LIQUID UREASE INHIBITOR FORMULATIONS

Abstract

The present application generally relates to a method for the manufacture of a liquid composition essentially consisting of an organic solvent of the type glycol ether and a urease inhibitor of the type phosphoric triamide and products obtained therewith.

Claims

1-23. (canceled)

24. A method for the manufacture of a liquid composition essentially consisting of an organic solvent of the type glycol ether and a urease inhibitor of the type phosphoric triamide, and optionally a dye system, wherein the method comprises at least the step of maintaining the liquid composition essentially consisting of an organic solvent of the type glycol ether and a urease inhibitor of the type phosphoric triamide, and optionally a dye system, at a holding temperature which is at least above room temperature but below the melt temperature of said urease inhibitor of the type phosphoric triamide, for a holding time period of at least 1 minute.

25. The method according to claim 24, wherein said holding time period ranges between 1 minute and 2 hours.

26. The method according to claim 24, wherein said holding temperature is kept essentially constant during said holding time period.

27. The method according to claim 24, wherein stirring or an ultrasonic treatment is applied during said holding time period.

28. The method according to claim 24, wherein the liquid composition essentially consisting of an organic solvent of the type glycol ether and a urease inhibitor of the type phosphoric triamide, and optionally a dye system, does not comprise any other substances other than an organic solvent of the type glycol ether and a urease inhibitor of the type phosphoric triamide, and optionally a dye system.

29. The method according to claim 24, wherein the urease inhibitor of the type phosphoric triamide is a compound of formula (I): ##STR00003## wherein: X is oxygen or sulphur; R.sup.1 is selected from the group consisting of alkyl, cycloalkenyl, aralkyl, aryl, alkenyl, alkynyl, and cycloalkyl; and R.sup.2 is selected from the group consisting of hydrogen, alkyl, cycloalkenyl, aralkyl, aryl, alkenyl, alkynyl, and cycloalkyl, or R.sup.1 and R.sup.2 together may form an alkylene or alkenylene chain which may optionally include one or more heteroatoms of divalent oxygen, nitrogen or sulphur, completing a 4-, 5-, 6-, 7- or 8-membered ring structure; and R.sup.3, R.sup.4, R.sup.5 and R.sup.6 are individually selected from the group consisting of hydrogen and alkyl having 1 to 6 carbon atoms, and R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5 and R.sup.6, when not hydrogen, may each be optionally substituted with one or more selected from the group consisting of trihalomethyl, naphtoxy, alkyl, halogen, arylmercapto, phenoxy, phenyl, nitro, cyano, amino, alkylamino, dialkylamino, alkoxy, mercapto, alkylmercapto, alkylcarbonyl, arylamino, aryl carbonyl, alkoxycarbonyl, carboxy, diarylamino, and carbonamide.

30. The method according to claim 24, wherein the urease inhibitor is N-(n-butyl) thiophosphoric triamide (nBTPT).

31. The method according to claim 24, wherein the amount of said urease inhibitor of the type phosphoric triamide ranges from 1 to 30 weight %, relative to the total weight of said liquid composition.

32. The method according to claim 24, wherein the organic solvent of the type glycol ether is a compound of formula (II) ##STR00004## wherein: R.sup.7 is C.sub.1-6-alkyl; R.sup.8 is hydrogen or C.sub.1-6-alkyl; n is 1 to 2; and m is 1 to 4.

33. The method according to claim 32, wherein the organic solvent is selected from the group consisting of diethylene glycol monomethyl ether (DEGMME), diethylene glycol monoethyl ether (DEGMEE), diethylene glycol monopropyl ether (DEGMPE), diethylene glycol monobutyl ether (DEGMBE), dipropylene glycol monomethyl ether (DPGMME), dipropylene glycol monoethyl ether (DPGMEE), dipropylene glycol monopropyl ether (DPGMPE), dipropylene glycol monobutyl ether (DPGMBE), triethylene glycol monomethyl ether (TEGMME), triethylene glycol monoethyl ether (TEGMEE), triethylene glycol monopropyl ether (TEGMPE), triethylene glycol monobutyl ether (TEGMBE), and combinations thereof, preferably wherein the organic solvent is diethylene glycol monobutyl ether (DEGMBE).

