阅读说明：本技术 一种用于植物生长促进剂的聚天冬氨酸钾的制备方法 (Preparation method of polyaspartic acid potassium for plant growth promoter ) 是由 不公告发明人 于 2020-11-26 设计创作，主要内容包括：本发明涉及农业领域,具体关于一种用于植物生长促进剂的聚天冬氨酸钾的制备方法；本发明采用一种金属杂化高酸载量的固体酸作为合成聚天冬氨酸钾的催化剂,避免了液体强酸硫酸或磷酸的使用对生产设备造成的损坏,也去除掉了为除去这些催化剂所必须的洗涤,干燥等步骤,节约了成本,缩短了生产周期；另外本发明的金属杂化高酸载量的固体酸含有铁掺杂的磷酸铌,在制备聚琥珀酰亚胺过程中表现出较好的催化活性,能在较短的反应时间内达到较高的转化率,实现收率的提高和生产周期的缩短；本发明制备的植物生长促进剂的聚天冬氨酸钾对于植物对肥料的吸收能够起到富集、促进植物吸收养分的功能,对于种子的发芽,提高产量和果实质量上都有很好的效果。(The invention relates to the field of agriculture, in particular to a preparation method of polyaspartic acid potassium for a plant growth promoter; the invention adopts a metal hybridized high acid-carrying solid acid as the catalyst for synthesizing the potassium polyaspartate, avoids the damage to production equipment caused by the use of liquid strong acid sulfuric acid or phosphoric acid, also removes the steps of washing, drying and the like which are necessary for removing the catalysts, saves the cost and shortens the production period; in addition, the metal-hybridized high-acid-loading solid acid contains iron-doped niobium phosphate, shows better catalytic activity in the process of preparing polysuccinimide, can achieve higher conversion rate in shorter reaction time, and realizes the improvement of yield and the shortening of production period; the polyaspartic acid potassium of the plant growth promoter prepared by the invention can play a role in enriching the fertilizer absorption of plants and promoting the nutrient absorption of plants, and has good effects on seed germination, yield improvement and fruit quality improvement.)

1. A method for preparing polyaspartic acid potassium used for plant growth promoter, its concrete scheme is as follows:

adding 100-180 parts of L-aspartic acid and 0.5-10 parts of solid acid catalyst into a reaction kettle according to the mass parts, controlling the temperature to 180-220 ℃, carrying out stirring condensation reaction for 2-6h, then cooling to room temperature, filtering to remove the solid acid catalyst, then precipitating the reactant in pure water, filtering and drying to obtain polysuccinimide; adding 150 parts of the obtained polysuccinimide 100-parts into a reaction kettle, adding 40-60 parts of 10-20% potassium hydroxide solution by mass, heating to 60-80 ℃ under the protection of inert gas, carrying out hydrolysis reaction for 20-60min, cooling to room temperature, adjusting the pH value to be neutral by using an acid solution, adding 20-30 parts of cyclic silicon-based chitosan and 2-5 parts of citric acid, stirring at 60-80 ℃ for 120-160min, adding 500 parts of ethanol 300-parts into the reaction kettle, precipitating, filtering, washing, drying and crushing to obtain the potassium polyaspartate for the plant growth promoter.

2. The method of claim 1, wherein the preparation method of polyaspartic acid potassium used as plant growth promoter comprises the following steps: the solid acid catalyst is a metal hybrid solid acid catalyst with high acid loading capacity, and the preparation method comprises the following steps:

50-80 parts by mass of dried plant materials are crushed to 20-100 meshes, then the dried plant materials are mixed with 240 parts by mass of concentrated sulfuric acid 150, the mixture is stirred and reacted for 5-10 hours at room temperature, the mixture is heated to 180 ℃ after the reaction is finished, the reaction lasts for 8-14 hours, the mixture is filtered after the reaction is finished, the obtained 5-10 parts of solid water are washed and then added into 50-80 parts of hybrid modified solution, the mixture is uniformly mixed and then added into a high-pressure reaction kettle, the temperature is controlled to 140 ℃ and 160 ℃, the reaction lasts for 10-20 hours, the mixture is filtered after the reaction is finished, and the mixture is washed and then calcined for 3-7 hours at 600 ℃ under the protection of nitrogen; after the preparation, the metal hybrid solid acid catalyst with high acid loading can be obtained.

