Chemistry: fertilizers – Processes and products – Forms or conditioning
Reexamination Certificate
2002-10-07
2004-10-12
Langel, Wayne A. (Department: 1754)
Chemistry: fertilizers
Processes and products
Forms or conditioning
Reexamination Certificate
active
06802882
ABSTRACT:
The invention relates to the use of inorganic or organic polyacids for the treatment of inorganic fertilizers.
In particular, the invention relates to the use of polyacids as a mixture with at least one nitrification inhibitor for the treatment of inorganic fertilizers, the use of selected pyrazole derivatives as nitrification inhibitor in inorganic fertilizers, and as stabilizers of liquid manure or liquid fertilizer formulations, and the corresponding treated inorganic fertilizers per se. Moreover, the present invention relates to pyrazole derivatives which can be used as nitrification inhibitors in inorganic fertilizers, and as stabilizers of liquid manure or liquid fertilizer formulations.
In order to make available to plants in agriculture the nitrogen needed by them, ammonium compounds are mainly employed as fertilizers.
Ammonium compounds are converted microbially to nitrates in the soil in a relatively short time (nitrification). Nitrates, however, can be washed out of the soil. The portion washed out is in this case no longer available for plant nutrition, so that for this reason rapid nitrification is undesirable. For better utilization of the fertilizer, nitrification inhibitors are therefore added to the fertilizer. A known group of nitrification inhibitors are pyrazole compounds.
A problem in the use of pyrazole compounds as nitrification inhibitors is their high volatility. During the storage of fertilizer preparations containing pyrazole compounds, a continuous loss of active compound occurs due to evaporation. The pyrazole compounds must therefore be formulated in a nonvolatile form by means of suitable measures.
To fix the pyrazole compounds, these were converted, for example, into transition metal complexes such as zinc complexes. This is described, for example, in U.S. Pat. No. 4,522,642. The volatility of the active compounds can thus be reduced. For environmental protection reasons, the widespread application of zinc, copper or manganese to the soil is, however, undesirable. Complexes of alkali metals or alkaline earth metals which are environmentally tolerable, are not adequately stable, however, and hydrolyze in the aqueous environment.
It has furthermore been attempted by neutralization of the pyrazole compounds with mineral acids, such as phosphoric acid or hydrochloric acid, to decrease their volatility. DE-A-4 128 828 describes the use of nitrates and phosphates of 3-methylpyrazole for the coating of fertilizers. U.S. Pat. No. 3,635,690 also describes the stabilization of pyrazole derivatives by mineral acids, such as hydrochloric acid, sulfuric acid, nitric acid and phosphoric acid. These acidic salts of the pyrazole compounds, however, are increasingly susceptible to hydrolysis and for this reason cannot be employed for all applications.
DE-A-4 128 828 further describes the sealing of the coated fertilizer with wax or oil. In the case of hygroscopic active compound salts, however, this process does not lead to a satisfactory resistance to hydrolysis.
Formulations of pyrazoles with polymeric auxiliaries have furthermore been employed. Thus DE 260 486 describes formulations of pyrazoles in urea-formaldehyde condensates. The incorporation of the active compounds into the polymer matrix, however, suppresses the mobility of the active compounds in the soil. In this application form, therefore, the finely divided formulation and fertilizer must be thoroughly mixed with the soil to be fertilized. Otherwise the nitrification inhibitor remains on the surface of the earth with the polymer matrix. The need to mix formulation, fertilizer and soil, however, is laborious.
It is an object of the present invention to provide inorganic fertilizers which contain a nitrification inhibitor whose content does not significantly change during storage and application of the fertilizer, and which remains in the ground after application of the fertilizer and can display its action there. Furthermore, new nitrification inhibitors shall be provided.
