Diazotization Of Anilines Research Articles

An Investigation of Fastness and Potential Antibacterial Features on Cotton Fabric Colored with Novel Azo Compounds

Novel azo compounds were synthesized by diazotization of aniline and of 3-aminopyridine in the presence of NaNO2 and HCl, followed by coupling with 2-methylresorcinol in alkaline media. The structures were characterized using FT-IR, 1H NMR, and 13C NMR analysis. The main purpose of the present study is to investigate coloration applications, and antibacterial and fastness properties of the new azo structures in textile industry. Exhaust dyeing processes were applied on cotton fabric. Color strength ( K/ S values), L, a*, and b* values were measured. The color fastness values (to rubbing, light, perspiration, washing) of azo compounds on cotton fabric were presented according to ISO standards for comparison. Antibacterial activity assessment of the colored fabrics was performed according to AATCC 147-2016 test method against two types of bacteria: Staphylococcus aureus and Klebsiella pneumoniae. The fabric dyed with 2-methyl-4-[pyridin-3-yldiazenyl]benzene-1,3-diol demonstrated acceptable antibacterial activity against S. aureus.

Arenediazonium sulfonates: synthesis, comparison of structural and physicochemical properties

Aromatic diazonium salts are important building blocks in organic synthesis. The present review is concerned with such aromatic diazonium sulfonates as tosylates, dodecylbenzenesulfonates, triflates, camphorsulfonates, silica sulfates. The first part of the review provides information on the synthesis and application of these diazonium salts. It is shown that these diazonium compounds are easily synthesized by diazotization of anilines with sodium nitrite or alkyl nitrites in the presence of corresponding sulfonic acids with high yields. These diazonium salts have found wide application in the synthesis of aromatic azides, halides, triazenes, azo dyes, stilbenes, biaryls, etc. The second part of the article presents information on the comparison of the results of X-ray analysis, infrared spectroscopy and thermal analysis. The structure of diazonium sulfonate salts corresponds to the structure of classical diazonium salts (chlorides, sulfates, tetrafluoroborates). A significant difference between arenediazonium sulfonates and other diazonium salts is their explosion safety and stability in an individual form. Arenediazonium tosylates, triflates and camphorasulfonates are easily soluble both in water and in polar organic solvents. Arenediazonium dodecylbenzenesulfonates are soluble in nonpolar organic media. These features of sulfonate salts are paramount for distinguishing characteristics of the effect of the acid anion on the stability, solubility and reactivity of diazonium salts.

Synthesis, characterization and antimicrobial activity of peanut skin extract-azo-compounds

Peanut skin extract, an agro-waste and a source of flavonoids has been extracted from peanut skin and employed as a precursor for the synthesis of novel azo compounds and metal complexes. The new ligand, peanut skin extract-azo-compound, was synthesized under suitable experimental conditions by diazotization of aniline and coupling with an alkaline solution of peanut skin extract. The reaction of the ligand with metal chlorides of iron and manganese under reflux yielded novel azo metal complexes. The yields of the compounds ranged from 42% to 95%. All compounds were coloured, insoluble in water but soluble in methanol, ethanol, acetone and ethyl acetate. Morphology and composition of ligands and metal complexes were corroborated by spectroscopic techniques including Fourier transform infrared spectroscopy, scanning electron microscope-energy dispersive spectrometry and UV-visible spectroscopy. The azo complexes were found to possess potent antimicrobial activities against E. coli (gram-negative bacteria) and Staphylococcus aureus (gram-positive bacteria) and hence recommended for application as antimicrobial agent, and corrosion inhibitors in anti-corrosion paints and pigments for surface coatings.

Synthesis and Characterization of 1-Amino-2-Naphthol Hydrochloride and Dyeing Potentials of 1-(1-Phenylazo)-2-Naphthol

Emergence of diverse classes of dyes occurred due to constant effort to find specific dye or class of dyes of industrial importance for various applications. Azo dyes have been reported to possess diverse applications and properties. In the present study, 1-(1-Phenylazo)-2-naphthol azo dye was synthesized by diazotization of aniline and azo coupling with 2-naphthol. This was further reduced with stannous chloride under reflux to produce 1-amino-2-naphthol hydrochloride. The results obtained from the UV-vis and IR spectra were used to elucidate the structural characteristics of the reduced compound. The dyeing potentials of the 1-(1-Phenylazo)-2-naphthol with material fabrics showed that the compound was reasonably fast to washing, rubbing and light with application of ingrain azoic dyeing method.

