Sulphones theoretical studies

Various liquid chromatographic techniques have been frequently employed for the purification of commercial dyes for theoretical studies or for the exact determination of their toxicity and environmental pollution capacity. Thus, several sulphonated azo dyes were purified by using reversed-phase preparative HPLC. The chemical strctures, colour index names and numbers, and molecular masses of the sulphonated azo dyes included in the experiments are listed in Fig. 3.114. In order to determine the non-sulphonated azo dyes impurities, commercial dye samples were extracted with hexane, chloroform and ethyl acetate. Colourization of the organic phase indicated impurities. TLC carried out on silica and ODS stationary phases was also applied to control impurities. Mobile phases were composed of methanol, chloroform, acetone, ACN, 2-propanol, water and 0.1 M sodium sulphate depending on the type of stationary phase. Two ODS columns were employed for the analytical separation of dyes. The parameters of the columns were 150 X 3.9 mm i.d. particle size 4 /jm and 250 X 4.6 mm i.d. particle size 5 //m. Mobile phases consisted of methanol and 0.05 M aqueous ammonium acetate in various volume ratios. The flow rate was 0.9 ml/min and dyes were detected at 254 nm. Preparative separations were carried out in an ODS column (250 X 21.2 mm i.d.) using a flow rate of 13.5 ml/min. The composition of the mobile phases employed for the analytical and preparative separation of dyes is compiled in Table 3.33. 

Radicals and radical ions provide fruitful subjects of research. Room temperature fluorescence from the arylmethyl radicals Ph3C, Ph2CH- and PhCH2 and theoretical studies of rotational barriers in the benzyl cation, radical and anion as well as the singlet and triplet states of diphenylcarbene are typical examples of such contemporary studies. A very detailed paper considers the problems of the state assignment and reactivity of excited states of p-substituted benzyl radicals.Ketyl radicals containing the enthrone moiety and the 4-(methyl sulphonate) benzophenone ketyl radical anion are related studies in this field. 

The polarography of sulphones has been fairly extensively studied, sometimes with an analytical bias and sometimes with more theoretical interest. It is generally accepted that a two-electron reduction takes place, to sulphinate ... 

Dittmer and Christy64 studied the reactions of thiete sulphone. Included in these was an attempt to synthesize thiete itself, a highly strained olefin of theoretical interest, by the LAH reduction of thiete sulphone. The reduction was expected to be feasible since Bordwell and McKellin63 had found that thietane sulphone was readily reduced, but the only product that Dittmer and Christy isolated was 1-propanethiol (equation 23). Reduction of the thiete sulphone with sodium borohydride in basic aqueous methanol gave a 61% yield of the saturated ring, thietane sulphone. 

The process of obtaining alkyl sulphonate in an autoclave with a mixer has been studied. Basic reagents were water solution of sodium hydrosulfite 36-38% and industrial olefin fractions at 240-320 °C. NaN03 and oxygen from air were used as initiators of the reaction of free radicals. System factors are x, reaction time, h x2 temperature of reaction, °C x3 mole ratio of sodium hydrosulfite and olefin x3 mole ratio of NaN03 and olefin x5 volume ratio of N-propanol and olefin. System response is a yield of alkyl sulfonate as a per cent of theoretical yield. FRFE design... 

Despite the numerous polyesters described in the literature, it is only recently that the cyclic populations of ring-chain equilibrates of linear aliphatic polyesters have been characterised. This characterisation was based on the well-known investigations of Carothers 121, 122) and his co-workers and the studies of Billmeyer 123-125) and his group. In particular, Billmeyer s wodc established tetraisopropyltitanate as a catalyst for producing equilibrium between ring and chain molecules in polyester systems. This is in contrast to the catalyst, p-toluene sulphonic acid, used by Jacobson, Beckmann and Stockmayer 127) in what was effectively the first attempt to study experimentally and theoretically the change in the total cyclic population of... 

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