3. The method of claim 2, wherein the preparation method of polyaspartic acid potassium used as plant growth promoter comprises the following steps: the hybridization modification solution contains 0.1-0.5mol/L of niobium citrate, 0.05-0.3mol/L of ferric nitrate and 0.3-0.8mol/L of phosphoric acid.

4. The method of claim 2, wherein the preparation method of polyaspartic acid potassium used as plant growth promoter comprises the following steps: the plant material is corncob, coconut husk or poplar sawdust.

5. The method of claim 2, wherein the preparation method of polyaspartic acid potassium used as plant growth promoter comprises the following steps: the moisture content of the plant material is not more than 5%.

6. The method of claim 1, wherein the preparation method of polyaspartic acid potassium used as plant growth promoter comprises the following steps: the inert gas is high-purity nitrogen or high-purity argon.

7. The method of claim 1, wherein the preparation method of polyaspartic acid potassium used as plant growth promoter comprises the following steps: the acid solution is a hydrochloric acid solution with the mass percentage concentration of 1% -5%.

8. The method of claim 1, wherein the preparation method of polyaspartic acid potassium used as plant growth promoter comprises the following steps: the polyaspartic acid potassium is used as a plant growth promoter and is added into a chemical fertilizer according to the amount of 0.5-5% by weight, so that the utilization rate of crops to the chemical fertilizer is improved.

9. The method of preparing poly (potassium aspartate) for plant growth promoter according to claim 1, wherein said cyclic silicon-based chitosan is prepared by:

step one, adding 22-30 parts of chitosan, 150-180 parts of tetrahydrofuran, 2-6 parts of 2-bromoisobutyryl bromide and 0.5-2.5 parts of trimethylamine into a reaction kettle, introducing nitrogen, controlling the temperature to be 40-60 ℃, stirring and reacting for 90-120min, filtering and drying to obtain a product 1;

step two, uniformly mixing 3-7 parts of 2,4, 6-tripropenyloxy-1, 3, 5-triazine, 1-3.4 parts of 1,3,5, 7-tetramethylcyclotetrasiloxane, 0.02-0.2 part of tin octylate, 0.03-0.07 part of chloroplatinic acid and 100 parts of DMF (dimethyl formamide), heating to 67-74 ℃, and reacting for 1-5 hours to obtain a mixed product 2;

and step three, adding 25-34 parts of the product 1 into the mixed product 2, adding 3-7 parts of cuprous bromide, 0.8-2.5 parts of ammonium persulfate and 1.8-3.2 parts of cardanol, heating to 60-70 ℃, reacting for 15-20h, filtering the product, washing with methanol, and drying to obtain the cyclosilyl chitosan.

Technical Field

The invention relates to the field of agriculture, in particular to a preparation method of polyaspartic acid potassium for a plant growth promoter.

Background

The externally applied plant hormone can also regulate the growth and development process of plants, but the content of the plant hormone is low, and the extraction of the plant hormone from the plant is expensive, so that the application of the plant hormone in agriculture is limited. Now, chemical substances with similar structure and activity to plant hormones can be extracted through artificial synthesis or microbial fermentation, and the substances can also affect the growth and development of plants after being applied to the plants. Among them, substances capable of promoting plant growth are called plant growth promoters. The plant growth promoter can stimulate cell division and differentiation, promote plant stem elongation, and promote plant growth of vegetative organ and reproductive organ.

CN104781215A relates to the use of porous silica particles comprising porous silica containing particulate metallic elements as a plant growth promoter. The invention also relates to a granular composition comprising a carrier material and one or more spherical porous silica particles embedded in said carrier material, wherein each spherical porous silica particle comprises spherical porous silica comprising particulate silver, and to the use of said granular composition as a plant growth promoter.

