三甲基酰氧基硅烷与环氧氯丙烷的开环反应

Ring cleavage reaction between trimethylacyloxysilances and epichlorohydrin using 5-t-buty 1-2-furanatochromium (IIIe n(TBF)3Cr) as catalyst was studied in detail and the products, various esters of β-trimethylsiloxy-y-chloropropanol, were obtained. Relative reaction rates between various acyloxysilances and epichlorophydrin were compared by determining the half-lives of the acyloxysilances. The direction of ring cleavage was examined with IR, ^1H NMR, ^1^3C NMR and HPLC and comparable to that reported in literature. Toxicity of these products was determined.     

乙酰氧基硅烷和1,2-环氧化合物的开环反应

本文以5-叔丁基呋喃甲酸铬(Ⅲ)和三氯化铝作催化剂,使乙酰氧基硅烷和环氧化物,在均相或非均相条件下反应,得到了相应的开环加成产物--取代硅氧丙基乙酸酯。实验结果表明,在本文的两种实验条件下,使用5-叔丁基呋喃甲酸铬(Ⅲ)作催化剂比用三氯化铝更为有效。     

分子筛催化下环氧氯丙烷开环反应的溶剂效应

环氧化合物与羧酸的开环加成酯化是有机化学中一类重要反应,开环形成的羧酸β-羟基酯有着十分广泛的用途。这类反应的进行通常需要高活性的催化剂,我们曾将Fe(Ⅲ)改性的ZSM-5分子筛应用于羧酸β-羟基酯的合成。本文用Fe-ZSM-5分子筛为催化剂,以环氧氯丙烷与丙酸反应作为模型,研究了取代苯为溶剂时对反应速率的影响,发现反应的速率     

三甲基酰氧基硅烧与环氧氯丙烷的开环反应

本文详细地研究了以5-叔丁基呋喃甲酸铬为催化剂,三甲基酰氧基硅烷与环氧氯丙烷的开环反应。用半衰期(t_(1/2))法比较了各种酰氧基硅烷与环氧氯丙烷的反应速率。制备了一系列羧酸β-三甲硅氧基γ-氯丙酯类衍生物。通过对产物的HPLC,IR,~1HNMR和~(13)CNMR等分析,初步探讨了环氧氯丙烷的开环方向。测定了部分产物的半致死量(LD_(50)),首次发现这类产品具有生物活性。     

酰氧基硅烷和环氧化合物的开环反应动力学及其机理

酰氧基硅烧和环氧化合物的开环反应可用于环氧树脂的改性.但对该反应的研究不多.我们发现5-叔丁基呋喃甲酸铬是酰氧基硅烷和环氧化合物开环反应的较好催化剂,认为有必要研究这一催化反应的动力学和反应机理.我们以三甲基乙酰氧基硅烷和环氧氯丙烷为模型化合物,研究了在5-叔丁基呋喃甲酸铬的存在下,以甲苯为溶剂,酰     

热动力学的研究(Ⅵ)——环氧氯丙烷开环反应的热动力学

本文在前文所建立的热动力学方程和无量纲参数研究法的基础上,对较为复杂的环氧氯丙烷开环反应的研究,扩大了热动力学的研究范围。早在1929年,Bronsted等采用特殊的实验方法,对环氧乙烷及类似化合物进行了较为全面的研究,并测定了在盐酸溶液中,环氧乙烷等化合物可能发生的各种开环反应的速度常数。本文测定了环氧氯丙烷与碘化钾在磷酸盐缓冲液中的开环反应     

苯并咪唑开环反应研究

本课题组曾首次报道过咪唑啉的还原开环反应[1],2-烷基-2-咪唑啉在硼氢化钠作用下生成开环产物--乙二胺衍生物.通过对这一新反应的研究,提出了通过咪唑啉制备N-取代乙二胺、N,N-二取代乙二胺、4-取代二亚乙基三胺等乙二胺衍生物简便的新合成方法.在此基础上,我们对苯并咪唑衍生物进行了类似的反应研究,希望通过其开环反应制备N-取代邻苯二胺、N,N'-多取代邻苯二胺衍生物.     

钯催化C-H乙酰氧基化反应

Pd催化的C—H官能化反应是目前有机合成方法学的一个重要研究热点.毫无疑问,这种温和又有选择性地转化方式广泛运用于化学各个领域.钯催化反应在近十年内得到了很大的发展,但是对于有机化学家来说仍然是一个挑战.综述了近十年来关于在C(sp2)—H和C(sp3)—H乙酰氧基化反应的研究进展及其应用,并提出了今后的研究重点和发展趋势.     

一种多取代硝基环丙烷的开环反应研究

以一种多取代硝基环丙烷为底物,研究其在不同条件下的开环反应.以苄胺为亲核试剂时,底物发生开环生成烯胺化合物,对此反应机理进行了分析.研究了底物的还原开环反应：1）在Pd/C的催化氢化下,底物发生开环并消除硝基,得到烷基取代丙二酸二甲酯衍生物;2）在浓盐酸存在下用锌粉还原底物,得到五元环内酰胺.     

