WO2019150382A1

WO2019150382A1 - A method for preparation of othro silicic acid for agriculture

Info

Publication number: WO2019150382A1
Application number: PCT/IN2018/000058
Authority: WO
Inventors: Vijay Kumar Doppalapudi; Gopal Bhagwan DEORE
Original assignee: Privi Life Science Private Limited
Priority date: 2018-01-30
Filing date: 2018-12-18
Publication date: 2019-08-08

Abstract

The present invention relates to a method for preparation of Ortho Silicic acid only for agriculture. The present invention uses Phosphonic acid / Phosphorus acid which is a very active molecule in plant which itself triggers SAR mechanism in the plants.

Description

A METHOD FOR PREPARATION OF ORTHO SILICIC ACID FOR

AGRICULTURE

FIELD OF INVENTION:

The present invention relates to the field of stabilized solution of ortho- silicic acid (H₄S1O₄). The present invention in particular relates to a method for preparation of Ortho Silicic acid as a free flowing liquid having long shelf life.

DESCRIPTION OF THE RELATED ART:

Silicon (Si) is important biogenic microelement which exhibits several roles in human, plant and animal organism. In plants, silicon exhibits the following effects [H. A. Currie, C. C. Perry: Silica in Plants: Biological, Biochemical and Chemical Studies, Ann. Botany 100 - (2007) 1383-1389]: (i) stimulates photosynthesis process and increases utility of nutrients what results in enhanced crop yields; (ii) improves water management and thus enhances resistance to stress conditions like drought; and (iii) enhances resistance to insect attacks and fungal diseases.

Biologically available source of silicon is ortho-silicic acid (H Si ). It is known to those skilled in the art that silicic acid, in its monomeric form, ortho-silicic acid (H₄S1O₄) is not stable, but at higher concentrations undergoes polymerization yielding dimeric (H S O ) , trimeric (HsShOio) , as well as linear unbranched oligomers (SI) which are all water soluble.

It is known from practice and literature that appropriately treated silicon compounds become compounds which are assimilated by plants. Silicic acid particles in colloidal solutions are characterised by a large surface, of approximately 300 m² per 1 ml of solution. As active silanol Si-OH hydrophilic groups are observed on their surface, such molecules have a tendency to separate from the water and clump together to form larger agglomerates, which reduces their water solubility and hinders their uptake by plants. The addition of organic compounds, such as polysaccharides, polyalcohols and amino acids, stabilises silicate solutions against undesired polymerisation, increasing their bioavailability. Methods have been developed to provide silicic acid in various forms.

Reference may be made to the following-

US5922360 relates to a preparation comprising ortho silicic acid which is stabilized with a stabilizing agent and is substantially free of organic silicon compounds, preferably a nitrogen-containing stabilizing agent such as choline, to a method for preparing such a preparation, comprising: i) providing a solution containing a stabilizing agent; ii) dissolving an inorganic silicon compound in the solution containing the stabilizing agent; and iii) hydrolyzing the silicon compound to ortho silicic acid, and to the obtained biological preparation.

US3514402 relates to a synthetic lubricant esters of the disilicic acid ester type having the formula (SiDAO-Si)-(OR)„(OR') wherein A is a polymethylol- carboxylic acid ester of the structural formula: CH2— CH2 wherein Z is the ester residue of said carboxylic acid and R is hydrogen or a lower alkyl of about 1 to 6 carbon atoms, R is alkyl, R' is diethylene glycol-n-butyl ether residue, R and R may be the same or diiferent, and n is to 3.

Publication No. WO2012035364 relates a stabilized solution of ortho- silicic acid consisting of: (i) ortho-silicic acid (H4Si04), from 0.01-8% w/w; (ii) carnitine salt (1) of pharmaceutically acceptable acids, formula (1), X= Cl , H₂P0₄, H₂S0₄, HNO₃, CH₃SO₃, C₆H₅SO₃, 1 , 4-CH₃C₆H₄SC>₃ from 7-40% w/w; (iii) pharmaceutically acceptable acid, from 0.05-4 molar equivalents to H Si0₄; (iv) auxiliary stabilizer of H₄Si0 , selected from the group comprising: glycerol, 1. 2- propylene glycol, d-panthenol, glucosamine, or their mixtures, from 10-50% w/w; and (v) diluent, selected from the group consisting of purified water, ethanol, or their mixtures, in amounts of up to 100% w/w of overall formulation.

