阅读说明：本技术 一种活性交联蔗渣木聚糖/金花茶花莽草酸酯-g-NVP的合成方法 (Synthesis method of active cross-linked bagasse xylan/camellia nitidissima shikimate-g-NVP ) 是由 李和平 武晋雄 张海燕 郑光绿 杨莹莹 黄红霞 杨世军 邹志明 柴建啟 耿恺 于 2020-06-25 设计创作，主要内容包括：本发明公开了一种活性蔗渣木聚糖/金花茶花莽草酸酯-g-NVP功能性复合衍生物的合成方法。以蔗渣木聚糖和金花茶花为主要原料,N-乙烯基吡咯烷酮为单体,N,N-亚甲基双丙烯酰胺为交联剂,首先在水溶液中经过硫酸铵引发合成蔗渣木聚糖/金花茶花-g-NVP；然后在离子液体1-丁基-3-甲基咪唑氯盐中,以莽草酸为酯化剂,4-二甲氨基吡啶与钛酸四丁酯为复合催化剂,再经过催化酯化反应合成活性交联蔗渣木聚糖/金花茶花莽草酸酯-g-NVP。在多种活性基团的共同作用下,蔗渣木聚糖/金花茶花衍生物的溶解度和水溶性提高,在生物医药、精细化工、食品等领域具有较高的应用价值。(The invention discloses a method for synthesizing an active bagasse xylan/camellia nitidissima shikimate-g-NVP functional composite derivative. The method comprises the following steps of firstly, initiating synthesis of bagasse xylan/camellia chrysantha flower-g-NVP in an aqueous solution through ammonium persulfate by using bagasse xylan and camellia chrysantha flower as main raw materials, N-vinyl pyrrolidone as a monomer and N, N-methylene bisacrylamide as a cross-linking agent; then, in ionic liquid 1-butyl-3-methylimidazole chloride, using shikimic acid as an esterifying agent, using 4-dimethylaminopyridine and tetrabutyl titanate as a composite catalyst, and synthesizing active cross-linked bagasse xylan/camellia chrysantha shikimate-g-NVP through a catalytic esterification reaction. Under the combined action of various active groups, the solubility and the water solubility of the bagasse xylan/camellia chrysantha derivative are improved, and the bagasse xylan/camellia chrysantha derivative has higher application value in the fields of biological medicine, fine chemical industry, food and the like.)

1. A synthetic method of an active bagasse xylan/camellia nitidissima shikimate-g-NVP composite derivative is characterized by comprising the following specific steps:

(1) sequentially adding 20mL of analytically pure 1-methylimidazole and 35-40 mL of analytically pure n-butyl chloride into a 250mL single-neck flask provided with a magnetic stirrer, a thermometer and a reflux condenser, uniformly mixing at room temperature, heating to 80 ℃, and reacting for 30-40 hours under stirring to obtain light yellow viscous liquid;

(2) after the viscous liquid in the step (1) is naturally cooled, washing with 50-60 mL of analytically pure ethyl acetate for 2-3 times, and rotationally evaporating at 80 ℃ to remove residual ethyl acetate, so as to finally obtain 1-butyl-3-methylimidazolium chloride (namely [ Bmim ] Cl ionic liquid with a light yellow color for later use;

(3) placing 8-15 g of bagasse xylan in a vacuum constant-temperature drying oven at 50 ℃ for drying for 24 hours to obtain dry-based bagasse xylan;

(4) respectively weighing 5-10 g of dry bagasse xylan, 0.25-0.5 g of camellia chrysantha flower and 0.5-1 g N, adding N-methylene bisacrylamide into a 250mL four-neck flask, adding 30-40 mL of distilled water, heating to 40-70 ℃, and stirring and activating for 60 minutes;

(5) weighing 1-3 g of ammonium persulfate in a 50mL beaker, adding 10-20 mL of distilled water, stirring at room temperature for 5-10 minutes to obtain an initiator solution, and placing the initiator solution in a 100mL constant-pressure dropping funnel for later use;

(6) measuring 5-10 mL of analytically pure N-vinyl pyrrolidone (NVP) in a 50mL beaker, adding 10-20 mL of distilled water, stirring at room temperature for 1-3 minutes to obtain a monomer solution, and placing the monomer solution in a 100mL constant-pressure dropping funnel for later use;

