四(α-高歧化度烷氧基)酞菁合成关键步骤的研究

烷氧基邻苯二腈是酞菁合成的重要中间体,但高歧化度烷氧基邻苯二腈的合成由于副产物多,产率低下而成为此类酞菁应用的"瓶颈".文中对反应副产物进行了分离纯化,并利用红外、气质联用、1HMR和元素分析等测试手段对其进行了表征.且根据测试数据推导出了副产物结构式为1,2,1'2' 四腈基 3,3' 二苯基醚.这一副反应机制的阐明,对于寻求对主反应有利的条件,具有重要的意义.     

IN SITU IR SPECTROSCOPIC STUDIES OF HCOOH DECOMPOSITION OVER V-TI-O CATALYST

Decomposition of formic acid over V-Ti-O catalysts was studied by in situ IR spectroscopy. Four surface compounds, among which are H-bonded acid, one mono- and two bidentate formates (BF1 and BF2), were identified in the temperature range of 100-190°C. The activation energy and rate of the BF2 decomposition were found equal to those for the CO formation. This equality points to the involvement of BF2 in the HCOOH decomposition into carbon monoxide.     

An open chain product in the reaction of benzil with thiocarbohydrazide

An open chain compound was obtained by reaction of benzil with thiocarbohy-drazide in acidic condition. Its derivative, namely, benzil bis-(5-isopropylidene-3-thiocarbohydrazone) has been structurally characterized by X-ray single crystal diffraction method. Crystallographic data: C22H26N8S2, Mr=466.62, monoclinic, space group C2/c, a=12.215(3), b=11.473(2), c=17.032 (3)A, B=98.96(2)0, V=2357.7(9)A3, Z=4, Dc=1.32 g/cm3, F(000)=1040, u(Mo Ka)=2.43 cm-1. Final R=0.050, Rw=0.061 for 1103 unique and observed reflections with I> 3o(I). The effect of the structures on the formation of the open-chain intermediates during the cyclization of (2:2) Schiff base macrocyclic compound has been discussed and a possible mechanism for the ring closure has been suggested.     

Multistep electrochemical reactions involving transport of intermediates between the near-electrode layer and the bulk solution: A kinetics analysis based on theory of generalized variables (theory of similarity)

A kinetic analysis of multistep electrochemical reactions involving partial diffusion transport of intermediates between the near-electrode layer and the bulk electrolyte is performed within theory of generalized variables (theory of similarity). Dimensionless complexes (similarity criteria) that characterize such reactions are obtained, and their values corresponding to the transport of intermediates are determined.Translated from Elektrokhimiya, Vol. 41, No. 1, 2005, pp. 121–125.Original Russian Text Copyright © 2005 by Protsenko, Danilov.     

血小板阻聚药物中间体N-环己基-5-氯丁基-1H-四氮唑的合成

以δ-戊内酯和环己胺为原料合成了抗血小板聚集药物西洛他唑的重要中间体N-环己基-5-氯丁基-1H-四氮唑，选择了合适的相转移催化剂及安全的叠氮试剂并获得较高的收率。     

SYNTHESIS OF FUNCTIONAL MACROMOLECULE INTERMEDIATE THROUGH ACYLATION CATALYZED BY [Emim]Cl-AlCl3 IONIC LIQUID

Acylation reaction of anthracene with oxalyl chloride in the presence of [Emim]Cl-AlCl3 ionic liquid has been investigated. Pure 1,2-aceanthryenedione, which is used as intermediate of functional aromatic polymer material, was obtained by recrystalling the reaction mixture with aether and was determined by GC/MS, 1↑HNMR and FTIR analysis. The influences of various parameters, such as the contents of AlCl3 in [Emim]Cl-AlCl3, the amount of acylation agent, amount of [Emim]Cl-AlCl3, reaction temperature and reaction time were investigated. The optimum conditions were as follows： the molar fraction of AlCl3 in ionic liquid [x（AlCl3）] being 0.67, molar ratio of ionic liquid to anthracene being 2：1, molar ratio of oxalyl chloride to anthracene being 2：1, reaction temperature being 40℃ and reaction time being 6h. Under above conditions, the yield and selectivity of 1,2-aceanthrylenedione can reach 91.5% and 98.3% respectively. Further more, [Emim]Cl-AlCl3 ionic liquid, compared with metal halides such as AlCl3, was found to catalyze the reaction as a novel environmental friendly catalyst and solvent and can be reused.     

