CA1082723A - Noncorrosive cuprammonia fungicide and method for using - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
A substantially noncorrosive solution of cuprammonia low carboxylate complex of copper carboxylate and ammonium carboxy-late is described wherein said complex is fungicidally and bactericidally effective when diluted with water in an amount of 3 to 200 parts of water per part of complex solution. The dilution causes the hydrolysis of the complex and the precipi-tation of a finely divided flocculent form of fungicidally and bactericidally active copper values. When the flocculent precipitate is applied to the locus of bacteria or vegetation on which fungus is to be controlled, the flocculent precipitate forms a gelatinous coating of copper values which adhere teneciously to the locus of application or vegetation where applied. Once dried, the coating adheres as a coating which is not readily removed by moisture or rainfall.

Description

108~7i~3 INTRODUCTION
This invention relates to fungicides and more particularly to cuprammonia low carboxylate compositions which are made sub-stantially noncorrosive in a liquid concentrate form and which, when diluted with water, hydrolyze to bactericidally and fungi-cidally active materials. The hydrolized product formed there-from, when applied to the locus of a fungus or bacteria to be controlled, effectively controls said fungus or bacteria.

BACKGROUND OF THE INVENTION
It is well-known that fungi are a large group of nongreen plants that receive their energy and raw materials through para-sitic habits. Fungi are dependent upon the organic food made by photosynthesizing green plants. They represent a constant and ever present threat to many agricultural crops ranging from tropi-lS caland semi-tropical vegetation to temperate climate crops. The control of fungi has been achieved through the use of a hetero-geneous group of chemicals termed "fungicides~ that mitigate, in-hibit or destroy fungi. Such fungicides have been applied by spray or dust applications of protective or eradicative amounts of the material to the locus of the fungi to be controlled.
The bacteria, also, form a well-known class of microscopic plants having round, rod-like, spiral or filamentous single-celled or non-cellular bodies which are often aggregated into colonies or motile by means of flagella. Bacteria live in soil, water, or organic matter, in the bodies of plants and animals, and are autotrophic, saprophytic, or parasitic in nutrition. Bacteria can be either helpful or harmful to man~ind and are often used by man to his advantage. It is often desirable and necessary to control bacteria to prevent damage to organic matter. As such, bactericides perform a valuable function in the control or eradi-108;~7~3 cation of unwanted bacteria.
The compositions of this invention are particularly valuableas bactericides when applied to the locus of bacteria to be con-trolled in an effective amount. The method and amount of compo-sition applied to effect bacteri~i~l control is similar to thefungicidal method and amount. Consequently, the presented in-vention will be described more particularily with respect to the fungicidal use because such use has been more extensively investi-gated and is the preferred use. This, however, is not to in any manner limit the scope of the present invention, but rather is a manner of more clearly setting forth the preferred embodiments of the present invention.
Prior to about 1939, inorganic sulfur and copper compounds were used almost exclusively as sprays and dust fungicides. Cop-per and mercury compounds were also used as applications in seedtreatments. As early as 1882, copper sprays were introduced as a Bordeaux mixture for the control of do~my mildew on grapes. The Bordeaux mixture consisted of a light blue gelatinous precipitate suspended in water and formed by reacting 4 parts of copper sulfate to 4 parts of hydrated lime (calcium hydroxide) in 50 gallons of water. Various variations in the composition of the resulting mixture have been made by changing the ratio of the components.
While copper co~pounds have been known for their ability to control fungi, soluble copper compounds are known to be extremely toxic to vegetation. Consequently, the copper materials applied must be relatively non-toxic to the plants while being effective fungicides. As such, it is necessary, in order to have an effec-tive fungicide, to have an insoluble copper material in finely divided form which can be effectively applied to vegetation in a 3~ manner whereby it will adhere to the vegetation while remaining non-toxic to the vegetation to which it is applied. The finer ~08~7Z3 the copper compound, the more surface area it can cover and there-fore, in general, the more effective it will be per unit weight.
It is well-known that various materials, including copper compounds, can be milled to extremely fine particle size such that the surface area of the particle becomes extremely large. With finely milled material, theoretically such material is able to cover massive surface areas with relatively small amounts of copper compound. As a practical matter, it is extremely difficult to disperse and/or redisperse such finely milled co~er materials be-L0 cause of the tendency of fine particles to agglomerate such thatthe finely divided particles are not fully dispersed but rather accumulate as larger particles, thus greatly reducing the effec-tiveness and surface area of the material.
It has been discovered that an effective way of producing L5 the required finely divided dispersant of copper values is to pre- -cipitate the copper values in situ. Under certain desirable con-ditions, copper can be made to precipitate in the desired finely divided state. However, it is also well-known that the more de-sirable copper solutions are corrosive, particularly visa brass For example, copper chloride is used as an etchant. Cuprammonia is known to be a much more powerful corrosive than either copper or ammonium ions individually. With the corrosive nature of copper solutions, it is particularly parenthetical that brass is the most widely used material for fungicidal spraying equipment, particularly the pumps, valves and nozzles used in such equipment.
This corrosiveness is well docum~by Rumford, Chemical Engineer-ing Materials, 1st American Edition, pp. 194.
If the ammonia in a spray-type cuprammonia fungicide solution is bound by simply changing the pH, then as the pH of 7 is approached on the alkaline side, the copper q~antitatively turns to an insolu-ble form ~hich settles to the bottom of the storage containers. On the other hand, if the copper is prevented from precipitating with chelating agents such as EDTA (ethylene diamino tetra ~ :
acetate), it will not deposit the active adherent form of copper required to protect the vegetation.
In accordance with the invention, there is provided a substantially noncorrosive concentrate solution which is hydrolyzable to a fungicidal composition comprising an aqueous cuprammonium lower carboxylate complex of coppèr lower carboxy-late and ammonium lower carboxylate in weight proportions of about 13 parts of copper lower carboxylate as measured as the dihydrate to about 2 parts of ammonium lower carboxylate and ~

