Herbicide microemulsion-forming-concentrates, microemulsions, and methods

Abstract

Described are herbicide compositions, in particular, herbicide compositions that are prepared from microemulsions containing herbicide compound in acid form, and methods of their preparation and use.

1 . A method of controlling plant growth, the method comprising 
 providing a microemulsion forming concentrate comprising herbicide compound in acid form dissolved in surfactant,    combining the microemulsion forming concentrate with water and acidifying agent, to form a microemulsion having a pH below the pKa of the herbicide compound in acid form, and    applying the microemulsion, having a pH below the pKa of the herbicide compound in acid form, to a plant, to control plant growth.    
   
   
       2 . The method of  claim 1  wherein the microemulsion forming concentrate consists essentially of herbicide compound in acid form and surfactant.  
   
   
       3 . The method of  claim 1  wherein the microemulsion forming concentrate contains no added organic solvent.  
   
   
       4 . The method of  claim 1  wherein the microemulsion forming concentrate comprises surfactant selected from the group consisting of an anionic surfactant, a cationic surfactant, a non-ionic surfactant, and combinations thereof.  
   
   
       5 . The method of  claim 1  wherein the microemulsion forming concentrate comprises surfactant selected from the group consisting of a non-ionic linear or branched alcohol ethoxylate surfactant, an anionic phosphoric acid ester surfactant, a cationic ethoxylated tallow amine surfactant, and combinations thereof.  
   
   
       6 . The method of  claim 1  wherein the microemulsion forming concentrate comprises surfactant selected from the group consisting of: an ethoxylated linear alcohol; an ethoxylated amine; an ethoxylated amide; a phosphate ester; a branched alcohol ethoxylate; an ethoxylated alkyl phenol; an ethoxylated fatty acid; a sorbitan laurate; a sorbitan oleate; a propylated, ethoxylated fatty acid, alcohol, or alkyl phenol; and combinations thereof.  
   
   
       7 . The method of  claim 1  wherein the herbicide compound in acid form is selected from the group consisting of 2,4-dichlorophenoxyacetic acid, dicamba acid (3,6-dichloro-O-anixic acid), 4-methyl-4-chloropnenoxyacetic acid, 2(-2-methyl-4-chlorophenoxy)propionic acid, 3,5,6-trichloro-2-pyridyloxyacetic acid (triclopyr acid), fluazifop acid, [(4-amino-3,5-dichloro-6-fluoro-2-pyridinyl)oxy]acetic acid (fluoroxypyr acid), and combinations thereof.  
   
   
       8 . The method of  claim 1  wherein the microemulsion forming concentrate comprises 2,4-D acid dissolved in nonionic ethoxylated linear alcohol surfactant.  
   
   
       9 . The method of  claim 1  wherein the microemulsion forming concentrate comprises 2,4-D acid dissolved in nonionic ethoxylated alkyl phenol surfactant.  
   
   
       10 . The method of  claim 1  wherein the microemulsion forming concentrate comprises 2,4-D acid dissolved in castor oil ethoxylate surfactant.  
   
   
       11 . The method of  claim 1  wherein the microemulsion forming concentrate comprises 2,4-D acid dissolved in a combination of sorbitan laurate and sorbitan oleate surfactant.  
   
   
       12 . The method of  claim 1  wherein the microemulsion forming concentrate comprises 2,4-D acid dissolved in ethoxylated triserylphenol surfactant.  
   
   
       13 . The method of  claim 1  wherein the microemulsion forming concentrate comprises 2,4-D acid dissolved in nonionic ethoxylated branched alcohol surfactant.  
   
   
       14 . The method of  claim 1  wherein the microemulsion forming concentrate comprises fluoroxypyr acid dissolved in nonionic ethoxylated linear alcohol surfactant.  
   
   
       15 . The method of  claim 1  wherein the microemulsion forming concentrate comprises fluoroxypyr acid dissolved in ethoxylated tallow amine surfactant.  
   
   
       16 . The method of  claim 1  wherein the microemulsion comprises: 
 from about 0.05 to about 7 volume percent microemulsion-forming-concentrate comprising from about 10 to about 40 parts by weight herbicide compound in acid form and from about 60 to about 90 parts by weight surfactant, and    from about 93 to about 99.95 volume percent water.    
   
   
       17 . The method of  claim 1  wherein the acidifying agent is selected from the group consisting of: hydrochloric acid, nitric acid, acetic acid, phosphoric acid, polyphosphoric acid, perchloric acid, sulfuric acid, and combinations thereof.  
   
   
       18 . A microemulsion forming concentrate comprising from 2,4-D acid dissolved in surfactant.  
   
   
       19 . The microemulsion forming concentrate of  claim 18  wherein the surfactant is selected from the group consisting of nonionic ethoxylated linear alcohol surfactant, nonionic ethoxylated alkyl phenol surfactant, castor oil ethoxylate surfactant, a combination of sorbitan laurate and sorbitan oleate surfactant, and ethoxylated triserylphenol surfactant.  
   
   
       20 . The microemulsion forming concentrate of  claim 19  comprising from about 10 to about 40 parts by weight 2,4-D acid dissolved in from about 60 to about 90 parts by weight surfactant.