EP1090060A1

EP1090060A1 - Modified polycondensates of asparaginic acid, method for the production thereof, and their use in fertilizers

Info

Publication number: EP1090060A1
Application number: EP99950348A
Authority: EP
Inventors: Bernhard Mohr; Udo Metzmann; Gunnar Schornick; Jürgen Dressel; Klaus Erhardt; Wolfgang Weigelt; Klaus Horchler Von Locquenghien; Thomas Barth; Alexander Wissemeier; Wolfram Zerulla
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 1998-05-12
Filing date: 1999-05-12
Publication date: 2001-04-11
Also published as: DE19821088A1; AU4260499A; JP2002514670A; WO1999058594A1

Abstract

The invention relates to modified polycondensates of asparaginic acid which contain 0.1 to 50 mol % of at least one pyrazole compound which is covalently or ionically bound. The invention also relates to a method for producing the modified polyasparaginic acid by the condensation of a) asparaginic acid, mixtures of asparaginic acid and compounds which can be co-condensed therewith, and by the respective condensation of alkali metal salts or ammonium salt of the asparaginic acid with b) at least one nitrification inhibitor, preferably a pyrazole compound, at temperatures ranging from 120 to 270 °C and, afterwards, the optional hydrolysis of aspartimide units, said units being formed during the condensation, into asparaginic acid units or the salts thereof using alkali metal, alkaline-earth metal or ammonium bases, or by attaching at least one pyrazole compound to polycondensates containing aspartimide units, or by mixing polycondensates of asparaginic acid with nitrification inhibitors and using the modified polycondensates of asparaginic acid obtained in this manner as nitrification inhibitors and mineral fertilizers. Said fertilizers contain the modified polycondensates of asparaginic acid as a nitrification inhibiting addition, or mixtures of nitrification inhibitor(s) for the polycondensate of asparaginic acid in a weight ratio ranging from 0.01: 1 to 10: 1.

Description

Modified polycondensates of aspartic acid, process for their preparation and their use in fertilizers

description

The invention relates to modified polycondensates of aspartic acid, processes for their preparation by condensation of aspartic acid with at least one nitrification inhibitor, preferably a pyrazole compound or by addition of at least one nitrification inhibitor, preferably a pyrazole compound to condensates containing aspartimide units or by mixing polycondensates of aspartic acid with one or more nitrification inhibitors, preferably one or more pyrazole compounds, and the use of the polycondensates of aspartic acid modified in this way as a nitrification inhibitor and as an additive to fertilizers.

Polycondensates of aspartic acid are known. For example, polyaspartic acid is produced by condensation of aspartic acid or by reaction of maleic acid and ammonia and subsequent hydrolysis of the resulting polyasparti ide. The condensation of aspartic acid can take place in the presence of mineral acids as a catalyst or by heating aspartic acid alone to temperatures of at least 180 ° C, cf. US-A-3,052,655 and US-A-5,057,597.

From DΞ-A-22 35 190 it is known to add long-chain aikylamines to polyaspartimides. The addition products are used as surfactants in detergents.

From EP-A-0 406 623 it is known to use reaction products of polyaspartimides and amino compounds as coating agents and / or retardants for pharmaceutical forms of therapeutic agents. In order to fertilize plants in agriculture, ammonium compounds are essentially added to them as fertilizers. However, ammonium compounds are microbially converted to nitrate in the soil in a relatively short time (nitrification). The nitrate formed can be washed out of the soil relatively quickly. Since the washed-out portion is no longer available for plant nutrition, rapid nitrification is undesirable. In order to utilize the nitrogen bes ^¬ contained in the fertilizer ser, is mixed with fertilizer Nitrifikationsinhi- bitoren. A known group of nitrification inhibitors are pyrazole compounds.

BESTÄΠGUNGSKDPK 2

A problem with the use of pyrazo compounds as nitrification inhibitors is the high volatility of these compounds. For this reason, the pyrazo compounds have to be converted into a non-volatile form using suitable measures. For example, it is known from US Pat. No. 4,522,642 to reduce the volatility of pyrazo compounds by converting them into transition metal complexes. Suitable complexes are, for example, zinc compounds of pyrazoles. For environmental reasons, however, the large-scale application of transition metal complexes, which contain, for example, zinc, copper or manganese as transition metal, is undesirable. Complexes of alkali metal or alkaline earth metals which are environmentally compatible, however, do not have sufficient stability and hydrolyze in the presence of water.

It is also known to reduce the volatility of pyrazo compounds by neutralizing them with mineral acids such as phosphoric acid or hydrochloric acid. For example, DE-A-41 28 828 discloses the use of nitrates and phosphates of 3-methylpyrazois for coating fertilizers. This literature also describes the sealing of the fertilizer coated in this way with waxes or oils. However, the resistance to hydrolysis of the products available in this way still leaves something to be desired.

From US-A-3 635 690 it is known to use pyrazole and pyrazole derivatives which have no more than two halogen, nitro or alkyl groups and in each case the salts of these compounds with mineral acids as nitrification inhibitors. However, the salts of the pyrazole compounds with mineral acids are still susceptible to hydrolysis and therefore cannot be used for all applications in the agricultural sector.

