【作者】 郭军伟；

【导师】 冯亚青；

【作者基本信息】 天津大学 ， 应用化学， 2007， 硕士

【摘要】 以阿拉伯树胶为原料,通过结晶法制得粗L-阿拉伯糖,经重结晶法提纯得到纯度较高的L-阿拉伯糖。详细讨论了制备粗L-阿拉伯糖的影响因素和重结晶法提纯L-阿拉伯糖的条件。阿拉伯树胶酸解制备粗L-阿拉伯糖的最佳反应条件为阿拉伯树胶在1.5%的H2SO4为催化剂作用下,反应温度为90℃,酸解时间为4h,用氢氧化钡中和,浓缩后用甲醇溶解。经过滤浓缩结晶,得到粗L-阿拉伯糖的收率为21.0%,纯度为87.2%。重结晶法提纯L-阿拉伯糖的最佳条件为糖液质量浓度≥50%,溶液的pH=6~7,乙醇浓度≥90%,结晶时间为4h,加入晶种的量≥20%,得到的L-阿拉伯糖产率最高为15.6%(理论收率为31.0%),纯度为97.5%。所得到的结晶产物经洗涤,烘干后所得的L-阿拉伯糖外观色泽好。样品熔点为153.9~156.3℃,旋光度为(c=2.8,水)。研究了L-阿拉伯糖为原料,在钼催化剂的作用下发生异构化反应,经合成L-核糖糖胺提纯分离L-核糖的工艺。L-阿拉伯糖在催化剂作用下一步立体异构化反应转化为L-核糖的条件是5g的L-阿拉伯糖,0.5g的MoO3和0.05g的4-吡啶丙醇为复合催化剂,反应温度为100℃,反应时间为3h。合成L-核糖糖胺的条件:10.0g的碱性吸附树脂和0.50g活性炭粉末脱色和除杂,向过滤后浓缩的糖浆中加入1.0mL的甲醇回收1.59g的L-阿拉伯糖,浓缩的糖浆加入乙醇和苯胺,结晶得到L-核糖糖胺0.66g,收率为40%。L-核糖糖胺中加入37%甲醛处理后,在乙醇中得到的结晶产物经洗涤,烘干后得L-核糖0.38g,收率为13.2%,熔点为82~84℃。L-核糖的结构由红外光谱图和1H NMR图确定。更多还原

【Abstract】 Crude L-arabinose was prepared by crystallization using arabic gum as raw material and higher purity of L-arabinose was gained by recrystallization. The influencing factors were studied in detail in the preparation of crude L-arabinose and the conditions of purification of L-arabinose by recrystallization were discussed. The optimal reaction conditions for the preparation of crude L-arabinose by hydrolysis of arabic gum were 1.5% H2SO4 as catalyst, reaction temperature 90℃, hydrolysis time 4h, barium hydroxide for neutralization, methanol as solvent after concentration. After filter and concentration the solution crystallized to give crude L-arabinose with yield of 21.0% and purity of 87.2%. The optimal recrystallization conditions of exact by recrystallization were mass concentration of solution 50% above, pH value 6~7, concentration of ethanol 90% above, crystallization time 4h, mass concentration of crystal seed 20% above, and the highest yield and purity of L-arabinose was 15.6% (theoretical yield was 31.0%) and 97.5% respectively. The products washed and dried out to give L-arabinose with good appearance, melting point of 153.9~156.3℃and optical rotation of (c=2.8, water).The technology of isomerization of L-arabinose with Mo catalyst and separation of L-ribose by synthesis of L-ribose anilide was studied. L-ribose was prepared by one-step isomerization of L-arabinose with Mo catalyst. The condition of One-step Catalytic isomerization of L-ribose from L-arabinose were a solution of L-arabinose (5g), MoO3 (0.5g) and 4-pyridinepropanol (0.05g), reaction temperature 100℃, reaction time 3h. The synthetic conditions of L-ribose anilide were alkaline adsorbent resins (10.0g) and activated carbon (0.50g) used for decolorization and impurity removal, sebsequent treatment of filter and concentration gave a syrup. The syrup thus obtained was dissolved in methanol (1.0mL) and kept in a refrigerator. The resulting crystalline L-arabinose(1.59g) was filtered off and the filtrate was concentrated in vacuo. The resulting syrup was treated with anilide in ethanol and kept in a refrigerator to give L-ribose anilide (0.66g), and the yield was 40%. The L-ribose anilide was treated with formaldehyde, then crystallized from ehanol to give L-ribose (0.38g), and the yield was 13.2%, mp 82~84℃. The structure of L-ribosee was identified by IR spectrum and 1H NMR spectrum.更多还原