Phosphoric Acids Research Articles

Soybean Nutrition in a Novel Single-Nutrient Source Hydroponic Solution

Hydroponic systems are efficient for studying plant nutrition. It is often desirable to adjust individual nutrients for unique species’ needs and/or to create multiple nutrient deficiencies within the same study. However, this is challenging to do with traditional solutions as nutrients are generally added as dual nutrient salts, such as when varying phosphorus (P) concentration also affects nitrogen concentration; potentially, the chemical form of the nutrient taken up when ammonium phosphate is the source for P. This can create unintended consequences with nutrients other than those intended for adjustment. A new hydroponic system has been created to allow for nutrient deficiencies using single-nutrient sources, including ammonium nitrate; phosphoric, sulfuric, hydrochloric, and boric acids; potassium, calcium, magnesium, zinc, and copper carbonates; manganese acetate; sodium molybdate; iron EDDHA; with HEDTA as an additional chelate. This nutrient solution was compared to a traditional “Hoagland” hydroponic solution to grow soybean (Glycine max (L.) Merr). Additional treatments included alteration of pH in the new solution as well as evaluating varying levels of calcium, magnesium, and manganese. This new solution proved effective, as soybean was grown to maturity and performed as well as the traditional Hoagland solution. Adjusting pH downward with hydrochloric acid resulted in healthy plants, but solution pH was not adequately buffered. Adjusting pH with acetic acid resulted in toxicity. Further work is required to provide better pH buffering and approximately align tissue nutrient concentrations with field-grown soybean.

Electrochemical and spectroscopic characterization of AgNP suspension stability influenced by strong inorganic acids

Silver nanoparticles are of utmost importance as functional material for inkjet printed electronics. Typically, to formulate inkjet-printable conductive ink, silver nanoparticles are synthesized, precipitated and dried, before being redispersed in an appropriate solvent mixture. For the precipitation step, usually relatively large quantities of organic solvents are required. In this work, we have studied the application of mineral acids, i.e. perchloric, sulfuric and phosphoric acids, as effective nanoparticle precipitants. The synthesized poly(acrylic acid) stabilized powdered product was characterized with FTIR, while the stabilities of the prepared dispersions were characterized by a novel approach via cyclic voltammetry, along with UV/Vis spectrophotometry. All of the investigated acids have shown to be promising candidates as precipitation agents. However, 0.01 M perchloric acid has shown a minimal effect on the surface stabilizer of the silver nanoparticles, thereby enabling highly effective conductive ink formulation with as-precipitated nanosilver.

Relation Between Adhesion Properties and Microscopic Characterization of Polyphosphoric Acid Composite SBS Modified Asphalt Binder

The purpose of this study was to investigate the adhesive properties of polyphosphoric acid compounded SBS (PPA/SBS) modified asphalt. Three base asphalt binders, one SBS, one dibutyl phthalate (DBP), one furfural extraction oil, and two polyphosphoric acids (PPA), were used to produce the modified binders. The adhesive properties tested in this study included contact angle, cohesive work, adhesive work, and peak area ratio. Cohesive work and adhesive work indicators were calculated from the contact angle, the contact angle between PPA/SBS modified asphalt and three liquids (distilled water, glycerin, formamide) were tested by the contact angle tester, and the peak area ratio of the microscopic adhesion performance index by AFM. The relation between the microscopic adhesion performance characterization method (peak area ratio) and the macroscopic adhesion performance index (cohesive work, adhesion work) was established. The test results indicated that the PPA/SBS modified asphalt had the highest cohesive work and adhesion work under the conditions of 0.5% PPA, 1% DBP, 1.5% extracted oil, and 3.5% SBS, which was clearly greater than the original SBS modified asphalt, while the peak area ratio was consistent with the cohesive work and adhesive work, in which the correlation coefficient between the peak area ratio and cohesive work was 0.77788, and that between the peak area ratio and adhesion work was 0.87203. We recommend adopting the peak area ratio to characterize PPA/SBS modified asphalt’s microscopic adhesion properties.

Complex processing of plant raw materials for furfural and glucose production

Data on the dynamics of furfural yield from wheat straw, corn cobs, birch sawdust, oat husk and sugar beet pulp in a narrow temperature range (180 – 190 ° C) were obtained. Low-concentrated solutions of sulfuric and phosphoric acids were used. Enzymatic hydrolysis of cellulosic residues was conducted. It was shown that the maximum yield of glucose in birch sawdust was 21.8%, in the corn cobs 18.6%, in wheat straw 19.4%, in sugar beet pulp 15.8 % of absolutely dry substance respectively.