Publication No. WO2012032364 relates to a formulation that serves as a highly bioavailable silicon (Si) source consisting of: (i) ortho-silicic acid (H₄Si0 ), from 0.01-8% w/w; (ii) salicylic acid (1), from 1-2 molar equivalents to H Si0₄; (iii) pharmaceutically acceptable acid, from 0.1 -4 molar equivalents to H₄Si0₄; or pharmaceutically acceptable base, in amounts of 2 molar equivalents to salicylic acid (1); and (iv) diluent, selected from the group consisting of: purified water, 1, 2-propylene glycol, glycerol, ethanol, or their mixtures, in amounts of up to 100% w/w of the formulation.

Publication No. US20030099676 relates to a method for preparing ortho silicic acid wherein an acid hydrolysable silicon compound is hydrolysed in an acid solution in the presence of a non toxic solvent agent under the formation of ortho silicic acid, wherein preferably the ortho silicic acid formed is contacted with a non toxic particulate carrier, and to the use of a silicon preparation in the production of animal feed, food, food or feed supplement, and of a pharmaceutical or cosmetic preparation.

Publication No. WO1995021124 relates to a preparation comprising ortho silicic acid which is stabilized with a stabilizing agent and is substantially free of organic silicon compounds, preferably a nitrogen-containing stabilizing agent such as choline, to a method for preparing such a preparation, comprising: i) providing a solution containing a stabilizing agent; ii) dissolving an inorganic silicon compound in the solution containing the stabilizing agent; and iii) hydrolyzing the silicon compound to ortho silicic acid, and to the obtained biological preparation.

Publication No. WO2014185794 relates to the silicon formulation with plant growth stimulating properties, containing water-soluble compounds of silicon, in the form of an aqueous solution or powdery water-soluble substance contains water-soluble silicon compounds in an amount of 0.5 to 60% by weight (calculated as Si0₂), dissolved in an aqueous medium in the presence of polysaccharides, polyalcohols, fulvic acids, amino acids or mixtures thereof, and additionally preferably contains at least one of the macro and/or micronutrients such as nitrogen, phosphorus, potassium, magnesium, calcium, sulphur, boron, copper, iron, manganese, molybdenum, zinc, cobalt. Silicic acids, potassium silicates, sodium silicates, or mixtures thereof are the source of silicon compounds, while the pH of the silicon compounds used in the formulation is from 2 to 13. Preferably the formulation contains mannitol, sorbitol, betaine, methionine, glycine or mixtures thereof in an amount of 0.1 to 10 % by weight. Publication No. 2202/CHE/2009 relates to a composition of micro colloidal silicic acid and a method of preparing the composition that comprises of an aqueous solution of micro colloidal silicic acid, an aqueous solution of high concentration of water absorbing additives, an acidified solution of water with a strong acid having pH less than 1 and boric acid.

Hence, present invention aims to provide a method for preparation of ortho silicic acid (OSA) as a free flowing liquid having long shelf life.

OBJECTS OF THE INVENTION:

The principal object of the present invention is to provide a method for preparation of stabilized ortho silicic acid as a free flowing liquid for agriculture.

Another object of the present invention is to provide a method for preparation of ortho silicic acid in nano form.

Yet another object of the present invention is to provide a method for preparation of ortho silicic acid having long shelf life.

Still another object of the present invention is to provide a method for preparation of ortho silicic acid that is stable at room temperature.

SUMMARY OF THE INVENTION:

The present invention relates to a method for preparation of ortho silicic acid for agriculture. The method comprises the steps - distilled water and Phosphonic acid / Phosphorus acid, which is a solid and highly soluble in water is charged. The pH of this solution does not go below 2.0, as it acts like a buffer. To this solution pure fulvic acid is added. This solution is called as super charged Phosphorus.

Inorganic acid which is solid and highly solubilizes and it can not be consumed by plant unless it oxidisizes to Phosphate is used to generate ortho silicic acid from Silicates at pH as low as 2-4 and then stabilisized with organic acids like Fulvic acid as a dissociating agent which dissociates the polymerized silicic acid acids back to monomer and. then natural polymers is_. added with high hydroxyl value such as without limitation natural polyphenols, antioxidants such as without limitation pyrroloquinoline quinone.

