CN111960904A

CN111960904A - Green nitrification inhibitor and preparation method and application thereof

Info

Publication number: CN111960904A
Application number: CN202010843612.2A
Authority: CN
Inventors: 高会
Original assignee: Qilu University of Technology
Current assignee: Shandong Unilever Biotechnology Co ltd
Priority date: 2020-08-20
Filing date: 2020-08-20
Publication date: 2020-11-20
Anticipated expiration: 2040-08-20
Also published as: CN111960904B

Abstract

The invention provides a green nitrification inhibitor and a preparation method and application thereof. The nitrification inhibitor is prepared by the following raw materials through reaction: 0.5-1.5 parts of composite initiator, 2-10 parts of pyrazole derivative, 5-15 parts of organic acid containing carbon-carbon double bond and 30-50 parts of solvent water. The preparation method is simple, efficient, pollution-free and low in cost, and extra inert protective gas is not needed to be injected in the industrial production process, so that potential risks in the industrial production process are reduced, and the cost is further reduced; the prepared nitrification inhibitor has good stability, less residue in agricultural products, less toxicity and less environmental pollution, can effectively reduce the leaching and denitrification loss of the nitrogen fertilizer, inhibit the conversion of ammonium nitrogen in the nitrogen fertilizer to nitrate nitrogen, improve the nitrogen utilization rate, and has the effects of dissolving phosphorus, preventing phosphorus from being fixed by soil and the like.

Description

Green nitrification inhibitor and preparation method and application thereof

Technical Field

The invention relates to a green nitrification inhibitor and a preparation method and application thereof, belonging to the technical field of agricultural fertilizers.

Background

With the continuous improvement of the economic level of China, the quality requirements of the food materials by the nation are more and more critical. In order to meet the high requirements of people on food materials in daily life, particularly on grains and vegetables, modern agricultural production focuses more on management from the seedling cultivation and growth stages of crops so as to improve the yield of the crops and reduce the enrichment of potential harmful substances to human bodies in the crops. At present, the method of applying ammonium nitrogen fertilizer and amide nitrogen fertilizer to crops is often adopted to improve the crop yield. However, research results show that only 30-60% of the applied ammonium nitrogen fertilizer and amide nitrogen fertilizer can be absorbed by crops, and the rest is lost in the forms of volatilization, leaching and denitrification; this not only causes waste of fertilizer, but also causes pollution to the environment. In view of the above, researchers at home and abroad make extensive studies on how to improve the utilization rate of nitrogen fertilizers, and develop various nitrification inhibitors to reduce the leaching and denitrification losses of nitrogen fertilizers, inhibit the conversion of ammonium nitrogen to nitrate nitrogen in nitrogen fertilizers, reduce the enrichment of potential harmful substances to human bodies in crops, and improve the utilization rate of nitrogen elements of the crops.

The nitrification inhibitors which are widely researched at present mainly comprise hundreds of types of pyridine, thiourea, acetylene, triazine, carbon disulfide and the like, but the nitrification inhibitors which are applied to the agricultural production mainly comprise three types of dicyandiamide, 2-chloro-6 (trichloromethyl) pyridine and 3, 4-dimethylpyrazole phosphate. The nitrification inhibitor dicyandiamide mainly inhibits the first reaction step of the soil nitrification process, namely NH₄ ⁺Is oxidized to NO₂ ^-And the nitrification inhibition effect can be better exerted in the soil with higher pH value in dry farmland. The nitrogen content of dicyandiamide is high (66%), and it can be slowly degraded into nitrogen fertilizer which can be used by crops, and the final degradation product is only CO₂、H₂O and NH₃And the dicyandiamide has no pollution to the natural environment, so that the dicyandiamide can be used as a slow release fertilizer or mixed with other fertilizers for use. However, dicyandiamide has good water fluidity and is easily reacted with NH₄ ⁺Separating, namely in heavy rainfall weather or soil with good water permeability, the dicyandiamide is easy to run off along with water, so that the nitrification inhibition effect is reduced; in addition, excessive or improper application of dicyandiamide can cause toxicity to crops and damage the quality of crops. 2-chloro-6 (trichloromethyl) pyridine serving as nitrification inhibitor can effectively slow down NH₄ ⁺To NO₂ ^-Thereby reducing the leaching loss of the nitrogen fertilizer and reducing NO₂ ^-And NO₃ ^-Pollution of surface water and groundwater. However, 2-chloro-6 (trichloromethyl) pyridine belongs to an organic chlorine-containing nitrification inhibitor, is easily dissolved in an organic solvent, is easily volatilized and is easily photolyzed, and can cause toxicity to soil, environment and crops when being applied in excess.