呋喃环参与的Diels-Alder反应及其应用

呋喃环在作为Diels-Alder反应的二烯组份中得到了广泛的研究.本文就呋喃环参与的分子间和分子内D-A反应及其应用作一综述.     

磺胺胍与四氯苯醌的荷移反应

研究了磺胺胍与四氯苯醌之间的荷移反应。在碳酸钠 碳酸氢钠缓冲溶液中磺胺胍与四氯苯醌能形成淡紫色荷移配合物。配合物的最大吸收波长为540nm,表观摩尔吸光系数为2.45×103L·mol-1·cm-1,线性范围为0～50mg·L-1,其配合比为1∶2。应用拟定的方法测定磺胺胍制剂的含量,平均回收率为99.5%,RSD为0.38%(n=6),可用于实际样品的分析。     

咔唑与氯代烷烃的光化反应

本文研究了咔唑与氯代烷烃在光照下的相互作用,并用荧光发射光谱、激发光谱、咔唑的氯代烷烃溶液光照后与二甲基黄溶液混合发生的颜色变化,证明了光照下咔唑与氯代烷烃产生了化学反应,同时通过荧光猝灭和燐光实验证实了该反应是通过激基复合物进行的,简短地讨论了反应初期的反应机理。     

THE REACTION BETWEEN SUPEROXIDE ANION AND HYDROGEN PEROXIDE

Abstract— In order to obtain a better understanding of the kinetics of the Haber-Weiss reaction

often proposed as a source of OH radicals, we have measured the decomposition rate of H₂O₂ in aqueous solutions by y rays and for different pH values. This decomposition proceeds by a chain reaction involving the preceding one as the propagating step.
The rate constant found is to be
     

THE CHLOROPHYLL-SENSITIZED REACTION BETWEEN BENZOQUINONE AND ETHANOL*

The electron-transfer reaction between triplet excited chlorophyll and quinones has been extensively studied as a model of the primary reaction in photosystem II. There has also been reported a minor reaction in which the chlorophyll cation radical ostensibly oxidizes the alcohol solvent or even water, leading to a gradual net reduction of quinone, but the exact mechanism and even the existence of this reaction has been uncertain. We have examined the consequences of prolonged irradation of ethyl chlorophyllide and benzoquinone in acidulated ethanol, and find a chlorophyllide-sensitized reaction which is not analogous to the better-known autosensitized reduction of quinones in blue or UV light. In the chlorophyllide-sensitized reaction, benzoquinone is apparently converted to ethoxy-substituted quinones and quinols, and polymeric material. Ethyl chlorophyllide (or chlorophyll) is simultaneously oxidized to more polar products which themselves continue to photosensitize the reaction of quinones. The production of acetaldehyde could not be demonstrated in the sensitized reaction. Chlorophyllide-sensitized reaction of (l-hydroxyethyl)benzoquinone, ethoxybenzoquinone and 2.5-diethoxybenzo-quinone were examined for additional information. A reaction sequence, tentatively proposed to accommodate the known facts, starts with oxidative attack by quinone on an oxidized chlorophyllide radical formed by loss of a hydroxyl proton from alcohol bound as a ligand to Mg²⁺. It is not likely that this reaction is closely related to events at the oxidizing side of photosystem II.     

苯骈咪唑-N-Mannich碱与苯乙酮的交换反应

Mannich反应是在有机合成中广泛采用的反应,是甲醛与胺及含有活性氢的分子(如甲基酮等)发生缩合反应,是制备β-胺基酮类的方便方法.但一般认为芳香胺不能参加这个反应,因此,可先制成脂肪胺的Mannich碱,然后用芳香胺交换来制备β-芳胺基酮^[1-5].     

MECHANISM OF THE REACTION BETWEEN LUMINOL AND MOLECULAR OXYGEN

Abstract— The oxidation of luminol by molecular oxygen in dimethylsulfoxide was studied by following the intensity of emitted light. The results indicate that the reaction takes place through reversible formation of an oxygen-containing intermediate. The stability constant of this compound has been determined in IDMSO: ethanol (4:1) mixed solvent. The effects of different parameters were investigated and a quantitative relationship established between the intensity of emitted light and the concentrations of the reactants.
New methods for determining (oxygen concentrations in gases and for demonstrating cold light emission are suggested.     

端羟基丁腈与二异氰酸酯反应动力学研究

本文对端羟基液体丁二烯/丙烯腈共聚物与二异氰酸酯的反应动力学进行了研究。通过化学分析方法测定反应速率,确定该反应为二级反应,反应活化能E_a =6.44kcal/mol。同时研究了一些因素对反应速率的影响。结果表明,共聚物中丙烯腈含量愈高,反应速度愈快,即氰基对反应有自催化作用。二月桂酸二丁基锡是反应的有效催化剂。不同异氰酸酯与端羟基液体丁二烯/丙烯腈共聚物的反应活性的顺序为4,4′-二苯基甲烷二异氰酸酯、2,4-甲苯二异氰酸醋、2,4/2,6-甲苯二异氰酸酯、1,6-六次甲基二异氰酸酯。