CN102076218A A plant growth promoter of the present invention comprises, as an active ingredient, a tetrazolyloxime derivative represented by the following formula (1) (wherein X represents a halogen atom or the like, n represents any integer of 0 to 5, A represents a tetrazolyl group substituted with an alkyl group, and Het represents an optionally substituted pyridyl group or an optionally substituted thiazolyl group).

CN111212571A relates to a plant growth promoter which comprises a lignocellulosic biomass (a) and at least 1 base (B) selected from the following (B1) to (B3), and has a contact angle with water of 80 ° or less. < base (B) > (B1) resin acid; (B2) a compound represented by the formula (1), R1-Z1-Z2(1) [ wherein: r1: hydrocarbon group having 9 or more carbon atoms, Z1: a single bond OR (OR2) p, R2: an alkanediyl group having 2 or more and 3 or less carbon atoms, p: a number exceeding 0 and being 30 or less on average, Z2: a group selected from carboxyl, hydroxyl, sulfate and NR3R4, R3, R4: each independently a hydrogen atom, methyl, ethyl, or (R5O) qH, R5: an alkanediyl group having 2 or more and 3 or less carbon atoms, q: a number exceeding 0 on average and 15 or less ]; (B3) polyols or polycarboxylic acids having a molecular weight of 3 ten thousand or less.

The polyaspartic acid is a biodegradable high polymer material, has multiple functions of slow release, scale inhibition, moisture preservation and the like, and has very wide application prospects in many fields. It is also realized that the polyaspartic acid compound can play a role in enriching and promoting the absorption of nutrients by plants, and is an environment-friendly plant growth promoter. In the prior art, phosphoric acid or sulfuric acid is generally used as a catalyst in the synthesis process of the polyaspartic acid potassium, so that the problems of equipment corrosion and process complexity are inevitably caused, the production cost of the polyaspartic acid potassium is increased, and the application of the product is limited.

Disclosure of Invention

In order to solve the above problems, the present invention provides a method for preparing polyaspartic acid potassium for a plant growth promoter.

A method for preparing polyaspartic acid potassium used for plant growth promoter, its concrete scheme is as follows:

adding 100-180 parts of L-aspartic acid and 0.5-10 parts of solid acid catalyst into a reaction kettle according to the mass parts, controlling the temperature to 180-220 ℃, carrying out stirring condensation reaction for 2-6h, then cooling to room temperature, filtering to remove the solid acid catalyst, then precipitating the reactant in pure water, filtering and drying to obtain polysuccinimide; adding 150 parts of the obtained polysuccinimide 100-parts into a reaction kettle, adding 40-60 parts of potassium hydroxide solution with the mass percentage concentration of 10-20%, heating to 60-80 ℃ under the protection of inert gas, carrying out hydrolysis reaction for 20-60min, cooling to room temperature, adjusting the pH value to be neutral by using an acid solution, adding 20-30 parts of cyclic silicon-based chitosan and 2-5 parts of citric acid, stirring at 60-80 ℃ for 120-160min, adding 500 parts of ethanol 300-parts into the reaction kettle, precipitating, filtering, washing, drying and crushing to obtain the potassium polyaspartate for the plant growth promoter.

The solid acid catalyst is a metal hybrid solid acid catalyst with high acid loading capacity, and the preparation method comprises the following steps:

50-80 parts by mass of dried plant materials are crushed to 20-100 meshes, then the dried plant materials are mixed with 240 parts by mass of concentrated sulfuric acid 150, the mixture is stirred and reacted for 5-10 hours at room temperature, the mixture is heated to 180 ℃ after the reaction is finished, the reaction lasts for 8-14 hours, the mixture is filtered after the reaction is finished, the obtained 5-10 parts of solid water are washed and then added into 50-80 parts of hybrid modified solution, the mixture is uniformly mixed and then added into a high-pressure reaction kettle, the temperature is controlled to 140 ℃ and 160 ℃, the reaction lasts for 10-20 hours, the mixture is filtered after the reaction is finished, and the mixture is washed and then calcined for 3-7 hours at 600 ℃ under the protection of nitrogen; after the preparation, the metal hybrid solid acid catalyst with high acid loading can be obtained.