From DE-A-260 486 nitrification-inhibiting polymer-active substance combinations are known in which 3-methylpyrazole or 1-carbamoyl-3-methylpyrazole is molecularly dissolved, dispersed or sorbed in a solid polymer matrix. Examples of polymers mentioned are polyvinyl alcohol, maleic anhydride copolymers, carboxymethyl cellulose, starch and urea-formaldehyde condensates. The active ingredient contained in the formulations is largely protected from volatilization and hydrolysis during storage and is released to the environment in a controlled manner when used in the soil. In this type of application, however, the fine-particle formulation and the fertilizer must be thoroughly mixed with the soil to be fertilized. Otherwise the nitrification inhibitor remains with the polymer matrix on the surface of the earth. 3 marriage. However, the need to mix the formulation, fertilizer and soil is complex.

Modified polyaspartic acids are known from EP-A-0 648 241, which can be obtained by polycondensation of aspartic acid with fatty acids, polybasic carboxylic acids, anhydrides polybasic carboxylic acids, polybasic hydroxycarboxylic acids, monobasic polyhydroxycarboxylic acids, alkoxylated alcohols, alkoxylated amines, amino carbohydrates, amino sugars , Sugar carboxylic acids and / or non-proteinogenic amino acids and mixtures of the compounds mentioned. Modified polyaspartic acids are also obtained by polymerizing monoethylenically unsaturated monomers in the manner of a radical-initiated graft polymerization in the presence of polyaspartic acid.

The invention has for its object to provide new substances. Another object of the invention is to show mineral fertilizers which contain a nitrification inhibitor, the content of which does not change significantly during storage and application of the fertilizer and which remains in the soil after application of the fertilizer and can develop its effect there.

The object is achieved according to the invention with modified polycondensates of aspartic acid if these condensates 0.1 to

Contain 50 mol%, preferably 5 to 30 mol% of at least one nitrification inhibitor, preferably a pyrazole compound, bound covalently or ionically or with mixtures of nitrification inhibitor (s) to the polycondensate of aspartic acid in a weight ratio of 0.01: 1 to 10: 1 .

The modified polycondensates of aspartic acid can be obtained, for example, by polycondensation of

a) Aspartic acid, mixtures of aspartic acid and thus co-condensable compounds and in each case the alkali metal or ammonium salts of aspartic acid with

b) at least one nitrification inhibitor, preferably a pyrazole compound and

optionally subsequent hydrolysis of the aspartimide units formed during the condensation to form aspartic acid units or their salts with alkali metal, alkaline earth metal or ammonium bases. 4

Further modified polycondensates can be obtained by polymer-analogous reaction of

a) with aspartimide units containing polycondensates

b) at least one nitrification inhibitor, preferably a pyrazole compound.

The invention also relates to a method for producing modified polycondensates of aspartic acid, wherein

b) at least one nitrification inhibitor, preferably a pyrazole compound

condensed at temperatures from 120 to 270 ° C and the condensates containing aspartimide units optionally hydrolyzed to aspartic acid units or their alkali metal, alkaline earth metal or ammonium salts or added to polycondensates containing aspartimide units or at least one pyrazole compound or polycondensates containing aspartic acid units or their alkali metal inhibitor with at least one or ammonium salt inhibitor , preferably a pyrazole compound. In the condensation and in the addition of nitrification inhibitors, preferably of pyrazo compounds to condensates containing aspartimide units, z.3. in bulk or in dimethylformamide or in dimethyl sulfoxide, modified condensates are formed which contain the nitrification inhibitors or the pyrazo compounds preferably covalently bonded. If, on the other hand, the reaction of, for example, pyrazo compounds with condensates containing aspartimide units is carried out in an aqueous medium, modified polycondensates of aspartic acid are obtained which preferably contain the pyrazo compounds bonded ionically. These are mixtures which can also be obtained by mixing polycondensates containing a) aspartic acid units or their alkali metal or ammonium salts with (b) at least one nitrification inhibitor, preferably a pyrazole compound. The mixtures contain, for example, nitrification inhibitor (s) to the polycondensates of aspartic acid in a weight ratio in general from 0.01: 1 to 10: 1 and from 0.01: 1 to 5: 1, preferably 0.1: 1 to 3: 1, particularly preferably 0.2: 1 to 1.2: 1, in particular 0.3: 1 to 0.9: 1. The molar fraction of the condensed in 5

Succinimide and / or aspartic acid units (aspartate) is 50 to 99.9 mol%, preferably 70 to 95 mol%, the molar proportion of nitrification inhibitor (s) is 0.01 to 50 mol%, preferably 5 to 30 mol% .

In these mixtures, components (a) and (b) are preferably in ionically bound form. However, they can also only be obtained as a physical mixture which, however, forms ionically bound structures between the polycondensates of aspartic acid and the pyrazo compounds when used, in particular in the presence of water. Mixing components (a) and (b) can be carried out in the absence of solvents or diluents or by combining solutions, e.g. B. aqueous solutions of components (a) and (b). The solutions can be used directly. If desired, the mixtures of components (a) and b) can also be obtained from these solutions in solid form, e.g. B. as a powder, by z. B. evaporates the solvent.

The polyaspartic acid and the nitrification inhibitor can also be used separately or in two steps, each individually, for. B. be applied to the field.

Another object of the invention is the use of the modified polycondensates of aspartic acid described above as a nitrification inhibitor.

The invention also relates to mineral fertilizers which contain the modified polycondensates of aspartic acid described above as a nitrification-inhibiting additive.

