微波有机合成及反应器的新进展

简述了微波促进有机合成反应的机理 ,讨论了微波密闭合成反应技术、微波常压合成反应技术、微波连续合成反应技术及微波干法合成反应技术在近年来的进展情况。分析了家用微波炉的缺点 ,对目前国内外实验用微波反应器在有机合成应用中的不足之处进行了评价 ,结合本教研室所做的工作 ,介绍了有机合成专用微波炉。展望了微波有机合成的发展前景。     

同步冷却技术在微波辅助有机合成中的应用

同步冷却技术作为微波化学领域的一项新技术,可以使某些有机反应速度加快,产率提高,选择性变好,因此同步冷却条件下的微波辅助有机合成成为研究的热点之一。从具有同步冷却的微波反应装置、同步冷却条件下微波辅助有机合成的反应特点、同步冷却技术在低温微波化学中的应用和该技术在研究"微波的非热效应"中的应用4个方面进行综述,总结并展望了它在微波化学中的发展前景。     

微波有机合成及反应器研究新进展

综述了近年来微波辐射技术在有机合成应用中的新进展。针对微波有机合成反应技术及专用微波反应器作了重点介绍。     

微波辅助合成聚羧酸减水剂及其性能研究

利用微波技术具有操作简便、清洁、高效、安全及靶向性等特性,分别采用微波辅助合成和常规水浴法,以甲基烯基聚氧乙烯醚(TPEG)、丙烯酸(AA)为单体合成梳状聚羧酸减水剂.通过实验,研究了微波加热对减水剂表征及性能的影响,结果表明,微波辅助合成的方法有效提高了聚合反应的转化率,可更好地控制反应进程,并对新拌浆体絮凝结构拥有更好的吸附-分散性能.     

微波辅助合成4-苯基氨基-7-氨基喹唑啉

以2-氨基-4-硝基苯甲酸和甲酰胺为原料,经Niementowski、氯代、烃化反应合成4-苯基氨基-7-硝基喹唑啉盐酸盐,再经铁粉还原得4-苯基氨基-7-氨基喹唑啉。目标化合物的结构经1HNMR、IR、MS谱表征。前三步反应采用微波辐助合成,大大缩短了反应时间,提高了反应速率和收率。     

In-situ measurement of microwave absorption properties at 2.45 GHz for the polycondensation of lactic acid

For the construction of a microwave-assisted organic synthesis plant, it is necessary to know the dielectric properties of the reaction system. Measurements of the dielectric properties of lactic acid aqueous solution, anhydrated lactic acid, oligo(lactic acid) and water, which are constituent materials in the polycondensation of lactic acid, confirm that dielectric properties decrease as reaction progresses. Calculated microwave penetration depths, obtained from the dielectric properties, show that microwaves penetrate deeply into the reaction system. This work should be useful for the development of microwave-assisted organic syntheses in the chemical industry.     

甲基丙烯酸二甲胺基乙酯的合成

研究了以甲基丙烯酸甲酯 ( MMA)和二甲胺基乙醇为原料 ,分别用二丁基二月桂酸锡和铅粉作催化剂 ,用对苯二酚和吩噻嗪作阻聚剂 ,通过酯交换反应来制备甲基丙烯酸二甲胺基乙酯 ( DMAEMA )。实验结果表明 ,以铅粉作催化剂 ,以吩噻嗪作阻聚剂 ,甲基丙烯酸甲酯∶二甲胺基乙醇∶铅粉∶吩噻嗪按 3∶ 1∶0 .0 4∶ 0 .0 1(摩尔比 ) ,温度 97～ 98℃为制备 DMAEMA较适宜的条件 ,收率可达 85.3% ,甲基丙烯酸甲酯可重复使用。     

A microwave-assisted new synthesis of sulfonylidene–sulfonamide via reactions of N-sulfonylketenimine and sodium arylsulfinates

A rapid practical microwave-assisted new synthesis of sulfonylidene–sulfonamide was developed via the one-pot, three-component reaction of sulfonyl azides, terminal alkynes, and sodium arylsulfinates catalyzed by copper(I) iodide in DMF in moderate to good yields.     

