Separation of Diethylamine

In processes of producing alkylamines, and particularly methyl-amines, by reacting the corresponding alkyl chlorides, halides, hydroxides and so forth, with ammonia or ammonium salts such as ammonium chloride, the reaction product usually contains substantial quantities of all three of the primary, secondary and tertiary amines, even though the temperature, pressure, proportions and other reaction conditions may be controlled so as to give rise to a preponderance of one of said amines. 

These amines being of similar behavior and having only slightly different chemical and physical properties are difficult to separate, whether present as free bases or in the form of their hydrohalide salts. 

I am aware that various special methods have been proposed for separating these amines, such as fractional distillation of azeotropic mixtures under superatmospheric pressure, with or without the addition of large quantities of ammonia, and fractional crystallization of the hydrohalide salts from a solvent such as, alcohol. None of these methods is as simple or direct, nor does it produce as sharp a separation, as that which I am about to describe. 

I have found that the lower alkylamines may be separated one from the other by taking advantage of their differences in basicity. In my preferred process, the amines, preferably the alkylamines or methy-lamines, desirably in the form of their hydrohalide, or hydrochloride salts, are treated with an alkaline material in sufficient quantity and of sufficient strength to displace one or more of the amines fi om its salt. 

The dissociation constants of the amines are a measure of their basicity. For the purpose of my invention, these dissociation constants are given as follows  

---