Continuous saponification of methyl laurate using long narrow tubes as a reactor
Continuous saponification of methyl laurate using long narrow tubes as a reactor
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DOI：
10.1021/ie0712479
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发表时间：
2008-03-05
影响因子：
4.2
通讯作者：
Ito, Seishiro
中科院分区：
文献类型：
--
作者：
Kamiouji, Atsushi;Hashimoto, Keiji;Ito, Seishiro
在硅橡胶细长管内进行了月桂酸甲酯与氢氧化钠水溶液的皂化反应。皂化速率服从能斯特扩散方程。在333K下，内径1.7 mm、长8m的管式反应器中的表观扩散常数约为烧杯中的300倍，内径为0.8 mm和1.7 mm的管式反应器的表观扩散活化能分别为14和12kJ·mol(-1)。这些值与某些试剂在12-21kJ摩尔(-1)的液相中的值符合得很好。结果表明，皂化的速率控制步骤是钠离子和/或氢氧化物离子向月桂酸甲酯的扩散。此外，表观扩散常数依赖于管式反应器的长度和内径，并且随着管式反应器内壁表面积的增大而增大。结果表明，管式反应器具有较大的内壁表面积，适用于无助剂和搅拌的皂化反应。
Saponification of methyl laurate with an aqueous solution of sodium hydroxide was carried out in long narrow tubes made of silicone rubber. The saponification rate obeyed the Nernst diffusion equation. The apparent diffusion constant in the tubular reactor with a tube of 1.7 mm inner diameter and 8 m length was about 300 times larger than that in a beaker at 333 K. The apparent activation energies of diffusion were determined to be 14 and 12 kJ mol(-1) for tubular reactors with tubes of 8 m length and 0.8 and 1.7 mm inner diameter, respectively. These values are in good agreement with those of some reagents, 12-21 kJ mol(-1), in a liquid phase. The results indicated that the rate-controlling step of the saponification is diffusion of sodium ions and/or hydroxide ions into methyl laurate. In addition, the apparent diffusion constant depended on the length and inner diameter, and it increased with an increase in surface area of the inner wall of the tubular reactor. It is concluded that a tubular reactor with a long tube and a large surface area of the inner wall is applicable to saponification without a promoter and stirring.