BATCH-OPERATED METHOD FOR PREPARING POLYAMIDES FROM AMINONITRILES Russian patent published in 2004 - IPC

FIELD: organic chemistry, chemical technology.

SUBSTANCE: invention relates to a batch-operated method for preparing polyamides from aminonitriles that elicit the improved capacity for thermal treatment. Method involves three stages. On the first stage aminonitrile or its mixture with monomers and water at temperature 90-400 C under pressure 1-350 bars to prepare the reaction mixture. On the second stage this mixture interacts at temperature from 150 to 400 C under pressure that is lower as compared with that at the first stage and temperature and pressure are taken so to obtain gaseous and liquid phases being gaseous phase is separated from liquid phase. On the third stage indicated liquid phase is mixed with gaseous or liquid water-containing phase at temperature from 150 to 370 C under pressure from 1 to 300 bars to obtain the product. The first stage is carried out in the presence Brensted's acid-base catalyst taken among the group including beta-zeolite catalyst, laminated silicate catalyst and stationary catalyst layer mainly consisting of titanium dioxide comprising 70-100 wt.-% of anatase and 0-30 wt.-% of rutile wherein up to 40 wt.-% of titanium dioxide can be replaced with tungsten oxide. The second and the third stages can be carried out in the presence this catalyst. Invention provides the complete removal of used catalyst from the reaction mixture. Method for preparing polyamides is effective and provides the improved hydrolysis of reagents, in particular, hydrolysis of acidic amide groups.

EFFECT: improved preparing method.

24 cl, 3 tbl, 9 ex