Homogeneous catalysis of manganese(II) in acid bromate oxidation of olefinic acids

1988 ◽  
Vol 53 (12) ◽  
pp. 3138-3148 ◽  
Author(s):  
Ch. Sanjeeva Reddy
Keyword(s):  
Homogeneous Catalysis ◽  
Catalytic Effect ◽  
Catalyst Concentration ◽  
Cinnamic Acids ◽  
Olefinic Bond ◽  
First Order ◽  
Upper Limit ◽  
Π Complex ◽  
Bromide Ion ◽  
First Time

Manganese(II)-catalysed acid bromate oxidation of acrylic trans-crotonic and trans-cinnamic acids, in the presence of mercury(II), a bromide ion scavenger, exhibits first order in concentration of bromate, and reaches an upper limit with increase in substrate as well as catalyst concentration. Oxidation rate increases with acidity and is not altered when deuterium replaces either α or β proton of the olefinic acid. The catalytic effect of Mn(II) is displayed by its complex forming ability and the proposed mechanism assumes the oxidation of the formed Mn(II)-substrate π complex to Mn(III)-substrate π complex by acid bromate which further converts to products. The formation of a π complex between Mn(II) and the olefinic bond of the substrate is assumed for the first time.

The effect of polymeric and model imidazolium halides on the rate of hydrolysis of 4-acetoxy-3-nitrobenzoic acid

1985 ◽  
Vol 50 (4) ◽  
pp. 845-853 ◽  
Author(s):  
Miloslav Šorm ◽  
Miloslav Procházka ◽  
Jaroslav Kálal
Keyword(s):  
Catalyst Concentration ◽  
Low Molecular Weight ◽  
Imidazolium Chloride ◽  
First Order ◽  
Nitrobenzoic Acid ◽  
Rate Of Hydrolysis ◽  
Acid Catalyzed ◽  
Hydrolysis Of ◽  
Ethanol In Water ◽  
Direct Attack

The course of hydrolysis of an ester, 4-acetoxy-3-nitrobenzoic acid catalyzed with poly(1-methyl-3-allylimidazolium bromide) (IIa), poly[l-methyl-3-(2-propinyl)imidazolium chloride] (IIb) and poly[l-methyl-3-(2-methacryloyloxyethyl)imidazolium bromide] (IIc) in a 28.5% aqueous ethanol was investigated as a function of pH and compared with low-molecular weight models, viz., l-methyl-3-alkylimidazolium bromides (the alkyl group being methyl, propyl, and hexyl, resp). Polymers IIb, IIc possessed a higher activity at pH above 9, while the models were more active at a lower pH with a maximum at pH 7.67. The catalytic activity at the higher pH is attributed to an attack by the OH- group, while at the lower pH it is assigned to a direct attack of water on the substrate. The rate of hydrolysis of 4-acetoxy-3-nitrobenzoic acid is proportional to the catalyst concentration [IIc] and proceeds as a first-order reaction. The hydrolysis depends on the composition of the solvent and was highest at 28.5% (vol.) of ethanol in water. The hydrolysis of a neutral ester, 4-nitrophenyl acetate, was not accelerated by IIc.

scholarly journals Non-Linear First-Order Differential Boundary Problems with Multipoint and Integral Conditions

2021 ◽  
Vol 5 (1) ◽  
pp. 15
Author(s):  
Misir J. Mardanov ◽  
Yagub A. Sharifov ◽  
Yusif S. Gasimov ◽  
Carlo Cattani
Keyword(s):  
Integral Equation ◽  
Integral Boundary Conditions ◽  
Contraction Mapping Principle ◽  
Boundary Problems ◽  
Integral Boundary ◽  
Multipoint Problem ◽  
First Order ◽  
Banach Contraction ◽  
First Time ◽  
Banach Contraction Mapping Principle

This paper considers boundary value problem (BVP) for nonlinear first-order differential problems with multipoint and integral boundary conditions. A suitable Green function was constructed for the first time in order to reduce this problem into a corresponding integral equation. So that by using the Banach contraction mapping principle (BCMP) and Schaefer’s fixed point theorem (SFPT) on the integral equation, we can show that the solution of the multipoint problem exists and it is unique.

