Quercetin modified lignin-based phenolic resin and preparation method thereof

Abstract

The invention discloses quercetin modified lignin-based phenolic resin and a preparation method thereof, the preparation method is simple in process, quercetin and lignin extracted from bio-based are used in the process, the sustainable development concept is met, and compared with lignin and quercetin, the quercetin has more active sites, lower molecular weight and ordered repetitive units, so that the quercetin modified lignin-based phenolic resin can be used for preparing a high-molecular-weight phenolic resin. Therefore, on the basis of the lignin-based phenolic resin, the toughness and heat resistance of the lignin-based phenolic resin are improved by introducing the natural biological phenol quercetin.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high polymer material synthesis, and particularly relates to a quercetin modified lignin-based phenolic resin and a preparation method thereof. BACKGROUND

[0002] Phenolic resin is a kind of high polymer synthetic resin prepared by polycondensation reaction of phenol (such as phenol) and aldehyde (such as formaldehyde) under the action of acid or base catalyst. As one of the three thermosetting resins, phenolic resin has continuously dominated the development of the resin industry since its first synthesis more than 100 years ago. Since the 1930s, products produced from phenolic resin, such as telephones, pipes, pen barrels, glue, optical materials, etc., have been widely used all over the world.

[0003] Although phenolic resin is widely used in the field of rubber, its raw material phenol is first distilled from coal tar, and then synthesized from isopropylene; formaldehyde is also derived from fossil products. From the perspective of green, non-toxic and sustainable development, both raw materials are not sustainable. Therefore, one of the main directions of the current development of phenolic resin is to find substitutes for phenol and formaldehyde.

[0004] Lignin is one of the most abundant natural aromatic substances on earth and has been regarded as an important renewable biological resource. Lignin itself has many aldehyde groups, alcohol hydroxyl groups and phenolic hydroxyl groups, so when lignin is used to synthesize phenolic resin, it can provide phenolic hydroxyl groups and aldehyde groups at the same time, thereby reducing the use of phenol and formaldehyde. However, this will reduce the performance of the resin, which cannot reach the level of traditional phenolic resin.

[0005] Natural quercetin belongs to natural aromatic compounds and has a wide source. Compared with lignin, quercetin has more active sites, lower molecular weight and ordered repeating units. In addition, the rigid structure of quercetin can play an important role in improving the toughness and thermal stability of phenolic resin.

[0006] Therefore, using quercetin to modify lignin-based phenolic resin is a possible innovative direction. Based on lignin-based phenolic resin, part of the quercetin is added to replace part of the phenol for condensation reaction, so as to produce more green and environmentally friendly high-performance phenolic resin. SUMMARY

[0007] The present application aims to provide a quercetin modified lignin-based phenolic resin and a preparation method thereof. The preparation method is simple, and bio-based quercetin and lignin are used in the process, which meets the concept of sustainable development. Compared with lignin, quercetin has more active sites, lower molecular weight and ordered repeating units. Therefore, by introducing natural biological phenol quercetin, the toughness and heat resistance of lignin-based phenolic resin are improved based on lignin-based phenolic resin.

[0008] The technical scheme discloses a quercetin modified lignin-based phenolic resin, and a structure is shown in the following formula (1). Formula (1), wherein n is an integer of 1-50, and m is an integer of 1-50.

[0009] Correspondingly, a preparation method of the quercetin modified lignin-based phenolic resin is also disclosed, and sequentially comprises the following steps. Step S1, lignin, phenol, quercetin and an alkaline catalyst are added into a three-necked flask, are uniformly stirred, the stirring speed is 100-200 rpm, and the lignin is phenolated by reacting at 90 DEG C for 90 min; Step S2, the temperature is lowered to 70 DEG C, a quantitative aqueous solution of an aldehyde compound is added dropwise, after the dropwise addition is completed, the reaction is carried out for 30 min, and then the temperature is raised to 95 DEG C and the reaction is carried out for 180 min; Step S3, the temperature is lowered to 65 DEG C, an acid termination agent is used to titrate to neutral, vacuum distillation is carried out for 120 min under reduced pressure, the vacuum degree is-0.085 kPa to-0.1 mPa, and the product of formula (1) is obtained after being cooled to room temperature.

[0010] Preferably, in the preparation method of the quercetin modified lignin-based phenolic resin, the aldehyde compound is one of formaldehyde, acetaldehyde, propyl aldehyde, butyl aldehyde and other short-chain aliphatic aldehydes, preferably formaldehyde, and the phenol-aldehyde ratio is 1:1-1.8, preferably 1:1.5-1.8.

