酸性离子液体催化甲醇脱水合成二甲醚

基于三丁基磷和1,4-丁烷磺内酯,采用两步法合成了一种含有磺酸基团的强酸性离子液催化剂,并将此离子液体用于催化甲醇脱水反应。考察了反应温度、反应时间、催化剂用量和甲醇初始溶液浓度对反应的影响。红外光谱检测确认了离子液体的分子结构。实验结果表明,该催化剂能有效地催化甲醇脱水反应生成二甲醚,反应物中没有检测到副产物,催化剂重复使用数次活性无明显降低。     

双咪唑离子液体[C_6(mim)_2](InCl_3-Br)_2催化合成二苯甲烷的研究

本文采用两步合成法合成双咪唑离子液体[C_6(mim)_2](InCl_3-Br)_2,经核磁共振(~1H NMR)对离子液体进行了表征,采用乙腈红外探针法定性分析了离子液体的Lewis酸性。将[C_6(mim)_2](InCl_3-Br)_2用于催化合成二苯甲烷,考察了温度、时间和催化剂用量等对反应的影响。结果表明:合成了双咪唑离子液体[C_6(mim)_2](InCl_3-Br)_2,双咪唑离子液体的Lewis酸性强于InCl_3,在50℃时反应5 h,离子液体用量为1 mmol时,二苯甲烷的产率为40.4%。     

Brønsted-Lewis双酸性离子液体催化合成乙酸正丁酯

以3-氨基丙磺酸、氯化锌、盐酸为原料制备了一系列Brønsted-Lewis双酸性离子液体。离子液体中阳离子磺酸基提供Brønsted酸性,阴离子提供Lewis酸性。采用FTIR、1HNMR、13CNMR、EA对合成的离子液体进行了结构表征;对离子液体的Brønsted酸性、Lewis酸性、腐蚀性进行了测定。使用该离子液体催化合成了乙酸正丁酯并利用响应曲面法考察了最佳反应条件。结果表明：反应温度103℃,催化剂[NH3C3H6SO3H]Cl/0.75ZnCl2（3-氨基丙磺酸盐酸盐与氯化锌物质的量比为1.00∶0.75）用量为正丁醇质量的10.03%,酸醇物质的量比为1.00∶1.22,反应时间4.92h,带水剂环己烷用量为正丁醇质量的20%条件下,乙酸正丁酯收率可达97.28%。[NH3C3H6SO3H]Cl/0.75ZnCl2重复使用5次后,催化剂活性没有明显降低。     

酸性离子液体[BMIM]HSO_4的合成及其性能测定

酸性离子液体作为绿色的溶剂和催化剂具有很多独特的性质,成为现今研究的热点。本文探讨了离子液体[BMIM]HSO4的最优合成条件并测定其物理性质,测定其与其它溶剂的互溶性。     

离子液体催化苯与1-十二烯烷基化的循环反应-分离实验装置

针对酸性氯铝酸盐室温离子液体［BMIM］［AlCl₄］催化苯与1-十二烯烷基化合成十二烷基苯（LAB）反应体系双液相、反应速率高和催化剂对湿气敏感的特点,建立了一套既可间歇操作也可连续操作的强制混合-反应-分离-再循环实验装置.循环物料和离子液体的混合与烷基化反应在一台静态混合反应器中进行,反应后料液和离子液体在一台液-液沉降器中进行分离.运行结果表明,在一定的物料循环和离子液体注入流量范围内,可以实现离子液体催化剂和反应料液的高效、快速混合与分离,催化剂被有效地保留在反应系统内并实现了它的再循环.     

Br?nsted酸性离子液体催化双酚芴的合成

以1-甲基咪唑、1,3-丙磺酸内酯、硫酸、磷酸、四氟硼酸、对甲苯磺酸为原料,合成4种Br?nsted酸性离子液体(ILs),通过FTIR、NMR和TG对其结构进行了表征,同时采用UV-vis测定了离子液体的酸度H0。将离子液体应用于双酚芴(BHPF)的合成反应中,离子液体的酸度H0≤1.94时有催化作用,H0≤1.69的ILs催化剂有应用价值。采用单变量优化法考察了反应参数对9-芴酮和苯酚缩合反应的影响,确定较优反应条件为:苯酚、9-芴酮和IL1的物质的量比为6∶1∶0.125,IL1和助催化剂巯基乙酸的物质的量比为5∶2,反应温度110℃,反应时间6 h。在上述条件下,考察了4种离子液体催化剂对双酚芴合成反应的催化效果,使用IL1、IL2、IL4催化反应时,9-芴酮转化率均为100%,双酚芴的选择性约为87%。此外,离子液体IL1连续使用5次催化效果无明显降低。     

