Synthesis of Exocyclic Trisubstituted Alkenes via Nickel‐ Catalyzed Kumada‐Type Cross‐Coupling Reaction of gem‐ Difluoroalkenes with Di‐Grignard Reagents

A practical, nickel‐catalyzed Kumada‐type double cross‐coupling reaction of gem‐difluoroalkenes with 1,4‐ or 1,5‐di‐Grignard reagents was developed. The reaction proceeded efficiently at room temperature and a variety of cyclization products, arylmethylenecyclopentanes and arylmethylenecyclohexanes, were obtained in high to excellent yields, respectively.

     

Synthesis and Properties of Hydrazino Amino Acyclic Carbenes of Gold(I), Platinum(II), Palladium(II) and Rhodium(III)

The nucleophilic addition of protected and substituted hydrazine derivatives to isonitrile complexes of gold(I), platinum(II), palladium(II) and rhodium(III) provides the corresponding hydrazino amino acyclic carbene complexes. These are characterized by their spectroscopic data, four different X‐ray single crystal structure analyses and their catalytic activity in the gold(I)‐catalyzed cycloisomerization of N‐propargylcarboxamides to alkylideneoxazolines is investigated.

     

Fe~(3+)对聚丙烯腈纤维预氧化反应的影响

在空气气氛中对含有Fe3+的聚丙烯腈(PAN)纤维进行预氧化处理,研究了Fe3+对PAN纤维氰基环构化和纤维结构的影响及其影响机理。结果表明:在相同的预氧化条件下,含有Fe3+的PAN纤维的预氧化程度较低,添加Fe3+后,减缓了PAN纤维预氧化进程;含有Fe的PAN预氧化纤维的体密度较低,氮气气氛下,热失重增加;在PAN纤维预氧化时,纤维表面的Fe元素大部分以Fe3O4的形式包覆在纤维表面,阻碍氧的扩散,延缓PAN纤维预氧化进程。     

3,4-二苯基氧化呋咱的高效合成

以苯偶酰为起始原料,通过羟胺加成、邻二肟分子内氧化关环合成了3,4-二苯基氧化呋咱。用红外、核磁氢谱、碳谱及元素分析对其结构进行了表征;研究了氧化剂种类、用量、质量分数及反应温度对成环效率的影响。在次氯酸钠水溶液(次氯酸的质量分数为7.39%)为氧化剂,次氯酸与二苯基乙二肟的摩尔比为3∶1,反应温度80℃,常压,反应时间1.5 h条件下,3,4-二苯基氧化呋咱收率达92.8%。     

3-氧环丁羧酸的合成研究

以丙酮、甲醇、溴和丙二酸二酯为起始原料,经过溴化、环合、水解及脱酸合成了3-氧环丁羧酸,4步反应总收率44.07%。产品经1H NMR、元素分析和质谱表征。改进后的方法具有操作简单、成本低等优点,适合工业化生产。     

环氧氯丙烷装置环化系统优化控制

介绍中国石化齐鲁分公司氯碱厂环氧氯丙烷装置环化反应系统由正压操作改为负压操作后,系统工艺控制参数的优化调整,减少了环化反应中的副反应,提高了环氧氯丙烷收率,降低了废水的COD值,取得了良好的经济、环保效益。     

吗啉产品探索

比较了吗啉产品生产方法，阐明了产品市场流向、国内发展状况及氮肥厂开拓该产品的前景。     

Effect of primary polymer chain rigidity on intramolecular cyclization and intramolecular crosslinking in free‐radical crosslinking monomethacrylate/dimethacrylate copolymerizations

d‐Bornyl methacrylate (BoMA) was chosen as a typical example of bulky monomethacrylate monomers, the polymerization of which led to the formation of a rigid polymer chain. To discuss the effect of primary polymer chain rigidity on intramolecular cyclization, we compared the solution copolymerization results of BoMA with 1 mol % ethylene dimethacrylate (EDMA; n = 1) and poly(ethylene glycol dimethacrylate) [CH₂?C(CH₃)CO(OCH₂CH₂)_nOCOC(CH₃)?CH₂, n = 9 (PEGDMA‐9)] with those of methyl methacrylate (MMA) with 1 mol % EDMA and PEGDMA‐9; the dependence of the weight‐average degree of polymerization on conversion for the former BoMA copolymerization systems was completely opposed to that for the latter MMA systems, and this was a reflection of a reduced occurrence of intramolecular cyclization caused by the rigidity of the primary polymer chain. The effect of primary polymer chain rigidity on intramolecular crosslinking was discussed through a comparison of both BoMA/EDMA and MMA/EDMA copolymerizations. The correlations of the intrinsic viscosity, root‐mean‐square (rms) radius of gyration, and second virial coefficient with the molecular weight were examined for both BoMA/EDMA (90/10) and MMA/EDMA (90/10) copolymerizations in a dilute solution because microgelation was observed in solution MMA/EDMA (90/10) copolymerization as a reflection of a locally extensive occurrence of intramolecular crosslinking. The logarithmic plots of both the intrinsic viscosity and rms radius of gyration versus the molecular weight for MMA/EDMA copolymerization were compared with those for the corresponding BoMA/EDMA copolymerizations. The second virial coefficients were greater than 10^?5 mol cm³ g^?2 for BoMA/EDMA copolymers, even when the conversion was very close to the gel point, whereas they were quite low, that is, less than 10^?5 mol cm³ g^?2, for an MMA/EDMA copolymer obtained at more than 15% conversion. These were ascribed to a suppressed occurrence of intramolecular crosslinking, a reflection of the lessened flexibility of the polymer main chain and a steric effect due to the bulky d‐bornyl groups. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1086–1093, 2004     

甲基丙烯酸/丙烯腈（MAA／AN）共聚物泡沫制备过程中的“原位成环”反应研究

以甲基丙烯酸（MAA）和丙烯腈（AN）为原料，通过自由基本体聚合制备了一种硬质MAA／AN共聚物泡沫。探讨了相应共聚物在发泡和热处理过程中发生的“原位成环”反应及机理，并利用差示扫描量热分析（DSC）和红外光谱（FTIR）进行了验证。结果表明：MAA／AN共聚物的DSC曲线在179．57℃有酸酐化放热反应峰。发泡和热处理以后，MAA／AN共聚物FTIR谱图中的羧羟基-OH弯曲振动峰减弱，而酸酐C-O-C伸缩振动峰加强，且出现了酸酐〉C=O的伸缩振动峰；生成了较为强烈的〉C-N弯曲振动峰；-C=N伸缩振动吸收峰略微减弱，并出现了新的-C=N-吸收谱带。说明分子链上发生了“原位成环”反应，形成的刚性酸酐环、六元酰亚胺环以及梯形结构使MAA／AN共聚物泡沫具有高闭孔率和优异的力学、耐热性能。