Method for preparing 5-hydroxymethylfurfural from waste cigarette butts and filter tips

Abstract

The invention discloses a method for preparing 5-hydroxymethylfurfural by using a waste cigarette end filter tip, which comprises the following steps: uniformly mixing a cigarette end filter tip, an organic solvent and water, adding a metal salt catalyst, heating to a reaction temperature, and reacting to generate 5-hydroxymethylfurfural; the organic solvent is acetone; the volume ratio of the organic solvent to the water is 9: 1-1: 9; the ratio of the total amount of the water and the organic solvent to the volume mass of the cigarette end filter tip is (100: 1)-(10: 1 mL / g); the metal salt catalyst is at least one of aluminum chloride, chromium chloride and ferric chloride. According to the method, a one-step method is adopted, the waste cigarette end filter tips are directly and efficiently converted into the 5-hydroxymethylfurfural under the relatively mild condition, the yield of the 5-hydroxymethylfurfural is high and can exceed 50% at most, and high-value utilization of the waste cigarette ends is achieved. The organic solvent used in the reaction process is easy to recover and can be recycled, and industrial amplification and application of the technology are facilitated.

Description

Technical Field

[0001] The present invention belongs to the field of waste resource utilization, and specifically relates to a method for preparing 5-hydroxymethylfurfural by using waste cigarette butt filters (cellulose acetate). Technical Background

[0002] Cellulose acetate is a derivative of cellulose, usually synthesized by esterification reaction of cellulose and acetic anhydride under the catalysis of acid. Due to its good adsorption, elasticity and thermal stability, cellulose acetate is widely used in the preparation of cigarette filters to effectively adsorb and filter harmful substances such as tar and nicotine in cigarette smoke, reducing the content of harmful substances entering the human body. Cigarette butts are a common type of waste. The cellulose acetate component in cigarette butt filters has certain acid and alkali resistance and is difficult to degrade under natural conditions, having an adverse impact on the environment. Currently, these waste materials are mainly treated by incineration and landfill, which not only damage the environment but also cause waste of resources.

[0003] 5-Hydroxymethylfurfural (HMF) is a multifunctional platform chemical and is considered an important precursor for the production of high-value biofuels, polymers and chemicals. HMF can be further converted into a variety of high-value-added chemicals through various chemical reactions such as oxidation, reduction, etherification, esterification, amination, acetalization, decarbonylation and halogenation, such as 2,5-furandicarboxylic acid, 2,5-dimethylfuran, 2,5-furandimethanol, levulinic acid, adipic acid, etc. These chemicals have wide applications in the fields of polymers, biofuels, solvents, pharmaceuticals, etc. Cellulose is the most widely distributed natural renewable polymer in nature. In recent years, the preparation of 5-hydroxymethylfurfural from cellulose and other biomass raw materials has received extensive attention. Cellulose derivatives such as formylated cellulose can also be efficiently converted into 5-hydroxymethylfurfural through hydrolysis, isomerization, dehydration and other steps.

[0004] As a derivative of cellulose modified by acetylation, cellulose acetate has great potential in the synthesis of 5-hydroxymethylfurfural. Therefore, synthesizing 5-hydroxymethylfurfural from waste cigarette butt filters can not only solve the problem of environmental pollution caused by waste cigarette butts, but also realize their resource recycling. Currently, there is no related technology for synthesizing 5-hydroxymethylfurfural from waste cigarette butt filters. Summary of the Invention

[0005] The present invention aims at the resource recycling of waste cigarette butts and provides a method for preparing 5-hydroxymethylfurfural by using waste cigarette butt filters (cellulose acetate).

[0006] The object of the present invention is achieved by the following technical solutions:

[0007] A method for preparing 5-hydroxymethylfurfural by using waste cigarette butt filters, comprising:

[0008] Mix the cigarette butt filter, organic solvent and water evenly, add a metal salt catalyst, heat to the reaction temperature, and react to produce 5-hydroxymethylfurfural.

[0009] The organic solvent is acetone; the volume ratio of the organic solvent to water is 9:1 to 1:9, preferably 7:3 to 4:1, more preferably 4:1; the total volume of water and organic solvent and the volume-mass ratio of the cigarette butt filter is 100:1 to 10:1 mL / g, preferably 100:2 to 100:5 mL / g, more preferably 100:5 mL / g.

[0010] The metal salt catalyst is at least one of aluminum chloride, chromium chloride, and iron chloride, preferably aluminum chloride.

[0011] The dosage ratio of the cigarette butt filter to the metal salt catalyst is 1:0.3125 to 1:2.5 g / mmol, preferably 1:0.625 to 1:1.25 g / mmol.

