Patent GB-475818-A (GB)
Title: Improvements in the manufacture and production of trimethylamine
Filed: 1936-05-27
Abstract: Trimethylamine is recovered from mixtures thereof with substantial amounts of free ammonia by treatment with an amount of solvent insufficient for complete solution, the undissolved portion comprising the trimethylamine being separated and, if desired, rectified to obtain the pure amine.  Suitable solvents include water, aqueous solutions of alkalis, alkali halides or sulphates, alkaline earth halides, ammonium salts or copper salts, or organic substances such as alanine, glycocoll, glycols, glycerine or carbohydrates, or organic solvents alone.  The gaseous mixture may be treated in a trickle tower or centrifugal washer with, e.g. 1 volume of water per 500--200 volumes of gas, or the liquefied gas may be treated with solvent to effect partial or complete solution, the pressure then being released in stages, if desired while heating, the amount of solvent being insufficient at the reduced pressure for complete solution and trimethylamine being evolved.  The liquefied mixture on treatment with the solvent may yield two liquid layers, e.g. a lower aqueous layer containing ammonia and an upper layer rich in trimethylamine.  If mixtures very rich or poor in ammonia are to be treated, they may first be rectified and the azeotropic mixture of trimethylamine and ammonia obtained subjected to the present process. Examples describe the treatment of a gas mixture with water in a centrifugal washer or in two disintegrators in series, the residual gas being liquefied and rectified; the treatment with saturated salt solution in a trickle tower, the ammonia solution obtained being re-used after boiling out the ammonia; and the extraction of the liquefied gases with caustic soda solution or anhydrous glycerine, the upper layer of crude amine being separated.ALSO:Trimethylamine is recovered from mixtures thereof with substantial amounts of free ammonia by treatment with an amount of solvent insufficient for complete solution, the undissolved portion comprising the trimethylamine being separated and, if desired, rectified to obtain the pure amine.  Suitable solvents include water, aqueous solutions of alkalis, alkali halides or sulphates, alkaline earth halides, ammonium salts or copper salts, or organic substances such as alanine, glycocoll, glycols, glycerine or carbohydrates, or organic solvents alone.  The gaseous mixture may be treated in a trickle tower or centrifugal washer with, e.g., 1 volume of water per 500--2000 volumes of gas, or the liquefied gas may be treated with solvent to effect partial or complete solution, the pressure then being released in stages, if desired while heating, the amount of solvent being insufficient at the reduced pressure for complete solution and trimethylamine being evolved.  The liquefied mixture on treatment with the solvent may yield two liquid layers, e.g. a lower aqueous layer containing ammonia and an upper layer rich in trimethylamine.  If mixtures very rich or poor in ammonia are to be treated they may first be rectified and the azeotropic mixture of trimethylamine and ammonia obtained subjected to the present process. Examples describe the treatment of a gas mixture with water in a centrifugal washer, or in two disintegrators in series, the residual gas being liquefied and rectified; the treatment with saturated salt solution in a trickle tower, the ammonia solution obtained being re-used after boiling out the ammonia; and the extraction of the liquefied gases with caustic soda solution or anhydrous glycerine, the upper layer of crude amine being separated.