cas 7664-38-2, Orthophosphoric acid | Articles data

Articles about 7664-38-2Total 81 be found

Article title
Article abstract
Author
Journal number and time
Download

Oxidative hydroxylation of phosphine in aqueous alcohol solutions of p-benzoquinone
The oxidation of phosphine in aqueous alcohol solution of benzoquinone in the presence of iodide ions is studied. Kinetic measurements, redox potentiometry, and gas chromatography are used to determine the kinetic regularities of the oxidative hydroxylati
Polimbetova,Borangazieva,Ibraimova, Zh. U.,Ergozhin,Mukhitdinova
(2014)
Read Online

-
-
Gulland,Walsh
p. 169,171
(1945)
Read Online

Thermal transformations of Co(H2PO4)2·2H2O
Thermal transformations of Co(H2PO4)2·2H2O in air, vacuum, water-vapor atmosphere were studied by the methods of DTA, XRD, paper chromatographic analyses and gravimetry. It was established that the removal of th
Lukyanchenko,Samuskevich
p. 181 - 189
(1999)
Read Online

A continuous enzyme-coupled assay for triphosphohydrolase activity of HIV-1 restriction factor SAMHD1
The development of deoxynucleoside triphosphate (dNTP)-based drugs requires a quantitative understanding of any inhibition, activation, or hydrolysis by off-target cellular enzymes. SAMHD1 is a regulatory dNTP-triphosphohydrolase that inhibits HIV-1 replication in human myeloid cells. We describe here an enzyme-coupled assay for quantifying the activation, inhibition, and hydrolysis of dNTPs, nucleotide analogues, and nucleotide analogue inhibitors by triphosphohydrolase enzymes. The assay facilitates mechanistic studies of triphosphohydrolase enzymes and the quantification of off-target effects of nucleotide-based antiviral and chemotherapeutic agents.
Arnold, Laurence H.,Kunzelmann, Simone,Webb, Martin R.,Taylor, Ian A.
p. 186 - 192
(2015)
Read Online

Reactivity of free and CoIII-co-ordinated phosphite; mechanisms of bromine oxidation and H/D exchange
The complexes t- and p-[Co(tren)(NH3){OP(H)(O)2}]ClO4 (1·ClO4 and 2-ClO4, respectively) and syn(OP(H)(O)2), anti(OH2)-[Co(cyclen)(OH2){OP(H)(O)2}]ClO 4
Carrington, Sonya J.,Buckingham, David A.,Simpson, Jim,Blackman, Allan G.,Clark, Charles R.
p. 3809 - 3816
(1999)
Read Online

H3PO3 electrochemical behaviour on a bulk Pt electrode: adsorption and oxidation kinetics
Polybenzimidazole-type polymer doped with H3PO4 is commonly used as the proton-conductive phase in high-temperature proton-exchange membrane fuel cells. However, H3PO4 is not stable during fuel cell operation and undergoes reduction by hydrogen on a Pt surface to phosphorus compounds in a lower oxidation state, such as H3PO3. In this work the kinetics of H3PO3 oxidation on Pt electrode was studied, including an investigation of H4P2O6 as a possible oxidation intermediate. H3PO3 adsorption in hydrogen underpotential deposition region was described by a triple Langmuir isotherm corresponding to adsorption on specific Pt crystalline planes. Co-adsorption of hydrogen as well as SO42?, HSO4? ions decreased the total amount of adsorbed H3PO3. The determined apparent charge transfer coefficients of H3PO3 anodic oxidation on a metallic Pt surface were found to be concentration and temperature-dependent, indicating that the nature of the anodic process is complex. From chronopotentiometric measurements of H3PO3 and H4P2O6 oxidation on a preoxidised Pt surface it was concluded that, while H3PO3 is oxidised by means of a chemical reaction with PtOx, H4P2O6 undegoes anodic oxidation on the PtOx surface. According to voltammetry and bulk electrolysis experiments H4P2O6 is not formed as an intermediate product during electrochemical oxidation of H3PO3 on a metallic Pt surface.
Prokop,Bystron,Paidar,Bouzek
p. 465 - 472
(2016)
Read Online

PhnY and PhnZ comprise a new oxidative pathway for enzymatic cleavage of a carbon-phosphorus bond
The sequential activities of PhnY, an α-ketoglutarate/Fe(II)- dependent dioxygenase, and PhnZ, a Fe(II)-dependent enzyme of the histidine-aspartate motif hydrolase family, cleave the carbon-phosphorus bond of the organophosphonate natural product 2-aminoethylphosphonic acid. PhnY adds a hydroxyl group to the α-carbon, yielding 2-amino-1-hydroxyethylphosphonic acid, which is oxidatively converted by PhnZ to inorganic phosphate and glycine. The PhnZ reaction represents a new enzyme mechanism for metabolic cleavage of a carbon-phosphorus bond.
McSorley, Fern R.,Wyatt, Peter B.,Martinez, Asuncion,Delong, Edward F.,Hove-Jensen, Bjarne,Zechel, David L.
p. 8364 - 8367
(2012)
Read Online

Efficient hydrolytic cleavage of phosphodiester with a lanthanide-based metal-organic framework
Hydrolysis of phosphate diesters has attracted substantial research efforts, not only in bio-organic chemistry, but also in inorganic chemistry. Herein, a lanthanide-based metal-organic framework was synthesized by incorporating a tetraphenylethylene moiety as the four-point connected node, Ce-TCPE (noted as 1). The structural analyses indicate that 1 exhibits 3D framework connected by the sharing carboxylate groups with two kinds of 1D rhombic channels when viewed along the c direction. Hydrolytic cleavage catalysis have been performed and showed that 1 could act as efficient heterogeneous catalyst for the hydrolytic cleavage of the phosphodiester BNPP (bis(p-nitrophenyl)phosphate) with the high activity and hydrolytic stability in a pseudo-first-order rate. DFT studies has also gain an insight analysis to elucidate the cleavage process.
Dong, Yunhui,Dou, Yong,Qin, Lan,Yang, Lu,Zhang, Daopeng,Zhou, Zhen
(2020/11/09)

Hydrolysis of element (White) phosphorus under the action of heterometallic cubane-type cluster {mo3pds4}
Reaction of heterometallic cubane-type cluster complexes—[Mo3{Pd(dba)}S4Cl3(dbbpy)3]PF6, [Mo3{Pd(tu)}S4Cl3(dbbpy)3]Cl and [Mo3{Pd(dba)}S4/s
Babaev, Vasily M.,Gushchin, Artem L.,Khayarov, Khasan R.,Kuchkaev, Aidar M.,Kuchkaev, Airat M.,Shmelev, Nikita Y.,Sinyashin, Oleg G.,Sokolov, Maxim N.,Sukhov, Aleksandr V.,Yakhvarov, Dmitry G.
(2021/05/28)