(7) synchronously dropwise adding the initiator solution obtained in the step (5) and the monomer solution obtained in the step (6) into the uniformly mixed system obtained in the step (4), and controlling the dropwise adding within 3-5 hours to complete; continuing the reaction for 1 hour;

(8) standing the reaction solution obtained in the step (7), cooling to room temperature, washing with 40-50 mL of analytically pure absolute ethanol and 40-50 mL of analytically pure acetone in sequence, and performing suction filtration for 2-3 times to obtain a BX/GFC-g-NVP crude product;

(9) placing the crude product obtained in the step (8) into a Soxhlet extractor, adding 60-80 mL of analytically pure acetone, extracting for 48 hours, and then placing the crude product into a constant-temperature vacuum drying oven at 60 ℃ to dry for 24 hours to constant weight to obtain a graft copolymer BX/GFC-g-NVP;

(10) weighing 1-3 g of the graft copolymer BX/GFC-g-NVP obtained in the step (9), placing the graft copolymer BX/GFC-g-NVP into a 250mL four-neck flask with a stirrer and a thermometer, adding 10-20 g of the ionic liquid prepared in the step (2), and stirring for 30 minutes; then adding 3.5-6.5 g of shikimic acid, stirring uniformly, adding 0.4-1.2 g of 4-dimethylaminopyridine and 0.1-0.3 g of analytically pure tetrabutyl titanate, heating to 45-75 ℃ under stirring, continuing to perform reflux stirring reaction for 4.5-7.5 hours, and cooling the material to room temperature;

(11) and (3) washing the material obtained in the step (10) by using 30-40 mL of analytically pure absolute ethanol and 30-40 mL of analytically pure acetone in sequence, carrying out vacuum filtration for 2-3 times under reduced pressure, and drying the obtained filter cake in a constant-temperature vacuum drying oven at 60 ℃ for 24 hours to constant weight to obtain the active bagasse xylan/camellia chrysantha shikimate-g-NVP composite derivative.

Technical Field

The invention belongs to the technical field of fine chemical engineering, and particularly relates to a method for synthesizing active cross-linked bagasse xylan/camellia nitidissima shikimate-g-NVP.

Background

In recent years, the aging problem of the population in China is increasingly obvious, the incidence rate of malignant tumors is increased along with the increase of age, and the cancer is increasingly prominent as the main cause of death of the elderly. Tumors are always the key point for human resistance, and as the demand of people for antitumor drugs is continuously increased, the development of novel antitumor drugs becomes an important subject of domestic and foreign research.

At present, the antitumor drugs are mainly divided into chemotherapeutic drugs and molecular targeted drugs, wherein the chemotherapeutic drugs have strong toxic and side effects on normal cells and poor biocompatibility. The xylan is used as a natural polymer, has the characteristics of small toxic and side effects, good biocompatibility and the like, and has the effects of resisting cancer, regulating biological immunity and the like after chemical modification such as grafting, esterification and the like. However, hydroxyl groups in the xylan structure easily form hydrogen bonds, and the existence of the hydrogen bond network leads to the formation of a compact crystal structure, so that the xylan can hardly be dissolved in most solvents, has low reactivity and limits the application of the xylan. Research shows that the ionic liquid is used as a reaction solvent, so that hydrogen bonds of xylan can be destroyed, the solubility of xylan is increased, and the modification reaction of xylan is facilitated. Camellia nitidissima has the effects of resisting bacteria, oxidation and blood fat and inhibiting tumor growth, is compounded with xylan, and is subjected to grafting modification reaction by taking N-vinyl pyrrolidone (NVP) as a grafting monomer, so that the antitumor activity can be enhanced. The graft copolymerization product of the bagasse xylan and the camellia chrysantha improves the water solubility and the activity of the bagasse xylan. Shikimic acid itself has anti-inflammatory and analgesic effects, and is generally used as a basic material for synthesizing bioactive compounds such as antibiotics, antitumor drugs and antithrombotic drugs, and also can be used as an intermediate of antiviral and anticancer drugs. The bagasse xylan/camellia chrysantha-g-NVP is subjected to esterification modification in the ionic liquid by taking shikimic acid as an esterifying agent, the tendency of forming a hydrogen bond network by the bagasse xylan is further reduced, the solubility of a final product in the ionic liquid is greatly improved compared with that of the xylan, the water solubility is correspondingly improved, the product can be better dispersed along with blood after entering a human body, the absorption of the organism to medicines is promoted, the original activity of active groups is retained, and the product can be applied to the fields of biological medicines, foods, cosmetics, functional materials and the like.