The kinetics of the decarboxylation of β-resorcylic acid in catechol

1976 ◽  
Vol 29 (2) ◽  
pp. 443 ◽  
Author(s):  
MA Haleem ◽  
MA Hakeem
Keyword(s):  
Rate Equation ◽  
Kinetic Data ◽  
Reaction Rate ◽  
Complex Mechanism ◽  
First Order ◽  
Absolute Reaction Rate ◽  
First Time ◽  
Kinetics Of ◽  
Absolute Reaction ◽  
Reaction Rate Equation

Kinetic data are reported for the decarboxylation of β-resorcylic acid in resorcinol and catechol for the first time. The reaction is first order. The observation supports the view that the decomposition proceeds through an intermediate complex mechanism. The parameters of the absolute reaction rate equation are calculated.

scholarly journals Quantum Gravity at the Corner

Universe ◽  
2018 ◽  
Vol 4 (10) ◽  
pp. 107 ◽  
Author(s):  
Laurent Freidel ◽  
Alejandro Perez
Keyword(s):  
Quantum Gravity ◽  
Symplectic Form ◽  
Direct Application ◽  
Quantum Geometry ◽  
Quantum Level ◽  
Gravitational System ◽  
Gauge Transformations ◽  
First Order ◽  
Conformal Field ◽  
First Time

We investigate the quantum geometry of a 2d surface S bounding the Cauchy slices of a 4d gravitational system. We investigate in detail for the first time the boundary symplectic current that naturally arises in the first-order formulation of general relativity in terms of the Ashtekar–Barbero connection. This current is proportional to the simplest quadratic form constructed out of the pull back to S of the triad field. We show that the would-be-gauge degrees of freedo arising from S U ( 2 ) gauge transformations plus diffeomorphisms tangent to the boundary are entirely described by the boundary 2-dimensional symplectic form, and give rise to a representation at each point of S of S L ( 2 , R ) × S U ( 2 ) . Independently of the connection with gravity, this system is very simple and rich at the quantum level, with possible connections with conformal field theory in 2d. A direct application of the quantum theory is modelling of the black horizons in quantum gravity.

scholarly journals Measurements of hydrogen cyanide (HCN) and acetylene (C<sub>2</sub>H<sub>2</sub>) from the Infrared Atmospheric Sounding Interferometer (IASI)

2013 ◽  
Vol 6 (4) ◽  
pp. 917-925 ◽  
Author(s):  
V. Duflot ◽  
D. Hurtmans ◽  
L. Clarisse ◽  
Y. R'honi ◽  
C. Vigouroux ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Hydrogen Cyanide ◽  
Atmospheric Transport ◽  
Trace Gases ◽  
First Order ◽  
Line Mixing ◽  
Atmospheric Sounding ◽  
First Time ◽  
Order Comparison ◽  
Emission Ratios

Abstract. Hydrogen cyanide (HCN) and acetylene (C2H2) are ubiquitous atmospheric trace gases with medium lifetime, which are frequently used as indicators of combustion sources and as tracers for atmospheric transport and chemistry. Because of their weak infrared absorption, overlapped by the CO2 Q branch near 720 cm−1, nadir sounders have up to now failed to measure these gases routinely. Taking into account CO2 line mixing, we provide for the first time extensive measurements of HCN and C2H2 total columns at Reunion Island (21° S, 55° E) and Jungfraujoch (46° N, 8° E) in 2009–2010 using observations from the Infrared Atmospheric Sounding Interferometer (IASI). A first order comparison with local ground-based Fourier transform infraRed (FTIR) measurements has been carried out allowing tests of seasonal consistency which is reasonably captured, except for HCN at Jungfraujoch. The IASI data shows a greater tendency to high C2H2 values. We also examine a nonspecific biomass burning plume over austral Africa and show that the emission ratios with respect to CO agree with previously reported values.