Cyclic carbonates of rapeseed methyl esters as monomers for urethane composites

The two-stage synthesis of cyclic carbonates based on methyl esters of fatty acids from rapeseed oil is characterized. The first stage involves the synthesis of epoxides by the reaction of unsaturated methyl esters of rapeseed fatty acids with hydrogen peroxide, orthophosphoric and acetic acids. The second step is a carbonization reaction, which was carried out by passing carbon dioxide through the reactive mixture in the presence of tetrabutylammonium bromide as a catalyst. A reactive oligourethane based on cyclocarbonates cyclic carbonates of rapeseed fatty acids and piperazine was synthesized by the non-isocyanate method via the interaction of cyclocarbonate group with the amino group of piperazine. Polymer composites based on synthesized cyclocarbonates, epoxides and amines of different chemical nature were prepared and studied. Thus, there is a possibility of regulating the physical and mechanical properties of epoxyurethane composites.

Monolitik Zirkonya Materyalinin Dentine Bağlanma Dayanımı Üzerine Farklı Tür Asit Yüzey Uygulamalarının Etkilerinin Araştırılması

Objective: The aim of this study is to evaluate the effect of dentin surface treatments with citric, tartaric, phosphoric, and boric acids on the bonding strength of monolithic zirconia. Material and Methods: A hundred human molar teeth were randomly divided into subsets (n = 10) based on acid treatment modalities and thermocycling procedure. Monolithic zirconia superstructures were fabricated using CAD/CAM system in the final dimensions of 7 mm in diameter and 3 mm in thickness. After application of acid treatments to dentin surface, shear bond strength test was performed to assess the effectiveness of surface modifications that were also examined using a scanning electron microscope. Results: The study groups were ranked respectively as (citric acid>tartaric acid>phosphoric acid>boric acid>control) for the set of groups without thermocycling and (citric acid>tartaric acid) and (phosphoric acid>boric acid>control) for the set of thermocycling groups (p<0.05) based on highest value. The bonding strength of tartaric acid group was not significantly different from the bonding strength of phosphoric acid group (p>0.05). Conclusion: In both procedures with and without thermal cycling; based on order of efficacy, citric, tartaric, phosphoric, and boric acids were more effective in improving the shear bond strength between monolithic zirconia and dentin surface. The thermal cycling procedure decreased the bonding strength in all the groups.

Single-Crystalline Ultrathin 2D Porous Nanosheets of Chiral Metal-Organic Frameworks.

Two-dimensional (2D) materials with highly ordered in-plane nanopores are crucial for numerous applications, but their rational synthesis and local structural characterization remain two grand challenges. We illustrate here that single-crystalline ultrathin 2D MOF nanosheets (MONs) with intrinsic porosity can be prepared by exfoliating layered metal-organic frameworks (MOFs), whose layers are stabilized by sterically bulky groups. As a result, three three-dimensional (3D) isostructural lanthanide MOFs possessing porous layer structures are constructed by coordinating metal ions with an angular dicarboxylate linker derived from chiral 1,1'-biphenyl phosphoric acid with pendant mesityl groups. The Eu-MOF is readily ultrasonic exfoliated into single-crystalline nanosheets with a thickness of ca. 6.0 nm (2 layers) and a lateral size of 1.5 × 3.0 μm2. The detailed structural information, i.e., the pore channels and individual organic and inorganic building units in the framework, is clearly visualized by a low-dose high-resolution transmission electron microscopy (HRTEM) technique. Benefiting from their ultrathin feature, the nanosheets are well embedded into the polymer matrix to form free-standing mixed-matrix membranes. In both the solution and membrane phase, the fluorescence of the MONs can be effectively quenched by a total of 17 chiral terpenes and terpenoids through supramolecular interactions with uncoordinated chiral phosphoric acids, leading to a chiral optical sensor for detecting vapor enantiomers, which is among the most challenging molecular recognition tasks.

Development of Fluorescent Chemosensors for Amino‐Sugars

AbstractIn this account, we describe the application of a series of multidentate BINOL‐based phosphoric acids for the fluorescence‐based chemosensing of amino sugars. To this end, we developed a novel synthetic protocol for three isomerically pure phosphoric acid monoesters of the type ArOP(O)(OH)2. These were investigated with respect to their binding towards amino sugars (glucosamine, galactosamine and mannosamine) in comparison to the previously reported diesters of the type (ArO)2P(O)(OH). We could find that the diesters show no significant binding, while the monoesters can be used as hosts for amino sugars. Indeed, one host selectively binds to galactosamine, while a second host binds both glucosamine and mannosamine. This allows the fluorescence‐based detection and discrimination of the amino sugars by a novel class of phosphate‐based supramolecular hosts.

