DE102013008687A1 - Production of aqueous reaction solutions based on vegetable hydroxycinnamic acids (phenolic acids / phenylpropanoids / phenylpropenes) and lignin for the coating of fertilizer granules. In particular: preparation of appropriate reaction solutions - Google Patents

Abstract

So far, water-based liquids for coating fertilizer granules have not been produced on the basis of plant hydroxycinnamic acids, which are obtained as residues in the extraction of plant biomass. The coating obtained must be water-insoluble and become microporous in order to achieve a controlled release of the nutrients from the granulate. During the production of the coating, the polymer must be cured on the surface of the granulate so quickly that the disintegration of the water-soluble granulate is prevented. This is made possible by a two-stage polymerization process. In the first stage, the monomeric hydroxycinnamic acids are prepolymerized in a highly concentrated, dissolved form with an inorganic peroxide. Surprisingly, the reaction products remain very soluble in water. After the solution with reaction products (reaction solution) has been applied to the granules, the second stage of the polymerization takes place. This is achieved by the high concentration of the polymer precursors in the aqueous phase and rapid heating of the granulate. The two-stage process can also be carried out after partial substitution of the hydroxycinnamic acids with very good lignin sulfonate. The coating of the granules based on vegetable hydroxycinnamic acids is completely bio-based and biodegradable. In combination with the under-foot fertilization, the coated granules serve a sustainable agricultural practice in which nutrient losses are reduced by adsorption on clay minerals and nutrient discharge from agro-ecosystems.

Description

Technical status

There has been a steadily increasing number of controlled-release fertilizers for about 20 years, all of which aim to control or delay the delivery of nutrients to counteract leaching into ground and surface waters and gaseous emissions ( 1-3). Commercially prepared coatings are based on sulfur compounds, water-insoluble paraffin waxes or are polymeric in nature. In the polymers, various plastics are used: on the one hand thermoplastic petrochemical plastics z. In Nutricote (Chisso-Asahi Fertilizer Company Ltd., Tokyo, Japan; JP200239090 on the other hand thermoset bio-based polymers in Osmocote (Grace Sierra Horticultural Products Co, Marysville, Ohio, USA). Osmocote coatings consist of resinified vegetable oils. Reaction resins based on linseed oil or soybean oil are commercially available for coating various surfaces under the trade name Tribest from Cognis Germany and Mercryl from Hobum Oleochemicals GmbH. In Mercryl products, the fatty acids contained in the vegetable oil have been functionalized with acrylate groups after epoxidation. The crosslinking of the acrylate groups takes place by means of radical polymerization, for which purpose a peroxide initiator is used (for example EP 1894949 (B1) ). For the thermoplastic fertilizer coatings, methods have been published in which a biodegradable polymer is mixed with the petrochemical polyolefin ( JP2002145691 ). Also belonging to the thermoplastics coatings that are based exclusively on renewable resources, eg. As polymerized lactic acid based are available (EG2007NA01371).

While lactic acid must be produced by fermentation from sugars, lignin accumulates worldwide as a residue of paper and pulp production in an amount of 70 million tons, of which only a maximum of 2% is recycled. Therefore, there is great interest in industrial processes in which lignin replaces more expensive raw materials of the chemical industry. Coatings of fertilizer granules based on lignins are known in the art (4, 5). Resins dissolved in alcohol serve to attach the lignin powder. It is known that lignin powder can also be bound to urea granules with 0.05-0.2% by weight polyacrylamide solution, with the additional use of a vegetable oil for sealing the surface ( CN101062878 ). The mixture of hydrophilic components, including lignin, with hydrophobic bio-based polymers is described for pesticides as a carrier material which adheres to vegetable surfaces and releases the active ingredient in a controlled manner ( WO2010039865 ). Another vegetable waste from the aromatics group is ferulic acid, a by-product of the extraction of olive oil and rice oil, which is present in high concentrations in waste water from the corresponding extraction plants and pollutes the natural waters. Ferulic acid belongs to the hydroxycinnamic acids which have an acrylic acid residue in addition to a phenolic hydroxyl group. Unlike lignin, ferulic acid is currently only partially absorbed as process waste. Ferulic acid is in demand on the world market as a raw material for vanillin production, plays a role in sunscreens as a UV absorber and is particularly appreciated in China in pharmaceutical preparations due to its antioxidant and anti-inflammatory properties. A Chinese patent describes a process for the extraction of ferulic acid ( CN101811958 ), which underlines the industrial demand for this substance. Ferulic acid can be chemically polymerized (6), is known as crosslinker in plant cell walls (7) and due to the reactive groups as a bio-based binder / crosslinker in lignin-containing coating solutions into consideration to accomplish the attachment of the lignin granules.

