N,N-Dimethylformamide DMF CAS 68-12-2

N,N-Dimethylformamide DMF CAS 68-12-2

N,N-Dimethylformamide DMF CAS 68-12-2, important ingredient for making 5cl, stock available.

N,N-Dimethylformamide Basic Parameter

DMF Picture

Overview

Dimethylformamide is referred to as DMF. It is a compound formed by replacing the hydroxyl group of formic acid with dimethylamine, with the molecular formula HCON(CH3)2. It is a colorless, transparent, high-boiling liquid with a light amine smell. It can react violently with concentrated sulfuric acid and fuming nitric acid and even explode. It is miscible with water and most organic solvents. It is a common solvent for chemical reactions. Pure dimethylformamide has no odor, but industrial-grade or deteriorated dimethylformamide has a fishy smell because it contains dimethylamine impurities. The name comes from the fact that it is a dimethyl substitute of formamide (amide of formic acid), and both methyl groups are located on the N (nitrogen) atom. Dimethylformamide is a high-boiling polar (hydrophilic) aprotic solvent that can promote the SN2 reaction mechanism. Dimethylformamide is made from formic acid and dimethylamine. Dimethylformamide is unstable in the presence of strong bases such as sodium hydroxide or strong acids such as hydrochloric acid or sulfuric acid (especially at high temperatures), and is hydrolyzed into formic acid and dimethylamine.

Purification and water removal methods

DMF can be mixed with most organic solvents and water at will, and has good solubility for organic and inorganic compounds. N, N-dimethylformamide contains a small amount of water. It decomposes somewhat during atmospheric distillation to produce dimethylamine and carbon monoxide. In the presence of acid or alkali, the decomposition is accelerated. Therefore, after adding solid potassium hydroxide (sodium) and leaving it at room temperature for several hours, it will partially decompose. Therefore, calcium sulfate, magnesium sulfate, barium oxide, silica gel or molecular sieve are most commonly used for drying, and then reduced pressure distillation is performed to collect the fraction at 76℃/4800Pa (36mmHg). If there is more water, 1/10 volume of benzene can be added, and the water and benzene can be evaporated at normal pressure and below 80℃, and then dried with anhydrous magnesium sulfate or barium oxide, and finally reduced pressure distillation is performed. The purified N, N-dimethylformamide should be stored away from light. If there are free amines in N, N-dimethylformamide, 2, 4-dinitrofluorobenzene can be used to produce color to check.

production method

Since the first synthesis of dimethylformamide by the reaction of formic acid and dimethylamine in 1899, the process of synthesizing dimethylformamide with different raw materials has been developed, such as dimethylamine-carbon monoxide method, formamide-dimethylamine method, hydrocyanic acid-methanol method, acetonitrile-methanol method, methyl formate-dimethylamine method, trichloroacetaldehyde-dimethylamine method, etc. However, the current industrial production abroad is still dominated by the dimethylamine-carbon monoxide method. 1. Methyl formate-dimethylamine method: formic acid and methanol are esterified to form methyl formate, which is then reacted with dimethylamine in gas phase to form dimethylformamide, and then methanol and unreacted methyl formate are recovered by distillation and then vacuum distilled to obtain the finished product. 2. Dimethylamine-carbon monoxide method: dimethylamine and carbon monoxide are directly reacted under the action of sodium methoxide to obtain the finished product. The reaction conditions are 1.5-2.5MPa and 110-150℃. The crude product is distilled to obtain the finished product. 3. Methyl formate is synthesized from carbon monoxide and methanol under high pressure and 80-100°C via carbonylation, and then reacted with dimethylamine to form dimethylformamide, which is then distilled to obtain the finished product. 4. Chloroacetaldehyde method: Chloroacetaldehyde is obtained by reacting dimethylamine.

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