Search results
Results From The WOW.Com Content Network
In organic chemistry, an azo coupling is an reaction between a diazonium compound (R−N≡N +) and another aromatic compound that produces an azo compound (R−N=N−R’).In this electrophilic aromatic substitution reaction, the aryldiazonium cation is the electrophile, and the activated carbon (usually from an arene, which is called coupling agent), serves as a nucleophile.
N-(1-Naphthyl)ethylenediamine dihydrochloride is widely used in the quantitative analysis of nitrate and nitrite in water samples by colorimetry.It readily undergoes a diazonium coupling reaction in the presence of nitrite to give a strongly colored azo compound.
A nitrite test is a standard component of a urinary test strip. A positive test for nitrites in the urine is called nitrituria. This test is commonly used in diagnosing urinary tract infections (UTIs). A positive nitrite test indicates that the cause of the UTI is a Gram-negative organism, most commonly Escherichia coli. The reason for nitrites ...
Azo compounds are organic compounds bearing the functional group diazenyl (R−N=N−R′, in which R and R′ can be either aryl or alkyl groups).. IUPAC defines azo compounds as: "Derivatives of diazene (diimide), HN=NH, wherein both hydrogens are substituted by hydrocarbyl groups, e.g. PhN=NPh azobenzene or diphenyldiazene.", where Ph stands for phenyl group. [1]
The stained teeth of a regular betel chewer in Burma. Extrinsic discolorations are common and have many different causes. [10] The same range of factors are capable of staining the surface of restorations (e.g., composite fillings, porcelain crowns). [10] Some extrinsic discolorations that are allowed to remain for a long time may become ...
Phenazopyridine is an azo dye. [17] [18] Other azo dyes, which were previously used in textiles, printing, and plastic manufacturing, have been implicated as carcinogens that can cause bladder cancer. [19] While phenazopyridine has never been shown to cause cancer in humans, evidence from animal models suggests that it is potentially ...
Enamel microabrasion is a procedure in cosmetic dentistry used to improve the appearance of the teeth. Like tooth whitening it is used to remove discolorations of the tooth surface but microabrasion is both a mechanical and chemical procedure.
Among the various oxidants used are mercuric oxide, nitric acid, isoamyl nitrite, N-bromo succinimide, potassium permanganate, lead tetra-acetate and t-butyl hypochlorite. [8] Depending on the conditions, tetrazolium salts can be reduced to form tetrazolyl radicals or formazan: