荧光增白剂4,4′-二(4-磺酸钠苯乙烯基)二苯甲酮的合成

用Heck反应合成了4,4′-二(4-磺酸钠苯乙烯基)二苯甲酮.对Heck反应条件进行了改进,使用壳聚糖负载钯为催化剂并考察了催化剂的回收再利用情况.通过研究影响该反应的各种因素,如反应时间、反应温度、原料配比等,优化了实验条件,得到了较好的结果.     

Study on the reaction kinetics between PBT and epoxy by a novel rheological method

In the present study, the reaction kinetics of polybutylene terephthalate (PBT) and epoxy system was studied by a novel rheological method. The reaction process was determined by rheological test and the results showed that there were three stages in the reaction between PBT and epoxy, which were reaction-controlling stage (stage I), reaction-stagnation stage (stage II) and diffusion-controlling stage (stage III). In addition, the stage I was selected to study the reaction kinetics by the rheological method. The results showed that the reaction between PBT and epoxy could be classified as a pseudo-first-order reaction due to the excessive amount of epoxy group. Furthermore, the reaction apparent activation energy of the stage I determined by the rheological method was 143 kJ/mol. To confirm these results, the reaction kinetics was also evaluated by the endgroup determination method, and the results showed that the reaction could also be classified as a pseudo-first-order reaction. Moreover, the apparent activation energy of the reaction was 116 kJ/mol, which was similar to that of the value obtained by the rheological method.     

维生素K3电化学反应机理的紫外光谱电化学研究

用薄层池循环伏安法和现场薄层池紫外光谱电化学法研究了维生素Ｋ３（ＶＫ３）在铂电极上的电化学反应机理。薄层池循环伏安实验结果表明：ＶＫ３的电化学反应为二步１ｅ准可逆过程，现场薄层池紫外光谱电化学的实验结果和Ｎｅｒｎｓｔ图解分析表明：电解还原反应的最后产物为２－甲基－１，４－萘酚。该反应偶合有前行化学反应；还原产物经电解氧化的产物为２－甲基－１，４－萘酚。该反应偶合有前行化学反应；还原产物经电解氧化的     

Study of the reaction between boron trifluoride methanol complex and sodium methoxide

The reaction between boron trifluoride methanol complex and sodium methoxide in methanol solution was investigated using conductivity as the reaction indicator. The reaction conditions were examined and a mechanism of this reaction was proposed. Moreover, proper reaction conditions were proposed for boric acid preparation using this reaction.     

Optimization of reaction conditions for REM resin-bound quaternization reactions

A study into the effect of reaction variables on the quaternization of REM resin-bound tertiary amines was undertaken. The influence of resin matrix, solvent, reaction time, temperature, and amount of quaternization agent on the outcome of reaction was evaluated by reaction monitoring using (19)F NMR. The highest yields of tertiary amine products were seen when DMSO was used as reaction solvent in conjunction with a reaction time of 18 h at room temperature. The use of heating for extended reaction times tended to depress yields, indicating product cleavage during quaternization. Quaternization on PS-DVB resin was found to be more robust than reaction on PS-PEG matrices where yields were generally considerably lower than the observed conversions. DMSO was the most efficient reaction solvent for both resins despite poor swelling of the quaternization starting material.     

苯并噻唑-2-甲醛合成方法的改进

以邻氨基苯硫酚为原料,先与羟基乙酸反应合成2-羟甲基苯并噻唑,然后通过氧化反应生成苯并噻唑-2-甲醛。对比了几种氧化剂的效果,发现二氧化锰氧化的效果最好。优化的反应条件为,2-羟甲基苯并噻唑与二氧化锰的摩尔比为1∶8,回流反应8h,产率可达90.2%。该方法适合苯并噻唑-2-甲醛及其衍生物的大规模生产。     

Direct partial oxidation of methane to methanol： Reaction zones and role of catalyst location

Direct partial oxidation of methane to methanol was investigated in a specially designed reactor. Methanol yield of about 7%-8% was obtained in gas phase partial oxidation. It was proposed that the reactor could be divided into three reaction zones, namely pre-reaction zone, fierce reaction zone, and post-reaction zone, when the temperature was high enough to initiate a reaction. The oxidation of methane proceeded and was completed mostly in the fierce reaction zone. When the reactant mixture entered the post-reaction zone, only a small amount of produced methanol would bring about secondary reactions, because molecular oxygen had been exhausted in the fierce reaction zone. A catalyst, if necessary, should be placed either in the pre-reaction zone, to initiate a partial oxidation reaction at a lower temperature, or in the fierce reaction zone to control the homogeneous free radical reaction.     

低热固相反应的反应机理研究(Ⅰ)——冷融熔机理和冷溶熔机理的模型

本文提出了低热固相反应的冷融熔机理和冷溶熔机理,其中冷融熔机理主要针对于不含结晶水的反应体系,冷溶熔机理主要针对于含结晶水的反应体系,并对低热固相反应动力学提出冷融熔/冷溶熔、扩散、反应、成核、生长的五步机理。两种机理都避开了分子在固相晶格中的扩散,从而对低热固相反应的扩散问题进行了有效的解释,并给出了低热固相反应的热力学和动力学判据。     

SnO2/CeO2表面反应速率方程和分子反应几率

The principle and experimental law of testing sets to test reaction temperature change were introduced. Using “powder sputtering plane thin-film SnO2/CeO2 alcohol sensor”, the reaction temperature change was tested and the law of versus gas concentration was given by the inserting method. The rate equation of surface reaction was deduced and reaction probability of surface molecule was calculated. The general reaction rate equation includes two kinds of experiential formula—hyperbolic and power function formula and the concept of molecule reaction probability is minor, which in general is 10-3-10-5.     

The electrochemical reaction mechanism of selenocystine on selenium-gold film modified glassy carbon electrode

A simple and selective voltammetric method based on selenium-gold film modified glassy carbon electrode has been developed for investigating electrochemical reaction mechanism of selenocystine. With N₂ saturated, redox reactions between selenocystine (SeC) and selenocysteine (SeCys) were judged to be two simple electron-transfer processes. With air saturated, the reduction reaction was diagnosed to be EC catalytic reaction (the chemical oxidation reaction of the SeCys by O₂ (C) following the electron-transfer reaction (E)) and oxidation reaction is a simple electron-transfer process. With pure O₂ saturated, only reduction peak was observed and the reaction was judged to be EC catalytic reaction. The electron-transfer numbers of redox reaction were calculated to be 2 by chronocoulometry and rotating disk electrode.     

Effect of phase transfer chemistry, segmented fluid flow, and sonication on the synthesis of cinnamic esters

Wittig reaction under Phase Transfer conditions was performed in a flow reaction system. Different bases, aldehydes, phosphonium salts, and flow reaction parameters were investigated, in absence of a phase transfert catalyst. An improvement of the reaction outcome (yield and reaction time) was achieved through the immersion of the reactor into an ultrasound bath.     

低温常压氧气液相氧化邻硝基甲苯的表观动力学研究

文章讨论了低温常压条件下氧气液相氧化邻硝基甲苯的表观动力学。在确定了邻硝基苯甲醛和邻硝基苯甲酸为主要产物的基础上，建立了连串反应模型，根据不同温度下的实验数据，确立了首步一级，第二步二分之一级的反应级数，进而求得了两步反应的速率参数k1、k2，并将实验数据与理论计算值相比较，表明在较低温度(0℃以下)下，拟合的级数与使用符合较好。     

三苯基环戊二烯扩环反应研究

研究在高氯酸银作用下,三苯基环戊二烯扩环氧化生成三苯基取代吡喃盐的反应,并初步探讨了反应机理     

Efficient C-C double-bond formation reaction via a new synthetic strategy: a self-sorting tandem reaction

[reaction: see text] A novel and efficient carbon-carbon double-bond formation reaction via coupling of aryl or heteroaryl methyl ketones has been developed. A dimethyl sulfoxide-iodine-CuO system was proven to be efficient for this reaction and afforded the expected products in good yields. A new synthetic strategy, a self-sorting tandem reaction, was involved in this type of reaction and was presented for the first time.     

纳米TiO_2光催化芳香醛的缩醛反应研究

本文以纳米TiO2为催化剂,UV-LED（=365 nm）为紫外光源,在自制的恒温石英玻璃光催化反应器中成功实现了芳香醛的非均相光催化缩醛反应.以乙醇等作为溶剂和反应物,快速高效和高选择性地合成了苯甲醛二乙基缩醛（BDA）.在光强为0.6 mw/cm2,苯甲醛初始浓度为0.05 mol/L,催化剂TiO2（P25）用量为5.0 g/L,反应时间为15 min的条件下,苯甲醛二乙缩醛的产率可达99.86%.研究表明,氧气的存在是顺利发生光催化缩醛反应的重要条件.反应液pH值、醇溶剂种类及苯环对位取代基等因素都会对光催化缩醛反应速率和产率产生影响.pH值及醇溶剂的pKa越小,缩醛反应速率越快.苯环上对位取代基会抑制缩醛反应的进行,其中供电子取代基相对吸电子取代基更有利于缩醛反应进行.结合实验,提出了光催化缩醛反应的机理.     