The method comprises the steps of taking Bagasse Xylan (BX) and camellia chrysantha (GFC) as main raw materials, taking N-vinyl pyrrolidone as a monomer, taking N, N-methylene bisacrylamide as a cross-linking agent, and initiating synthesis of the bagasse xylan/camellia chrysantha flower-g-NVP in an aqueous solution by ammonium persulfate; then, in ionic liquid 1-butyl-3-methylimidazole chloride salt ([ Bmim ] Cl), using shikimic acid as an esterifying agent, using 4-dimethylaminopyridine and tetrabutyl titanate as a composite catalyst, and synthesizing active cross-linked bagasse xylan/camellia nitidissima shikimate-g-NVP through a catalytic esterification reaction.

Disclosure of Invention

The invention aims to improve the bioactivity of bagasse xylan and provides a synthetic method of actively-linked bagasse xylan/camellia nitidissima shikimate-g-NVP.

The method comprises the following specific steps:

(1) adding 20mL of analytically pure 1-methylimidazole and 35-40 mL of analytically pure n-butyl chloride into a 250mL single-neck flask provided with a magnetic stirrer, a thermometer and a reflux condenser in sequence, uniformly mixing at room temperature, heating to 80 ℃, and stirring for reacting for 30-40 hours to obtain light yellow viscous liquid.

(2) And (2) after the viscous liquid in the step (1) is naturally cooled, washing with 50-60 mL of analytically pure ethyl acetate for 2-3 times, and rotationally evaporating at 80 ℃ to remove residual ethyl acetate to finally obtain the light yellow 1-butyl-3-methylimidazolium chloride ([ Bmim ] Cl) ionic liquid for later use.

(3) And (3) drying 8-15 g of bagasse xylan in a vacuum constant-temperature drying oven at 50 ℃ for 24 hours to obtain the dry-based bagasse xylan.

(4) Respectively weighing 5-10 g of dry bagasse xylan, 0.25-0.5 g of camellia chrysantha and 0.5-1 g N, adding N-methylene bisacrylamide into a 250mL four-neck flask, adding 30-40 mL of distilled water, heating to 40-70 ℃, and stirring and activating for 60 minutes.

(5) Weighing 1-3 g of ammonium persulfate in a 50mL beaker, adding 10-20 mL of distilled water, stirring at room temperature for 5-10 minutes to obtain an initiator solution, and placing the initiator solution in a 100mL constant-pressure dropping funnel for later use.

(6) Measuring 5-10 mL of analytically pure N-vinyl pyrrolidone (NVP) in a 50mL beaker, adding 10-20 mL of distilled water, stirring at room temperature for 1-3 minutes to obtain a monomer solution, and placing the monomer solution in a 100mL constant-pressure dropping funnel for later use.

(7) Synchronously dropwise adding the initiator solution obtained in the step (5) and the monomer solution obtained in the step (6) into the uniformly mixed system obtained in the step (4), and controlling the dropwise adding within 3-5 hours to complete; the reaction was continued for 1 hour.

(8) And (3) standing the reaction liquid obtained in the step (7), cooling to room temperature, washing with 40-50 mL of analytically pure absolute ethanol and 40-50 mL of analytically pure acetone in sequence, and performing suction filtration for 2-3 times to obtain a BX/GFC-g-NVP crude product.

(9) And (3) placing the crude product obtained in the step (8) into a Soxhlet extractor, adding 60-80 mL of analytically pure acetone, extracting for 48 hours, and then placing the crude product into a constant-temperature vacuum drying oven at 60 ℃ to dry for 24 hours to constant weight to obtain the graft copolymer BX/GFC-g-NVP.

