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Speciality Chemicals (speciality + chemical)
Selected AbstractsNonlinear model predictive control for the polymorphic transformation of L -glutamic acid crystalsAICHE JOURNAL, Issue 10 2009Martin Wijaya Hermanto Abstract Polymorphism, a phenomenon where a substance can have more than one crystal forms, has recently become a major interest to the food, speciality chemical, and pharmaceutical industries. The different physical properties for polymorphs such as solubility, morphology, and dissolution rate may jeopardize operability or product quality, resulting in significant effort in controlling crystallization processes to ensure consistent production of the desired polymorph. Here, a nonlinear model predictive control (NMPC) strategy is developed for the polymorphic transformation of L -glutamic acid from the metastable ,-form to the stable ,-form crystals. The robustness of the proposed NMPC strategy to parameter perturbations is compared with temperature control (T-control), concentration control (C-control), and quadratic matrix control with successive linearization (SL-QDMC). Simulation studies show that T-control is the least robust, whereas C-control performs very robustly but long batch times may be required. SL-QDMC performs rather poorly even when there is no plant-model mismatch due to the high process nonlinearity, rendering successive linearization inaccurate. The NMPC strategy shows good overall robustness for two different control objectives, which were both within 7% of their optimal values, while satisfying all constraints on manipulated and state variables within the specified batch time. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] Clean technology for the manufacture of speciality chemicals.JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 2 2004Cambridge, Edited by W Hoyle, ISBN 0 8504 885 , M Lancaster, The Royal Society of Chemistry, viii + 104 pp No abstract is available for this article. [source] Efficient Acylation of Anisole over Hierarchical Porous ZSM-5 StructureCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 6 2010A. Padmanabhan Abstract Friedel-Crafts acylation is one of the most important methods to prepare aromatic ketones which are used in manufacturing fine and speciality chemicals, as well as pharmaceuticals. Herein, we report an efficient and convenient procedure for the acylation of anisole with acetic anhydride, using a hierarchical porous ZSM-5 catalyst. The hierarchical porous ZSM-5 catalyst was synthesized using styrene butadiene rubber (SBR) as macroporous template. The catalysts were characterized for their structural features by using XRD, SEM, and FT-IR analyses. The effect of temperature, molar ratio, and catalyst weight on the acylation of anisole was studied in detail. The reaction parameters such as anisole-to-acetic anhydride mole ratio, catalyst weight, and reaction temperature were optimized as 5:1, 0.2 g, and 70 °C, respectively. The method described here is environmentally benign and replaces the conventional catalyst by a highly active and reusable catalyst. [source] New Scopes in Process Design using Microstructured DevicesCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 3 2005D. Kirschneck Abstract Microreaction technology offers new opportunities, especially for the production of fine and other speciality chemicals. The area of process design, however, has not been widely reported in literature. Therefore, the aim of the current paper is to give an insight into the necessary steps of industrial process design in microchemical engineering. [source] | ||||||||||