The preparation method of the cyclosiloxane chitosan comprises the following steps:

step one, adding 22-30 parts of chitosan, 150-180 parts of tetrahydrofuran, 2-6 parts of 2-bromoisobutyryl bromide and 0.5-2.5 parts of trimethylamine into a reaction kettle, introducing nitrogen, controlling the temperature to be 40-60 ℃, stirring and reacting for 90-120min, filtering and drying to obtain a product 1;

step two, uniformly mixing 3-7 parts of 2,4, 6-tripropenyloxy-1, 3, 5-triazine, 1-3.4 parts of 1,3,5, 7-tetramethylcyclotetrasiloxane, 0.02-0.2 part of tin octylate, 0.03-0.07 part of chloroplatinic acid and 100 parts of DMF (dimethyl formamide), heating to 67-74 ℃, and reacting for 1-5 hours to obtain a mixed product 2;

and step three, adding 25-34 parts of the product 1 into the mixed product 2, adding 3-7 parts of cuprous bromide, 0.8-2.5 parts of ammonium persulfate and 1.8-3.2 parts of cardanol, heating to 60-70 ℃, reacting for 15-20h, filtering the product, washing with methanol, and drying to obtain the cyclosilyl chitosan.

The chitosan and 2-bromoisobutyryl bromide in the first step firstly generate acetyl bromide chitosan, and the partial reaction equation is shown as follows:

step two, 2,4, 6-tripropenoxy-1, 3, 5-triazine and 1,3,5, 7-tetramethylcyclotetrasiloxane are subjected to hydrosilylation reaction, and the partial reaction equation is shown as follows:

thirdly, carrying out copolymerization reaction on the product obtained in the first step and the product obtained in the second step to obtain the cyclic silicon-based chitosan:

further, the cyclosilicon-based chitosan and the polyaspartic acid are further reacted to obtain the fertilizer synergistic controlled-release agent modified polyaspartic acid potassium.

The hybridization modification solution contains 0.1-0.5mol/L of niobium citrate, 0.05-0.3mol/L of ferric nitrate and 0.3-0.8mol/L of phosphoric acid.

The plant material is corncob, coconut husk or poplar sawdust.

The moisture content of the plant material is not more than 5%.

The inert gas is high-purity nitrogen or high-purity argon.

The acid solution is a hydrochloric acid solution with the mass percentage concentration of 1% -5%.

The polyaspartic acid potassium is used as a plant growth promoter and is added into a chemical fertilizer according to the amount of 0.5-5% by weight, so that the utilization rate of crops to the chemical fertilizer is improved.

According to the preparation method of the polyaspartic acid potassium for the plant growth promoter, disclosed by the invention, the solid acid with high acid loading capacity of metal hybridization is used as a catalyst for synthesizing the polyaspartic acid potassium, so that the damage to production equipment caused by the use of liquid strong acid sulfuric acid or phosphoric acid is avoided, the steps of washing, drying and the like which are necessary for removing the catalyst are also removed, the cost is saved, and the production period is shortened; in addition, the metal-hybridized high-acid-loading solid acid contains iron-doped niobium phosphate, shows better catalytic activity in the process of preparing polysuccinimide, can achieve higher conversion rate in shorter reaction time, and realizes the improvement of yield and the shortening of production period;

the polyaspartic acid potassium of the plant growth promoter prepared by the invention further reacts with the polyaspartic acid, has the functions of enriching the fertilizer absorbed by plants and promoting the plants to absorb nutrients, and has good effects on seed germination, yield improvement and fruit quality improvement.

