquids were separated. The upper layer was the organic phase and the lower layer was the saturated brine phase. The saturated brine phase was extracted three times with 2 g of tetrahydrofuran, combined with the original upper tetrahydrofuran phase, and then subjected to vacuum distillation to obtain HMF with a purity of 98% and a yield of 85%.

Example 32

Add 4g of tetrahydrofuran, 1.4g of saturated brine, 0.6g of fructose, and 0.0002g of 1-(3-sulfonylpropyl)-3-methylimidazole hydrogensulfate into a 50ml autoclave, and heat to 240°C. , Reaction for 3min. The reaction kettle was cooled with ice water to room temperature, and the liquids were separated. The upper layer was the organic phase and the lower layer was the saturated brine phase. The saturated brine phase was extracted three times with 2 g of tetrahydrofuran, combined with the original upper tetrahydrofuran phase, and then subjected to vacuum distillation to obtain HMF with a purity of 98% and a yield of 75%.

Example 33

Add 4g of tetrahydrofuran to a 50ml autoclave and preheat to 80°C. Use a feeding pump to add the reaction solution containing 1.4g of saturated brine, 0.6g of fructose, and 0.006g of 1-(3-sulfonylpropyl)-3-methylimidazole hydrogensulfate into the preheated reaction kettle, React at 80°C for 12h. The reaction kettle was cooled with ice water to room temperature, and the liquids were separated. The upper layer was the organic phase and the lower layer was the saturated brine phase. The saturated brine phase was extracted three times with 2 g of tetrahydrofuran, combined with the original upper tetrahydrofuran phase, and then subjected to vacuum distillation to obtain HMF with a purity of 98% and a yield of 77%.

Example 34

Add 4g of tetrahydrofuran, 1.4g of saturated brine, 0.6g of fructose, and 0.006g of 1-(3-sulfopropyl)-3-methylimidazole hydrogensulfate into a 50ml autoclave, and heat to 80°C. , Reaction for 12h. The reaction kettle was cooled with ice water to room temperature, and the liquids were separated. The upper layer was the organic phase and the lower layer was the saturated brine phase. The saturated brine phase was extracted three times with 2 g of tetrahydrofuran, combined with the original upper tetrahydrofuran phase, and then subjected to vacuum distillation to obtain HMF with a purity of 98% and a yield of 75%.

Example 35

Add 1g of tetrahydrofuran to a 50ml autoclave and preheat to 180°C. Use a feeding pump to add the reaction solution containing 1.4g of saturated brine, 0.6g of fructose, and 0.006g of 1-(3-sulfonylpropyl)-3-methylimidazole hydrogensulfate into the preheated reaction kettle, React at 180°C for 5 min. The reaction kettle was cooled with ice water to room temperature, and the liquids were separated. The upper layer was the organic phase and the lower layer was the saturated brine phase. The saturated brine phase was extracted three times with 2 g of tetrahydrofuran, combined with the original upper tetrahydrofuran phase, and then subjected to vacuum distillation to obtain HMF with a purity of 98% and a yield of 77%.

Example 36

Add 1g of tetrahydrofuran, 1.4g of saturated brine, 0.6g of fructose, and 0.006g of 1-(3-sulfopropyl)-3-methylimidazole hydrogensulfate into a 50ml autoclave, and heat to 180°C. , Reaction for 5min. The reaction kettle was cooled with ice water to room temperature, and the liquids were separated. The upper layer was the organic phase and the lower layer was the saturated brine phase. The saturated brine phase was extracted three times with 2 g of tetrahydrofuran, combined with the original upper tetrahydrofuran phase, and then subjected to vacuum distillation to obtain HMF with a purity of 98% and a yield of 75%.

Example 37

Add 40g of tetrahydrofuran to a 50ml autoclave and preheat to 180°C. Use a feeding pump to add the reaction solution containing 1.4g of saturated brine, 0.6g of fructose, and 0.006g of 1-(3-sulfonylpropyl)-3-methylimidazole hydrogensulfate into the preheated reaction kettle, React at 180°C for 5 min. The reaction kettle was cooled with ice water to room temperature, and the liquids were separated. The upper layer was the organic phase and the lower layer was the saturated brine phase. The saturated brine phase was extracted three times with 2 g of tetrahydrofuran, combined with the original upper tetrahydrofuran phase, and then subjected to vacuum distillation to obtain HMF with a purity of 98% and a yield of 94%.