34. The method according to claim 24, wherein the amount of said organic solvent of the type glycol ether ranges between 55 and 99 weight %, relative to the total weight of said liquid composition.

35. The method according claim 24, wherein an amount of said organic solvent of the type glycol ether is replaced by the same amount of propylene glycol, preferably wherein the ratio glycol ether/propylene glycol is about 1:1.

36. The method according claim 24, further comprising a step wherein an amount of a dye system is added to the liquid composition essentially consisting of an organic solvent of the type glycol ether and a urease inhibitor of the type phosphoric triamide.

37. The method according to claim 36, wherein the amount of said dye system ranges between 0 and 1.0 weight %.

38. A liquid composition essentially consisting of diethylene glycol monobutyl ether (DEGMBE) as a solvent and 10 to 30 weight %, in particular 15 to 25 weight %, more in particular about 25 weight %, relative to the total weight of the liquid solution, of N-(n-butyl) thiophosphoric triamide (nBTPT), characterized in that nBTPT has a crystallization temperature in the liquid composition of less than 12 C.

39. The liquid composition according to claim 38, wherein nBTPT has a crystallization temperature in the liquid composition of less than 14 C., more preferably less than 16 C., even more preferably less than 18 C., even more preferably less than 20 C., even more preferably less than 22 C., even more preferably less than 24 C., and most preferably less than 26 C.

40. A solid particulate urea-based composition, comprising a solid particulate urea-based compound and the liquid composition according to claim 38, wherein the liquid composition forms at least partially a coating on at least part of the particles comprising the urea-based compound, or is incorporated within at least part of the particles comprising the urea-based compound.

41. The solid particulate urea-based composition according to claim 40, wherein the urea-based compound is selected from the group of urea, urea calcium sulphate (UCaS), urea calcium nitrate (UCaN), urea magnesium nitrate (UMgN), urea calcium phosphate (UCaP), urea magnesium phosphate (UMgP), urea superphosphate (USP), urea calcium ammonium nitrate (UCAN), urea ammonium sulphate (UAS), urea ammonium phosphate (UAP), urea potassium salts (UK), urea-based compound NPK fertilizer, and mixtures thereof.

42. The solid particulate urea-based composition according to claim 40, wherein the composition is a physical blend of the urea-based compound in particulate form and one or more components selected from the group of nitrates, phosphates, sulphates and chlorides in particulate form, selected from the group of: ammonium nitrate, calcium nitrate, calcium ammonium nitrate, sodium nitrate, ammonium sulphate nitrate, potassium ammonium nitrate, ammonium phosphate, such as mono-ammonium phosphate (MAP) and di-ammonium phosphate (DAP), calcium bis(dihydrogen orthophosphate), super phosphate, triple superphosphate, rock phosphate, potassium sulphate, potassium magnesium sulphate, ammonium sulphate (AS), urea ammonium sulphate, urea calcium ammonium nitrate, urea ammonium sulphate, potassium chloride (MOP), potassium sulphate (SOP), urea potassium salts (UK), urea-based compound NPK fertilizer, or mixtures thereof.

43. A liquid urea-based composition, comprising a dissolved urea-based compound and the liquid composition according to claim 38, wherein said liquid composition is intimately mixed with the urea-based compound, preferably selected from the group of urea, urea ammonium nitrate (UAN), urea calcium nitrate (UCaN), or mixtures thereof, dissolved in a solvent, preferably in water.

44. A urea-containing fertilizer comprising the solid particulate urea-based composition according to claim 40.

Description

DESCRIPTION OF FIGURES

[0168] FIG. 1: Stability of nBTPT in different liquid nBTPT solutions with storage in closed plastic containers at room temperature (20 C.) after 15 days of storage at room temperature. [A=25% nBTPT in DEGMBE/PG 1:1, B=25% nBTPT in DEGMME, C=25% nBTPT in DEGMBE].

