Process for preparing improved 3,4-dimethyl-1H-pyrazole phosphate formulations

Abstract

The present invention relates to a process for preparing a formulation F for reducing nitrification. The present invention also relates to a formulation F obtainable by the process of the invention. Furthermore, the present invention relates to a process of preparing a fertilizer-nitrification inhibitor mixture, and to a fertilizer-nitrification inhibitor mixture obtainable by this process. Moreover, the present invention relates to a method of fertilizing agricultural soil.

Claims

1. A process for preparing a formulation F for reducing nitrification, said formulation F comprising: from 10 to 50% by weight of 3,4-dimethyl-1H-pyrazole phosphate, from 10 to 50% by weight of phosphoric acid, and from 10 to 60% by weight of water, in each case based on the total weight of formulation F, wherein the process for preparing the formulation F comprises the step of mixing (a) a solution S comprising: from 10 to 22% by weight of 3,4-dimethyl-1H-pyrazole phosphate, from 58 to 70% by weight of 3,4-dimethyl-1H-pyrazole, and from 10 to 30% by weight of water, in each case based on the total weight of the solution S, with (b) water and phosphoric acid, so as to prepare said formulation F.

2. The process according to claim 1, wherein the formulation F comprises: from 10 to 50% by weight of 3,4-dimethyl-1H-pyrazole phosphate, from 30 to 50% by weight of phosphoric acid, and from 10 to 60% by weight of water, in each case based on the total weight of the formulation F.

3. The process according to claim 2, wherein the formulation F comprises: from 30 to 40% by weight of 3,4-dimethyl-1H-pyrazole phosphate, from 35 to 45% by weight of phosphoric acid, and from 20 to 40% by weight of water, in each case based on the total weight of the formulation F.

4. The process according to claim 3 further comprising: preparing a fertilizer-nitrification inhibitor mixture comprising at least one fertilizer and 3,4-dimethyl-1H-pyrazole phosphate by treating at least one fertilizer with the formulation F.

5. The process according to claim 3 further comprising: fertilizing agricultural soil by applying at least one fertilizer and the formulation F.

6. The process according to claim 2 further comprising: preparing a fertilizer-nitrification inhibitor mixture comprising at least one fertilizer and 3,4-dimethyl-1H-pyrazole phosphate by treating the at least one fertilizer with the formulation F.

7. The process according to claim 6 further comprising: fertilizing agricultural soil by applying the fertilizer-nitrification inhibitor mixture to said soil.

8. The process according to claim 2 further comprising: fertilizing agricultural soil by applying at least one fertilizer and the formulation F.

9. The process according to claim 1, wherein from 20 to 30% by weight of the solution S, from 15 to 25% by weight of water and from 40 to 60% by weight of phosphoric acid are mixed with each other in the mixing step, in each case based on the total amount of the resulting mixture.

10. The process according to claim 9, wherein mixing of solution S with water and phosphoric acid is performed by adding the solution S to a mixture of water and phosphoric acid.

11. The process according to claim 1, wherein formulation F comprises: from 30 to 40% by weight of 3,4-dimethyl-1H-pyrazole phosphate, from 35 to 45% by weight of phosphoric acid, and from 20 to 40% by weight of water, in each case based on the total weight of formulation F.

12. The process according to claim 1, wherein the solution S comprises: from 14 to 18% by weight of 3,4-dimethyl-1H-pyrazole phosphate, from 62 to 66% by weight of 3,4-dimethyl-1H-pyrazole, and from 18 to 22% by weight of water, in each case based on the total weight of the solution S.

13. The process according to claim 1, wherein the step of mixing the solution S with water and phosphoric acid is performed without applying heat.

14. The process according to claim 1, wherein the process further comprises the step of preparing the solution S by adding 3,4-dimethyl-1H-pyrazole to a mixture comprising phosphoric acid and water at a temperature of from 30° C. to 80° C., wherein 3,4-dimethyl-1H-pyrazole is provided in an amount of from 63 to 81% by weight, phosphoric acid is provided in an amount of from 5 to 11% by weight, and water is provided in an amount of from 10 to 30% by weight, in each case based on the total weight of the resulting solution S.