Insights on Molecular Characteristics of Hydrochars by 13C-NMR and Off-Line TMAH-GC/MS and Assessment of Their Potential Use as Plant Growth Promoters.

Hydrochar is a carbon-based material that can be used as soil amendment. Since the physical-chemical properties of hydrochar are mainly assigned to process parameters, we aimed at evaluating the organic fraction of different hydrochars through 13C-NMR and off-line TMAH-GC/MS. Four hydrochars produced with sugarcane bagasse, vinasse and sulfuric or phosphoric acids were analyzed to elucidate the main molecular features. Germination and initial growth of maize seedlings were assessed using hydrochar water-soluble fraction to evaluate their potential use as growth promoters. The hydrochars prepared with phosphoric acid showed larger amounts of bioavailable lignin-derived structures. Although no differences were shown about the percentage of maize seeds germination, the hydrochar produced with phosphoric acid promoted a better seedling growth. For this sample, the greatest relative percentage of benzene derivatives and phenolic compounds were associated to hormone-like effects, responsible for stimulating shoot and root elongation. The reactions parameters proved to be determinant for the organic composition of hydrochar, exerting a strict influence on molecular features and plant growth response.

Efficient methods for the synthesis of 1,2,3,4-tetrazine 1,3-dioxides annulated with five-membered polynitrogen heterocycles

New efficient methods were developed for the synthesis of heterocyclic 1,2,3,4-tetrazine 1,3-dioxides (TDOs) from appropriate amines based on the annulation with nitronium sulfates in organic solvents and also in HNO3 solutions using weak acid anhydrides. The synthesis of TDOs using P2O5 in an HNO3 solution requires the preliminary thermal decomposition of intermediate nitro(poly)phosphoric acids. The structure of 2-methyl-2H-[1,2,3]triazolo[4,5-e]-[1,2,3,4]tetrazine 1,5,7-trioxide was established by X-ray diffraction.

Dynamics of change of biochemical and functional-technological properties of lake’s trout meat in storage

The leading role in muscle contraction is played by myofibrils, which, from the substances that make up the sarcoplasm, use the necessary energy to perform their functions. The source of energy, in this case, is only the biochemical processes of enzymatic decomposition (hydrolysis, phosphorolysis) of certain substances, in particular, glycogen nucleoside phosphates, located mainly in the sarcoplasm. In the muscle tissue of fish, the bulk of the energy needed to contract muscles is released as a result of ATP breakdown. By the outward manifestation and chemistry of the processes, post mortem rigour Mortis is almost identical to the motor contraction of the living muscle. The molecular mechanism of muscle contraction is based on the interaction of myosin and actin filaments. Studies have shown that the intense breakdown of muscle glycogen leads to a sharp decrease in the pH of muscle tissue in the acidic direction, which in turn affects the chemical composition and physical and colloidal structure of proteins, resulting in increased resistance of fish meat to the action of putrefactive microorganisms; decreased solubility of muscle proteins, their hydration, water-binding ability; swelling of connective tissue collagen; increased activity causing hydrolysis of proteins in the later stages of autolysis; the bicarbonate system of muscle tissue is destroyed with the release of carbon dioxide; precursors of meat taste and aroma are formed; the process of lipid oxidation is activated. As a result of the accumulation of lactic, phosphoric and other acids in fish meat, the concentration of hydrogen ions increases resulting in a decrease in pH.

Chiral ligands for palladium-catalyzed asymmetric C–H activation

<p indent=0mm>Chiral ligands enabled palladium-catalyzed regio- and enantioselective C–H activation represents one of the current frontiers in transition metal catalysis. It has been extensively developed over the past decade as an important method for the synthesis of chiral molecules. Functional molecules bearing central, axial or planar chirality can be efficiently generated in good to excellent optical purities through this method. It has also been used as one of the most efficient methods for the rapid construction of various C–C and C–X bonds. In this review, we highlight the development of some representative chiral ligands in Pd-catalyzed enantioselective C(sp²)–H and C(sp³)–H functionalization reactions. Specifically, critical features of these novel Pd-catalyzed transformations assisted by chiral ligands such as monodentate phosphoramidites, chiral phosphoric acids (CPAs) and bifunctional mono-N-protected amino acids (MPAAs) will be discussed. The recent advances and limitations in this rapidly growing research area and its application in the total synthesis of natural products and pharmaceutical molecules will also be presented and discussed.

