| Summary: | 碩士 === 東海大學 === 化學工程學系 === 96 === In this study, benzoin was micronized via the rapid expansion of the supercritical solution (RESS) process in which a two-step approach was adopted. In the first step, the one-factor-at-a-time method was employed to study the effects of extraction temperature, extraction pressure, pre-expansion temperature, post-expansion temperature, and orifice nozzle size on benzoin particle size. The size and morphology of the particles were investigated by scanning electron microscopy (SEM), and average diameter (Davg) and ratio of average long to short diameter (L/S)avg were calculated. Based on thermo-gravimetric analysis (TGA) and X-ray diffraction (XRD), it was found that, unprocessed benzoin particles, the RESS-treated particles exhibited similar crystal structure and thermal sensitivity. No decomposition and denaturalization were found for the RESS-processed particles. In this work, micronization of benzoin particles was successfully carried out using the RESS process. The average long and short diameters of the original benzoin particles were 147.31μm and 59.16μm, respectively. On the other hand, it turned out the average long and short diameters of micronized particles were respectively reduced to the range of 0.28~1.45μm and of 0.20~0.53μm.
In the second step, three selected factors, namely extraction temperature, extraction pressure, and pre-expansion temperature, were incorporated into the Box-Behnken design and response surface method (RSM) was subsequently used to analyze the outcome of the design. Analysis of variance (ANOVA) was then conducted in order to determine whether these factor were significant and whether parameter interactions existed. A second-order nonlinear model was also presented which can be used to produce tailor-made benzoin particles in terms of long diameter, short diameter or long to short diameter ratio.
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