[0011] Preferably, in the preparation method of the quercetin modified lignin-based phenolic resin, the lignin is at least one of guaiacyl lignin, syringyl lignin, p-hydroxyphenyl lignin, kraft lignin, lignin sulfonate, hydrolyzed lignin, soda lignin and organic solvent lignin, and the mass ratio of lignin to phenol is 1:1.0-2.0, preferably 1:1.4-1.6.

[0012] Preferably, in the preparation method of the quercetin modified lignin-based phenolic resin, the quercetin can be replaced by at least one of isoquercetin and dihydroquercetin, and the molar ratio of quercetin to phenol is 1:6-8, preferably 1:7.

[0013] Preferably, in the preparation method of the quercetin modified lignin-based phenolic resin, the acid termination agent comprises at least one of inorganic acid and organic acid, the inorganic acid comprises sulfuric acid, hydrobromic acid, phosphoric acid and hydrochloric acid, the organic acid comprises benzene sulfonic acid, dodecyl benzene sulfonic acid, p-methyl benzene sulfonic acid, xylene sulfonic acid, phenol sulfonic acid, chlorobenzene sulfonic acid and sodium sulfonate, and the molar ratio of the acid termination agent to the alkaline catalyst is 1:1.

[0014] Preferably, in the preparation method of the quercetin-modified lignin-based phenolic resin, the alkaline catalyst is at least one of an organic base, an alkali metal or a hydroxide, including triethylamine, diethylamine, potassium hydroxide, sodium hydroxide, and calcium hydroxide, and the mass ratio of the alkaline catalyst to phenol is 1:15-18, preferably 1:16-17.

[0015] The present application has the advantages of simple preparation process, use of biobased extracted quercetin and lignin, and compliance with the concept of sustainable development. Compared with lignin, quercetin has more active sites, lower molecular weight and ordered repeating units. Therefore, the present application improves the toughness and heat resistance of lignin phenolic resin by introducing natural biophenol quercetin based on lignin phenolic resin. DETAILED DESCRIPTION

[0016] The technical solutions in the embodiments of the present application will be described in detail below. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of the present application.

[0017] Embodiment 1

[0018] In a 500 mL four-necked round-bottom flask equipped with a stirrer, a thermometer, a reflux condenser and a dropping funnel, 100 g of phenol, 66.0 g of lignin and 13.6 g of quercetin were added, and the mixture was uniformly mixed by heating to 90℃, and then 6.0 g of sodium hydroxide was added. The reaction was carried out for 90 min, during which the temperature was strictly controlled at 90±1℃. After the reaction was completed, the temperature was lowered to 70℃, and 102.1 g of 50% formaldehyde aqueous solution was added in three portions, and the total dropping time was controlled at 120-150 min. After the dropping was completed, the reaction was carried out for 30 min. The temperature was raised to 95℃, and the reaction was carried out for 180 min, and then the temperature was lowered to 65℃, 6.7 g of hydrochloric acid was added, and the vacuum was slowly built to-95 kPa, and the reduced pressure distillation was carried out for 120 min, thereby obtaining the quercetin-modified lignin-based phenolic resin of formula (1). The SP of the resin is 105.0℃; the HPLC analysis shows that the mass fraction of free phenol in the resin is 0.02%.

[0019] Embodiment 2

[0020] In a 500ml four-necked round flask equipped with a stirrer, thermometer, reflux condenser and dropping funnel, 100g of phenol, 66.0g of lignosulfonate and 15.6g of dihydroquercetin were mixed at 90°C, and then 6.0g of triethylamine was added. The reaction was carried out for 90 minutes, during which the temperature was strictly controlled at 90±1°C. After the reaction was completed, the temperature was lowered to 70°C, and 102.1g of 50% butyraldehyde aqueous solution was added dropwise in three portions, with the total dropping time controlled at 120-150 minutes. After the dropping was completed, the reaction was carried out for 30 minutes. The temperature was raised to 95°C, and the reaction was carried out for 180 minutes. Then the temperature was lowered to 65°C, 6.7g of hydrochloric acid was added, and the vacuum was slowly built up to -95kPa. The vacuum distillation was carried out for 120 minutes, thus obtaining the quercetin-modified lignin-based phenol-formaldehyde resin of formula (1). The SP of the resin was 91.2°C. The HPLC analysis showed that the mass fraction of free phenol in the resin was 0.02%.

