Enhancement of herbicidal activity of tetraaluminum salts of N-phosphonomethylglycine

A herbicidal composition comprising PA0 (a) a herbicidally effective amount of a tetraaluminum salt of N-phosphonomethylglycine; and PA0 (b) from 0.5 to 50% by weight polyethoxylated amine surfactant of the formula ##STR1## where R is tallow oil having an average of 18 carbon atoms and x+y total 15.

BACKGROUND OF THE INVENTION 
This invention relates to a herbicidal composition containing a 
tetraaluminum salt of N-phosphonomethylglycine which has enhanced 
herbicidal activity by virtue of the inclusion in the herbicidal 
composition of a polyethoxylated tallow amine. 
Herbicides are widely used by farmers, commercial agricultural companies, 
and other industries in order to increase crop yields for such staple 
crops as corn, soybeans, rice, and the like, and to eliminate weed growth 
along highways, railroad rights-of-way, and other areas. Herbicides are 
effective in killing or controlling unwanted weeds which compete for soil 
nutrients with the crop plants, and by reason of the fact that they kill 
weeds, are responsible for improving the aesthetic appearance of highway 
and railroad rights-of-way. There are a number of different types of 
herbicides presently sold commercially, and these fall into two general 
categories. The categories are pre-emergence and post-emergence 
herbicides. The pre-emergence herbicides are normally incorporated into 
the soil or surface applied prior to the emergence of the weed plants from 
the soil, and the post-emergence herbicides are normally applied to the 
plant's foliage after emergence of the weeds or other unwanted plants from 
the soil. 
One of the earliest post-emergence herbicides used commercially was 2,4-D 
(2,4-dichlorophenoxyacetic acid). After a number of years of use of this 
and similar compounds such as 2,4,5-T (2,4,5-trichlorophenoxy acetic 
acid), it was found that certain decomposition products of these 
herbicides and contaminants were long lasting and were not readily 
biodegradable. While there has been some dispute between governmental 
agencies and commercial interests regarding the effects of residual 
products of 2,4,5-T and similar compounds, the agencies nevertheless 
restricted the use of these herbicides in the United States some years 
ago. Since that time, efforts have been made to develop herbicides which 
are biodegradable into harmless residues within a relatively short time 
after their application. 
One such compound, which has been found to be biodegradable, yet which is 
effective as a herbicide and plant growth regulator when employed at lower 
rates, is N-phosphonomethylglycine and various salts thereof. 
N-Phosphonomethylglycine and certain agriculturally effective salts have 
been approved for use by the U.S. Government, and, as a consequence, this 
herbicide has become extremely successful commercially. 
THE PRIOR ART 
N-Phosphonomethylglycines, and certain soluble salts thereof, can be made 
in a number of different ways. One such method, as described in U.S. Pat. 
No. 3,160,632 (Toy et al., Dec. 8, 1964) is to react 
N-phosphinomethylglycine (glycinemethylenephosphinic acid) with mercuric 
chloride in a water solvent at reflux temperature, and subsequently 
separating the reaction products. Other methods include the reaction of 
ethyl glycinate with formaldehyde and diethylphosphite. The latter method 
is described in U.S. Pat. No. 3,799,758 (Franz, Mar. 26, 1974). In 
addition, there is a whole series of patents, relating to 
N-phosphonomethylglycines, their salts, and derivatives thereof, described 
as being useful herbicides and plant growth regulators. Such additional 
patents relating to the N-phosphonomethylglycines, methods of application, 
methods of preparation, salts, and derivatives, include U.S. Pat. Nos. 
3,868,407, 4,197,254, and 4,199,354, among others. 
Specific salts of N-phosphonomethylglycine which have been disclosed to be 
herbicidally effective are the sulfonium and sulfoxonium salts. 
Other salts are constantly being sought which are more economically and 
agriculturally efficient or cost effective than those previously known, or 
are easier to produce. 
It has been found that certain metal salts, particularly the tetraaluminum 
salt of N-phosphonomethylglycine, is an effective herbicide, however, such 
salts have low solubility properties in water and thus their herbicidal 
activity is substantially limited as a consequence of this. 
A reason for this has to do with the way that herbicidal compositions are 
applied by the farmer in the field. For shipping purposes, herbicidal 
compositions are formulated into dusts, wettable powders, granular 
pellets, concentrated emulsions and encapsulated granules. Once the 
herbicide is purchase by the farmer and carried out to the field, the 
farmer then normally will prepare an aqueous solution of the herbicide, 
and apply same to the soil or undesired plants by means of a spraying 
device. 
The solution which he prepares is normally an aqueous one where the 
herbicide is dissolved, dispersed or emulsified in the water for spraying 
purposes. Obviously, if the post-emergent herbicide does not dissolve or 
disperse well in water, it will not penetrate the plants' leaves and will 
not be taken into the system, and the herbicidal activity will be 
diminished. The tetraaluminum salt of N-phosphonomethylglycine, is 
practicaly insoluble in water and organic solvents, and thus cannot be 
effectively applied in an effective manner to the locus where it is 
desired to have control. 
