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硫酸氢钠催化合成丁酸丁酯的研究 总被引：1，自引：1，他引：1
杨树 《昆明师范高等专科学校学报》2002,24(4):60-61,63
硫酸氢钠是催化丁酸与丁醇酯化反应的良好催化剂，其最佳反应条件为：催化剂用量为O．2g／0．1mol丁酸，酸醇摩尔比为1：3，反应时间1．5h，丁酸的酯化率可达99％．该催化剂催化效果好，使用量少，酯化率高，三废排放少，廉价易得，极有应用价值． 相似文献
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硫酸氢钠催化合成丁酸苄酯 总被引：2，自引：0，他引：2
研究了以硫酸氢钠为催化剂，丁酸和苄醇为原料合成丁酸苄酯，考察了影响酯化率的各种因素，确定了最佳反应条件为：丁酸用量0．1mol时，苄醇与丁酸的物质的量比为1．2，0．5g催化剂，10mL甲苯作带水剂，反应时间40min，酯化率98％以上．结果表明：硫酸氢钠是合成丁酸苄酯的优良催化剂． 相似文献
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杨树 《昆明师范高等专科学校学报》2001,23(4):67-69
利用硫酸氢钠作为酯化反应催化剂合成了己酸异戊酯，确定了其最佳反应条件为：催化剂用量为0．2g／0．1mol己酸，醇酸物质的量比为1．5：1，带水剂环己烷10mL，回流反应时间1．5h，己酸的酯化率可达99．39％。实验表明该催化剂催化效果好，使用量少，酯化率高，环境污染小，廉价易得，很有应用价值。 相似文献
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杨树 《昆明师范高等专科学校学报》2005,27(4):65-67
利用硫酸氢钠作为酯化反应催化剂合成了己酸乙酯，确定了其最佳反应条件——催化剂用量为每0．1mol己酸0．3克，醇酸物质的量比为2．5：1，以3A分子筛为脱水剂，回流反应时问为3．5h，己酸的酯化率可达98．69％．实验表明：该催化剂催化效果好，使用量少，酯化率高，环境污染小，廉价易得，用3A分子筛脱水，操作简便，较有工业应用价值． 相似文献
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杨树 《昆明师范高等专科学校学报》2004,26(4):33-35
以氨基磺酸为催化剂，催化合成了苯甲酸正丁酯，用正交实验法确定了反应的最佳条件．最佳条件为：催化剂用量为0.6g／0．1mol苯甲酸，醇酸物质的量比为2：1；回流时间为3．5—4．0h；苯甲酸的酯化率可达97．26％．该催化剂催化效果好，用量少，酯化率高，污染小，有一定的工业应用价值． 相似文献
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以正丁酸和戊醇为原料，硫酸氢钠为催化剂合成了丁酸戊酯．最佳合成条件：以0．1mol正丁酸为基准，醇酸摩尔比为1．2：1，催化剂用量0．2克，甲苯5毫升，反应时间30min，丁酸的酯化率可达99．3％，在无甲苯存在下，合成食品级丁酸戊酯，酯化率可达99．7％． 相似文献
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硫酸氢钠催化合成丁酸丁酯 总被引：1，自引：0，他引：1
以硫酸氢钠为催化剂催化正丁酸和正丁醇进行酯化反应合成了丁酸丁酯 ,讨论了反应时间、催化剂用量、酸醇摩尔比等因素对酯化率的影响 ,确定了最佳反应条件 :酸醇摩尔比 1∶1 1,催化剂用量 0 1g ,反应时间6 0min ,反应温度 12 0～ 14 0℃ ,酯化率达 98 8% . 相似文献
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以正丁酸和异丁醇为原料，固体超强酸ZrO2-SO4^2-为催化剂，催化合成丁酸异丁酯．探讨了原料醇酸摩尔比、温度、时间、催化剂用量和重复使用性等工艺条件对酯化反应的影响、实验结果表明，在最佳工艺条件下酯化率可达98％以上． 相似文献
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杨树 《昆明师范高等专科学校学报》2008,30(4):95-97
合成了复合固体超强酸SO4^2-／ZrO2-Ce2O3,研究了Ce2O3的最佳添加量,并将其应用于催化合成丁酸异戊酯的反应,探索到了最佳反应条件．Ce2O3的最佳添加量为2．0％,最佳反应条件为0．10mol丁酸使用1．0g复合固体超强酸催化剂,醇酸摩尔比2．0,反应时间为2．5h,丁酸的酯化率可达96％以上,并且不污染环境． 相似文献
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罗艳萍 《读与写:教育教学刊》2008,5(6)
The communication of people partially is the communication of cultures. Culture has a direct effect on international commercial activities in all aspects. Different conceptions about time, space, equality, law and the like, lead people to deal with things in different ways. So to know cultures of the counterpart is to facil-itate our enterprises so as to have a smooth and successful communication in commercial activity. 相似文献
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邱崇丙 《唐山师范学院学报》2014,(1):21-23
汉字的六书,《说文》对“转注”一类,语焉不详。后世学者提及转注,也仅限于许慎所举出的例字。《汉字例说》一文,作者从转注的角度综合考虑,对部分现代常用字作了分析,跟传统的解释有所不同。希望能抛砖引玉,互相切磋,以推进学术研究。 相似文献
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Richard Denner 《海外英语》2007,(4):14-15
Rosco and I wait for the fishermen to return.I sit at a wooden bench near the store at Mt.Baker Resort and watch the clouds change shape. Rosco has my belt around his neck and an eight foot tow chain hooked to a tree. Dogs must be on a leash. Ducks and rabbits are loose. 相似文献
