Amino alcohol solutions of N-(n-butyl)thiophosphoric triamide (NBPT) and urea fertilizers using such solutions as urease inhibitors

Abstract

A method of producing reduced volatility of urea fertilizers comprising: dissolving N-(n-butyl)-thiophosphoric triamide (NBPT) in an amino alcohol having the formula 1 —(H) x —N—((CH 2 ) m —OH) n where m is 1-3, x is 0 or 1, and n is 2 when x is 1 and 3 when x is 0: or the formula 2 —(H) y —N—((CH 2 )—CHOH—CH 3 ) z such that the length of the carbon chain where the secondary hydroxyl group is located is 3, y is 0 or 1, and z is 2 when y is 1 and 3 when y is 0 to form an NBPT solution; and combining a urea fertilizer in granular or liquid form with the NBPT solution.

1 . A method of preparing a solution for use in reducing the volatility of urea fertilizers comprising dissolving N-(n-butyl)-thiophosphoric triamide (NBPT) in an amino alcohol having the formula 1 —(H) x —N—((CH 2 ) m —OH) n  where m is 1-3, x is 0 or 1, and n is 2 when x is 1 and 3 when x is 0: or the formula 2 —(H) y —N—((CH 2 )—CHOH—CH 3 ), such that the length of the carbon chain where the secondary hydroxyl group is located is 3, y is 0 or 1, and z is 2 when y is 1 and 3 when y is 0. 
   
   
       2 . The method of  claim 1 , wherein said amino alcohol is selected from the group consisting of diethanolamine, dipropanolamine, triethanolamine, tripropanolamine, diisopropanolamine, triisopropanolamine, and mixtures thereof. 
   
   
       3 . The method of  claim 1 , wherein from about 15% to about 40% by weight NBPT is dissolved in said amino alcohol. 
   
   
       4 . The method of  claim 1 , wherein said NBPT is dissolved in said amino alcohol and a co-solvent selected from the group consisting of ethylene glycol and propylene glycol. 
   
   
       5 . The method of  claim 1 , wherein said amino alcohol is mixed with a co-solvent. 
   
   
       6 . A solution for use in reducing the volatility of urea fertilizers comprising N-(n-butyl)-thiophosphoric triamide (NBPT) dissolved in an amino alcohol having the formula 1 —(H) x —N—((CH 2 ) m —OH), where m is 1-3, x is 0 or 1, and n is 2 when x is 1 and 3 when x is 0: or the formula 2 —(H) y —N—((CH 2 )—CHOH—CH 3 ) z  such that the length of the carbon chain where the secondary hydroxyl group is located is 3, y is 0 or 1, and z is 2 when y is 1 and 3 when y is 0. 
   
   
       7 . The solution of  claim 6 , wherein said amino alcohol is selected from the group consisting of diethanolamine, dipropanolamine, triethanolamine, tripropanolamine, diisopropanolamine, triisopropanolamine, and mixtures thereof. 
   
   
       8 . The solution of  claim 6 , wherein from about 15% to about 40% by weight NBPT is dissolved in said amino alcohol. 
   
   
       9 . The solution of  claim 6 , further including a co-solvent. 
   
   
       10 . The solution of  claim 6 , wherein said solution is diluted with aqueous mixture. 
   
   
       11 . A method of producing reduced volatility of urea fertilizers comprising:
 a) dissolving N-(n-butyl)-thiophosphoric triamide (NBPT) in an amino alcohol having the formula 1 —(H) x —N—((CH 2 ) m —OH) n  where m is 1-3, x is 0 or 1, and n is 2 when x is 1 and 3 when x is 0: or the formula 2 —(H) y —N—((CH 2 )—CHOH—CH 3 ) z  such that the length of the carbon chain where the secondary hydroxyl group is located is 3, y is 0 or 1, and z is 2 when y is 1 and 3 when y is 0 to form an NBPT solution; and   b) combining said NBPT solution with said urea fertilizer.   
   
   
       12 . The method of  claim 11 , wherein said urea fertilizer is in the form of granules and said NBPT solution is coated on said granules. 
   
   
       13 . The method of  claim 11 , wherein said fertilizer granules are coated with from about 0.050% to about 0.25% NBPT. 
   
   
       14 . The method of  claim 11 , wherein said urea fertilizer is an aqueous urea fertilizer solution and said NBPT solution is mixed with said aqueous solution. 
   
   
       15 . The method of  claim 11 , wherein said aqueous urea fertilizer solution contains from about 0.050% to about 0.25% NBPT. 
   
   
       16 . The method of  claim 11 , wherein said amino alcohol is selected from the group consisting of diethanolamine, dipropanolamine, triethanolamine, tripropanolamine, diisopropanolamine, triisopropanolamine, and mixtures thereof. 
   
   
       17 . The method of  claim 11 , wherein from about 15% to about 40% by weight NBPT is dissolved in said amino alcohol. 
   
   
       18 . A method of producing reduced volatility of urea fertilizers comprising:
 a) dissolving N-(n-butyl)-thiophosphoric triamide (NBPT) in an amino alcohol having the formula 1 —(H) x —N—((CH 2 ) m —OH) n  where m is 1-3, x is 0 or 1, and n is 2 when x is 1 and 3 when x is 0: or the formula 2 —(H) y —N—((CH 2 )—CHOH—CH 3 ) z  such that the length of the carbon chain where the secondary hydroxyl group is located is 3, y is 0 or 1, and z is 2 when y is 1 and 3 when y is 0 to form an NBPT solution; and   b) combining a granular urea fertilizer with said NBPT solution.   
   
   
       19 . The method of  claim 18 , further including the step of coating said fertilizer granules with powdered micronutrients 
   
   
       20 . The method of  claim 18 , wherein said NBPT solution is diluted with an aqueous mixture prior to addition of powdered micronutrients. 
   
   
       21 . The method of  claim 18 , wherein said granular urea fertilizer with added micronutrients contains from about 0.050% to about 0.25% NBPT. 
   
   
       22 . A method of producing reduced volatility liquid urea fertilizer comprising:
 a) dissolving N-(n-butyl)-thiophosphoric triamide (NBPT) in an amino alcohol having the formula 1 —(H) x —N—((CH 2 ) m —OH) n  where m is 1-3, x is 0 or 1, and n is 2 when x is 1 and 3 when x is 0: or the formula 2 —(H) y —N—((CH 2 )—CHOH—CH 3 ), such that the length of the carbon chain where the secondary hydroxyl group is located is 3, y is 0 or 1, and z is 2 when y is 1 and 3 when y is 0 to form an NBPT solution; and   b) mixing said NBPT solution with an aqueous solution of urea fertilizer.   
   
   
       23 . The method of  claim 22 , wherein said amino alcohol is selected from the group consisting of diethanolamine, dipropanolamine, triethanolamine, tripropanolamine, diisopropanolamine, triisopropanolamine, and mixtures thereof. 
   
   
       24 . The method of  claim 22 , wherein from about 15% to about 40% by weight NBPT is dissolved in said amino alcohol. 
   
   
       25 . The method of  claim 22 , wherein sufficient NBPT solution is mixed with said aqueous solution to produce an aqueous fertilizer containing from about 0.050% to about 0.25% NBPT. 
   
   
       26 . The method of  claim 22 , wherein said urea fertilizer is an aqueous mixture of urea and ammonium nitrate.