Mg/Al水滑石催化碳酸二甲酯与苯酚酯交换反应

Mg/Al水滑石催化碳酸二甲酯与苯酚酯交换反应     

Methylation of Aniline and Its Derivatives with Dimethyl Carbonate under the Action of Zeolite FeHY-mmm

Russian Journal of Organic Chemistry - Selective methylation of aniline and its derivatives with dimethyl carbonate under the action of binder-free micro-, macro-, and mesoporous zeolites FeHY-mmm...     

Selective O-Methylation of Phenol with Dimethyl Carbonate over Catalysts Supported on CaO

Kinetics and Catalysis - In this work CaO-based catalysts were found to be efficient heterogeneous catalysts for the methylation of phenol with dimethyl carbonate (DMC) in a closed high pressure...     

Methylation of Aniline Over SAPO-11

Methylation of aniline over a mildly acidic siliconaluminium phosphate catalyst (SAPO-11) with medium pores is reported. The selectivity of N-methylates products is about 90%. By comparison with results obtained from SAPO-5 with large pores and with amorphous aluminium phosphate, molecular sieves with medium pores prevent the formation of bulky isomers and better resist formation of coke. The ortho isomer is most abundant among toluidine isomers. Some ortho isomers may result from the rearrangement of N-methylaniline.     

钛酸酯催化碳酸二甲酯与苯酚酯交换反应

The transesterification of phenol and dimethyl carbonate (DMC) to diphenyl carbonate (DPC) was studied using tetrabutyl titanate and tetraphenyl titanate as catalysts. The main product was found to be methyl phenyl carbonate (MPC) which is an intermediate of the reaction. The selectivity for DPC was improved when increasing the phenol/DMC molar ratio or prolonging the reaction time. The phenol conversion, selectivity for MPC and DPC were 47 4%, 90 9% and 9 14%, respectively, when the transesterification reaction approached equilibrium under the conditions of 175 ℃, 25 h and DMC∶phenol∶ Ti(OBu) 4 molar ratio of 1 5∶1∶0 05. The selectivity for DPC could reach 12.2% when the reaction time was 30 h. The tetrabutyl titanate catalyst showed a higher catalytic activity than tetraphenyl titanate.     

Methylation of Cyanidin-3-O-Glucoside with Dimethyl Carbonate

The approach presented in this study is the first for the hemisynthesis of methylated anthocyanins. It was possible to obtain cyanidin-3-O-glucoside derivatives with different degrees of methylation. Cautious identification of 4′-, 5-, and 7-OH monomethylated derivatives was also accomplished. The methylation agent used was the “green chemical” dimethyl carbonate (DMC), which is characterized by low human and ecological toxicity. The influence of the temperature, reaction time, and amount of the required diazabicyclo[5.4.0]undec-7-en (DBU) catalyst on the formation of the products was examined. Compared to conventional synthesis methods for methylated flavonoids using DMC and DBU, the conditions identified in this study result in a reduction of reaction time, and an important side reaction, so-called carboxymethylation, was minimized by using higher amounts of catalyst.     

超声波技术制备功能化二氧化硅在苯酚和碳酸二甲酯甲基化反应中的应用

Porous silica modified with -（CH2）3NH2 （primary amine）, -（CH2）3NHCH2CH2NH2 （secondary/primary amine） and -（CH2）3N-cycl-（CH2）4 （tertiary amine） were synthesized by ultrasonic technique under mild conditions. The samples were characterized by BET, elemental analysis and TG, showing that the organosilane moieties were grafted onto the surface of porous silica by covalent bond. The structure of the organosilane moieties and ultrasonic treatment time were all significant for the quantities of grafted amino groups. The samples exhibited promising catalytic properties towards the methylation reaction of phenol with dimethyl carbonate （DMC）. The methylation reaction with the modified samples featured high selectivity at high conversion. The samples were subjected to utilization for a few recycles without obvious loss of activity to indicate that ultrasonic technique was effective for the preparation of organically modified porous silica catalysts.     