Drawings

FIG. 1 is a Fourier infrared spectrum of potassium polyaspartate for plant growth promoting agent prepared in example 2:

at 1662cm^-1The telescopic absorption peak of carbonyl group of amide existing in the vicinity thereof was 1302cm^-1An expansion and contraction absorption peak of a carbon-nitrogen single bond at 3377/1596cm^-1The expansion/angle change absorption peak of the nitrogen hydrogen bond exists nearby and is 2929cm^-1The absorption peak of the carbon-hydrogen bond is at 1456cm^-1A telescopic absorption peak of carboxylate ions is present nearby and is 931cm^-1The out-of-plane bending absorption peak of the carboxyl hydroxyl exists nearby, which indicates that the potassium polyaspartate used for the plant growth promoter is successfully prepared.

Detailed Description

The invention is further illustrated by the following specific examples:

the following examples calculate the yield of potassium polyaspartate for each reaction according to the charge of L-aspartic acid; the plant growth promoting effect of the prepared polyaspartic acid potassium is tested by the germination rate of mung beans, 100g of mung beans with the preservation period not exceeding one year are weighed, the mung beans are soaked in a polyaspartic acid potassium solution with the mass percentage concentration of 0.1% for 12 hours, then the mung beans are spread on a towel, the polyaspartic acid potassium solution is sprayed for 3 times every day, and the germination rate of the mung beans within 48 hours is counted.

Example 1

A method for preparing polyaspartic acid potassium used for plant growth promoter, its concrete scheme is as follows:

adding 100g of L-aspartic acid and 0.5g of solid acid catalyst into a reaction kettle, controlling the temperature to 180 ℃, stirring for condensation reaction for 2 hours, then cooling to room temperature, filtering to remove the solid acid catalyst, then precipitating the reactant in pure water, filtering and drying to obtain polysuccinimide; and then adding 100g of polysuccinimide into a reaction kettle, adding 40g of potassium hydroxide solution with the mass g of 10%, heating to 60 ℃ under the protection of inert gas, carrying out hydrolysis reaction for 20min, then cooling to room temperature, adjusting the pH value to be neutral by using an acid solution, adding 20g of cyclic silicon-based chitosan and 2g of citric acid, stirring for 120min at 60 ℃, adding 300g of ethanol into the reaction kettle, precipitating, filtering, washing, drying and crushing to obtain the potassium polyaspartate for the plant growth promoter.

The solid acid catalyst is a metal hybrid solid acid catalyst with high acid loading capacity, and the preparation method comprises the following steps:

crushing 50g of dried plant material to 20 meshes, mixing with 150g of concentrated sulfuric acid, stirring at room temperature for 5 hours for reaction, heating the mixture to 140 ℃ after the reaction is finished, reacting for 8 hours, filtering after the reaction is finished, washing 5g of obtained solid, adding the washed solid into 50g of hybrid modified solution, uniformly mixing, adding the obtained solid into a high-pressure reaction kettle, controlling the temperature at 140 ℃ for reaction for 10 hours, filtering after the reaction is finished, and calcining at 300 ℃ for 3 hours under the protection of nitrogen after the washing is finished; after the preparation, the metal hybrid solid acid catalyst with high acid loading can be obtained.

The preparation method of the cyclosiloxane chitosan comprises the following steps:

step one, adding 22g of chitosan, 150g of tetrahydrofuran, 2g of 2-bromoisobutyryl bromide and 0.5g of trimethylamine into a reaction kettle, introducing nitrogen, controlling the temperature to be 40 ℃, stirring for reaction for 90min, filtering and drying to obtain a product 1;

step two, uniformly mixing 3g of 2,4, 6-tripropenyloxy-1, 3, 5-triazine, 1g of 1,3,5, 7-tetramethylcyclotetrasiloxane, 0.02g of tin octylate, 0.03g of chloroplatinic acid and 100g of DMF in a reaction kettle, and then heating to 67 ℃ for reaction for 1h to obtain a mixed product 2;

and step three, adding 25g of the product 1 into the mixed product 2, adding 3g of cuprous bromide, 0.8g of ammonium persulfate and 1.8g of cardanol, heating to 60 ℃, reacting for 15h, filtering, washing with methanol, and drying to obtain the cyclic silicon-based chitosan.