Synthesis, crystal structure, IR, Raman spectroscopy, and DFT computation of metacarboxyphenyl ammonium dihydrogenomonophosphate (C7H4NH3OOH) H2PO4(m-C AMP)
The metacarboxyphenyl ammonium dihydrogenomonophosphate (C7H4NH3OOH) H2PO4 was synthesized and studied by a combination of single-crystal X-ray diffraction analysis, infrared, Raman vibrational spectroscopy, and density functional computation (DFT) calculation. This compound crystallizes in the monoclinic system, with the central space group P21/c. Its unit-cell dimensions are a = 12.9361 (7) (?), b = 11.7735 (6) (?), c = 6.5764 (4) (?), β = 102.668° (2), and V = 977.22 (9) ?3.The structure determined gives a clear description of the hydrogen bonds connecting the hydrogen phosphate H2PO4– with the organic matrix. The atomic arrangement of this compound is built up by symmetric (H4P2O8)2– dimers anions formed by two (H2PO4)– via hydrogen bonding O1—H…O3. Each (H2PO4)– aggregates with cation through hydrogen bond interactions of O–H…O(P) and N–H…O(P) types. The bands observed in the infrared and Raman spectra of (C7H4NH3OOH) H2PO4 are assigned based on the results obtained in the literature and based on the computational group analyses performed in the factor group C2h. Besides, the optimal molecular geometry, harmonic vibration frequencies, infrared intensities, and Raman scattering activities were calculated using the DFT approach performed with the Gaussian 09 program using the hybrid function B3LYP combining the three Becke parameters and the Lee-Yang-Parr exchange-correlation function using the 6-311 + G(d,p) base set. The highest occupied molecular orbital–lowest unoccupied molecular orbital properties and geometries of this compound were determined and discussed. The results of the calculated structural parameters are generally in agreement with the experimental investigations. The computational infrared and Raman spectra of the reference compound have been constructed.
Belaaouad, Said,Chtita, Samir,El Makhloufy, Smail,Majdi, El Mehdi
(2021/08/12)

Synthesis, Stability, and Kinetics of Hydrogen Sulfide Release of Dithiophosphates
The development of chemicals to slowly release hydrogen sulfide would aid the survival of plants under environmental stressors as well as increase harvest yields. We report a series of dialkyldithiophosphates and disulfidedithiophosphates that slowly degrade to release hydrogen sulfide in the presence of water. Kinetics of the degradation of these chemicals were obtained at 85 °C and room temperature, and it was shown that the identity of the alkyl or sulfide group had a large impact on the rate of hydrolysis, and the rate constant varied by more than 104×. For example, using tert-butanol as the nucleophile yielded a dithiophosphate (8) that hydrolyzed 13,750× faster than the dithiophosphate synthesized from n-butanol (1), indicating that the rate of hydrolysis is structure-dependent. The rates of hydrolysis at 85 °C varied from a low value of 6.9 × 10-4 h-1 to a high value of 14.1 h-1. Hydrogen sulfide release in water was also quantified using a hydrogen sulfide-sensitive electrode. Corn was grown on an industrial scale and dosed with dibutyldithiophosphate to show that these dithiophosphates have potential applications in agriculture. At a loading of 2 kg per acre, a 6.4% increase in the harvest yield of corn was observed.
Bowden, Ned B.,Brown, Eric M.,Paudel, Arjun,Ranasinghe Arachchige, Nimesh P. R.
p. 12900 - 12908
(2021/11/17)

Tunable pH-sensitive 2-carboxybenzyl phosphoramidate cleavable linkers
We previously described a pH-sensitive phosphoramidate linker scaffold that can be tuned to release amine-containing drugs at various pH values. In these previous studies it was determined that the tunability of this linker was dependent upon the proximity of an acidic group (e.g., carboxylic acid or pyridinium). In this study, we confirmed that the tunability of pH-triggered amine-release was also dependent upon the pKa of the proximal acidic group. A series of 2-carboxybenzyl phosphoramidates was prepared in which the pKa of the proximal benzoic acid was predictably attenuated by substituents on the benzoate ring consistent with their σ-values.
Backer, Brian S.,Berkman, Clifford E.,Browne, Zachery S.,Choy, Cindy J.,Davis, Austen L.
supporting information

(2020/02/15)

PROCESS FOR RECOVERING PHOSPHORIC ACID FROM SOLID PHOSPHORUS SOURCES
The invention pertains to a process for preparing phosphoric acid from a solid phosphorus-containing material, comprising the steps of: - reacting a solid phosphorus-containing material with strong acid in an amount of 1.0-15 mole acid, calculated as protons, per mole of phosphorus (calculated as P) in the solid phosphorus-containing material in a monophasic reaction medium comprising an organic solvent, to form a solution of phosphoric acid in organic solvent and remaining solid material, - separating the solution of phosphoric acid in organic solvent from the remaining solid material. It has been found that phosphoric acid can be recovered from a solid phosphorus-containing material in high purity and efficiency via a solid-state rearrangement/elution process. The process according to the invention does not require the use of the large amounts of water required by the conventional dissolution/extraction processes known in the art. The solution of phosphoric acid in organic solvent can be used as a starting material for further processes.
-
Page/Page column 10-12; 14-17

(2020/09/08)

Degradation of tri(2-chloroisopropyl) phosphate by the UV/H2O2 system: Kinetics, mechanisms and toxicity evaluation
A photodegradation technology based on the combination of ultraviolet radiation with H2O2 (UV/H2O2) for degrading tri(chloroisopropyl) phosphate (TCPP) was developed. In ultrapure water, a pseudo-first order reaction was observed, and the degradation rate constant reached 0.0035 min?1 (R2 = 0.9871) for 5 mg L?1 TCPP using 250 W UV light irradiation with 50 mg L?1 H2O2. In detail, the yield rates of Cl? and PO43? reached 0.19 mg L?1 and 0.58 mg L?1, respectively. The total organic carbon (TOC) removal rate was 43.02%. The pH value of the TCPP solution after the reaction was 3.46. The mass spectrometric detection data showed a partial transformation of TCPP into a series of hydroxylated and dechlorinated products. Based on the luminescent bacteria experimental data, the toxicity of TCPP products increased obviously as the reaction proceeded. In conclusion, degradation of high concentration TCPP in UV/H2O2 systems may result in more toxic substances, but its potential application for real wastewater is promising in the future after appropriate optimization, domestication and evaluation.
He, Huan,Ji, Qiuyi,Gao, Zhanqi,Yang, Shaogui,Sun, Cheng,Li, Shiyin,Zhang, Limin
(2019/07/31)

Mechanism of methylphosphonic acid photo-degradation based on phosphate oxygen isotopes and density functional theory
Methylphosphonic acid (MPn) is an intermediate in the synthesis of the phosphorus-containing nerve agents, such as sarin and VX, and a biosynthesis product of marine microbes with ramifications to global climate change and eutrophication. Here, we applied the multi-labeled water isotope probing (MLWIP) approach to investigate the C-P bond cleavage mechanism of MPn under UV irradiation and density functional theory (DFT) to simulate the photo-oxidation reaction process involving reactive oxygen species (ROS). The results contrasted with those of the addition of the ROS-quenching compounds, 2-propanol and NaN3. The degradation kinetics results indicated that the extent of MPn degradation was more under alkaline conditions and that the degradation process was more rapid at the initial stage of the reaction. The phosphate oxygen isotope data confirmed that one exogenous oxygen atom was incorporated into the product orthophosphate (PO4) following the C-P bond cleavage, and the oxygen isotopic composition of this free PO4 was found to vary with pH. The combined results of the ROS-quenching experiments and DFT indicate that the C-P bond was cleaved by OH-/OH and not by other reactive oxygen species. Based on these results, we have established a mechanistic model for the photolysis of MPn, which provides new insights into the fate of MPn and other phosphonate/organophosphate compounds in the environment.
Xia, Congcong,Geng, Huanhuan,Li, Xiaobao,Zhang, Yiyue,Wang, Fei,Tang, Xiaowen,Blake,Li, Hui,Chang, Sae Jung,Yu, Chan
p. 31325 - 31332
(2019/10/19)

