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丙酸异戊酯是无色液体，具有菠萝及洋梨香气,微溶于水，可混溶于乙醇、乙醚，不溶于甘油 。可用作溶剂，药用辅料，食品化妆品香料的添加剂，还可用于调合苹果香、菠萝香、梨香、草莓香的食用香精中,还广泛用于配置各种香水、化妆品等,近年来已受到越来越多的关注。 本论文用固体超强酸为催化剂对丙酸异戊酯的合成进行了研究。在实验过程中发现:催化剂的催化性能与催化剂本身的孔径以及比表面积有关,酸中心的浓度大催化性能好, SO42-/ZrO2存在更多的酸中心,所以SO42-/ZrO2要比其他两种的催化效率高;酯化率随催化剂用量加大而增加，当催化剂用量进一步加大，酯化率没有明显的变化；在反应时间为2.5小时前，酯化率随时间的增加而逐步增大，2.52h时,酯化率最高,2.5小时以后，酯化率开始有了下降的趋势；醇酸比为1.3:1时，酯化率达到最高96.4%，进一步提高醇酸比，则酯化率又一定程度的下降；带水剂甲苯用量为12 ml时的酯化率最高；而用苯和环己烷做带水剂时，酯化率大幅度降低,明显步能达到实验的要求。 由此得到结论：以为催化剂，用丙酸和异戊醇合成丙酸异戊酯的最佳反应条件为催化剂用量为1.4g，醇酸比为1.3:1，回流分水时间2.5 h，反应温度126 ℃~130℃，带水剂甲苯的用量为12ml，此时酯化率达到最高为96.4%。 |
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7楼2009-06-17 22:08:48
2楼2009-06-17 15:33:24
★ ★ ★
zhaoyang6650(金币+3,VIP+0):鼓励一下吧，谷歌金山词霸翻译的，很机械！ 6-17 18:23
qingfeng877680(金币+0,VIP+0):提醒下，下次使用软件翻译时请指明【机器翻译】，欢迎常来翻译互助版！ 7-9 19:29
zhaoyang6650(金币+3,VIP+0):鼓励一下吧，谷歌金山词霸翻译的，很机械！ 6-17 18:23
qingfeng877680(金币+0,VIP+0):提醒下，下次使用软件翻译时请指明【机器翻译】，欢迎常来翻译互助版！ 7-9 19:29
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Isoamyl propionate is a colorless liquid with a pineapple and pear aroma, slightly soluble in water, miscible in ethanol, ethyl ether, insoluble in glycerin. Can be used as a solvent, pharmaceutical excipients, food additives cosmetics fragrance, can also be used for blending apple flavor, pineapple flavor, pear flavor, strawberry flavor of sweet-smelling food, but also widely used to configure a variety of perfumes, cosmetics, etc., in recent years has been more and more attention. In this paper, with solid superacid as catalyst for isoamyl propionate synthesis was studied. Found in the experiment: catalyst performance and catalyst itself, as well as specific surface area of the aperture, and the concentration of acid catalyst performance, SO42-/ZrO2 more acid centers exist, so than the other two SO42-/ZrO2 high catalytic efficiency; esterification rate increased with the increase in the amount of catalyst, when further increase the amount of catalyst, the yield did not change significantly; in the reaction time of 2.5 hours ago, the yield increased with time and gradually increase , 2.52h, the highest yield, 2.5 hours, the esterification rate began a downward trend; alcohol to acid ratio of 1.3:1, the esterification rate of 96.4 percent to reach to further enhance the acid ratio, the esterification rate of decline to some extent; with the amount of water to 12 ml of toluene at the highest rate of esterification; and use of benzene and cyclohexane with water when done, a significant reduction in yield is clearly step-by-step to achieve the requirements of the experiment . This conclusion: that the catalyst with acid and isoamyl alcohol isoamyl propionate synthesis of the best reaction conditions for the amount of catalyst 1.4g, acid ratio of 1.3:1, time to return to water 2.5 h, reaction temperature 126 ℃ ~ 130 ℃, with the amount of liquid toluene 12ml, at this time the highest yield was 96.4%. |
3楼2009-06-17 16:46:33
4楼2009-06-17 18:22:46
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