Acetamide, boiling point

Aprotic polar solvents have to be used for several reasons. They are often good solvents for both monomers (including phenolates) and amorphous polymers. In addition, they can also stabilize the Meisenheimer intermediates. Common aprotic polar solvents, such as DMSO, /V,/V-dimcthyl acetamide (DMAc), DMF, N-methyl pyrrolidone (NMP), and cyclohexylpyrrolidone (CHP) can be used. Under some circumstances, very high reaction temperature and boiling point solvents such as sulfolane and diphenyl sulfone (DPS) have to be used due to the poor reactivity of the monomers or poor solubility of the resulting, possibly semicrystalline polymers, as in the PEEK systems. 

The o-t-butyl-a-phenylbenzyl alcohol and N,N-dimethylmonochloroacetamide are dissolved in anhydrous diethyl ether. Portionwise 50% sodium hydride in the form of an oily suspension is added to the solution with stirring. After all the sodium hydride is added, the mixture is stirred at room temperature for another 3 h and then water is added to decompose excess sodium hydride. The ethereal layer is separated, dried with sodium sulfate, filtered and concentrated by removal of the solvent. The residue crystallizes upon addition of petroleum ether (boiling range 80-100°C) to which some diethyl ether is added. There is obtained 2-[o-t-butyl-a-phenylbenzyl)oxy]-N,N-dimethyl acetamide, melting point 90-91°C (81% yield). 

IR, boiling point molecular weight of acetamide in CHGla, acetone, GCI4, CH,GN, 2.5-1 6m. 

Reduction to Amines. Place 100 mg of the unknown in a reaction tube, add 0.2 g of tin, and then—in portions—2 mL of 10% hydrochloric acid. Reflux for 30 min, add 1 mL of water, then add slowly, with good cooling, sufficient 40% sodium hydroxide solution to dissolve the tin hydroxide. Extract the reaction mixture with three 1-mL portions of ether, dry the ether extract over anhydrous sodium sulfate, wash the drying agent with ether, and evaporate the ether to leave the amine. Determine the boiling point or melting point of the amine and then convert it into a benzamide or acetamide as described under 4. Primary and Secondary Amines p. 587. 

The acid-amides are, with the exception of the lowest member, formamide, H. CO. NH2 (aliquid), colourless, crystallisable compounds, the lower members being very easily soluble in water, e.g., acetamide the solubility decreases with the increase of molecular weight, until finally they become insoluble. The boiling-points of the amides are much higher than those of the adds ... 

Acetic acid, Boiling-point, n8° Proprionicadd,Boiling-point, 1410 Acetamide, 2230 Proprionamide, 2130... 

No Name Boiling point C Melting point, T Hp Density g/ml Acetamide Benzamide Benzene sulfon amide P Toluene sulfon- amide Phenyl thiourea Picrate Miscellaneous... 

No Name Melting point. C Boiling point, C Acetamide Benzamide Benzene sulfon amide P- Toluene sulfon amide Phenyl thiourea Picraie Miscellaneous... 

The most obvious route would be to find alternative solvents. However, they are difficult to find. The most likely alternatives are aprotic solvents, which are also under scrutiny, for instance of NMP (N-Methyl-2-pyrrolidone, proposed for Restriction on Annex XVII) or DMAc (dimethyl acetamide, proposed for Authorisation on Annex XrV). Other alternatives have properties that make them less suitable for instance, dimethylsulfoxide (DMSO) is solid up to 18.5 °C (it must be heated to enable processing), has a specific odor and color, and has a higher boiling point (more energy is needed to remove it). 

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