Compared with the two nitrification inhibitors, the 3, 4-dimethylpyrazole phosphate has the advantages of long inhibition effect time, small dosage, weak water migration capacity, less residue in agricultural products, small environmental pollution and the like, and is widely regarded and applied in actual agricultural production; however, the 3, 4-dimethylpyrazole phosphate has the defects of single function, still-improved nitrification inhibition effect, easy volatilization, no high temperature resistance and the like.

In summary, the present invention provides a method for preparing a nitrification inhibitor with multiple functions (not only can effectively reduce the leaching and denitrification loss of the nitrogenous fertilizer, inhibit the conversion of ammonium nitrogen in the nitrogenous fertilizer to nitrate nitrogen, and has multiple functions of phosphate solubilization, phosphorus fixation prevention by soil, etc.), less residue in agricultural products, less toxicity, less environmental pollution, high temperature resistance and stability.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a green nitrification inhibitor and a preparation method thereof. The preparation method is simple, efficient, pollution-free and low in cost, and extra inert protective gas is not needed to be injected in the industrial production process, so that potential risks in the industrial production process are reduced, and the cost is further reduced; the prepared nitrification inhibitor has good stability, less residue in agricultural products, less toxicity and less environmental pollution, can effectively reduce the leaching and denitrification loss of the nitrogen fertilizer, inhibit the conversion of ammonium nitrogen in the nitrogen fertilizer to nitrate nitrogen, improve the nitrogen utilization rate, and has the effects of dissolving phosphorus, preventing phosphorus from being fixed by soil and the like.

The invention also provides application of the green nitrification inhibitor.

The technical scheme of the invention is as follows:

the green nitrification inhibitor is characterized by being prepared by reacting the following raw materials:

0.5-1.5 parts of composite initiator, 2-10 parts of pyrazole derivative, 5-15 parts of organic acid containing carbon-carbon double bond and 30-50 parts of solvent water.

According to the invention, the nitrification inhibitor is prepared by reacting the following raw materials:

1 part of composite initiator, 3-5 parts of pyrazole derivative, 6-8 parts of organic acid containing carbon-carbon double bonds and 33-40 parts of solvent water.

According to the invention, the composite initiator is preferably one or a mixture of more than two of cumene hydroperoxide/sodium persulfate/potassium carbonate, azobisisobutyronitrile/benzoyl peroxide/sodium carbonate or ammonium persulfate/ammonium bicarbonate/tert-butyl peroxybenzoate.

According to the present invention, the pyrazole derivative is preferably one or a combination of two or more of 3, 4-dimethylpyrazole, 4-chloro-3-methylpyrazole, N-hydroxymethyl-3, 4-dimethylpyrazole, and N-hydroxymethyl-4-chloro-3-methylpyrazole.

According to the present invention, the organic acid having a carbon-carbon double bond is preferably one or a combination of two or more of acrylic acid, methacrylic acid, ethacrylic acid, fumaric acid (fumaric acid), citraconic acid (cis-methylbutenedioic acid), itaconic acid (itaconic acid), crotonic acid (crotonic acid), cinnamic acid (β -phenylacrylic acid), and maleic acid (maleic acid).

According to the invention, the number average molecular weight of the nitrification inhibitor is 2000-10000, and the mass content of the pyrazole derivative is 5-10%.

The preparation method of the green nitrification inhibitor comprises the following steps:

in solvent water, under the action of a compound initiator, organic acid containing carbon-carbon double bonds and pyrazole derivatives are subjected to polymerization reaction to prepare the nitrification inhibitor.

According to the invention, the polymerization reaction temperature is preferably 40-100 ℃, the polymerization reaction time is 1-6 h, and the heating rate is preferably 1-5 ℃/min; preferably, the polymerization reaction temperature is 40-80 ℃.

According to the invention, the preparation method of the green nitrification inhibitor comprises the following steps:

heating solvent water to 40-100 ℃, adding organic acid containing carbon-carbon double bonds and pyrazole derivatives, fully and uniformly dispersing, slowly adding a composite initiator, and reacting at 40-100 ℃ for 1-6 hours to obtain the nitrification inhibitor.

