| 摘要 |
Beta-ionone by cyclisation of pseudo-ionone.. F5-. Achieved with the aid of sulphuric acid in the presence of methyl chloride at a temperature between the b.pt. of methyl chloride and room temperature, pref. -10 degrees - +5 degrees. After reaction the reaction mixture is diluted with water and liq. methyl chloride, followed by extraction with petrol ether (40-60). The preparation is continuous. Yields are 15-20% greater than prior art and less than 1% alpha-ionone is obtained. |
