An one-pot method has been developed for the synthesis of azo dyes via sequential diazotization–diazo coupling of aromatic amines with coupling agents at room temperature in the presence of Bi(NO3)3. 5H2O. Short reaction times, high yields, a clean process, simple methodology, easy work-up and green ‎conditions are advantages of this protocol.‎

A rapid, simple, sensitive and selective spectrophotometric determination of nitrite using new diazotizing and coupling reagents is described. The method is based on a diazotization-coupling reaction between dapsone and iminodibenzyl in a hydrochloric acid medium. The molar absorptivity and Sandell's sensitivity were found to be 7.5 x 10(4) l mol(-1) cm(-1) and 0.000613 microg ml(-1), respectiv...

An accurate, dependable determination of 0-60 ,ug-at./l. of NOs -N in sea water has been developed. The sample is treated with tetrasodium ethylenediaminetetraacetate solution and passed through a column of copperized cadmium filings. A nearly quantitative reduction of nitrate to nitrite results. Nitrite is then determined by a diazotization method. Neither sulphide nor high nitrite concentrati...

An efficient and straightforward method for one-pot synthesis of aryl azides from the corresponding amines, employing tributylstannyl azide as transfer reagent of N3 group is described. In this procedure diazotization of aryl amines occurs under mild conditions using tert-butyl nitrite (t-BuONO) and p-toluenesulfonic acid (TsOH). A variety of substituted aryl amines, with both electron-withdraw...

The m-aminophenylarsonic acid (m-APAA) was immobilized onto the silica gel surface with covalently grafted quaternary ammonium groups via ion exchange. The diazotization of ion-bonded m-APAA resulted in a new solid-phase spectrophotometric reagent for detection of 1-naphtol in environmental water samples. The procedure of solid-phase spectrophotometric analysis is characterized by 20 μg L(-1) l...

Nanosilica periodic acid (nano-SPIA) is found to be a new, powerful, and reusable heterogeneous catalyst for the rapid synthesis of 2-naphtholazo dyes via diazotization of aromatic amines and followsazo coupling with 2-naphthol under solvent-free conditions at room temperature by grinding. Eco-friendly, heterogeneous reaction conditions, high stability of diazonium salt, simple experimental pro...

A simple and sensitive spectrophotometric determination method for the determination of nitrazepam in bulk, in pharmaceutical dosage forms and in biological fluids was developed. The method is based upon reduction of nitro group of nitrazepam by zinc and hydrochloric acid followed by diazotization and coupling with orcinol in basic medium to form a stable chromophore which absorbs at 470 nm. Th...

The design and performance of a portable, automated flow injection (FI)-based photometric monitor are described. The system is controlled by an in-house microcomputer system that enables the monitor (including a solid state detector) to operate from a 12 V battery supply. The monitor uses the cadmium reduction/diazotization method to analyse for nitrate with a linear range of 0 to 12 mg l(-1) a...