苯胺与碳酸二甲酯反应合成苯氨基甲酸甲酯

 在系统研究PbO催化剂对苯胺与碳酸二甲酯反应合成苯氨基甲酸甲酯（MPC）的催化性能的基础上，考察了不同载体负载的PbO的催化性能，筛选出活性较高的SiO2载体．以SiO2为载体，考察了不同活性组分对MPC合成的催化性能，优选出了具有较高催化活性的In2O3／SiO2催化剂．在该催化剂的催化下，苯胺转化率可达75．98％，MPC选择性为78．24％．     

钒-铜复合氧化物催化碳酸二甲酯和苯酚酯交换合成碳酸二苯酯

采用共沉淀法制备了一种用于碳酸二甲酯与苯酚酯交换合成碳酸二苯酯的新型钒-铜复合氧化物催化剂.考察了V/Cu配比对催化剂性能的影响以及催化剂的重复使用效果,并用X射线衍射对催化剂的结构进行了表征.结果发现,在焙烧温度为550℃,V∶Cu摩尔比为4∶1条件下制得催化剂的活性最高,该催化剂上苯酚的转化率为37.0%,甲基苯基碳酸酯及碳酸二苯酯的总选择性为96.8%.由X射线衍射表征结果可知,该催化剂的物相组成为V2O5和CuV2O6.催化剂使用三次后苯酚转化率从37.0%降至23.7%,多次重复使用后的催化剂在空气气氛中焙烧即可再生,再生催化剂的催化性能几乎和新鲜催化剂相当,其苯酚转化率达到36.2%.     

茂钛类络合物催化碳酸二甲酯和苯酚酯交换反应合成碳酸二苯酯的研究

首次将二氯二茂钛用于碳酸二甲酯和苯酚酯交换合成碳酸二苯酯的反应, 发现二氯二茂钛对该反应来讲是一种性能优良的催化剂; 和钛酸酯类催化剂相比, 茂钛类催化剂在空气中更稳定, 从而更适合于工业化应用. 同时探讨了不同种类茂钛类化合物的催化性能, 发现位阻效应、环戊二烯环的电子分散效应以及取代基的吸电子效应等, 都会影响中心钛原子的Lewis酸性以及相应的催化活性. 总体来讲, 位阻效应越小、环戊二烯环的电子分散效应越大、与中心钛原子连接的取代基的吸电子能力越强, 越有利于反应的进行.     

Zn-Al水滑石催化碳酸二甲酯与苯酚酯交换反应的研究

用共沉淀法制备了Zn-Al水滑石,并用于多相催化酯交换合成碳酸二苯酯的反应.研究了不同n(Zn)/n(Al)比的水滑石及其焙烧产物等对酯交换反应的催化活性.结果表明,Zn-Al水滑石催化剂对该反应的催化活性和选择性很高,当n(Zn)/n(Al)=3时,在150～180℃,n(PhOH)/n(DMC)=2,催化剂用量为反应物总质量的1.5%,在反应时间为12h的条件下,DMC的转化率达到55.9%,DPC和MPC的收率分别为25.3%和27.0%,酯交换产物的选择性达到93.6%.利用XRD,TG-DTA和TEM等手段对催化剂进行了表征.     

阳离子掺杂水滑石的制备及其性质研究

研究了掺杂阳离子水滑石的制备及阳离子对水滑石性质的影响. 分别制备了掺杂Zn2+、Ni2+、Fe3+型的水滑石, 考察了掺杂阳离子对水滑石晶相结构、层间距、层间阴离子含量、水滑石表面形态、水滑石碱性的影响, 结果表明, 由于阳离子的引入, 导致水滑石层间距减小及层间阴离子结合量降低, 且使水滑石培烧产物电负性提高, 并最终降低其碱性. 以上述水滑石培烧产物作为固体碱催化剂促进苯甲醛和丙醛缩合, 合成α-甲基肉桂醛, 关联了水滑石培烧产物碱性与反应活性的关系.     