[0169] FIG. 2: Stability of nBTPT in different liquid nBTPT solutions on urea granules with storage at 70 C. in closed plastic containers after 11 days. [A=17.5% nBTPT in PG on urea, B=25% nBTPT in DEGMBE on urea, C=25% nBTPT in DEGMBE/PG 1:1 on urea].

DETERMINATION OF STABILITY OF nBTPT

[0170] HPLC analysis of nBTPT-content

[0171] HPLC analysis of nBTPT is done as described in the procedure CEN 15688-2007.

Products

[0172] Solid N-(n-butyl)thiophosphoric triamide was obtained from Sunfit Chemical Co. (China) (CAS-Nr. 94317-64-3), as a white crystalline solid with a melting point of 58-60 C.

[0173] Propylene glycol was obtained from Amresco (a VWR company) (CAS-Nr. 57-55-6), as colourless, odourless viscous liquid with a boiling point of 188.2 C.

[0174] Diethylene glycol monomethyl ether (DEGMME) was obtained from VWR chemicals and reagents Merck and from INEOS N.V. (Zwijndrecht, Belgium) (CAS-Nr. 111-77-3), as colourless, odourless viscous liquid with a boiling point of 190-196 C.

[0175] Diethylene glycol monobutyl ether (DEGMBE) was obtained from VWR chemicals and reagents Merck and from INEOS N.V. (Zwijndrecht, Belgium) (CAS-Nr. 111-34-5), as colourless, odourless viscous liquid with a boiling point of 226-234 C.

[0176] The flash point of propylene glycol is 130 C. For comparison, the flash point of Agrotain is 81.1 C., which is considerably lower.

[0177] The toxicity oral rat LD50 is 20000 mg/kg for propylene glycol, 6450 mg/kg for DEGMME and 5660 mg/kg for DEGMBE. For comparison, the toxicity of NMP (major solvent in Agrotain) oral rat LD50 is 3914 mg/kg, which is considerably lower.

[0178] Experiment 1-Crystallization Stability Under Stirred Conditions of nBTPT in Glycol Ether Type Solvents at Lower Temperatures.

[0179] To determine the crystallization temperature of nBTPT in a glycol ether type solvent mixture at different concentrations under stirred conditions, an acetone bath was cooled between 10 and 25 C. with the addition of liquid nitrogen and the crystallization temperature was measured with a thermometer logging while stirring, for several samples. The solutions of nBTPT in the glycol ether type solvent mixture were prepared by heating up the mixture of nBTPT and the specific solvent to 45 C., followed by stirring for 15 minutes at 45 C. until a clear solution was achieved. The results are shown in Table 2.

TABLE-US-00002 TABLE 2 Crystallization temperature ( C.) under stirred condition Maintaining nBTPT solutions at 45 C. for 15 min 25% nBTPT in PG +9.3 C. 25% nBTPT in DEGMBE/PG 1:1 9.1 C. 25% nBTPT in DEGMME .sup.10 C. 25% nBTPT in DEGMBE 18.9 C. 26% nBTPT in DEGMBE 12.8 C. 27.5% nBTPT in DEGMBE 5.6 C. 30% nBTPT in DEGMBE +4.5 C. 32.5% nBTPT in DEGMBE +11.5 C. 35% nBTPT in DEGMBE +20.0 C. 40% nBTPT in DEGMBE Crystallized at room temperature

[0180] A solution of 25% nBTPT in DEGMBE was also made at room temperature, followed by stirring for 4 hours until a clear solution was achieved. The crystallization temperature under stirred conditions was determined and compared to the same solution prepared at 45 C. The results are shown in Table 2.

TABLE-US-00003 TABLE 3 Crystallization temperature ( C.) under stirred condition room temperature for 4 hours 45 C. for 15 min 25% nBTPT in DEGMBE 4.7 18.9

[0181] There is clearly a beneficial effect of the heating method on the crystallization temperature. As an extra step in the preparation procedure of the solutions of nBTPT in DEGMBE, said heating at or above 40 C. is recommended for the best results.

[0182] Experiment 2-Crystallization Stability Under Stagnant Conditions of nBTPT in Glycol Type Solvents at Lower Temperatures.

[0183] To determine the crystallization stability of nBTPT in a glycol type solvent mixture under stagnant conditions, the specific nBTPT solutions were placed in a freezer at different temperatures and followed up in time.

