Application of high-activity urease inhibitor in urea and compound fertilizer
By combining dihydroxybenzoic acid compounds with the nitrification inhibitor DMPP, the problem of instability of urease inhibitors in acidic environments was solved, achieving efficient and stable urea nitrogen conversion management, improving nitrogen fertilizer utilization and inhibition effect, and reducing ammonia volatilization and nitrification losses.
Patent Information
- Application Number
- CN202511438987.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-10
- Publication Date
- 2025-12-16
AI Technical Summary
Existing urease inhibitors, such as NBPT, are unstable in acidic environments and at high temperatures, resulting in low urea utilization, severe ammonia volatilization and nitrification-denitrification losses, and a lack of acid-resistant and stable urease inhibitors combined with nitrification inhibitors.
Dihydroxybenzoic acid compounds such as 2,3-dihydroxybenzoic acid, 2,5-dihydroxybenzoic acid, and 3,4-dihydroxybenzoic acid are used as single- or dual-effect inhibitors, which are combined with nitrification inhibitor DMPP to form a stable dual-effect inhibitor system. This system is then applied to urea and compound fertilizers through spraying, blending, or melt addition.
It significantly improves urea nitrogen utilization, reduces ammonia volatilization and nitrification-denitrification losses, increases nitrogen fertilizer utilization by 50-60%, has an inhibition effect of 50-90%, has better stability than NBPT, is environmentally friendly, and has low cost.
Smart Images
Figure CN121135546A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of agricultural chemistry and fertilizer technology, specifically involving several novel urease inhibitors, dual-effect inhibitors, and combinations of inhibitors with nutrients, as well as their application in urea-based fertilizers. They are mainly used to inhibit soil urease activity, reduce ammonia volatilization, improve urea nitrogen utilization, and are combined with nitrification inhibitors to form stable and highly efficient dual-effect inhibitors. Background Technology
[0002] Urea is the most widely used nitrogen fertilizer globally, but its utilization rate is generally low, typically only 30-70%. The main reasons for this problem are: A) Ammonia volatilization loss: After urea is applied to the soil, it rapidly hydrolyzes under the action of soil urease to produce ammonium carbonate, leading to an increase in soil pH and subsequently causing a large amount of NH3 volatilization loss. This not only causes nitrogen loss but also leads to environmental pollution (precursors to PM2.5) and ecological problems. B) Nitrification-denitrification loss: Ammonium nitrogen (NH4+) produced after urea hydrolysis... + ) is converted into nitrate nitrogen (NO3) by nitrifying bacteria. - The latter is easily lost through leaching or further through denitrification as nitrogen (N2).
[0003] To address the aforementioned issues, adding urease inhibitors (UI) and nitrification inhibitors (NI) is a recognized effective approach. Existing commercial urease inhibitors include N-butylthiophosphoric triamine (NBPT), but they have several drawbacks, such as sensitivity to water, acid, and heat. When added during fertilizer production, they are easily deactivated by acidic nitrification inhibitors and acidic fertilizers, and the high temperatures encountered during production can severely compromise their stability. Novel urease inhibitors (UI) for use in acidic compound fertilizers, and novel urease inhibitors (UI) that are stable when combined with acidic nitrification inhibitors (NI), are currently lacking in the industry. Research in this area is severely insufficient, and mature, industrially viable technical solutions have not yet been developed.
[0004] Therefore, developing novel, acid-resistant, stable, and environmentally friendly urease inhibitors and solving their stable application in fertilizer products has significant economic and social value. Summary of the Invention
[0005] To address the aforementioned technical problems, this invention provides a novel urease inhibitor that is highly efficient, environmentally friendly, low-cost, and acid-resistant.
[0006] This invention provides the application of urease inhibitors (UI) in urea and compound fertilizers, wherein the urease inhibitors include single-effect urease inhibitors or dual-effect inhibitors.
[0007] Furthermore, in the above technical solution, the single-effect urease inhibitor is selected from dihydroxybenzoic acid, dihydroxybenzaldehyde, dihydroxyacetophenone, dihydroxynaphthalene, or substituted dihydroxybenzene compounds.
[0008] Under preferred conditions, the single-acting urease inhibitor is selected from one or more of 2,3-dihydroxybenzoic acid (2,3-DHBA), 2,5-dihydroxybenzoic acid (2,5-DHBA), 3,4-dihydroxybenzoic acid (protocatechuic acid, PCA), 2,3-dihydroxybenzaldehyde, 4-bromocatechol, tert-butylhydroquinone, 2,5-dihydroxyacetophenone, and 2,7-dihydroxynaphthalene.