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. ~ . .

108~7~3 . .
about 10 parts of 29 percent aqueous ammonia, said solution being at a pH in the range of about 7.1 to 7.4, said concentrate being diluted with water in an amount not exceeding about 50 parts by weight.
The low carboxylate is selected from the group consisting of formate, acetate and propionate, with acetate being the most preferred carboxylate.
The present composition effectively eliminates , suppresses, retards, reduces, or otherwise controls the activity of a wide variety of fungi and bacteria.
The composition can be applied as a dilute spray or concen-trate spray either in ground applications or aerial applications.
The composition can be used alone or in conjunction with insecti-cides, miticides, or other fungicides as well as extenders, sur-factants, spreaders, stickers, or oils including colloidal and non-ionic materials.
DETAILS OF TI~E INVENTION
The composition of the present invention is produced by react-ing specific amounts of copper, ammonium low carboxylate, and aqueous ~29%) ammonia so as to produce a complex having a pH in the range of about 7.1 to about 7.4 and a copper content of about 8.0 to approximately 8.20 percent~ In place of acetate, the cor-responding formate or propionate can be substituted in correspond-ing proportions to produce a complex of comparable copper content and pH range. Because the most preferred carboxylate is acetate, the invention will be more fully described with reference to ace-tate, while it should be recognized that formate and/or propion-ate can be substituted for the acetate in similar proportions to proauce correspondingly good results. Consequently, because the ~ ;
preferred mode of invention iswith acetate, the description will be described hereinaft~er more particularly with respect to the acetate embodiment.