[0012] Heating is carried out by traditional heat conduction, the reaction temperature is 130 to 180 °C, preferably 160 °C; the reaction time is 10 to 300 min, preferably 30 to 60 min.

[0013] As a further preferred embodiment of the method for preparing 5-hydroxymethylfurfural using waste cigarette butt filters according to the present invention, it further includes: after the reaction, the reaction solution is rotary evaporated under reduced pressure to recover the organic solvent, activated carbon is added to the residual liquid, mixed evenly, and filtered; an extractant is added to the filtrate for extraction, and the extraction phase (oil phase) and the raffinate phase (water phase) are separated. The extraction phase contains 5-hydroxymethylfurfural. The same volume of extractant is added to the raffinate phase again, and the extraction phase (oil phase) is separated. The extraction phases obtained twice are combined; the extraction phase is purified by vacuum distillation or rectification to obtain 5-hydroxymethylfurfural.

[0014] The conditions for vacuum distillation of the reaction solution are a temperature of 40 °C and a pressure of 100 mbar. The recovered organic solvent is recycled.

[0015] The mass-volume ratio of the activated carbon to the residual liquid is 1:15 g / mL.

[0016] The extractant is at least one of methyl isobutyl ketone (MIBK) and ethyl acetate.

[0017] The volume ratio of the extractant to the filtrate is 1:1.

[0018] The conditions for vacuum distillation of the extraction phase are a temperature of 40 °C and a pressure of 50 mbar.

[0019] The beneficial effects of the present invention:

[0020] The present invention adopts a one-step method to directly and efficiently convert waste cigarette butt filters into 5-hydroxymethylfurfural under relatively mild conditions. The yield of 5-hydroxymethylfurfural is relatively high, with a maximum exceeding 50%, realizing the high-value utilization of waste cigarette butts.

[0021] The organic solvent used in the reaction process of the present invention is easy to recover and can be recycled, which is conducive to the industrial scale-up and application of the technology.

[0022] The types of metal catalysts used in the present invention are single, which is easy for subsequent wastewater treatment. Description of the Drawings

[0023] Figure 1 is the reaction flow chart of the method for preparing 5-hydroxymethylfurfural from waste cigarette butt filters in the present invention. Detailed Embodiments

[0024] The following will explain the solution of the present invention in combination with embodiments. Those skilled in the art will understand that the following embodiments are only a part of the embodiments of the present invention, rather than all the embodiments, and should not be regarded as limiting the scope of the present invention. For those not specified in the embodiments regarding specific technologies or conditions, they shall be carried out according to the technologies or conditions described in the literature in this field or according to the product specifications. Those materials, reagents and instruments without indicating the manufacturer can be obtained as conventional products through commercial purchase.

[0025] Many specific details are set forth in the following description in order to fully understand the present invention, but the present invention can also be implemented in other ways different from those described herein. It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0026] Example 1

[0027] Take 0.3 g of dried cigarette butt filter (corresponding to a substrate concentration of 2%, mass g / total volume of reaction system solution mL × 100), 12 mL of acetone, and 3 mL of water and place them in a 25 mL reaction kettle. React with aluminum chloride, chromium chloride, and iron chloride as metal catalysts respectively. The catalyst dosage is 0.375 mmol. Under the condition of a magnetic stirring speed of 700 rpm, heat the reaction kettle to 160 °C by means of heat conduction heating, keep it for 40 min, cool it to room temperature, measure the HMF concentration in the reaction system by HPLC, and combine 1 the degree of acetyl substitution of cellulose acetate, the component of the unused cigarette butt filter determined by HNMR, determine the molar mass of cellulose acetate, and calculate the HMF yield. The specific experimental parameters and HMF yield are shown in Table 1.

[0028] It can be seen that aluminum chloride, chromium chloride, and iron chloride can all catalyze the preparation of 5-hydroxymethylfurfural from cigarette butt filters; under the same dosage, the catalytic effects of aluminum chloride and chromium chloride are relatively good.

[0029] Table 1. Influence of Different Kinds of Metal Catalysts on the Yield of HMF

[0030]

[0031] Example 2

[0032] Take 0.3 g of dried cigarette butt filter tips, 12 mL of acetone, and 3 mL of water and place them in a 25 mL reaction kettle. Add 0.375 mmol of aluminum chloride. Under the condition of a magnetic stirring speed of 700 rpm, use the method of heat conduction heating to heat the reaction kettle to 150 °C, 160 °C, and 170 °C respectively, and keep them for 40 min. Cool to room temperature, use HPLC to measure the concentration of HMF in the reaction system, and combine with 1 the degree of acetyl substitution of cellulose acetate, the component of the unused cigarette butt filter tip measured by HNMR, determine the molar mass of cellulose acetate, calculate the HMF yield. The specific experimental parameters and HMF yield are shown in Table 2.