The green nitrification inhibitor is used as a nitrification inhibitor to be used independently or applied to fertilizers.

The invention has the following technical characteristics and beneficial effects:

1. the preparation process is simple, efficient, pollution-free and low in cost; according to the invention, the composite initiator is added into a chemical synthesis system of the organic acid containing carbon-carbon double bonds and the pyrazole derivative to improve the initiation efficiency, and the composite initiator performs a chemical reaction to generate protective gas to provide an oxygen-free environment, so that an additional inert protective gas is not required to be introduced, the danger caused by introducing a large amount of inert protective gas in the large-scale industrial production process is avoided, and the cost is further reduced.

2. According to the invention, a viscous liquid organic acid polymer nitrification inhibitor product with the number average molecular weight of 2000-10000 and the pyrazole derivative mass content of 5-10% is chemically synthesized, the types of nitrification inhibitors and the varieties of nitrification inhibitors applicable to industrial production are broadened, the quality and the yield of crops are improved, and the defects of high volatility, residue in agricultural products, environmental pollution and the like of the existing nitrification inhibitors are reduced. The prepared nitrification inhibitor has good stability, small volatility and long storage time (the storage time is up to 12 months under the conditions of 30 ℃ of temperature, 40 percent of relative humidity and shading condition); good water solubility and small dosage (0.952L/m)³The dosage of the fertilizer can achieve excellent phosphate solubilizing effect, and the nitrogen utilization rate can be effectively improved by 0.5 wt% of the dosage of the fertilizer); less residue in agricultural products, less toxicity and less environmental pollution.

3. The nitration inhibitor of the invention chemically introduces pyrazole derivatives on the structural unit of the poly organic acid, and has great advantages compared with simple physical mixing. Compared with simple physical mixing of the poly organic acid and the pyrazole derivative, the prepared nitrification inhibitor has the advantages of good stability, small volatility, high temperature resistance, capability of effectively reducing the leaching and denitrification loss of the nitrogen fertilizer, inhibiting the conversion of ammonium nitrogen to nitrate nitrogen in the nitrogen fertilizer, improving the nitrogen utilization rate and the like, has the effects of dissolving phosphorus and preventing the phosphorus from being fixed by soil, and has multiple effects of increasing the air permeability of the soil and the like; in addition, the effect of the nitrification inhibitor of the invention is better than that of the conventional nitrification inhibitor product with single function, such as 3, 4-dimethylpyrazole phosphate.

4. The nitrification inhibitor prepared by the invention can be used in the preparation process of water-soluble fertilizers, liquid fertilizers, compound fertilizers and other fertilizers, and further improves the comprehensive performance of the fertilizers.

Drawings

FIG. 1 is an external view of a nitrification inhibitor prepared in example 1 of the present invention;

FIG. 2 is a graph comparing nitrification inhibitors prepared in example 1 of the present invention before (a) and after (b) phosphate solubilization;

FIG. 3 is a graph showing the application of the nitrification inhibitor prepared in example 1 of the present invention to the improvement of nitrogen utilization.

Detailed Description

The present invention will be further described with reference to the following examples, but is not limited thereto.

Meanwhile, the experimental methods described in the following examples are all conventional methods unless otherwise specified; the reagents and materials are commercially available, unless otherwise specified.

Example 1

A preparation method of a green nitrification inhibitor comprises the following steps:

the method comprises the following steps: adding 200g of distilled water into a reaction kettle with a temperature sensor and a stirrer, and heating the reaction kettle from room temperature to 40 ℃ at the heating rate of 1 ℃/min;

step two: under the condition of stirring, sequentially adding 40g of methacrylic acid and 20g of 3, 4-dimethylpyrazole monomer into the system in the step (I), and stirring until the monomer is completely dispersed;

step three: slowly adding 6g of compound initiator (azodiisobutyronitrile/benzoyl peroxide/sodium carbonate, the molar ratio of the azodiisobutyronitrile to the benzoyl peroxide to the sodium carbonate is 1:1:1) into the system in the step (II); then stirring and reacting for 2h at 40 ℃, and finally cooling and collecting the product. The reaction does not need to be additionally filled with inert gas.