SO3H-功能化酸性离子液体催化合成己二酸二丁酯

以1,3-丙烷磺内酯和1,4-丁烷磺内酯为主要原料,采用两步法合成了8种SO3H-功能化酸性离子液体,考察有/无带水剂条件下不同酸性离子液体的酸性及其对合成己二酸二丁酯的催化活性,并将离子液体酸性强弱与酸催化活性进行关联,同时对反应温度、原料配比、反应时间、催化剂用量进行优化。结果表明,优选N-(3-磺酸基)丙基咪唑硫酸氢盐离子液体为催化剂,添加带水剂环己烷,在反应温度110℃、n(1-butanol)∶n(adipic acid)=6∶1、m(cat.)/m(adipic acid)=0.015、反应时间3 h、w(cyclohexane)=15%(基于反应体系总质量,下同)的优化反应条件下,己二酸二丁酯收率为98%。     

新型环己亚胺类离子液体的合成及其催化酯化反应性能

利用环己亚胺与1,3-丙烷磺酸内酯生成的1-(3-磺丙基)环己亚胺盐,合成了2种新型Br?nsted酸性离子液体1-(3-丙磺基) 环己亚胺硫酸氢盐（[HMIPS]HSO4）和1-(3-丙磺基) 环己亚胺对甲苯磺酸盐（[HMIPS]OTs）。采用1H NMR、FT-IR、LC-ESI-MS及DSC-TG等方法对其进行了表征。结果表明,所合成的[HMIPS]HSO4和[HMIPS]OTs是一类新型的Br?nsted酸性离子液体。该类型离子液体含有环己亚胺7元环,分解温度高于260℃,其水溶液的pH值与相同浓度的硫酸水溶液的相近,具有较强的Br?nsted酸性。最后考察了所合成的新型离子液体对柠檬酸和正丁醇酯化反应的催化性能,并与传统咪唑类离子液体进行了对比。结果显示,所合成的新型离子液体具有良好的催化活性,[HMIPS]HSO4为催化剂时,在n(柠檬酸):n(正丁醇):n([HMIPS]HSO4)＝5:1:0.02,110-130℃和回流反应2 h的条件下,柠檬酸的转化率为98.3%,柠檬酸三丁酯的收率可达97.5%。而传统的咪唑离子液体[MIMPS]HSO4为催化剂时,柠檬酸的转化率和柠檬酸三丁酯的收率分别为95.8%和94.7%。[HMIPS]HSO4催化剂在重复使用10次后催化活性未见明显下降。     

酸性离子液体催化合成乙酸正丁酯研究进展

酸性离子液体作为一种环境友好型绿色催化剂在催化合成乙酸正丁酯反应中表现出收率高、选择性优、易回收、重复使用性好、腐蚀性小等优异性能成为目前催化酯化反应的研究热点之一。从Lewis酸性离子液体,Brφnsted酸性离子液体,固载化Brφnsted酸性离子液体三个方面介绍近年来酸性离子液体催化合成乙酸正丁酯的研究进展,并展望了今后的研究方向。     

聚苯乙烯负载酸性离子液体催化合成覆盆子酮的研究

在无溶剂,聚苯乙烯负载酸性离子液体(P[Vim-PS][HSO_4])为催化剂的条件下,利用苯酚和丁醇酮在酸性条件下进行Friedel-Crafts反应合成覆盆子酮。催化剂通过FT-IR、TG-DTG元素分析进行表征。与传统的合成方法相比,利用聚苯乙烯负载酸性离子液体为催化剂避免使用大量的有机溶剂,反应条件温和,反应时间短,产率高,易分离,且催化剂可循环利用,催化活性基本保持不变。     

微波辐射阴离子插层类水滑石及其阻燃性研究

采用在微波辐射条件下共沉淀法合成得到一类不同酸根插层Zn-Mg-Al阻燃类水滑石,并将获得的五种阻燃类水滑石与LDPE制成复合材料。用XRD、FT-IR和热分析表征样品进行。热分析结果表明：3^#酸根插层Zn-Mg-Al阻燃类水滑石（3^#样品）对LDPE的热氧分解试样的阻缓效果最好,热分解温度宽度达119.69℃。将3^#样品与日本、韩国及国内共5种阻燃用水滑石以及Al（OH）3、Mg（OH）2进行对比,发现样品/LDPE重量比为40/60时,3^#复合材料的极限氧指数（LOI）达到29;水平燃烧通过FH-1级;最大烟密度仅为0.24,抑烟效果好;无滴落且生成结实的残余炭层,这类水滑石可以单独作为一类高效阻燃消烟新型阻燃剂。     

Novel combustion synthesis of La3+-substituted MnFe2O4

La³⁺-substituted MnFe₂O₄ compounds have been prepared by using a novel combustion synthesis method. This process was found to yield homogeneous, finely crystalline powders without intermediate decomposition and/or calcination steps. Combustion-synthesized powders were sintered at 1000°C, and structural features of thus prepared materials were characterized by XRD analysis and FT-IR spectroscopy. The dc electrical conductivity of synthesized materials has been measured as a function of temperature up to 1000°C. The materials have shown semiconducting behavior at elevated temperatures. The ac electrical conductivity of synthesized samples was found to increase with increasing applied frequency. The dielectric constant and dielectric loss tangent have also been characterized. The article is published in the original.     