Phenothiazine derivatives as new antioxidants for the autoxidation of methyl linoleate and their reaction mechanisms

The effect of new antioxidants, such as phenothiazine derivatives, on the autoxidation of methyl linoleate was evaluated by estimating the induction period using the weighing method. Peroxide values (iodometry and IR), refractive indices, mol wts, and UV and IR spectra were measured to investigate the extent of the autoxidation. The induction period evaluated from the weighing method gives almost the same value as that from the peroxide values. It was shown that some new phenothiazine derivatives are remarkably effective antioxidants, and, besides, the mechanism for the autoxidation of methyl linoleate containing phenothiazine derivatives as antioxidants is probably of the same type as that for the substrate alone. This study also investigated the reaction mechanism of phenothiazine derivative antioxidants by determining the electron spin resonance spectra for the antioxidants in the autoxidation of methyl linoleate. Then, the following mechanism was proposed. That is, within the induction period, these inhibitors hold stable nitroxide radicals (>NO*) in the reaction between the antioxidant amino radical (>N*), produced by the reaction of the antioxidant with ROO* or O₂, and the peroxy radical (ROO*). Besides, the more superior the phenothiazine derivative antioxidant, the more inactive the antioxidant makes oxygen and the peroxy radical for the methyl linoleate autoxidation and also for the antioxidant oxidation. Presented at the 12th World Congress of ISF, Milan, 1974.     

微波辅助合称3-叔丁基-4羟基苯甲腈

通过实验探索出微波辐射对于合成3-叔丁基-4-羟基苯甲腈的最佳条件,有效的提高了传统反应的产率,缩短了反应时间,相对加热回流对环境更加友好、更加绿色。     

Microwave assisted solvent-free synthesis of dihydropyrimidinones by Biginelli reaction over Si-MCM-41 supported FeCl3 catalyst

Among the Si-MCM-41 or montmorillonite K 10 clay supported ZnCl₂, AlCl₃, GaCl₃, InCl₃ and FeCl₃ catalysts, FeCl₃/Si-MCM-41 shows best performance for the microwave-assisted synthesis of dihydropyrimidinones by the Biginelli reaction involving multicomponent condensation of aromatic aldehyde, ethyl acetoacetate and urea in the absence of any solvent. It is a promising catalyst for the microwave-assisted reaction providing high product yield in a short period (3.0–5.0 min).     

丙烯酸高级酯的微波合成与结构表征

以丙烯酸、十二醇、十四醇、十六醇、十八醇为原料,采用微波辅助合成技术分别制备了丙烯酸十二酯、丙烯酸十四酯、丙烯酸十六酯和丙烯酸十八酯。考察了微波功率、辐射时间和原料配比等反应条件对不同长链酯酯化产率的影响,并对它们的物理性质、元素组成和分子结构进行了测定与表征。结果表明,微波辅助合成技术能高效、快速地合成丙烯酸高级酯,但各高级酯的最佳微波酯化条件明显不相同,随着高级酯碳链的增长,微波功率、辐射时间和酸醇摩尔比增大,在优化的微波合成条件下,反应速率可提高20倍以上,酯产率≥96%,且所得产物的物理性质、分子结构与传统方法加热制备的产物无明显差异。     

Solvent-free synthesis of tri-substituted thiophenes via thio-Claisen rearrangement under microwave irradiation: A convenient route to novel tertiary 2-thienyl amines

A solvent-free, solid-supported, and microwave-assisted thio-Claisen rearrangement of S-propargylated thioamides having an activated α-methylene group has been developed. The methodology could be used successfully for the synthesis of tri-substituted thiophenes and sulfur containing triarylamines. The reaction takes place in short time and in good isolated yield.     

等效介电系数经验公式在微波加热计算中的应用

微波加热化学反应所产生的部分特殊现象至今仍没有得到合理解释,非热效应成为一个悬而未决的热点问题.同时,缺少一种真正意义上对微波化学反应器设计的指导理论.因而急需一种微波加热过程中的数值模拟方法来定量研究这些问题.本文利用黄卡玛等提出的经验公式计算得到任意温度和反应时刻的丙酮碘化反应过程中混合溶液的等效介电系数,联合求解了化学反应方程、Maxwell方程和热传导方程,得到反应过程中的电磁场与温度分布.计算结果与实验结果吻合较好,验证了这种数值方法的合理性.为微波加热化学反应的数值模拟提供了一种有效的新方法,并为进一步解释部分特殊现象和进行非热效应的相关机理研究提供可能.     

