反应详情

温度

70 °C

20 mg analytical grade astaxanthin (97.2 mol % all-trans-astaxanthin and 1.6 mol % 9-cis-astaxanthin and 1.2 mol % 13-cis-astaxanthi) is dissolved in 1 ml pyridine and heated at 70° C. for 30 min. After addition of 8.0 ml cold water, the formed crystals are washed with water and the Raman spectrum shows the presence of crystal Form I as seen in the spectrum in FIG. 2. The X-Ray diffraction pattern is shown in FIG. 1. HPLC determination confirms the total amount of all-trans-astaxanthin and cis-astaxanthin isomers to be 100%. The astaxanthin comprises 78 mol % all-trans-astaxanthin, 3 mol % 9-cis-astaxantlhn and 19 mol % 13-cis-astaxanthin. The level of carotenoidal products is about 22 mol %. Similarly, when the pyridine solution is heated at 80° for 40 min, 28 mol % 13-cis -astaxanthin is formed and the resulting crystal is assigned as astaxanthin crystal Form I by the characteristic X-ray diffraction pattern and Raman spectrum.

1. washthe formed crystals are washed with water
2. temperatureSimilarly, when the pyridine solution is heated at 80° for 40 min