Novel polyarylates containing aryl ether units: synthesis,characterization and properties

To improve the processability of the poly(p‐hydroxybenzoic acid), copolyarylates containing m‐aryl ether units were synthesized using p‐acetoxybenzoic acid, 1,4‐diacetoxybenzene and 1,3‐bis(4'‐carboxyphenoxy)benzene by melt transesterification reaction. The structure and properties of these polyarylates were characterized using infrared spectra, differential scanning calorimetry, thermogravimetric analyses, wide‐angle X‐ray diffraction and polarized optical microscopy etc. The results showed that all polyarylates were semicrystalline materials and could form a thermotropic liquid crystalline intermediate state. As the content of aryl ether units increased, the crystallization and melting temperatures of the polyarylate decreased; meanwhile, the crystalline ability became lower. The introduction of the aryl ether could restrain the formation of a liquid crystalline structure and reduce the thermal stability to some extent. After solid state polymerization (SSP), the intrinsic viscosity, melting temperature, crystallinity and thermal stability of the polyarylate increased while the melting range narrowed. However, the SSP reaction might be accompanied by degradation and crosslinking.     

硼改性酚醛树脂在摩擦材料上的应用

用硼化合物对酚醛树脂进行改性，使硼元素以结合键形式存在于酚醛树脂中，提高酚醛树脂的耐热性，应用于摩擦材料，使其摩擦系数稳定，磨损率低。     

氨基硫脲纤维素负载钯配合物的制备及其对Heck反应的催化性能

通过较简单的方法合成了氨基硫脲纤维素负载钯配合物(CC-TSC-Pd)催化剂,并利用X射线光电子能谱、热重-差热分析等手段对其进行了表征。该催化剂在室温至240℃内热稳定性很好,在低温、空气氛围、水溶剂中能有效催化丙烯酸或苯乙烯与芳基碘(或带取代基的芳基碘)的Heck反应,立体选择性地生成反式肉桂酸(或带取代基的反式肉桂酸)或1,2-二苯乙烯,在110℃下反应5～6h,产物的收率在90.0%以上。CC-TSC-Pd催化剂具有较好的重复使用性能,连续使用5次,反式肉桂酸的收率仍可达76.3%。CC-TSC-Pd催化剂中起催化作用的是金属态的钯。     

连续反应技术在柑青醛生产中的应用研究

本文通过对多种不同类型连续反应装置的结构性能进行比较研究,探索连续反应装置结构类型及尺寸参数与反应产物选择性之间的关系,最终设计出一套理想的柑青醛连续生产工艺(反应装置),从而实现降低能耗50%、提高产物收率13%、质量达到国外产品同等水平、降低生产成本20%。     

Flame retardancy mechanisms of triphenyl phosphate,resorcinol bis(diphenyl phosphate) and bisphenol A bis(diphenyl phosphate) in polycarbonate/acrylonitrile–butadiene–styrene blends

The flame retardancy mechanisms of three aryl phosphates, triphenyl phosphate (TPP), resorcinol bis(diphenyl phosphate) (RDP) and bisphenol A bis(diphenyl phosphate) (BDP), in a polycarbonate/acrylonitrile–butadiene–styrene (PC/ABS) blend are investigated and compared. Further, the influence of polytetrafluorethylene (PTFE) on viscosity and thermal decomposition is discussed in the systems PC/ABS and PC/ABS + BDP. Mechanisms are proposed based on the results of various methods. Thermogravimetric analysis, Fourier transform infrared spectroscopy and kinetics are used to study the pyrolysis. The fire behaviour is studied by means of cone calorimeter measurements at different heat fluxes and the flammability is specified by limiting oxygen index (LOI) and UL 94. Rheology measurements are used to illuminate the changed dripping behaviour due to PTFE. TPP shows only a gas phase action. RDP shows mainly a gas phase action and some condensed phase action. BDP shows a crucial condensed phase action in addition to a gas phase action. TPP and RDP are somewhat superior in terms of flammability (LOI), whereas BDP shows superior performance in forced flaming combustion (cone calorimeter). Synergistic effects between PTFE and BDP are found. Copyright © 2007 Society of Chemical Industry     

月桂醛和琥珀酸酐接枝改性天然胶原所得产物的表面活性

以月桂醛与琥珀酸酐接枝改性具有三股螺旋结构的天然胶原,得到了一种保留了天然胶原结构的生物表面活性剂(胶原基生物表面活性剂,简称BCB)。研究了BCB的基本表面活性,结果表明,BCB具有较好的泡沫膨胀和泡沫稳定性,其乳化活性(284.08 m2/g)与天然胶原(32.23 m2/g)相比有显著的提高,乳化稳定性和吸油能力也有所提升。BCB的润湿能力随着其浓度的增加而提高,表面张力随存放时间的延长而降低,在质量浓度为5.0×10-3g/L时,表面张力在3 000 s时达到平衡,为52.58 m N/m。研究表明,BCB和天然胶原的乳液类型均为O/W型。     

芳香醛、苯乙酮和对硝基苯胺一锅法合成Mannich碱

在浓盐酸做催化剂的条件下,芳香醛、苯乙酮和对硝基苯胺能够发生Mannich反应,经过提纯得到相应的Mannich碱。用红外光谱对产物的结构进行表征,并研究浓盐酸的使用量、反应温度、反应时间等条件对产率的影响。实验发现在3滴浓盐酸催化下,控温在15~20℃,反应20 h,产率可达60%左右。     

Expeditious Synthesis of Functionalized 1‐Arylcyclooctadienes via Palladium‐Catalyzed Lithium Cross‐Coupling

The palladium‐catalyzed direct cross‐coupling of aryl bromides and (1Z,5Z)‐cycloocta‐1,5‐dien‐1‐yllithium is described as an important method to synthesize 1‐arylcyclooctadienes. The use of a well‐established Pd₂dba₃/XPhos catalytic system affords the desired new compounds in good to excellent yields; the reaction proceeds at room temperature with both high efficiency and selectivity. Finally we found the best conditions to combine a suitable lithium‐halogen exchange with a cross‐coupling reaction.

     

2-异丙基-5-甲基-2-己烯醛的合成与表征

以异戊醛为原料,在回流加热条件下进行羟醛缩合反应合成了2-异丙基-5-甲基-2-己烯醛。考察了催化剂种类和用量、相转移催化剂用量和反应时间等关键因素对反应的影响。实验结果表明,氢氧化钠作催化剂,其用量为异戊醛质量的3.0%,四丁基溴化铵作相转移催化剂,其用量为异戊醛质量的1.0%,反应3 h时,产物收率为83.3%。产品用红外光谱以及1H和13C核磁共振谱进行表征。     

邻香兰素乙二醇缩醛的合成

讨论了影响邻香兰素乙二醇缩醛的合成工艺影响因素。利用单因素实验方法,分别研究了反应时间,溶剂用量,乙二醇用量对邻香兰素乙二醇缩醛的收率的影响。以邻香兰素乙二醇缩醛的收率为指标,结果表明较优的合成条件是:反应时间为4 h,溶剂用量为50 mL,乙二醇用量为20 mL。为邻香兰素的进一步开发和利用提供了参考,同时也为邻香兰素的醛基保护提供了一种可以参考的途径。