Chemical Properties
Brown to Purple Solid
Uses
3-Dimethylaminophenol can be used as neostigmine bromide intermediate and dye intermediate.
General Description
Needles (from ligroin) or a dark gray solid.
Air & Water Reactions
Sensitive to prolonged exposure to air. Insoluble in water.
Reactivity Profile
An amine and phenol. Amines are chemical bases. They neutralize acids to form salts plus water. These acid-base reactions are exothermic. The amount of heat that is evolved per mole of amine in a neutralization is largely independent of the strength of the amine as a base. Amines may be incompatible with isocyanates, halogenated organics, peroxides, phenols (acidic), epoxides, anhydrides, and acid halides. Flammable gaseous hydrogen is generated by amines in combination with strong reducing agents, such as hydrides. Phenols do not behave as organic alcohols, as one might guess from the presence of a hydroxyl (-OH) group in their structure. Instead, they react as weak organic acids. Phenols and cresols are much weaker as acids than common carboxylic acids (phenol has Ka = 1.3 x 10^[-10]). These materials are incompatible with strong reducing substances such as hydrides, nitrides, alkali metals, and sulfides. Flammable gas (H2) is often generated, and the heat of the reaction may ignite the gas. Heat is also generated by the acid-base reaction between phenols and bases. Such heating may initiate polymerization of the organic compound. Phenols are sulfonated very readily (for example, by concentrated sulfuric acid at room temperature). The reactions generate heat. Phenols are also nitrated very rapidly, even by dilute nitric acid.
Fire Hazard
Flash point data for 3-Dimethylaminophenol are not available. 3-Dimethylaminophenol is probably combustible.
Synthesis
3-Dimethylaminophenol is used to synthesize dyes and pharmaceutical intermediates. The traditional production process of this compound is to react m-aminophenol with dimethyl sulfate and then purify it in multiple steps to obtain 3-(N, N-dimethylamino)phenol. The production process requires highly toxic dimethyl sulfate, which has high requirements for safe production and raw material transportation and is not conducive to industrial production. Another method is to first react resorcinol with dimethylamine aqueous solution to obtain 3-(N, N-dimethylamino)phenol crude product, then add industrial liquid alkali to the crude product, and then add toluene to extract by-products. After neutralising the aqueous phase, wash to remove the unreacted resorcinol and then distil under reduced pressure to obtain 3-(N, N-dimethylamino)phenol. The operation is simple, the product purity is high, the raw materials are easy to store and transport, and it is easy to industrialize and produce safely.
