酸催化废油脂酯交换反应制备脂肪酸甲酯的探索

本实验以价格低廉的木质素和浓硫酸为原料,首次合成木质素磺酸催化剂,用高酸度油脂与甲醇在此催化剂作用下发生酯交换反应制备脂肪酸甲酯.实验主要考察甲醇用量、催化剂用量、反应温度和反应时间等因素对酯交换反应的影响,通过正交实验分析得出脂肪酸甲酯的最佳制备工艺条件为:甲醇用量20％,反应温度95℃,催化剂用量2.5％,硫酸用量2.0％,反应时间为9h.该条件下反应转化率可达94.33％.     

NaF/Al_2O_3催化餐饮废油制备生物柴油的研究

生物柴油是以动、植物油脂为原料,与甲醇等低级醇发生酯交换反应而制得的产物,是一种环境友好的可再生能源.实验探讨了NaF/Al2O3催化餐饮废油与甲醇的酯化反应,利用正交实验、单因素实验讨论醇油比、催化剂用量、反应温度、反应时间等因素对生物柴油产率的影响.实验结果表明制备生物柴油的最佳工艺条件为:醇/油摩尔比为9:1、催化剂用量2%(质量分数)、反应温度62℃、反应时间90分钟.在最佳工艺条件下产率可达90%以上.     

氧化钙负载氟化钾催化动物废油脂制备生物柴油研究

采用浸渍法制备KF/CaO固体碱催化剂,并应用于动物废油脂-甲醇的酯交换反应中,考察了催化剂的制备及酯交换反应的条件.试验表明:当CaO用质量比为30%的KF溶液浸渍8h,560℃焙烧4h,醇/油摩尔比为7:1,反应温度为80℃,时间2.5h,催化剂用量为油脂质量的1.6%时,酯交换反应的转化率可达92.3%,且生物柴油易分离,主要指标符合要求.     

餐饮废油催化转化制取生物柴油研究

研究了餐饮废油在甲醇钠的催化作用下制取生物柴油的工艺条件,实验表明其酯交换过程的最佳工艺条件是醇油物质的量比为7∶1、反应时间为1.5 h、催化剂质量为废油的1.5%及反应温度为60℃。通过对生成的生物柴油作理化性质检测,结果表明,其质量指标完全符合柴油优级品的标准。     

酸性离子液体[HNMP][HSO_4]催化潲水油制备生物柴油的研究

制备了酸性离子液体[HNMP][HSO4],用于催化潲水油制备生物柴油,并研究了实验过程中的反应时间、反应温度、醇油摩尔比、剂油摩尔比等因素对酯交换反应转化率的影响,确定了较适宜的反应条件。结果表明:在反应时间为4h,反应温度为140℃,醇油摩尔比为11,剂油摩尔比为0.08条件下,酯交换反应转化率为90.28%。     

TiO2纳米材料催化PBT合成的工艺条件的探讨

用溶胶－凝胶法制备TiO2纳米材料，作为PBT合成催化剂，探索其合成的工艺条件。纳米TiO2催化PBT合成的工艺条件为：PH值在5左右，酯交换温度为180－190℃，真空度越高越好（要求在90Pa以下）。     

非光气法生产碳酸二甲酯工艺进展

介绍了酯交换法、甲醇氧化羰化法生产碳酸二甲酯的原理、工艺路线及研究进展.对甲醇气相氧化羟化工艺进行评述,并与液相氧化羰基化法工艺对比,分析预测其发展前景.     

利用植物油脚-皂脚制备生物柴油的研究

以植物油脚-皂脚为原料,采用酸化、酯化、酯交换的方法来制取生物柴油。通过正交实验得到酸化植物油脚-皂脚与甲醇酯化、酯交换的最佳工艺条件:醇油脚比为6∶1,催化剂用量4%,反应温度65℃,反应时间4 h,脂肪酸甲酯的收率达到76.8%,酸值为0.5 mg KOH/g。制备的生物柴油,其主要性能指标与0#柴油接近,比其他柴油组分的调和性好,具有较好的社会经济效益。     

PET/对羟基苯甲酸共聚酯的合成及热致液晶性的讨论

介绍了制备对乙酰氧基苯甲酸的方法。合成PET(聚对苯二甲酸乙二脂)/PHB(对羟基苯甲酸)共聚酯动力学过程分析表明,先酸解和酯交换反应,而后才进行脱醋酸的缩聚反应,升高温度和加入催化剂加速缩聚反应和提高分子量。应用DSC、TBA毛细管粘度计等对共聚酯的玻璃化温度、熔点、熔体粘度等进行了考察,说明PHB量高于35％摩尔时具有热致液晶性。从消光温度、不熔的刚性链长度及PET与PPHB不能进行酯交换反应3个方面,讨论了热致液晶的条件和物理交换的问题。     

SIPE合成工艺条件研究

以间苯二甲酸二甲酯-5-磺酸钠(SIPM)和乙二醇(EG)为原料,在一定的温度和催化剂条件下进行酯交换反应制备常用聚酯染色改性剂间苯二甲酸双羟乙酯-5-磺酸钠(SIPE)。用高效液相色谱(HPLC)法测定转化率,系统研究了反应温度,时间,催化剂类型及用量,物料的摩尔配比等因素对SIPE转化率的影响。实验结果表明,获得较高SIPE转化率的最佳工艺条件为:EG/SIPM摩尔比为10.6,0.4%的Zn(Ac)2做催化剂,175℃,反应2h。     

