Метил Оранжевый

Химические свойства

Orange-yellow powder. Soluble in hotwater; insoluble in alcohol.

Использование

Methyl orange is a pH indicator frequently used in titrations, also used for histological microscopy.

Подготовка

4-Aminobenzenesulfonic acid diazo, and N,N-dimethylaniline coupling.

Определение

An acid–base indicator that is red in solutions below a pH of 3 and yellow above a pH of 4.4. As the transition range is clearly on the acid side, methyl orange is suitable for the titration of an acid with a moderately weak base, such as sodium carbonate.

Общее описание

Orange powder.

Реакции воздуха и воды

Azo dyes can be explosive when suspended in air at specific concentrations. Insoluble in water.

Профиль реактивности

Methyl Orange is an azo compound. Azo, diazo, azido compounds can detonate. This applies in particular to organic azides that have been sensitized by the addition of metal salts or strong acids. Toxic gases are formed by mixing materials of this class with acids, aldehydes, amides, carbamates, cyanides, inorganic fluorides, halogenated organics, isocyanates, ketones, metals, nitrides, peroxides, phenols, epoxides, acyl halides, and strong oxidizing or reducing agents. Flammable gases are formed by mixing materials in this group with alkali metals. Explosive combination can occur with strong oxidizing agents, metal salts, peroxides, and sulfides.

Методы очистки

Recrystallise it twice from hot water, then wash it with a little EtOH followed by diethyl ether. It is an indicator: pH 3.1 (red) and pH 4.4 (yellow). [Beilstein 16 IV 510.]