108~7'~3 The composition of the present invention can be produced by several methods. One method is the utilization of metallic cop-per, ammonium hydroxide, or anhydrous ammonia, acetic acid and water reacted at a basic pH at elevated temperatures with the addition of oxygen or air. The complex can be produced by reacting the prerequisite amounts of copper, ammonia and acetic acid below reflux at a pH in excess of 7 and preferably 8 or more, subsequently adjusting the pH to the desired range of 7.1 to 7.4 by raising temperature to reflux and evaporating ammonia from the reaction solution. Alternatively, rather than using metallic copper, copper oxide can be substituted.
This latter method is not as suitable for the production of the corresponding propionate complex because copper oxide tends to form upon refluxing of such complex. The noted method, how-ever, is quite acceptable and desirable for the production ofeither the corresponding formate or acetate complex.
Alternatively, a particularly desirable method of forming the complex is by direct reaction of copper acetate, ammonium acetate in aqueous ammonia. Typically, 132 parts of copper ace-tate in the dehydrate form are reacted in a solution of 220 partswater and 100 parts of aqueous ammonia (29~ NH3) and 20 parts of ammonium acetate. The resulting mixture is reacted at room temperature up to the reflux temperature to produce a cuprammonia acetate complex having a pH in the range of 7.1 to 7.4 and a copper content of about 8.0 to 8.2 percent.
The amount of water used in the concentrate solution must be within certain preferred limits because an excess of water will result in the hydrolysis of the copper values to precipi-tate them from solution as described herein and to thereby form the fungicidally active material. Consequently, the amount of water used will be that which is sufficient to form the concen-trate solution complex but insufficient to hydrolysis the -~08'~7'~3 complex. The most preferred amount of waters is 22 parts by weight based on 13 parts of copper carboxylate dihydrate, 2 parts of ammonium carboxylate and 10 parts of 29~ aqueous ammonia. This amount of water can be varied,depending on the carboxylate,from as little as about 10 parts to up to about 50 parts by weight, which represents a solution containing from about 40% water to about 75% water with about 55% water being the most preferred. Larger percentages of water will result in hydrolysis as described herein.
The resulting preferred complex has a specific gravity within the range of 1.155 to 1.166, the variability being dictated by the exact amount of copper values and the inerts which might be present. Greater or lesser amounts of water will also change the specific gravity.
It should be noted that acetic acid or acetates in conjunc-tion with copper are not ordinarily considered solublizing (che-lating) agents for copper. To the contrary, the presence of acetic acid or acetates is considered to lower the solubility of copper salts. Illustratively, the nitrates, chlorides, and sulfates of copper all have solubilities several times that of copper acetate. In addition to making copper soluble at pH con-ditions where it would normally be precipitated, the reaction product retains the desired precipitate characteristics found in cuprammonia complexes. This is accomplished by depositing a hydroxide form of copper rather than a basic acetate when the copper acetate solution is diluted.
Attempts to structurally determine the reaction products of the present invention by the usual analytic chemical techniques of functional group analysis, degradative structural analysis and the separation and identification of residues has been in-conclusive. It is believedthat the reaction product is a cupra-mmonia acetate complex having the mono-molecular form Cu(NH3)2 ~0~'~7;~3 (O-CO.C~3)2. ~ile applicant does not wish to be bound by any particular theory, it is believed that the composition is best identified by the proportions of copper, ammonia,acetate and pH
of the solution.
The complex of the present invention is considered to be a concentrate which retains its clear solution characteristics.
For fungicidal or bactericidal used, ~he complex of the present invention is hydrolized by diluting the complex with water in the amount of about 3 to 200 parts of water per part of com-plex solution. The water dilution hydrolizes the complex, thereby forming a copper hydroxide precipitate which has the particularly desirab~e property of forming a finely dispersed flocculent material which remains suspended in solution with a very slow settling tendency. This flocculent precipitate of finely divided copper values is readily applied to the locus of fungi or bacteria to be controlled such as by spraying the area to be treated. The applied hydrolized precipitate forms a tough gelatinous film on vegetation, plants,leaves, etc. Once this film dries, it adheres tenaciously to the substrate to ~hibh it was applied and is not readily re-moved by the action of rain, dew, or other atmospheric moisture.
The gelatinous nature of this hydrolized complex makes itparticularly useful in conjunction with other chemicals which otherwise do not readily lend themselves to durable applications to vegetation. For instance, materials of low water solubility such as sulfur and lime can be made to adhere to vegetation in dis-persed form by the binding effect of the present material.
The composition of the present invention can additionally be mixed with various other fungicidal, herhicidal, insecticidal, bactericidal~ or inert materials which are desirably applied along with the present material. For instance, finely divided sulfur, lime, fillers, or inerts can be mixed with the present composition.

~urther, various other fungicides form compatible mixtures and/or synergists with the present composition.