The covalent crosslinking of lignin with other substances in plastics is state of the art: (1) Duroplastic (curable) polycondensates of lignin and substances with amino groups have long been described (8). Urea fertilizers in which the urea is covalently crosslinked with lignin for the purpose of sustained release are known ( WO20050007700 ; WO2011005175 ). Another type of domplastic lignin-containing polycondensates is prepared by reaction with aldehydes, especially formaldehyde ( RU2009129419 ; CN102174159 ; CN101092472 ; JP2007169491 ; US2003045665 ; HU194920 ; GB1601751 ; TW201207036 ). (2) The formation of thermoset polyadducts from lignin, epoxies and a vegetable polyphenol co-crosslinker was presented at this year's DECHEMA colloquium "Lignin as a natural resource for the chemical industry".

The radical polymerization of petrochemical acrylic compounds (acrylic acid and acrylamide) after dripping onto fertilizer granules corresponds to the prior art (9).

Such fertilizer coatings can store a great deal of water and at the same time delay the nutrient delivery, so that they are particularly suitable for fertilization in arid areas. It is It is known that the acrylic monomers also polymerize in the presence of organically modified clay minerals and powdered wheat straw. These functional fillers reduce the need for expensive petrochemical monomers and increase biodegradability. Mingzhu Liu's group at State Key Laboatory of Lanzhou University (China) produced laminates for urea and phosphate fertilizers (10, 11). The group of Aiqin Wang at the Center of Ecological and Green Chemistry in Lanzhou carried out the polymerization of acrylic monomers in the presence of humic acids (12). Humic acids resulting from the degradation of plant material in the soil, in addition to aliphatic components and aromatic degradation products of lignin and unsaturated vegetable polyester (suberin) and have a variety of carboxyl and phenolic hydroxyl groups. The polymerization of this composite material was carried out in aqueous solution with the exclusion of oxygen. As the initiator of the polymerization, ammonium persulfate was used in a concentration of 0.1% (w / v). The total concentration of acrylic monomers in the starting solution was 20% (w / v), of which 0.1% (w / w) accounted for methylenebisacrylamide as a bifunctional crosslinker (12). The proportion by weight of humic acids in the composite materials was between 5 and 40% (w / w). The reaction product was a water-insoluble polymer from which humic acids were released for up to 40 days when placed in distilled water.

However, none of the processes described permits a purely water-based coating process for fertilizer granules without the use of petrochemical products, amino compounds, aldehydes, toxic acrylic compounds or plant-based precursors, for which there is a strong competition for use, in particular with food production. Resins for attaching lignin powder to fertilizer granules must be dissolved in organic solvents. Polyacrylamide as an alternative binder and the acrylic monomers used for the embedding of humic acids are petrochemical products. The vegetable oils are nutritionally relevant and are used for the production of detergents as well as energetically. The current production of polylactic acid from corn starch is in direct competition with food production.

The invention mentioned in claim 1 is based on the problem of replacing petrochemical acrylic compounds in fertilizer coatings for delayed release of nutrients by bio-based acrylic compounds.

The problem is solved by the listed in claim 1 oxidative conversion of plant hydroxycinnamic acids in highly concentrated solution to an aqueous reaction solution, the wetting of the fertilizer granules with the reaction solution and the curing of the solution on the granules.

The invention mentioned in claim 6 (independent claim) is based on the problem of simplifying the use of aqueous lignin solutions or lignin suspensions for coating fertilizer granules so that neither solvent, nor oleochemical, petrochemical or toxic binder / crosslinker / reactants are required.

This problem is solved by the addition of lignin described in claim 6 to the reaction solutions prepared according to claim 1.

