Evaluation of the stability and analysis of halogenated furanones in disinfected drinking waters

A refined method for the sub-nanomolar analysis of 13 halogenated furanones in chlorinated drinking water is proposed which uses liquid-liquid extraction, methylation where necessary, gas chromatographic separation, and either micro-electron capture or ion trap mass spectrometric detection. Liquid-liquid extraction with methyl tert-butyl ether was demonstrated to be effective for recovery of halogenated furanones. Confirmation of the halogenated furanones identity and reduction of natural organic matter interference were achieved by ion trap tandem mass spectrometry. Compound stabilities and procedural efficiencies were evaluated to permit optimization of the method for reasonable sample volumes and a 1000:1 pre-concentration factor that would permit feasible sample collection in the field. Both chlorinated and brominated analogues of MX (3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone) were included in a suite of compounds targeted in a national occurrence study of disinfection by-products.     

New derivatization method for determination of 3-chloro-4(dichloromethyl)-5-hydroxy-2(5H)-furanone in water

An extremely potent mutagen, 3-chloro-4(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX) is commonly present in chlorinated drinking water. Due to its high mutagenic activity and according to World Health Organization guidelines its concentration should be controlled in drinking waters. Determination of MX is difficult due to ppt levels at which the compound usually exists in drinking waters. Derivatization of MX with 2-propanol is presented as a method which significantly lowers the GC–MS detection level compared to other alcohol derivatization agents.     

Photochemical synthesis of a palladium dichloromethyl complex, {(hexyl)HC(N-methyl-imidazol-2-yl)2}Pd(CHCl2)Cl.: X-ray molecular structures of {(hexyl)HC(N-methylimidazolyl-2-yl)2}Pd(X)Cl, X=Cl, and CHCl2

The reaction of (hexyl)HC(mim)₂ (1, mim=N-methyl-imidazol-2-yl) with (cod)PdMeCl in C₆H₆ yields {(hexyl)HC(mim)₂}Pd(Me)Cl (3). The photochemical reaction of 3 with CH₂Cl₂ at 23 °C in ambient room light yields {(hexyl)HC(mim)₂}Pd(CHCl₂)Cl (4). It is proposed that this reaction proceeds by homolytic scission of the PdMe bond of 3.     

Synthesis of tetrachloroisophthalic and-terephthalic aldehydes and stable bis(nitrile oxides) based on them

A new route for the synthesis of 2,4,5,6-tetrachloroisophthalic and 2,3,5,6-tetrachloroterephthalic aldehydes from the corresponding tetrachlorobenzenes was developed. The method involves dichloromethylation of the initial compounds with chloroform in the presence of aluminum chloride and subsequent hydrolysis of the resulting 1,3-bis(dichloromethyl)-2,4,5,6-tetrachlorobenzene and 1,4-bis(dichloromethyl)-2,3,5,6-tetrachlorobenzene. Stable 2,4,5,6-tetrachlorobenzene-1,3-dicarbonitrile oxide and 2,3,5,6-tetrachlorobenzene-1,4-dicarbonitrile oxide were obtained for the first time from the above aldehydesvia the corresponding oximes. The products were characterized by IR and¹³C NMR spectra, and were converted into substituted 1,3- and 1,4-phenylenebis(isoxazolines) using 1,3-dipolar cycloaddition with styrene. Translated fromIzvestiya Akademit Nauk. Seriya Khimicheskaya, No. 1, pp. 106–109, January. 1997.     

Spektroskopische und röntgenographische Untersuchungen an Dichlormethyl-Quecksilberverbindungen

Spectroscopic and X-Ray Structural Investigations on Dichloromethyl Mercury Compounds Bis(dichloromethyl)mercury, Hg(CHCl₂)₂, and mixed alkyl compounds RHgCHCl₂ (with R = CH₃, C₂H₅) have been synthesized by known methods from CH₂Cl₂, lithium butanide and HgCl₂, CH₃HgCl or C₂H₅HgCl, respectively. The ¹H-, ¹³C-NMR as well as the IR and Raman spectra of the liquid alkyls RHgCHCl₂ and the high melting Hg(CHCl₂)₂ have been measured and assigned. According to the X-ray structure determination Hg(CHCl₂)₂ crystallizes in the monoclinic space group P2₁/c with 4 non-symmetric molecules per unit cell (R = 0.046).     

