Determination of Intermediates and Side-Reaction Products in Tartrazine by Ion-Pair Liquid Chromatography

1988 ◽  
Vol 71 (5) ◽  
pp. 1003-1006
Author(s):  
Klaus Kirchmayr ◽  
Hans Malissa ◽  
Gerald P Szolgyenyi ◽  
Karl Winsauer
Keyword(s):  
Ion Pairs ◽  
Side Reaction ◽  
Solvent Mixture ◽  
Sulfanilic Acid ◽  
Ion Pair ◽  
Ethyl Esters ◽  
Reaction Products ◽  
Elution Time ◽  
Column Temperature ◽  
Water Solvent

Abstract A reverse-phase ion-pair liquid chromatographic method was applied to the measurement of uncombined intermediates and side-reaction products in Tartrazine (FD&C Yellow No. 5). These compounds, sulfanilic acid, phenylhydrazine-p-sulfonic acid, pyrazolone-T, methyl and ethyl esters of pyrazolone-T, and 4,4'-(diazoamino)-dibenzenesulfonic acid, form strong ion pairs with the tetrabutylammonium (TBA) counterion, which are separated on an RP-18 column with a methanol-water solvent mixture under acidic conditions. Baseline resolution is attained with a 0.03 mol/L TBA concentration and a pH of 2.5. With a linear step flow program and 40°C column temperature, elution time is reduced to 20 min with no equilibration between individual runs. Performance data for quantitative measurement are given in terms of calibration curve linearity (r between 0.98 and 1.00 for all compounds studied) and method detection limit (from 0.004 to 0.022% as % per weight of Tartrazine).

High Performance Liquid Chromatographic Determination of Intermediates/Side Reaction Products in FD&C Yellow No. 5

1981 ◽  
Vol 64 (3) ◽  
pp. 665-669
Author(s):  
Robert J Calvey ◽  
Allen L Goldberg ◽  
Elizabeth A Madigan
Keyword(s):  
High Performance ◽  
Side Reaction ◽  
Chromatographic Determination ◽  
Total Sample ◽  
High Performance Liquid Chromatographic ◽  
Sulfanilic Acid ◽  
Reaction Products ◽  
Anion Exchange Column ◽  
Strong Anion Exchange ◽  
Liquid Chromatographic

Abstract A rapid, sensitive, reproducible method that uses a strong anion exchange column and high performance liquid chromatography is described for determining intermediates/side reaction products in FD&C Yellow No. 5. With this method, 3 intermediates (sulfanilic acid, pyrazolone-T, and phenylhydrazinep- sulfonic acid) and 2 side reaction products (ethyl ester of pyrazolone-T and 4,4′-(diazoamino)dibenzenesulfonic acid) are eluted in a reproducible pattern by increasing the ionic strength of a buffered mobile phase. The intermediates sulfanilic acid and pyrazolone- T and the 2 side reaction products are quantitated; the intermediate phenylhydrazine-p-sulf onic acid is detected but not quantitated. Average recoveries for intermediates/side reaction products quantitatively determined in FD&C Yellow No. 5 samples were 99-104%. The amounts of intermediates/ side reaction products recovered were 0.005-0.18% by weight of the total sample.

Stereospecific 1,3-H Transfer of Indenols Proceeds via Persistent Ion-Pairs Anchored By NH···Pi Interactions

2018 ◽  
Author(s):  
David Ascough ◽  
Fernanda Duarte ◽  
Robert Paton
Keyword(s):  
Computational Analysis ◽  
Ion Pairs ◽  
Ion Pair ◽  
Hydrogen Atom Transfer ◽  
Polar Solvents ◽  
Chirality Transfer ◽  
Activation Barriers ◽  
Sense And Avoid ◽  
Phase Dynamics ◽  
Pi Interactions

The base-catalyzed rearrangement of arylindenols is a rare example of a suprafacial [1,3]-hydrogen atom transfer. The mechanism has been proposed to proceed via sequential [1,5]-sigmatropic shifts, which occur in a selective sense and avoid an achiral intermediate. A computational analysis using quantum chemistry casts serious doubt on these suggestions: these pathways have enormous activation barriers and in constrast to what is observed experimentally, they overwhelmingly favor a racemic product. Instead we propose that a suprafacial [1,3]-prototopic shift occurs in a two-step deprotonation/reprotonation sequence. This mechanism is favored by 15 kcal mol<sup>-1</sup> over that previously proposed. Most importantly, this is also consistent with stereospecificity since reprotonation occurs rapidly on the same p-face. We have used explicitly-solvated molecular dynamics studies to study the persistence and condensed-phase dynamics of the intermediate ion-pair formed in this reaction. Chirality transfer is the result of a particularly resilient contact ion-pair, held together by electrostatic attraction and a critical NH···p interaction which ensures that this species has an appreciable lifetime even in polar solvents such as DMSO and MeOH.

