Micelle anthraquinone

An aqueous dispersion of a disperse dye contains an equilibrium distribution of solid dye particles of various sizes. Dyeing takes place from a saturated solution, which is maintained in this state by the presence of undissolved particles of dye. As dyeing proceeds, the smallest insoluble particles dissolve at a rate appropriate to maintain this saturated solution. Only the smallest moieties present, single molecules and dimers, are capable of becoming absorbed by cellulose acetate or polyester fibres. A recent study of three representative Cl Disperse dyes, namely the nitrodiphenylamine Yellow 42 (3.49), the monoazo Red 118 (3.50) and the anthraquinone Violet 26 (3.51), demonstrated that aggregation of dye molecules dissolved in aqueous surfactant solutions does not proceed beyond dimerisation. The proportion present as dimers reached a maximum at a surfactant dye molar ratio of 2 5 for all three dyes, implying the formation of mixed dye-surfactant micelles [52]. 

The high surface charge on a micelle (10 volts/a or 300m-volts/micelle) can strongly participate in redox exchange reactions (11). For example, the equilibrium between anthraquinone sulfonate (AQS ) and duroquinone (DQ) and their reduced forms... 

ZnTPP (Hambright, Washington D.C.), duroquinone (DQ) (Aldrich) and methyl viologen (MV+2) (BDH CHEMICALS) were used without further purification. The sodium salt of anthraquinone 2-sulphonate (AQS) (BDH CHEMICALS) was recrystalized from methanol. Benzyldimethyl-n-hexadecylammonium chloride (BHDC) (BDH CHEMICALS) was dried over P205 and stored under vacuum. The solvent, benzene (pro-analysis) (BDH CHEMICALS) was dried and distilled over sodium wire. Stock solutions of reversed micelles were prepared by adding dropwise the calculated amount of water to the appropriate solution of BHDC. The surfactant concentration used throughout the experiments was 0.1 mol dm 3. 

Photosensitized vectorial electron transfer from the (morpholine)ethenesulfonate anion (MES ) to 1,5-anthraquinone disulfonate (AQDS ) mediated by dibutyl (BTDB) or diethyl (BTDE) esters of 2,l,3-benzothiadiazole-4,7-dicarboxylic acid solubilized in CTAB micelles has also been reported [73], The proposed mechanism of BTD-mediated electron transfer is shown in Figure 7, where reductive quenching of photoexcited BTD by interfacially adsorbed MES is followed by electron transfer from reduced BTD to the AQDS , recycling the sensitizer. 

CT complexes are formed and electron transfer occurs from excited molecules of anthracene derivatives to methylviologen in aqueous micellar media. Methylene blue quenches pyrene fluorescence by electron transfer in SDS micelles . E.lectron transfer between anthraquinone sulphonate radicals and duroquinone in SDS micellar solution occurs in the aqueous phase there is no evidence of intramicellar transfer. Photoionisation of... 

Me R = Br, R = H) by various donors in viscous soJventa are decreased by a factor of <2 in a 0.34 T magnetic field and pressure is reported to accelerate the photoreduction of p-benzoquinone in SOS and CTAB micelles in Aerosol OT reversed micelles, the reaction is retarded.The yield of anthraquinone-2-sulphonate radical anion (AQS) generated by irradiation of AQS in aqueous acetonitrile containing propan-2-oJ has been found to depend on the water concentration and to follow Perrin s equation.Complexation of aryl alkyl ketones with /3-cyclodextrin leads to changes in the ratio of the products of elimination and cyclisation which result from reaction of the... 

Electron transport across organised bilayers is an integral part of biological energy storage systems such as photosynthesis and provides a means of controlling back electron transfer and of separation of the products of redox reactions. Esters of 2,l,3-benzothiadiazole-4,7-dicarboxylic acid (481) have been used to study the transfer of electrons from 2-(morpholino)ethanesulfonic acid (MES) to 1,5-anthraquinone disulfonate in micelles or across vesicle bilayers. The esters absorb the light, accept an electron from MES and transfer it to the... 

Photochemical processes in heterogeneous systems, and across micelle boundaries in particular, clearly has great potential. The photolysis of amphipathic alkylcobaloximes in mixed micelles shows a co-operative effect owing to structure.The photoreduction of anthraquinone in aqueous micellar solution has been compared with that in non-aqueous solution.The dimerization of 3-(n-butyl)cyclopentenone is solvent-dependent and the ratio of isomeric products depends on surfactant concentration. It is suggested that this can be used as a means of critical micellar concentration determination. 

The photoinduced reduction of some quinones by zinc porphyrin and also by its tetraphenyl derivative has been studied in micellar systems. The mean time for intramicellar electron transfer has been established as 0.2 ps, and for duroquinone the rates of entry and exit from the micelle have been found to be 5 x 10 m s and6 x 10 m s respectively. Quinones possessing long chains are less mobile and partial charge separation could be achieved. Irradiation of anthraquinone in aqueous sodium dodecyl sulphate leads to anthraquinol and the surfactant-anthrahydroquinone ether as major products via the triplet state of the anthraquinone. ... 

Irradiation of sodium anthraquinone sulphonates in micelles leads to photoreduction to the corresponding radical anions, whose lifetimes are much lengthened compared with those obtained in the absence of surfactants.31 It is reported that photoreduction of anthraquinone sulphonates in basic water-alcohol solutions can lead on to desulphonation of the 9,10-dihydroxyanthracenes which are produced.32 Photoreduction of sodium l,2-naphthoquinone-4-sulphonate in water gives the 1,2-dihydroxy-compound.33 In this reaction,... 

---