[0009] Furthermore, in the above technical solution, under the most preferred conditions, the single-effect urease inhibitor is selected from 2,3-dihydroxybenzoic acid (2,3-DHBA), 2,5-dihydroxybenzoic acid (2,5-DHBA), and 3,4-dihydroxybenzoic acid (protocatechuic acid, PCA).
[0010] Studies have found that adding urease inhibitors at 0.16% (nitrogen content) to urea or compound fertilizer has an inhibitory effect comparable to or better than that of adding NBPT at 0.04%.
[0011] Furthermore, in the above technical solution, the dual-effect inhibitor (also known as dual-effect fertilizer synergist) includes a single-effect urease inhibitor and a nitrification inhibitor (NI).
[0012] Furthermore, in the above technical solution, the single-effect urease inhibitor is selected from one or more of 2,3-dihydroxybenzoic acid (2,3-DHBA), 2,5-dihydroxybenzoic acid (2,5-DHBA), 3,4-dihydroxybenzoic acid (protocatechuic acid, PCA), 2,3-dihydroxybenzaldehyde, 4-bromocatechol, tert-butylhydroquinone, 2,5-dihydroxyacetophenone, and 2,7-dihydroxynaphthalene.
[0013] Furthermore, in the above technical solution, the single-effect urease inhibitor is preferably selected from 2,3-dihydroxybenzoic acid (2,3-DHBA), 2,5-dihydroxybenzoic acid (2,5-DHBA), or 3,4-dihydroxybenzoic acid (protocatechuic acid, PCA).
[0014] Furthermore, in the above technical solution, the nitration inhibitor is selected from at least one of 3,4-dimethylpyrazole phosphate (DMPP) and 3,4-dimethylpyrazole succinate (DMPSA).
[0015] Furthermore, in the above technical solution, the dual-effect inhibitor also includes a solvent and a stabilizer system.
[0016] Furthermore, in the above technical solution, the solvent is selected from one or more of water, methanol, ethanol, N-methylpyrrolidone (NMP), dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), N,N-dimethylacetamide, ethylene glycol monomethyl ether, ethylene glycol, and diethylene glycol.
[0017] Furthermore, in the above technical solution, the weight of the single-effect urease inhibitor, nitration inhibitor, and solvent is as follows: urease inhibitor: 0.1-12 parts; nitration inhibitor: 0.1-15 parts; solvent: 50-80 parts.
[0018] Furthermore, in the above technical solution, the application method of the urease inhibitor includes, but is not limited to:
[0019] Spraying: After urea granulation, the synergist solution is evenly sprayed onto the surface of the urea granules during cooling or drum rotation.
[0020] Blending: Directly and physically blending liquid or solid synergists with granular urea;
[0021] Melt addition: Before granulation of molten urea, the synergist is added to the molten urea, and after thorough mixing, granulation is performed.
[0022] Fertilizer and water integration: In a small container, the liquid or solid form inhibitor is fully diluted and mixed with a small amount of water or fertilizer stock solution, and then poured into a large fertilizer tank and stirred again to ensure even mixing.
[0023] Furthermore, in the above technical solution, in the method of applying the urease inhibitor, the effective amount of the urease inhibitor added is 0.01% to 0.16% of the weight of urea; the effective amount of the nitration inhibitor added is 0.05% to 0.09% of the weight of urea.
[0024] Extensive experimental studies have revealed that the first three specific dihydroxybenzoic acid isomers all exhibit significant urease inhibitory effects and environmental adaptability. They can all effectively occupy the active site of urease, inhibiting its catalytic activity.
[0025] Application advantages: They can all be used alone, providing flexibility in formulation development. For example, in cost-priority strategies, a single component with moderate inhibition but lower cost can be selected; in pH-sensitive applications, a single component with a more suitable dissociation constant can be selected to optimize performance.
[0026] The present invention also provides a stable compound formulation of the above-mentioned urease inhibitor and nitrification inhibitor, which solves the problems of poor compatibility and decomposition failure that may exist between the two in the fertilizer system, and realizes the synergistic regulation of the entire nitrogen conversion process (urease inhibition + nitrification inhibition).
