假紫罗兰酮环化工艺条件探讨

讨论了假紫罗兰酮酸化环合制备紫罗兰酮不同工艺条件对产品收率和组成的影响,结合有关文献重点探讨了作为维生素A工业合成原料的β-紫罗兰酮合成工艺条件的改进和优化,尤其是硫酸有机稀释剂(溶剂)的应用。     

Synthesis and reactivity of Mannich-derived polyoxyethylene amines as epoxy curing agents

The facile Mannich reaction of phenol, formaldehyde, and polyoxyalkylene polyamines at various molar ratios afforded a family of polyetheramines containing functionalities of phenol, primary amines, secondary amines, and polyoxyethylene or polyoxypropylene block copolymers in the same molecule. The synthesis can be generalized by using various polyoxyethylene or polyoxypropylene diamines (and triamines) of molecular weights ranging from 104 to 430 to prepare a family of Mannich amines, with exception of certain gel products such as phenol/formaldehyde/bis(aminoethyl)ether adduct at 1 : 3 : 3 molar ratio. The series of Mannich amines were evaluated for their epoxy curing reactivities by comparing their gel time and drying time. The Mannich amines prepared from polyoxyethylene amines exhibited higher reactivities than those of polyoxypropylene amine derivatives. The trend of their relative reactivities is explained by the molecular size, the multiplicity of amines in the molecule, and the steric hindrance of amine structure. The physical properties of cured epoxy materials, such as impact, tensile, flexural strength, and hardness properties were also measured and correlated with the amine molecular weight, crosslinking density, and the presence of phenol group. The structure–property relationship is discussed. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 2339–2346, 1997     

Sorption and diffusion of water,salt water,and concrete pore solution in composite matrices

In recent years, the use of fiber‐reinforced polymer composites in civil infrastructure has been promoted as a solution to the deterioration of bridges, buildings, and other structures composed of traditional materials, such as steel, concrete, and wood. Any application of a polymer composite in an outdoor environment invariably involves exposure to moisture. There is also potential for exposure to saline conditions in waterfront or offshore structures, and alkaline environments, as would be encountered by a reinforcing bar in a cementitious material. This study characterizes the sorption and transport of distilled water, salt solution, and a simulated concrete pore solution in free films of vinyl ester, isophthalic polyester (isopolyester) and epoxy resins, all commercially important materials for use in structural composites. Diffusion of all three liquids in each of the three materials was observed to follow a Fickian process. Mass loss was observed for the isopolyester in salt water and concrete pore solution at 60°C, suggesting hydrolysis that was accelerated by the high temperature exposure. Both the rate of uptake, as well as the equilibrium uptake, were greater at 60°C, compared with ambient conditions. Diffusion coefficients calculated from the mass uptake data revealed that, although the epoxy resin had the highest equilibrium uptake, it had the lowest diffusion coefficient. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 483–492, 1999     

Synthesis and characterization of vinyl ester networks containing phthalonitrile moieties

A new styrenic monomer, 4-vinylphenoxyphthalonitrile, was synthesized by nucleophilic aromatic substitution of 4-vinylphenolate onto 4-nitrophthalonitrile. The new monomer was reacted with dimethacrylate-styrene resins (so-called vinyl esters) via free radical copolymerization at 90, then 120 °C with benzoyl peroxide as the initiator to form networks. The networks were further post-cured at 220, 240, or 260 °C for 4 h to convert the last portion of the methacrylates, and to partially cross-link the pendent phthalonitrile groups. A dimethacrylate-styrene network containing 30 wt% of the phthalonitrile-functional monomer exhibited a 70% reduction in peak heat release rate by cone calorimetry measured at an incident heat flux of 50 kW m⁻² relative to control vinyl ester networks. This still remains somewhat higher than peak heat release rates exhibited by brominated vinyl ester networks, but the CO/CO₂ ratio in the smoke is much lower for these non-halogenated materials.     

磷酸酯类表面活性剂的现状及发展

论述了磷酸酯类表面活性剂的分类、基本性能、特性及应用,介绍了磷酸酯类表面活性剂的发展状况。     

不同载体钯催化剂的结构表征及其在笼形叔胺脱N-苄基上的应用

以γ Al2O3、木质活性炭、煤质活性炭为载体,以氯化钯为前体制备了Pd(OH)2/Al2O3、Pd(OH)2/C催化剂,并用X射线衍射、透射电镜和X射线光电子能谱等技术对这些催化剂进行了结构表征。以六苄基六氮杂异伍兹烷(HBIW)的脱苄反应为例,研究了不同载体Pd(OH)2催化剂对笼形叔胺N 苄基脱苄反应的活性,分析了影响催化剂活性的各种因素。实验结果表明,当催化剂用量为HBIW质量的0 2%(以Pd计)时,氢解产品四乙酰基二苄基六氮杂异伍兹烷(TADBIW)的收率可达88%,其中以煤质活性炭为载体的催化剂已用于HBIW氢解脱苄的20kg级放大实验,TADBIW产品收率为82%。     

TiOSO4催化合成脂肪族的10种羧酸酯及其催化活性表征

用硫酸钛经高温焙烧制得一类新型固体酸催化剂TiOSO4,该催化剂通过X射线衍射仪谱图和吸附吡啶的红外光谱谱图解析：TiOSO4表面存在明显的Broensted酸性位,400、450、500℃焙烧得到的固体酸在催化合成脂肪族的10种羧酸酯中具有很好的催化活性,短时间内,转化率可达到96％以上,并对此确定了最优化工艺条件。其酯化反应结束后后处理工艺简单,催化剂容易回收,不需再生可重复使用多次。     

羧基化碳纳米管的酯化与酰氯化修饰研究

采用稀硝酸和浓硝酸、浓硝酸和浓硫酸两种方法在碳纳米管上引入羧酸基团，利用羧酸基团修饰的碳纳米管分别与溴代正丁烷和氯化亚砜反应，在碳纳米管上引入了酯基和酰氯基团，采用红外光谱对所引入的基团进行了表征验证，为碳纳米管的进一步功能化和应用提供了实验方法。     

自流平型环氧地坪涂料的研制

主要研究了自流平型环氧地坪涂料固化剂对涂膜性能的影响。详细研究了多元脂肪胺的类型、混合多元脂肪胺的混合工艺、助剂、环氧树脂、反应时间等对固化剂的粘度及涂膜的光泽度等的影响。所制得固化剂的粘度为 170 0mPa·s,涂膜硬度为 71% ,光泽度为 97% ,耐腐蚀性能好。     

电喷雾质谱法示踪钨回收过程离子的转化路径

将环隙式离心萃取器(ACCs)与电喷雾飞行时间质谱(ESI-TOF-MS)相结合,在线监测了回收过程中的钨萃取行为(宏观)和钨形态的转化路径(微观),发现宏观萃取反应和微观离子形态转化同时发生并相互补充。伯胺N1923萃取钨在144 s内即可达到萃取平衡,萃取率高达98%以上,同时,酸钨比n(H)/n(W)是一个关键变量,当酸钨比n(H)/n(W)=2.4时,全流程钨回收率超过93%。最后,得到了基于钨形态监测的萃取机理,同时,减少原料液中W1含量,增加W10含量,可有效提高钨回收效率。