Characterization of Dialkyldithiophosphates as Slow Hydrogen Sulfide Releasing Chemicals and Their Effect on the Growth of Maize
Hydrogen sulfide is a key gasotransmitter for plants and has been shown to greatly increase their growth and survival in the presence of environmental stressors. Current methods for slowly releasing hydrogen sulfide use chemicals, such as GYY-4137, but these result in the release of chemicals not found in the environment, and chemicals used may lack structures that can be readily tuned to affect the rate of release of hydrogen sulfide. In this article, we describe the synthesis and slow release of hydrogen sulfide from dialkyldithiophosphates, which are a new set of hydrogen sulfide releasing chemicals that can be used in agriculture. The rates of hydrolysis of dibutyldithiophosphate and GYY-4137 were measured in water at 85 °C and compared with each other to investigate their differences. GYY-4137 is widely used as a chemical that slowly releases H2S, but its rate of release was not previously quantified. The release of hydrogen sulfide in water at room temperature was measured for a series of dialkyldithiophosphates using a hydrogen sulfide electrode. It was shown that the structure of the dialkyldithiophosphate affected the amount of hydrogen sulfide released. The final degradation products of dibutyldithiophosphate were shown to be phosphoric acid and butanol, which are chemicals found in the environment. This result was notable because it demonstrated that dialkyldithiophosphates degrade to safe, natural chemicals that will not pollute the environment. To demonstrate that dialkyldithiophosphates have potential applications in agriculture, maize was grown for 4.5 weeks after exposure to 1-200 mg of dibutyldithiophosphate, and the weight of corn plants increased by up to 39% at low loadings of dibutyldithiophosphate.
Carter, Justin M.,Brown, Eric M.,Irish, Erin E.,Bowden, Ned B.
(2019/11/03)

Regulating Higher-Order Organization through the Synergy of Two Self-Sorted Assemblies
The extracellular matrix (ECM) is the natural fibrous scaffold that regulates cell behavior in a hierarchical manner. By mimicking the dynamic and reciprocal interactions between ECM and cells, higher-order molecular self-assembly (SA), mediated through the dynamic growth of scaffold-like nanostructures assembled by different molecular components, was developed. Designed and synthesized were two self-sorted coumarin-based gelators, a peptide molecule and a benzoate molecule, which self-assemble into nanofibers and nanobelts, respectively, with different dynamic profiles. Upon the dynamic growth of the fibrous scaffold assembled from peptide gelators, nanobelts assembled from benzoate gelators transform into a layer-by-layer nanosheet, reaching ninefold increase in height. By using light and an enzyme, the spatial–temporal growth of the scaffold can be modified, leading to in situ height regulation of the higher-order architecture.
Ji, Wei,Zhang, Shijin,Yukawa, Sachie,Onomura, Shogo,Sasaki, Toshio,Miyazawa, Kun'ichi,Zhang, Ye
supporting information
p. 3636 - 3640
(2018/03/06)

Substrate Specificity and Chemical Mechanism for the Reaction Catalyzed by Glutamine Kinase
Campylobacter jejuni, a leading cause of gastroenteritis worldwide, has a unique O-methyl phosphoramidate (MeOPN) moiety attached to its capsular polysaccharide. Investigations into the biological role of MeOPN have revealed that it contributes to the pathogenicity of C. jejuni, and this modification is important for the colonization of C. jejuni. Previously, the reactions catalyzed by four enzymes (Cj1418-Cj1415) from C. jejuni that are required for the biosynthesis of the phosphoramidate modification have been elucidated. Cj1418 (l-glutamine kinase) catalyzes the formation of the initial phosphoramidate bond with the ATP-dependent phosphorylation of the amide nitrogen of l-glutamine. Here we show that Cj1418 catalyzes the phosphorylation of l-glutamine through a three-step reaction mechanism via the formation of covalent pyrophosphorylated (Enz-X-Pβ-Pγ) and phosphorylated (Enz-X-Pβ) intermediates. In the absence of l-glutamine, the enzyme was shown to catalyze a positional isotope exchange (PIX) reaction within β-[18O4]-ATP in support of the formation of the Enz-X-Pβ-Pγintermediate. In the absence of ATP, the enzyme was shown to catalyze a molecular isotope exchange (MIX) reaction between l-glutamine phosphate and [15N-amide]-l-glutamine in direct support of the Enz-X-Pβintermediate. The active site nucleophile has been identified as His-737 based on the lack of activity of the H737N mutant and amino acid sequence comparisons. The enzyme was shown to also catalyze the phosphorylation of d-glutamine, γ-l-glutamyl hydroxamate, γ-l-glutamyl hydrazide, and β-l-aspartyl hydroxamate, in addition to l-glutamine.
Taylor, Zane W.,Chamberlain, Alexandra R.,Raushel, Frank M.
p. 5447 - 5455
(2018/09/25)

Substrate Specificity and Chemical Mechanism for the Reaction Catalyzed by Glutamine Kinase
Campylobacter jejuni, a leading cause of gastroenteritis worldwide, has a unique O-methyl phosphoramidate (MeOPN) moiety attached to its capsular polysaccharide. Investigations into the biological role of MeOPN have revealed that it contributes to the pathogenicity of C. jejuni, and this modification is important for the colonization of C. jejuni. Previously, the reactions catalyzed by four enzymes (Cj1418-Cj1415) from C. jejuni that are required for the biosynthesis of the phosphoramidate modification have been elucidated. Cj1418 (l-glutamine kinase) catalyzes the formation of the initial phosphoramidate bond with the ATP-dependent phosphorylation of the amide nitrogen of l-glutamine. Here we show that Cj1418 catalyzes the phosphorylation of l-glutamine through a three-step reaction mechanism via the formation of covalent pyrophosphorylated (Enz-X-Pβ-Pγ) and phosphorylated (Enz-X-Pβ) intermediates. In the absence of l-glutamine, the enzyme was shown to catalyze a positional isotope exchange (PIX) reaction within β-[18O4]-ATP in support of the formation of the Enz-X-Pβ-Pγintermediate. In the absence of ATP, the enzyme was shown to catalyze a molecular isotope exchange (MIX) reaction between l-glutamine phosphate and [15N-amide]-l-glutamine in direct support of the Enz-X-Pβintermediate. The active site nucleophile has been identified as His-737 based on the lack of activity of the H737N mutant and amino acid sequence comparisons. The enzyme was shown to also catalyze the phosphorylation of d-glutamine, γ-l-glutamyl hydroxamate, γ-l-glutamyl hydrazide, and β-l-aspartyl hydroxamate, in addition to l-glutamine.
Taylor, Zane W.,Chamberlain, Alexandra R.,Raushel, Frank M.
(2018/09/21)