[0027] The present invention also provides urea containing the above-mentioned synergist and urea-based fertilizers and their preparation methods, enabling industrial production and application.
[0028] Beneficial effects of the invention
[0029] 1. High efficiency: 2,3-DHBA, 2,5-DHBA, PCA, 2,3-dihydroxybenzaldehyde, 4-bromocatechol, tert-butylhydroquinone, 2,5-dihydroxyacetophenone, or 2,7-dihydroxynaphthalene all exhibit excellent urease inhibition effects, with ammonia volatilization inhibition rates reaching 50-90%. The residual period of urea in the soil can be extended by 7-10 days, providing a longer window for crop nitrogen absorption.
[0030] 2. Environmental protection and safety: The selected dihydroxybenzoic acid compounds are naturally occurring, have good environmental compatibility, are easily biodegradable, have no risk of toxic residues, and will not cause environmental concerns.
[0031] 3. Outstanding stability: This invention successfully solves the compatibility problem between NBPT (n-butylthiophosphoric triamine) and commonly used nitrification inhibitors (especially DMPP) in compounding and fertilizer storage, ensuring that the activity of the synergist does not significantly decrease during the shelf life of the fertilizer product (usually more than 6 months).
[0032] 4. Synergistic nitrogen management: The "UI+NI" composite mode achieves "dual control" of the urea nitrogen conversion pathway (delaying both hydrolysis and nitrification), simultaneously reducing ammonia volatilization and nitrification-denitrification losses, which can increase nitrogen fertilizer utilization rate by 50-60 percentage points.
[0033] 5. Cost advantage: The raw materials are relatively widely available and the synthesis process is mature. Compared with NBPT (n-butylthiophosphoric triamine), it has a potential cost advantage and is easy to promote. Attached Figure Description
[0034] Figure 1 A comparison of the stability of urease inhibitors and DMPP stored at 40°C;
[0035] Figure 2 Comparative diagram of the stability experiment of urease inhibitor and 15-15-15 compound fertilizer stored at 40℃. Detailed Implementation
[0036] The present invention will be further illustrated by the following examples, but the present invention is not limited thereto.
[0037] Example 1: Urea Residual Difference Rate
[0038] The national standard urea residue difference rate was determined according to GB / T 35113-2017 for n-butylthiophosphoric triamine (NBPT) and the compounds of this invention, including 2,3-DHBA, 2,5-DHBA, PCA, 2,3-dihydroxybenzaldehyde, 4-bromocatechol, tert-butylhydroquinone, 2,5-dihydroxyacetophenone, and 2,7-dihydroxynaphthalene.
[0039] Evaluation indicator: The more urea residue, the stronger the inhibition ability.
[0040] Table 1: Difference rate of urea residues for single urease inhibitors
[0041]
[0042]
[0043] Expected results: The inhibitory effects of 2,3-DHBA, 2,5-DHBA, PCA, 2,3-dihydroxybenzaldehyde, 4-bromocatechol, tert-butylhydroquinone, 2,5-dihydroxyacetophenone, and 2,7-dihydroxynaphthalene are all on the same order of magnitude as NBPT. They are all highly effective and independent urease inhibitors, rather than just "effective".
[0044] Example 2: Inhibition effect of soil-cultivated ammonia volatilization
[0045] The n-butylthiophosphoric triamine (NBPT) and the compounds of the present invention, namely 2,3-DHBA, 2,5-DHBA, PCA, 2,3-dihydroxybenzaldehyde, 4-bromocatechol, tert-butylhydroquinone, 2,5-dihydroxyacetophenone, and 2,7-dihydroxynaphthalene, are sprayed onto urea.
[0046] NBPT was added at 0.04% nitrogen content by mass, while 2,3-DHBA, 2,5-DHBA, and PCA were added at 0.16% nitrogen content by mass. Ammonia volatilization tests were conducted, and soil incubation tests were performed at 60% of field maximum water holding capacity and 0.2 g N / kg soil.