scholarly journals Tripodal, Squaramide-Based Ion Pair Receptor for Effective Extraction of Sulfate Salt

Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2751
Author(s):  
Damian Jagleniec ◽  
Marcin Wilczek ◽  
Jan Romański
Keyword(s):  
Ion Pairs ◽  
Binding Mode ◽  
Selective Extraction ◽  
Ion Pair ◽  
Hofmeister Series ◽  
Sulfate Salt ◽  
Lower Affinity ◽  
High Affinity ◽  
Binding Domains ◽  
Hydrated Sulfate

Combining three features—the high affinity of squaramides toward anions, cooperation in ion pair binding and preorganization of the binding domains in the tripodal platform—led to the effective receptor 2. The lack of at least one of these key elements in the structures of reference receptors 3 and 4 caused a lower affinity towards ion pairs. Receptor 2 was found to form an intramolecular network in wet chloroform, which changed into inorganic–organic associates after contact with ions and allowed salts to be extracted from an aqueous to an organic phase. The disparity in the binding mode of 2 with sulfates and with other monovalent anions led to the selective extraction of extremely hydrated sulfate anions in the presence of more lipophilic salts, thus overcoming the Hofmeister series.

Ion pair binding by an l-tyrosine-based polymerizable molecular receptor

2015 ◽  
Vol 39 (8) ◽  
pp. 6216-6222 ◽  
Author(s):  
Szymon Zdanowski ◽  
Jan Romański
Keyword(s):  
Ion Pairs ◽  
Functional Polymers ◽  
Ion Pair

A polymerizable molecular receptor able to bind ion pairs and new functional polymers containing the receptor units were synthesized and characterized.

Axle component separated ion-pair recognition by a neutral heteroditopic [2]rotaxane

2014 ◽  
Vol 50 (13) ◽  
pp. 1540-1542 ◽  
Author(s):  
Richard C. Knighton ◽  
Paul D. Beer
Keyword(s):  
Alkali Metal ◽  
Metal Cation ◽  
Alkali Metal Cation ◽  
Ion Pairs ◽  
Ion Pair ◽  
Sodium Cation ◽  
Halide Anion ◽  
Cooperative Recognition

A neutral heteroditopic pyridine N-oxide axle containing [2]rotaxane, synthesised via sodium cation templation, displays cooperative recognition of alkali metal cation-halide anion ion-pairs in an unprecedented axle component separated ion-pair binding fashion.

scholarly journals Synthesis and biotical activity of bacterial cellulose 6-(2-phthalimidoethanesulfonate)

2020 ◽  
Vol 61 (2) ◽  
pp. 29-36
Author(s):  
Zoya P. Belousova ◽  
Keyword(s):  
Bacterial Cellulose ◽  
Side Reaction ◽  
Hydroxyl Group ◽  
Hydroxyl Groups ◽  
Cellulose Derivatives ◽  
Wound Surface ◽  
Reaction Products ◽  
Absorption Bands ◽  
Hydroxymethyl Group ◽  
Antibacterial And Antifungal

Bacterial cellulose obtained by culturing Gluconacetobacter sucrofermentans in HS environment was converted to sulfonate derivatives using methane-, toluene- and 2-phthalimidoethanesulfonic acids in pyridine. When the ratio of the starting reagents is 1 : 1, the modification of bacterial cellulose according to the primary hydroxyl group of glucopyranose fragments is most likely. The formation of 6-substituted bacterial cellulose derivatives was observed in the reaction mixture. The IR spectra of the reaction products contain absorption bands, which are specific for (O–SO2) group in the region 1377-1338 cm−1 (as), 1178-1154 cm−1 (s), fragments of the corresponding sulfonic acids, as well as free hydroxyl groups of glucopyranose in the region 3495-3382 cm−1. Bacterial cellulose 2-phthalimidoethanesulfonate was dissolved in pyridine. After drying with a desiccant in a desiccator, it turned into a dense transparent film of brown color. The increased molecular film allows to explain the side reaction occurring between the oxo group and fragments of one of the chains of modified cellulose and the non-substituted hydroxymethyl group. The IR spectrum of bacterial cellulose 6-(2-phthalimidoethanesulfonate) contains absorption bands in the region 1711 cm−1, which are specific for (Ar–CO–O) group, and absorption bands in the region 1618 cm−1, which prove the presence of (CO–NH) group. In order to impart antibiotic properties to the bacterial cellulose 6-(2-phthalimido-ethanesulfonate) film, it was physically modified with clotrimazole. The obtained experimental data showed that the films subjected to treatment with a 1% solution of clotrimazole have antibacterial and antifungal effects and prevent the growth of pathogenic microbiota on the wound surface. The exit rates of clotrimazole from the bacterial cellulose 6-(2-phthalimidoethanesulfonate) film and from the pure bacterial cellulose film differed, but only slightly. 2-Phthalimidoethanesulfonate bacterial cellulose films can be used to form composites of effective wound covering, since in addition to the unique properties of bacterial cellulose itself (low allergenicity and adhesion to the wound surface, high hygroscopicity) they will have a regenerating effect.

