Liquid compositions containing urease inhibitors and glycol alkyl ethers and methods of making and use thereof

Abstract

The present invention provides improved solvent systems for the preparation of liquid formulations of urease or nitrification inhibitors, specifically NBPT, comprising alkylene glycol alkyl ethers. The solvent systems provided good solubility of the urease inhibitor as well as at least one of improved stability, lower flammability, lower toxicity, improved cold temperature storage, improved handling, improved adsorption onto and/or solubility with solid media such as UFP or urea. Methods of making and using the compositions are also provided.

What is claimed is: 
     
         1 . A composition comprising:
 a urea-based fertilizer;   a urease inhibitor; and   an alkylene glycol alkyl ether.   
     
     
         2 . The composition of  claim 1 , wherein the alkylene glycol alkyl ether is selected from the group consisting of diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monopentyl ether, diethylene glycol monoisopropyl ether, diethylene glycol monoisobutyl ether, diethylene glycol monohexyl ether, triethylene glycol monomethyl ether, triethylene glycol monopropyl ether, triethylene glycol monobutyl ether, triethylene glycol monopentyl ether, triethylene glycol monoisopropyl ether, triethylene glycol monoisobutyl ether, triethylene glycol monohexyl ether, tetraethylene glycol monomethyl ether, tetraethylene glycol monoethyl ether, tetraethylene glycol monopropyl ether, tetraethylene glycol monobutyl ether, tetraethylene glycol monopentyl ether, tetraethylene glycol monoisopropyl ether, tetraethylene glycol monoisobutyl ether, tetraethylene glycol monohexyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monobutyl ether, dipropylene glycol monopentyl ether, dipropylene glycol monoisopropyl ether, dipropylene glycol monoisobutyl ether, dipropylene glycol monohexyl ether, tripropylene glycol monoethyl ether, tripropylene glycol monopropyl ether, tripropylene glycol monobutyl ether, tripropylene glycol monopentyl ether, tripropylene glycol monoisopropyl ether, tripropylene glycol monoisobutyl ether, tripropylene glycol monohexyl ether, and combinations thereof 
     
     
         3 . The composition of  claim 1 , wherein the alkylene glycol alkyl ether is triethylene glycol monobutyl ether. 
     
     
         4 . The composition of  claim 1 , wherein the urease inhibitor is a phosphoric or thiophosphoric triamide of the general formula (II),
   X=P(NH 2 ) 2 NR 1 R 2    (II)
   where X=oxygen or sulfur, and R 1  and R 2  are independently selected from hydrogen, C 1 -C 12  alkyl, C 3 -C 12  cycloalkyl, C 6 -C 14  aryl, C 2 -C 12  alkenyl, C 2 -C 12  alkynyl, C 5 -C 14  heteroaryl, C1-C14 heteroalkyl, C2-C14 heteroalkenyl, C 2 -C 14  heteroalkynyl, and C 3 -C 12  cycloheteroalkyl.   
     
     
         5 . The composition of  claim 1 , wherein the urease inhibitor is N-(n-butyl)thiophosphoric triamide (NBPT). 
     
     
         6 . The composition of  claim 1 , further comprising N-methyl pyrrolidone. 
     
     
         7 . The composition of  claim 1 , further comprising a nitrification inhibitor. 
     
     
         8 . The composition of  claim 7 , wherein the nitrification inhibitor comprises dicyandiamide (DCD). 
     
     
         9 . The composition of  claim 1 , further comprising a cosolvent selected from the group consisting of a glycol, glycol ester, polyglycol ester, glycerol, and glycerol ester. 
     
     
         10 . The composition of  claim 9 , wherein the cosolvent is propylene glycol. 
     
     
         11 . The composition of  claim 1 , further comprising one or more components selected from the group consisting of a dye, conditioner and xanthan gum. 
     
     
         12 . The composition of  claim 1 , wherein the composition comprises urea formaldehyde polymer (UFP). 
     
     
         13 . The composition of  claim 1 , wherein the composition comprises the urea-based fertilizer in an amount of from about 90% to about 99% by weight 
     
     
         14 . The composition of  claim 12 , wherein the urease inhibitor is N-(n-butyl)thiophosphoric triamide (NBPT) and wherein the composition comprises the NBPT, alkylene glycol alkyl ether, and UFP in a combined amount of about 0.02 to about 0.5% by weight of the composition. 
     
     
         15 . The composition of  claim 12 , further comprising dicyandiamide (DCD) in an amount of about 0.05 to about 1.1% by weight of the composition. 
     
     
         16 . A method for making the composition of  claim 1 , comprising combining the urea-based fertilizer with a mixture comprising the urease inhibitor and the alkylene glycol alkyl ether. 
     
     
         17 . The method of  claim 16 , wherein the mixture is in solid form. 
     
     
         18 . The method of  claim 16 , wherein the mixture is in liquid form. 
     
     
         19 . The method of  claim 16 , wherein the urea-based fertilizer comprises urea in molten form. 
     
     
         20 . The method of  claim 16 , wherein the urea-based fertilizer comprises urea in solid form.