An Unusual Two-Step Hydrolysis of Nerve Agents by a Nanozyme
Organophosphate-based nerve agents irreversibly inhibit acetylcholinesterase enzyme, leading to respiratory failure, paralysis and death. Several organophosphorus hydrolases are capable of degrading nerve agents including pesticides and insecticides. Development of stable artificial enzymes capable of hydrolysing nerve agents is important for the degradation of environmentally toxic organophosphates. Herein, we describe a Zr-incorporated CeO2 nanocatalyst that can be used for an efficient capture and hydrolysis of nerve agents such as methyl paraoxon to less toxic monoesters. This unusual sequential degradation pathway involves a covalently linked nanocatalyst-phosphodiester intermediate.
Khulbe, Kritika,Roy, Punarbasu,Radhakrishnan, Anusree,Mugesh, Govindasamy
p. 4840 - 4845
(2018/09/27)

Oxidation of white phosphorus by peroxides in water
A mixture of hypophosphorous, phosphorous, and phosphoric acids is formed during the anaerobic oxidation of white phosphorus by peroxides [ROOН; R = Н, 3-ClC6H4CO, (СН3)3С] in water. The rate of reactions grows considerably upon adding nonpolar organic solvents. The activity series of peroxides and solvents are determined experimentally. NMR spectroscopy shows that the main product of the reaction is phosphorous acid, regardless of the nature of the peroxide and solvent. A radical mechanism of oxidation of white phosphorus by peroxides in water is proposed. It is initiated by the homolysis of peroxide with the formation of НO? radicals that are responsible for the homolytic opening of phosphoric tetrahedrons. Further oxidation and stages of the hydrolysis of intermediate phosphorus-containing compounds yield products of the reaction.
Abdreimova,Akbaeva,Polimbetova
p. 1873 - 1876
(2017/09/27)

Reactivity of phosphine oxide H3PO in the reactions with ketones
The reactivity of the electrochemically generated phosphine oxide H3PO towards ketones (acetone, ethyl methyl ketone, methyl n-propyl ketone, and tert-butyl methyl ketone) has been studied. It was found that this reaction led to the formation o
Gorbachuk,Badeeva,Babaev,Rizvanov, I. Kh.,Zinnatullin,Pavlov,Khayarov, Kh. R.,Yakhvarov
p. 1289 - 1294
(2017/02/05)

FLUORINE-CONTAINING PHOSPHATE ESTER-AMIDE, AND FLAME RETARDANT RESIN, FLAME RETARDANT LIQUID AND FLAME RETARDANT SOLVENT FOR ORANIC SYNTHESIS CONTAINING SAME
[Problem] To provide a fluorine-containing phosphate ester-amide which has high flame retardancy such as exhibiting flame retardant effects at a small quantity of addition, and sufficient hydrolysis resistance. [Solution] A fluorine-containing phosphate ester-amide represented by general formula (1). (In the formula, R1 and R2 are the same or different and represent a branched or linear alkyl group having 1 to 20 carbon atoms in which at least one carbon bonded to a nitrogen atom is a secondary or tertiary carbon, wherein R1 and R2 may have a substituent group selected from the group consisting of an alkoxy group, a hydroxy group, an amino group, a methyl amino group, an ethyl amino group, a dimethyl amino group, diethyl amino group and a fluorine atom. In addition, R1 and R2 may be bonded together to form a five- to eight-membered cyclic structure. X and Y are the same or different and represent a hydrogen atom or a fluorine atom, and n and m represent an integer of 1 to 6.)
-
Paragraph 0057; 0059

(2015/03/03)

Textile/metal-organic-framework composites as self-detoxifying filters for chemical-warfare agents
Abstract The current technology of air-filtration materials for protection against highly toxic chemicals, that is, chemical-warfare agents, is mainly based on the broad and effective adsorptive properties of hydrophobic activated carbons. However, adsorption does not prevent these materials from behaving as secondary emitters once they are contaminated. Thus, the development of efficient self-cleaning filters is of high interest. Herein, we report how we can take advantage of the improved phosphotriesterase catalytic activity of lithium alkoxide doped zirconium(IV) metal-organic framework (MOF) materials to develop advanced self-detoxifying adsorbents of chemical-warfare agents containing hydrolysable P-F, P-O, and C-Cl bonds. Moreover, we also show that it is possible to integrate these materials onto textiles, thereby combining air-permeation properties of the textiles with the self-detoxifying properties of the MOF material. The silk of human kindness: Insertion of lithium alkoxides in zirconium metal-organic frameworks (MOF) which are then deposited on silk fibers gives rise to protective fabrics capable of self-detoxifying chemical-warfare agents. The fabrics combine the air-permeation properties of the textiles with the highly active phosphotriesterase catalytic activity of the MOF for the hydrolysis of P-F, P-O, and C-Cl bonds.
L?pez-Maya, Elena,Montoro, Carmen,Rodríguez-Albelo, L. Marleny,Aznar Cervantes, Salvador D.,Lozano-Pérez, A. Abel,Cenís, José Luis,Barea, Elisa,Navarro, Jorge A. R.
supporting information
p. 6790 - 6794
(2015/06/08)

Crystal structure of PhnZ in complex with substrate reveals a di-iron oxygenase mechanism for catabolism of organophosphonates
The enzymes PhnY and PhnZ comprise an oxidative catabolic pathway that enables marine bacteria to use 2-aminoethylphosphonic acid as a source of inorganic phosphate. PhnZ is notable for catalyzing the oxidative cleavage of a carbon-phosphorus bond using Fe(II) and dioxygen, despite belonging to a large family of hydrolytic enzymes, the HD-phosphohydrolase superfamily. We have determined high-resolution structures of PhnZ bound to its substrate, (R)-2-amino-1-hydroxyethylphosphonate (2.1 A), and a buffer additive, L-tartrate (1.7 A). The structures reveal PhnZ to have an active site containing two Fe ions coordinated by four histidines and two aspartates that is strikingly similar to the carbon- carbon bond cleaving enzyme, myo-inositol-oxygenase. The exception is Y24, which forms a transient ligand interaction at the dioxygen binding site of Fe2. Site-directed mutagenesis and kinetic analysis with substrate analogs revealed the roles of key active site residues. A fifth histidine that is conserved in the PhnZ subclade, H62, specifically interacts with the substrate 1-hydroxyl. The structures also revealed that Y24 and E27 mediate a unique induced-fit mechanism whereby E27 specifically recognizes the 2- amino group of the bound substrate and toggles the release of Y24 from the active site, thereby creating space for molecular oxygen to bind to Fe2. Structural comparisons of PhnZ reveal an evolutionary connection between Fe(II)-dependent hydrolysis of phosphate esters and oxidative carbon-phosphorus or carbon- carbon bond cleavage, thus uniting the diverse chemistries that are found in the HD superfamily.
Van Staalduinen, Laura M.,McSorley, Fern R.,Schiessl, Katharina,Séguin, Jacqueline,Wyatt, Peter B.,Hammerschmidt, Friedrich,Zechel, David L.,Jia, Zongchao
p. 5171 - 5176
(2014/05/06)

