CN109942518B - A metal-free method for the one-pot preparation of 5-methylfurfural from biomass resources - Google Patents

Abstract

The invention relates to the technical field of catalysis, in particular to a method for preparing 5-methylfurfural from biomass resources in one pot without metal participation, which comprises the following steps: sequentially adding biomass or derivatives thereof, iodide, solvent and acid into a high-temperature high-pressure reaction kettle, introducing certain hydrogen, reacting for a certain time, and collecting an organic phase for fractionation after the reaction is finished to obtain the 5-methylfurfural with the yield of up to 51.9%. The method has low requirements on production equipment under the low-temperature and low-pressure conditions, and accords with the principle of safe production; the biomass or the derivative thereof is converted into the 5-methylfurfural without metal participation in selective hydrogenolysis, the raw materials are low in renewable cost, good in circularity, simple in process, mild in condition and easy to separate products, the material loss caused by the intermediate steps is avoided, and the maximum utilization of resources is realized.

Description

A metal-free method for the one-pot preparation of 5-methylfurfural from biomass resources

technical field

The invention belongs to the technical field of catalysis, and relates to a metal-free method for preparing 5-methylfurfural from biomass resources in one pot.

Background technique

Biomass is currently the only sustainable source of organic carbon on Earth and is an ideal petroleum substitute for the production of fuels, chemicals and materials. However, the complex structure and chemistry of most bio-based raw materials restrict their large-scale application. Biomass cellulose and starch are both macromolecular polysaccharides composed of glucose, which are widely distributed in nature and account for more than 50% of the carbon content in the plant kingdom. Starch is abundant in nature and exists in staple foods such as potatoes, wheat, corn, rice, and cassava, and is the most common bio-based raw material in the human diet. Glucose and fructose are the most common hexoses in nature, and their downstream derivatives, 5-hydroxymethylfurfural, are considered to be the most potential bio-based platform molecular compounds. 5-Methylfurfural (5-MF) is the deoxygenated hydrogenation product of 5-Hydroxymethylfurfural (HMF). It is also an important fine chemical widely used in medicine, pesticides, cosmetics and other industries, and it is also a general edible spice. An important component, it is even considered an important anticancer drug. In addition, it can serve as an important intermediate for renewable fuels.

The synthetic method of 5-methylfurfural in industry at present: Japanese patent JPS5791982A has reported that a kind of phosgene reacts with the mixture of 2-methylfuran and N,N-dimethylformamide earlier, then the gained reaction product is hydrolyzed to obtain 5 - Methylfurfural method. The method is widely used in industry to produce 5-methylfurfural. But there are many disadvantages in this method: 1. The raw material comes from petrochemical industry and is non-renewable. 2. Raw materials are expensive. 3. Phosgene is harmful to human body.

The method for preparing 5-methylfurfural from biomass reported in the literature mainly contains the following: 1.Mascal etc. utilize microcrystalline cellulose to be converted into 5-chloromethylfurfural under lithium chloride and concentrated hydrochloric acid conditions, and then in In a hydrogen atmosphere, catalyzed hydrogenolysis with palladium chloride was performed to obtain 5-methylfurfural (Angew. Chem. 2008, 120, 8042–8044). 2. Yang et al. used RhCl ₃ and HI to catalyze the conversion of glucose and fructose into 5-methylfurfural with a yield of 68% under a hydrogen atmosphere (ChemSusChem2011, 4, 349-352). 3. Chinese patent CN102766119A discloses that a fructo-based biomass is pyrolyzed under the catalysis of an acid catalyst to obtain bio-oil containing 20% molar yield of 5-methylfurfural.

The synthesis methods from biomass derivatives include: 5-hydroxymethylfurfural is the dehydration product of hexose. In recent years, people have continuously studied the method of preparing 5-methylfurfural from 5-hydroxymethylfurfural. In 2014, Huang et al. used HMF as a raw material and W ₂ C/AC as a catalyst to react in hydrogen and THF at 200°C for 3 hours to obtain 5-MF with a yield of 87.1%. In 2017, Li et al. used heterogeneous iron as a catalyst to catalyze HMF in a single-phase system of hydrogen and THF to obtain 5-MF with a yield of 22.1% (ChemSusChem2017, 10, 1436–1447). In the same year, Chinese patent CN107353268A reported a kind of Pd-PVP/ZrO ₂ as catalyzer, taking formic acid as hydrogen source in tetrahydrofuran (THF) to catalyze the method that 5-hydroxymethylfurfural is converted into 5-methylfurfural and obtain 86% molar yield. However, the above-mentioned methods all have problems such as expensive catalysts, complex processes, harsh conditions, and poor recyclability. For this reason, we are badly in need of a kind of catalyst that is cheap, and reaction condition is mild, the method for preparing 5-methylfurfural rapidly with simple technique.

Contents of the invention

The purpose of the invention is to solve the shortcomings of expensive catalysts and complex processes in the existing technology for preparing 5-methylfurfural. The invention provides a metal-free method for preparing 5-methylfurfural from biomass.