Example 38

Add 40g of tetrahydrofuran, 1.4g of saturated brine, 0.6g of fructose, and 0.006g of 1-(3-sulfopropyl)-3-methylimidazole bisulfate into a 50ml autoclave, and heat to 180°C. , Reaction for 5min. The reaction kettle was cooled with ice water to room temperature, and the liquids were separated. The upper layer was the organic phase and the lower layer was the saturated brine phase. The saturated brine phase was extracted three times with 2 g of tetrahydrofuran, combined with the original upper tetrahydrofuran phase, and then subjected to vacuum distillation to obtain HMF with a purity of 98% and a yield of 78%.

Example 39

Add 100g of tetrahydrofuran to a 50ml autoclave and preheat to 180°C. Use a feeding pump to add the reaction solution containing 1.4g of saturated brine, 0.6g of fructose, and 0.006g of 1-(3-sulfonylpropyl)-3-methylimidazole hydrogensulfate into the preheated reaction kettle, React at 180°C for 5 min. The reaction kettle was cooled with ice water to room temperature, and the liquids were separated. The upper layer was the organic phase and the lower layer was the saturated brine phase. The saturated brine phase was extracted three times with 2 g of tetrahydrofuran, combined with the original upper tetrahydrofuran phase, and then subjected to vacuum distillation to obtain HMF with a purity of 98% and a yield of 95%.

Example 40

Add 100g of tetrahydrofuran, 1.4g of saturated brine, 0.6g of fructose, and 0.006g of 1-(3-sulfonylpropyl)-3-methylimidazole hydrogensulfate into a 50ml autoclave, and heat to 180°C. , Reaction for 5min. The reaction kettle was cooled with ice water to room temperature, and the liquids were separated. The upper layer was the organic phase, and the lower layer was the saturated brine phase. The saturated brine phase was extracted three times with 2 g of tetrahydrofuran, combined with the original upper tetrahydrofuran phase, and then subjected to vacuum distillation to obtain HMF with a purity of 98% and a yield of 88%.

Example 41

Add 4g of tetrahydrofuran to a 50ml autoclave and preheat to 180°C. Use a feeding pump to add the reaction solution containing 1.4g of saturated brine, 0.6g of fructose, and 0.006g of 1-(4-sulfonylbutyl)-3-methylimidazole hydrogensulfate into the preheated reaction kettle, React at 180°C for 3 min. The reaction kettle was cooled with ice water to room temperature, and the liquids were separated. The upper layer was the organic phase, and the lower layer was the saturated brine phase. The saturated brine phase was extracted three times with 2 g of tetrahydrofuran, combined with the original upper tetrahydrofuran phase, and then subjected to vacuum distillation to obtain HMF with a purity of 98% and a yield of 93%.

Example 42

Add 4g of tetrahydrofuran to a 50ml autoclave and preheat to 180°C. Use a feeding pump to add the reaction solution containing 1.4g of saturated brine, 0.6g of fructose, and 0.006g of 1-(3-sulfopropyl)-3-methylimidazole dihydrogen phosphate into the preheated reaction kettle , React at 180°C for 3min. The reaction kettle was cooled with ice water to room temperature, and the liquids were separated. The upper layer was the organic phase, and the lower layer was the saturated brine phase. The saturated brine phase was extracted three times with 2 g of tetrahydrofuran, combined with the original upper tetrahydrofuran phase, and then subjected to vacuum distillation to obtain HMF with a purity of 98% and a yield of 83%.

Example 43

Add 4g of tetrahydrofuran to a 50ml autoclave and preheat to 180°C. Use a feeding pump to add the reaction solution containing 1.4g of saturated brine, 0.6g of fructose, and 0.006g of 1-(3-sulfopropyl)-3-methylimidazole fluoride salt into the preheated reaction kettle. React at 180°C for 3 minutes. The reaction kettle was cooled with ice water to room temperature, and the liquids were separated. The upper layer was the organic phase, and the lower layer was the saturated brine phase. The saturated brine phase was extracted three times with 2 g of tetrahydrofuran, combined with the original upper tetrahydrofuran phase, and then subjected to vacuum distillation to obtain HMF with a purity of 98% and a yield of 79%.

