3,5-二甲氧基邻苯二甲酸酐的合成与表征

3,5-二甲氧基苯甲酸与水合氯醛进行烷基化和成环反应生成(4,6-二甲氧基-7-三氯甲基)-2-苯并[c]呋喃酮,然后经水解、脱羧、氧化、脱水反应合成了3,5-二甲氧基邻苯二甲酸酐,反应总得率78%。反应的中间物和目标产物用IR,1HNMR和MS等进行了表征。用该化合物合成取代蒽醌、金丝桃素及其衍生物的研究正在进行中。     

2,4-二甲氧基甲氧基苯乙酸的合成

以2,4-二甲氧基苯乙酸为原料,经由4步反应合成了2,4-二甲氧基甲氧基苯乙酸。对目标分子和得到的中间体进行了¹H-NMR、MS表征,为合成香豆素类染料提供了新的前体化合物。     

2-氯-3,4-二甲氧基苯甲醛的合成研究

以3,4-二甲氧基苯甲醛为原料,在二氯亚砜作用下,一步反应合成得到目标产物2-氯-3,4-二甲氧基苯甲醛,其结构经1 HNMR和GC-MS确证。对影响目标产物收率的因素进行了考察,确定的最佳反应条件为:物料n(3,4-二甲氧基苯甲醛)∶n(二氯亚砜)=1∶1.3,反应溶剂为二氯甲烷,反应温度为-30℃,反应时间为16h。在此最佳反应条件下,目标产物的收率为63.4%。     

2,3-二甲氧基丙酸甲酯的合成

以丙烯酸甲酯、溴素为原料合成2,3-二溴丙酸甲酯,然后与甲醇钠反应合成2,3-二甲氧基丙酸甲酯。通过条件实验获得了较佳反应条件:n(甲醇钠)∶n(2,3-二溴丙酸甲酯)=1.8∶1.0,反应温度为20℃,反应时间为10 h。在该条件下,2,3-二甲氧基丙酸甲酯含量达68.7%(GC),精馏纯化收率达57.8%。     

3-甲氧基-5,6-二氨基-2-硝基吡啶的合成

研究了以3-氯-5-甲氧基-2,6-二硝基吡啶为原料,通过甲氧化、硝化、氨化合成3-甲氧基-5,6-二氨基-2-硝基吡啶,该化合物的结构通过IR,1H NMR,MS和元素分析进行了表征,确认为目标化合物。分析了3-甲氧基-5-氯-2,6-二硝基吡啶的氯基和硝基的反应活性。     

药物中间体3,5-二甲氧基-邻苯二甲酸酐的合成及表征

以3,5-二甲氧基苯甲酸甲酯为原料经过羟烷基化反应、酯交换反应、水解反应、脱羧反应、氧化反应、脱水反应来合成3,5-二甲氧基-邻苯二甲酸酐这一中间体,每步反应的收率均在90%以上。通过差热分析、红外、质谱、核磁等分析手段对合成的化合物的结构表征,结果表明,所合成的化合物的结构、性能指标与目标要求一致。     

3,4-二甲氧基苯乙醛的合成

以3,4-二甲氧基苯甲醛为原料,经过Darzens缩合、碱解、脱羧3步反应合成了3,4-二甲氧基苯乙醛,总收率为58.3%。并与甲醇和乙二醇分别缩合,合成了4-(2,2-二甲氧基乙基)-1,2-二甲氧基苯和2-(3,4-二甲氧基苄基)-1,3-二氧戊环两种羰基保护物。     

DTPA-双(3,5-二甲氧基-4′-氨基二苯乙烯)的合成

以3,5-二甲氧基苄溴为起始原料,通过Witting-Hornor反应,再经Fe/HCl还原,合成了3,5-二甲氧基-4′-氨基二苯乙烯。再与DTPAA反应得到标题化合物,其结构经IR、MS1、HNMR、元素分析确证。     

2,5-二甲氧基苯乙胺合成方法的改进

以锌粉和氯化高汞作还原剂、2,5-二甲氧基苯甲醛为原料,与硝基甲烷在少量吡啶存在下,合成了2,5-二甲氧基-β-硝基苯乙烯,将其还原得到目标产物2,5-二甲氧基苯乙胺。通过对不同还原剂对反应影响的讨论可知,采用锌粉和氯化高汞作还原剂总收率可提高到62·5%。     

