Design acrylonitrile separation

Table 11.8 Unit design and performance of the acrylonitrile separation section.

An important property for process design is the limited reciprocal solubility of acrylonitrile in water. Table 11.3 shows the dependence against temperature. The solubility of AN in water is around 7% w/w, while water in AN about 3% at 20 °C. Therefore, liquid-liquid separation by decantation can be combined advantageously with azeotropic distillation for acrylonitrile purification. 

When a mixture of styrene and acrylonitrile is polymerized in the presence of a polybutadiene latex by an emulsion radical process, an acrylonitrile-butadiene-styrene (ABS) copolymer is obtained. This ABS copolymer is actually a mixture of (a) a graft copolymer which contains some of the styrene/acrylonitrile (ST/AN) copolymer chemically bound to the polybutadiene backbone, and (b) a random copolymer, conventionally designated as a linear copolymer, which is not bound to the polybutadiene backbone but which consists of the portion of the styrene/acrylonitrile monomer that has polymerized separately. 

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