Example 44

Add 4g of tetrahydrofuran to a 50ml autoclave and preheat to 180°C. Use a feeding pump to add the reaction solution containing 1.4g of saturated brine, 0.6g of fructose, and 0.006g of 1-(3-sulfopropyl)-3-methylimidazole chloride salt into the preheated reaction kettle. React at 180°C for 3 minutes. The reaction kettle was cooled with ice water to room temperature, and the liquids were separated. The upper layer was the organic phase, and the lower layer was the saturated brine phase. The saturated brine phase was extracted three times with 2 g of tetrahydrofuran, combined with the original upper tetrahydrofuran phase, and then subjected to vacuum distillation to obtain HMF with a purity of 98% and a yield of 83%.

Example 45

Add 4g of tetrahydrofuran to a 50ml autoclave and preheat to 180°C. Use a feeding pump to add the reaction solution containing 1.4g of saturated brine, 0.6g of fructose, and 0.006g of 1-(3-sulfopropyl)-3-methylimidazole bromide into the preheated reaction kettle. React at 180°C for 3 minutes. The reaction kettle was cooled with ice water to room temperature, and the liquids were separated. The upper layer was the organic phase, and the lower layer was the saturated brine phase. The saturated brine phase was extracted three times with 2 g of tetrahydrofuran, combined with the original upper tetrahydrofuran phase, and then subjected to vacuum distillation to obtain HMF with a purity of 98% and a yield of 80%.

Example 46

Add 4g of tetrahydrofuran to a 50ml autoclave and preheat to 180°C. Use a feeding pump to add the reaction solution containing 1.4g of saturated brine, 0.6g of fructose, and 0.006g of 1-(3-sulfonylpropyl)-3-methylimidazole iodide salt into the preheated reaction kettle. React at 180°C for 3 minutes. The reaction kettle was cooled with ice water to room temperature, and the liquids were separated. The upper layer was the organic phase, and the lower layer was the saturated brine phase. The saturated brine phase was extracted three times with 2 g of tetrahydrofuran, combined with the original upper tetrahydrofuran phase, and then subjected to vacuum distillation to obtain HMF with a purity of 98% and a yield of 79%.

Example 47

Add 4g of tetrahydrofuran to a 50ml autoclave and preheat to 180°C. Use a feeding pump to add the reaction solution containing 1.4g of saturated brine, 0.6g of fructose, and 0.006g of 1-(3-sulfopropyl)-3-methylimidazole trifluorosulfonate to the preheated reactor In, react at 180°C for 3 min. The reaction kettle was cooled with ice water to room temperature, and the liquids were separated. The upper layer was the organic phase, and the lower layer was the saturated brine phase. The saturated brine phase was extracted three times with 2 g of tetrahydrofuran, combined with the original upper tetrahydrofuran phase, and then subjected to vacuum distillation to obtain HMF with a purity of 98% and a yield of 88%.

Example 48

Add 4g of tetrahydrofuran to a 50ml autoclave and preheat to 180°C. Use a feeding pump to add the reaction solution containing 1.4g of saturated brine, 0.6g of fructose, and 0.006g of 1-(3-sulfopropyl)-3-methylimidazole p-toluenesulfonate to the preheated reactor In, react at 180°C for 3 min. The reaction kettle was cooled with ice water to room temperature, and the liquids were separated. The upper layer was the organic phase, and the lower layer was the saturated brine phase. The saturated brine phase was extracted three times with 2 g of tetrahydrofuran, combined with the original upper tetrahydrofuran phase, and then subjected to vacuum distillation to obtain HMF with a purity of 98% and a yield of 80%.