The polycondensates of aspartic acid modified according to the invention contain at least one nitrification inhibitor, preferably a pyrazole compound, bound covalently or ionically. Those polycondensates which, for example, contain a pyrazole compound covalently bonded can, for example, by polycondensation of aspartic acid, mixtures of aspartic acid and thus co-condensable compounds and in each case the alkali metal, alkaline earth metal or ammonium salts of aspartic acid with at least one pyrazole compound at temperatures of, for example, 120 to 270 ° C. getting produced. In the condensation, for example 50 to 99.9, preferably 70 to 95 mol% of aspartic acid or a mixture of aspartic acid and thus co-condensable compounds are used which contain from 0.01 to 30, preferably 5 to 30 mol% of nitrification inhibitors, preferably of Pyrazo compounds are different. Suitable compounds co-condensable with aspartic acid with the exception of 6

Pyrazoi compounds are described, for example, in EP-A-0 648 241. These are, for example, fatty acids, polybasic carboxylic acids, anhydrides polybasic carboxylic acids, polybasic hydroxycarboxylic acids, monobasic polyhydroxycarboxylic acids, alcohols, alkoxylated alcohols, amines, alkoxylated amines, amino sugars, carbohydrates and / or sugar-carboxylic acids and mixtures of the compounds mentioned. It is preferred to use aspartic acid in the polycondensation and then to modify the polyaspartimides obtained with at least one nitrification inhibitor, preferably a pyrazole compound.

Component (b) includes all nitrification inhibitors such as imidiazoles, for example 5-chloro-4-methylimidazole, 1, 2, 4-triazoles, for example 1, 2, 4-triazole and 1-hydroxymethyl-2, 4-triazole , 1,3-thiazoles, for example 1,3-thiazole, pyridine derivatives, for example 2-chloro-6-richloromethylpyridine, 2 -ethynylpyridine, alkynes such as hex-3-yn-2, 5-diol and those from Biochem. ., 227 (1985), 719-725, urea derivatives or sulfonylureas, in particular those compounds which contain a pyrazole ring. Compounds of this type are known, for example, from the literature cited in the prior art, cf. US-A-3 635 690, US-A-4 522 642 and DE-A-41 28 828. Suitable pyrazo compounds are, for example, compounds of the general formula

, R ²

^

N I

R ³

where the radicals R ¹ , R ² and R ^{3 are,} independently of one another, halogen atoms, nitro groups, hydrogen atoms or C ₁ - ₂ 0 "» preferably C _{4 -4} -alkyl radicals, C ₃ - ₈ cycloalkyl radicals, Cs- ₂₀ aryl radicals or alkylaryl radicals , the latter 4 radicals can be substituted once or triple by halogen atoms and / or hydroxyl groups.

The radical R ¹ is preferably a hydrogen atom, a halogen atom or a C ₁₄ alkyl radical, the radical R ^{2 is} a C ₁ . ₄ -alkyl radical and the radical R ^{3 is} a hydrogen atom or a radical -CH ₂ OH. 7

According to a further embodiment of the invention, one of the above formula, the radical R ^{1 is} a halogen atom or -CC alkyl radical, the radical R ^{2 is} a C _-4 -alkyl radical and the radical R ^{3 is} a hydrogen atom or a radical -CH ₂ CH ₂ COOH or -CH ₂ CH (CH ₃ ) COOH.

The pyrazo compounds can be used in the basic form, as well as in the form of acid addition salts with inorganic mineral acids and organic acids. Examples of inorganic mineral acids are hydrochloric acid, phosphoric acid, sulfuric acid, preferably phosphoric acid. Examples are organic acid

Formic acid, acetic acid, as well as fatty acids. Examples of such salts are the hydrochlorides and phosphoric acid addition salts.

The pyrazo compounds can be used individually or in the form of mixtures.

The unsubstituted pyrazole, 4-bromopyrazoi, 4-chloropyrazole, 3, 4 -dibrompyrazole, 3-chloro-4-nitropyrazole, 3-methylpyrazole, 1 -nitropyrazole, 3 -nitropyrazole, 4 -nitropyrazole, 4-bromo-i- are preferred nitropyrazole, 1,4-dinitropyrazole, 5-chloro-3-methylpyrazole, 4-bromo-3-methylpyrazole, 3,5-dimethylpyrazole, 3,4-dimethyl-pyrazole, 3-methyl-1-nitropyrazole, 3-methyl - 4 -nitropyrazole, 3 -propyl-1 -nitropyrazole, 4 -chloro-1-methylpyrazole, 1-ethylpyrazole, 4 -chloro-3-methylpyrazole, N-hydroxymethyl -3, 4 -dimethylpyrazole,

N-hydroxymethyl-4-chloro-3-methylpyrazole, N-Cχ- to C ₄ -carboxylic acid or C ₂ - to C ₂ o "carboxylic acid esters substituted pyrazoles wherein the C atoms of the pyrazole ring optionally by halogen and / or Cι-C _4- alkyl and the adducts of mineral acids with the above-mentioned pyrazo compounds. Particularly preferred pyrazo compounds are 3, 4-dimethylpyrazole, 4-chloro-3-methylpyrazole, N-hydroxymethyl-3, 4-dimethyl, N-hydroxymethyl -4 - chlorine -3-methylpyrazole and the phosphoric acid addition salts of 3,4-dimethylpyrazole and 4 -chloro-3-methylpyrazole as well as the hydrochloride of 3,4-dimethylpyrazole, particularly preferred pyrazoi compounds are 3,4-dimethylpyrazole, 3-methylpyrazole 4 -Chlor -3 -methylpyrazole.