苯酚和碳酸二甲酯反应产物的气相色谱分析

苯酚和碳酸二甲酯反应产物的气相色谱分析;碳酸二苯酯;碳酸二甲酯;气相色谱     

催化剂对碳酸二甲酯与苯酚酯交换反应的影响

甲基苯基碳酸酯;碳酸二苯酯;催化剂对碳酸二甲酯与苯酚酯交换反应的影响     

磁性纳米镁铝水滑石的合成及表征

将磁性物种与镁铝水滑石进行复合,利用共沉淀法合成出粒径为20－50nm磁性纳米镁铝水滑石。样品的XRD及热分析结果表明,镁铝水滑石掺入磁性物种后并没有改变其层状结构和2个阶段质量损失的典型特征,样品的磁学性能测试结果表明,样品的比饱和磁化强度随磁性物种含量的增加而线性递增,这为层状材料与磁性物种进行复合制备新型功能材料提供了实验依据。     

一种催化碳酸二甲酯与苯酚酯交换合成碳酸二苯酯的多相催化剂

 用浸渍法以SiO2为载体制备了负载型杂多化合物催化剂CuPMo/SiO2，用于DMC和苯酚酯交合成碳酸二苯酯的反应，显示出较高的活性和高选择性. 负载量和煅烧温度煅烧温度影响催化剂活性. 在合适的反应条件下，反应8小时，苯酚转化率可达25.2%，酯交换选择性为99%.     

二丁基二月桂酸锡催化碳酸二甲酯和苯酚酯交换反应研究

研究了二丁基二月桂酸锡催化碳酸二甲酯和苯酚酯交换反应的活性和选择性,发现不同厂家生产的二丁基二月桂酸锡对该反应的催化活性和选择性差异较大,采用反应分离一体化的工艺可提高苯酚的转化率。     

乙酰丙酮氧钛催化苯酚和碳酸二甲酯的酯交换反应

首次将乙酰丙酮氧钛用于苯酚和碳酸二甲酯的酯交换反应合成碳酸二苯酯,显示出较好的催化活性和很高的酯交换选择性,催化剂经180℃热处理后,苯酚转化率可达45.8%,转化数(n(苯酚)/n(Ti))为96,高于有机钛类均相催化剂.结果表明,当乙酰丙酮氧钛用量为0.2g以上,开始有副产物苯甲醚生成,酯交换选择性随催化剂用量的增加而降低.该催化剂重复使用5次后,苯酚转化率仍可达40%以上,酯交换选择性为99.9%,表现出较高的重复使用性能.     

碳酸二甲酯与苯酚酯交换合成碳酸二苯酯的热力学性质及均相催化剂

在298.15K,101.325kPa条件下,液态碳酸二甲酯(DMC)的标准Gibbs自由能和熵分别估算为-472.3kJ*mol-1和245.2J*mol-1*K-1.在298K～523K计算了由DMC和苯酚生成碳酸二苯酯(DPC)和苯甲醚反应的热力学性质(ΔrH0m,ΔrS0m,ΔrG0m和平衡常数).计算出的热力学性质表明,DMC和苯酚酯交换合成DPC反应是吸热的,并且在热力学上是不利的.研究了n-Bu2SnO, Ti(OC4H9)4, AlCl3和ZnCl2四种酯交换法合成DPC反应的催化剂,其中n-Bu2SnO具有最高的催化活性.热力学计算和实验结果均表明,合成DPC反应的最佳温度为453K.当以n-Bu2SnO为催化剂,n(苯酚)∶n(DMC)＝4∶1时,DPC的产率和选择性分别为43.0%和88.7%.     

碳酸二甲酯与苯酚酯交换法反应精馏合成碳酸二苯酯的定量分析

采用OV-101毛细管色谱柱分别对碳酸二甲酯与苯酚酯交换法反应精馏塔底产物和塔顶馏分进行了定量分析。以苯甲酸乙酯为内标物,一次性同时分析了塔釜产物中各组分含量。碳酸二甲酯、碳酸二苯酯和苯甲醚与内标物的峰面积比与各标准品的质量百分比浓度呈良好的线性关系,回归方程分别为Y=48．92X＋0．69、Y=32．82X-1．75和Y=13．17X＋0．07,相关系数分别为0．9976,0．9972和0．9978;以丙酮为内标,对塔顶馏分进行了定量分析。DMC的回归方程为Y=150．57X＋0．37,相关系数为0．9985;甲醇的回归方程为Y=71.20X-0.07,相关系数为0．9996。精密度实验表明,4次平行测定结果重复性良好,各待测物的相对标准偏差都小于2．00％;准确度结果表明,各待测物真实值与测定值的相对标准偏差在0．33％～1．50％之间,该法准确可靠。