Isotope effects and activation parameters for the proton transfer reaction from 1-(4-nitrophenyl)-1-nitroethane to free anions and ion pairs of cesium n-propoxide in n-propanol solvent

1986 ◽  
Vol 64 (6) ◽  
pp. 1021-1025 ◽  
Author(s):  
Arnold Jarczewski ◽  
Grzegorz Schroeder ◽  
Przemyslaw Pruszynski ◽  
Kenneth T. Leffek
Keyword(s):  
Proton Transfer ◽  
Rate Constants ◽  
Isotope Effects ◽  
Ion Pairs ◽  
Activation Parameters ◽  
Solvation Shell ◽  
Ion Pair ◽  
Initial State ◽  
Free Ion ◽  
Deuteron Transfer

Rate constants for the proton and deuteron transfer from 1-(4-nitrophenyl)-1-nitroethane to cesium n-propoxide in n-propanol have been measured under pseudo-first-order conditions with an excess of base for four temperatures between 5 and 35 °C. Using literature values of the fraction of cesium n-propoxide ion pairs that are dissociated into free ions, separate second-order rate constants for the proton and deuteron transfer to the ion pair and to the free ion have been calculated. The cesium n-propoxide ion pair is about 2.8 times more reactive than the free n-propoxide ion. The primary kinetic isotope effects for the two reactions are the same (kH/kD = 6.1–6.3 at 25 °C) within experimental error. The enthalpy of activation is smaller for the ion-pair reaction and the entropy of activation more negative than for the free-ion reaction. For proton transfer, ΔH±ion pair = 8.3 ± 0.2 kcal mol−1, ΔH±ion = 9.6 ± 1.0 kcal mol−1, ΔS±ion pair = −12.3 ± 0.6 cal mol−1 deg−1, ΔS±ion = −10.1 ± 3.4 cal mol−1 deg−1. The greater reactivity of the ion pair relative to the free ion is interpreted in terms of the weaker solvation shell of the ion pair in the initial state.

QUANTITATIVE ANALYSIS OF COMBUSTION PRODUCTS BY GAS CHROMATOGRAPHY: THE OXIDATION OF A RICH n-PENTANE–AIR MIXTURE IN A FLOW SYSTEM

1960 ◽  
Vol 38 (9) ◽  
pp. 1455-1466 ◽  
Author(s):  
S. Sandler ◽  
J. A. Beech
Keyword(s):  
Gas Chromatography ◽  
Flow System ◽  
Combustion Products ◽  
Reaction Products ◽  
Programming Technique ◽  
Column Temperature ◽  
Decomposition Reactions ◽  
Rich Mixture ◽  
Flight Mass Spectrometry ◽  
Simple Column

A description is given of an apparatus suitable for investigations of the oxidation and decomposition reactions of volatile hydrocarbon vapors in a flow system. Most of the reaction products are analyzed quantitatively by gas chromatography in a single-stage process involving a simple column-temperature programming technique. The products of the oxidation of a rich mixture of n-pentane and air in an annular reactor of Vycor over a wide temperature range are shown in detailed analysis. The products, as identified by several techniques including time-of-flight mass spectrometry and infrared spectrophotometry, include C2—C5 mono-olefins, two di-olefins, C1—C4 saturated aldehydes, an unsaturated aldehyde, and 2-methyl tetrahydrofuran in addition to those usually associated with the complete oxidation of n-pentane.

Octahedral cobalt(III) complexes in dipolar aprotic solvents. II. Association between cis- and trans-dichlorobisethylenediamine cobalt(III) cations,[Co en2 Cl2]+, and chloride and bromide ions in the solvents NN-dimethylformamide, dimethyl sulphoxide, and LVN-dimethylacetamide

1966 ◽  
Vol 19 (1) ◽  
pp. 43 ◽  
Author(s):  
WA Millen ◽  
DW Watts
Keyword(s):  
Spectrophotometric Method ◽  
Ion Pairs ◽  
Ion Association ◽  
Ion Pair ◽  
Association Constants ◽  
Dimethyl Sulphoxide ◽  
Aprotic Solvents ◽  
Ion Association Constants ◽  
Cis And Trans ◽  
Dipolar Aprotic Solvents

Ion association constants at 30� have been determined for the cis-[Co en, Cl2]+Cl- ion pair in NN-dimethylformamide (DMF), NN-dimethylacetamide (DMA), and at 20.0�, 25.0�, and 30.0� in dimethyl sulphoxide (DMSO), by a spectrophotometric method. Association constants for the cis-[Co en2 Cl2]+Br- and the trans- [Co en2 Cl2]+Cl- ion pairs have also been determined in DMF at 30�.

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