[0033] Table 2. Influence of Reaction Temperature on the Yield of HMF

[0034]

[0035] Example 3

[0036] Take 0.3 g of dried cigarette butt filter tips, acetone and water (the total volume of the reaction system solvent is 15 mL, and the volume ratios of acetone and water are 1:1, 7:3, 4:1, and 9:1 respectively) and place them in a 25 mL reaction kettle. Add aluminum chloride so that the amount is 0.375 mmol. Under the condition of a magnetic stirring speed of 700 rpm, use the method of heat conduction heating to heat the reaction kettle to 160 °C, keep it for 40 min, cool to room temperature, use HPLC to measure the concentration of HMF in the reaction system, and combine with 1 the degree of acetyl substitution of cellulose acetate, the component of the unused cigarette butt filter tip measured by H NMR, determine the molar mass of cellulose acetate, calculate the HMF yield. The specific experimental parameters and HMF yield are shown in Table 3.

[0037] It can be seen that reaction systems composed of acetone and water with different volume ratios can all catalyze the preparation of 5-hydroxymethylfurfural from cigarette butt filter tips; and when the volume ratio of acetone to water is 4:1, the yield of 5-hydroxymethylfurfural is the highest.

[0038] Table 3. Influence of the Volume Ratio of Organic Solvent and Water on the Yield of HMF

[0039]

[0040] Example 4

[0041] Take 0.3 g of dried cigarette butt filter tips, 12 mL of acetone, and 3 mL of water and place them in a 25 mL reaction kettle. Add 0.09375 mmol, 0.1875 mmol, 0.375 mmol, and 0.75 mmol of aluminum chloride respectively. Under magnetic stirring, heat the reaction kettle to 160 °C by means of heat conduction heating, hold for 40 min, cool to room temperature, and determine the HMF concentration in the reaction system by HPLC. Combine with 1 the degree of acetyl substitution of cellulose acetate, the component of unused cigarette butt filter tips determined by 1H NMR, determine the molar mass of cellulose acetate, calculate the HMF yield. The specific experimental parameters and HMF yields are shown in Table 4.

[0042] It can be seen that aluminum chloride with different dosages can all catalyze the preparation of 5-hydroxymethylfurfural from cigarette butt filter tips; and when the mass ratio of cigarette butt filter tips to metal catalyst is 1:0.625 - 1:1.25 g / mmol, the 5-hydroxymethylfurfural reaches at least 48%.

[0043] Table 4. Effect of the dosage of metal catalyst on the HMF yield

[0044]

[0045] Example 5

[0046] Take 0.3 g of dried cigarette butt filter tips, 12 mL of acetone, and 3 mL of water and place them in a 25 mL reaction kettle. Add aluminum chloride to make its amount 0.1875 mmol. Under the condition of a magnetic stirring speed of 700 rpm, heat the reaction kettle to 160 °C by means of heat conduction heating, hold for 30 min, 40 min, 50 min, and 60 min respectively, cool to room temperature, and determine the HMF concentration in the reaction system by HPLC. Combine with 1 the degree of acetyl substitution of cellulose acetate, the component of unused cigarette butt filter tips determined by 1H NMR, determine the molar mass of cellulose acetate, calculate the HMF yield. The specific experimental parameters and HMF yields are shown in Table 5.

[0047] It can be seen that when the reaction time is 30 min, the yield of 5-hydroxymethylfurfural reaches 45%, and as the reaction time increases, the yield of 5-hydroxymethylfurfural also increases.

[0048] Table 5. Effect of reaction time on the HMF yield

[0049]

[0050] Example 6

[0051] Weigh 0.75 g and 1.2 g of dried cigarette butts filter tips (corresponding to substrate concentrations of 5% and 8% respectively), 12 mL of acetone, and 3 mL of water, and place them in a 25 mL reaction kettle. Add aluminum chloride to make its amount 0.1875 mmol or 0.375 mmol. Under the condition of a magnetic stirring speed of 1400 rpm, heat the reaction kettle to 160 °C by means of heat conduction heating, and keep it for 60 min or 70 min. Cool to room temperature, and use HPLC to measure the HMF concentration in the reaction system. Combine 1 the degree of acetyl substitution of cellulose acetate, the component of the unused cigarette butt filter tip determined by 1H NMR, determine the molar mass of cellulose acetate, calculate the HMF yield. The specific experimental parameters and HMF yield are shown in Table 6.