In the polycondensation of the above-mentioned components (a) and (b), polycondensates containing aspartimide units first arise as a result of water elimination. Such polycondensates are generally insoluble in water. They can be converted into a water-soluble form by hydrolysis of the aspartimide units formed during the condensation to form aspartic acid units. The hydrolysis is preferably carried out by adding bases such as alkali metal, alkaline earth metal and ammonium bases. Preferably, the hydrolysis of the aspart 8 imide units of the polycondensates with sodium hydroxide solution or ammonia in an aqueous medium at temperatures from 20 to 150 ° C, the reaction being carried out at temperatures above 100 ° C under increased pressure.

The polycondensates of aspartic acid modified according to the invention with at least one pyrazole compound can also be obtained by a polymer-analogous reaction, in which

a) with aspartimide units containing polycondensates

b) reacting at least one nitrification inhibitor, preferably a pyrazole compound.

The polyaspartimides which are suitable as starting material can be prepared by all known processes, e.g. by polycondensation of L- or DL-aspartic acid at temperatures from 190 to 270 ° C, by polycondensation of L- or DL-aspartic acid in the presence of 0.1 to 10 mol, based on 1 mol of aspartic acid, of phosphoric acid, polyphosphoric acid, phosphorous acid , hypophosphorous acid or hydrochloric acid. With amounts of at least 2 moles of phosphoric acid per mole of aspartic acid, the polycondensation of aspartic acid is carried out in the manner of a solution polycondensation, while in the presence of smaller amounts of phosphoric acid the polycondensation takes place in a coherent solid or highly viscous phase. Polyaspartic acid imide can also be prepared from the ammonium salts or amides of fumaric acid, maleic acid or malic acid by heating to temperatures up to 250 ° C. Maleic acid monoamide and the ammonium salt of maleic acid monoamide are particularly preferably obtained by reacting solid or molten maleic anhydride with gaseous ammonia in the form of a solid gas phase reaction. The polyaspartimide obtained by polycondensation of acetylaspartic acid can also be used as the starting material. The polyaspartimides usually have K values from 8 to 50 (determined according to H. Fikentscher in 1% solution in dimethylformamide at 25 ° C).

Suitable polycondensates of group (a) are also those compounds which, in addition to aspartimide units, also contain other compounds which can be co-condensed with aspartic acid. Such compounds are known for example from the above-mentioned EP-A-0 648 241. Particularly preferred co-condensable compounds are polycarboxylic acids, anhydrides mehrbasi- shear carboxylic acids, polybasic hydroxycarboxylic acids, monobasic polyhydroxycarboxylic acids, C ₄ -C 3 ₀ amines, alkoxylated amines, and Ci- C ₃ o-Alkohie. The polycondensates containing the aspartimide units 9 are reacted with at least one pyrazole compound. The reaction is carried out, for example, by dispersing the polycondensates containing aspartimide units in water and reacting with at least one pyrazole compound at from 40 to 95 ° C. The reaction can be carried out in the presence of a base, so that polycondensates with at least partially neutralized aspartic acid units are obtained.

Suitable pyrazo compounds have already been mentioned above. The pyrazo compounds used are preferably 3, 4-dimethylpyrazole, 3 -methylpyrazole, 4 -chloro-3-methylpyrazole, the phosphoric acid addition salts of the abovementioned compounds and N-hydroxymethyl-3, 4-dimethylpyrazole or N-hydroxymethyl-4- chloro-3-methylpyrazole.

Modified polycondensates which are produced by condensation of

a) Aspartic acid with

b) at least one compound from the group consisting of 3-methylpyrazole, 3, 4-dimethylpyrazole, 4-chloro-3-methylpyrazole and the phosphoric acid addition salts of these compounds are prepared.

Mixtures of polyaspartic acid and at least one nitrification inhibitor, preferably a compound from the group 3 -methylpyrazole, 3, 4-dimethylpyrazole, 4 -chloro-3-methylpyrazole and the phosphoric acid addition salts, are also preferred. The modified polycondensates of aspartic acid according to the invention, including, in particular, physical mixtures of polyaspartic acid and nitrification inhibitors, result in use in agriculture, for. B. as an additive to fertilizers, a synergistic effect with regard to the effect in plant cultivation (eg an improved plant growth or a higher chlorophyll content). The above-described polycondensates of aspartic acid modified with pyrazo compounds are used as nitrification inhibitors. Nitrification inhibitors are added to mineral fertilizers, for example, or applied to the surface of finely divided mineral fertilizers. It is also possible to use nitrification inhibitors in liquid fertilizer formulations. Mineral fertilizers are, for example, ammonium salts or fertilizers containing urea. Examples include NPK fertilizers, calcium ammonium nitrate, ammonium sulfate nitrate, ammonium sulfate or ammonium phosphate. The mineral fertilizers can be in the form of a powder or in the form of granules. They contain modified poly- 10 condensates of aspartic acid as nitrification-inhibiting additive. If the pyrazole compound is ionically bound to polyaspartic acid, it is preferable to start from mixtures which have been prepared beforehand. However, it is also possible to first coat a particulate mineral fertilizer with a pyrazole compound and then to apply polyaspartic acid or polyaspartimide.

It is also possible to first coat particulate mineral fertilizers with polyaspartic acid or polyaspartimide and then to apply at least one pyrazole compound. In this case, the pyrazo compounds are preferably bound ionically to polyaspartimide or polyaspartic acid. The polycondensates of aspartic acid modified with pyrazole compounds to be used according to the invention as nitrification inhibitors are used, for example, in amounts of 0.01 to 20, preferably 0.05 to 5% by weight, based on the fertilizer.

