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Crystallization processes monitoring

A mechanistic model for the kinetics of gas hydrate formation was proposed by Englezos et al. (1987). The model contains one adjustable parameter for each gas hydrate forming substance. The parameters for methane and ethane were determined from experimental data in a semi-batch agitated gas-liquid vessel. During a typical experiment in such a vessel one monitors the rate of methane or ethane gas consumption, the temperature and the pressure. Gas hydrate formation is a crystallization process but the fact that it occurs from a gas-liquid system under pressure makes it difficult to measure and monitor in situ the particle size and particle size distribution as well as the concentration of the methane or ethane in the water phase. [Pg.314]

Figure A2.1 Waters ProMonix On-Line HPLC analyzer. The upper compartment door contains a keypad for programming and operation of the analyzer. The upper window allows viewing of indicator lights and a liquid crystal display that provides the operator with analyzer interface, programmed parameters, and instrument status results. The lower chamber contains the pumps, valves, injector, and detector(s) required for the chromatographic separation. The sample conditioning plate for online process monitoring is to the right of the analyzer. This is a typical process HPLC. (From Cotter, R.L. and Li, J.B., Lab Rob Autom., 1, 251,1989. With permission of VCH Publishers.)... Figure A2.1 Waters ProMonix On-Line HPLC analyzer. The upper compartment door contains a keypad for programming and operation of the analyzer. The upper window allows viewing of indicator lights and a liquid crystal display that provides the operator with analyzer interface, programmed parameters, and instrument status results. The lower chamber contains the pumps, valves, injector, and detector(s) required for the chromatographic separation. The sample conditioning plate for online process monitoring is to the right of the analyzer. This is a typical process HPLC. (From Cotter, R.L. and Li, J.B., Lab Rob Autom., 1, 251,1989. With permission of VCH Publishers.)...
G. Fevotte, New perspectives for the on-hne monitoring of pharmaceutical crystallization processes using in situ infrared spectroscopy, Int. J. Pharm., 241, 263-278 (2002). [Pg.456]

K. Pollanen, A. Hakkinen, S-P. Reinikinen, J. Rantanen, M. Kaijalainen, M. Louhi-Kultanen and L. Nystrom, IR spectroscopy together with multivariate data analysis as a process analytical tool for in-hne monitoring of crystallization process and solid-state analysis of crystalline product, J. Pharm. Biomed. Anal., 38, 275-284 (2005). [Pg.456]

Fevotte, G. Calas, J. Puel, F. Hoff, C., Applications of NIR to monitoring and analyzing the solid state during industrial crystallization processes Int. J. Pharm. 2004, 273, 159-169. [Pg.358]

On-line particle sizing by ultrasonic (acoustic attenuation) spectroscopy was developed for use during batch crystallization processes.14 Crystallization of the alpha polymorph of (l) -glutamic acid from aqueous solution was monitored by continuously pumping the crystallizing solution through an on-line ultrasonic spectrometer. The method enabled measurement of the crystal size distribution and solid concentration throughout the... [Pg.429]

Additional processes that can be monitored using spectroscopic tools of PAC are crystallization and distillation. Crystallization is an important step in manufacture of many products including APIs. Tracking the process and production of material is more valuable than testing a final product to verify that the correct crystal structure has been attained. The use of acoustic spectroscopy 4 and NIR spectroscopy48 in industrial crystallization processes has been demonstrated and will be implemented more widely. Monitoring distillation processes, such as for solvent recovery, is another growing area of use of PAC. [Pg.441]

On-line MIR ZnSe ATR analysis of microbial cultures has been used primarily for non-invasive monitoring of alcoholic or lactic fermentations. Alberti et al. [76] reported the use of a ZnSe cylindrical ATR crystal to monitor accurately substrate and product concentrations from a fed-batch fermentation of Saccharomyces cerevisiae. Picque et al. [77] also used a ZnSe ATR cell for monitoring fermentations and found that whereas NIR spectra obtained from alcoholic or lactic fermentation samples contained no peaks or zones whose absorbance varied significantly, both transmission and ATR MIR could be used successfully to measure products. Fayolle et al. [78] have employed MIR for online analysis of substrate, major metabolites and lactic acid bacteria in a fermentation process (using a germanium window flow-through cell), and... [Pg.90]

Breitschuh and Windhab (1996) described a novel use of DSC for directly investigating or monitoring crystallization processes such as those used in the fractionation of milk fat. In their technique, called DSC direct, a small sample of fat is taken from the process line, placed immediately in the sample pan of the DSC instrument, and within seconds, subjected to a heating scan. In this way, the melting characteristics of the fat at that particular stage of the process, as determined by processing conditions up to that stage, can be determined directly. [Pg.736]

Insertion of toluene molecules inside the pores, which most likely increases the distance between the complexes due to the breathing of the crystal, was monitored by confocal microscopy, and a blue shift of the emission accompanied by the visualization of the energy transfer process was detected. [Pg.69]

Figure 14. Cooling profile analysis of polarized micrographs of 100% AMF collected during the static crystallization process at the cooling rates of 0.1°C/min, 1°C/min, and 5°C/min depecting the microscopic properties (A) Df and (B) Df, monitored against changing temperature. Figure 14. Cooling profile analysis of polarized micrographs of 100% AMF collected during the static crystallization process at the cooling rates of 0.1°C/min, 1°C/min, and 5°C/min depecting the microscopic properties (A) Df and (B) Df, monitored against changing temperature.
The crystallization process of PDHS film was monitored. The spincast films of PDHS on a 6AzlG-PVA monolayer were first heated to 100°C and then cooled. The enhancement of 370 nm band with concomitant decrease of 320 nm band reflects formation of the all-fm s-zigzag Si chain conformation upon crystallization. The crystallization rate strongly depended on the initial isomerization state of the Az of the surface layer (see Figure 15.8). The crystallization process was accelerated on the Z-Az monolayer in comparison... [Pg.497]

Optical microscopy (inverted microscope) Study crystallization processes in situ Monitor transformations in suspensions Determine transformation times Screen and characterize additive/solvent interactions with specific crystal faces Identify nucleation mechanisms Measure crystal growth rates... [Pg.852]

Sensors for particle size characterization used for crystallization include ultrasound attenuation measurement/ " laser diffraction/ and laser backscatteiing/ commercially called focused beam reflectance measurement (FBRM). Ultrasonic attenuation spectroscopy has been used to monitor the crystallization process parameters such as the crystal size distribution, concentration, and the onset of nucleation during batch crystallization of L-glutamic acid/ Off-line laser diffraction has been used to measure the crystal size distribution in the development of the crystallization process for a pharmaceutical intermediate/ ... [Pg.860]


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