Catalytic zinc complexes for phosphate diester hydrolysis
Creating efficient artificial catalysts that can compete with biocatalysis has been an enduring challenge which has yet to be met. Reported herein is the synthesis and characterization of a series of zinc complexes designed to catalyze the hydrolysis of phosphate diesters. By introducing a hydrated aldehyde into the ligand we achieve turnover for DNA-like substrates which, combined with ligand methylation, increases reactivity by two orders of magnitude. In contrast to current orthodoxy and mechanistic explanations, we propose a mechanism where the nucleophile is not coordinated to the metal ion, but involves a tautomer with a more effective Lewis acid and more reactive nucleophile. This data suggests a new strategy for creating more efficient metal ion based catalysts, and highlights a possible mode of action for metalloenzymes.
Tirel, Emmanuel Y.,Bellamy, Zoe,Adams, Harry,Lebrun, Vincent,Duarte, Fernanda,Williams, Nicholas H.
supporting information
p. 8246 - 8250
(2014/08/18)

Discovery of a cyclic phosphodiesterase that catalyzes the sequential hydrolysis of both ester bonds to phosphorus
The bacterial C-P lyase pathway is responsible for the metabolism of unactivated organophosphonates under conditions of phosphate starvation. The cleavage of the C-P bond within ribose-1-methylphosphonate-5-phosphate to form methane and 5-phospho-ribose-1,2-cyclic phosphate (PRcP) is catalyzed by the radical SAM enzyme PhnJ. In Escherichia coli the cyclic phosphate product is hydrolyzed to ribose-1,5-bisphosphate by PhnP. In this study, we describe the discovery and characterization of an enzyme that can hydrolyze a cyclic phosphodiester directly to a vicinal diol and inorganic phosphate. With PRcP, this enzyme hydrolyzes the phosphate ester at carbon-1 of the ribose moiety to form ribose-2,5-bisphosphate, and then this intermediate is hydrolyzed to ribose-5-phosphate and inorganic phosphate. Ribose-1,5-bisphosphate is neither an intermediate nor a substrate for this enzyme. Orthologues of this enzyme are found in the human pathogens Clostridium difficile and Eggerthella lenta. We propose that this enzyme be called cyclic phosphate dihydrolase (cPDH) and be designated as PhnPP.
Ghodge, Swapnil V.,Cummings, Jennifer A.,Williams, Howard J.,Raushel, Frank M.
p. 16360 - 16363
(2013/12/04)

METHODS OF TREATING CANCER USING 3-(5-AMINO-2-METHYL-4-OXO-4H-QUINAZOLIN-3-YL)-PIPERIDINE-2,6-DIONE
Provided herein are methods of treating, preventing and/or managing cancers, which comprise administering to a patient 3-(5-amino-2-methyl-4-oxo-4H-quinazolin-3-yl)-piperidine-2,6-dione, or an enantiomer or a mixture of enantiomers thereof, or a pharmaceutically acceptable salt, solvate, hydrate, co-crystal, clathrate, or polymorph thereof.
-
(2012/09/22)

The first water-soluble tetraphosphorus ruthenium complex. Synthesis, characterization and kinetic study of its hydrolysis
Reaction of the water-soluble complex [CpRu(TPPMS)2Cl] (1) [TPPMS = sodium salt of m-monosulfonated triphenylphosphine, Ph 2P(m-C6H4SO3Na)] with 1 equiv of white phosphorus in the presence of TlPFsub
Caporali, Maria,Gonsalvi, Luca,Kagirov, Rustam,Mirabello, Vincenzo,Peruzzini, Maurizio,Sinyashin, Oleg,Stoppioni, Piero,Yakhvarov, Dmitry
p. 67 - 73
(2012/09/10)

Kinetics and pathways for an algal phospholipid (1,2-dioleoyl-sn-glycero-3- phosphocholine) in high-temperature (175-350 °c) water
We examined the behavior of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) in high-temperature water at 175, 200, 225, and 350 °C. DOPC hydrolyzed to give oleic acid and a number of phosphorus-containing products. The hydrolysis was catalyzed by oleic and phosphoric acids, which were also reaction products. DOPC formed 1-acyl and 2-acyl lyso-phosphatidylcholine (LPC) along with oleic acid as primary products. LPC subsequently formed other phosphorus-containing intermediates, which finally led to phosphoric acid as the ultimate P-containing product. At 350 °C, phosphoric acid and oleic acid were the only products observed. We observed an ester of oleic acid and glycerol (9-octadecenoic-2,3- dihydroxypropyl ester), which likely formed via the hydrolysis of LPC. A reaction network is proposed to explain the formation of the observed products. A quantitative kinetics model based on the proposed pathways was consistent with the experimental data.
Changi, Shujauddin,Savage, Phillip E.,Matzger, Adam J.
p. 2856 - 2867,12
(2020/09/14)

Raman- and infrared-spectroscopic investigations of dilute aqueous phosphoric acid solutions
Phosphoric acid in water and heavy water has been studied by Raman and infrared spectroscopy over a broad concentration range (0.00873-1.560 mol kg-1) at 23 °C. The vibrational modes of the PO4 skeleton (C3v symmetry) of H3PO4(aq) and D 3PO4(D2O) have been assigned. In addition to the P-O stretching modes a deformation mode has been detected, δPO-H(D) at 1250 and 935 cm-1, respectively. In addition to the modes of the phosphoric acid and heavy phosphoric acid a mode of the dissociation product H2PO4- and D2PO4 - has been detected at 1077 cm-1 and 1084 cm-1 respectively. H3PO4 and D3PO4 is hydrated in aqueous solution which could be verified by Raman spectroscopy following the νPO and νsP(OH)3 mode as a function of temperature. These modes show a pronounced temperature dependence inasmuch as νPO shifts to higher wavenumbers with temperature increase and νsP(OH)3 to lower wavenumbers. In the range between 300-600 cm-1 the deformation modes have been observed. In very dilute H3PO4 solutions however, the dissociation product is the dominant species. The dissociation degree, α for H3PO 4(aq) and D3PO4(D2O) as a function of dilution has been measured at 23 °C. In these dilute H3PO 4(aq) and D3PO4(D2O) solutions no spectroscopic features for a dimeric species of the formula H6P 2O8 and D6P2O8 could be detected. Quantitative Raman measurements have been carried out to follow the dissociation of H3PO4 and D3PO4 over a very broad concentration range and also as a function of temperature. From the dissociation data, the pK1 value for H3PO4 has been determined to 2.14(1) and for D3PO4 to 2.42(1) at 23 °C. In the temperature interval from 24.5 to 99.7 °C the pK 1 values for H3PO4(aq) have been determined and thermodynamic data have been derived.
Rudolph, Wolfram W.
p. 9642 - 9653
(2011/01/10)