[0047] Table 2: Cumulative ammonia volatilization inhibition rate of a single urease inhibitor over 14 days
[0048]
[0049]
[0050] Example 3 Field Application Effect
[0051] A field experiment was conducted on irrigated desert soil in Zhangye, Gansu Province, involving the application of urea in combination with n-butylthiophosphoric triamine (NBPT) and the compounds of this invention, namely 2,3-DHBA, 2,5-DHBA, PCA, 2,3-dihydroxybenzaldehyde, 4-bromocatechol, tert-butylhydroquinone, 2,5-dihydroxyacetophenone, and 2,7-dihydroxynaphthalene. NBPT was added at a nitrogen content of 0.04% by mass, while 2,3-DHBA, 2,5-DHBA, PCA, 2,3-dihydroxybenzaldehyde, 4-bromocatechol, tert-butylhydroquinone, 2,5-dihydroxyacetophenone, and 2,7-dihydroxynaphthalene were added at a nitrogen content of 0.16% by mass.
[0052] Topdressing was applied during the corn's tasseling stage, and fresh samples were taken on the 3rd, 7th, 14th, and 28th days after topdressing to measure soil amide nitrogen, ammonium nitrogen, ammonia, etc. Finally, yield was measured and indicators such as ear length, tip length, and 100-grain weight were collected.
[0053] Table 3: Field nitrogen changes with a single urease inhibitor
[0054]
[0055]
[0056]
[0057] Table 4: Field agronomic performance of single urease inhibitors
[0058]
[0059] Example 6: Formulation stability test of UI / NI composite synergist
[0060] Test formulation:
[0061] Formula A: UI (12 parts) + DMPP (17 parts) + DMSO / water (73 parts)
[0062] Reference formula B: NBPT (4 parts) + DMPP (20 parts) + DMSO / water (76 parts).
[0063] Method: Each formulation synergist was placed under accelerated aging conditions (e.g., stored in a 40℃ constant temperature chamber for 28 days, simulating approximately 6 months of room temperature storage), and samples were taken at 0 days, 7 days, 14 days, and 28 days.
[0064] Evaluation indicators
[0065] Chemical stability: The residual content of the active ingredient in UI was determined by high performance liquid chromatography (HPLC).
[0066] Expected result: No significant decrease in UI content. This demonstrates the stability of the inhibitor of this invention.
[0067] Example 7: UI Acidic Environment Stability Test
[0068] The urease inhibitor of the present invention was mixed with DMPP and 15-15-15 and stored separately.
[0069] Method: Each powder was stored under accelerated aging conditions (e.g., stored in a 40℃ constant temperature oven for 28 days, simulating approximately 6 months of room temperature storage), and samples were taken at 0 days, 7 days, 14 days, and 28 days.
[0070] Evaluation indicators
[0071] Chemical stability: The residual content of the active ingredient in UI or NI was determined by high performance liquid chromatography (HPLC).
[0072] Expected result: No significant decrease in UI content. This demonstrates the stability of the inhibitor of this invention.
[0073] Example 8: Production and Application of Enhanced Urea Fertilizer (Field Trial)
[0074] Production: An internal addition or external spraying process is used. After diluting formulation A in Example 2, it is uniformly sprayed onto urea granules through a spray system during the cooling process of the urea drum, producing enhanced urea containing UI (0.16%) and DMPP (0.5%).
[0075] Field trial: Three treatments were set up with a total nitrogen input of 30 kg / mu: conventional urea, NBPT+DMPP urea (commercially available product), and the enhanced urea of this invention. Crop yield, nitrogen fertilizer partial productivity (PFPN), and ammonia volatilization flux were measured (real-time monitoring was performed using a dynamic chamber method).
[0076] Table 5: Field agronomic performance of stable type 3 compound fertilizer
[0077]
[0078] Expected results: Compared with conventional urea, the enhanced urea treatment of this invention reduces the peak ammonia volatilization by more than 60%, significantly increases grain yield and PFPN, and its effect is comparable to or better than commercially available NBPT+DMPP products.
[0079] Example 9: Production and Application of Enhanced Compound Fertilizers (Field Trial)
[0080] Production: A spraying process is used. After diluting formulation A in Example 2, it is uniformly sprayed onto urea granules through a spray system during the cooling process of the urea drum, producing enhanced urea containing UI (0.16%) and DMPP (0.5%).
[0081] Field trial: Three treatments were set up with a total nitrogen input of 30 kg / mu: conventional urea, NBPT+DMPP urea (commercially available product), and the enhanced urea of this invention. Crop yield, nitrogen fertilizer partial productivity (PFPN), and ammonia volatilization flux were measured (real-time monitoring was performed using a dynamic chamber method).
[0082] Table 6: Field agronomic performance of stable type 3 urea
[0083]
[0084] Expected results: Compared with conventional urea, the enhanced urea treatment of this invention reduces the peak ammonia volatilization by more than 60%, significantly increases grain yield and PFPN, and its effect is comparable to or better than commercially available NBPT+DMPP products.