聚合物支载的15-冠-5的合成

本研究给出高分子冠醚化合物的一种新合成方法——用烯丙氧基化的聚苯乙烯作为合成冠醚的前体，在NBS存在下与三缩四乙二醇加成，然后关环生成聚合物支载的15-冠-5。     

化工原理教学中突出知识的分析与综合

分析与综合是重要的科学思维方法。在化工原理课程理论体系的展现过程中,知识的分析与综合方法得到了充分的体现。在综合目的指导下展开课程理论体系的分析,在分析结果基础上进行工程知识的综合,并且分析与综合互相渗透和转化。教师进行教学设计和授课时,结合典型的工程问题,灵活地彰显知识的分析与综合的方法及过程,对于培养学生从理论深度上理解工程问题性质和从工程角度上掌握工程问题处理方法,有着重要的意义。     

Woodward’s synthesis of vitamin B<Subscript>12</Subscript>

The synthesis of this molecule was a landmark in organic synthesis. It involved the masterful control of shapes of molecules to create 9 chiral centres with known absolute and relative configurations. The concepts of absolute and induced asymmetric synthesis are here explained.     

Molecule matters The Quinine story: A 100-year saga

Ever since its isolation in 1820, Quinine has played a crucial role in the development of organic chemistry, chemical industry and modern medicine. The total synthesis of quinine, widely regarded as anevent of epochal importancewas claimed by Woodward and Doering in 1945. This work, however, heavily relied on unsubstantiated literature reports and it appears that Woodward’s work fell short of a total synthesis of quinine. The first stereoselective total synthesis of quinine was accomplished only in 2001, by Stork, who incidentally is the originator of the concept of stereoselectivity in total synthesis. Naturally, this work has been attested as a landmark in organic synthesis by leaders in the field.     

有机合成的一个热点问题--固相合成

介绍了固相合成的提出及发展，固相合成在一些重要有机反应中的应用。指出固相合成技术在有机分子合成中的应用前景。     

Molecule matters

Ever since its isolation in 1820, Quinine has played a crucial role in the development of organic chemistry, chemical industry and modern medicine. The total synthesis of quinine, widely regarded as an event of epochal importance was claimed by Woodward and Doering in 1945. This work, however, heavily relied on unsubstantiated literature reports and it appears that Woodward’s work fell short of a total synthesis of quinine. The first stereoselective total synthesis of quinine was accomplished only in 2001, by Stork, who incidentally is the originator of the concept of stereoselectivity in total synthesis. Naturally, this work has been attested as a landmark in organic synthesis by leaders in the field.     

优秀PS合成图片作品应具备的四个要素

图片合成作品是摄影师、后期编辑师的艺术创作成果,更是科技进步在摄影领域的应用成果。从传统的暗房合成,到现在流行的数码合成,技术进步起到关键的作用。艺术性是图片合成的灵魂,技术性是图片合成的手段。一幅优秀的合成图片作品,既要有完美的艺术构思,又要有精湛的技术手段,是技术与艺术的和谐统一体。笔者认为,优秀PS合成图片作品必须注重的四个要素是:整体构思与设计、合理选片与精心制作、不可轻略的制胜细节、恰到好处的技巧应用。     

Children's application of simultaneous and successive processing in inductive and deductive reasoning problems: Implications for developing scientific reasoning skills

The research reported in this article was undertaken to obtain a better understanding of problem solving and scientific reasoning in 10-year-old children. The study involved measuring children's competence at syllogistic reasoning and in solving a series of problems requiring inductive reasoning. Children were also categorized on the basis of levels of simultaneous and successive synthesis. Simultaneous and successive synthesis represent two dimensions of information processing identified by Luria in a program of neuropsychological research. Simultaneous synthesis involves integration of information in a holistic or spatial fashion, whereas successive synthesis involves processing information sequentially with temporal links between stimuli. Analysis of the data generated in the study indicated that syllogistic reasoning and inductive reasoning were significantly correlated with both simultaneous and successive synthesis. However, the strongest correlation was found between simultaneous synthesis and inductive reasoning. These findings provide a basis for understanding the roles of spatial and verbal-logical ability as defined by Luria's neuropsychological theory in scientific problem solving. The results also highlight the need for teachers to provide experiences which are compatible with individual students' information processing styles.     

Polymer nanocomposites

The synthesis of polymer nanocomposites is an integral aspect of polymer nanotechnology. By inserting the nanometric inorganic compounds, the properties of polymers improve and hence this has a lot of application depending upon the inorganic material present in the polymers. Solvent casting is one of the easiest and less time consuming methods for the synthesis of polymer nanocomposites. In this article we present different types of polymer composites, methods of synthesis, characterisation techniques and different applications of polymer composites. A Lagashetty is Head, Department of Engineering Chemistry, Appa Institute of Engineering and Technology, Gulbarga, Karnataka. His research interests are synthesis, characterization and applications of nanomaterials and polymer nanocomposites. A Venkataraman is Head, Department of Materials Science, Gulbarga University, Gulbarga. His research interests are nanomaterials, nanomaterials as sensors, polymer synthesis and polymer nanocomposites.     

α-熊果苷合成研究进展

α-熊果苷对黑色素合成酶-酪氨酸酶具有很好的抑制作用,对人体肌肤的美白作用是β-熊果苷的10倍以上,并且不会抑制人体细胞的生长,无毒副作用;介绍了3种合成α-熊果苷的方法,植物细胞组织作为生物反应器法、微生物细胞转化法、酶合成法;其中与酶工程相联系的转基因微生物生产α-熊果苷和手性催化剂催化合成α-熊果苷是未来主要的发展方向。