Auxin herbicidal mixtures

Abstract

Herbicidal mixtures comprising an auxin herbicide and an adjuvant comprising a salt having a quaternary ammonium cation and/or a phosphonium cation are described. The adjuvant reduces the volatility of the auxin herbicide and/or counteracts the negative impact on the volatility of the auxin herbicide caused by the addition of a co-herbicide. Methods of preparing the herbicidal mixtures are also described.

What is claimed is: 
     
         1 . A method of preparing a herbicidal mixture, the method comprising:
 combining an auxin herbicide comprising a first cation and an adjuvant comprising a salt comprising a second cation, wherein the salt is selected from the group consisting of:   (a) an ammonium salt of Formula I   
       
         
           
           
               
               
           
         
       
       wherein R 1 , R 2 , R 3 , and R 4  are independently a C 1 -C 12  hydrocarbyl and X is an agronomically acceptable anion;
 (b) a salt containing a nitrogen heterocycle of Formula II 
 
       
         
           
           
               
               
           
         
       
       wherein A is a 5 or 6-membered heterocyclic ring; R 5  is a C 1 -C 20  alkyl; R 6  is hydrogen or a C 1 -C 6 alkyl, and X is an agronomically acceptable anion;
 (c) a phosphonium salt of Formula III 
 
       
         
           
           
               
               
           
         
       
       wherein R 7 , R 8 , R 9 , and R 10  are independently a C 1 -C 12  hydrocarbyl and X is an agronomically acceptable anion; and mixtures thereof, and wherein the herbicidal mixture has a total herbicide concentration no greater than about 40% by weight acid equivalent (a.e). 
     
     
         2 . The method of  claim 1  wherein R 1 , R 2 , R 3 , and R 4  are independently C 1 -C 12  alkyl or benzyl. 
     
     
         3 . The method of  claim 2  wherein R 1 , R 2 , R 3 , and R 4  are independently C 1 -C 6  alkyl. 
     
     
         4 . The method of  claim 1  wherein the salt of Formula I is selected from the group consisting of tetraethylammonium chloride, tributylmethylammonium chloride, tetrabutylammonium chloride, tetrabutylammonium bromide, and dodecyltrimethylammonium chloride. 
     
     
         5 . The method of  claim 1  wherein A is a substituted imidazole ring, a substituted pyridine ring, or a substituted pyrrolidine ring. 
     
     
         6 . The method of  claim 1  wherein R 5  is C 1 -C 12  alkyl. 
     
     
         7 . The method of  claim 1  wherein the salt of Formula II is selected from the group consisting of 1-butyl-1-methyl-pyrrolidinium chloride, 1-ethyl-3-methylimidazolium chloride, 1-butyl-3-methylimidazolium chloride, 1-methyl-3-octylimidazolium chloride, cetylpyridinium chloride, and cetylpyridinium bromide. 
     
     
         8 . The method of  claim 1  wherein R 7 , R 8 , R 9 , and R 10  are independently C 1 -C 12  alkyl. 
     
     
         9 . The method of  claim 1  wherein the salt of Formula III comprises tetrabutylphosphonium chloride. 
     
     
         10 . The method of  claim 1  wherein X is Cl, Br, or OH. 
     
     
         11 . The method of  claim 1  wherein the auxin herbicide is selected from the group consisting of 3,6-dichloro-2-methoxybenzoic acid (dicamba); 2,4-dichlorophenoxyacetic (2,4-D); 4-(2,4-dichlorophenoxy)butanoic acid (2,4-DB); 2-(2,4-dichlorophenoxy)propanoic acid (dichloroprop); 2-(4-chloro-2-methylphenoxy)acetic acid (MCPA); 4-(4-chloro-2-methylphenoxy)butanoic acid (MCPB); 4-amino-3,6-dichloro-2-pyridinecarboxylic acid (aminopyralid); 3,6-dichloro-2-pyridinecarboxylic acid (clopyralid); 2-[(4-amino-3,5-dichloro-6-fluoro-2-pyridinyl)oxy]acetic acid (fluroxypyr); [(3,5,6-trichloro-2-pyridinyl)oxy]acetic acid (triclopyr); 2-(4-chloro-2-methylphenoxy)propanoic acid (mecoprop); 4-amino-3,5,6-trichloro-2-pyridinecarboxylic acid (picloram); 3,7-dichloro-8-quinolinecarboxylic acid (quinclorac); 6-amino-5-chloro-2-cyclopropyl-4-pyrimidinecarboxylic acid (aminocyclopyrachlor); agriculturally acceptable salts or other derivatives of any of these herbicides; racemic mixtures and resolved isomers thereof; and mixtures thereof. 
     