Reaction of sulphate radical anion (SO<Superscript>.</Superscript><Subscript>4</Subscript><Superscript>-</Superscript>) with hydroxy-and methyl-substituted pyrimidines: a pulse radiolysis study

Reactions of sulphate radical anion (SO·₄ ^-) with 4,6-dihydroxy-2-methyl pyrimidine (DHMP), 2,4-dimethyl-6-hydroxy pyrimidine (DMHP), 6-methyl uracil (MU) and 5,6-dimethyl uracil (DMU) have been studied by pulse radiolysis at pH 3 and at pH 10. The transient intermediate spectra were compared with those from the reaction of hydroxyl radical (·OH). It is proposed that SO·₄ ^- produces radical cations of these pyrimidines in the initial stage. These radical cations are short-lived except in the case of DMHP where a relatively longer lived radical cation is proposed to be formed. When there is a hydrogen atom attached to the N(1) or N(3) position, a deprotonation from these sites is highly favored. When there is no hydrogen attached to these sites, deprotonation from a substituted methyl group is favored. At acidic pH, deprotonation from nitrogen is observed for DHMP, MU and DMU. At basic pH, the radical cation reacts with OH^- leading to the formation of OH adducts.     

Kinetic Regularities Governing the Reaction of Electrodeposition of Iron from Solutions of Citrate Complexes of Iron(III)

The kinetics of a multistep reaction of electrodeposition of iron out of aqueous citrate-containing solutions of trivalent iron is investigated. It is shown that concentrations of major solution components affect the partial current density of discharge of ions of divalent iron. It is established that the deposition of metallic iron occurs as a result of discharge of intermediates, which are hydroxy complexes of divalent iron. Kinetic parameters and mechanism of the reaction of discharge of complexes [FeOH]⁺ to a metallic state are determined. It is mentioned that the formation of poorly soluble hydroxy compounds of trivalent iron in a near-electrode layer leads to a decrease in the iron deposition current.     

Modeling and simulation of free radical polymerization of styrene under semibatch reactor conditions

The first part of this approach is concerned with the elaboration of a radical polymerization model of styrenne, based on a kinetic diagram that includes chemical and thermal initiation, propagation, termination by recombination and chain transfer to the monomer. Furthermore, volume contraction during polymerization is considered, as well as the gel and glass effects. The mathematical formalism that describes the model in terms of moments is explored in detail. The model was then used to predict the changes in monomer conversion and molecular weight after intermediate addition of initiator and monomer. The results of this operation are dependent on the conditions of the reaction mass, quantity, and moment of substance addition. Therefore, the simulations were performed at different times with respect to the gel effect; before, during and after this phenomenon, and also with respect to different temperatures and initiators. Increasing the initiator concentration before the gel effect leads to an earlier appearance of the phenomenon and to a decrease in molecular weight. The ratio reveals a polydispersity index smaller for the intermediate addition of initiator. No significant changes take place during or after the gel effect. If along with the initiator, unreacted monomver (used to dissolve the initiator) enters the reactor, a small dip in conversion is observed. The general conclusion of this paper reveals the intermediate addition of initiator as a method to control polymer properties and to prevent the “dead-end” polymerization of styrene.     

Analysis of Equilibrium and Kinetics of Chromium-Fluoride Complexation from Spectroscopic Data via Chemometrics Methods

IntroductionStudies on reversible kinetic systems are consi-dered as a hotspot of chemical and biochemical kineticresearches[1,2]. Of late, some researches have been fo-cused on the simultaneous optimization of the obverseand reverse rate constants[3,4].H…