苯基磺酸官能化分子筛催化合成香豆素类化合物

在苯基磺酸官能化介孔分子筛催化剂作用下 ,取代苯酚和乙酰乙酸乙酯经Pechmann缩合反应合成系列取代香豆素类化合物 .该催化合成反应具有条件温和、产物容易分离、收率高等优点 .考察了不同位置取代羟基对该缩合反应的影响 .结果表明 ,间位羟基有利于香豆素衍生物的生成 ,提高反应收率 ,对位羟基次之 .证实了该固体酸催化活性位为磺酸Br nsted型质子酸     

H_2SO_4/AC无溶剂催化合成香豆素衍生物

以浓硫酸改性活性炭[H2SO4/AC(Cat)]为催化剂,在无溶剂条件下,取代酚和乙酰乙酸甲酯(2)经Pechmann缩合反应合成了5个香豆素衍生物,其结构经1H NMR,13C NMR和IR确证。以间甲酚(1a)和2合成4,7-二甲基香豆素(3a)为例,考察原料配比[r=n(1a)∶n(2)]、反应温度、Cat用量及反应时间对Pechmann反应的影响。在最佳反应条件[1a 5 mmol,r=1.0∶2.0,Cat 18%,于120℃反应3 h]下,3a收率80%。     

一水硫酸氢钠无溶剂催化合成4-甲基香豆素

NaHSO4•H2O(摩尔分数为0.1)催化下, 取代酚与乙酰乙酸乙酯(物质的量比1∶1.2)在无溶剂条件下, 通过Pechmann缩合反应, 合成了9个4-甲基香豆素衍生物, 反应时间3～5 h, 产率23%～91%, 反应条件温和、操作简便有效. 研究结果表明, 当苯酚环上取代基为一个羟基或氨基能显著加速反应, 提高产率, 苯环上更多的取代基则对反应没有促进作用; 当苯酚环上取代基为吸电子基团时, 则不发生反应或者产率很低.     

新型含香豆素骨架水杨醛类Schiff碱衍生物的合成

在无溶剂条件下,以草酸为催化剂,间苯二酚与乙酰乙酸乙酯经Pechmann反应制得7-羟基-4-甲基香豆素(1);1经硝化、还原制得3-氨基7-羟基4-甲基香豆素(2);2与取代水杨醛经缩合反应合成了四个新的含香豆素骨架水杨醛类Schiff碱衍生物,其结构经1H NMR,IR和元素分析表征.     

Phebalosin的全合成

以间苯二酚和D,L-苹果酸为原料,经Pechmann反应、Reimer-Tiemann反应、Darzens缩合反应及Wittig反应合成了Phebalosin,总收率1.3%,其结构经~1H NMR和~(13)C NMR表征.     

松木炭磺酸的制备、表征及催化性能研究

以松木屑为原料,经磷酸脱水炭化,磺化得到酸量为2.36 mmol/g的松木炭固体磺酸催化剂,用X射线衍射、红外光谱及热重分析对催化剂表征。结果表明松木屑炭化产物含有多种含氧官能团的无定型材料,有利于进一步磺化得到高酸量的固体磺酸催化剂,松木炭上磺酸基团热稳定性在200℃以上。在乙酸正丁酯的合成反应中,松木炭磺酸表现出优良的催化性能。     

吸电子基团取代的苯和三氧化硫的反应研究

研究了室温下多种吸电子基团取代的苯和三氧化硫的反应, 用^1H NMR测定反应产物. 苯甲醛, 苯甲酸, 苯磺酸, 二苯砜, 二苯甲酮等均首先得到3-磺酸衍生物, 进一步反应得到少量的3,5-二磺酸衍生物. 苯磺酸还得到少量的3,3'-二磺酸二苯砜和3,5,3'-三磺酸二苯砜. 硝基苯只能进行单磺化反应. 苯甲酸甲酯则得到磺酸取代的苯甲酸和硫酸甲酯     

取代基电子效应对芳基甲烷氧化缩合反应及产物的影响

研究了数种芳基甲烷在有机溶剂中碱催化下的氧化缩合反应,并对反应产物进行了表征,结果表明,芳基甲烷中取代基的吸电子效应影响其氧化缩合反应活性及产物结构特征,取代基吸电性越强,吸电基越多,氧化缩合越易发生,     