_g_ 108;~723 It is frequently desirable to add insecticides, miticides, or herbicides in the same spraying application. Such composi-tions, for the most part, are compatible with the present com-position. Typical examples of such materials which can be mixed and applied with the present invention include chlorobenzilates, and composition sold under the trade names of Benlate 50W*;
Bravo W-75*; Captan 50-W*; Cygon 267*; Diazinon*; Difolatan 4 Flowable*; DiSyston 4EC*; Dithane M-45*; Dursban Insecticide*;
Ethion 4E*; Guthion*; Kelthane MF*; Lannate-L*; Malathion EC*;
Manzate 200*; Methyl & Ethyl Parathion EC*; Phosdrin 4 ED*;
Plictran Miticide*; Sevimol 4*; Sevin 80 WP*; Systox*; Thiodan*;
Topsin-M*; Toxaphene*; Trithion 4E*; and many others.
Most non-ionic and/or colloidal surfactants, spreaders, and stickers can also be used with the present composition.
Such materials are often useful in aiding the dispersal of other-wise difficult to disperse additives which might be desirably mixed with the present invention in simultaneous applications.
The rate of application depends upon the particular plant being treated and the fungus against which protection is desired.
The concentrate is preferably diluted in the amount of 3 to 100 parts of water per part of complex. The dilution product is ap-plied in the amount of 2 to about 800 gallons of water per acre.
Typical of the fungus which can be controlled by the present invention when applied to the locus of the fungus to be controlled include almond brown rot, apricot brown rot, blossom rot, beans bacterial blight and halo blight, carrots early and late blight, celery early and late blight, citrus fruits melanose and greasy spot; cantaloupes, melons, cucumbers, squash, etc. powdery mildew, scab, alternaria and angular leaf spots, coffee beans, grapes anthracnose, peanuts cercospora leaf spot, peaches and nectarines *Trade Mark '~? -1 O-.

108~7'~3 blossom rot, peppers cercospora leaf spot and bacteria spot, po-tatoes early and late blight, strawberries leaf spot and scorch, sugar heets cercospora leaf spot, tomatoes early and late blight and bacterial spot, walnut blight and numerous other fungus and other fungus and bacteria.
The invention will be more readily understood by reference to the following example which illustrates certain preferred em-bodiements of the present invention and in no way are to be taken as limiting the scope of the present invention. Unless other-wise noted, all parts and percentages are by weight.Example 1 In this experiment,cuprammonia acetate and cuprammonia car-bonate were diluted and the amount of copper precipitate was measured. This illustrates the deposition control property of the composition according to this invention. At the end of this time period, the copper oontent in terms of the grams oo~per per liter left in solution and the per cent copper precipitated were meas-ured for each dilution ratio.
Cuprammonia Acetate Complex 8% Cu 20 Dilution 3:1 6:1 30:160:1 100:1 Gr Cu/Liter 16.15 6.78 0.400.15 0.038 left in sol.

~ Cu 30.39 48.91 86.6790.14 95.86 precipitated 25 Copper Ammonia Carbonate 8% Cu Dilution 3:1 6:1 30:1 60:1 100:1 Gr Cu/Liter23.76 13.10 2.9761.296 0.54 ; left in sol.

Cu 1.02 4.59 4.0017.45 43.16 30 precipitated ` 10~27Z3 Example 2 I~JO identical brass surfaces were exposed at least 48 hours in respective solutions of cuprammonia acetate and cuprammonia carbonate. The object of this test was to determine the difference, if any, in the corrosion rates of the brass as a function of ex-posure to these solutions.
It was observed that the corrosion rate of brass exposed to the acetate in terms of weight loss after 48 hours, was 0.582 grams or an absolute rate of 0.0102 inches per month. In con-10 trast, the carbonate caused a brass weight loss of 13.61 gramsat an absolute rate of 0.2417 inches per month.
Example 3 The composition of the present invention was produced by reacting at atmospheric`temperature pressure about 13 parts of 15 copper acetate dihydrate with about 2 parts of ammonium acetate in a solution of 10 parts of 29 percent aqueous ammonia and about 22 parts of water. On mixing and reacting, a slight exothermic reaction was noted. The pH of the solution was adjusted to be within the range of 7.1 to 7.4 and the copper content in the range 20 of 8.0 to 8.2 percent.
Example~ 4 In the same manner, copper ammonium formate was reacted at atmospheric temperature and pressure using the same molar propor- -tions as Example 3, but substituting ammonium formate for the 25 ammonium acetate and copper formate for copper acetate. On reacting, a slight exothermic reaction was also noted. The result-ing cuprammonium formate complex was adjusted to a pH between 7.1 and 7.4 in a copper ccntent of 8.0 to 8.2 percent.

11)8A~7Z3 Example 5 In the manner of Example 3, copper ammonium propionate com-plex was produced by reacting copper propionate at room tempera-ture and pressure with ammonium propionate in a~ueous solution with ammonia in the molar proportions of Example 3. A slight exothermic reaction was noted on mixing and reacting. The result-ing cuprammonium propionate complex was adjusted to a pH between 7.1 and 7.4 in a copper content of 8.0 to 8.2.
Example 6 Cuprammonium acetate complex of the present invention was prepared by reacting metallic copper and cxygen or air in a solution of ammonium hydroxide and acetic acid. An aqueous solution of about equal molar proportions of acetic acid and ammonium hydroxide was prepared and the pH of the solution was adjusted to between 8 and 12 by the addition of excess ammonium hydroxide. Finely divided copper was then added to equal about 8.0 to 8.2 percent by weight.