The present invention is realized through the following technical solutions, and the steps are as follows:

The biomass or its derivatives, iodide, solvent, and acid are added to the high-temperature and high-pressure reactor in sequence, and a certain amount of hydrogen is introduced. After reacting for a certain period of time, the organic phase is collected and fractionated to obtain 5-methylfurfural. The reaction formula is as follows:

Further, the biomass or its derivatives: iodide molar ratio is 0.01-100; the biomass or its derivatives: solvent mass ratio is 0.001-100; solvent: acid volume ratio is 10-1000; the reaction temperature is 50 ~300°C, preferably 120~200°C; hydrogen pressure is 10~1000psi, preferably 100~500psi; reaction time is 0.1~24h, preferably 1~12h.

Further, the biomass and its derivatives include: lignocellulosic biomass, cellulose, starch, inulin, sucrose, maltose, glucose, fructose and 5-hydroxymethylfurfural (HMF), or a mixture thereof.

Further, the acid is hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, hydroiodic acid, hydrobromic acid, perchloric acid, acetic acid, 3-fluorobenzenesulfonic acid, formic acid and supported on activated carbon, zirconium dioxide, titanium dioxide, A solid acid catalyst supported on silicon, aluminum oxide or molecular sieve, or a mixture thereof.

Further, the iodide includes: sodium iodide, potassium iodide, lithium iodide, hydrogen iodide, rhodium iodide, palladium iodide, ruthenium iodide and platinum iodide, or a mixture thereof.

Further, the solvent includes water, benzene, toluene, chlorobenzene, furan, tetrahydrofuran, 2-methyltetrahydrofuran, 2,5-dimethyltetrahydrofuran, methyl isobutyl ketone, 1,4-epoxyhexane , cyclohexane and n-hexane, or mixtures thereof.

Compared with prior art, the beneficial effect of the present invention is:

(1) One-pot production of 5-methylfurfural from biomass or its derivatives, which simplifies the operation process, avoids material loss caused by intermediate steps, and maximizes the utilization of resources. (2) The present invention only needs to be carried out under low temperature and low pressure conditions, and the requirements for production equipment are not high, which meets the principle of safe production. (3) The present invention uses common biomass as a raw material, has no metal catalyst, can be recycled, and the product is easy to separate to facilitate industrial application.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

Example 1

Add 100mg of starch, 2mmol of sodium iodide, 2ml of water, 0.18mmol of HCl (37wt%), 5ml of 2-methyltetrahydrofuran in a 50mL high-temperature and high-pressure reactor, seal the reactor, fill it with hydrogen (300psi), stir and rapidly heat to 160 ℃, keep 2h. Reactor ice-water bath is cooled to room temperature, collects organic phase and detects that the productive rate of 2-methylfuran in its product is 4.9%, the productive rate of furfural is 1.9%, the productive rate of 5-methylfurfural is 37.7%, total The yield was 44.5%.

The detection and calculation of 5-methylfurfural productive rate are carried out according to the following method:

Quantitative analysis adopts gas chromatograph Agilent 7820A series (FID detector, AgilentHP-5 chromatographic column: 30m*32um*0.25um). Qualitative analysis was carried out using a gas phase mass spectrometer ThermoscientificTRACE1310 (HP-5 capillary column 30m*320μm*0.25μm).

5-Methylfurfural yield calculation formula;

5-methylfurfural yield=(the molar amount of 5-methylfurfural in the organic phase/the molar amount of glucose in the biomass)×100%

Example 2

Add 100mg of starch, 4mmol of sodium iodide, 2ml of water, 0.18mmol of H ₂ SO ₄ , and 3ml of furan into a 50mL high-temperature and high-pressure reactor, stir and rapidly heat to 160°C for 2 hours. Reactor ice water bath is cooled to room temperature, collects organic phase and detects that the productive rate of 2-methylfuran in its product is 4.8%, the productive rate of furfural is 2.1%, the productive rate of 5-methylfurfural is 34.3%, total The yield was 41.2%.

Example 3

Add 100mg of starch, 2mmol of sodium iodide, 2ml of water, 0.18mmol of CF ₃ SO ₃ H, 3ml of 2-methyltetrahydrofuran into a 50mL high-temperature and high-pressure reactor, seal the reactor, fill it with hydrogen (300psi), stir and rapidly heat to 160 ℃, keep 2h. Reactor ice-water bath is cooled to room temperature, collects organic phase and detects through gas chromatography, and the productive rate of 2-methylfuran in its product is 1.9%, the productive rate of furfural is 1.6%, and the productive rate of 5-methylfurfural is 29.0%. %, the total yield is 31.5%.

Example 4

Add 100mg of glucose, 2mmol of sodium iodide, 2ml of water, 0.18mmol of HI (57wt%), and 3ml of cyclohexane in sequence in a 50mL high-temperature and high-pressure reactor, seal the reactor, fill it with hydrogen (200psi), stir and rapidly heat to 160°C , keep 2h. The reactor was cooled to room temperature in an ice-water bath, and the organic phase was collected to detect that the yield of 2-methylfuran in the product was 2.4%, the yield of 5-methylfurfural was 32.5%, and the total yield was 34.9%.