N,N'-二(2-羟苄基)取代咪唑烷的合成、表征及抑菌活性

利用生物活性叠加原理,将"邻羟苯基"和"咪唑烷"分子片断有机结合,以水杨醛和乙二胺为起始原料,经缩合、NaBH4还原制得N,N'-二邻羟苄基乙二胺(2),进而与芳醛类化合物缩合关环,合成了8种N,N'-二(2-羟苄基)取代咪唑烷类化合物(3a～3h). 化合物的结构经1H NMR、IR、MS和元素分析等测试技术进行了表征. 结果表明,水杨醛与乙二胺的缩合反应,可专一性地生成对称双缩席夫碱化合物(1);芳醛上的取代基对缩合关环反应有显著影响,邻、对位吸电基可使芳醛的羰基活化,有利于缩合关环反应的进行,邻、对位供电基可使芳醛的羰基钝化,不利于缩合关环反应进行. 抑菌测试结果表明,质量分数为0.1%时,N,N'-二(2-羟苄基)取代咪唑烷化合物对不同菌株的抑菌活性具有明显的特异性,对白色念珠菌、大肠杆菌的抑菌率达100%.     

环上取代基对苯乙酮和苯甲醛缩合反应的影响

苯乙酮衍生物与苯甲醛衍生物缩合制备各种查尔酮，报道了４种苯乙酮衍生物与９种苯甲醛之间相互缩合的结果，讨论了环上取代基对缩合反应的影响。苯甲醛环上取代基，除羟基外无论是吸电子基还是给电子基对缩合反应收率影响都不大；羟基处于醛基邻位和对位的苯甲醛与几种苯乙酮衍生物的缩合，多数没有得到预期的产物，或收率极低；苯乙酮环上的羟基对缩合反应影响很大，羟基超多，缩合越困难。提出了一种假设，试图解释羟基对缩合反应     

稻壳炭基固体酸催化剂的制备及其催化酯化反应性能

以热解稻壳炭为原料, 浓硫酸为磺化剂制备了固体酸催化剂. 采用X射线衍射、X射线光电子能谱、元素分析、孔结构分析和热重-质谱联用等手段对其进行了表征. 以油酸和甲醇的酯化为探针反应, 考察了磺化温度和时间对催化剂活性的影响, 探讨了反应条件对油酸转化率的影响, 并对所制催化剂的稳定性进行了研究. 结果表明, 制备该催化剂的适宜磺化温度和时间分别为90℃和0.25 h, 在该条件下制得的催化剂为无定形碳结构, 磺酸基密度为0.7 mmol/g. 该催化剂表现出较高的催化酯化反应活性, 在催化剂用量为5%、甲醇/油酸摩尔比为4、酯化温度和时间分别为110℃和2 h的条件下, 油酸的酯化率可达98.7%. 该催化剂具有较好的稳定性, 经7次连续反应后, 油酸的酯化率仍可达96.0%.     

竹炭磺酸催化一锅三组分合成α-氨基膦酸酯

以新鲜竹材为原料,经炭化和磺化制得的竹炭磺酸催化各种芳醛、芳胺和亚膦酸二乙酯一锅三组分合成α-氨基膦酸酯.结果表明:该固体酸具有催化性能好、操作简便、来源广泛和可重复利用等优点.     

以强酸性阳离子交换树脂为催化剂合成14-氧杂二环[10,3,0]十五碳烯-2

以三种类型的强酸性阳离子交换树脂(聚苯乙烯磺酸树脂、酚醛磺酸树脂和全氟磺酸树脂)为催化剂进行环十二碳-烯的普林斯反应,合成了14-氧杂二环[10,3,0]十五碳烯-2.考察了该三种树脂的催化性能,并与苯磺酸和对甲苯磺酸的催化性能作了比较.考察了孔径、粒度及反应条件(温度、时间、催化剂用量等)对聚苯乙烯磺酸树脂催化性能的影响.实验结果表明:全氟磺酸树脂和交联大孔聚苯乙烯磺酸树脂(交联度10％,孔径3.9×10²Å,比表面积20m²/g)具有良好的催化性能.     

Effect of catalysts on the reaction of an aliphatic isocyanate and water

The kinetics of the reaction of aliphatic isocyanate with water were investigated with hexyl isocyanate as a model compound. The kinetic study was carried out with a titration method to determine the concentration of the isocyanate group as a function of time. Gas chromatography was used to augment the kinetic data obtained from the titration method. The effects of an organic acid [p‐toluene sulfonic acid monohydrate (p‐TSA)], a tertiary amine {diazabicyclo[2.2.2]octane (DABCO)}, and an organotin compound [dibutyltin dilaurate (DBTDL)] on the reaction were investigated for the conversion of isocyanate to a urea. Under the reaction conditions in this study, urea was the only product observed. The rate constants indicated that p‐TSA had low catalytic activity, DABCO had intermediate catalytic activity, and DBTDL had high catalytic activity. A reaction mechanism was proposed for each of the catalysts. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1677–1688, 2002     