Oxidation of lower oxyacids of phosphorus by tetraethylammonium chlorochromate: A kinetic and mechanistic study
Oxidation of lower oxyacids of phosphorus by tetraethylammonium chlorochromate in dimethyl sulphoxide leads to the formation of corresponding oxyacids with phosphorus in a higher oxidation state. The reaction exhibits 1:1 stoichiometry. The reaction is first order each with respect to chlorochromate and the oxyacids. The reaction does not induce polymerization of acrylonitrile. The oxidation of deuterated phosphinic and phosphorous acids exhibits a substantial primary kinetic isotope effect. The oxidation has been studied in nineteen different organic solvents. The effect of solvent indicates that the solvent polarity plays a major role in the process. It has been shown that the pentacoordinated tautomer of the phosphorus oxyacid is the reactive reductant and the tricoordinated form of phosphorus oxyacids does not participate in the oxidation process. A mechanism involving transfer of a hydride ion in the rate determining step has been proposed.
Vadera, Khushboo,Sharma,Agarwal,Sharma, Pradeep K.
p. 302 - 306
(2011/01/10)

Activation and transformation of white phosphorus by palladium(ii) complexes
A reaction of bis(triphenylphosphine)palladium dibromide with white phosphorus in the presence of NaBPh4 selectively gives phosphorous acid H3PO3. The mechanism of the formation involves coordination of a white phosphorus molecule, ligand exchange, and hydrolysis of the coordinated P4 molecule in the coordination sphere of palladium.
Kagirov,Voloshin,Rizvanov, I. Kh.,Sinyashin,Yakhvarov
p. 1116 - 1118
(2011/02/16)

Aqueous inks containing colored polymers
Disclosed is an ink composition comprising (a) an aqueous liquid vehicle, and (b) a colorant which comprises an anhydride copolymer having at least one chromogen covalently bonded thereto and at least one ester, amide, imide, or thioester group covalently bonded thereto, said colorant being soluble or dispersible in the aqueous liquid vehicle. Also disclosed is an ink composition comprising (a) an aqueous liquid vehicle, and (b) a colorant which is the reaction product of (1) an anhydride copolymer, (2) a chromogen having one and only one group per molecule selected from the group consisting of —OH, —SH, primary amino, and secondary amino, and (3) a material selected from the group consisting of nonchromogenic monofunctional alcohols, nonchromogenic monofunctional thiols, nonchromogenic monofunctional primary or secondary amines, and mixtures thereof, said colorant being soluble or dispersible in the aqueous liquid vehicle.
-
(2009/04/24)

Kinetics and mechanism of electron transfer reactions: Oxidation of glyoxylic acid by peroxomonophosphoric acid in acid perchlorate medium
The kinetics of oxidation of glyoxylic acid by peroxomonophosphoric acid in acidic medium is reported here. The stoichiometry corresponds to the reaction of one mole of peroxomonophosphate for one mole of glyoxylic acid. The reaction is second order (first order with respect to each reactant). The suggested rate law corresponds to the plausible reaction mechanism.
Vijai,Mala,Khandelwal,Sharma
p. 859 - 862
(2009/02/06)

Method for preparing melamine salt of pentaerypolyol phosphoric acid
A method for preparing a melamine salt of pentaerypolyol phosphoric acid is provided. The method comprises the following steps of: ball milling a mixture of pentaerypolyol and phosphorus pentoxide (P2O5) under a solvent-free reacting environment to obtain a pentaerypolyol phosphoric acid, and ball milling a mixture of a pentaerypolyol phosphoric acid and melamine without organic solvent reacting environment to obtain a melamine salt of pentaerypolyol phosphoric acid.
-
Page/Page column 5

(2008/06/13)

Method of preparing ionic liquids
In the process for preparing ionic liquids, an ionic liquid is firstly reacted with an alkoxide or with barium hydroxide and is subsequently neutralized with an acid. The ionic liquid contains a phosphonium and/or ammonium cation and an anion selected from the group consisting of halides, arylsulfonates, alkylsulfonates, sulfate, hydroxysulfate, alkylsulfates, hydrogencarbonate, carbonate. triflate and carboxylates. In this process, virtually any anions can be introduced into the ionic liquids.
-
(2008/06/13)

Imidazolium-Methyl Sulfites for Use as Starting Compounds for Producing Ionic Liquids
Imidazolium methylsulfites of the general formula (I) where the radicals have, independently of one another, the following meanings: R1 to R3: hydrogen, halogen, hydroxy, amino, aminocarbonyl, sulfo, cyano, nitro; C1-C20-alkyl, C2-C20-alkenyl, C2-C20-alkynyl, C1-C20-alkyloxy, C2-C20-alkenyloxy, C2-C20-alkynyloxy, C1-C20-alkylcarbonyl, C1-C20-alkyloxycarbonyl, C1-C20-acyloxy, C1-C20-alkylaminocarbonyl, di(C1-C20-alkyl)aminocarbonyl, C1-C20-alkylamino, di(C1-C20-alkyl)amino, C1-C20-alkylsulfonyl, C3-C8-cycloalkyl, where the alkyl, alkenyl, alkynyl and cycloalkyl groups mentioned can be substituted and/or have their CH2 groups replaced by oxygen; phenyl, phenoxy, where these can in turn be substituted; R4: sulfo; C1-C20-alkyl, C2-C20-alkenyl, C2-C20-alkynyl, C3-C8-cycloalkyl, where the alkyl, alkenyl, alkynyl and cycloalkyl groups mentioned can be substituted and/or have their CH2 groups replaced by oxygen; phenyl, where this can be substituted; or R1 together with R4, and/or R2 together with R3, or R4 together with R2: alkylene —(CH2)n— where n=4, 5 or 6 or butadienylene —CH═CH—CH═CH—, where these can be substituted and/or have the CH2 groups replaced by oxygen and the CH groups replaced by NR5.
-
(2008/06/13)

Process for the preparation of N-phosphonomethylglycine and derivatives thereof
N-phosphonomethylamines are produced by reaction of an amine substrate with a halomethylphosphonic acid or salt thereof, a hydroxymethylphosphonic acid or salt thereof, or a dehydrated self-ester dimer, trimer or oligomer of hydroxymethylphosphonic acid. Among the products that may be prepared according to the process are N-phosphonomethylaminocarboxylic acids such as (e.g.) glyphosate, N-phosphonomethylaminoalkanols such as (e.g.) hydroxyethlaminomethylphosphonic acid, and N-acylaminomethylphosphonic acids such as (e.g.) N-carbamylaminomethylphosphonic acid. Certain reactions are conducted with a substantial excess of amine reactant in order to drive the conversion while avoiding excessive formation of bis(N-phosphonomethyl)amine by-products. Other reactions use a secondary amine substrate (such as iminodiacetic acid) and can be conducted at substantial equimolar ratios of halomethylaminomethylphosphonic acid or hydroxyaminomethylphosphonic acid to secondary amine reactant without significant formation of bis(phosphonomethyl)amine by-products. Further disclosed is a process for the preparation of hydroxymethylphosphonic acid self-ester dimers, trimers and oligomers by azeotropic dehydration.
-
Page/Page column 30

(2010/02/11)