Synthesis, Structure, and Synthetic Potential of Arenediazonium Trifluoromethanesulfonates as Stable and Safe Diazonium Salts

Aromatic diazonium salts are valuable building blocks for organic synthesis; however, in most cases, they are unstable, unsafe, poorly soluble, and/or expensive. In this paper, we have shown that a variety of stable and safe arenediazonium triflates ArN2+ TfO– can be obtained easily and in high yields by diazotization of anilines with tert‐butyl nitrite in the presence of trifluoromethanesulfonic acid. Arenediazonium triflates are relatively shelf‐stable in the dry state. They dissolve well in water, as well as polar and even nonpolar organic solvents. Less than 800 J/g of energy is released during the thermal decomposition of these salts, which indicates their explosion safety. Arenediazonium triflates have a high reactivity in the known reactions of diazonium chemistry, and undergo an unusual metal‐free chlorodediazonization reaction with chloroform and CCl4.

Spectrophotometric determination of triclosan based on diazotization reaction: response surface optimization using Box-Behnken design.

A spectrophotometric method based on diazotization of aniline with triclosan has been developed for the determination of triclosan in water samples. The diazotization process involves two steps: (1) reaction of aniline with sodium nitrite in an acidic medium to form diazonium ion and (2) reaction of diazonium ion with triclosan to form a yellowish-orange azo compound in an alkaline medium. The resulting yellowish-orange product has a maximum absorption at 352 nm which allows the determination of triclosan in aqueous solution in the linear concentration range of 0.1-3.0 μM with R2 = 0.998. The concentration of hydrochloric acid, sodium nitrite, and aniline was optimized for diazotization reaction to achieve good spectrophotometric determination of triclosan. The optimization of experimental conditions for spectrophotometric determination of triclosan in terms of concentration of sodium nitrite, hydrogen chloride and aniline was also carried out by using Box-Behnken design of response surface methodology and results obtained were in agreement with the experimentally optimized values. The proposed method was then successfully applied for analyses of triclosan content in water samples.

Diazotization of Anilines in Vinegar: A Very Simple and Low-cost Synthesis of Iodoarenes and Arylfurans

Diazotization of Anilines in Vinegar: A Very Simple and Low-cost Synthesis of Iodoarenes and Arylfurans

Sustainable Synthesis of Balsalazide and Sulfasalazine Based on Diazotization with Low Concentrations of Nitrogen Dioxide in Air.

Low concentrations of nitrogen dioxide, which arises as a side product from a range of industrial processes, can effectively be recycled through the diazotization of anilines. The studies reported herein now demonstrate that the removal of nitrogen dioxide from gas streams is even more effective when hydrophilic anilines are used as starting materials. The diazonium salts, which are obtained in this way in up to quantitative yields, can directly be employed in azo coupling reactions, thus opening up an attractive route to the industrially important group of azo compounds.

Denitrification Combined with Diazotization of Anilines and the Synthesis of 4′-Chlorobiphenyl-2,5-diamine and 1-Chloro-4-iodobenzene

The diazotization of anilines in aqueous solution has been found to be highly useful as a key reaction step to achieve the denitrification of low-concentrated nitrogen dioxide in air. The diazonium salt from the wet scrubber—although obtained in highly diluted aqueous solution—was shown to be directly applicable in a radical Gomberg-Bachmann aryl–aryl coupling and a Sandmeyer iodination reaction.

Selective Iododeamination of Electron-Deficient Anilines Using Task-Specific Nitrite- and Iodide-Based Ionic Liquids

A convenient and rapid method for the synthesis of aryliodides via the sequential diazotization–iodination of electron-deficient anilines using IL-ONO/[bmim]I is described. IL-ONO and [bmim]I were used as a nitrosonium source for diazotization of anilines and as a iodide ion source for subsequent iodination respectively. Electron-deficient anilines were efficiently and selectively iododeaminated in the presence of other anilines in good to excellent yields. This reaction can be regarded as a new method for the preparation of synthetically and pharmaceutically important iodoarens. Selectively iododeamination of electron-poor anilines in the presence of electron-rich anilines is one of the synthetically important advantages of this new method.

