US2861091A

US2861091A - Manganous dimethyldithiocarbamate stabilized with zinc dimethyldithiocarbamate

Info

Publication number: US2861091A
Application number: US650826A
Authority: US
Inventors: Jr Robert O Beauchamp; Thomas P Johnston
Original assignee: TENNESSE CORP
Current assignee: TENNESSE Corp
Priority date: 1957-04-05
Filing date: 1957-04-05
Publication date: 1958-11-18
Anticipated expiration: 1975-11-18

Description

MANGANOUS DIMETHYLDITHIOCARBAMATE STABTLIZED WITH ZINC DI METHYLDITHIO- CAAMATE No Drawing. Application April 5, 1957 Serial No. 650,826

7 Claims. (Cl. 260-429) This invention relates to mixtures of manganous and zinc dimethyldithiocarbamates in which the manganous dimethyldithiocarbamate is stabilized against spontaneous combustion and deterioration and to processes for preparing such stabilized mixtures.

The fungicidal properties of manganous dimethyldithiocarbamate are known to the art and the inherent instability of manganous dimethyldithiocarbamate has been recognized as in the U. S. Patent to Flenner No. 2,504,404. Johnson Patent No. 2,665,285 describes the stabilization of manganous dimethyldithiocarbamate by the use of an added stabilizer such as suitable sulfites.

The value of manganous dimethyldithiocarbamate as a fungicide and its inherent instability are also recognized in the Bradley Patent No.-2,765,327 where Bradley proposes to remove the inherent instability of the manganous dimethyldithiocarbamate by washing a precipiie States Patent() tate thereof in the absence of air to remove water soluble V salts. I

It is therefore well established that manganous dimethyldithiocarbamate is effective as a fungicide but is impractical and inherently hazardous because itis subject to spontaneous combustion and to deterioration on storage Most unexpectedly we have found that intimate mixtures of manganous dimethyldithiocarbamate with substantial amounts of zinc dimethyldithiocarbamate stabilize the manganous dimethyldithiocarbamate"against spontaneous combustion and deterioration without deleterious effects on its fungicidal activity., We have further found that such mixtures can be driedsafely and stored at elevated temperatures without the he hazards involved in present manufacture, storage and use of manganous dimethyldithiocarbamate;

It is therefore an object of the present invention to provide mixtures of manganous and zinc dimethyldithiocarbamates which are stable and in which the manganous,

dimethyldithiocarbamate is not subject to spontaneous combustion or to deteriorati on, such mixtures havingno,

deleterious effectson the fungicidal activity of the man-. ganous dimethyldithiocarbamate.

Another object of the preselit invention is to provide novel processes for obtaining intimate mixtures of manganous and zinc dirnethyldithiocarbamates in which substantial amounts of zinc dimethyldithiocarbamate are present.

Other and further objects of the present invention will appear from the following description of illustrative embodiments thereof.

The procedures of the present invention and the prod ucts thereof are capable of various modifications within the scope of the present inventive concept and reference should therefore be had to the appended claims to determine the scope of this invention.

As noted above, varying amounts of zinc dimethyldithiocarbamate may be mixed with the manganous dimethyldithiocarbamate to stabilize the manganous dimethyldithiocarbamate against spontaneous combustion and deterioration. Mixtures containing less-hthan'-; 50:%Y

zinc dimethyldithiocarbamate may come within the present concept and mixtures containing at least about 50%, of zinc dimethyldithiocarbamate have been found tomeet; the objectives of the present invention, Such mixtures of manganous and zinc dimethyldithiocarbamates can be dried and stored safely at elevated temperatures without 1 deleterious effects on fungicidal activity and without il'l6'-;

known hazards of spontaneous combustion inherent-in the handling of manganous dimethyldithiocarbamate. Mixtures of manganous and zinc dimethyldithiocar-,;- bamates can be prepared in various ways as by intimately dry-mixing the two salts in any suitable manner. Since such dry-mixing of the two salts entails drying;unstabilized manganous dimethyldithiocarbamate before mix- 1 ing with its inherent difliculties mentioned above; how ever, we prefer to prepare the stabilized mixtureof man-; ganous and zinc dimethyldithiocarbamates by co-precipia-v tation of manganousdimethyldithiocarbamate and"zinc..;. dimethyldithiocarbamate by processes utilizing thereaction in aqueous solution of desired ratios of inorganic water-soluble manganous and zinc salts with an alkali metal or alkaline earth metal dimethyldithiocarbamate;' The resulting precipitate is an intimate, stable mixture of manganous and zinc dimethyldithiocarbamates which remains stable upon drying and storing. I