scholarly journals KINETICS OF PALM OIL TRANSESTERIFICATION IN METHANOL WITH POTASSIUM HYDROXIDE AS A CATALYST

2010 ◽  
Vol 8 (2) ◽  
pp. 219-225
Author(s):  
Yoeswono Yoeswono ◽  
Triyono Triyono ◽  
Iqmal Tahir
Keyword(s):  
Activation Energy ◽  
Palm Oil ◽  
Rate Constants ◽  
Potassium Hydroxide ◽  
Catalyst Concentration ◽  
Time Interval ◽  
Pseudo First Order Reaction ◽  
Exponential Factor ◽  
Potassium Methoxide ◽  
First Order

A study on palm oil transesterification to evaluate the effect of some parameters in the reaction on the reaction kinetics has been carried out. Transesterification was started by preparing potassium methoxide from potassium hydroxide and methanol and then mixed it with the palm oil. An aliquot was taken at certain time interval during transesterification and poured into test tube filled with distilled water to stop the reaction immediately. The oil phase that separated from the glycerol phase by centrifugation was analyzed by 1H-NMR spectrometer to determine the percentage of methyl ester conversion. Temperature and catalyst concentration were varied in order to determine the reaction rate constants, activation energies, pre-exponential factors, and effective collisions. The results showed that palm oil transesterification in methanol with 0.5 and 1 % w/w KOH/palm oil catalyst concentration appeared to follow pseudo-first order reaction. The rate constants increase with temperature. After 13 min of reaction, More methyl esters were formed using KOH 1 % than using 0.5 % w/w KOH/palm oil catalyst concentration. The activation energy (Ea) and pre-exponential factor (A) for reaction using 1 % w/w KOH was lower than those using 0.5 % w/w KOH.   Keywords: palm oil, transesterification, catalyst, first order kinetics, activation energy, pre-exponential factor

scholarly journals Phenolic profiles of the endemic species Astragalus palibinii Polozhij

2021 ◽  
Vol 38 ◽  
pp. 00063
Author(s):  
Olga Kotsupiy ◽  
Tatyana Shemetova
Keyword(s):  
Phenolic Compounds ◽  
Endemic Species ◽  
Rare Species ◽  
Hydroxycinnamic Acid ◽  
Plant Leaves ◽  
Cinnamic Acids ◽  
Phenolic Profiles ◽  
Hydroxybenzoic Acids ◽  
Ethanol Extracts ◽  
First Time

For the first time, the composition and content of phenolic compounds (PC) of plant leaves of an endemic rare species of the Xiphidium Bunge section of the genus Astragalus L. of Siberia – Astragalus palibinii Polozhij was studied by HPLC. 11 compounds of phenolic nature were identified in water-ethanol extracts of A. palibinii leaves: gallic, p-hydroxybenzoic, chlorogenic, caffeic, ferulic, trans-ferulic, cinnamic acids, isoquercitrin, rutin, isoramnetin-3-O-rutinoside and L-epicatechin. The composition of PC in the leaves of plants of three cenopopulations A. palibinii from Khakassia is the same, with the exception of one hydroxycinnamic acid in trace amounts. The content (mg per 100 g DW) of flavonol glycosides in the leaves of A. palibinii plants varies in the range of 0.442–0.907, the content of hydroxycinnamic and hydroxybenzoic acids in the range of 98.5–109.7 and 32.5–83.9, respectively. The quantitative profiles of all the studied groups of PC are characterized by significant variability in the content of individual components. The variability of the content of hydroxycinnamic acids, flavonoids and hydroxybenzoic acids was determined as very low, medium and increased, respectively.

scholarly journals Dynamic Range Analysis of the Phase Generated Carrier Demodulation Technique