(10) Weighing 1-3 g of the graft copolymer BX/GFC-g-NVP obtained in the step (9), placing the graft copolymer BX/GFC-g-NVP into a 250mL four-neck flask with a stirrer and a thermometer, adding 10-20 g of the ionic liquid prepared in the step (2), and stirring for 30 minutes; then adding 3.5-6.5 g of shikimic acid, stirring uniformly, adding 0.4-1.2 g of 4-dimethylaminopyridine and 0.1-0.3 g of analytically pure tetrabutyl titanate, heating to 45-75 ℃ under stirring, continuing to perform reflux stirring reaction for 4.5-7.5 hours, and cooling the material to room temperature.

(11) And (3) washing the material obtained in the step (10) by using 30-40 mL of analytically pure absolute ethanol and 30-40 mL of analytically pure acetone in sequence, carrying out vacuum filtration for 2-3 times under reduced pressure, and drying the obtained filter cake in a constant-temperature vacuum drying oven at 60 ℃ for 24 hours to constant weight to obtain the active bagasse xylan/camellia chrysantha shikimate-g-NVP composite derivative.

(12) The carboxylic acid esterification substitution degree of the bagasse xylan/camellia chrysantha shikimate-g-NVP composite derivative is measured by an acid-base titration method, and the operation method is as follows: about 0.5g of the product sample was accurately weighed into a 250mL Erlenmeyer flask, 5mL of distilled water was added, and several drops of phenolphthalein indicator were added dropwise. 2.5mL of 0.5mol/L sodium hydroxide solution was added, shaken well, and saponified for 1 hour at 20 ℃. The stopper and the inner wall of the conical flask are washed by 10mL of deionized water, and then the end point is obtained by titrating to colorless by using 0.5mol/L hydrochloric acid standard solution. Recording the volume V of the standard solution of hydrochloric acid consumed₁. Under the same condition, carrying out blank titration by using bagasse xylan/camellia chrysantha-g-NVP before esterification, and recording the volume V of the standard solution consuming hydrochloric acid₀. The calculation formula of the carboxylic acid esterification substitution Degree (DS) is as follows:

in the formula: wc — mass fraction of ester-containing carbonyl groups in the target product,%;

V₀-blank experiments using the volume of hydrochloric acid standard solution in mL;

V₁titration of the volume of the standard solution of hydrochloric acid used for the target product, in mL;

C_HCl-hydrochloric acid standard solution concentration, in mol/L;

m is the mass of the sample in g;

m-the relative molecular mass of shikimoyl;

132-relative molecular mass of bagasse xylan dewatering units;

DS-degree of ester carbonyl substitution.

(13) The method for measuring the solubility of the bagasse xylan/camellia nitidissima shikimate-g-NVP composite derivative comprises the following steps: accurately weighing 10g of 1-butyl-3-methylimidazolium chloride ([ Bmim ] Cl) ionic liquid in three 250mL round-bottom flasks, and sealing; putting a 250mL round-bottom flask into an oil bath, adding the target product bagasse xylan/camellia chrysantha shikimate-g-NVP, wherein the adding amount is 1g (1g/mol IL) of ionic liquid per mole, stirring and dissolving for 1 hour at constant temperature under sealing, and checking whether the xylan is completely dissolved by using a polarizing microscope. When the target product is completely dissolved, the target product is continuously added until saturation is reached, the mass of the target product added at the moment is recorded, and the solubility of the target product at the temperature is calculated, wherein the unit is the mass (g/mol IL) of the target product dissolved in each mol of the ionic liquid. The temperature range for solubility measurements was 45-75 ℃ with 5 ℃ intervals.

The bagasse xylan/camellia chrysantha shikimate-g-NVP functional composite derivative with bioactivity is synthesized through two-step reactions of grafting and esterification, the substitution degree of the product is high, the solubility performance is excellent, the production process condition is easy to control, the cost is low, and the application value in the fields of biomedicine, fine chemical engineering, food and the like is high.

Drawings

FIG. 1 is an SEM photograph of raw bagasse xylan.

FIG. 2 is an SEM photograph of bagasse xylan/Camellia nitidissima shikimate-g-NVP derivative.

FIG. 3 is an IR chart of original bagasse xylan/Camellia nitidissima flower.

FIG. 4 is an IR picture of bagasse xylan/Camellia nitidissima shikimate-g-NVP derivative.

Figure 5 is an XRD pattern of raw bagasse xylan.

FIG. 6 is an XRD diagram of bagasse xylan/camellia nitidissima shikimate-g-NVP functional composite derivative.

Detailed Description