     
         12 . The method of  claim 1  wherein the auxin herbicide comprises a salt of dicamba. 
     
     
         13 . The method of  claim 12  wherein the dicamba salt is selected from the group consisting of the monoethanolamine salt, diethanolamine salt, isopropylamine, diglycolamine salt, potassium salt, sodium salt dimethylamine salt and mixtures thereof. 
     
     
         14 . The method of  claim 13  wherein the dicamba salt is selected from the group consisting of the monoethanolamine salt, diglycolamine salt, potassium salt, dimethylamine salt and mixtures thereof. 
     
     
         15 . The method of  claim 1  wherein the auxin herbicide comprises a salt of 2,4-D. 
     
     
         16 . The method of  claim 1  wherein the herbicidal mixture further comprises a co-herbicide. 
     
     
         17 . The method of  claim 16  wherein the co-herbicide is more acidic in solution than the auxin herbicide. 
     
     
         18 . The method of  claim 16  wherein the co-herbicide has a pKa that is less than about 5. 
     
     
         19 . The method of  claim 16  wherein the co-herbicide is selected from the group consisting of N-(phosphonomethyl)glycine (glyphosate); DL-phosphinothricin (glufosinate); atrazine, acetochlor, fomesafen, flumioxazin, lactofen, sulfentrazone, metribuzin, clethodim, sethoxydim, metolachlor, alachlor, fenoxaprop, fluazifop, haloxyfop-methyl, paraquat, trialkoxydim; and salts and combinations thereof. 
     
     
         20 . The method of  claim 16  wherein the co-herbicide comprises a salt of glyphosate. 
     
     
         21 . The method of  claim 20  wherein the glyphosate salt is selected from the group consisting of the potassium salt, monoammonium salt, diammonium salt, sodium salt, monoethanolamine salt, n-propylamine, isopropylamine, ethylamine, dimethylamine, ethylenediamine, hexamethylenediamine and trimethylsulfonium salt and mixtures thereof. 
     
     
         22 . The method of  claim 21  wherein the glyphosate salt is selected from the group consisting of the potassium salt, monoethanolamine salt, isopropylamine salt, and mixtures thereof. 
     
     
         23 . The method of  claim 1  wherein the adjuvant comprises a surfactant. 
     
     
         24 . The method of  claim 1  wherein the pH of the herbicidal mixture is from about 4 to about 5.5. 
     
     
         25 . The method of  claim 1  wherein the herbicidal mixture further comprises a surfactant. 
     
     
         26 . The method of  claim 25  wherein the surfactant is selected from the group consisting of alkoxylated tertiary etheramines, alkoxylated quaternary etheramines, alkoxylated etheramine oxides, alkoxylated tertiary amines, alkoxylated quaternary amines, alkoxylated polyamines, sulfates, sulfonates, phosphate esters, alkyl polysaccharides, alkoxylated alcohols, amidoalkylamines and combinations thereof. 
     
     
         27 . The method of  claim 1  wherein the herbicidal mixture is a concentrate composition wherein the total herbicide content is from about 10 wt. % a.e. to about 40 wt. % a.e. 
     
     
         28 . The method of  claim 1  wherein the herbicidal mixture is an application mixture wherein the total herbicide content is less than about 10 wt. % a.e. 
     
     
         29 . The method of  claim 28  wherein the herbicidal mixture is an application mixture wherein the total herbicide content is from about 0.1 wt. % a.e. to about 10 wt. % a.e. 
     
     
         30 . The method of  claim 28  wherein the herbicidal mixture further comprises a co-herbicide and the concentration of the co-herbicide in the application mixture is from about 0.5 wt. % a.e. to about 8 wt. % a.e. 
     
     
         31 . The method of  claim 28  wherein the concentration of the auxin herbicide in the herbicidal mixture is from about 0.25 wt. % (a.e.) to about 4 wt. % (a.e.). 
     
     
         32 . The method of  claim 1  wherein the herbicidal mixture further comprises a co-herbicide and the weight ratio of the co-herbicide to auxin herbicide is from about 1:1 to about 3:1 on acid equivalent basis. 
     
     
         33 . The method of  claim 1  wherein the concentration of the adjuvant in the herbicidal mixture is from about 0.1 wt. % to about 10.0 wt. %. 
     
     
         34 - 82 . (canceled)