The nitrification inhibitor obtained in the present example has a number average molecular weight of 6000 as measured by a gel permeation chromatograph test.

The appearance of the product prepared in this example is shown in fig. 1, indicating that the product is a viscous liquid.

Example 2

A method for preparing a green nitrification inhibitor, as described in example 1, except that, in the first step, the temperature rise rate is 3 ℃/min, and the temperature rise temperature is 80 ℃; the other steps were the same as in example 1.

Example 3

A method for preparing a green nitrification inhibitor, as described in example 1, except that the mass of the compound hair agent, 3, 4-dimethylpyrazole, methacrylic acid and distilled water used are 8g, 40g, 64g and 320g, respectively; the other steps were the same as in example 1.

Example 4

A method for preparing a green nitrification inhibitor, which is as described in example 1, except that the organic acid monomer used in the second step is itaconic acid, and the addition amount and other steps are the same as those of example 1.

Example 5

A green nitrification inhibitor was prepared as described in example 1, except that the pyrazole derivative monomer used in step two was 4-chloro-3-methylpyrazole, and the amounts added and other steps were the same as those in example 1.

Example 6

A process for the preparation of a green nitrification inhibitor, as described in example 1, except that the reaction time in step three is 6 hours, and the other steps are the same as in example 1.

Comparative example 1

A preparation method of a nitrification inhibitor comprises the following steps:

step two: adding 40g of methacrylic acid monomer into the system in the step (I) under the condition of stirring, and stirring until the monomer is completely dispersed;

step three: adding 6g of composite initiator (azodiisobutyronitrile/benzoyl peroxide/sodium carbonate, wherein the molar ratio of the azodiisobutyronitrile to the benzoyl peroxide to the sodium carbonate is 1:1:1) into the system in the step (II); then stirring and reacting for 2h at 40 ℃, and finally cooling and collecting the product. The reaction does not need to be additionally filled with inert gas.

Step four: and (3) directly mixing the product collected in the step (three) with 20g of 3, 4-dimethylpyrazole monomer, and stirring for 2h at 40 ℃ to obtain the final product.

Comparative example 2

A nitrification inhibitor was prepared as described in example 1, except that the composite initiator used in step three was replaced with 6g of ammonium persulfate, and the other steps were carried out under the same conditions as in example 1.

In the comparative example, the initiator used is not used to initiate the reaction because the protective gas is not used, and the target product is not obtained finally.

Comparative example 3

A nitrification inhibitor was prepared as described in example 1, except that the composite initiator used in step three was replaced with 6g of sodium persulfate, and the other steps were carried out under the same conditions as in example 1.

Comparative example 4

A nitrification inhibitor was prepared as described in example 1, except that the composite initiator used in step three was replaced with 6g of benzoyl peroxide, and the other steps were carried out under the same conditions as in example 1.

Comparative example 5

A nitrification inhibitor was prepared as described in example 1, except that the composite initiator used in step III was replaced with 6g of azobisisobutyronitrile, and the other steps were carried out under the same conditions as in example 1.

Test example 1

1. Phosphorus dissolution test

Test samples: examples 1 to 6, comparative examples 1 to 2, and 3, 4-dimethylpyrazole phosphate commercially available.

The test method comprises the following steps:

respectively adding the test sample into turbid solutions of calcium nitrate and orthophosphate (the mass concentration of calcium nitrate in the turbid solution is 0.05g/mL, the mass concentration of orthophosphate is 0.02g/mL, and the addition amount of the test sample is 0.952L/m³) And observing the change condition of the solution. (the excellent phosphorus-dissolving effect means that the solution becomes clear from turbidity and the precipitate disappears completely; the good phosphorus-dissolving effect means that the precipitate disappears partially; and the no phosphorus-dissolving effect means that the turbid solution does not change)

2. Nitrogen utilization rate related test

Test samples: examples 1 to 6, nitrification inhibitors prepared in comparative examples 1 to 2, and commercially available 3, 4-dimethylpyrazole phosphate.

The test method comprises the following steps: test samples (0.5% of the mass of urea, namely 0.015g) were added to the same mass (70g) of soil from the same source containing urea (3g), respectively, and then water of the same mass (15g) was added, respectively, and left under a closed condition (40 ℃) for 24 hours, and the change of the ammonia volatilization tube was observed. While a blank experiment was set up, i.e. without addition of test sample, other conditions and methods were as described above.