微波加热和常规加热下功能化离子液体催化合成丁二酸二辛酯

分别在微波辐射和常规加热下,以具有丙烷磺酸基功能基团的离子液体为催化剂催化丁二酸和正辛醇 合成丁二酸二辛酯,考察了其阴、阳离子对催化剂活性的影响.相比常规加热,微波加热提高了反应效率,缩短了反应时间.以[ PyPS]HSO4为催化剂,研究了催化剂用量、醇酸比和反应时间对酯化率的影响.结果表明:当催化剂用量为丁二酸的3wt％,酸醇比(丁二酸∶正辛醇)1∶4,反应温度150℃,反应时间15 min,功率400W时,酯化率达到95.74％.此外,微波辐射下[PyPS]HSO4催化剂重复使用6次后活性没有明显降低,酯化率仍有93.58％.     

Catalytic effects of six inorganic compounds on pyrolysis of three kinds of biomass

Six inorganic compounds, i.e., Na₂CO₃, NaOH, NaCl, Na₂SiO₃, TiO₂ and HZSM-5, have been investigated with regard to their catalytic effects on pyrolysis of three biomass species, i.e., pine wood, cotton stalk and fir wood by thermal analysis experiments. The results show that Na₂CO₃, NaOH, Na₂SiO₃ and NaCl made devolatilization occur at lower temperature regions in the pyrolysis of the three kinds of biomass, whereas TiO₂ and HZSM-5 made that occur at higher temperature regions in the pyrolysis of cotton stalk and had no obvious effects on pyrolysis temperatures of pine wood and fir wood. The basic catalysts NaOH, Na₂CO₃ and Na₂SiO₃ decreased the maximum weight loss rates while NaCl and HZSM-5 increased them and TiO₂ had no obvious effects on them. The four sodium compounds made pyrolysis of the three kinds of biomass more exothermic, which might be due to more char formation, whereas TiO₂ and HZSM-5 had minor effects on reaction heat. The catalytic effects in all aspects were roughly correlated with one another and their relationship with the basicity and acidity of the catalysts were preliminarily described and analyzed.     

Synthesis and Catalytic Applications of Sulfonic Acid Group–Functionalized Nano- and Microsilica Structures

Sulfonic acid group–functionalized nano- and microsilica with different sizes and shapes were synthesized. Silica nanospheres with an average size of 225 nm, silica microtubes, and fine silica gel were prepared and functionalized by sulfonic acid. Their catalytic activity was investigated in the three-component Biginelli reaction for the synthesis of dihydropyrimidinones.     

木粉焦CO2和H2O气化过程孔结构及反应性的变化

利用固定床实验装置,分别对木粉热解焦进行CO₂和H₂O气氛下的气化实验,并考察热解焦在经过部分气化反应后孔隙结构变化特点和气化反应特性。研究结果表明,木粉焦气化过程孔结构的变化规律与气化介质有关,CO₂气化过程以产生微孔为主,孔径大部分在0.4nm～0.9nm;而H₂O气化在反应初期以产生微孔为主,反应后期以扩孔为主;部分气化焦的反应性和比表面积关联结果显示,两者不具有简单相关性,反应性也受孔结构特性的影响。     

One-step synthesis of novel biacidic carbon via hydrothermal carbonization

The novel biacidic carbon has been synthesized via one-step hydrothermal carbonization of glucose, citric acid, and hydroxyethylsulfonic acid at 180 °C for only 4 h. The novel carbon had an acidity of 1.7 mmol/g with the carbonyl to sulfonic acid groups molar ratio of 1:3, which was confirmed by IR, XPS, TPD, SEM, and BET analyses. The catalytic activities of the carbon were investigated through esterification and oxathioketalization. The results showed that the carbon owned the comparable activities to sulfuric acid, which indicated that the carbon holds great potential for the green processes.     

Catalytic poly(vinyl alcohol) functionalized membranes obtained by gamma irradiation

Polymeric catalytic membranes bearing sulfonic acid functions have been prepared by mutual gamma irradiation at a ⁶⁰Co source, of poly(vinyl alcohol) (PVA) membranes and methanesulfonic acid. The effect of various synthesis conditions on membranes' physical–chemical properties and catalytic activity in the esterification reaction between acetic acid and isoamyl alcohol to obtain isoamyl acetate (banana flavor), was evaluated. The membranes were characterized by ATR-FTIR, TPP, AFM and SEM. Water contact angle determinations were also performed. The obtained results showed that within the range of conditions studied the increase in sulfonic acid groups' content is accompanied by an enhancement in the membranes catalytic activity, while the increase in absorbed dose leads to a decrease in catalytic activity.