Advantages of the invention: The present invention describes a method by which an aqueous coating solution for fertilizer granules is produced, wherein apart from ammonium persulfate (APS) as a possible polymerization initiator exclusively bio-based components are used which are obtained as residues in industrial processes. Surprisingly, these components can be treated in concentrated solution with APS so that a very readily water-soluble prepolymer is formed, which can then be transferred after application to the fertilizer granules in a water-resistant coating.

Advantageous embodiments of the invention without the addition of lignin are shown in claims 2 to 5. Claims 2 to 4 describe the preparation and composition of reaction solutions. Thereafter, reaction solutions for coating fertilizer granules can be prepared from ferulic acid using ammonium persulfate. For curing the water-soluble coating, claim 5 calls a thermal process.

Advantageous embodiments of the invention with the addition of lignin are mentioned in claims 6 to 8. Claim 9 is the use of the invention for the coating of fertilizer granules, while claim 10 shows that dried reaction solutions according to claims (2) and (7) can also be processed into a plastic granules.

embodiments

shows the delayed release of phosphate from triple superphosphate granules, which was provided with three different coatings based on ferulic acid (b2, c1, c2). K represents uncoated granule control. Batch 2 differs from batches c1 and c2 by a lower concentration of ammonium persulfate in the prepolymerization (Table 1). The attached number indicates the number of coating operations with the respective reaction solution. To measure the release by distilled water, the granules were placed on a paper filter which was in a funnel. Per extraction, 10 mL of water was added and the filtrate collected for P concentration determination. The extraction was repeated ten times. The values shown are mean values from two filter approaches. Table 1 component embodiments b2 c1 / c2 c1 Ferulic acid (g) 2.4 → 0.03 Acetone (mL) 8th → 0 NaOH 0.5 M (mL) 2 → 0.6 NaOH 6M (mL) 1.83 → 0 Lignosulfonate (g) 0 0 0.12 APS, 100 mg / mL (μL) 80 800 39

Out It can be seen how much phosphorus had sprouts after cultivation on a soil substrate, which had been fertilized with uncoated or coated granules. The fertilization experiment in the climate chamber was carried out according to the following methodology: four corn caryopses of the AMADEO variety (KWS, Kleinwanzleben, Germany) were sown in a vessel with 1 kg of soil (soil type Ferralsol). After two weeks, the number of plants was reduced to two. The experiment included five variants according to Table 2 with four vessels each. TSP means triple superphosphate. In the variants with TSP, 0.51 g granules were applied per vessel about 1 cm below the corn kernels (under-foot fertilization). Except for P, all vessels were supplied with the same amount of N, K, Mg, S, Cl, Mn, Zn, Cu, Mo, and B by addition in dissolved form. The harvest took place 31 days after sowing. Table 2 variant description N Control, no P fertilization K TSP, granulated, no coating c1 TSP with a simple coating of type c c2 TSP with double coating of type c b2 TSP with double coating type b

Table 1 also illustrates the composition for one embodiment of the highly water-soluble lignin sulfonate (Lc1). The water resistance of the coating prepared with the described reaction solution was detected by placing in distilled water for one day. The pH of all reaction solutions is between 9 and 10, d. H. in the buffer region of the phenolic hydroxyl group of ferulic acid. Such a slightly alkaline pH of the reaction and thus the coating solution is important for the coating success. At lower pH values, the wettability of the triple superphosphate granules is low and at a pH above 11, these granules partially dissolve.