微波在化工过程中的研究及应用进展

与传统加热过程比较，微波辅助有机合成的优势在于加快反应速率、提高产率和改变化学选择性。研究者们将这种常规加热无法重现的现象称为非热效应，但关于非热效应的存在性一直争论不休，至今微波促进合成反应的作用机理尚不清楚。总结了微波技术在有机合成和化工分离过程的应用进展，综述了近年来国内外对微波热效应与非热效应的研究进展，阐述了微波效应的实例分析以及理论观点，同时，对微波在工业化过程的发展进行了分析与展望。     

Microwave-assisted one-pot synthesis of metal/metal oxide nanoparticles on graphene and their electrochemical applications

An effective synthesis strategy of hybrid metal (PtRu)/metal oxide (SnO₂) nanoparticles on graphene nanocomposites is developed using a microwave-assisted one-pot reaction process. The mixture of ethylene glycol (EG) and water is used as both solvent and reactant. In the reaction system for the synthesis of SnO₂/graphene nanocomposite, EG not only reduces graphene oxide (GO) to graphene, but also results in the formation of SnO₂ facilitated by the presence of a small amount of water. On the other hand, in the reaction system for preparation of PtRu/graphene nanocomposites, EG acts as solvent and reducing agent for reduction of PtRu nanoparticles from their precursors and reduction of graphene from graphene oxide. Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM) characterizations confirm the feasibility of the microwave-assisted reaction system to simultaneously reduce graphene oxide and to form SnO₂ or PtRu nanoparticles. The as-synthesized SnO₂/graphene hybrid composites show a much higher supercapacitance than the pure graphene, and the as-prepared PtRu/graphene show much better electrocatalytic activity for methanol oxidation compared to the commercial E-TEK PtRu/C electrocatalysts.     

超细碳酸钡粉体制备方法的研究进展及展望

综述了超细碳酸钡粉体制备方面的研究进展。详细介绍了超重力法、液相沉淀法、微乳液法、均相沉淀法、模板法、低温固相合成法、微波辅助合成法等不同方法在超细碳酸钡制备中的应用与研究,对各种方法的优缺点作了具体的讨论和分析,并提出了超细碳酸钡粉体制备方法的发展方向。     

微波辅助合成5-[4-(4-溴代丁氧基)苯基]-10,15,20-三对甲氧基苯基卟啉

探讨采用微波辅助合成尾式卟啉（p-BrTMOPP）的制备工艺及其影响因素。以吡咯、对羟基苯甲醛和对甲氧基苯甲醛为原料,以丙酸为溶剂,制备得到p-HTMOPP;以1,4-二溴丁烷为原料,微波辅助加热条件下制备得到目标化合物尾式卟啉p-BrTMOPP;目标产物经过UV-vis、IR、ESI-MS等方法表征。在90℃、DMF溶剂条件下微波辐射加热30min,快速高效得到目标化合物,反应产率89.2%。和传统加热方法相比较,微波辅助合成尾式卟啉化合物明显缩短了反应时间,提高了反应效率。     

Porous ZnO-ZnSe nanocomposites for visible light photocatalysis

We report the synthesis of porous ZnO-ZnSe nanocomposites for use in visible light photocatalysis. Porous ZnO nanostructures were synthesized by a microwave-assisted hydrothermal reaction then converted into porous ZnO-ZnSe nanocomposites by a microwave-assisted dissolution-recrystallization process using an aqueous solution containing selenium ions. ZnO and ZnSe nanocrystallites of the nanocomposites were well-mixed (rather than forming simple core-shell (ZnO-ZnSe) structures), particularly, in the outer regions. Both ZnO and ZnSe were present at the surface and exposed to the environment. The porous ZnO-ZnSe nanocomposites showed absorption bands in the visible region as well as in the UV region. The porous ZnO-ZnSe nanocomposites had much higher activities than the porous ZnO nanostructures. Control experiments using cutoff filters revealed that the main photocatalytic activity of the synthesized nanostructures arose from photo-excitation of the semiconductor (ZnO or ZnSe) via absorption of light of an energy equal to or exceeding the band gap energy.     

改性分子筛处理废水中铬离子

采用微波辅助合成方法制备超微4A分子筛,将制备的超微4A分子筛用于吸附废水中的铬离子,并对可能影响其吸附效率的因素如pH和吸附温度进行探讨.结果表明,微波法合成了性能优异的超微4A分子筛.吸附溶液中铬离子试验研究表明,在溶液中含铬离子浓度400 mg·L-1、pH =4、常温和吸附时间10 min条件下,分子筛对铬离子...