Mixed matrix membranes based on sodium alginate modified by fullerene derivatives with L-amino acids for pervaporation isopropanol dehydration

Biopolymer sodium alginate (SA) is actively used as a green membrane material. To improve the pervaporation properties of the SA membrane in the isopropanol dehydration, different water-soluble fullerene derivatives with L-amino acids (threonine, hydroxyproline, and arginine) were used. In this study, fullerene–arginine derivative (C60-Arg) was shown to be an optimal filler acting both as a modifier and a cross-linking agent for SA. Different cross-linking agents (phosphoric and citric acids, calcium chloride) were tested for dense membrane cross-linking to reinforce the membranes for the separation of diluted solutions. Two types of membranes based on SA and SA/C60-Arg (5%) were developed: dense and supported on polyacrylonitrile substrate. The structural features of obtained membranes were investigated by the following methods: FTIR spectroscopy, scanning electron (SEM), and atomic force (AFM) microscopies. The optimal transport properties in dehydration of isopropanol (12–100 wt.% water) were found for the cross-linked SA/C60-Arg (5%) membrane supported on PAN substrate. The following parameters were obtained: 0.5–4.7 kg/(m2h) permeation flux and constant 99.99 wt.% water content in the permeate.

MEMBRANE MATERIALS BASED ON POROUS ANODIC ALUMINIUM OXIDE

Anodized aluminum oxide (AOA) is applied in many technological areas such as formation of decorative or anticorrosive coating, hydrophobic and hydrophilic surfaces, development of functional micro- and nanomaterials. Due to unique properties of porous structure (most direct, regular and through pores with size in a narrow range) AOA films can be used for membrane separation. The morphological features of such films mainly depend on synthesis conditions. This review consists of the models of pore formation on the aluminum surface and the correlation parameters of films with anodizing conditions. Particular attention is paid to the influence of synthesis factors (electrolyte composition, voltage, temperature conditions, etc) on the porous structure of AOA and the film thickness that determines the mechanical strength of membranes. The optimal voltage values for the porous structure arraingment of anodized aluminum oxide were indicated for each electrolyte. It is noted formation of cylindrical shaped pores with controllable pore diameters, periodicity and density distribution can be produced during two-stage anodizing. The pre-treatment of the metal surface and stage of separation of the formed film from its surface are also considered. Modern research are mainly aimed to synthesis of porous AOA membranes in new anodizing electrolytes and determining pore formation factors on the aluminum surface. The new anodizing conditions in most popular electrolytes (oxalic, sulfuric, phosphoric acids) for obtaining of porous AOA with the required morphological features is also under investigation. Such conditions include, for example, a lower voltage or higher temperature in case for a particular electrolyte. To avoid of local heating the electrolytes with additional components, for example, organic additives is also studied. Some practical aspects of AOA membrane utilization obtained under certain conditions are considered.

Markedly Different Decomposition Temperature and Products of Biomass Pyrolysis at Low Temperature—Differentiation of Acids in Their Effects on Pretreatment

Pine as a softwood and poplar as a hardwood pretreated with hydrochloric acid (HCl), phosphoric acid (H3PO4), and hypophosphorous acid (H3PO2) are studied for the pyrolytic properties and products in thermogravimetry (TG) and fixed bed reactor. The pyrolysis performances are pronouncedly distinguished due to the compositional and structural changes induced by the acid pretreatments. Reduction in the mineral content in the biomass feedstocks by pretreatment with the acids results in significant changes in the pyrolytic products. The residual P in the H3PO2-pretreated biomass apparently catalyzed the biomass deeper dehydration in pyrolysis compared to the other two mineral acids. TG analysis shows a shift of the temperature of maximum mass loss (Tmax) by more than 40 °C to lower temperature in the decomposition of the H3PO2-pretreated biomass from that of the untreated and the HCl- and H3PO4-pretreated biomass. Inspired by the striking differences in TG profiles of biomass pretreated by the three acids, thermal pyrolysis of pretreated biomass was carried out in a fixed bed reactor aimed at producing biochemicals at low temperatures (330 °C and 400 °C). The liquid products obtained from the fixed bed reactor show remarkably different major anhydrosugars as a result of pretreatment by the three acids. While phenolics dominate in the collected pyrolysis liquid from untreated biomass samples, biomass pretreated with all three acids results in substantially reduced phenolics in the bio-oils. The reduction in phenolic compounds in the bio-oil may be attributed to the reduction in mineral content in the feedstock. Consequently, the yields of anhydrosugars, mainly levoglucosan (LG) and levoglucosenone (LGO) are increased. LG yields of 20.9–28.5% from the cellulose content are obtained from HCl- and H3PO4-pretreated pine/poplar, with very low LGO yield (less than 1.7%). However, H3PO2-pretreated biomass is selective to produce LGO, especially at 330 °C. LGO yields of 7.4% and 6.7% are obtained from H3PO2-pretreated pine and poplar, respectively.