• (1) Zur Herstellung der Reaktionslösungen wird undissoziierte Ferulasäure verwendet. Bei Verwendung von Ferulat muss die in Tabelle 1 angegebene NaOH-Konzentration erniedrigt werden.
• (2) Das Herstellen der hochkonzentrierten Lösung von Ferulasäure in verdünntem Aceton gelingt nur dann ohne Ferulatausfällung, wenn die konzentrierte NaOH vorsichtig unter die wässrige Acetonphase, welche die vollständig gelöste Ferulasäure enthält, unterschichtet wird. Dadurch entsteht ein durchscheinender gelber Bodensatz, der auf die Mitnahme von Ferulasäure und dessen vollständige Dissoziation (inkl. phenolische Hydroxylgruppe) zurückgeht. Die Lösung muss dann sofort gemischt, anschliessend auf 60°C erwärmt und so lange wiederholt gemischt werden, bis eine klare Lösung erhalten wird. Im Detail ist die Vorgehensweise folgendermaßen: Das Reaktionsgefäß wird aus dem Wasserbad (60°C) genommen und nach nur leichtem Abkühlen auf ca. 45°C geöffnet. Die darin enthaltene Lösung wird vom Rand her langsam mit 6 M NaOH unterschichtet. Dann wird das Gefäß sofort verschlossen und der Inhalt auf dem Whirlmix (Vortex) behutsam vermischt, bis der Bodensatz sich weitgehend gelöst hat. Die Drehzahl des Whirlmix ist so einzustellen, dass die Lösung nicht bis an den Deckel des Gefäßes gelangt. Dadurch wird der Sauerstoff-Kontakt mit der Lösung begrenzt. Das Gefäß wird wieder für 5 min ins Wasserbad gestellt und danach der Inhalt erneut behutsam gemischt, bis sich der restliche gelbe Bodensatz vollständig aufgelöst hat. Beim Mischen ist eine Abkühlung unter 40°C zu vermeiden und das Gefäß bei Bedarf erneut ins Wasserbad zu stellen, soweit noch keine klare Lösung vorliegt.
• (3) Die saure Wirkung von Ligninsulfonat kann je nach Quelle der Substanz unterschiedlich stark ausfallen. Das Ausführungsbeispiel in Tabelle 1 bezieht sich auf Ca-Ligninsulfonat der Carl Roth GmbH (Produkt-Nr. 8208.1). Für andere Ligninsulfonate muss die NaOH-Konzentration überprüpft werden.
• (4) Die Zugabe von APS erfolgt vor Erwärmen der Reaktionsmischung in der folgenden Weise: (a) Ammoniumpersulfat (APS) wird als Lösung in hochreinem Wasser (MilliQ-Anlage; Merck-Millipore) zugesetzt. (b) Die hochkonzentrierte Ferulatlösung bzw. die Ligninsulfonat-Ferulat-Lösung wird auf Raumtemperatur abgekühlt. Die APS-Lösung wird tropfenweise über den Rand in das Gefäß eingeleitet, das Gefäß verschlossen und sofort behutsam vermischt. Diese Mischung ist bei Raumtemperatur gegenüber Ausfällungen mindestens 10 min stabil.
• (5) Die Reaktionsmischung wird nach APS-Zugabe und vor Erwärmen mit Argon überschichtet. Andere inerte Gase können verwendet werden, solange gewährleistet ist, dass kein Sauerstoff in die Reaktionsmischung eingetragen wird.
• (6) Die Reaktionsmischung wird 3 h bei 60°C inkubiert.
• (7) Die Ansätze ohne Ligninsulfonsäure (b und c) können statt in 80%igem Aceton auch in 12 mL einer 1,6 M NaOH-Lösung durchgeführt werden.
• (8) Bei einem Ansatz mit Aceton kann der Acetonanteil nach der Inkubation verdampft werden und das zurückbleibende Gel mit einem dem Aceton äquivalenten Volumen an Wasser wieder gelöst werden.
• (9) Das Gel kann auch mit im Überschuss vorhandenem Polymerisationsinitiator bei erhöhter Temperatur weiter umgesetzt werden.
• (10) Weiterhin kann das Gel getrocknet werden und als Reaktionsharz thermisch in einen duroplastischen Kunststoff umgewandelt werden.
• (11) Für die Ausführungsbeispiele wurde Tripelsuperphosphat der Firma Triferto (Doetinchem, NL) verwendet. Das wasserlösliche Produkt enthält 45% Phosphorsäureanhydrid.
• (12) Zur Herstellung einer Düngerbeschichtung wird das Düngergranulat mit der Reaktionslösung benetzt und 10 min bei 80°C getrocknet. Soweit noch Aceton in der Reaktionslösung enthalten ist, wird es vorher abgedampft.
• (13) Das Aushärten des Oberflächenrückstands wird durch 10-minütiges Erhitzen bei 160°C erzielt. Bei Auftragung von zwei Schichten (siehe Ausführungsbeispiele) beträgt die Erhitzungszeit jeweils 5 min.

