Specialty Resins – Caprolactum Purification
Caprolactam is used as a raw material in the manufacturing of nylon-6 polyamide. Commercial production of capro-lactam is via cyclohexanoneoximation and Beckmann rearrangement route. Since this process involves use of oleum followed by neutralization with ammonia or ammonium hydroxide, the process generates large quantities of ammonium sulfate as a waste. The capro-lactam is purified by vacuum crystallization or vacuum distillation method. But small impurities in ppm level of ammonium sulfate along with organic matter remains; and which contaminates the aqueouscapro-lactam solution and give yellow tinge to the lactam powder. It is expected to remove these inorganic salts and organic matters to the lowest of ppb level. The impurities are generated by the inefficient Beckmann’s rearrangement reaction.
Typically two streams of each SBA and SAC are recommended to remove the organic impurities, reduction in pH of the acidic lactam and reduction in the organic load of the secondary anion.
TULSION® resins when used offer the following advantages
- A tough gel and crack-free having optimal particle size distribution.
- Caprograde CPR resins can work under adverse operating conditions with good kinetics and minimum pressure drop in process
- Proven performance
- Enhanced chemical and physical stability