ω,ω-二溴-对苯基苯乙酮的合成研究

以对苯基苯乙酮和溴素为原料、冰醋酸为反应介质,合成了ω,ω-二溴-对苯基苯乙酮。考察了原料配比、反应温度、反应时间等因素对反应收率的影响。优化合成条件:n(溴素)∶n(对苯基苯乙酮)=2.2∶1,反应温度45～50℃,反应时间2.5h。产品总收率89.7%,熔点114～116℃。产物结构经红外光谱、核磁波谱表征。     

2,6-二溴苯胺的合成工艺改进

对 2 ,6 二溴苯胺的生产工艺路线进行了比较 ,提出以对氨基苯磺酸为起始原料 ,经与氢氧化钡成盐 ,再经溴化 ,水解 ,可得 2 ,6 二溴苯胺。考察了反应温度和反应时间对 2 ,6 二溴苯胺收率的影响 ,最佳反应温度为 16 5℃～ 170℃ ,反应时间为 3h。在此条件下 ,2 ,6 二溴苯胺总收率为 72 % ,纯度 98.5 %以上。与传统工艺相比 ,2 ,6 二溴苯胺合成成本可大幅下降     

2-(4-溴甲基苯基)丙酸合成

以甲苯为原料,经Friedel-Crafts、Willgerodt-Kindler-水解"一锅法",单甲基化和溴代反应合成了洛索洛芬的关键中间体2-(4-溴甲基苯基)丙酸。结果表明:超声波能促进Friedel-Crafts、Willgerodt-Kindler水解反应,使用复合相转移催化剂可得高收率的单基化产物。该合成路线操作简便、原料易得,总收率55.1%。     

异丁烯-对甲基苯乙烯无规共聚物可见光溴化反应的选择性

使用气相色谱仪对几种不同纯度的正己烷和环己烷进行了组分分析,并对包括2-甲基戊烷、3-甲基戊烷和甲基环戊烷在内的正己烷的主要支链型同分异构体成分,以及异丁烯-对甲基苯乙烯无规共聚物中对甲基苯乙烯结构单元的模型分子对二甲苯和对二异丙苯在波长为365～840 nm的可见光照射下的光溴化反应进行了对比,筛选出可以有效避免溶剂发生光溴化副反应并提高目标光溴化反应选择性的可见光波长。此外,将异丁烯-对甲基苯乙烯无规共聚物在质量分数为85.740 0%～99.960 0%的溶剂正己烷和环己烷中的光溴化反应的选择性进行了对比,并考察了除酸剂碳酸氢钠和反应温度对异丁烯-对甲基苯乙烯无规共聚物在正己烷中光溴化反应的影响。结果表明,波长为595 nm和630 nm的可见光可作为异丁烯-对甲基苯乙烯无规共聚物光溴化反应的光源,在质量分数为85%的工业正己烷中即可实现良好的光溴化反应,溴的有效利用率可达到70%～80%;碳酸氢钠作为酸蚀剂可以有效抑制异丁烯-对甲基苯乙烯无规共聚物的凝胶化反应。此外,反应温度对光溴化反应有一定影响,当反应温度从5 ℃降至-20 ℃时,溴化反应速率降低了58.87%。     

2‐Aminopyridines as an α‐Bromination Shuttle in a Transition Metal‐Free One‐Pot Synthesis of Imidazo[1,2‐a]pyridines

A wide range of imidazo[1,2‐a]pyridines are accessible from cheap and readily available 2‐aminopyridines and 1,3‐dicarbonyl compounds using a unique CBrCl₃/2‐aminopyridine system for bromination at the α‐carbon. 2‐Aminopyridine is not only the substrate but also acts as a bromination shuttle, transferring the bromine atom from CBrCl₃ to the α‐carbon of the 1,3‐dicarbonyl. The reaction mechanism involves a series of reversible steps, including an addition reaction with cyclic transition state, to form a bromo‐hemiaminal intermediate. Isolated yields of up to 97% were obtained under mild conditions and at short reaction times in this transition metal‐free, one‐pot synthesis.

     

薄层色谱法研究乙酰丙酸乙酯溴化反应

用薄层色谱法监测溴素溴化乙酰丙酸乙酯生成3-溴乙酰丙酸乙酯的反应过程,优化了反应条件,方法简单,快速,准确。     

Studies of the halogenation of dissolved organic material during the chlorination of saline cooling waters,the model compounds resorcinol diacetate and resorcinol dimethyl ether

Chlorination of seawater containing resorcinol diacetate or resorcinol dimethyl ether results primarily in the formation of brominated products. At low chlorine concentrations (cf. model compound), ring substitution products dominate whilst at higher chlorine levels ring cleavage occurs and trihalomethanes are produced. Electrophilic chlorination of the model compounds in seawater therefore appears to be slower than the formation of HOBr by oxidation of naturally occurring bromide. The influence of solution acidity on the nature and extent of halogenation is described and reaction mechanisms postulated.     

对溴苯酚的合成

以氯仿为溶剂直接溴化制备对溴苯酚，在工艺上减少了减压蒸馏步骤，避免了对溴苯酚在高温下发生岐化异构化反应，结果纯度达到99．7％以上，收率为91％。     

Fundamental studies of homogeneous cation exchange membranes from poly(2,6‐dimethyl‐1,4‐phenylene oxide): Membranes prepared by simultaneous aryl‐sulfonation and aryl‐bromination

Strong acid homogenous cation exchange membranes were obtained by simultaneously introducing sulfonic and bromine groups into poly(2,6‐dimethyl‐1,4‐phenylene oxide) (PPO). The ion‐exchange capacity (IEC), water content, transport number, diffusion coefficient, contact angle, and tensile strength of the obtained membranes were studied. The results show that the membrane intrinsic properties are largely dependent on the substitution of bromine: the IEC and water content decrease with bromine content, while the area resistance and permselectivity of the membranes increase with this trend. Therefore, by properly balancing them, a series of homogenous cation exchange membranes having good electrical properties and physical stability can be obtained to comply with different industrial electromembrane processes, such as diffusion dialysis, electrodialysis, electrodeionization, etc. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2238–2243, 2006