The use of polyaspartic acids for the treatment of mineral fertilizers which contain nitrification inhibitors leads to improved fixation of the nitrification inhibitors in the mineral fertilizer. The volatility of the nitrification inhibitor is greatly reduced, so that the storage stability of the mineral fertilizer treated increases. A loss of nitrification inhibitor during storage or when spreading to the floor is practically avoided.

In addition, the treatment according to the invention and the mineral fertilizers obtained in this way have the advantage of being environmentally safe. They do not contain any toxic substances such as zinc, copper or manganese, which in large quantities severely limit the environmental impact and can lead to soil contamination. Furthermore, the treatment according to the invention can be carried out inexpensively. Due to the greatly reduced volatility, the amount of nitrification inhibitors in the mineral fertilizer can be reduced by the treatment according to the invention, which leads to reduced costs and better environmental compatibility of the fertilizers according to the invention.

The percentages in the examples mean percent by weight. The K values of the condensates were determined according to H. Fikentscher, Cellulose-Chemie, Vol. 13, 58-64 and 71-74 (1932) in aqueous solution or in dimethylformamide at a concentration of the condensates of 1% by weight and a temperature determined from 25 ° C. 11

Manufacture of polyaspartic acid imide

50 kg of aspartic acid are introduced into a tumble dryer with a capacity of 200 l and polycondensed while passing through a stream of nitrogen 5 (500 l / h) within 6 hours at a temperature of the heat transfer oil of 220 ° C. until 95% of the theoretically possible amount of water have formed. The reactor is then cooled and the polycondensate is used for the hydrolysis without further purification, see Examples 5 to 8. The K value 0 is 17.0 (measured 1% in dimethylformamide).

example 1

In a 2 liter glass reactor equipped with a stirrer and distillation bridge, 266 g of L-aspartic acid (2 mol), 38.4 g of 3, 4-dimethylpyrazole (0.2 mol) and 300 g are stirred with vigorous stirring Mixed water and heated to a temperature of 160 ° C to distill off water. After removing the solution water, the condensation is carried out at normal pressure and a temperature of 20 250 ° C. After a reaction time of 10 h at 250 ° C, the polycondensation reaction is complete. After the reactor has cooled, the modified polyaspartimide is obtained as a beige powder, which is used without further purification. The K value of this modified polyaspartimide is 14.8 (measured 1% in dimethylformamide).

In order to produce an aqueous sodium salt solution from the modified polyaspartimide, 10 g of polyaspartimide are dispersed in 100 ml of water, the mixture is heated to 60 ° C. and a sufficient amount of 50% sodium hydroxide solution is added at this temperature until the pH in the range between 7 and 8 lies. The powder dispersed in water gradually dissolves to form a clear aqueous solution. The K value of this modified sodium polyaspartate is 20.0 (measured 1 ig in water).

35

Example 2

In a 2 liter glass reactor equipped with a stirrer and distillation bridge, 266 g

40 L aspartic acid (2 moles), 38.4 g 3,4-dimethylpyrazole (0.2 moles), 35.5 g 75% phosphoric acid and 300 g water mixed and heated to a temperature of 160 ° C to make water to distill off. After removing the solution water, the condensation is carried out at normal pressure and a temperature of 250 ° C. After a

45 reaction time of 10 h at 250 ° C, the polycondensation reaction is complete. After cooling the reactor, the modified polyaspartimide is obtained as a beige powder, which is without further 12

Cleaning is used. The K value of this modified polyaspartimide is 15.9 (measured 1% in dimethylformamide).

In order to produce an aqueous sodium salt solution from the modified polyaspartimide, 10 g of polyaspartimide are dispersed in

100 ml of water, the mixture is heated to 60 ° C. and, at this temperature, a sufficient amount of 50% sodium hydroxide solution is added until the pH is between 7 and 8. The powder dispersed in water gradually dissolves to form a clear aqueous solution. The K value of this modified sodium polyaspartate is 19.5 (measured 1% in water).

Example 3

In a 2 liter glass reactor equipped with a stirrer and distillation bridge, 266 g of L-aspartic acid (2 mol), 19.2 g of 3,4-dimethylpyrazole (0.2 mol) and 300 g of water are mixed with vigorous stirring and heated to a temperature of 160 ° C to distill off water. After removing the solution water, the condensation is carried out at a pressure of 50 mbar and a temperature of 250 ° C. After a reaction time of 10 h at 250 ° C, the polycondensation reaction is complete. After the reactor has cooled, the modified polyaspartimide is obtained as a beige powder, which is used without further purification. The K value of this modified polyasparimide is 14.7 (measured 1% in dimethylformamide).

In order to produce an aqueous sodium salt solution from the modified polyaspartimide, 10 g of polyaspartimide are dispersed in 100 ml of water, the mixture is heated to 60 ° C. and 50% sodium hydroxide solution is added at this temperature until the pH in the range between 7 and 8 lies. The powder dispersed in water gradually dissolves to form a clear aqueous solution. The K value of this modified sodium polyaspartate is 21.3 (measured 1% in water).