Boranophosphate salts as an excellent mimic of phosphate salts: Preparation, characterization, and properties
We report on the preparation of boranophosphate salts, BPi (2), and the exploration of their properties with a view to developing a new mimic of the parent phosphate. BPi salts were easily prepared in excellent yield in a one-pot two-step reaction from tris(trimethylsilyl) phosphite, and were characterized by X-ray crystallography and IR, 1H and 31P NMR spectroscopy. We evaluated the acid/base character of BPi by determining its acidity constants. Likewise, we evaluated the stability of BPi at various pH values, and calculated the decomposition-rate constants at highly acidic pH. We also monitored the H-bonded clustering of BPi in organic solvents, including MeOH. Finally, we explored the chemical behavior of BPi with respect to various organic and inorganic reagents. BPi is stable under the following conditions: both basic and acidic pH (pH > 2), in the presence of amines, and in the presence of Mg2+ ions. However, a P-B bond cleavage is observed upon the reaction of BPi with carbodiimides or upon catalytic hydrogenation. The reducing nature of the BH3 moiety is drastically decreased in BPi. Likewise, the nucleophilicity of BPi's oxygen atom is lower than in phosphate, Pi, salts. Based on its water solubility, acid-base character, and H-bonding properties, BPi appears as a perfect mimic of Pi and is an attractive alternative to the known phosphate isosters. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.
Nahum, Victoria,Fischer, Bilha
p. 4124 - 4131
(2007/10/03)

Method and compositions for identifying anti-HIV therapeutic compounds
Methods are provided for identifying anti-HIV therapeutic compounds substituted with carboxyl ester or phosphonate ester groups. Libraries of such compounds are screened optionally using the novel enzyme GS-7340 Ester Hydrolase. Compositions and methods relating to GS-7340 Ester Hydrolase also are provided.
-
(2008/06/13)

Aqueous speciation studies of europium(III) phosphotungstate
The incorporation of lanthanide ions into polyoxometalates may be a unique approach to generate new luminescent, magnetic, and catalytic functional materials. To realize these new applications of lanthanide polyoxometalates, it is imperative to understand the solution speciation chemistry and its impact on solid-state materials. In this study we find that the aqueous speciation of europium(III) and the trivacant polyoxometalate, PW9O 349-, is a function of pH, countercation, and stoichiometry. For example, at low pH, the lacunary (PW11O 39)7- predominates and the 1:1 Eu(PW11O 39)4-, 2, forms. As the pH is increased, the 1:2 complex, Eu(PW11O39)211- species, 3, and (NH4)22{(Eu2PW10O38) 4(W3O8(H2O)2(OH) 4}·44H2O, a Eu8 hydroxo/oxo cluster, 1, form. Countercations modulate this effect; large countercations, such as K + and Cs+, promote the formation of species 3 and 1. Addition of Al(III) as a counterion results in low pH and formation of {Eu(H2O)3(α-2-P2W17O 61)}2, 4, with Al(III) counterions bound to terminal W-O bonds. The four species observed in these speciation studies have been isolated, crystallized, and characterized by X-ray crystallography, solution multinuclear NMR spectroscopy, and other appropriate techniques. These species are 1, (NH4)22{(Eu2PW10O38) 4(W3O8(H2O)2(OH) 4}·44H2O (P1; a = 20.2000(0), b = 22.6951-(6), c = 25.3200(7) A; α = 65.6760(10), β = 88.5240(10), γ = 86.0369(10)°; V = 10550.0(5) A3; Z = 2), 2, Al(H 3O){Eu(H2O)2PW11O 34}·20H2O (P1, a = 11.4280(23), b = 11.5930(23), c = 19.754(4) A; α = 103.66(3), β = 95.29(3), γ = 102.31(3)°; V = 2456.4(9) A3; Z = 2), 3, Cs 11Eu(PW11O34)2·28H 2O (P1; a = 12.8663(14), b = 19.8235(22), c = 21.7060(23) A; α = 114.57(0), β = 91.86(0), γ = 102.91(0)°; V = 4858.3(9) A3; Z = 2), 4, Al2(H3O) 8{Eu(H2O)3(α-2-P2W 17O61)}2·29H2O (P1; a = 12.649(6), b = 16.230(8), c = 21.518(9) A; α = 11.1.223(16), β = 94.182(18), γ = 107.581(17)°; V = 3842(3) A;3; Z = 1).
Zhang, Cheng,Howell, Robertha C.,Scotland, Kymora B.,Perez, Frances G.,Todaro, Louis,Francesconi, Lynn C.
p. 7691 - 7701
(2008/10/09)

Thermal disproportionation of hypophosphorous acid
Thermal disproportionation of hypophosphorous acid was studied to find the reaction order, the rate constant and activation energy of the process, and also the temperature ranges in which the reaction rate is the highest.
Shechkov,Pevneva,Meshkova
p. 1354 - 1355
(2007/10/03)

A new method for the preparation of peroxymonophosphoric acid
A new method for the preparation of peroxymonophosphoric acid (H3PO5) has been developed. It utilizes a biphasic solution to moderate the vigorous reaction between phosphorous pentoxide (P2O5) and hydrogen peroxide (H2O2). P2O5 is suspended in carbon tetrachloride (CCl4), and concentrated H2O2 is slowly added while being vigorously stirred at low temperature. Careful control of the reaction temperature through the slow addition of H2O2 is critical. Using typical preparation conditions (P2O5:H2O2 = 0.5:1, H2O2 70 wt %, 2°C, 120-180 min), ～70% of the H2O2 is effectively converted to H3PO5. Increasing the concentration of H2O2, as well as the mole ratio of P2O5:H2O2, leads to an even higher % conversion of H2O2 to H3PO5. The addition of glacial acetic acid to the P2O5:H2O2 suspension at the end of the 120-180 min reaction (P2O5:H2O2:CH3COOH = 0.5:1:0.3) leads to the formation of peracetic acid in addition to H3PO5, and to an overall increase in the conversion ratio of total peroxy acids based on H2O2 (>95%).
Zhu, Tian,Chang, Hou-Min,Kadla, John F.
p. 156 - 160
(2007/10/03)

Kinetics and mechanism of oxidation of lower oxyacids of phosphorus by tetrabutylammonium tribromide
Oxidation of lower oxyacids of phosphorus by tetrabutylammonium tribromide (TBATB) in aqueous acetic acid leads to the formation of corresponding oxyacids with phosphorus in a higher oxidation state. The reaction exhibits 1:1 stoichiometry. The reaction is first order each in [TBATB] and [oxyacids]. The reaction does not induce polymerization of acrylonitrile. There is no effect of tetrabutylammonium chloride on the reaction rate. The proposed reactive oxidizing species is tribromide ion. It has been shown that the pentacoordinated tautomer of the phosphorus oxyacid is the reactive reductant. The oxidation of deuteriated oxyacids exhibits a substantial primary kinetic isotope effect. The effect of solvent composition indicates that the rate increases with an increase in the polarity of the solvent. A mechanism involving transfer of a hydride ion in the rate-determining step has been proposed.
Sharma, Pradeep K
p. 1612 - 1615
(2007/10/03)

Methylcyclotetradec-5-en-1-ones
Disclosed are compounds of formula I having a strong musk-like odor: In formula I, R1and R2are hydrogen or methyl, with the proviso that when R1is methyl, R2is hydrogen, and when R1is hydrogen, R2is methyl. The compounds of formula I may be in the Z- and/or in the E-form. Methods of making the compounds of formula I and compositions containing such compounds are also disclosed.
-
(2008/06/13)

