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Seeded batch cooling crystallization with temperature cycling for the control of size uniformity and polymorphic purity of sulfathiazole crystals
journal contribution
posted on 2009-12-16, 11:33 authored by Mohd R. Abu Bakar, Zoltan NagyZoltan Nagy, Chris RiellyChris RiellyAn experimental study has been conducted to evaluate the capability of a seeded batch cooling
crystallization with a temperature cycling method to produce a narrow crystal size distribution and grow
a desired polymorphic form of sulfathiazole crystals. The study used focused beam reflectance
measurement (FBRM), and attenuated total reflectance ultraviolet/visible (ATR-UV/Vis) spectroscopy
for the in-situ monitoring and control of the process. Based on the FBRM readings, the process was
driven using a feedback control approach that employs alternating cycles of heating and cooling phases
so that the number of counts, corresponds to the number of seed particles, is maintained, whilst the
square-weighted chord length distribution, which indicates the dynamic progress of the growth of the
seeds in the system, is increased. Results of the experiments show that the temperature cycling method promoted Ostwald ripening, which helped in accelerating the growth and enhancing the size uniformity
of the product. The method also has a good prospect to be implemented for the control of polymorphic
purity. Seeds of Form I and Form II could be grown from n-propanol and water, respectively. Form I
seeds in water were first transformed into Form II and/or swamped by nuclei of Form II, before the
growth of the newly formed crystals took place. Seeds of Form II and Form III in n-propanol however
were not able to grow at all. This study confirmed that the nucleation and growth of sulfathiazole
crystals are solvent-mediated and the insight into these phenomena was captured very well by the in-situ
monitoring tools.
History
School
- Aeronautical, Automotive, Chemical and Materials Engineering
Department
- Chemical Engineering
Citation
ABU BAKAR, M.R., NAGY, Z.K. and RIELLY, C.D., 2009. Seeded batch cooling crystallization with temperature cycling for the control of size uniformity and polymorphic purity of sulfathiazole crystals. Organic Process Research and Development, 13 (6), pp. 1343-1356.Publisher
© ACS PublicationsVersion
- NA (Not Applicable or Unknown)
Publication date
2009Notes
This article is closed access. It was published in the journal, Organic Process Research & Development [© ACS Publications]: http://pubs.acs.org/journal/oprdfkISSN
1083-6160;1520-586XLanguage
- en