3,4-二甲氧基苯乙醛的合成研究

以3,4-二甲氧基苯甲醛为原料,经Darzens缩合、碱解、脱羧得到3,4-二甲氧基苯乙醛,反应总收率为61.5%。通过对反应溶剂、反应时间的考察和优化,改进后的合成工艺操作更加方便、更加快捷、更适合工业化生产。     

2,3-二甲氧基-1,3-丁二烯的合成研究

选用新型催化剂及溶剂体系,通过相转移催化法在低温下合成了2,3-二甲氧基-1,3-丁二烯,采用减压蒸馏和柱层析的分离方法提高了产品纯度,通过在反应前引入吩噻嗪阻聚剂有效防止了产物聚合。实验表明:反应以十六烷基三甲基溴化铵作催化剂,v(2,3-丁二酮)∶v(原甲酸甲酯)=1∶3.5,并且在溶剂CH2Cl2中回流10h时,总收率达到77%。与文献相比,反应条件更温和,收率更高。     

Delocalized carbanions: synthesis and polymerization of 2,3-disubstituted-1,3-butadienes

Summary The 2,3-dimethylene-1,3-butadiene dianion (2) was prepared from 2,3-dimethyl-1,3-butadiene (1) using Lochmann's base (n-BuLi/potassium-t-butoxide in pentane). The dianion was reacted with primary halides to yield 2,3-disubstituted-1,3-butadiene monomers. These monomers were polymerized free radically with AIBN and with Ziegler/Natta coordination catalysts. The resulting polymers were examined by DSC for crystallization of the polymer backbone and alkyl side chains.     

微波辐射下一锅法合成3,4-乙撑二氧噻吩类化合物

首次从2,3-二甲氧基-1,3-丁二烯衍生物出发,微波辐射下采用一锅法成功合成了一系列3,4-乙撑二氧噻吩类化合物.实验表明,该法具有反应条件温和、收率高和操作简单的优点.3,4-乙撑二氧噻吩类化合物的结构经 ~1HNMR 、~13CNMR、IR和元素分析进行了表征.也讨论了原料的量、催化剂和溶剂对3,4-乙撑二氧噻吩(EDOT)收率的影响.     

“点击”化学合成1-苄基-4-三氟甲基-5-苯甲醇基-1,2,3-三氮唑

溴化苄和叠氮化钠为原料,通过叠氮化反应制得叠氮苄,反应收率达73.6%。2,3-二溴-1,1,1-三氟丙烷为原料,通过烯化、炔基化制得1-苯基-4,4,4-三氟-2-丁炔-1-醇,反应收率达75.5%。1-苯基-4,4,4-三氟-2-丁炔-1-醇和叠氮苄,在[Cp*RuCl2]n催化下通过1,3-偶极环加成反应首次合成了标题化合物,反应收率达到89.2%。产物结构经IR、1HNMR、19FNMR、13CNMR、ESI-MS和元素分析确证。     

Epoxidation of E-1,4-poly(2-triethylsilyl-1,3-butadiene) and E-1,4-poly-[2,3-bis(trimethylsilyl)-1,3-butadiene] Stereochemical analysis of E-1,4-poly(2,3-epoxy-2-triethylsilyl-1,3-butadiene) and E-1,4-poly-[2,3-bis(trimethylsilyl)-1,3-butadiene] by 13C and 29Si NMR

Summary Reaction of E-1,4-poly(2-triethylsilyl-1,3-butadiene) (I) with m-chloroperbenzoic acid (MCPBA) yields E-1,4-poly(2,3-epoxy-2-triethylsilyl-1,3-butadiene) (II). Similar reaction of E-1,4-poly[2,3-bis(trimethylsilyl)-1,3-butadiene] (III) with MCPBA gives E-1,4-poly[2,3-epoxy-2,3-bis(trimethylsilyl)-1,3-butadiene] (IV). The product polymers have been characterized by ¹H, ¹³C, and ²⁹Si NMR, IR, GPC, TGA and elemental analysis. ¹³C and ²⁹Si NMR permit Stereochemical analysis on the microstructures of II and IV.     

