The evolution of Purification
A synergic use of Distillation and Crystallization reduces operational costs and improves purity and recovery.
Organic chemicals are typically either produced via reactions or are extracted from various sources as a mixture of many components. To improve downstream functionality of the desired chemical, feedstock purification is required.
To successfully separate mixtures, the right method must be chosen -this depends on a variety of factors such as the nature of the substance, the impurities present in it and the desired degree of purity.
Most commonly, distillation and crystallization will be used with purification purposes. Distillation offers good results on many occasions, however, when the relative volatility of isomers is close it becomes impossible to separate them via distillation, plus it cannot meet required purity pDCB alone. Other considerations regarding distillation include its high energy costs and its negative impact on final product quality.
A hybrid purification solution allows you to get the best of both Distillation and Crystallization processes.
Crystallization, by far the most common method used to purify organic solids, is a single step separation process where the targeted chemical becomes unique from all others in the solution. The result is a crystal containing only the desired product, which -when separated from the remaining liquid- can reach ultra-high purities (above 99.999wt%). Nevertheless, there are downsides to the use of Crystallization alone as purification, such as its inefficiency when near eutectic.
A system that combines distillation and crystallization can be very attractive. Distillation can be used for cleaning as a pre-or post-concentration step at high throughputs. This is just one of the many specific potential applications for a hybrid solution that, on top of improving purity and recovery, can often significantly reduce operational costs.