A stable mixture of manganous and zinc dimethyldithiocarbamate's is obtained in the process generally. del scribed above when the ratio of zinc to manganous saltsv is such as to give substantial amounts of zinc dimethyldithiocarbamate in the mixture and may be at ,least-= about one to one. a

The precipitate of such a process may be dried. conventional methods utilizing tray-drying at 140 F. or flash-drying at 190 F. without combustion or darkening comparable to that of the manganese salt alone of'the precipitate. These precipitates have beenstored in'bulk for extended periods at temperatures up to 135 and striking differences were obtained in'the'dryijngand storage properties of the manganous dimethyldithiocarbamate. Manganous dimethyldithiocarbamate I alone' when tray-dried at 120 F. darkened appreciably and ignited spontaneously when stored in bulk at 120? Mixtures of manganous and zinc; dimethyldithiocarbamates of the present invention have exhibited no loss 'in fungicidal activity when'subjected to storage 'in bulk at elevated temperatures as high as 135 FffThe fu'ng toxicity of these mixtures when stored'in bulk "at elevated temperatures for long periods of time was determined by As noted above the procedures of the present invention and the products thereof are capable of various modifications all within the scope of the present inventive concept. In a typical process resulting in a stabilized mixture of manganous and zinc dimethyldithiocarbamates having stability against spontaneous com bustion and the ability to remain in storage for long periods of time at high temperatures without loss of fungitoxicity, 350 pounds of a 7.16% aqueous solution of sodium hydroxide at about F. was employed to which was added 70.5 pounds of a 40% aqueous solution of dimethylamine and the mixed solutions were agitated. A total of fifty pounds of carbon bisulfide was then added slowly with agitation over a period of about 30 to 35 minutes maintaining the temperature of the solution below F. A solution of sodium dimethyldithiocarbamate was formed having a pH of 8.5-9.0. T9

Patented Nov. 18,1958- this solution ofsodium dimethyldithiocarbamate 181 pounds ofa solution containing 24.88 pounds of MnSO, and 25.48 pounds of ZnSO were added rapidly with agitation. A mixture of manganous and zinc dimethyldithioearbamatesprecipitated in this solution and was removed by filtration'on a plate 'and frame filter press. The filtered mixture was washed with water and traydried in anoven at 135 F. The dried material was then pulverized and was of a light tan to green color. Fifty pounds of the tray-dried material was then stored in a fiber drum at 13ll33 F. for 29 days without evidence of decomposition or loss of fungitoxicity.

In another example of a process and product in accordance with the present invention, 350 pounds of 7.16% aqueous solution of sodium hydroxide at about 75 F. was employed to which was added 70.5 pounds of a 40% aqueous solution of dirnethylamine with agitation. Fifty pounds of carbon bisulfide was then; added slowly with agitation to this solution over a period of about 30 to 35' minutes maintaining the temperature below 85 F. A solution of sodium dimethyldithiocarbamate was formed having a pH of 8.5 to 9.0. To this solution ofi'sodium dimethyldithioearbamate was then added rapidly w-ith agitation 198.5 pounds of; a solution containing 14.95- pounds of MnSO and 34.86 pounds of'ZnSO A mixture of manganous and zinc dimethyldithiocarbamates precipitated and was removed by filtration on; a plate and frame filter 'press, the mixture was washed with water, was tray-dried at 1 35 "-'.F., and the dried material was pulverized and was of a light tan to green color. Fifty'pounds of the tray-dried material was then stored in a'fib'er drum at 135- F.'f orfourteen days without evidence or decomposition or loss of fungitoxicity.

The dithiocarbamate mixture containing 70% Zn salt gave the following percentage spore germination of M onilinia fructicola (M) and Curvularz'a lunata (C) before andafter' storage at 135 F. for 14 days:

etor M: 32 p. p.'m., 29%; 63. pap. m., 0% C: 63p. p. 111., 99%; 125 p. p. m, 2% After-..

