Purifying gases contg. alkyl-amides e.g. dimethyl formamide - by absorption in water using counter current appts.

摘要

Alkylamides are sepd. from gases by absorption in water. A vertical counter-current appts. sub-divided into section is used. Absorbent is circulated in contact steps. 80-95 wt. % of fresh absorbent entering appts. is removed from an opt. contact step of appts, with exception of last step, in guide motion of absorbent. In all contact steps, below contact step from which absorbent is taken out of process, absorbent is circulated 4-19 times in a closed cycle. Used for purifying ventilation gases contg. dimethyl formamide, e.g obtd. in prdn of polyacrylonitrile fibres and artificial leathers. Purified gas contains 1-10 mg/m3 alkylamie. Alkylamide concn. is absorbent at appts. outlet is 1-5%. Alkylamine can be easily recovered by rectifying. Absorbent expelled in 80-95 wt. % quantity contains insignificant amts of alkylamide and can be used for washing polyacrylonitrile fibres or for biological purificn.