Example 49

Add 4g of tetrahydrofuran to a 50ml autoclave and preheat to 180°C. Use a feeding pump to react with 1.4g saturated brine, 0.6g fructose, and 0.006g 1-(3-sulfonylpropyl)-3-methylimidazole-bis(trifluoromethylsulfonyl)imide salt The liquid was added to the preheated reaction kettle and reacted at 180°C for 3 minutes. The reaction kettle was cooled with ice water to room temperature, and the liquids were separated. The upper layer was the organic phase, and the lower layer was the saturated brine phase. The saturated brine phase was extracted three times with 2 g of tetrahydrofuran, combined with the original upper tetrahydrofuran phase, and then subjected to vacuum distillation to obtain HMF with a purity of 98% and a yield of 78%.

Example 50

Add 4g of tetrahydrofuran to a 50ml autoclave and preheat to 180°C. A feed pump was used to add a reaction solution containing 1.4 g of saturated brine, 0.6 g of fructose, and 0.006 g of 3-sulfopropylpyridine hydrogen sulfate into the preheated reaction kettle, and react at 180°C for 3 minutes. The reaction kettle was cooled with ice water to room temperature, and the liquids were separated. The upper layer was the organic phase, and the lower layer was the saturated brine phase. The saturated brine phase was extracted three times with 2 g of tetrahydrofuran, combined with the original upper tetrahydrofuran phase, and then subjected to vacuum distillation to obtain HMF with a purity of 98% and a yield of 91%.

Example 51

Add 4g of tetrahydrofuran to a 50ml autoclave and preheat to 180°C. Use a feeding pump to add the reaction solution containing 1.4g of saturated brine, 0.6g of fructose, and 0.006g of N,N,N-tripropyl-(3-sulfonylpropyl)amine hydrogen sulfate to the preheated In the reactor, react at 180°C for 3 min. The reaction kettle was cooled with ice water to room temperature, and the liquids were separated. The upper layer was the organic phase, and the lower layer was the saturated brine phase. The saturated brine phase was extracted three times with 2 g of tetrahydrofuran, combined with the original upper tetrahydrofuran phase, and then subjected to vacuum distillation to obtain HMF with a purity of 98% and a yield of 85%.

Example 52

Add 4g of tetrahydrofuran to a 50ml autoclave and preheat to 180°C. Use a feeding pump to add the reaction solution containing 1.4g of saturated brine, 0.6g of fructose, and 0.006g of P,P,P-tripropyl-(3-sulfopropyl)phosphine hydrogen sulfate to the preheated In the reactor, react at 180°C for 3 min. The reaction kettle was cooled with ice water to room temperature, and the liquids were separated. The upper layer was the organic phase, and the lower layer was the saturated brine phase. The saturated brine phase was extracted three times with 2 g of tetrahydrofuran, combined with the original upper tetrahydrofuran phase, and then subjected to vacuum distillation to obtain HMF with a purity of 98% and a yield of 81%.

Example 53

Add 4g of tetrahydrofuran to a 50ml autoclave and preheat to 180°C. Use a feeding pump to add the reaction solution containing 1.4g of saturated brine, 0.6g of glucose, and 0.006g of 1-(3-sulfopropyl)-3-methylimidazole bisulfate into the preheated reaction kettle, React at 180°C for 3 min. The reaction kettle was cooled with ice water to room temperature, and the liquids were separated. The upper layer was the organic phase, and the lower layer was the saturated brine phase. The saturated brine phase was extracted three times with 2 g of tetrahydrofuran, combined with the original upper tetrahydrofuran phase, and then subjected to vacuum distillation to obtain HMF with a purity of 98% and a yield of 72%.

Example 54

Add 4g of tetrahydrofuran, 1.4g of saturated brine, 0.6g of glucose, and 0.006g of 1-(3-sulfonylpropyl)-3-methylimidazole hydrogensulfate into a 50ml autoclave, and heat to 180°C. , Reaction for 3min. The reaction kettle was cooled with ice water to room temperature, and the liquids were separated. The upper layer was the organic phase, and the lower layer was the saturated brine phase. The saturated brine phase was extracted three times with 2 g of tetrahydrofuran, combined with the original upper tetrahydrofuran phase, and then subjected to vacuum distillation to obtain HMF with a purity of 98% and a yield of 45%.

