【作者】 刘晓娣；

【导师】 刘士荣；

【作者基本信息】 江南大学 ， 应用化学， 2007， 硕士

【摘要】 本文对活性炭负载的磷钨酸(TPA)催化剂催化合成烷基多苷(APG)进行了研究。研究包括两部分,第一部分是活性炭负载TPA催化剂的制备、吸附和脱附研究以及负载催化剂的表征。第二部分主要是APG合成工艺的优化以及APG的性能测试。分别采用浸渍法和吸附法制备了几种活性炭负载的TPA催化剂。影响活性炭在水溶液中对TPA的吸附量的因素主要是吸附时间和载体种类,影响负载催化剂TPA脱附量的主要因素有脱附时间、制备方法、负载量及载体性质。用IR、XRD、SEM等对活性炭负载TPA催化剂的表征表明,负载催化剂表面同时存在L-酸位和B-酸位,浸渍法制备的催化剂,总酸量随负载量的增大而增大;吸附法制备的催化剂,总酸量随负载量的增大而减少。TPA负载到活性炭后保持了原有的Keggin结构,负载量由小到大变化时,TPA在载体上的吸附形态也发生变化。负载量在0~8%和8~14%之间时,TPA分别以单分子吸附和多分子吸附的形式存在,当负载量超过14%时,吸附达饱和,载体表面出现体相TPA堆积。采用二步法合成了烷基多苷。第一步反应(丁苷化反应)的最优工艺条件为:最佳载体C1,负载量20%,催化剂用量为葡萄糖质量的5%,丁醇与葡萄糖摩尔比5:1,油浴温度120℃,反应时间2 h;第二步反应(苷交换反应)的最优工艺条件为:反应温度120℃,十二醇与葡萄糖摩尔比2.5:1,反应时间1 h。在最优工艺下,葡萄糖转化率为97.0%,合成得到的十二烷基多苷产品的DP值为1.35,十二烷基多苷含量达70.2%。将该催化剂在最优工艺条件下重复使用8次后,转化率仍在79%以上。APG在水溶液中的临界胶束浓度为65.5 mg/L,此时的表面张力为25.2 mN/m,泡沫力为160 mm,五分钟后的泡沫高度为158 mm。更多还原

【Abstract】 The synthesis of alkyl polyglucosides(APG) using tungstophosphoric acid(TPA)catalysts supported on activated carbon were studied. This research consists of two sections, one of which is the preparation, the adsorption and desorption characteristics and the characterization of the carbon supported TPA catalysts. The other is the optimization of APG’s synthesis technics and the testing of APG’s performances.TPA catalysts supported on several kinds of activated carbon were prepared by impregnation technique and adsorption technique. During the adsorption progress, the main factors influencing the adsorption quantity of TPA onto activated carbon are adsorption time and the characteristic of the support. During the desorption progress, the main factors influencing the desorption quantity of TPA from activated carbon are desorption time, preparation method, TPA loading amount and the the characteristic of the support. The supported catalysts were characterized by IR, XRD and SEM. There are both L-acid points and B-acid points existing on the surface of supported catalysts. With the increase of TPA loading amounts the total acid increases for catalysts prepared by impregnation technique but decreases for catalysts prepared by adsorption technique. The Keggin structure of TPA remains unaltered after being supported on activated carbon. The adsorption form altered when TPA loading amounts get changing. The adsorption process can be devided into three phases which are monomolecular adsorption(TPA loading is between 0~8%), multimolecular adsorption(TPA loading is between 8~14%) and surface packing of bulk TPA(TPA loading is above 14%).APG was synthesized using a two-step process. The optimal technics of the first step(butylglycosidation)are as follows: the best support is C1, the optimal TPA loading is 20%, the optimal catalysts use level is 5%, the best mol proportion of butyl alcohol and glucose is 5:1, the best temperature of the oil base is 120℃and the optimal reaction time is 2 h. The optimal technics of the second step(exchangement of glycosides)are as follows: the best reaction temperature is 120℃, the best mol proportion of dodecyl alcohol and glucose is 2.5:1 and the optimal reaction time is 1 h. Under the optimal technics, the glucose conversion is 97.0%, the DP value of APG product is 1.35. The content of APG12 is 70.2%. The glucose conversion remained relatively high(79%) after being 8 times reclaimed and reused. The APG product has a cmc value of 65.5 mg/L and the corresponding surface tension is 25.2 mN/m. The foam height of APG is 160 mm, and 158 mm after 5 min.更多还原