The hybridization modification solution contains 0.1mol/L of niobium citrate, 0.05mol/L of ferric nitrate and 0.3mol/L of phosphoric acid.

The plant material is corncob.

The water content of the plant material is 3.2%.

The inert gas is high-purity nitrogen.

The acid solution is a hydrochloric acid solution with the mass g of 1%.

Example 2

A method for preparing polyaspartic acid potassium used for plant growth promoter, its concrete scheme is as follows:

adding 140g of L-aspartic acid and 5g of solid acid catalyst into a reaction kettle, controlling the temperature to 200 ℃, stirring for condensation reaction for 4 hours, cooling to room temperature, filtering to remove the solid acid catalyst, precipitating the reactant in pure water, filtering, and drying to obtain polysuccinimide; adding 130g of polysuccinimide into a reaction kettle, adding 50g of potassium hydroxide solution with the mass g of 15%, heating to 70 ℃ under the protection of inert gas, carrying out hydrolysis reaction for 40min, cooling to room temperature, adjusting the pH value to be neutral by using an acid solution, adding 25g of cyclic silicon-based chitosan and 3g of citric acid, stirring for 140min at 70 ℃, adding 400g of ethanol into the reaction kettle, precipitating, filtering, washing, drying and crushing to obtain the potassium polyaspartate for the plant growth promoter.

The solid acid catalyst is a metal hybrid solid acid catalyst with high acid loading capacity, and the preparation method comprises the following steps:

crushing 65g of dried plant material to 80 meshes, mixing with 180g of concentrated sulfuric acid, stirring at room temperature for 8 hours, heating the mixture to 160 ℃ after the mixture is completed, reacting for 12 hours, filtering after the reaction is completed, washing 8g of obtained solid, adding the washed solid into 70g of hybrid modified solution, uniformly mixing, adding the obtained solid into a high-pressure reaction kettle, controlling the temperature to be 15 ℃, reacting for 15 hours, filtering after the reaction is completed, and calcining for 5 hours at 400 ℃ under the protection of nitrogen after the washing; after the preparation, the metal hybrid solid acid catalyst with high acid loading can be obtained.

The preparation method of the cyclosiloxane chitosan comprises the following steps:

step one, adding 25g of chitosan, 170g of tetrahydrofuran, 4g of 2-bromoisobutyryl bromide and 1g of trimethylamine into a reaction kettle, introducing nitrogen, controlling the temperature to be 55 ℃, stirring for reaction for 100min, filtering and drying to obtain a product 1;

step two, uniformly mixing 4g of 2,4, 6-tripropenyloxy-1, 3, 5-triazine, 2.2g of 1,3,5, 7-tetramethylcyclotetrasiloxane, 0.08g of tin octylate, 0.05g of chloroplatinic acid and 120g of DMF in a reaction kettle, heating to 70 ℃, and reacting for 3 hours to obtain a mixed product 2;

and step three, adding 28g of the product 1 into the mixed product 2, adding 4g of cuprous bromide, 1g of ammonium persulfate and 2.4g of cardanol, heating to 65 ℃, reacting for 16 hours, filtering, washing with methanol and drying to obtain the cyclic silicon-based chitosan.

The hybridization modification solution contains 0.3mol/L of niobium citrate, 0.15mol/L of ferric nitrate and 0.5mol/L of phosphoric acid.

The plant material is coconut peel.

The water content of the plant material is 3.1%.

The inert gas is high-purity argon.

The acid solution is a hydrochloric acid solution with the mass percentage concentration of 2%.

Example 3

A method for preparing polyaspartic acid potassium used for plant growth promoter, its concrete scheme is as follows:

adding 180g of L-aspartic acid and 10g of solid acid catalyst into a reaction kettle, controlling the temperature to 220 ℃, stirring for condensation reaction for 6 hours, then cooling to room temperature, filtering to remove the solid acid catalyst, then precipitating the reactant in pure water, filtering and drying to obtain polysuccinimide; adding 150g of polysuccinimide into a reaction kettle, adding 60g of potassium hydroxide solution with the mass percentage concentration of 20%, heating to 80 ℃ under the protection of inert gas, carrying out hydrolysis reaction for 60min, cooling to room temperature, adjusting the pH value to be neutral by using an acid solution, adding 30g of cyclic silicon-based chitosan and 5g of citric acid, stirring for 160min at 80 ℃, adding 500g of ethanol into the reaction kettle, precipitating, filtering, washing, drying and crushing to obtain the potassium polyaspartate for the plant growth promoter.