[0184] The solutions of nBTPT in the glycol type solvent mixture were prepared by heating up the mixture of nBTPT and the specific solvent to 45 C., followed by stirring for 15 minutes at 45 C. until a clear solution was achieved. The results are shown in Table 4.

TABLE-US-00004 TABLE 4 Crystallization stability under stagnant condition 16.5 C. 16.5 C. 26.0 C. for 24 h for 72 h for 120 h 25% nBTPT in crystallized crystallized crystallized propylene glycol 25% nBTPT in n.a. n.a. crystallized DEGMBE/PG 1:1 25% nBTPT in DEGMBE Clear liquid Clear liquid Clear liquid 26% nBTPT in DEGMBE Partially crystallized crystallized crystallized n.a. = not analyzed

[0185] Experiment 3-Stability of nBTPT in Solutions

[0186] The stability of nBTPT in some of the above listed solutions was followed over time when stored at room temperature. The results are summarized in FIG. 1. All formulations seems to be very stable at room temperature, with almost a full recovery after 15 days of storage.

[0187] Experiment 4-Stability of nBTPT in Glycol Type Solvent Mixtures on Urea Granules.

[0188] For lab scale experiments, nBTPT was applied onto urea by adding 1.2 kg of urea-based compound to a lab scale drum. In a next step, the nBTPT material was slowly added. A residence time of 10 minutes was applied and the rotating speed of the drum was consequently the same in each experiment.

[0189] An accelerated stability test was done storing these samples at elevated temperature at 70 C. in a closed plastic container.

[0190] For this experiment, urea granules were coated with 550 ppm of the liquid composition according to the invention. Subsequently, the granules were stored for 11 days in closed plastic containers at 70 C. and the decomposition of nBTPT was followed. The results are shown in FIG. 2.

[0191] Overall, all tested nBTPT liquid formulations on urea granules seemed to have similar stability under this severe storage condition. 25% nBTPT in DEGMBE (with or without the co-solvent PG) on urea showed a comparable stability as nBTPT in propylene glycol on urea and showed a +/20% nBTPT degradation in 11 days at 70 C. Propylene glycol is used as a standard main solvent applied in commercial nBTPT formulations like N Yield and Agrotain Ultra.

[0192] Experiment 5-Odour

[0193] The odour was determined for all nBTPT sources as such, applied onto urea granules in a concentration of 500 ppm. A qualitative overview is given in Table 5.

TABLE-US-00005 TABLE 5 Smell of the nBTPT Smell from Urease inhibitor formulation granules Remark BASF Limus strong none very intensive odour N Yield strong strong DMSO smell Agrotain Ultra strong strong very intensive odour Rhodia Ag-Rho medium weak N Protect B nBTPT powder strong none 25% nBTPT in weak weak pleasant smell DEGMBE

[0194] All nBTPT sources have a significant smell/odour. However, compared to the commercial sources, the liquid composition according to the invention has a weak odour as such and no significant odour when applied onto urea granules.

[0195] Experiment 6: Production of a Commercial Batch

[0196] The following 1000 kg batch was produced:

TABLE-US-00006 DEGMBE 742.44 kg nBTPT (purity: about 98.0%) 255.10 kg (25%) Duasyn Brilliant Red F3B-SF Liquid 2.46 kg Total 1000.0 kg

[0197] Protocol [0198] 1. Charge a vessel with 742.44 kg DEGMBE. [0199] 2. Start stirrer and heat to 45 C. [0200] 3. Charge 255.1 kg of nBTPT gradually whilst maintaining the temperature at 45 C. [0201] 4. Mix for 15 minutes after last powder addition. [0202] 5. Check if nBTPT is fully dissolved; if undissolved powder is present, mix for 10 minutes and re-check. [0203] 6. Add 2.46 kg Duasyn Brilliant Red F3B-SF Liquid. [0204] 7. Mix for 5 minutes. [0205] 8. Cool down to room temperature.

[0206] Target Specification:

TABLE-US-00007 Appearance: clear red solution nBTPT content 25.0% w/w