[0085] Example 10: Detection of Residual Difference Rate of Type 3 Stable Fertilizer Urea
[0086] The national standard for urea residue difference rate was determined by testing the urea residue difference rate of urea containing n-butylthiophosphoric triamine (NBPT) and the dual-effect urea encapsulated in Example 8, in accordance with GB / T 35113-2017.
[0087] Table 7: Difference rate of residual stability type 3 urea
[0088]
[0089]
[0090] Expected results: The difference in urea residue rate is not significantly different from that of urea using NBPT alone.
[0091] Example 11: Detection of Nitrification Inhibition Rate of Type 3 Stable Fertilizer
[0092] The nitrification inhibition rate was tested according to GB / T 35113-2017 for urea containing DMPP and the dual-effect urea packaged in Example 8.
[0093] Table 8: Stability Type 3 Nitrification Inhibition Rate
[0094]
[0095] Expected result: The nitrification inhibition rate is greater than that of stable urea using DMPP alone.
[0096] The above embodiments describe the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the present invention. Various changes and modifications can be made to the present invention without departing from its principles, and all such changes and modifications fall within the scope of protection of the present invention.
Claims
1. The application of urease inhibitors in urea and compound fertilizers, characterized by: The urease inhibitor is selected from either a single-effect urease inhibitor or a dual-effect inhibitor.
2. The application of the urease inhibitor according to claim 1 in urea and compound fertilizer, characterized in that: The single-effect urease inhibitor is selected from dihydroxybenzoic acid, dihydroxybenzaldehyde, dihydroxyacetophenone, dihydroxynaphthalene, or substituted dihydroxybenzene compounds.
3. The application of the urease inhibitor according to claim 2 in urea and compound fertilizer, characterized in that: The single-effect urease inhibitor is selected from one or more of 2,3-dihydroxybenzoic acid, 2,5-dihydroxybenzoic acid, 3,4-dihydroxybenzoic acid, 2,3-dihydroxybenzaldehyde, 4-bromocatechol, tert-butylhydroquinone, 2,5-dihydroxyacetophenone, and 2,7-dihydroxynaphthalene.
4. The application of the urease inhibitor according to any one of claims 1-3 in urea and compound fertilizer, characterized in that: The dual-effect inhibitors include a single-effect urease inhibitor and a nitration inhibitor.
5. The application of the urease inhibitor according to claim 4 in urea and compound fertilizer, characterized in that: The nitration inhibitor is selected from at least one of 3,4-dimethylpyrazole phosphate and 3,4-dimethylpyrazole succinate.
6. The application of the urease inhibitor according to claim 4 in urea and compound fertilizer, characterized in that: The dual-effect inhibitor also includes a solvent and stabilizer system.
7. The application of the urease inhibitor according to claim 6 in urea and compound fertilizer, characterized in that: The solvent is selected from one or more of water, methanol, ethanol, N-methylpyrrolidone, dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, ethylene glycol monomethyl ether, ethylene glycol, and diethylene glycol.
8. The application of the urease inhibitor according to claim 6 in urea and compound fertilizer, characterized in that: The weights of the single-effect urease inhibitor, nitration inhibitor, and solvent are as follows: urease inhibitor: 0.1–12 parts; nitration inhibitor: 0.1–15 parts; solvent: 50–80 parts.
9. The application of the urease inhibitor according to claim 1 in urea and compound fertilizer, characterized in that, The application method of the urease inhibitor includes, but is not limited to: spraying: after urea granulation, the synergist solution is uniformly sprayed onto the surface of the urea granules during cooling or drum rotation. Blending: Physically blending liquid or solid synergists directly with granular urea; Melt addition: Adding synergists to molten urea before granulation, mixing thoroughly, and then granulating; Fertilizer and water integration: Diluting and mixing liquid or solid inhibitors with a small amount of water or fertilizer mother liquor in a small container, then pouring it into a large fertilizer tank and stirring again to ensure uniform mixing.
10. The application of the urease inhibitor according to claim 9 in urea and compound fertilizer, characterized in that: In the method of applying the urease inhibitor, the effective amount of the urease inhibitor added is 0.01 to 0.16% of the weight of urea; the effective amount of the nitration inhibitor added is 0.05 to 0.09% of the weight of urea.