Dye removal kinetics and adsorption studies of activated carbon derived from the stems of Phyllanthus reticulatus

The research work is oriented towards the preparation of an adsorbent carbon from Phyllanthus reticulatus plant to remove reactive orange 16 dye (RO 16) from aqueous media. The prepared carbon was activated (PRAC) using a mixture of nitric and phosphoric acids. The surface morphology and amorphous/crystalline nature of PRAC were assessed using scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis respectively. The adsorption capacity of PRAC was measured by performing a batch mode adsorption study with reference to pH, temperature, PRAC dose and RO 16 concentration and the maximum dye adsorption was found to be 85.10%. The observed adsorption isotherm and kinetic model for the chosen adsorbent-adsorbate system seemed to be Langmuir and pseudo-second-order respectively. The measured changes that occurred in entropy (ΔSo), Gibbs free energy (ΔGo) and enthalpy (ΔHo) revealed that RO 16 uptake was spontaneous and exothermic.

REMOVAL OF URANIUM AND ASSOCIATED ELEMENTS FROM SINAI WELLS WATER USING THE DRIED AND CHEMICALLY MODIFIED ORANGE PEELS

It is well known that the natural cellulose has low ionic exchange properties, due to its characterization by a small number of carboxylic groups. Incorporation of different functional groups can promote its ionic exchange capacity. In this work, modification of orange peel by treating with sodium hydroxide and amination, phosphoration and sulfonation. The different ion exchanger has been used to increase the ion exchange capacity of such materials, by developing their swelling properties and decreasing their lignin content. A maximum uranium uptake of 726 mg/g was observed at the obtained optimum conditions using modified resin (ion exchange No. VII). The latter (0.841: 0.420) mm size orange peels were modified using a mixture of sulfonic and phosphoric acids. Ion exchange No. VII was used as the case study to remove uranium and associated elements from Sinai wells water. The main purpose of this work is to prepare different resins from the Egyptian plant waste. Orange peels were chosen because they are popular and widespread plant wastes in Egypt.

Deactivation of Materials and Articles in the Presence of Silver(II)

Experimental results are presented to substantiate conditions and modes of the process of deactivation of materials and articles to remove the surface α-, and γ-radioactive contamination. Compositions of a deactivating solution based on a mixture of nitric and phosphoric acids with addition of divalent silver, which enable a 102–103-fold decrease in the surface radioactive contamination in one deactivation cycle at room temperature. A scheme of silver regeneration for its repeated use was developed. The scheme provides a silver yield of about 95% with a ~105 coefficient of purification to remove radioactive isotopes.

N-Triflylphosphoramides: highly acidic catalysts for asymmetric transformations.

N-Triflylphosphoramides (NTPA), have become increasingly popular catalysts in the development of enantioselective transformations as they are stronger Brønsted acids than the corresponding phosphoric acids (PA). Their highly acidic, asymmetric active site can activate difficult, unreactive substrates. In this review, we present an account of asymmetric transformations using this type of catalyst that have been reported in the past ten years and we classify these reactions using the enantio-determining step as the key criterion. This compendium of NTPA-catalysed reactions is organised into the following categories: (1) cycloadditions, (2) electrocyclisations, polyene and related cyclisations, (3) addition reactions to imines, (4) electrophilic aromatic substitutions, (5) addition reactions to carbocations, (6) aldol and related reactions, (7) addition reactions to double bonds, and (8) rearrangements and desymmetrisations. We highlight the use of NTPA in total synthesis and suggest mnemonics which account for their enantioselectivity.

Quasi-Two-Dimensional Sky-Blue Perovskite Light-Emitting Devices Enhanced by Hypophosphorous Acid Incorporation

Quasi-Two-Dimensional Sky-Blue Perovskite Light-Emitting Devices Enhanced by Hypophosphorous Acid Incorporation