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Given a graph G,a subgraph C is called a clique of G if C is a complete subgraph of G maximal under inclusion and |C|≥2. A clique-transversal set S of G is a set of vertices of G such that S meets all cliques of G. The clique-transversal number, denoted as TC (G), is the minimum cardinality of a clique-transversal set in G. The clique-graph of G, denoted as K (G), is the graph obtained by taking the cliques of G as vertices, and two vertices are adjacent if and only if the corresponding cliques in G have nonempty intersection. Let F be a class of graphs G such that F={G|K(G) is a tree}. In this paper the graphs in F having independent clique-transversal sets are shown and thus TC (G)/|G|≤1/2 for all G ∈ F. 相似文献
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《海外英语》2007,(5):10-11
Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help? 相似文献
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Rachel Zupek 《海外英语》2007,(11):40-41
我们绝大部分人都同意一件事情——我们喜欢金钱。但是你对金钱的喜欢之情足够到让你创立一份事业么?.财富通常被人忽视,主要在于人们不能真正了 相似文献
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陈美曦 《山东教育学院学报》2008,23(2):103-107
Different nations have different social cultures, and the social culture of every nation is developing with the development of the nation, language is greatly influenced by social culture, which enables language to possess national and historical characteristics. Word is the smallest, independent, meaningful linguistic unit of language. It can well reflect the national and historical characteristics. From synchronic aspect, the social and cultural influence on word meaning is mainly embodied in conceptual and associative meanings of word. The incorrespondence of word meaning is a phenomenon that exists in both conceptual and associative meanings of word among different languages. From diachronic aspect, the development of social culture causes some changes of word meaning to some extent. Therefore, social culture plays a key role in vocabulary learning and mastery of a language. 相似文献
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YANGShiguo 《重庆大学学报(英文版)》2004,3(1):86-88
The problem on the geometrc inequalities involving an n-dimensional simplex and its inscribed simplex is studied. Aninequality is established, which reveals that the difference between the squared circumradius of the n-dimensional simplex andthe squared distance between its circumcenter and barycenter times the squared circumradius of its inscribed simplex is not lessthan the 2(n-1)th power of n times its squared inradius, and is equal to when the simplex is regular and its inscribed siplex is atangent point one. Deduction from this inequality reaches a generalization of n-dimensional Euler inequality indicating that thecircumradius of the simplex is not less than the n-fold inradius. Another inequality is derived to present the relationship betweenthe circumradius of the n-dimensional simplex and the circumradius and inradius of its pedal simplex. 相似文献