DESCRIPTION OF THE INVENTION 
It has now been discovered, however, that the herbicidal activity of the 
tetraaluminum salt of N-phosphonomethylglycine can be substantially 
improved by incorporating into the composition, from 0.05 to 50% by weight 
of a polyethoxylated tallow amine surfactant having the formula 
##STR2## 
where R is tallow oil having an average of 18 carbon atoms and x+y total 
15. 
The polyethoxylated tallow amine surfactant can be incorporated into the 
herbicide composition as a single component, however it is normally 
shipped by the manufacturer thereof as a solution of the surfactant in a 
solvent such a butanol or isopropanol. Accordingly, therefore, the 
preferred compositions of this invention comprise the tetraaluminum salt 
of N-phosphonomethylglycine, the polyethoxylated tallow amine surfactant, 
and an organic solvent. 
Preferably, the solvent is present in an amount not exceeding 50% of the 
weight of the herbicide composition, and most preferably in an amount 
ranging from about 10 to about 50%. 
In the preferred compositions, the weight ratio of herbicide to surfactant 
is about 2 parts herbicide to 1 part surfactant. 
Representative formulations of the compositions of this invention are as 
follows: 
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10% tetra-N--phosphonomethylglycine aluminum salt 
5% Frigate .RTM. (a solution of 70% polyethoxylated tallow 
amine and 30% butanol) 
85% water 
Total 100% 
10% tetra-N--phosphonomethylglycine aluminum salt 
5% Ethomeen C/25 .RTM. (a solution of 75% polyethoxylated 
tallow amine and 25% isopropanol) 
85% Water 
Total 100% 
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It is not known exactly how the polyethoxylated tallow amine works to 
enhance the herbicidal activity of the tetraaluminum salts of 
N-phosphonomethylglycine. However, it is believed that with increased 
solubility, the active herbicide is able to penetrate plant surfaces to a 
substantially greater extent that had been the case previously. 
Practically any organic solvent can be used as a part of the composition. 
Suitable solvents include butanol, dimethylformamide, etc. 
The compositions of this invention are made by simply mixing the herbicide 
with the organic solvent and the surfactant in any suitable container. 
Normally, the surfactant and solvent will come as a solution from the 
manufacturer. 
The tetraaluminum salt of phosphonomethylglycine can be produced by 
reacting N-phosphonomethylglycine with aluminum in the presence of water 
in accordance with the method described in co-pending application Ser. No. 
442,067, filed Nov. 16, 1982, now abandoned. 
The preferred polyethoxylated tallow amine is sold by the Diamond Shamrock 
Corporation, Dallas, Tex., under the trade name Frigate.RTM.. This is a 
mixture of 70% amine in 30% butanol. Similar compounds are sold under the 
trade names Ethomeen C/25.RTM. by Armak Industries, Chemical Division, 
Chicago, Ill. 
The enhanced herbicidal activity of the compounds of the invention is 
exhibited by means of tests in accordance with the following procedure.

EXAMPLE 1 
Herbicidal Activity Tests 
This example offers herbicidal activity test data to show the effectiveness 
of the tetraaluminum salt of N-phosphonomethylglycine composition 
containing the polyethoxylated amine enhancer. The effect is observed by 
comparing the extent of weed control in test containers treated with the 
salt plus enhancer against that occuring in similar control containers 
treated with the salt alone. The soil used in these tests was a sandy loam 
soil from the Livermore, California area. 
Also added to the soil was 17-17-17 fertilizer (N-P.sub.2 O.sub.5 -K.sub.2 
O on a weight basis), amounting to 50 ppm by weight with respect to the 
soil, and CAPTAN, a soil fungicide. 
The treated soil was then placed in plastic tubs, 6 inches in diameter and 
5 inches deep with drainage holes. Johnsongrass rhizomes, Bermuda grass 
cuttings, and purple nutsedge tubers were planted. The test weeds were as 
follows: 
______________________________________ 
COMMON NAME SCIENTIFIC NAME 
______________________________________ 
Grasses: 
A. johnson grass Sorghum halepense 
B. bermuda grass Cynodon dactylon 
C. purple nutsedge Cyperus rotundus 
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Sufficient stock or cuttings were planted to produce several seedlings per 
tub. After planting, the tubs were then placed in a greenhouse maintained 
at 70.degree. to 85.degree. F. (21.degree. to 30.degree. C.) and watered 
daily by sprinkler. 
Chemical application was made by spraying approximately 35 days after 
planting. 
The spray solution for Composition No. 1 in Table I below is prepared by 
mixing 0.4 g of the tetraaluminum salt of N-phosphonomethylglycine with 
39.4 g of a 50-50 acetone-water mixture plus 0.2 g Tween.RTM. 20 
(polyoxyethylene sorbitan monolaurate). 