The following information will provide those skilled in the art with the information needed to prepare the reaction solutions and coatings described in the embodiments.

• (1) Undissociated ferulic acid is used to prepare the reaction solutions. When using ferulate, the NaOH concentration indicated in Table 1 must be lowered.
• (2) The preparation of the highly concentrated solution of ferulic acid in dilute acetone succeeds only without ferulat precipitation, when the concentrated NaOH is carefully submerged under the aqueous acetone phase containing the completely dissolved ferulic acid. This results in a translucent yellow sediment, which is due to the entrainment of ferulic acid and its complete dissociation (including phenolic hydroxyl group). The solution must then be mixed immediately, then heated to 60 ° C and mixed repeatedly until a clear solution is obtained. In detail, the procedure is as follows: The reaction vessel is taken from the water bath (60 ° C) and opened after only a slight cooling to about 45 ° C. The solution contained therein is slowly underlaid from the edge with 6 M NaOH. Then the vessel is closed immediately and the contents are mixed gently on the Whirlmix (Vortex) until the sediment has largely dissolved. The speed of the Whirlmix should be adjusted so that the solution does not reach the lid of the vessel. This limits the oxygen contact with the solution. The vessel is again placed in the water bath for 5 minutes and then the contents are gently mixed again until the remaining yellow sediment has completely dissolved. When mixing, avoid cooling below 40 ° C and, if necessary, place the vessel in the water bath again, if no clear solution is present.
• (3) The acidic effect of lignosulfonate may vary depending on the source of the substance. The exemplary embodiment in Table 1 relates to Ca lignosulfonate from Carl Roth GmbH (product No. 8208.1). For other lignosulfonates, the NaOH concentration must be checked.
• (4) APS is added prior to heating the reaction mixture in the following manner: (a) Ammonium persulfate (APS) is added as a solution in ultrapure water (MilliQ system; Merck-Millipore). (b) The high-concentration ferulate solution or the lignosulfonate-ferulate solution is cooled to room temperature. The APS solution is introduced dropwise over the edge into the vessel, the vessel is closed and immediately mixed gently. This mixture is stable at room temperature to precipitations for at least 10 minutes.
• (5) The reaction mixture is overcoated after addition of APS and before heating with argon. Other inert gases may be used as long as it is ensured that no oxygen is introduced into the reaction mixture.
• (6) The reaction mixture is incubated at 60 ° C for 3 hours.
• (7) The lignosulfonic acid (b and c) mixtures can also be carried out in 12 ml of a 1.6 M NaOH solution instead of 80% acetone.
• (8) In a acetone batch, the acetone portion can be evaporated after incubation and the residual gel redissolved with an acetone equivalent volume of water.
• (9) The gel can be further reacted with excess polymerization initiator at elevated temperature.
• (10) Further, the gel may be dried and thermally converted into a thermosetting resin as a reaction resin.
• (11) Tripel superphosphate from Triferto (Doetinchem, NL) was used for the exemplary embodiments. The water-soluble product contains 45% phosphoric anhydride.
• (12) To prepare a fertilizer coating, the fertilizer granules are wetted with the reaction solution and dried at 80 ° C for 10 minutes. As far as acetone is still contained in the reaction solution, it is previously evaporated.
• (13) The surface residue is cured by heating at 160 ° C for 10 minutes. When applying two layers (see embodiments), the heating time is 5 min.