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
M. J. Plotnikov ◽  
A. V. Kulikov ◽  
V. E. Strigalev ◽  
I. K. Meshkovsky
Keyword(s):  
Theoretical Analysis ◽  
Dynamic Range ◽  
Range Analysis ◽  
Upper Limit ◽  
Low Pass ◽  
Nonlinear Character ◽  
Simulation Results ◽  
Low Pass Filters ◽  
First Time ◽  
Phase Generated Carrier

The dependence of the dynamic range of the phase generated carrier (PGC) technique on low-pass filters passbands is investigated using a simulation model. A nonlinear character of this dependence, which could lead to dynamic range limitations or measurement uncertainty, is presented for the first time. A detailed theoretical analysis is provided to verify the simulation results and these results are consistent with performed calculations. The method for the calculation of low-pass filters passbands according to the required dynamic range upper limit is proposed.

scholarly journals Generation of over 1000 Diffraction Spots from 2D Graded Photonic Super-Crystals

Photonics ◽  
2020 ◽  
Vol 7 (2) ◽  
pp. 27
Author(s):  
Safaa Hassan ◽  
Yan Jiang ◽  
Khadijah Alnasser ◽  
Noah Hurley ◽  
Hualiang Zhang ◽  
...  
Keyword(s):  
Diffraction Pattern ◽  
Cell Size ◽  
Lattice Constant ◽  
Field Intensity ◽  
Lattice Model ◽  
Dual Lattice ◽  
First Order ◽  
Super Cell ◽  
First Time ◽  
Fractional Orders

For the first time, we are able to generate over 1000 diffraction spots from a graded photonic super-crystal with a unit super-cell size of 12a × 12a where a is the lattice constant and hole radii are gradually changed in dual directions. The diffraction pattern from the graded photonic super-crystal reveals unique diffraction properties. The first order diffractions of (±1,0) or (0,±1) disappear. Fractional diffraction orders are observed in the diffraction pattern inside a square with vertices of (1,1), (1,−1), (−1,−1) and (−1,−1). The fractional diffraction can be understood from lattices with a period of a. However, a dual-lattice model is considered in order to explain higher-order diffractions. E-field intensity simulations show a coupling and re-distribution among fractional orders of Bloch waves. There are a total of 12 × 12 spots in E-field intensity in the unit supercell corresponding to 12 × 12 fractional diffraction orders in the diffraction pattern and 12 × 12 fractional orders of momentum in the first Brillouin zone in k-space.

scholarly journals The Formation of Glycerol Oligomers with Two New Types of End Groups in the Presence of a Homogeneous Alkaline Catalyst

Polymers ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 144 ◽  
Author(s):  
Dawid Kansy ◽  
Kornelia Bosowska ◽  
Krystyna Czaja ◽  
Anna Poliwoda
Keyword(s):  
Catalyst Concentration ◽  
Reaction Medium ◽  
Hydroxyl Groups ◽  
Ionization Mass ◽  
Carboxylate Group ◽  
Reaction Products ◽  
Direct Infusion ◽  
Alkaline Catalyst ◽  
End Groups ◽  
First Time

The purpose of this work was to synthesize and characterize oligoglycerols with the chains of more than four repeating units. Those oligoglycerols may have some interesting applications, among others, as polyoxyalkylation starters. The glycerol oligomerization process was carried out during 12 h, at 230 °C, under the pressure of 0.4 bar, with the use of sodium carbonate as a homogeneous basic catalyst; various concentrations of the catalyst in the reaction medium were used. The reaction products were analyzed with the use of direct infusion electrospray ionization mass spectrometry (ESI-MS), nuclear magnetic resonance (13C NMR) and Fourier transform infrared spectroscopy (FTIR) techniques. Based on the analytical findings, the compositions of the obtained product mixtures and the structures of oligoglycerols present in individual fractions were determined. The effect of catalyst concentration on the composition of the post-reaction mixture was observed. Moreover, in addition to the conventional linear oligomers (α,α-oligoglycerols), two new types of the oligomers were for the first time detected in the post-reaction mixture: one with two hydroxyl groups and the other with a carboxylate group at the α-carbon atom.

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