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Solvent-free direct preparation of dichloropropanol (DCP) from glycerol and hydrochloric acid gas was carried out in a batch reactor with a variation of reaction conditions (agitation speed, reaction time, reaction temperature, and reaction pressure), amount of H 3 PW 12 O 40 catalyst, and amount of water absorbent (silica gel blue). The reaction was conducted at high agitation speed in order to avoid mass transfer limitation between glycerol and hydrochloric acid gas. In the direct preparation of DCP from glycerol and hydrochloric acid gas, DCP formation was increased with increasing reaction time, reaction temperature, and reaction pressure. Chlorination of glycerol occurred via the following consecutive reaction steps: glycerol→monochloropropanediol (MCPD)→dichloropropanol (DCP)→trichlo-ropropane (TCP). Reaction rate decreased in the order of first-step reaction>second-step reaction>third-step reaction. The presence of H 3 PW 12 O 40 catalyst and water absorbent (silica gel blue) enhanced the formation of DCP. DCP formation was increased with increasing the amount of H 3 PW 12 O 40 catalyst and water absorbent (silica gel blue). Strong Brönsted acid site of H 3 PW 12 O 40 catalyst and water removal from the reaction system favorably served in improving DCP formation.

A new reaction model for dichloropropanol (DCP) synthesis from glycerol chlorination is proposed based on the models reported by Tesser et al. (2007) and Luo et al. (2009). Two reaction steps, glycerol to glycerol-1-acetate and α-MCP to 3-chloropropandiol-1-acetate, were defined as reversible reactions and other reaction steps were defined as irreversible processes. Using the experimental data reported by Luo et al. (2009), the values predicted in this study were compared with the previous model reported by Luo et al. (2009) using both the average absolute deviation (AAD) and root mean square deviation (RMSD). The AAD and RMSD of the new model were 31% and 33% lower than that of the existing one, respectively. Overall, the proposed model for glycerol chlorination is superior to the previous model.

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Several different designs for a header type were numerically studied to achieve uniform distribution of gas phase flow in the header of a shell-and-tube heat exchanger. The different geometries included the position and shape of the inlet nozzle, number of outlet tubes, and length. In numerical calculations, the k-epsilon realizable turbulent model was employed. Standard deviation was used to evaluate the uniformity of the velocity distribution among the whole outlets of the header. As a result, flow patterns in the header could be visualized by using post-processing of numerical results. The uniformity of flow distribution increased with header length, whereas it decreased with gas flow rate. Furthermore, the optimum position and shape of the inlet nozzle could be proposed for a uniform distribution of a 1.3 m-length header, the very same used for the heat exchange of the commercially viable allyl chloride process.

Methods for regenerating H 3 PW 12 O 40 catalyst in the solvent-free direct preparation of dichloropropanol (DCP) from glycerol and hydrochloric acid gas were investigated. Regenerated H 3 PW 12 O 40 catalyst was then applied to the solvent-free direct preparation of DCP. In the solvent-free direct preparation of DCP, selectivity for DCP over H 3 PW 12 O 40 catalyst regenerated by method I (recovery of solid H 3 PW 12 O 40 catalyst by evaporating homogeneous liquidphase product solution) significantly decreased with increasing recycling run, while that over H 3 PW 12 O 40 catalyst regenerated by method II (regeneration of H 3 PW 12 O 40 catalyst by oxidative calcination of solid product recovered by method I) was slightly decreased with no significant catalyst deactivation with respect to recycling run. On the other hand, selectivity for DCP over H 3 PW 12 O 40 catalyst regenerated by method III (regeneration of H 3 PW 12 O 40 catalyst by recrystallization and subsequent oxidative calcination of solid product recovered by method II) was the same as that over fresh catalyst without any catalyst deactivation with respect to recycling run. Thus, method III was found to be the most efficient method for the regeneration of H 3 PW 12 O 40 catalyst.

-The aim of this study is to compare the total polyphenol, total flavonoid, and antioxidative activity among 5 cultivars of Korean pears cultivated in Korea. As a result of the analysis for the phenolic substance of 5 cultivars, such as Wonwhang, Sunwhang, Whangkeumbae, Chuwhang, and Shingo, the content of total polyphenol was higher in Shingo and Chuwhang, and the content of total flavonoid showed higher levels in Wonwhang and Sunwhang. In addition, this study found that DPPH radical-scavenging ability was the highest in Shingo and that the part of fruit skin showed more favorable reaction to radical ability than fruit flesh. It was also found that much better antioxidative activity was shown for the methanol solvent extraction than for the ethanol solvent extraction. The nitrite-scavenging ability showed the best for Wonwhang and Chuwhang of the cultivars and much better reaction for the methanol solvent extraction than for the ethanol solvent extraction just like the case of DPPH radical-scavenging ability. Further, nitrite-scavenging ability appeared much better reaction for the fruit skin than for the fruit flesh, and antioxidative activity dropped for the higher the range on the pH scale. From the results of this study, Korean pears are worthy of developing as a natural functional food and substance for beauty treatment through the research on bioactivity. ( Boo et al., 2012;Chung and Yoon, 2002;Heo et al., 2010 ;Kim et al., 2009;Moon et al., 2011;Park and Oh, 2003;Song et al., 2011;. 498-503(2012) Key words -