Method for production of maleic anhydride
In the production of maleic anhydride by the contact of a raw material gas containing an aliphatic hydrocarbon of not less than 4 carbon atoms and molecular oxygen with a vanadium-phosphorus oxide catalyst, the raw material gas is caused to allow presence therein of nitrogen and an inert gas possessing a thermal conductivity of not less than 800 (10?4Wm?1K?1) at 700 K. The gas formed by the oxidation reaction is allowed to contact an absorbent to effect recovery of the produced maleic anhydride. Maleic anhydride is recovered from produced oxidation reaction gas separated from a remained oxidation reaction gas after recovering maleic anhydride, and the saparated inert gas is circulated to the reaction zone. The catalyst capable of producing maleic anhydride with a high yield can be obtained by activating the vanadium-phosphorus oxide catalyst with the gas composition containing an inert gas possessing a thermal conductivity of not less than 800 (10?4Wm?1K?1) at 700 K.
-
(2008/06/13)

Thermochemistry of High-Temperature Phases of Zirconium and Hafnium Pyrophosphates and Pyroarsenates
Using the adiabatic calorimetry method, the standard enthalpy of formation at T = 298.15 K (kJ/mol) was found to be -2806.0 ± 4.0 for β-ZrP2O7, -1975.0 ± 6.0 for β-ZrAs2O7, -2827.5 ± 4.0 for β-HfP2O7, and -2006.5 ± 4.0 for β-HfAs2O7. Based on these data, the enthalpies of polymorphic transitions in pyrophosphates (pyroarsenates) from the low-temperature to the high-temperature phase and the enthalpies of thermal decomposition of the compounds under consideration were derived.
Karyakin,Chernorukov,Bondareva
p. 701 - 704
(2008/10/08)

Kinetics and mechanism of ruthenium(III)chloride catalyzed oxidation of phosphorous acid by thallium(III) in acid perchlorate medium - Role of tautomeric forms of the phosphorous acid
The stoichiometry of ruthenium(III) chloride catalyzed oxidation of phosphorous acid by thallium(III) in acid perchlorate medium corresponds to the reaction represented by Eq. (i) Tl(III) + H3PO3 + H2O →/RuIII Tl(I) + H3PO4 + 2H+ (i) A mechanism suggesting complexation between the catalyst and substrate is envisaged and the rate law corresponding to this mechanism is represented by the Eq. (ii) -d[Tl(III)]÷dt = kKKh[Tl(III)[Ru(III)][H3PO3]÷ ([H+] + Kh)(1 + K[H3PO3]) (ii) where K and Kh are the formation and hydrolytic constants respectively. The HP(O) (OH)2 tautomeric form is assigned to be the reactive form of the phosphorous acid.
Bhasin,Dubey,Sharma,Sharma
p. 1036 - 1040
(2007/10/03)

Phase equilibria in the In2O3-P2O5-H2O system: The synthesis and properties of indium phosphates
Phase equilibria in thin layers of In2O3-P2O5-H2O mixtures were studied at 25°C and the molar ratio P2O5 : In2O3 = (3-10) : 1. A diagram of the crystallization fields of indium phosphates is mapped. The following phases were synthesized and identified by chemical and X-ray powder diffraction analyses, thin-layer chromatography, and IR spectroscopy: monophosphates InPO4 · 2H2O, InH3(PO4)2 · 4H2O, In3H15(PO4)8 · 5H2O, and In(H2PO4)3 (form B); diphosphates In2H7(P2O7)4 and In4(P2O7)3; triphosphate InH2P3O10 (form II); mixed-anion dihydrodiphosphate-cyclotetraphosphate In2H2(P2O7)(P4O 12); and polyphosphate In(PO3)3 (form C). The decomposition of these phosphates in air over the range of temperatures from 20 to 1000°C was studied by complex thermal analysis. X-ray studies were performed for powdered samples of InH3(PO4)2 · 4H2O (monoclinic space group P21/c, a = 7.605(7) A?, b = 7.754(6) A?, c = 8.627(8) A?, β = 104.69(7)°) and InPO4 · 2H2O (orthorhombic space group Pbca, a = 10.306(7) A?, b = 8.847(4) A?, c = 10.186(6) A?.
Selevich,Lyakhov,Lesnikovich
p. 249 - 256
(2008/10/08)

A neutron diffraction and computer modeling study of the interatomic structure of phosphoric acid
Wide angle neutron diffraction in combination with H/D substitution was used to determine the inter- and intramolecular structure of 100% phosphoric acid (H3PO4, PA). From radial distribution functions gHH(r), gHX(r), and gXX(r) (where X is either O or P) the hydrogen bonds were found to be characterized by a very short O...H distance (1.54 A). Within a molecule, the orientation of an OH group was found to be preferably in one of the three O-P-O planes. In the interpretation of the radial distribution functions, use was made of preliminary results of molecular dynamics simulations. Temperature effects on the structure of PA were only found in the hydrogen bond structure, which becomes somewhat less well defined when heating up from room temperature to 60°C. Polyphosphates could not be detected, probably due to the small degree of polymerization.
Tromp, R. Hans,Spieser, Stephane H.,Neilson, George W.
p. 2145 - 2150
(2007/10/03)

Kinetics and mechanisms of reactions of alkyl hydroperoxides with methylrhenium oxides
Aqueous methyldioxorhenium (MDO), prepared from methyltrioxorhenium (MTO) and hypophosphorous acid, abstracts an oxygen atom from tertiary alkyl hydroperoxides. This regenerates MTO and forms the tertiary alcohol with rate constants 3.71 × 104 L mol-1 s-1 (t-BuOOH) and 3.47 × 104 L mol-1 s-1 (t-AmOOH) at 25.0 °C in aqueous 1.0 M HOTf. MDO reacts with hydrogen peroxide first to form MTO, k = 3.36 × 104 L mol-1 s-1, which subsequently reacts with more hydrogen peroxide to form peroxorhenium complexes. In a separate study, the concomitant slow decomposition of alkyl hydroperoxides and MTO (to ReO4-) was investigated. The rate law is v = k[MTO][RCMe2OOH]/[H+], with k = 7.4 × 10-5 s-1 (R = Me) and k = 8.4 × 10-5 s-1 (R = Et) at 25.0 °C in aqueous solution at μ 1.0 M. 1H NMR spectroscopy and GC revealed organic products suggestive of radical reactions. The products from t-BuOOH are acetone, methanol, tert-butyl methyl ether, methane, ethane, and rerf-butyl methyl peroxide. With CH2DReO3, it could be shown that both t-BuOOH and MTO were sources of the methane. The rate of decomposition of MTO shows an inverse-first-order dependence on [H+] throughout the range pH 1-6.42.
Brittingham, Kimberly A.,Espenson, James H.
p. 744 - 750
(2008/10/08)

Meadowfoam amidopropyl dimethyl amine salts
The present invention deals with the composition of matter and the utilization of certain novel amido amine salts of meadowfoam amido propyl dimethyl amine. These materials are useful in personal care applications.
-
(2008/06/13)