literature

• 1. Davidson, D .; Gu, FX, Materials for sustained and controlled release of nutrients and molecules to support plant growth. J. Agric. Food. Chem. 2011, 60, (4), 870-876 ,
• Second Adams, C .; Frantz, J .; Bugbee, B., Macro- and micronutrient-release characteristics of three polymer-coated fertilizers: Theory and measurements. J. Plant Nutr. Soil Sci. 2013, 176, (1), 76-88 ,
• Third Tomaszewska, M .; Jarosiewicz, A., Use of polysulfone in controlled-release NPK fertilizer formulations. J. Agric. Food. Chem. 2002, 50, (16), 4634-4639 ,
• 4th Garcia, MC; Díez, YES; Vallejo, A .; Garcia, L .; Cartagena, MC, Use of Kraft pine lignin in controlled-release fertilizer formulations. Ind. Eng. Chem. Res. 1996, 35, (1), 245-249 ,
• 5th Garcia, MC; Vallejo, A .; Garcia, L .; Cartagena, MC, Manufacture and evaluation of coated triple superphosphate fertilizers. Ind. Eng. Chem. Res. 1997, 36, (3), 869-873 ,
• 6th Puoci, F .; Cirillo, G .; Settino, R .; Curcio, M .; Parisi, OI; Iemma, F .; Spizzirri, UG; Picci, N., UV protecting activity of ferulic acid polymeric derivative. Chimica Oggi-Chemistry Today 2010, 28, (2), 8-10 ,
• 7th Bunzel, M., Chemistry and occurrence of hydroxycinnamate oligomers. Phytochem. Rev. 2009, 9, (1), 47-64 ,
• 8th. Hänninen, T .; Hughes, M .; Baur, E .; Otremba, F .; Huber, T .; Graupner, N .; Muessig, J .; Premper, E .; van den Oever, M .; Bos, H .; Bandyopadhyay-Ghosh, S .; Bandhu Ghosh, S .; Sain, M., Composites. In Industrial Applications of Natural Fibers, John Wiley & Sons, Ltd: 2010; pp 381-480 ,
• 9th Guo, M .; Liu, M .; Zhan, F .; Wu, L., Preparation and properties of a slow-release membrane-encapsulated urea fertilizer with superabsorbent and moisture preservation. Ind. Eng. Chem. Res. 2005, 44, (12), 4206-4211 ,
• 10th Lang, R .; Liu, M., Preparation and properties of coated nitrogen fertilizer with slow release and water retention. Ind. Eng. Chem. Res. 2006, 45, (25), 8610-8616 ,
• 11th Xie, L .; Liu, M .; Ni, B .; Wang, Y., Utilization of wheat straw for the preparation of controlled-release fertilizer with the function of water retention. J. Agric. Food. Chem. 2012, 60, (28), 6921-6928 ,
• 12th Zhang, J .; Liu, R .; Li, A .; Wang, A., Preparation, swelling behaviors, and slow-release properties of a poly (acrylic acid-co-acrylamide) / sodium humate superabsorbent composite. Ind. Eng. Chem. Res. 2005, 45, (1), 48-53 ,

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• JP 200239090 [0001]
• EP 1894949 (B1) [0001]
• JP 2002145691 [0001]
• CN 101062878 [0002]
• WO 2010039865 [0002]
• CN 101811958 [0002]
• WO 20050007700 [0003]
• WO 2011005175 [0003]
• RU 2009129419 [0003]
• CN 102174159 [0003]
• CN 101092472 [0003]
• JP 2007169491 [0003]
• US 2003045665 [0003]
• HU 194920 [0003]
• GB 1601751 [0003]
• TW 201207036 [0003]

Claims (1)

(1) Oxidative conversion of plant Hydroxyzimtsäuren in highly concentrated solution to an aqueous reaction solution, which is applied to fertilizer granules and allowed to cure (2) Highly concentrated weakly acidic to slightly alkaline reaction solutions prepared from ferulic acid containing their oxidation and polymerization products (3) Reaction of hydroxycinnamic acids to produce the reaction solutions using chemical or biochemical initiators of radical polymerization reactions (4) Reaction method of (2) and (3) using ammonium persulfate (5) curing the reaction solution on the fertilizer granules by heating (6) Secondary claim: Oxidative conversion of hydroxycinnamic acids in the presence of lignin according to (2) to (4) to a reaction solution which is allowed to harden on fertilizer granules (7) Highly concentrated weakly acidic to slightly alkaline reaction solutions prepared from ferulic acid and lignosulfonate containing their oxidation and polymerization products (8) Curing the reaction solution prepared by adding lignosulfonate by heating (9) Use of the reaction solutions according to (2) and (7) for the coating of fertilizer granules (10) Processing of the reaction solutions according to (2) and (7) into plastic granules

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