BREIF DESCRIPTION OF THE INVENTION:

It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered for limiting of its scope, for the invention may admit to other equally effective embodiments.

Figure 1 (a), (b) shows impact on the plant growth after two weeks of applications Figure 2 shows comparative graphical representation of fruits per plant in chillies (hot pepper) after 28 days of application of different treatments as listed. T l : OSA (choline chloride), T2: OSA (PEG) + Phosphorous acid (0.4%) + FA (0.2%), T3: OSA (PEG) + Phosphorous acid (0.4%) + FA (0.2%) + PQQ (5 ppm).

DETAILED DESCRIPTION OF THE INVENTION:

The present invention relates to a method for preparation of ortho silicic acid for agriculture. The method comprises the steps - distilled water and Phosphonic acid / Phosphorus acid which is a solid and highly soluble in water is charged. The pH of this solution does not go below 2.0, as it acts like a buffer. To this solution pure fulvic acid is added. This solution is called as super charged Phosphorus.

Inorganic acid, which is solid and highly solubilizes and it can not be consumed by plant unless it oxidisizes to phosphate is used to generate ortho silicic acid from silicates at pH as low as 2-4 and then stabilisized with organic acids like fulvic acid as a dissociating agent which dissociates the polymerized silicic acid acids back to monomer and then natural polymers is added with high hydroxyl value such as without limitation natural polyphenols, antioxidants such as without limitation pyrroloquinoline quinone.

The phosphonic acid of 99% is taken in the reactor and heated and maintained between 120 -150 C for 4 hours so that the bonded. Moisture is removed and polymerized to form an active super charged phosphorus and then the DM water is added to bring phosphorus concentration of 5 - 20 %.

Meanwhile solution of potassium silicate 5-20% is prepared in the other reactor and this solution is added into the solution of super charged Phosphorus till the colour changes to light yellow. A sample is drawn and the particle size is analysed, then a mixture of natural polyphenol, natural antioxidants and PEG-400 is added and after that zinc oxide, molybdenum, boron are added. The particle size of the solution is analysed till it becomes around 60-80 nm. The solution is heated to 50°C and cooled. The finally prepared solution always remains a free flowing liquid and has minimum shelf life of 3 years at room temperature i.e. at 25°C.

Phosphonic. acid/ phosphorus acid is a very active molecule in plant which itself triggers systemic acquired resistance (SAR) mechanism in the plants so with natural antioxidant the phosphorous acid does not get oxidized because of natural fulvic acid and other co factors like pyrroloquinolinequinone (PQQ) which is a potent antioxidant so these two ingredients trigger induced systemic resistance inside the plant. Thus the orthosilicic acid formulation is active inside the plant for longer time period.

The invention is described in detail with reference to the examples given below. The examples are provided just to illustrate the invention and therefore, should not be construed to limit the scope of the invention.

EXAMPLES

Example 1: Impact of various ingredients on growth and phytotoxicity

Twenty five-day old transplanted plants were sprayed with varied doses of components viz. fulvic acid (FA; 0.05% and 0.3%), Phosphorous acid (0.2% and 0.5%), and pyrroloquinolinequinone (PQQ; 2 ppm and 5 ppm). Silicic acid stabilized using choline chloride (@ 0.2% and 0.5%) and water spray served as control for all these treatments. Other crop practices and fertilizer applications were same for all treatments. Plants were evaluated for various physiological and agronomical parameters. The mean temperature ranged from 28-35 °C with 60-70 % RH. All pots were filled with 5 kg of soil and were irrigated with tap water on alternate days. lmpact on growth attributes

Foliar applications of different products exhibited a differential impact on agronomic traits is shown in figure 1 where Tl : Control (water spray), T2:

Phosphorous acid (0.2 %), T3: Phosphorous acid (0.5%), T4: Fulvic acid

(FA) (0.05%), T5: Fulvic acid (0.3%), T6: PQQ (2 ppm); T7:PQQ (5 ppm),

T8: Choline Cl stabilized OSA (0.2%), T9: Choline Cl stabilized OSA

(0.5%).