15. A solution S comprising: from 10 to 22% by weight of 3,4-dimethyl-1H-pyrazole phosphate, from 58 to 70% by weight of 3,4-dimethyl-1H-pyrazole, and from 10 to 30% by weight of water, in each case based on the total weight of the solution S, wherein the solution S is a precursor for preparing the formulation F as defined in claim 2.

16. A process for preparing the solution S as defined in claim 15 by adding 3,4-dimethyl-1H-pyrazole to a mixture comprising phosphoric acid and water at a temperature of from 30° C. to 80° C., wherein 3,4-dimethyl-1H-pyrazole is provided in an amount of from 63 to 81% by weight, phosphoric acid is provided in an amount of from 5 to 11% by weight, and water is provided in an amount of from 10 to 30% by weight, in each case based on the total weight of the resulting solution S.

17. A solution S obtained by the process according to claim 16.

18. The solution S according to claim 15 comprising: from 14 to 18% by weight of 3,4-dimethyl-1H-pyrazole phosphate, from 62 to 66% by weight of 3,4-dimethyl-1H-pyrazole, and from 18 to 22% by weight of water, in each case based on the total weight of the solution S.

Description

EXAMPLES

Example 1

(1) Preparation of a solution S1 comprising about 16% by weight of 3,4-dimethyl-1H-pyrazole phosphate (DMPP), about 64% by weight of 3,4-dimethyl-1H-pyrazole (DMP) and about 30% by weight of water, based on the total weight of the solution S1.

(2) The following amounts according to Table 1 were used.

(3) TABLE-US-00001 TABLE 1 Amount [% by weight] DMP (a.i.: 98.0%) 73.45% Orthophosphoric acid (85% in water) 9.41% Water Add to 100%

(4) Water and Orthophosphoric acid (H.sub.3PO.sub.4) were charged to a vessel with a heating unit. Crushed DMP was slowly added under stirring, to obtain a white and viscous mixture. The mixture was heated to 60° C. and DMP addition was completed. The viscosity decreased, and a clear, brownish and low viscous solution was obtained.

Example 2

(5) Preparation of a formulation F1 comprising about 35% by weight of 3,4-dimethyl-1H-pyrazole phosphate (DMPP), about 38% by weight of orthophosphoric acid, and about 28% by weight of water, based on the total weight of the formulation F1 using solution S1

(6) The following amounts according to Table 2 were used.

(7) TABLE-US-00002 TABLE 2 Amount [% by weight] Solution S1 (DMPP: 16%, DMP: 64%) 24.17% Orthophosphoric acid (85% in water) 55.65% Water Add to 100%

(8) Water and Orthophosphoric acid (H.sub.3PO.sub.4) were charged to a vessel with a heating unit. Solution S1 was added. The temperature increases due to neutralization enthalpy so that in general no additional heating is required. A light turbid solution of DMPP was obtained.

(9) Cold stability was tested as follows: Samples of the formulation F1 were put on storage at different temperatures for 1 week. Then traces of DMPP seeding crystals were added and the mixture was stored for another week at the same temperature. Then, the samples were visually investigated for crystals.

(10) It was observed that formulation F1 only crystallized below 20° C. When the crystallized solution is slowly heated it becomes a clear solution at approx. 25° C.

Comparative Example 3

(11) Preparation of formulation F2 comprising about 35% by weight of 3,4-dimethyl-1H-pyrazole phosphate (DMPP), about 38% by weight of orthophosphoric acid, and about 28% by weight of water, based on the total weight of the formulation F2 starting from crystalline DM PP.

(12) The following amounts according to Table 3 were used.

(13) TABLE-US-00003 TABLE 3 Amount [% by weight] DMPP (a.i.: 98.4%) 35.73% Orthophosphoric acid (85% in water) 44.19% Water Add to 100%

(14) Water and Orthophosphoric acid (H.sub.3PO.sub.4) were charged to a vessel with a heating unit. DMPP was added under stirring and dissolved. Heating to 60° C. was required for complete dissolution of DMPP. A clear solution of DMPP was obtained, which crystallized below 30° C.

(15) Cold stability was tested as described in Example 2.

(16) It was observed that formulation F2 crystallized already below 30° C. When the crystallized solution is slowly heated it becomes a clear solution at approx. 40° C.