Thermodynamic and kinetic characteristics of intermediates of electrode reactions. Comparative laser photoemission study of the kinetics of electron transfer for certain alkylaryl and alkylhalide radicals

Using the laser photoemission technique, a comparative study of thermodynamic and energy characteristics of electron transfer (ET) is carried out for a number of alkylaryl intermediates (IM) (benzyl, benzhydryl radicals) and alkyl halides (chloromethyl and dichloromethyl radicals). It is found that the standard free energies of activation of radicals under study are 0.34–0.38 eV and the preexpoential factors are between 10⁹ and 10¹⁰s^?1 and weakly depend on the solution nature. The reorganization energies of the medium for these IM are estimated in terms of the classical Marcus theory. The results are compared with the literature data on the dissociative ET in monohalogenomethanes CH₃Hal/CH₃Hal^?·, polychloromethanes CH_nHal_{4 ? n} /CH_nHal _4?n ^?· , and some other systems. Possible reasons for the different probabilities of observing reversible ET for IM under study are discussed.     

Theoretical mechanistic study on the radical-molecule reaction of CHCl2/CCl3 with NO2

The radical-molecule reaction mechanism of CHCl(2) and CCl(3) with NO(2) have been explored theoretically at the B3LYP/6-311G(d,p) and MC-QCISD (single-point) levels. For the singlet potential energy surface (PES) of CHCl(2) + NO(2) reaction, the association of CHCl(2) with NO(2) was found to be a barrierless carbon-to-nitrogen approach forming an energy-rich adduct a (HCl(2)CNO(2)) followed by isomerization to b(1) (trans-cis-HCl(2)CONO), which can easily interconvert to b(2), b(3), and b(4). Subsequently, the most feasible pathway is the 1,3-chlorine migration associated with N-O1 bond cleavage of b(1) leading to P(1) (CHClO + ClNO). The second competitive pathway is the 1,4-chlorine migration along with N-O1 bond rupture of b(4) giving rise to P(2) (CHClO + ClON). Moreover, some of P(1) and P(2) can further dissociate to give P(6) (CHClO + Cl + NO). The lesser followed competitive channel is the 1,3-H-shift from C to N atom along with N-O1 bond rupture of b(1) to form P(3) (CCl(2)O + HNO). The concerted 1,4-H-shift accompanied by N-O1 bond fission of b(3) to product P(4) (CCl(2)O + HON) is even much less feasible. For the singlet PES of CCl(3) + NO(2) reaction, the only primary product is found to be P(1) (CCl(2)O + ClNO), which can lead to P(2) (CCl(2)O + Cl + NO) via dissociation of ClNO. The obtained major products CHClO and CCl(2)O for CHCl(2) + NO(2) and CCl(3) + NO(2) reactions, respectively, are in good agreement with kinetic detection in experiment. Compared with the singlet pathways, the triplet pathways may have less contributions to both reactions. Because the rate-determining transition state involved in the feasible pathways lie above the reactants R, the title reactions may be important in high-temperature processes. The similarities and discrepancies among the CH(n)Cl(3-n) + NO(2) (n == 0-2) reactions are discussed in terms of the substitution effect. The present study may be helpful for further experimental investigation of the title reactions.     

氯化消毒副产物2-氯-5-酮-3-烯-己二酰氯的质谱分析

2－氯－4－（二氯甲基）－5－羟基－2（H）－呋喃酮（MX）是饮用水氯化消毒过程中产生的一种具有强致突变性的消毒副产物（DBPs)，在对MX的前驱物模拟氯化过程中，发现在MX峰的附近有一峰，有时干扰MX的测定；作者对该未知峰的质谱图进行了解析，初步推断其结构可能为2－氯－5－酮－3－烯－己二酰氯（2－chloro-5-oxo-3-hexene diacyl chloride,COHC).     

含吡啶、噻吩环大环化合物的合成及其与Cu(Ⅱ)的配合行为

以2，6－二溴甲基吡啶及2，5－二氯甲基噻吩分别与对甲基苯磺酰胺进行缩合反应得到新的大环化合物1，9，17，25－四对甲基苯磺酰基大环多胺｛[32]-Py4N4Ts4｝与1，8，15，22－四对甲基苯磺酰基大环化合物｛[28]-Th4N4Ts4｝。其中[32]－Py4N4Ts4在浓硫酸中脱去四个对甲基苯磺酰基后又得到新的大环多胺化合物[32]-Py4N4H4，并由紫外吸收光谱测定出其与Cu（Ⅱ）配合的配位比为1：2，证明形成了双核配合物。     

Bromination of 4‐Dichloromethyl‐4‐methylcyclohexa‐2,5‐dien‐1‐ones

Bromination of 4‐dichloromethyl‐4‐methylcyclohexa‐2,5‐dien‐1‐one and 4‐dichloromethyl‐3,4‐dimethylcyclohexa‐2,5‐dien‐1‐one has been studied. The reaction conditions required for the formation of mono‐, di‐, and tribrominated products have been optimized.