We have found that this object is achieved by use of inorganic or organic polyacids for the treatment of inorganic fertilizers. In this case, the treated inorganic fertilizer contains a nitrification inhibitor which is present in the inorganic fertilizer or on its surface. The nitrification inhibitor can furthermore also be employed as a mixture with the polyacid and then passes into this during the treatment of the inorganic fertilizer employed according to the invention, preferably onto the surface thereof.
The use of inorganic or organic polyacids for the treatment of inorganic fertilizers which contain nitrification inhibitors leads to an improved fixation of the nitrification inhibitors in the inorganic fertilizer. The volatility of the nitrification inhibitor is greatly reduced in this case, so that the storage stability of the treated inorganic fertilizer increases. Loss of nitrification inhibitor during a storage period or on application to the soil is avoided.
In addition, the treatment according to the invention and the treated inorganic fertilizer thus obtained have the advantage of ecological acceptability. They contain no toxic substances, such as, for example, zinc, copper or manganese, which in relatively large amounts very severely restrict environmental tolerability and can lead to soil contamination.
The treatment according to the invention can furthermore be carried out in a cost-efficient and ecologically tolerable manner. As a result of the treatment according to the invention, the amount of nitrification inhibitors in the inorganic fertilizer can be reduced because of the decreased volatility, which leads to decreased costs and to a better environmental tolerability of the fertilizers according to the invention. The object is furthermore achieved by the use of compounds of the general formula
where the radical R
1
is a hydrogen atom, a halogen atom or a C
1-4
-alkyl radical, the radical R
2
is a C
1-4
-alkyl radical and the radical R
3
is H or a radical —CH
2
OH, where if R
3
is H the salt of the compounds with phosphoric acid can also be employed, as nitrification inhibitors. Preferably the compound used is 3,4-dimethyl pyrazole, 4-chloro-3-methylpyrazole or a phosphoric acid addition solt thereof.
Polyacids
According to the invention, inorganic or organic polyacids are used for the treatment of the inorganic fertilizers.
In this case, all suitable inorganic or organic polyacids can be used which decrease the tendency of nitrification inhibitors to evaporate.
Inorganic polyacids which can be used according to the invention are isopolyacids or heteropolyacids, in particular polyphosphoric acids or polycyclic acids. The polyphosphoric acids, for example, have the general formula H
n+2
P
n
O
3n+1
, n being an integer of at least 2, preferably at least 10.
Further inorganic polyacids which can be used are known to the person skilled in the art.
Suitable organic polyacids are those polymers which have a plurality of free carboxylic acid groups. These can be homo- or copolymers. Suitable monomers containing carboxyl groups or carboxylic acid groups are, in particular, monoethylenically unsaturated mono- or dicarboxylic acids having from 3 to 6 C atoms or their corresponding anhydrides, such as, for example, acrylic acid, methacrylic acid, ethylacrylic acid, allylacetic acid, crotonic acid, vinylacetic acid, maleic acid, itaconic acid, mesaconic acid, fumaric acid, citraconic acid, methylenemalonic acid, as well as their esters, such as, for example, monoalkyl maleates, and mixtures thereof. In the case of monoalkyl dicarboxylates, the number of C atoms specified relates to the dicarboxylic acid structure, the alkyl group in the ester radical, independently thereof, can have from 1 to 20 C atoms, in particular from 1 to 8 C atoms. Suitable appropriate monoethylenically unsaturated dicarboxylic anhydrides are maleic anhydride, itaconic anhydride, citraconic anhydride and mixtures thereof. Acrylic acid, methacrylic acid, maleic acid, itaconic acid and maleic anhydride are preferably employed. Acrylic
Barth Thomas
Dressel Jürgen
Erhardt Klaus
Gold Randall Evan
Leibold Edgar
BASF - Aktiengesellschaft
Keil & Weinkauf
Langel Wayne A.
LandOfFree
Nitrification inhibitors, and the use of polyacids which... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Nitrification inhibitors, and the use of polyacids which..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Nitrification inhibitors, and the use of polyacids which... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3323726