An increase in various growth parameters were recorded following application of fulvic acid and PQQ compared to control. Application of phosphorous/phosphoric acid and fulvic acid at tested doses had improved the development of lateral roots over control. Choline chloride stabilized ortho silicic acid, when used at higher dose had exhibited a plateauin response for almost all the parameters recorded.

Phvtotoxicitv of foliar sprays

PEG stabilized OSA, where HC1 was used as a catalyst or choline chloride stabilized OSA had exhibited scorching impact on leaves when sprayed at higher doses (Table2). While no phytotoxicity was recorded for when phosphoric/phosphorous acid was used as a catalyst along with fulvic acid and PQQ, either alone or in combination at all tested concentrations.

Table 2: Phytotoxicity of different doses of components following foliar application after 48 hours

The process for stabilization of ortho silicic acid using PEG as a stabilizer and Phosphoric/ Phosphorous acid / combination of two as catalyst along with FA and PQQ has ensured the use of product even at high concentration without any phtyotoxicity, thus facilitating its usage through ultra-low volume sprayers.

Example 2: Synergistic impact of above mentioned components with ortho silicic acid stabilized with PEG 400

Experiments were conducted in the field on chillies (hot pepper) on commercially popular variety (Nandita). Crop was raised in the open field with black soil, having drip-irrigation facility. The mean temperature ranged from 29-40°C with 35-50% RH. Agronomical parameters along with yield attributes were recorded after one month of application (Table 3). Different combinations of ingredients to PEG stabilized OSA, has attenuated theyield of crop besides improving the growth related traits (Fig 2). A significant increase in the fruit number per plant was recorded in all treatments over standalone choline OSA. Among all treatments, combination of all i.e. OSA. Phosphoric acid, FA and PQQ has been identified as best under field conditions. Figure 2: Comparative graphical representation of fruits per plant in chillies (hot pepper) after 28 days of application of different treatments as listed. Tl : OSA (choline chloride), T2: OSA (PEG) + Phosphorous acid (0.4%) + FA (0.2%), T3: OSA (PEG) + Phosphorous acid (0.4%) + FA (0.2%) + PQQ (5 ppm).

Table 3: Impact of different products when applied as foliar spray along with OSA stabilized using choline chloride. All values indicated are percentage increaise recorded 28 days application

Example 3: Improved nutrient use efficacy

Synergistic interaction between Silicon and phosphorous is well documented. We foresee that adopting the process as described here would improve the uptake of phosphorus from soil fertilized with any phosphorous sources (Mono ammonium phosphate (MAP)/ Di ammonium Phosphate (DAP), Single super phosphate (SSP), Tri super phosphate (TSP)). A study was conducted to ascertain this interaction. Rice plants were sprayed with test products (Tl : OSA (choline chloride) and T2: OSA (PEG) + Phosphorous acid (0.4%)+ FA (0.2%) + PQQ (5 ppm)was sprayed on 25-day after transplanting and leaves were collected one week after analyses of Phosphorus content. DAP was applied as basal dose.

A substantial improvement in leaf phosphorous content was recorded among different treatments, with 3 g/Kg and 5.2 g/kg of Phosphorous in treatment 1 and 2, respectively.

Example 4: improved tolerance against biotic stress

To ascertain this impact of phosphorous acid and PQQ, artificial inoculation of blast {Pyricularia oryza) was done in rice. Spores suspension (@lX10⁶ spore/ml) were sprayed twice after 30 days and 50 days of transplanting. The test products (Tl : OSA choline chloride, T2: OSA (PEG) + Phosphorous acid (0.4%) + FA (0.2%), T3: OSA (PEG) + Phosphorous acid (0.4%) + FA (0.2%) + PQQ (5 ppm), T4: Tricyclazole @ 0.6 g/1, T5: Control (water spray) were sprayed after 7 days of spraying of spore application. Observations were recorded at harvest on terminal disease severity of leaf and neck blast.

Foliar application of T2 and T3 considerably reduced disease severity indicating their role in alleviation of biotic stress (Table 4). Maximum disease severity was recorded in control (water spray), while least in tricyclazole treated plots.