Example 5

Add 100mg fructose, 2mmol sodium iodide, 2ml water, 0.18mmol HCl (37wt%), and 3ml methyl isobutyl ketone successively in a 50mL high-temperature and high-pressure reactor, seal the reactor, fill it with hydrogen (200psi) and stir and rapidly heat to 160 ℃, keep 2h. The reactor was cooled to room temperature in an ice-water bath, and the organic phase was collected and detected. The yield of 2-methylfuran in the product was 3.1%, the yield of 5-methylfurfural was 31.2%, and the total yield was 34.3%.

Example 6

Add 0.5mmol HMF, 0.18ml HCl (37wt%), 2mmolNaI, 3ml 2-methyltetrahydrofuran to a 50mL high-temperature and high-pressure reactor in sequence, seal the reactor, fill it with hydrogen (300psi), stir and rapidly heat to 160°C and keep for 2h. Cool the reactor to room temperature in an ice-water bath, collect the organic phase and detect that the yield of 5-methylfurfural in the product is 51.9%, the yield of 2,5-diformylfuran is 35.6%, and the total yield is 87.5%. .

Example 7

Add 100mg of starch, 2mmol of sodium iodide, 2ml of water, 0.18mmol of HCl (37wt%), and 3ml of n-octane in sequence into a 50mL high-temperature and high-pressure reactor, seal the reactor, fill it with hydrogen (100psi), stir and rapidly heat to 180°C , keep 1h. Reactor ice-water bath is cooled to room temperature, collects organic phase and detects, and the productive rate of 2-methylfuran in its product is 4.2%, and the productive rate of furfural is 1.6%, and the productive rate of 5-methylfurfural is 10.1%, The overall yield is 15.9%.

Example 8

Add 100mg of starch, 2mmol of potassium iodide, 2ml of water, 0.18mmol of HCl (37wt%), and 3ml of toluene into a 50mL high-temperature and high-pressure reactor in sequence, seal the reactor, fill it with hydrogen (500psi), stir and rapidly heat to 160°C and keep for 2h. Reactor ice-water bath is cooled to room temperature, collects organic phase and detects, and the productive rate of 2-methylfuran in its product is 2.5%, and the productive rate of furfural is 2.3%, and the productive rate of 5-methylfurfural is 36.5%, The overall yield was 41.3%.

Example 9

Add 100 mg of inulin, 4 mmol of lithium iodide, 2 ml of water, 0.18 mmol of HCl (37 wt%), and 3 ml of toluene in sequence in a 50 mL high-temperature and high-pressure reactor, seal the reactor, fill it with hydrogen (500 psi), stir and rapidly heat to 160 ° C, Keep for 2h. Reactor ice-water bath is cooled to room temperature, collects organic phase and detects, and the productive rate of 2-methylfuran in its product is 1.7%, and the productive rate of furfural is 1.3%, and the productive rate of 5-methylfurfural is 38.5%, The overall yield is 41.5%.

Example 10

Add 1.0mmol maltose, 2mmol hydrogen iodide, 1ml water, 3ml 2,5-dimethyltetrahydrofuran to a 50mL high-temperature and high-pressure reactor in sequence, seal the reactor, fill it with hydrogen (500psi), stir and rapidly heat to 150°C, Keep for 2h. The reactor was cooled to room temperature in an ice-water bath, and the organic phase was collected and detected. The yield of 2-methylfuran in the product was 3.7%, the yield of 5-methylfurfural was 42.5%, and the total yield was 46.2%.

Claims (1)

1. A method for preparing 5-methylfurfural from biomass resources in one pot without metal participation is characterized by comprising the following steps: sequentially adding biomass or derivatives thereof, iodide, solvent and acid into a high-temperature high-pressure reaction kettle, introducing certain hydrogen, reacting for a certain time, and collecting an organic phase for fractionation after the reaction is finished to obtain 5-methylfurfural, wherein the biomass or derivatives thereof are prepared by the steps of: iodide mass molar ratio is 25mg to 1mmol or 50mg to 1mmol; biomass or derivatives thereof: the mass volume ratio of the solvent is 100mg to 5mL or 100mg to 7mL; acid: the molar volume ratio of the solvent is 0.18mmol to 5mL or 0.18mmol to 7mL; the reaction temperature is 160-200 ℃, the hydrogen pressure is 200-500 psi, and the reaction time is 2-12 h; the biomass and its derivatives include: lignocellulosic biomass, cellulose, starch, inulin, sucrose, maltose, glucose, fructose and 5-hydroxymethylfurfural or mixtures thereof; the acid is hydrochloric acid or sulfuric acid; the iodide is one or more of sodium iodide, potassium iodide, lithium iodide, hydrogen iodide, rhodium iodide, palladium iodide, ruthenium iodide and platinum iodide; the solvent is one or more of water, benzene, toluene, chlorobenzene, furan, tetrahydrofuran, 2-methyltetrahydrofuran, 2, 5-dimethyltetrahydrofuran, methyl isobutyl ketone, 1, 4-epoxyhexa-ne, cyclohexane and n-hexane.