The solid acid catalyst is a metal hybrid solid acid catalyst with high acid loading capacity, and the preparation method comprises the following steps:

crushing 80g of dried plant material to 100 meshes, mixing with 240g of concentrated sulfuric acid, stirring at room temperature for reaction for 10 hours, heating the mixture to 180 ℃ after the reaction is completed, reacting for 14 hours, filtering after the reaction is completed, washing 10g of obtained solid, adding the washed solid into 80g of hybrid modified solution, uniformly mixing, adding the obtained solid into a high-pressure reaction kettle, controlling the temperature at 160 ℃, reacting for 20 hours, filtering after the reaction is completed, and calcining for 7 hours at 600 ℃ under the protection of nitrogen after the washing; after the preparation, the metal hybrid solid acid catalyst with high acid loading can be obtained.

The preparation method of the cyclosiloxane chitosan comprises the following steps:

step one, adding 30g of chitosan, 180g of tetrahydrofuran, 6g of 2-bromoisobutyryl bromide and 2.5g of trimethylamine into a reaction kettle, introducing nitrogen, controlling the temperature to be 60 ℃, stirring for reaction for 120min, filtering and drying to obtain a product 1;

step two, mixing 7g of 2,4, 6-tripropenyloxy-1, 3, 5-triazine, 3.4g of 1,3,5, 7-tetramethylcyclotetrasiloxane, 0.2g of tin octylate, 0.07g of chloroplatinic acid and 150g of DMF uniformly in a reaction kettle, heating to 74 ℃, and reacting for 5 hours to obtain a mixed product 2;

and step three, adding 34g of the product 1 into the mixed product 2, adding 7g of cuprous bromide, 2.5g of ammonium persulfate and 3.2g of cardanol, heating to 70 ℃, reacting for 20 hours, filtering, washing with methanol, and drying to obtain the cyclic silicon-based chitosan.

The hybridization modification solution contains 0.5mol/L of niobium citrate, 0.3mol/L of ferric nitrate and 0.8mol/L of phosphoric acid.

The plant material is poplar wood chips.

The water content of the plant material is 2.3%.

The inert gas is high-purity nitrogen.

The acid solution is a hydrochloric acid solution with the mass percentage concentration of 5%.

The results of the tests on the yield of potassium polyaspartate and the plant growth promoting effect of the potassium polyaspartate solution of the above examples are shown in the following table:

	yield (%)	Percentage of germination (%)
			Example 1	94.1	96.7
Example 2	95.3	98.2
			Example 3	96.7	99.6

Comparative example 1

A method for preparing polyaspartic acid potassium used for plant growth promoter, its concrete scheme is as follows:

adding 100g of L-aspartic acid and 0.5g of phosphoric acid catalyst into a reaction kettle, controlling the temperature to 180 ℃, stirring for condensation reaction for 2 hours, then cooling to room temperature, filtering to remove the phosphoric acid catalyst, then precipitating the reactant in pure water, filtering and drying to obtain polysuccinimide; and then adding 100g of polysuccinimide into a reaction kettle, adding 40g of potassium hydroxide solution with the mass percentage concentration of 10%, heating to 60 ℃ under the protection of inert gas, carrying out hydrolysis reaction for 20min, then cooling to room temperature, adjusting the pH value to be neutral by using acid solution, adding 300g of ethanol into the reaction kettle, precipitating, filtering, washing, drying and crushing to obtain the potassium polyaspartate for the plant growth promoter.

The inert gas is high-purity nitrogen.

