磺化酞菁在甲醇-水溶液中的二聚作用研究

研究了不同磺化度的酞菁在甲醇－水混合溶剂中的聚集行为，通过紫外－可见光谱测定，发现磺化度在１．０以上的时染料在稀溶液中主要单体和二聚体的形式存在，并可用简单的方法计算出聚集平衡常数和平衡时单体所占的百分化，得到磺化越低越易聚集的结论，有关激发态的实验表明，增加酞菁磺化度有助于提高表观荧光量子产率，但对荧光寿命影响较小。     

Cathodic Dimerization

The technical, electrochemical, and preparative aspects of cathodic dimerization, which leads to bifunctional compounds, are reviewed. With the hydrodimerization of acrylonitrile as an example, the effects of the reaction parameters and the mechanism are discussed in detail. In addition to the hydrodimerization of activated compounds, the coupling can also proceed via elimination of halide or via the discharge of cations. Processes of special preparative interest are those in which two different molecules are coupled, which can yield e.g. esters, alcohols, or ketones with cyano groups, as well as asymmetric diols. The reductive dimerizations of acrylonitrile, β-chloropropionitrile, acetone, acetylpyridine, nitrobenzene (→ benzidine), and pyridinium salts have already found industrial use.     

Dimerization of haplamine

Institute of the Chemistry of Plant Substances, Uzbek SSR Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 51–53, January–February, 1989.     

Dimerization of Acetylenic Amides

Summary.  Dimers of substituted acetylenic amides were obtained when triethylamine was used as refluxing solvent and acid acceptor instead of pyridine in the reaction of substituted acetylenic amides with triphosgene. Unsubstituted acetylenic amides resulted in the corresponding quinazolinone. Received October 22, 2001. Accepted (revised) November 22, 2001     

异丁烯二聚反应

由于甲基叔丁基醚(MTBE)对水源的污染,它作为汽油添加剂的应用受到环保限制,并对其生产和应用前景带来消极影响。MTBE经裂解、二聚和加氢生产异辛烷成为国外现有MTBE装置转产的主要途径。本文对异丁烯二聚催化剂、反应活性位、机理及动力学研究成果进行了综述,试图解释在异丁烯二聚时,加入的叔丁醇对二聚反应选择性提高的作用机理,为今后二聚反应的研究提供参考。     

Dimerization of 2-hydroxybenzindolequinones

It is shown that the decarboxylation of 2-hydroxybenz[f]indolequinone-3-carboxylic acids and the demethylation of 2-methoxybenz[f]indolequinone are accompanied by oxidative dimerization and lead to the 3,3-dimers of 2-hydroxybenz[f]indolequinones.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1636–1641, December, 1978.     

Dimerization of α-ethylenic dithioesters

Methyl propenedithioate and three methyl 2-butenedithioates were prepared and all but one of these hetero-dienes gave dimers resulting from a [4 + 2] cycloaddition. Formation of a 1,5-dithiocin ring was also observed from the propenedithioate.     

Cathodic Dehalogenation with Dimerization. Dimerization in the Course of Reduction of Butyl Iodide

Electrochemical reduction of butyl iodide in methanol with a sodium methylate supporting electrolyte was studied. The yield of the dimeric product, octane, largely depends on the cathode material, with copper and iron (St.3 steel) being the most active. At a current density of 0.03-0.10 A cm^{- 2}, 0°C, and 0.005 M CH₃ONa, the yield of octane, based on butyl iodide, is as high as 83-84%.     

Dimerization of the pentafluoronitrobenzene radical-anion

Conclusions The radical-anion of pentafluoronitrobenzene generated by electrochemical reduction of its percursor in aprotic solvents was found capable of undergoing dimerization.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1155–1157, May, 1988.     

Head-to-Tail Dimerization of N-Heterocyclic Diazoolefins

The head-to-tail dimerization of N-heterocyclic diazoolefins is described. The products of these formal (3+3) cycloaddition reactions are strongly reducing quinoidal tetrazines. Oxidation of the tetrazines occurs in a stepwise fashion, and we were able to isolate a stable radical cation and diamagnetic dications. The latter are also accessible by oxidative dimerization of diazoolefins.