Example 55

Add 4g of tetrahydrofuran to a 50ml autoclave and preheat to 180°C. Use a feeding pump to add the reaction solution containing 1.4g of saturated brine, 0.6g of galactose, and 0.006g of 1-(3-sulfopropyl)-3-methylimidazole bisulfate to the preheated reaction kettle , React at 180°C for 3min. The reaction kettle was cooled with ice water to room temperature, and the liquids were separated. The upper layer was the organic phase, and the lower layer was the saturated brine phase. The saturated brine phase was extracted three times with 2 g of tetrahydrofuran, combined with the original upper tetrahydrofuran phase, and then subjected to vacuum distillation to obtain HMF with a purity of 98% and a yield of 53%.

Example 56

Add 4g of tetrahydrofuran, 1.4g of saturated brine, 0.6g of galactose, and 0.006g of 1-(3-sulfopropyl)-3-methylimidazole hydrogensulfate into a 50ml autoclave, and heat to 180°C After that, react for 3 min. The reaction kettle was cooled with ice water to room temperature, and the liquids were separated. The upper layer was the organic phase, and the lower layer was the saturated brine phase. The saturated brine phase was extracted three times with 2 g of tetrahydrofuran, combined with the original upper tetrahydrofuran phase, and then subjected to vacuum distillation to obtain HMF with a purity of 98% and a yield of 42%.

Example 57

Add 4g of tetrahydrofuran to a 50ml autoclave and preheat to 180°C. Use a feeding pump to add the reaction solution containing 1.4g of saturated brine, 0.6g of mannose, and 0.006g of 1-(3-sulfopropyl)-3-methylimidazole bisulfate into the preheated reaction kettle , React at 180°C for 3min. The reaction kettle was cooled with ice water to room temperature, and the liquids were separated. The upper layer was the organic phase, and the lower layer was the saturated brine phase. The saturated brine phase was extracted three times with 2 g of tetrahydrofuran, combined with the original upper tetrahydrofuran phase, and then subjected to vacuum distillation to obtain HMF with a purity of 98% and a yield of 53%.

Example 58

Add 4g of tetrahydrofuran, 1.4g of saturated brine, 0.6g of mannose, and 0.006g of 1-(3-sulfopropyl)-3-methylimidazole hydrogensulfate into a 50ml autoclave, and heat to 180°C Then continue to react for 3 min. The reaction kettle was cooled with ice water to room temperature, and the liquids were separated. The upper layer was the organic phase, and the lower layer was the saturated brine phase. The saturated brine phase was extracted three times with 2 g of tetrahydrofuran, combined with the original upper tetrahydrofuran phase, and then subjected to vacuum distillation to obtain HMF with a purity of 98% and a yield of 45%.

Example 59

Add 4g of tetrahydrofuran to a 50ml autoclave and preheat to 180°C. Use a feeding pump to add the reaction solution containing 1.4g of water, 0.6g of fructose, and 0.006g of 1-(3-sulfonylpropyl)-3-methylimidazole bisulfate into the preheated reaction kettle. React at ℃ for 3min. The reaction kettle was cooled with ice water to room temperature, diluted with water, and detected by high performance liquid chromatography. The yield of HMF was 35%.

Example 60

Add 4g of tetrahydrofuran, 1.4g of water, 0.6g of fructose, 0.006g of 1-(3-sulfonylpropyl)-3-methylimidazole hydrogensulfate into a 50ml autoclave, and heat to 180°C for reaction 3min. The reaction kettle was cooled with ice water to room temperature, diluted with water, and tested by high performance liquid chromatography. The yield of HMF was 12%.

Claims

A method for improving the synthesis efficiency of 5-hydroxymethyl furfural is characterized in that the raw material is six carbon sugars, and the reaction system of the method includes an organic solvent, and the organic solvent is preheated to the reaction temperature before the reaction.
The synthesis method according to claim 1, wherein the reaction system further comprises a saturated inorganic salt solution; the six-carbon sugar is fructose, glucose, mannose or galactose.
The method according to claim 2, wherein the organic solvent is tetrahydrofuran, n-butanol, 2-butanol, butanone, methyl isobutyl ketone, 2-methyltetrahydrofuran; the inorganic salt is Potassium chloride, sodium chloride, sodium sulfate, potassium sulfate, potassium bromide, sodium bromide, potassium iodide, sodium iodide, lithium chloride.
The synthesis method according to claim 3, wherein the reactor of the method is a static mixer or a high-pressure reactor; the flow rate of the solution in the static mixer is 0.1-5 m/s; the static mixer The length of the reaction tube is 10-200m.
The synthesis method according to claim 4, wherein the catalyst of the method is an organic acid, an inorganic acid, an acidic ionic liquid or a Lewis acid.
The method of claim 5, wherein:

When the reactor is a static mixer, the method includes the following steps:

(1) Mixing a saturated inorganic salt solution with raw materials to obtain a raw material solution, adding a catalyst to the raw material solution to obtain a reaction solution; the mass fraction of the raw material in the raw material solution is 5-60 wt%; in the reaction solution, the catalyst The mass fraction of 0.1%-5%;

(2) The organic solvent preheated to the reaction temperature and the reaction solution are respectively injected into the static mixer through a conveying device, and the reaction is controlled at 160-240°C;

(3) Cool the reaction liquid effluent of the static mixer in step (2), stand still for layering, and separate the liquids, and then distill the upper organic layer under reduced pressure to obtain the 5-hydroxymethyl furfural; the upper layer is organic Phase, the lower layer is saturated inorganic brine phase;

When the reactor is an autoclave, the method includes the following steps:

(1) Dissolve the raw materials and the catalyst in a saturated aqueous solution of inorganic salt to obtain a reactant solution, and place the organic solvent in an autoclave to preheat to the reaction temperature;

(2) Add the reactant solution to the reactor and treat it at 80-240°C for 1 min-12h; the mass concentration of the raw material in the reactant solution is 5%-60%, and the amount of catalyst used is 0.01% to 5% of the mass of the reactant solution, and the mass ratio of the organic solvent to the reactant solution is 0.5-50:1;

(3) Cool down, stand still for layering and liquid separation, and then distill the upper organic layer under reduced pressure to obtain the 5-hydroxymethyl furfural.
The method of claim 5, wherein:

The inorganic acid is sulfuric acid, hydrochloric acid, phosphoric acid, nitric acid,

The organic acid is formic acid, acetic acid, and propionic acid;

The Lewis acid is aluminum chloride, iron chloride, aluminum sulfate, aluminum nitrate, iron nitrate, chromium nitrate, chromium chloride;

The acidic ionic liquid is 1-(3-sulfopropyl)-3-methylimidazole hydrogensulfate, 1-(3-sulfopropyl)-3-methylimidazole chloride, 1-( 3-sulfopropyl)-3-methylimidazole bromide, 1-(3-sulfopropyl)-3-methylimidazole acetate, 1-(3-sulfopropyl)- 3-Methylimidazole hexafluorophosphate, 1-(3-sulfopropyl)-3-methylimidazole tetrafluoroborate, 1-(3-sulfopropyl)-3-methylimidazole Nitrate, 1-(3-sulfopropyl)-3-methylimidazole dihydrogen phosphate, 1-(4-sulfobutyl)-3-methylimidazole hydrogensulfate, 1-(4 -Sulfobutyl)-3-methylimidazole chloride, 1-(4-sulfobutyl)-3-methylimidazole bromide, 1-(4-sulfobutyl)-3- Methyl imidazole acetate, 1-(4-sulfobutyl)-3-methylimidazole hexafluorophosphate, 1-(4-sulfobutyl)-3-methylimidazole tetrafluoroborate Salt, 1-(4-sulfobutyl)-3-methylimidazole nitrate, 1-(4-sulfobutyl)-3-methylimidazole dihydrogen phosphate.
The method of claim 6, wherein:

When the reactor is a static mixer, the volume ratio of the organic solvent and the reactant solution described in step (2) is 1:1-20:1; the saturated inorganic brine phase in step (3) uses an equal volume of organic solvent After extraction, the extracted organic phase layer and the organic phase layer described in step (3) are combined with vacuum distillation to obtain the 5-hydroxymethyl furfural and the organic solvent is recovered; the extracted saturated inorganic brine layer is recycled after adding raw materials use;