The acid solution is a hydrochloric acid solution with the mass percentage concentration of 1%.

Comparative example 2

A method for preparing polyaspartic acid potassium used for plant growth promoter, its concrete scheme is as follows:

adding 100g of L-aspartic acid and 0.5g of solid acid catalyst into a reaction kettle, controlling the temperature to 180 ℃, stirring for condensation reaction for 2 hours, then cooling to room temperature, filtering to remove the solid acid catalyst, then precipitating the reactant in pure water, filtering and drying to obtain polysuccinimide; and then adding 100g of polysuccinimide into a reaction kettle, adding 40g of potassium hydroxide solution with the mass percentage concentration of 10%, heating to 60 ℃ under the protection of inert gas, carrying out hydrolysis reaction for 20min, then cooling to room temperature, adjusting the pH value to be neutral by using acid solution, adding 20g of chitosan and 2g of citric acid, stirring for 120min at the temperature of 60 ℃, adding 300g of ethanol into the reaction kettle, precipitating, filtering, washing, drying and crushing to obtain the polyaspartic acid potassium used for the plant growth promoter.

The solid acid catalyst is a metal hybrid solid acid catalyst with high acid loading capacity, and the preparation method comprises the following steps:

crushing 50g of dried plant material to 20 meshes, mixing with 150g of concentrated sulfuric acid, stirring at room temperature for 5 hours for reaction, heating the mixture to 140 ℃ after the reaction is finished, reacting for 8 hours, filtering after the reaction is finished, washing 5g of obtained solid, adding the washed solid into 50g of hybrid modified solution, uniformly mixing, adding the obtained solid into a high-pressure reaction kettle, controlling the temperature at 140 ℃ for reaction for 10 hours, filtering after the reaction is finished, and calcining at 300 ℃ for 3 hours under the protection of nitrogen after the washing is finished; after the preparation, the metal hybrid solid acid catalyst with high acid loading can be obtained.

The hybridization modification solution contains 0.1mol/L of niobium citrate, 0.05mol/L of ferric nitrate and 0.3mol/L of phosphoric acid.

The plant material is corncob.

The water content of the plant material is 3.2%.

The inert gas is high-purity nitrogen.

The acid solution is a hydrochloric acid solution with the mass percentage concentration of 1%.

Comparative example 3

A method for preparing polyaspartic acid potassium used for plant growth promoter, its concrete scheme is as follows:

adding 100g of L-aspartic acid and 0.5g of solid acid catalyst into a reaction kettle, controlling the temperature to 180 ℃, stirring for condensation reaction for 2 hours, then cooling to room temperature, filtering to remove the solid acid catalyst, then precipitating the reactant in pure water, filtering and drying to obtain polysuccinimide; and then adding 100g of polysuccinimide into a reaction kettle, adding 40g of potassium hydroxide solution with the mass percentage concentration of 10%, heating to 60 ℃ under the protection of inert gas, carrying out hydrolysis reaction for 20min, then cooling to room temperature, adjusting the pH value to be neutral by using acid solution, adding 20g of modified chitosan and 2g of citric acid, stirring for 120min at 60 ℃, adding 300g of ethanol into the reaction kettle, precipitating, filtering, washing, drying and crushing to obtain the polyaspartic acid potassium used for the plant growth promoter.

The preparation method of the modified chitosan comprises the following steps:

step one, adding 30g of chitosan, 180g of tetrahydrofuran, 6g of 2-bromoisobutyryl bromide and 2.5g of trimethylamine into a reaction kettle, introducing nitrogen, controlling the temperature to be 60 ℃, stirring for reaction for 120min, filtering a product, washing with methanol, and drying to obtain the modified chitosan.

Otherwise, the same procedure as in example 1 was repeated.

The results of the above comparative examples on the yield of potassium polyaspartate and the plant growth promoting effect of the potassium polyaspartate solution are shown in the following table:

	yield (%)	Percentage of germination (%)
			Comparative example 1	82.4	96.3
Comparative example 2	89.1	96.8
			Comparative example 3	92.7	98.5