Page 293 - Chiral Separation Techniques

272 10 The Use of SMB for the Manufacture of Enantiopure Drug Substances: From …

The total column length is:
L = 1.43 m (8 columns of 18 cm length)

The velocity is then:
u = 0.0064 m s –1

The column diameter is then determined using the mean flow rate in the SMB.

∅= ⋅ 4 Q mean = 049 m
.
π ⋅u
and Equation (21) gives the shift period: ∆T = 0.92 min.

Using simulation software (essentially solving the mass balance equation in the
transitory regime), one can show that the internal profiles of the products in the sys-
tem are given by the profiles presented in Figure 10.6. Samples were taken between
columns at half periods.

C (g/L)
0,6

0,5

0,4

0,3

0,2

0,1

0
Eluent Extract Feed Raffinate

Figure 10.6. Internal profile (simulated) obtained for the separation under linear conditions.

This simulation shows that the purity of the raffinate collected over a complete
cycle is about 97.0 % and the extract is about 98.5 %. These results are close to the
target and adequate purity can be reached with minor changes in flowrates. Further
details will be given in the next section.