Oxygen (air) was bubbled through the solution. An exo-thermic reaction was noted. The pH of the complex solution was then adjusted to between 7.1 and 7.4 by evaporating ammonia from the complex solution.

In the same manner, anhydrous ammonia can be substituted for all or part of the ammonium hydroxide and copper oxide of 25 metallic copper and air i,n place of oxygen with correspondingly good results.
Example 7 The composition of the present invention as described more particularly in Example 3 was tested for fungicidal and bacteri-108'~7Z3 cidal activitity by treating various crops with the complex diluted with water as set forth in Table I.

Table I

% Foliar ~ Foliar Fw~s to be Amount of Infection of Infection of Increased Plant Controlled Application TreatedNbntre~ted Yield Head ~ettuoe D~ny Mildew 1 pt/A in 9.0 28.7 25 gal H2O
Cabbage Downy Mildew 1 pt/A in6.5 27.6 Cauliflower 25 gal H20 7.7 29.1 Cabbage Altervaria 1 pt/A in 18.8 37.8 Blight 25 gal H2O
Caulifl~er Altervaria 1 pt/A in 11.3 28.9 Blight 25 gal H20 15 Soybean Fungus - 2/3 gal/A
Varicus in 50 gal H20 - - 8%
Onions Rot Control 3.3 gt/ 25.0 61.5 of Dried 100 gal H2O
onions as a dip 20 Pecan Scab 3 qts/ - - 48%
100 gal The above examples illustrate but a few of the fungi controlled by the composition of the present invention when applied to the locus of the fungus to be controlled. The test results indicate that sub-stantial benefits are obtained in reducing the fungicidal activity as measured by reduction in infected foilage or increased yield as compared to the control which was untreated plants.
While the invention has been described with reference to particular preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit or scope of the invention. Consequently, the invention is not to be limited other than as set forth in the appended claims.

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Claims (11)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A substantially noncorrosive aqueous concentrate solution which is dilutable with water to a fungicide composition comprising an aqueous cuprammonium lower carboxylate complex of copper lower carboxylate and ammonium lower carboxylate in weight proportions of about 13 parts of copper lower carboxylate as measured as the dihydrate to about 2 parts of ammonium lower carboxylate, and about 10 parts of 29 percent aqueous ammonia, said solution being at a pH in the range of about 7.1 to 7.4, said concentrate being diluted with water in an amount not exceeding about 50 parts by weight.

2. The solution of claim 1 wherein the carboxylate of the complex is selected from the group consisting of formate, acetate, propionate and mixtures thereof.

3. The solution of claim 1 wherein the carboxylate of the complex is acetate.

4. The solution of claim 3 wherein the specific gravity is between 1.155 to 1.166.

5. The solution of claim 3 wherein the concentrate solution is diluted with water to a copper content of about 8 to 8.2 percent by weight.

6. A fungicidal composition containing about 3 to 200 parts of water to 1 part of the solution of claim 3, said water being present in an amount sufficient to hydrolyze the complex and to precipitate copper values from the solution.

7. A fungicidal composition containing about 3 to 200 parts of water to 1 part of the solution of claim 1, said water being present in an amount sufficient to hydrolyze the complex.

8. A method of controlling fungi and bacteria on crops which comprises applying to the loci thereof a fungicidally or bactericidally effective amount of the solution of claim 7.

9. A method for producing a substantially non-corrosive cuprammonium acetate complex comprising reacting at at-mospheric temperature and pressure copper acetate and ammonium acetate in a dilute aqueous ammonia solution at a pH between about 7.1 to 7.4, said reaction proportions being in amounts to provide an aqueous solution having a copper content of about 8 to 8.2 percent by weight.

10. The method of claim 9 wherein the copper acetate is reacted in said aqueous ammonia solution with ammonium acetate in a weight ratio of about 13 to 2 wherein the copper acetate is measured as the dihydrate.

11. The method of claim 10 wherein the complex is formed by reacting weight proportions of about 13 parts of copper acetate as measured as the dihydrate, about 2 parts of ammonium acetate, about 10 parts of 29 percent aqueous ammonia in about 22 parts of water.