[0052] Table 6. Influence of reaction substrate concentration on HMF yield

[0053]

[0054] Example 7

[0055] A method for preparing 5-hydroxymethylfurfural from waste cigarette butt filter tips, comprising the following steps:

[0056] Step (1): Weigh 0.3 g of dried cigarette butt filter tips, 12 mL of acetone, and 3 mL of water, and place them in a 25 mL reaction kettle. Add 0.1875 mmol of aluminum chloride. Under the condition of a magnetic stirring speed of 700 rpm, heat the reaction kettle to 160 °C by means of heat conduction heating, and keep it for 50 min;

[0057] Step (2): After the reaction is completed, the reaction solution is rotary evaporated under reduced pressure at a temperature of 40 °C and a pressure of 100 mbar to recover acetone. Add activated carbon to the residual liquid (the dosage ratio of activated carbon to residual liquid is 1 g:15 mL), mix evenly, filter to remove impurities such as humin, and obtain a filtrate. Add methyl isobutyl ketone to the filtrate for extraction (the volume ratio of methyl isobutyl ketone to the filtrate is 1:1), separate to obtain an extraction phase (oil phase) and a raffinate phase (water phase). Add an equal volume of methyl isobutyl ketone to the raffinate phase again, and separate to obtain an extraction phase (oil phase). Combine the extraction phases extracted twice;

[0058] Step (3): The extraction phase is subjected to vacuum distillation at a temperature of 40 °C and a pressure of 50 mbar to obtain 5-hydroxymethylfurfural.

Claims

1. A method for preparing 5-hydroxymethylfurfural using waste cigarette butt filters, characterized in that: Including: Mix the cigarette butt filter, organic solvent and water evenly, add a metal salt catalyst, heat to the reaction temperature, and react to generate 5-hydroxymethylfurfural.

2. The method for preparing 5-hydroxymethylfurfural by using waste cigarette butt filters according to claim 1, wherein: The organic solvent is acetone; the volume ratio of the organic solvent to water is 9:1 to 1:9; the total volume of water and organic solvent to the volume-mass ratio of the cigarette butt filter is 100:1 to 10:1 mL / g.

3. The method for preparing 5-hydroxymethylfurfural by using waste cigarette butt filters according to claim 2, characterized in that: The volume ratio of the organic solvent to water is 7:3 to 4:1, preferably 4:1; the total volume of water and organic solvent to the volume-mass ratio of the cigarette butt filter is 100:2 to 100:5 mL / g.

4. The method for preparing 5-hydroxymethylfurfural by using waste cigarette butt filters according to claim 1, characterized in that: The metal salt catalyst is at least one of aluminum chloride, chromium chloride, and iron chloride.

5. The method for preparing 5-hydroxymethylfurfural using waste cigarette butt filters according to claim 1, wherein: The dosage ratio of the cigarette butt filter to the metal salt catalyst is 1:0.3125 to 1:2.5 g / mmol.

6. The method for preparing 5-hydroxymethylfurfural by using waste cigarette butt filters according to claim 5, characterized in that: The dosage ratio of the cigarette butt filter to the metal salt catalyst is 1:0.625 to 1:1.25 g / mmol.

7. The method for preparing 5-hydroxymethylfurfural by using waste cigarette butt filters according to claim 1, characterized in that: The reaction temperature is 130 to 180 °C, preferably 160 °C; the reaction time is 10 to 300 min, preferably 30 to 60 min.

8. The method for preparing 5-hydroxymethylfurfural by using waste cigarette butt filters according to claim 1, characterized in that: After the reaction is completed, the reaction solution is rotary evaporated under reduced pressure to recover the organic solvent. Activated carbon is added to the residual liquid, mixed evenly, and filtered; an extractant is added to the filtrate for extraction, and the extraction phase and the raffinate phase are separated. The same volume of extractant is added to the raffinate phase again, and the extraction phase is separated. The extraction phases obtained twice are combined; the extraction phase is purified by vacuum distillation or rectification to obtain 5-hydroxymethylfurfural.

9. The method for preparing 5-hydroxymethylfurfural by using waste cigarette butt filters according to claim 8, characterized in that: The conditions for vacuum distillation of the reaction solution are a temperature of 40 °C and a pressure of 100 mbar; The mass-volume ratio of the activated carbon to the residual liquid is 1:15 g / mL.

10. The method for preparing 5-hydroxymethylfurfural by using waste cigarette butt filters according to claim 9, characterized in that: The extractant is at least one of methyl isobutyl ketone and ethyl acetate; the volume ratio of the extractant to the filtrate is 1:1.

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