Example 4

In a 2 liter glass reactor equipped with a stirrer and distillation bridge, 266 g of L-aspartic acid (2 mol), 19.2 g of 3, 4-dimethylpyrazole (0.2 mol), 35.5 are added with vigorous stirring g 75% phosphoric acid and 300 g water mixed together and heated to a temperature of 160 ° C to distill off water. After removing the solution water, the condensation is carried out at a temperature of 250 ° C. The polycondensation reaction is complete after a reaction time of 6 h at 250 ° C. After cooling the reactor, the mode - 13 refined polyaspartimide as a beige powder, which is used without further purification. The K value of this modified polyaspartimide is 16.6 (measured 1% in dimethylformamide).

In order to produce an aqueous sodium salt solution from the modified polyaspartimide, 10 g of polyaspartimide are dispersed in 100 ml of water, the mixture is heated to 60 ° C. and 50% sodium hydroxide solution is added at this temperature until the pH in the range between 7 and 8 lies. The powder dispersed in water gradually dissolves to form a clear aqueous solution. The K value of this modified sodium polyaspartate is 23.0 (measured 1% in water).

Example 5

In a 500 ml Erlenmeyer flask equipped with a magnetic stirrer and reflux condenser, 97 g of the above-described polyaspartimide (1 mol) are dispersed in a solution of 48 g of 3,4-dimethylpyrazole (0.5 mol) in 200 ml of water. The reaction mixture is then heated under reflux with stirring for 10 hours, during which time the dispersed powder gradually dissolves into a clear aqueous solution, the pH of which is 4.4. The modified polyaspartate thus obtained has a K value of 8.7 (measured 1% in water).

Example 6

In a 500 ml Erlenmeyer flask equipped with a magnetic stirrer and a reflux condenser, 97 g of the polyaspartimide described above (1 mol) are dispersed in a solution of 96 g of 3, 4-dimethylpyrazole (1 mol) in 200 ml of water. The reaction mixture is then heated under reflux with stirring for 10 hours, during which time the dispersed powder gradually dissolves into a clear aqueous solution, the pH of which is 4.8. The modified polyaspartate thus obtained has a K value of 9.4 (measured 1% in water).

Example 7

In a 100 ml Erlenmeyer flask equipped with a magnetic stirrer and reflux condenser, 9.7 g of the above-described polyaspartimide (0.1 mol), 1.2 g of 3, 4-dimethylpyrazole (0.0125 mol) and 20 ml of dimethylformamide mixed. The reaction mixture is slowly heated to 100 ° C. until all the insoluble parts go into solution. The reaction mixture is then heated under reflux for 20 hours with stirring. After removing the solvent in vacuo, a brownish powder is obtained. The The 14 K value of this modified polyimide is 9.8 (measured 1% in dimethylformamide).

In order to produce an aqueous sodium salt solution from the modified polyaspartimide, 1 g of the polyaspartimide is dispersed in 10 ml of water, the mixture is heated to 60 ° C. and a sufficient amount of 50% sodium hydroxide solution is added at this temperature to bring the pH in the range is between 7 and 8. Here, the powder dispersed in water gradually dissolves to form a clear aqueous solution. The K value of this modified sodium polyaspartate is 11.2 (measured 1% in water).

Example 8

In a 100 ml Erlenmeyer flask equipped with a magnetic stirrer and a reflux condenser, 9.7 g of the above-described polyaspartimide (0.1 mol), 2.5 g of 3, 4-dimethyIpyrazoI (0.025 mol) and 20 ml of dimethylformamide mixed. The reaction mixture is slowly heated to 100 ° C. until all the insoluble parts go into solution. The reaction mixture is then heated under reflux for 20 hours with stirring. After removing the solvent under vacuum, a brownish powder is obtained. The K value of this modified polyaspartimide is 9.8 (measured 1% in dimethylformamide).

In order to produce an aqueous sodium salt solution from the modified polyaspartimide, 1 g of this polyaspartimide is dispersed in 10 ml of water, the mixture is heated to 60 ° C. and at this temperature so much 50% sodium hydroxide solution is added that the pH in the range from 7 and 8 lies. This resolves itself in

Water gradually dispersed powder to form a clear aqueous solution. The K value of this modified sodium polyaspartate is 11.2 (measured 1% in water).

Example 9

2.77 g (0.029 mol) of 3,4-dimethylpyrazole were added to 100 ml of a 6.5% strength aqueous solution of unneutralized polyaspartic acid (0.056 mol, molecular weight M _w = 30,000, K value ( determined 1% in water) of 9). A clear aqueous solution was obtained which had a pH of 4. It can be used directly as a nitrification inhibitor for fertilizers. 15

Example 10

Example 9 was repeated with the exception that 4.88 g (0.051 mol) of 3, -dimethylpyrazole was used. The clear aqueous solution formed was evaporated to dryness in a rotary evaporator under reduced pressure. The remaining solid was isolated and ground to an average particle size of 50 microns. The powdery mixture, which contains 3, -dimethylpyrazole ionically bound to polyaspartic acid, is used as a nitrification inhibitor for fertilizers.

Synergies between nitrification inhibitors and polyaspartate applications in agriculture and horticulture

The invention relates to the combined use of nitrification inhibitors (NI) and polyaspartate, the sodium salt of polyaspartic acid (PAA), molecular weight 6000, in formulated fertilizers or as an application of the individual components to the soil, to culture substrates or in nutrient solution systems and in fertilization systems such as Fertigation.

NI _4- containing or NH ₄ -releasing fertilizers are added to delay the oxidation of NH ₄ to N0 ₃ . In contrast to N0 _3, NH ₄ is bound to the negative soil colloids and is therefore subject to practically no washout in soil layers below the root area. Since NI delays the NH ₄ conversion into N0 ₃ , gaseous N losses due to denitrification from N0 to N ₂ 0 are also reduced. The use of PAA in agriculture and horticulture is patented as a promoter of nutrient uptake and plant growth (US-A-5, 350, 735).