Aluminum Titanate Powder Synthesis via Thermal Decomposition of Transparent Gels

Aluminum titanate powder has been prepared through thermal decomposition of a transparent gel formed from a mixture of titanium butoxide and boehmite sol in acetic acid—butanol medium. The thermogravimetric curve of aluminum titanate precursor gel is characterized by a decomposition temperature extending up to 800°C while the constituent gels of boehmite and hydrous titania independently decompose at lower temperature. The removal of water entrapped in the gel structure heated at the above temperature is further made clear by infrared spectral data. The gel stays in the amorphous state up to 800°C, as revealed from XRD. The sintered aluminum titanate shows that grains with sizes above 2 μm are cracked while smaller ones are intact. When heated for a period of 2 h, the gel decomposes to powders with average particle sizes of 2.7 μm at 900°C and 6.5 μm at 1400°C.     

Contribution à l'étude de la dégradation photochimique du caoutchouc chloré par la lumière ultraviolette solaire. I. Etude physicochimique de i'évolution de la masse moléculaire

The esters were prepared by the acryloylation or methacryloylation of 1-formylamino-2,2,2-trichloroethanol and 1-(N-formylmethylamino)-2,2,2-trichloroethanol and characterized by the boiling point, melting point, and the IR spectra, The temperature of spontaneous thermal decomposition, the density, limiting oxygen number for continuous combustion and the glass transition temperature of the homopolymers of the titled compounds were also determined.     

耐高温焦炉煤气氨分解催化剂的研究

研究了经过改进的MgO载体对NH3分解活性和反应热稳定性的影响。在容易造成催化剂烧结的高温、水蒸气等条件下,对催化剂进行活性评价;通过超高温处理,观察催化剂活性下降情况,配合XRD分析结果以及SEM照片,发现通过ZrO2修饰载体和特定方法制备的催化剂,在高温下能够较好地抑制Ni、Co活性组分的烧结,具有良好的热稳定性。     

Graft copolymerization of nylon 6 with methylmethacrylate and methylacrylate,I. Optimum conditions of grafting and thermal behaviour of the copolymers

Nylon 6, 20 denier, monofilaments were grafted with methylmethacrylate and methylacrylate using ceric ion/sulphuric acid as initiator. Grafted nylon samples with different % graft-on were prepared by varying the reaction conditions. The thermal stabilities of these grafted samples were compared with parent nylon using dynamic thermogravimetry in air at a heating rate of 6 °C/min up to a temperature of 550 °C. The initial decomposition temperature (IDT) integral procedureal decomposition temperature (IPDT) and activation energy (E) values indicated that thermal stability decreased as a result of grafting.     

新型聚氨酯弹性体的合成及耐热性能表征

采用沙柳木粉在催化剂存在下,以一定液比进行人工降解得到沙柳木粉降解液,并利用降解液与异氰酸酯制备了新型聚氨酯弹性体.初步表征了新型聚氨酯弹性体的结构.该新型聚氨酯弹性体与其他弹性体相比具有较强的耐热性能,分解温度达527.8℃,玻璃化转变温度达189℃.这种新型聚氨酯分子排列规整,趋于线型排列.     

Thermal decomposition processes in aromatic amine-based polybenzoxazines investigated by TGA and GC-MS

Three different aromatic amine-based polybenzoxazines are subjected to thermal decomposition in a thermogravimetric analyzer. The degradation products, which are volatile compounds evaporating out of the furnace as gases, are trapped and analyzed further by a gas chromatograph which is coupled with a mass selective detector (GC-MS). All the degradation products are separated by GC and come out at different retention times, as seen in the total ion chromatogram. All the compound's mass are selectively identified by MS. The chromatograms are divided into two regions; the low column temperature region containing low molecular weight and highly volatile compounds, and the high column temperature region containing higher molecular weight and less volatile compounds. The evolved gas analysis performed by GC-MS allows us to identify the molecular weight and also the structure of the volatiles. This information is then used to illustrate the processes occurring during the thermal decomposition of aromatic amine-based polybenzoxazines.     

二氯丙烯胺的热分解动力学

用热分析的方法研究了二氯丙烯胺的热分解动力学,起始分解温度在120℃左右,并用无模式函数法计算出反应活化能、指前因子。     

Search for the Active Ingredients from a 2-Aminothiazole DMSO Stock Solution with Antimalarial Activity

Chemical decomposition of DMSO stock solutions is a common incident that can mislead biological screening campaigns. Here, we share our case study of 2-aminothiazole 1 , originating from an antimalarial class that undergoes chemical decomposition in DMSO at room temperature. As previously measured biological activities observed against Plasmodium falciparum NF54 and for the target enzyme PfIspE were not reproducible for a fresh batch, we tackled the challenge to understand where the activity originated from. Solvent- and temperature-dependent studies using HRMS and NMR spectroscopy to monitor the decomposition led to the isolation and in vitro evaluation of several fractions against PfIspE. After four days of decomposition, we successfully isolated the oxygenated and dimerised compounds using SFC purification and correlated the observed activities to them. Due to the unstable nature of the two isolates, it is likely that they undergo further decomposition contributing to the overall instability of the compound.