Multistep flow synthesis of 5-amino-2-aryl-2H-[1,2,3]-triazole-4-carbonitriles.

1,2,3-Triazole has become one of the most important heterocycles in contemporary medicinal chemistry. The development of the copper-catalyzed Huisgen cycloaddition has allowed the efficient synthesis of 1-substituted 1,2,3-triazoles. However, only a few methods are available for the selective preparation of 2-substituted 1,2,3-triazole isomers. In this context, we decided to develop an efficient flow synthesis for the preparation of various 2-aryl-1,2,3-triazoles. Our strategy involves a three-step synthesis under continuous-flow conditions that starts from the diazotization of anilines and subsequent reaction with malononitrile, followed by nucleophilic addition of amines, and finally employs a catalytic copper(II) cyclization. Potential safety hazards associated with the formation of reactive diazonium species have been addressed by inline quenching. The use of flow equipment allows reliable scale up processes with precise control of the reaction conditions. Synthesis of 2-substituted 1,2,3-triazoles has been achieved in good yields with excellent selectivities, thus providing a wide range of 1,2,3-triazoles.

Diazotization of anilines and diazo coupling with a coupling component mediated by a polymer‐supported sodium nitrite and a polymeric acid

AbstractPolymer‐supported reagents have become the subject of considerable and increasing interest as insoluble materials in the organic synthesis. In this study, diazonium salts are generated and are coupled with a coupling component by using a polymer supported nitrite and a polymeric acid. In this procedure, the azo chromophores are formed in a clean and efficient manner, the work–up is easy and yields are high to excellent. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Copper catalyzed Gomberg–Buchmann–Hey reaction using aryldiazonium tosylate

Copper catalyzed modification of Gomberg–Bachmann–Hey reaction to synthesize symmetrical/unsymmetrical biaryls via diazotization of anilines with p-TSA and NaNO 2 system at 50 °C, in aromatic liquids as solvents and second partners was successfully developed. Aniline and 3-nitronaniline gave biphenyl and 3-nitrobiphenyl, respectively, with moderate yields. All para-substituted anilines gave comparatively higher yields while in the other cases including ortho-substituted anilines yields were lower. Except anilines with o-NHCOCH 3 and o-CONH 2 which gave symmetrical biaryls, all others gave selectively unsymmetrical biaryls.

Synthesis of some new azo dyes derived from 4-hydroxy coumarin and spectrometric determination of their acidic dissociation constants

A series of azo coumarin dyes was synthesized by the coupling of 4-hydroxy coumarin and diazonium salts, which obtained by diazotization of aniline and aniline derivatives. The azo dyes were characterized by IR, 1HNMR and UV-Visible spectra. The acid dissociation constants, K a, of the dyes were determined using electronic spectroscopic method. Substitutions effect on this parameter was reported and discussed.

Diazotisation of aromatic amines and solvolysis of diazonium salts in ethylene glycol ethers

Aniline and unhindered alkyl-substituted anilines undergo solvolysis in dioxane and DME saturated with dry hydrogen chloride on diazotisation with isoamyl nitrite to give 2-(2-chloroethoxy)ethyl aryl ethers and 2-methoxyethyl aryl ethers respectively in 36-47% yields. 2,6-Dialkyl-substituted anilines give the corresponding chloro compounds as the major product along with the aryl ethers in lower yields. Diazotisation of aniline in ethylene glycol and monomethyl ethers of ethylene glycol and diethylene glycol gave the corresponding alcoholysis products in low yields. The solvolysis of aniline did not occur on diazotisation in diethyl ether or THF.

