1998 Fiscal Year Final Research Report Summary
Habit Control of Aspartic Acid Crystal by Using Trace Amount of Additives
| Project/Area Number |
09650839
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
反応・分離工学
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| Research Institution | Iwate University |
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Principal Investigator |
KUBOTA Noriaki Iwate University, Faculty of Engineering, Professor, 工学部, 教授 (90003863)
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| Co-Investigator(Kenkyū-buntansha) |
YOKOTA Masaaki Iwate University, Faculty of Engineering, Research Assistant, 工学部, 助手 (60250635)
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| Project Period (FY) |
1997 – 1998
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| Keywords | Aspartic acid / Amino acid / crystal growth rate / additive / impurity / crystal habit / crystal shape / L-glutamine |
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| Research Abstract |
L-glutamine, L-glutamic acid and L-aspragine were selected as effective additives. The growth rate of an asparitic acid crystal was measured in the presence of each additive. The growth rate in the direction of c-axis of the crystal was suppressed by any of these additives. The growth suppression effect of these additives was different and it was in the order of L-glutamine, L-glutamic acid and L-asparagine. The former two showed nearly the same effect, but the effectiveness of L-asparagine was half that of the former twos. These data were analyzed by a theory previously proposed by the authors. In the theory, the propagation of the steps and crystal growth rate is considered to be suppressed by additive species adsorbed on the crystal surface on the step lines at kink sites. The difference in the effectiveness among the three additives are concluded to depend on the length between the active sites on which additive species are adsorbed. Further, the difference in the length is estimated to be caused by the difference between the chemical structures of L-asparrtic acid (crystallizing species) and an additive. Thus, the chemical structure was related to the kinetics of crystal growth.
As mentioned above, the growth rate of an aspartic acid crystal was shown to be suppressed in the direction of c-axis in the presence of any of L-glutamine, L-glutamic acid and L-asparagine. In this study, the growth rates of other crystals (potassium sulfate and potassium alum crystals) were also measured in the presence of impurities and analyzed. The additives examined were effective. The habit of these crystals can be controlled by these additives. Experiments on habit control was made on potassium alum crystals by using Bismarck Brown G as an additive. The habit was controlled successfully. Experiments on habit control are still in progress.
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