I M; 32 p. p. m., 13%; 63 p. p. m., 0%

C: 63 p. p.'m 91%; .,25fpfp. 1:1,, 0%

The dithiocarbamate mixture containing 50% zinc salt gave the following percentage spore germination of Carvularia lunata (C) before and after storage at 131-133 F. for twenty-nine days: 1

fore-C: .6.1 n 6. 32 pp 3%; 6

.,;'0% A ter'C= 35 pm- 2 pp.

carbamates stabilized against spontaneous combustionand. deterioration have been obtained when the percentage of zinc Salts present was at least about 50% but lesser 4 amounts of the zinc salts will secure the desired stabilization of the manganous dimethyldithiocarbamate depending upon the conditions under which the co-precipitated mixtures of manganous and zinc dimethyldithiocarbamates are obtained or used.

It should now be apparent to those skilled in the art that the present invention in every way satisfies the several objectives discussed above.

Changes in the above described illustrative procedures and in the composition of the mixtures of manganous and Zinc dimethyldithiocarbamates may now be suggested to those skilled in the art Without departing from the present inventive concept. Reference should therefore be had to the appended claims; to determine the scope of this invention.

What is claimed is:

l. A co-precipitated intimates mixture of manganous and zinc dimethyldithiocarbamates containing from about 50% to zinc dimethyldithiocarbamate having stability against spontaneous combustion, deterioration, and loss of fungitoxicity.

2. A mixture of Zinc and manganous dimethyldithiocarbamates containing from about 50% to 70% zinc dimethyldithiocarbamate having stability against spontaneous combustion, deterioration, and loss of fungitoxicity.

3. In a process for stabilizing manganous dimethyldithiocarbamate against spontaneous combustion, deterioration, and loss of fungitoxicity, the steps of mixing an aqueous solution of inorganic soluble manganous and zinc salts and an aqueous solution of a chemical compound selected from the group consisting of alkali metal dimethyldithiocarbam'ates and alkaline earth dimethyldithiocarbamates until a slurry is obtained, filtering the slurry to remove precipitated manganous and Zinc dimethyldithiocarbamates, washing the precipitated manganous and zinc dimethyldithiocarb'amates with water, and then drying the manganous and zinc dimethyldithiocarbamatcs.

4. A process as described in claim 3 in which the organic water-soluble salts are manganoussulfate and zinc sulfate.

5. A process as described in claim 3 in which the soluble dimethyldithiocarbamate is sodium dimethyldithiocarbamate.

6. A process as described in claim 3, in which the manganous and zinc dimethyldithiocarbamates are traydried at approximately 135-l40 F.

7. A process as described in claim 3 in which the manganous and zinc dimethyldithiocarbamates are flash-dried at approximately 1 F.

References Cited inthe file of this patent UNITED STATES PATENTS 2,406,960 Neal et al Sept. 3, 1946 2,504,404 Flenner Apr. 18, 1950 2,665,285 Johnson Jan. 5, 1954 2,765,254 Somerville Oct. 2, 1956

Claims

1. A CO-PRECIPITATED INTIMATES MIXTURES OF MANGANOUS AND ZINC DIMETHYLDITHIOCARBOMATES CONTAINING FROM ABOUT 50% TO 70% ZINC DIMETHYLDITHIOCARBAMATE HAVING STABILITY AGAINST SPONTANEOUS COMBUSION, DETERIORATION, AND LOSS OF FUNGITOXICITY.

3. IN A PROCESS FOR STABILIZING MANGANOUS DIMETHYLDITHIOCARBONAMATE AGAINST SPONTANEOUS COMBUSTION, DETERIORATION, AND LOSS OF FUNGITOXICITY, THE STEPS OF MIXING AN AQUEOUS SOLUTION OF INORGANIC SOLUBLE MANGANOUS AND ZINC SALTS AND AN AQUEOUS SOLUTION OF A CHEMICAL COMPOUND SELECTED FROM THE GROUP CONSISTING OF ALKALI METAL DIMETHYLDITHIOCARBAMATES AND ALKALINE EARTH DIMETHYLDITHIOCARBAMATES UNTIL A SLURRY IS OBTAINED, FILTERING THE SLURRY TO REMOVE PRECIPITATED MANGANOUS AND ZINC DIMETHYLDITHIOCARBAMATES, WASHING THE PRECIPITATED MANGANOUS AND ZINC DIMETHYLDITHIOCARBAMATES WITH WATER, AND THEN DRYING THE MANGANOUS AND ZINC DIMETHYLDITHIOCARBAMATES.