Spectrophotometric Determination of Aniline by Azo-Dye Formation with 2, 6-Dihydroxybenzoic Acid-Application to waters

A simple and sensitive Spectrophotometric method for the determination of aniline in aqueous medium is described. The method is based on the formation of a yellow coloured azo product from the diazotisation of aniline followed by a coupling reaction with 2,6-dihydroxybenzoic acid in the presence of sodium carbonate. Absorbance of the resulting yellow azo dye is measured at 432 nrn and is stable for 1 hour at least. Beer's law is obeyed in the concentration range of 5-80|ig of aniline in a final volume of 25ml, with a molar absorptivity of 4.2xl04l.morl.cm"!, a relative error of +1.13 to+ 4.40 % and a relative standard deviation of ±0.30 to ±0.76%, depending on the concentration level. The method is successfully employed for the determination of aniline in river and waste waters.

Polymer supported nitrite esters as diazotising reagent

Summary Glycidyl methacrylate based terpolymer resin was prepared in spherical beads form by suspension polymerization of glycidyl methacrylate (0.4mol)-methyl methylacrylate (0.5mol)-divinyl benzene (0.1mol) mixture. Acid catalysed reaction of the resin beads (110-220 µm) with excess of glycerol gives corresponding modified resin with hydroxyl functions (6.86 mmol g -1 ). Upon standing in 2 M HNO 2 solution, hydroxyl groups of the later esterified with nitrous acid (3.55 mmol g -1 ). The nitrite ester functions of the resin have been demonstrated to be efficient nitrous acid precurser in diazotisation of aromatic amines. Diazotisation of aniline in 2 M HC1 solutions at O°C takes place in less than 15 minutes. Applicability and pratical yields of the method presented have been investigated by diazo coupling reaction of s- naphthol.

Determination of pKa values of some azo dyes in acetonitrile with perchloric acid

In this study, 10 −4 M acetonitrile solutions of 15 azo dyes synthesized by coupling hydroxyl containing compounds such as phenol, 1-naphthol and 2-naphthol with diazonium salts obtained by the diazotisation of aniline and aniline derivatives were determined by potentiometric titration with perchloric acid in acetonitrile at room temperature. The turning points and the half neutralization potentials of these compounds were determined using the potentiometric titration curves obtained in order to calculate their pKa values. ©

Deaminative Fluorination of Anilines with Silicon Tetrafluoride: Utility of Silicon Tetrafluoride as a Fluorine Source

Application of silicon tetrafluoride to deaminative fluorination of anilines as a fluorine source is investigated. A diazotization of anilines proceeds with silicon tetrafluoride and t-butyl nitrite under mild condition and the following fluoro-dediazoniation affords fluoroarenes in good yields.

Effect of fast neutron irradiation on the electrical conductivity of some azo pyrazolones at different temperatures

The interaction of radiant energy with substances is an extremely important problem from the viewpoint of theory and practice. The attenuation of radiant energy during its passage through matter can be utilized for automatic and continuous measurements of the thickness of sheet material, the density, etc. [l]. Organic materials experience both temporary and permanent changes in characteristics when subjected to a radiation environment. Permanent effects of radiation on organic materials are normally associated with a chemical change in the material. Most important among these chemical reactions that occur are molecular association and crosslinkage [2, 3]. In continuation of our previous physicochemical studies on different azo compounds [4-9], it is interesting to study the effect of fast neutrons on the electrical conductivity of 3-amino-4-(3-substituted phenylazo)-5(1H)pyrazolone (H, CI, CH3) within the temperature range 293 to 443 K. The ligands were prepared by direct diazotization of aniline and its m-C1 and m-CH 3 derivatives followed by coupling with 3-amino-5-(1H)pyrazolone (Fig. 1). The electrical conductivity of the ligands was measured in the temperature range 293 to 443 K. The samples were prepared in the form of tablets at a pressure of 4toncm 2 The tablets were 12mm in diameter and 0.l to 0.3ram in thickness. The samples were held between two copper electrodes with silver paste in between, and then inserted with the holder vertical into a cylindrical electric furnace. Both ends of the furnace were closed off to reduce draughts. The potential drop across the heater was varied gradually through a Variac transformer to produce a slow rate of increase of temperature to get accurate temperature measurements. The circuit used to measure the electrical conductivity consisted of a d.c. regulated power supply (Heathkit, 0 to 400 V) and a Keithley multimeter for measuring current with a sensitivity of 10 -9 A. The temperature of the sample was measured within + 0.1 K by means ofa copper-constantan thermocouple. The conductivity a of the sample was obtained through cooling after raising the temperature using the general formula