The comparison graph of the nitrification inhibitor prepared in the embodiment 1 of the invention before and after phosphate solubilization is shown in fig. 2, and the turbid solution is changed from a turbid state to a clear state, so that the nitrification inhibitor has a good phosphate solubilization effect.

Referring to fig. 3, the comparison between the nitrification inhibitor prepared in example 1 of the present invention and ammonia volatilization conditions in the blank experiment shows that: after the ammonia is placed in the same environment for 24 hours, the ammonia volatilization amount of the embodiment 1 far exceeds the maximum range of the ammonia volatilization tube used in the experiment, so that the ammonia volatilization amount is more than 3mg/m³The method is far higher than a blank experiment, which shows that the addition of the nitrification inhibitor prepared in example 1 inhibits the conversion of ammonium nitrogen into nitrate nitrogen and improves the utilization rate of nitrogen elements; the ammonium nitrogen is released in the form of ammonia gas, and the side proves that the addition of the nitrification inhibitor of the invention effectively slows downAnd the content of ammonium nitrogen in the system is reduced.

The nitrification inhibitors prepared in examples 1 to 6 and comparative examples 1 to 2 and the commercially available 3, 4-dimethylpyrazole phosphate exhibited the phosphorus solubilizing effect and ammonia volatilization, and the test results are shown in table 1.

TABLE 1 phosphorus-solubilizing Effect and Ammonia volatilization amount

As can be seen from the test results in Table 1, the product of the poly organic acid nitrification inhibitor obtained by the method of the invention has the advantages of small dosage, excellent phosphate solubilizing effect and high efficiency in improving the utilization rate of nitrogen element. The ammonia volatilization amount of the nitrification inhibitor obtained in the embodiment of the invention is far beyond the maximum range of the ammonia volatilization tube in the experiment, so that the ammonia volatilization amount is more than 3mg/m³(ii) a The nitrification inhibitor prepared by simply and physically mixing the organic acid and the pyrazole derivative, simply adding the 3, 4-dimethylpyrazole phosphate and not adding the composite initiator has no phosphorus-dissolving effect, and the ammonia volatilization amount is less than that of the nitrification inhibitor.

Claims

1. The green nitrification inhibitor is characterized by being prepared by reacting the following raw materials:

2. The green nitrification inhibitor according to claim 1, wherein the nitrification inhibitor is prepared by reacting the following raw materials:

3. The green nitrification inhibitor according to claim 1, wherein the complex initiator is one or a mixture of two or more of cumene hydroperoxide/sodium persulfate/potassium carbonate, azobisisobutyronitrile/benzoyl peroxide/sodium carbonate or ammonium persulfate/ammonium bicarbonate/tert-butyl peroxybenzoate.

4. The green nitrification inhibitor according to claim 1, wherein the pyrazole derivative is one or a combination of two or more of 3, 4-dimethylpyrazole, 4-chloro-3-methylpyrazole, N-hydroxymethyl-3, 4-dimethylpyrazole, and N-hydroxymethyl-4-chloro-3-methylpyrazole.

5. The green nitrification inhibitor according to claim 1, wherein the organic acid having a carbon-carbon double bond is one or a combination of two or more of acrylic acid, methacrylic acid, ethacrylic acid, fumaric acid, cis-methylbutenedioic acid, itaconic acid, crotonic acid, β -phenylacrylic acid, and maleic acid.

6. The green nitrification inhibitor according to claim 1, wherein the nitrification inhibitor has a number average molecular weight of 2000 to 10000 and a mass content of the pyrazole derivative is 5 to 10%.

7. A process for the preparation of a green nitrification inhibitor according to any one of claims 1 to 6, comprising the steps of:

8. The preparation method of the green nitrification inhibitor according to claim 7, wherein the polymerization reaction temperature is 40-100 ℃, the polymerization reaction time is 1-6 h, and the temperature rise rate is 1-5 ℃/min; preferably, the polymerization reaction temperature is 40-80 ℃.

9. The method for preparing a green nitrification inhibitor according to claim 7, wherein the method for preparing a green nitrification inhibitor comprises the steps of:

10. The use of a green nitrification inhibitor according to any one of claims 1 to 6, as a nitrification inhibitor, alone or in a fertilizer.