[0021] Example 3

[0022] In a 500ml four-necked round flask equipped with a stirrer, thermometer, reflux condenser and dropping funnel, 100g of phenol, 66.0g of lignosulfonate and 15.6g of dihydroquercetin were mixed at 90°C, and then 6.0g of triethylamine was added. The reaction was carried out for 90 minutes, during which the temperature was strictly controlled at 90±1°C. After the reaction was completed, the temperature was lowered to 70°C, and 102.1g of 50% butyraldehyde aqueous solution was added dropwise in three portions, with the total dropping time controlled at 120-150 minutes. After the dropping was completed, the reaction was carried out for 30 minutes. The temperature was raised to 95°C, and the reaction was carried out for 180 minutes. Then the temperature was lowered to 65°C, 6.7g of hydrochloric acid was added, and the vacuum was slowly built up to -95kPa. The vacuum distillation was carried out for 120 minutes, thus obtaining the quercetin-modified lignin-based phenol-formaldehyde resin of formula (1). The SP of the resin was 91.2°C. The HPLC analysis showed that the mass fraction of free phenol in the resin was 0.02%.

[0023] Example 4

[0024] In a 500ml four-necked round bottom flask equipped with a stirrer, thermometer, reflux condenser and dropping funnel, phenol 100g, lignin 66.0g, quercetin 13.6g were added, heated to 90°C and mixed uniformly, then sodium hydroxide 6.0g was added. The reaction was carried out for 90min, during which the temperature was strictly controlled at 90±1°C. After the reaction was completed, the temperature was lowered to 70°C, and 108.2g of 50% formaldehyde aqueous solution was added in three portions, and the total drop time was controlled at 120-150min. After the drop was completed, the reaction was carried out for 30min. The temperature was raised to 95°C, and the reaction was carried out for 180min, then the temperature was lowered to 65°C, 6.7g of hydrochloric acid was added, and the vacuum was slowly built to-95kPa, and the vacuum distillation was carried out for 120min, thus the quercetin modified lignin-based phenolic resin of formula (1) was obtained. The SP of the resin was 109.4°C; the HPLC analysis showed that the mass fraction of free phenol in the resin was 0.02%.

[0025] Example 5

[0026] In a 500ml four-necked round bottom flask equipped with a stirrer, thermometer, reflux condenser and dropping funnel, phenol 100g, lignin 66.0g, quercetin 13.6g were added, heated to 90°C and mixed uniformly, then sodium hydroxide 6.0g was added. The reaction was carried out for 90min, during which the temperature was strictly controlled at 90±1°C. After the reaction was completed, the temperature was lowered to 70°C, and 108.2g of 50% formaldehyde aqueous solution was added in three portions, and the total drop time was controlled at 120-150min. After the drop was completed, the reaction was carried out for 30min. The temperature was raised to 95°C, and the reaction was carried out for 180min, then the temperature was lowered to 65°C, 6.7g of hydrochloric acid was added, and the vacuum was slowly built to-95kPa, and the vacuum distillation was carried out for 120min, thus the quercetin modified lignin-based phenolic resin of formula (1) was obtained. The SP of the resin was 109.4°C; the HPLC analysis showed that the mass fraction of free phenol in the resin was 0.02%.

[0027] Example 6

[0028] In a 500ml four-necked round bottom flask equipped with a stirrer, thermometer, reflux condenser and dropping funnel, phenol 100g, lignin 70.0g, quercetin 13.6g, and sodium hydroxide 6.0g were added and mixed uniformly at 90°C. The reaction was carried out for 90 minutes, during which the temperature was strictly controlled at 90±1°C. After the reaction was completed, the temperature was lowered to 70°C, and 108.2g of 50% formaldehyde aqueous solution was added dropwise in three portions, with the total dropwise addition time controlled at 120-150 minutes. After the dropwise addition was completed, the reaction was carried out for 30 minutes. The temperature was raised to 95°C, and the reaction was carried out for 180 minutes. Then the temperature was lowered to 65°C, and 6.7g of hydrochloric acid was added. The vacuum was slowly built up to -95kPa, and the vacuum distillation was carried out for 120 minutes, thereby obtaining the quercetin-modified lignin-based phenolic resin of formula (1). The SP of the resin was 106.1°C. HPLC analysis showed that the mass fraction of free phenol in the resin was 0.02%.

[0029] Comparative Example 1 In a 500ml four-necked round bottom flask equipped with a stirrer, thermometer, reflux condenser and dropping funnel, phenol 100g, lignin 66.0g, and sodium hydroxide 6.0g were added and mixed uniformly at 90°C. The reaction was carried out for 90 minutes, during which the temperature was strictly controlled at 90±1°C. After the reaction was completed, the temperature was lowered to 70°C, and 102.1g of 50% formaldehyde aqueous solution was added dropwise in three portions, with the total dropwise addition time controlled at 120-150 minutes. After the dropwise addition was completed, the reaction was carried out for 30 minutes. The temperature was raised to 95°C, and the reaction was carried out for 180 minutes. Then the temperature was lowered to 65°C, and 6.7g of hydrochloric acid was added. The vacuum was slowly built up to -95kPa, and the vacuum distillation was carried out for 120 minutes, thereby obtaining the quercetin-modified lignin-based phenolic resin of formula (1). The SP of the resin was 89.5°C. HPLC analysis showed that the mass fraction of free phenol in the resin was 0.02%.