The following describes that the combined use of NI and PAA together with fertilizers.

a) synergistically promotes the growth of plants (Tables A and C),

b) the N uptake of plants is promoted synergistically (Table C),

c) the chlorophyll content of the leaves is synergistically highest (Tables A and B), and

d) the N0 ₃ levels in plants are lowest (Table D).

Trials and methods 16

The chlorophyll content of cotyledons was determined using a SPAD meter (from Minolta). The SPAD values determined are directly proportional to the chlorophyll content of the leaves examined (Marquard and Tipton (1987) HortScience 22, 1327). Synergy effects were determined using the method of Colby (1967) (Weeds 15, 20-22). Here, an expected value is calculated from the effect of the individual components and compared with the relative value of the combination effect. If the expected value is below the relative value of the combination effect, a synergistic effect can be assumed.

Example A

Try mustard as a test plant

Pots with 660 g soil were applied with the fertilizer varieties. Then 20 mustard seeds ("Maxi" variety) were laid out per pot. The culture of the plants took place up to 50 days after sowing with optimal water supply by watering daily at 60% of the maximum water capacity of the soil. ASA was fertilized with 100 mg N / pot. The tests were divided into tests (i) with fully formulated fertilizers and (ii) in tests with individual addition of the components ASS, NI (DMPP) and PAA to the soil.

(i) The formulated fertilizers were ASS, ASS plus 0.3% DMPP based on weight ASS and ASS plus 0.3% DMPP based on goods plus 0.25% PAA based on weight ASS and 1% PAA based on weight ASS .

(ii) When (ii) adding the components individually to the soil, the NI was used alone in accordance with the application rate in the formulated fertilizer and PAA was applied in the application amounts of 10, 100 and 1000 mg / kg of soil.

The results are shown in Table A for fully formulated fertilizers and in Table B for the fertilization of the individual components.

Example B

Trial with citrus fertigation

Citrus was cultivated with one plant per pot in 20 liters of soil. Fertigation was carried out every 14 days with ammonium sulfate, ammonium sulfate + NI (DMPP) and ammonium sulfate + NI + PAA in an application rate corresponding to 4 l (40% PAA solution) / ha. 17

The results are shown in Table C.

Example C

Field trials on rapeseed

In 5 field trials (randomized blocks with four repetitions) with winter rape, ASS, ASS + 0.3% DMPP (based on weight) ASS + 0.3% DMPP (based on weight ASS) + 4 L PAA (40% solution) / ha each fertilized with one application. The N application rate was 100 kg / ha N.

The N0 ₃ content of the stems (stem base of the main shoot) was determined after 2, 4, 6 and 8 weeks after fertilizer application using the Nitacheck method.

The results are shown in Table D.

Example D

Field trials on wheat

In field trials (randomized blocks with four repetitions) with winter wheat, ASS, ASS + x L PAA (40% solution) / ha, ASS + 0.3% DMPP (based on weight ASS) and ASS + 0.3% DMPP (related on weight ASS) + x L PAA (40% solution) / ha fertilized. The N application rate was 180 kg / ha N. ASS and ASS - PAA was applied in 3 doses (80 kg / ha N at the start of vegetation, 40 kg / ha N at EC30 / 32, 60 kg / ha N at EC 49/51 ). ASS + DMPP and ASS + DMPP + PAA were applied in two doses (100 kg / ha N at the start of vegetation, 80 kg / ha N at EC 32/37). was harvested

Grain yield (86% DM), the N content in the grain (using the Dumas method) and the N withdrawal were determined. The income components were also recorded.

The results are shown in Table E.

Used abbreviations:

DMPP = 3, 4 -dimethylpyrazole -phosphate ASS = ammonium sulfate nitrate

AS = ammonium sulfate

NI = nitrification inhibitor (DMPP)

PAA = polyaspartate

FS = fresh matter mass of the shoot TS = dry matter mass of the plant

SPAD value = chlorophyll index of the SPAD meter

Where = week 18th

N = nitrogen

L = liter

Ha = hectare kg = kilogram rel. = relative ppm = parts per million [e.g. Mg / kg) g = grams

Try Mustard

Table A

Influence of ASS, ASS + NI and ASS + NI + PAA as a formulated fertilizer added to the soil on the shoot growth and the chlorophyll content of the leaves.

Growth chlorophyll

[g FS / rel. Expected (SPAD rel. .Rwar- pot] (%) value) (%) value

ASS (control) 19.4 100 35.0 100

ASS + NI 16.0 82 35.2 101

ASS + PAA (0.25%) 21.7 112 28.3 81

ASS + PAA (1.0%) 18.5 95 30.8 88

ASS + NI + PAA 19.0 98 92 31.1 89 82 (0.25%)

ASS + NI + PAA 19.1 98 78 35.3 101 89 (1.0%)

Table B

Influence of ASA, NI and PAA as individual components added to the soil on the chlorophyil content of the 31 leaves

Chlorophyll content

(SPAD rel. Expected value) (%) valuation value

ASS (control) 35.0 100

ASS + NI 35.2 101

ASS + PAA (10 mg / kg) 33.4 95

ASS + PAA (100 mg / kg) 35.3 101

ASS + PAA (1000 mg / kg) 35.2 101

ASS + NI + PAA (10 mg / kg) 37.8 108 96

ASS + NI + PAA (100 mg / kg) 35.9 103 102

ASS + NI + PAA (1000 36.7 105 102 mg / kg) 19

Citrus trial

Table C.