Table 4: Efficacy of combinations on blast severity in rice following artificial inoculation

Example 5: lmproved tolerance against abiotic stress

An analysis was conducted in vitro where osmotic stress was induced by using PEG 600- at 15% concentration on 30-day-old wheat seedlings. Various physiological and biochemical parameters (viz. seedling weight, leaf water content, relative electrolyte leakage and lipid peroxidation) were recorded to ascertain the impact of.different treatments Tl: OSA choline chloride, T2: OSA (PEG) + Phosphorous acid (0.4%) + FA (0.2%), T3: OSA (PEG) + Phosphorous acid (0.4%) + FA (0.2%) + PQQ( 5 ppm), T4: Control (PEG 6000) in alleviating stress. All treatments were having osmotic stress imposed byPEG 600.

The experimental data on various parameters as listed in Table 5 and 6 clearly indicate that addition of PQQ in PEG stabilized OSA has a distinct role in alleviating the osmotic stress.

Table 5: Impact of formulations on physiological parameters under osmotic stress

Table 6: Impact of formulations on membrane stability and leakiness parameters under osmotic stress

Example 6: Impact of addition of different ingredients . on the stability of the formulation

Zeta potential meter was used to ascertain the particle size of the formulation. Analysis was done for samples stored under ambient conditions as well as in accelerated ageing at 52°C. Zeta Potential is used as a measurement for assessing the dispersion stability of colloidal systems. Higher values are indicative of stable dispersions due to electrostatic repulsion between particles while if the zeta potential approaches zero, the stability of dispersion reduces thereby increasing chances aggregate formation. Table 7 demonstrates that addition of dissociating agents viz. FA, PQQ, GA in the formulation has improved the zeta potential reading substantially, thus indicating formation of more stable dispersions (Table 7). Maintenance of colloidal solution in dispersive nature for longer period of time is an indicator for enhanced efficacy of product/formulation.

Table 7 Zeta Potential readings of the products, following incubation at ambient temperatures

Thus the new process of stabilization of OSA described herein has ensured the development of efficacious product with extended shelf life. Products of OSA have been made using different recipes using PEG 400 as a stabilizer having Phosphoric/ phosphorous acid / poly phosphoric acid/pyrophosphoric acid/in combinations (@ 20-50%) as catalyst; fulvic acid (FA; 5-30%) and PQQ (2000- 5000 ppm) as a dissociating agent. Natural polysaccharides (viz.gum Arabica, GA) has also been used in the formulation for extended the shelf life

Numerous modifications and adaptations of the system of the present invention will be apparent to those skilled in the art, and thus it is intended by the appended claims to cover all such modifications and adaptations which fall within the true spirit and scope of this invention.

Claims

WE CLAIM:

1. An Ortho Silicic Acid (OSA) and its method of preparation for agriculture includes following steps:

a) Charging distilled water and Phosphonic acid / Phosphorus acid wherein the pH of this solution is above 2.0

b) Adding pure fulvic acid to this solution

c) Generating Ortho Silicic acid from Inorganic acid Silicates at pH as low as 2-4

d) Stabilisizing with organic acids like Fulvic acid as a dissociating agent e) Dissociation of the Polymerized Silicic acid acids back to Monomer f) Adding natural polymers with high Hydroxyl value

g) Heating the phosphonic acid of 99% between 120 - 150 C for 4 hours h) Adding the DM Water to bring Phosphorus Concentration of 5 - 20 %. i) Adding solution of Potassium silicate 5-20% into the solution of super charged Phosphorus till the colour changes to light yellow.

j) Adding a mixture of Natural Polyphenol, Natural Antioxidants and PEG- 400 and after that Zinc oxide, Molybdenum, Boron.

k) Heating the solution to 50°C and cooled.

2. The Ortho Silicic Acid (OSA), as claimed in any of the preceding claims, wherein the said solution always remains a free flowing liquid and has minimum shelf life of 3 years at room temperature i.e. at 25°C.

3. The Ortho Silicic Acid (OSA), as claimed in any of the preceding claims, wherein the said Phosphonic acid / Phosphorus acid triggers systemic acquired resistance (SAR) mechanism in the plants so with natural antioxidant the Phosphorus acid does not get oxidized because of natural fulvic acid and other co factors which are a potent antioxidant so these two ingredients trigger induced systemic resistance inside the plant and the orthosilicic acid formulation is active inside the plant for longer time period.

4. The Ortho Silicic Acid (OSA), as claimed in any of the preceding claims, wherein polysaccharides such as without limitation gum Arabica, (GA) has been used for extended the shelf life