[0030] The phenolic reinforcing resins prepared in the examples were compared with Comparative Example 1 to evaluate their effects in rubber compositions. The effects of the resins on the properties of the rubber were verified by testing the vulcanization scorch properties. The compositions of the rubber compositions were as follows: Serial No. Component Name Mass Fraction 1 Natural rubber, NR 100 2 Carbon black N375 60 3 Process oil 3.4 4 Zinc oxide 4.0 5 Stearic acid 2.0 6 Phenolic reinforcing resin of the present invention 10.0 7 Sulfur 3.0 8 Hexamethylenetetramine 1.0 9 Accelerator N-tert-butyl-2-benzothiazole sulfenamide 2.0 10 Antioxidant 2,2,4-trimethyl-1,2-dihydroquinoline polymer 1.5 11 Protective wax 1.0 The physical and mechanical properties of the rubber compounds were tested after vulcanization at 151°C for 25 minutes, and the results were as follows: According to the physical and mechanical property data of the rubber compositions in the above table, the performance retention rates of the compounds before and after aging were compared. It can be seen that the performance retention rate of Comparative Example 1 after aging was poor, and the performance retention rate of Example 5 after aging was better, which proved that the change in the properties of the rubber products containing the resins of the present experiment due to heating was small, which was beneficial to improving the quality of the rubber products.

[0031] The embodiment only illustrates the patent and does not limit the protection scope of the patent, and the person skilled in the art can also make partial changes, as long as the changes do not exceed the spirit and essence of the patent, and are considered as equivalent replacement of the patent, and are within the protection scope of the patent.

Claims

1. A quercetin-modified lignin-based phenolic resin, characterized in that, The structure of quercetin-modified lignin-based phenolic resin is shown in formula (1) below: Equation (1), where n is an integer from 1 to 50 and m is an integer from 1 to 50.

2. The method for preparing quercetin-modified lignin-based phenolic resin according to claim 1, characterized in that, The steps are as follows: Step S1: Add lignin, phenol, quercetin and alkaline catalyst to a three-necked flask, stir evenly, and react at 100~200 rpm for 90 min at 90℃ to obtain phenolized lignin. Step S2: Cool down to 70°C, add a measured amount of aqueous solution of aldehyde compound dropwise, react for 30 min after the addition is complete, then heat up to 95°C and react for 180 min. Step S3: Cool down to 65°C, titrate to neutral using an acidic terminator, then distill under reduced pressure for 120 min at a vacuum of -0.085 kPa to -0.1 mPa. After cooling to room temperature, obtain the product of formula (1).

3. The method for preparing quercetin-modified lignin-based phenolic resin according to claim 2, characterized in that, The aldehyde compound is one of formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, and other short-chain aliphatic aldehydes, preferably formaldehyde, with a phenol-aldehyde ratio of 1:1-1.8, preferably 1:1.5-1.

8.

4. The method for preparing quercetin-modified lignin-based phenolic resin according to claim 2, characterized in that, The lignin is at least one of guaiac-based lignin, syringyl lignin, p-hydroxyphenyl lignin, sulfate lignin, lignin sulfonate, hydrolyzed lignin, soda lignin, and organic solvent lignin, and the mass ratio of lignin to phenol is 1:1.0-2.0, preferably 1:1.4-1.

6.

5. The method for preparing quercetin-modified lignin-based phenolic resin according to claim 2, characterized in that, The quercetin can be replaced by at least one of isoquercetin and dihydroquercetin, and the molar ratio of quercetin to phenol is 1:6-8, preferably 1:

7.

6. The method for preparing quercetin-modified lignin-based phenolic resin according to claim 2, characterized in that, The acidic terminator includes at least one inorganic acid and an organic acid, wherein the inorganic acid includes sulfuric acid, hydrobromic acid, phosphoric acid, and hydrochloric acid; and the organic acid includes benzenesulfonic acid, dodecylbenzenesulfonic acid, p-toluenesulfonic acid, xylenesulfonic acid, phenolsulfonic acid, chlorobenzenesulfonic acid, and sodium sulfonate, wherein the molar ratio of the acidic terminator to the basic catalyst is 1:

1.

7. The method for preparing quercetin-modified lignin-based phenolic resin according to claim 2, characterized in that, The alkaline catalyst is an organic base, alkali metal, or hydroxide, including at least one of triethylamine, diethylamine, potassium hydroxide, sodium hydroxide, and calcium hydroxide. The mass ratio of the alkaline catalyst to phenol is 1:15-18, preferably 1:16-17.

Images