Influence of AS, AS + NI and AS + NI + PAA as fertigation on the N uptake of the plant and the growth

N admission growth

[g / rel. Expected [g S / rel. Erwar¬

Pot] (%) pot - worth]

AS (control) 3.31 100 206.0 100

AS + NI 3.06 92 208.9 101

AS + PAA (4L / ha) 4.04 122 222.1 108

AS + NI + PAA 4.38 132 112 257.5 125 109 (4L / ha)

Rape experiments

Table D

Influence of ASS, ASS + NI and AΞS + NI + PAA on the N03 levels in the stem in the field test.

N03 content of the stem [ppm]

2 weeks 4 weeks 6 weeks 8 weeks

ASS 2348 2476 2387 1771

ASS + NI 2323 1748 1658 1319

ASS + NI + PAA 2093 1691 1551 1238 (4L / ha)

Field trial on wheat

Table E

Claims

20 patent claims

1. Modified polycondensates of aspartic acid, characterized in that they contain 0.1 to 50 mol% of at least one nitrification inhibitor, preferably a pyrazole compound covalently or ionically bound, or mixtures of nitrification inhibitor (s) to the polycondensate of aspartic acid in a weight ratio of 0. 01: 1 to 10: 1.

2. Fertilizers containing modified polycondensates of aspartic acid, characterized in that they contain 0.1 to 50 mol% of at least one nitrification inhibitor, preferably a pyrazole compound bound covalently or ionically, or mixtures of nitrification inhibitor (s) to the polycondensate of aspartic acid in a weight ratio of 0 , 01: 1 to 10: 1.

3. Modified polycondensates of aspartic acid according to claim 1 or 2, characterized in that they are obtainable by polycondensation of

(a) Aspartic acid, mixtures of aspartic acid and thus co-condensable compounds as well as the alkali metal or ammonium salts of aspartic acid

(b) at least one nitrification inhibitor, preferably a pyrazole compound and

optionally subsequent hydrolysis of the aspartimide units formed during the condensation to form aspartic acid units or their salts with alkali metal, alkaline earth metal or ammonium bases.

4. Modified polycondensates of aspartic acid according to claim 1 or 2, characterized in that they are obtainable by polymer-analogous reaction of

(a) With aspartimide units containing polycondensates

(b) at least one nitrification inhibitor, preferably a pyrazole compound and 21 optionally at least partial hydrolysis of the unreacted aspartimide units to aspartic acid units or their salts with alkali metal, alkaline earth metal or ammonium bases.

5. Modified polycondensates of aspartic acid according to claim 1 or 2, characterized in that they are obtainable by mixing

(a) Polycondensates containing aspartic acid units or their alkali metal or ammonium salts

(b) at least one nitrification inhibitor, preferably a pyrazole compound.

6. Modified polycondensates of aspartic acid according to one of claims 1 to 5, characterized in that the pyrazole compound (b) is 3, 4-dimethylpyrazole, 3-methylpyrazole, 4-chloro-3-methylpyrazole, the phosphoric acid addition salts of the compounds mentioned, N- Hydroxymethyl-3, 4-dimethylpyrazole or N-hydroxymethyl-4-chloro-3-methylpyrazole.

7. Modified polycondensates according to one of claims 1 to 4, characterized in that they are obtainable by condensing

(a) aspartic acid and

(b) at least one compound from the group 3-methyl-pyrazole, 3, -dimethylpyrazole, 4-chloro-3-methylpyrazoi and the phosphoric acid addition salts of these compounds and optionally subsequent hydrolysis of the aspartimide units of the condensates to aspartic acid units or their salts with alkali metal, alkaline earth metal - or ammonium bases.

8. A process for the preparation of modified polycondensates of aspartic acid according to one of claims 1 to 7, characterized in that

(b) at least one nitrification inhibitor, preferably a pyrazole compound 22 condensed at temperatures from 120 to 270 ° C or

at least one pyrazole compound is added to polycondensates containing aspartimide units and, if appropriate, the 5 aspartimide units of the condensates are hydrolyzed to aspartic acid units and optionally neutralized with alkali metal, alkaline earth metal or ammonium bases or polycondensates containing aspartic acid units or their alkali metal or ammonium salts, preferably with at least one nitrate compound, with at least one nitrite compound mixes.

9. The method according to claim 8, characterized in that as pyrazole compound (b) 3, 4-dimethylpyrazole, 3-methylpyrazole, 4-chloro-3-methyipyrazole, the phosphoric acid addition salts 5 of the compounds mentioned, N-hydroxymethyl-3, 4-dimethylpyrazole or N-hydroxymethyl-4-chloro-3-methylpyrazole.

10. Use of the modified polycondensates of aspartic acid according to one of claims 1 to 7 as nitrification inhibitor.

11. Mineral fertilizer, characterized in that they contain modified polycondensates of aspartic acid according to one of claims 1 to 7 as a nitrification-inhibiting additive.

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12. Mineral fertilizer, characterized in that they contain polycondensates of aspartic acid and nitrification-inhibiting additives as finished formulations.

30 13. Use of one or more mineral fertilizers, one or more polycondensates of aspartic acid and one or more nitrification inhibitors as individual components for fertilization at a fertilization appointment.

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