When the reactor is an autoclave, the lower layer in step (3) is a saturated inorganic salt water layer, and the saturated inorganic salt water layer is extracted three times with an organic phase extractant of the same quality, which is the same as the upper organic phase in step (3). After merging and distillation under reduced pressure, the 5-hydroxymethyl furfural is obtained.
The method according to claim 8, wherein the organic phase extractant is tetrahydrofuran, methyl isobutyl ketone, methyl ethyl ketone, n-butanol, isobutanol or 2-methyltetrahydrofuran.
A method for improving the synthesis efficiency of 5-hydroxymethyl furfural, characterized in that the raw material of the method is fructose, the reaction system is a saturated inorganic salt solution-organic solvent system, the reactor is a static mixer, and the static mixer The flow rate of the medium solution is 0.1-5m/s; the catalyst is organic acid, inorganic acid, acidic ionic liquid or Lewis acid.
The method according to claim 10, wherein the organic solvent is tetrahydrofuran, n-butanol, 2-butanol, butanone, methyl isobutyl ketone, 2-methyltetrahydrofuran.
The method according to claim 10, wherein the inorganic salt is potassium chloride, sodium chloride, sodium sulfate, potassium sulfate, potassium bromide, sodium bromide, potassium iodide, sodium iodide, and lithium chloride.
The method according to claim 10, wherein the length of the reaction tube of the static mixer is 10-200m.
The method according to claim 10, wherein the method comprises the following steps:

(1) Mixing a saturated inorganic salt solution with fructose to obtain a fructose solution, adding a catalyst to the fructose solution to obtain a reaction solution; in the fructose solution, the mass fraction of fructose is 5-60 wt%;

(2) The organic solvent preheated to the reaction temperature and the reaction solution are respectively injected into the static mixer through a conveying device, and the reaction is controlled at 160-240°C;

(3) Cool the reaction liquid effluent of the static mixer in step (2), stand still for layering, and separate the liquids, and then distill the upper organic layer under reduced pressure to obtain the 5-hydroxymethyl furfural; the upper layer is organic The lower layer is the saturated inorganic brine phase.
The method according to claim 10, wherein the mass fraction of the catalyst in the reaction solution is 0.1% to 5%.
The method of claim 10, wherein:

The inorganic acid is sulfuric acid, hydrochloric acid, phosphoric acid, and nitric acid;

The organic acid is formic acid, acetic acid, and propionic acid;

The Lewis acid is aluminum chloride, iron chloride, aluminum sulfate, aluminum nitrate, iron nitrate, chromium nitrate, chromium chloride;

The acidic ionic liquid is 1-(3-sulfopropyl)-3-methylimidazole hydrogensulfate, 1-(3-sulfopropyl)-3-methylimidazole chloride, 1-( 3-sulfopropyl)-3-methylimidazole bromide, 1-(3-sulfopropyl)-3-methylimidazole acetate, 1-(3-sulfopropyl)- 3-Methylimidazole hexafluorophosphate, 1-(3-sulfopropyl)-3-methylimidazole tetrafluoroborate, 1-(3-sulfopropyl)-3-methylimidazole Nitrate, 1-(3-sulfopropyl)-3-methylimidazole dihydrogen phosphate, 1-(4-sulfobutyl)-3-methylimidazole hydrogensulfate, 1-(4 -Sulfobutyl)-3-methylimidazole chloride, 1-(4-sulfobutyl)-3-methylimidazole bromide, 1-(4-sulfobutyl)-3- Methyl imidazole acetate, 1-(4-sulfobutyl)-3-methylimidazole hexafluorophosphate, 1-(4-sulfobutyl)-3-methylimidazole tetrafluoroborate Salt, 1-(4-sulfobutyl)-3-methylimidazole nitrate, 1-(4-sulfobutyl)-3-methylimidazole dihydrogen phosphate.
The method according to claim 14, wherein the saturated inorganic brine phase in step (3) is extracted with an equal volume of organic solvent, and the extracted organic phase layer is combined with the organic phase layer in step (3). Pressure distillation is performed to obtain the 5-hydroxymethyl furfural and the organic solvent is recovered; the extracted saturated inorganic brine layer is supplemented with fructose and then recycled.
The method according to claim 10, wherein the flow rate of the solution in the static mixer is 1-3 m/s.
The method according to claim 14, wherein the volume ratio of the organic solvent and the reactant solution in step (2) is 1:1-20:1.