Total synthesis of leustroducsin B

Leustroducsin B was synthesized via a convergent route based on division of the leustroducsin molecule into three segments A, B, and C. Two coupling reactions (Julia coupling reaction and Nozaki-Hiyama-Kishi (NHK) reaction) were employed for coupling of segments A and B: segment A1 for the Julia coupling reaction was prepared by a combination of Sharpless asymmetric epoxidation and an epoxide-cleavage reaction with an organoaluminum reagent, while segment A2 for the NHK reaction was synthesized from optically active alcohol that had previously been prepared by lipase-catalyzed kinetic resolution. Segment B, whose structure was modified with some functional groups, was synthesized from (R)-malic acid by a combination of Wittig reaction and Sharpless asymmetric dihydroxylation, and segment C, containing a cyclohexane moiety, was prepared by asymmetric Diels-Alder reaction. Segment B was first coupled with segment A1 via the Julia coupling reaction, but the yield was low due to unexpected epimerization. The NHK reaction of segment A2 proceeded to give the coupling product in good yield. This product was coupled with segment C via Wittig and Stille coupling reactions, and finally, phosphorylation was carried out by partial hydrolysis of a cyclic phosphate to give leustroducsin B.     

双核水杨醛亚胺铁系催化剂的合成及对乙烯齐聚催化性能的研究

以1.0代(1.0G)树枝状大分子、水杨醛和FeCl_2·4H_2O为原料,依次经过希夫碱反应和络合反应合成了一种双核水杨醛亚胺铁系催化剂。FT-IR、1 H NMR、UV和MS证实合成产物的结构与理论结构相符。以甲基铝氧烷(MAO)为助催化剂,考察了溶剂种类、反应温度、反应压力、Al/Fe摩尔比及金属活性中心种类对催化体系催化乙烯齐聚性能的影响。结果表明,当以甲苯为溶剂,聚合时间为30min,反应温度为15℃、反应压力为0.5MPa、Al/Fe摩尔比为1000时,该双核水杨醛亚胺铁系催化剂的活性可达1.14×10~5g/(mol Fe·h),齐聚产物中C_4及C_6烯烃含量高达90%以上。     

氯固相合成Ti-ZSM-5催化苯乙烯环氧化对映选择性 的研究

用TiCl~4气固相同晶取代法制得的Ti-ZSM-5作催化剂。研究了以H~2O~2为氧化剂氧化苯乙烯生成环氧苯乙烷的对映选择性,发现生成的环氧苯乙烷主要以R构型为主。考察了反应时间,反应温度,催化剂Ti-ZSM-5以及氧化剂[w(H~2O~2)=30%]的用量等反应条件对苯乙烯环氧化反应对映性的影响。结果表明,反应温度是影响环氧化反应对映选择性的重要因素,降低反应温度有利于提高对映选择性(ee),当反应温度≤40℃时,ee值可达100%;而反应时间,催化剂及氧化剂[w(H~2O~2)=30%]用量对环氧化反应的对映选择性几乎没有影响。     

Stereospecific deoxydichlorocyclopropanation of expoxides by dichlorocarbene generated in an emulsifying system

The reaction of epoxides with dichlorocarbene generated in an emulsifying system was investigated. The products were the corresponding dichlorocyclopropane derivatives. The reaction of cis- and trans-β-methylstyrene oxides showed the reaction was completely stereospecific. Styrene oxide gave the corresponding dichlorocyclopropane and styrene, where the concentration of the latter was kept in the nearly stationary state during the reaction. Further the competitive reaction of α- and β-methylstyrene oxide showed that introduction of an additional Me group at the α-position accelerated the reaction only 12 times. From these observations the reaction was concluded to involve the two step process, namely, the deoxygenation process and dichlorocyclopropanation process, both of which were stereospecific and practically concerted.     

Novel fragmentation reaction of correolide

[reaction: see text] Pentacyclic triterpenoid natural product correolide (1) was converted to ketone 2 via ozonolysis. An unusual fragmentation reaction of ketone 2 with LiCl was discovered. This reaction is general among several similar substrates examined and appears to be specific for the correolide-type E-ring structure (ketone). A mechanism involving a retroaldol reaction, a nucleophilic opening of the epoxide, and a subsequent acetoxy elimination reaction was proposed.