Coupling effect of bifunctional ZnCe@SBA-15 catalyst in 1,3-butadiene production from bioethanol

A series of bifunctional ZnCe@SBA-15 catalysts with different Zn/Ce ratios were prepared by a solid-state grinding strategy and used in the conversion of ethanol to 1,3-butadiene (ETB). For the supported metal oxides, ZnO serves as the active sites for the dehydrogenation of ethanol, and CeO₂ promotes the aldol-condensation reaction. Based on the results of Py-FTIR and NH₃-TPD, it suggests that the yield of 1,3-butadiene is positively correlated with the number of weak Lewis acid sites on the catalyst surface, given their benefit for aldol-condensation reactions. The catalyst with an optimal Zn/Ce ratio of about 1:5 has the highest concentration of weak Lewis acid. Coupling with the ZnO sites, it contributes to a 98.4% conversion of ethanol and a 45.2% selective of 1,3-butadiene under relatively mild reaction conditions (375 ℃, 101.325 kPa, and 0.54 h^-1).     

2,3-二氯苯甲醚的合成新工艺研究

以2,3-二氯氟苯和甲醇甲醇钠为起始原料,代替硫酸二甲酯法生产2,3-二氯苯甲醚的新工艺。优化工艺条件为:投料比n(2,3-二氯氟苯)∶n(30%的甲醇钠甲醇溶液)=1∶1.1,反应温度60℃,反应时间为12 h,在此条件下2,3-二氯苯甲醚收率为98.4%,2,3-二氯氟苯的转化率达100%。     

Empirical modeling of normal/cyclo-alkanes pyrolysis to produce light olefins

Due to the complexity of feedstock, it is challenging to build a general model for light olefins production. This work was intended to simulate the formation of ethylene, propene and 1,3-butadiene in alkanes pyrolysis by referring the effects of normal/cyclo-structures. First, the pyrolysis of n-pentane, n-hexane, n-heptane, n-octane, n-nonane, n-decane, cyclohexane, methylcyclohexane, n-hexane and cyclohexane mixtures, and n-heptane and methylcyclohexane mixtures were carried out at 650-800℃, and a particular attention was paid to the measurement of ethylene, propene and 1,3-butadiene. Then, pseudo-first order kinetics was taken to characterize the pyrolysis process, and the effects of feedstock composition were studied. It was found that chain length and cyclo-alkane content can be qualitatively and quantitively represented by carbon atom number and pseudo-cyclohexane content, which made a significant difference on light olefins formation. Furthermore, the inverse proportional/quadratic function, linear function and exponential function were proposed to simulate the effects of chain length, cycloalkane content and reaction temperature on light olefins formation, respectively. Although the obtained empirical model well reproduced feedstock conversion, ethylene yield and propene yield in normal/cyclo-alkanes pyrolysis, it exhibited limitations in simulating 1,3-butadiene formation. Finally, the accuracy and flexibility of the present model was validated by predicting light olefins formation in the pyrolysis of multiple hydrocarbon mixtures. The prediction data well agreed with the experiment data for feedstock conversion, ethylene yield and propene yield, and overall characterized the changing trend of 1,3-butadiene yield along with reaction temperature, indicating that the present model could basically reflect light olefins production in the pyrolysis process even for complex feedstock.     

MCPVT测定1,3-丁二烯氧化动力学

用小型密闭压力容器实验(MCPVT)分别跟踪测定了1,3-丁二烯在氮气和氧气氛围下温度随时间的变化(T-t)和压力随时间的变化(p-t)。利用p-t曲线构建了1,3-丁二烯初期氧化反应动力学。结果表明,在氮气条件下,即使温度达到388.15 K也未检测到1,3-丁二烯发生化学反应。1,3-丁二烯与氧气在343.15～363.15 K范围内发生了氧化反应,反应器内的压力减小。1,3-丁二烯与氧气的初期氧化反应动力学是二级反应。另外,还考察了氧气过量和1,3-丁二烯过量时两种特殊情况下的假一级氧化反应动力学。探讨了过渡态的热力学参数,计算结果表明,1,3-丁二烯的热氧化是一个有序的分子数减少过程。用气相色谱-质谱联用仪和碘量法分析了氧化反应产物,其产物有呋喃和过氧化物。