The spray solution for Composition No. 2 in Table I below is prepared by 
dissolving 0.4 g of the tetraaluminum salt of N-phosphonomethylglycine 
plus 39.4 g of water and adding thereto 0.2 g Frigate.RTM.. 
Twenty grams (20 g) of this solution is added to 20 g of H.sub.2 O and 
sprayed at 25 gallon/acre, resulting in a 1.0 lb/acre rate of chemical 
application. Other rates were achieved by varying the solution 
concentration. 
Approximately 28 days after treatment, the degree of weed control was 
estimated and recorded as percentage control compared to the growth of the 
same species in an untreated check tubs of the same age. The rating scale 
ranges from 0 to 100%, where 0 equals no effect with plant growth equal to 
the untreated control, and 100 equals complete kill. 
The results are listed in Table I below. It is clear that the compositions 
of this invention have enhanced activity as a consequence of the addition 
thereto of the polyethoxylated amines described herein. 
TABLE I 
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HERBICIDE TEST RESULTS 
Percent Control 
Appln. Johnsongrass 
Bermuda grass 
Purple nutsedge 
Comp. 
Rate 
Rep. 1 
Rep. 2 Rep. 1 
Rep. 2 Rep. 1 
Rep. 2 
No. (lb/A) 
A A Ave 
B B Ave 
C C Ave 
__________________________________________________________________________ 
1 0.25 
0 20 10 0 0 0 -- -- -- 
(con- 
0.50 
60 81 70 40 40 40 0 10 5 
trol) 
1.00 
-- -- -- -- -- -- 40 50 45 
2 0.25 
90 100 95 80 80 80 -- -- -- 
0.50 
100 100 100 
95 95 95 80 80 80 
1.00 
-- -- -- -- -- -- 95 98 97 
__________________________________________________________________________ 
Ave = Average of two replications. 
METHODS OF APPLICATION 
The herbicidal compositions of the present invention are useful in 
controlling the growth of undesirable vegetation by pre-emergence or 
post-emergence application to the locus where control is desired, 
including pre-plant and post-plant soil incorporation as well as surface 
application. Post-emergence foliar application is preferred. The 
compositions are generally embodied in formulations suitable for 
convenient application. Typical formulations contain additional 
ingredients or diluent carriers which are either inert or active. Examples 
of such ingredients or carriers are water, organic solvents, dust 
carriers, granular carriers, surface active agents, oil and water, 
water-oil emulsions, wetting agents, dispersing agents, and emulsifying 
agents. The herbicidal formulations generally take the form of 
emulsifiable or liquid concentrates. 
Emulsifiable concentrates are usually solutions of the active materials in 
nonwater-miscible solvents together with an emulsifying agent. Prior to 
use, the concentrate is diluted with water to form a suspended emulsion of 
solvent droplets. 
Typical solvents for use in emulsifiable concentrates include weed oils, 
chlorinated hydrocarbons, and nonwater-miscible ethers, esters, and 
ketones. 
Typical emulsifying agents are anionic or nonionic surfactants, or mixtures 
of the two. Examples include long-chain alkyl or mercaptan polyethoxy 
alcohols, alkylaryl polyethoxy alcohols, sorbitan fatty acid esters, 
polyoxyethylene ethers with sorbitan fatty acid esters, polyoxyethylene 
glycol esters with fatty or rosin acids, fatty alkylol amide condensates, 
calcium and amine salts of fatty alcohol sulfates, oil soluble petroleum 
sulfonates, or preferably mixtures of these emulsifying agents. Such 
emulsifying agents will comprise from about 1 to 20 weight percent of the 
total composition. 
Thus, emulsifiable or liquid concentrates of the present invention will 
consist of from about 10 to about 50 weight percent active material, about 
40 to 85 weight percent solvent, and about 1 to 20 weight percent 
emulsifier. Other additives such as spreading agents and stickers can also 
be included. 
IN GENERAL 
Each of the above formulations can be prepared as a package containing the 
herbicide together with the other ingredients of the formulation 
(diluents, emulsifiers, surfactants, etc.). The formulations can also be 
prepared by a tank mix method, in which the ingredients are obtained 
separately and combined at the grower site. 
In general, any conventional method of application can be used. The locus 
of application can be soil, seeds, seedlings, or the actual plants, as 
well as flooded fields. Foliar application is preferred. Liquid 
compositions can be applied by the use of boom and hand sprayers. The 
compositions can also be applied from airplanes sprays because they are 
effective in very low dosages. 
The amount of the present composition which constitutes a herbicidally 
effective amount depends upon the nature of the seeds or plants to be 
controlled. The rate of application of active ingredient varies from about 
0.01 to about 50 pounds per acre, preferably about 0.1 to about 25 pounds 
per acre with the actual amount depending on the overall cost and the 
desired results. It will be readily apparent to one skilled in the art 
that compositions exhibiting lower herbicidal activity will require a 
higher dosage than more active compounds for the same degree of control.