Sodium methoxide – CAS# 124-41-4 – Preparation and Application

General description

Sodium methoxide, CAS number [165800-06-6], or sodium methylate or sodium methanolate is the simplest sodium alkoxide. It is a colorless amorphous solid with the melting point >300 °C.^[1] It is hygroscopic, flammable and dangerously caustic base. It reacts with water to form sodium hydroxide, a corrosive material, and methanol, a flammable liquid. The heat from this reaction may be sufficient to ignite surrounding combustible material or the sodium methylate itself if the water is present in only small amounts. It is harmful if swallowed, inhaled, or absorbed through the skin. The basicity of sodium methoxide is highly dependent on the solvation and separation of the sodium cation from the methoxide anion. Base strength and rates of base-catalysed reactions may increase by several orders of magnitude in going from a polar protic solvent like methanol to a polar aprotic solvent like DMSO.^[2]

Preparation of sodium methylate

Sodium methoxide is prepared by reaction of sodium with methanol. After evaporation of methanol residual white powder is dried at 150 °C under vacuum.^[3]

Application of sodium methylate

Sodium methoxide is a widely used reagent in industry and the laboratory. It is capable of catalysing numerous reactions, including condensations, dehydrohalogenations, and other base-catalysed processes; also acts as a nucleophile in S_N2 and S_NAr reactions. Sodium methoxide is the preferred base in the Kolbe electrolytic coupling reaction in methanol.^[4] It has also found use as the preferred base for forming dichlorocarbene from ethyl trichloroacetate.^[5] As a base, sodium methoxide may also perform dehydrohalogenation reactions^[6] and catalyses the Favorskii rearrangement.^[7] It is a basic condensation catalyst typically employed in the aldol condensation reactions.^[8] Sodium methoxide has found use as a condensation catalyst in the synthesis of  various heterocycles.^[9] In industry, sodium methoxide is used as an initiator of anionic polymerization of epoxystyrene, forming a polyether with high molecular weight.^[10] It acts as a catalyst in methanolysis of vegetable oils and animal fats to give fatty acid methyl esters as a biodiesel ingredients.^[11]

Product categorization (Chemical groups):

_______________________________________________________________________