Anthroquinones

Figure B 1.16.9 shows background-free, pseudo-steady-state CIDNP spectra of the photoreaction of triethylamine with (a) anthroquinone as sensitizer and (b) and (c) xanthone as sensitizer. Details of the pseudo-steady-state CIDNP method are given elsewhere [22]. In trace (a), no signals from the p protons of products 1 (recombination) or 2 (escape) are observed, indicating that the products observed result from the radical ion pair. Traces (b) and (c) illustrate a usefiil feature of pulsed CIDNP net and multiplet effects may be separated on the basis of their radiofrequency (RF) pulse tip angle dependence [21]. Net effects are shown in trace (b) while multiplet effects can...

Dyes are miscible with the polymer and hence do not have dispersion problems. They include many of the dyes that have been developed for dying fibres, e.g., azo and anthroquinone derivatives. They are particularly useful for transparent articles, e.g., automotive taillights, decorative film. They can be added either as a dry powder or as a colour concentrate (requiring 10-fold dilution). 

Bromoamine acid contaminated soil Bromoamine acid (an intermediate of anthroquinone dye) Sphingomonas herbicidovorans [87]... 

Jang and McDow (1997) studied the photodegradation of benzo[a]anthracene in the presence of three common constituents of atmospheric aerosols reported to accelerate benzo [a] anthracene, namely 9,10-anthroquinone, 9-xanthone, and vanillin. The photo-degradation experiments were conducted using a photochemical reactor equipped with a 450-W medium pressure mercury arc lamp and a water bath to maintain the solution temperature at 16 °C. The concentration of benzo [a] anthracene and co-solutes was 10" M. Irradiation experiments were conducted in toluene, benzene, and benzene-c/e- Products identified by GC/MS, FTIR, and NMR included benzo[a]an-thracene-7,12-dione, phthalic acid, phthalic anhydride, 1,2-benzenedicarboxaldehyde, naphtha-lene-2,3-dicarboxylic acid/anhydride, 7,12-dihydrobenzo[a]anthracene, 10-benzyl-10-hydroan-thracen-9-one, benzyl alcohol, and 1,2-diphenylethanol. 

The half-wave reduction potentials for a series of annelated 1,4 naphthoquinones (102-106) increase upon alkylation, and decrease as ring size decreases (Table 13). The more cathodic reduction potentials of 2,3-dimethylnaphtho-l,4-qui-none (106, 0.846 V) and l,2,3,4-tetrahydro-9,10-anthroquinone (105,0.854 V) as compared to 1,4-naphthoquinone (0.685 V) are expected from inductive electron donation of alkyl groups. A decrease in reduction potential from 105 to 2,3-cyclobutanaphtho-l,4-quinone (103) (0.695 V) as ring size decreases is observed such that the reduction potential of 103 is only slightly higher than the parent 1,4-naphthoquinone. 

Radical 44 is generated by electron transfer from the parent pyrimidine to the optically generated (308 nm laser pulse) triplet states of anthroquinone-2,6-disulfonic acid. The experimental method detects transient species in the time range of 40 ns to 10 ps after the laser pulse. At pH = 1.0, the primary cation radical is the only radical found 40 ns after the pulse. The spectrum of this radical disappears at a time shorter than 1.0 ps after the pulse. A second spectrum observed 5 ps after the pulse, is attributed to radical 46, which was thought to form by net OH- addition to C6 of the cation radical. At pH = 7.0, the N3... 

Dimethylamino-anthroquinone. See Bis(me-thylamino)-anthraquinone in Vol 2 of Encycl, p B148-R... 

C-Glycosyl compounds have a carbon atom in place of the exocyclic oxygen atom of the acetal group and, therefore, are branched cyclic ethers. An example is the naturally occurring anthroquinone dye, caoninic acid [1260-17-9] (Cl Natural Red 4). 

Figure 17. Schematic representation for two-step activation of electron transport across a vesicle wall. ZnP is octadecyl-pyridiniumyltris(4-pyridyl)porphyrinatozinc(II) cation. DBA is 1,3-dibutylalloxazine, AQDS is 9,10-anthroquinone-2,6-disulfonate (reproduced from ref. 328)...

Matsuda, H. et al., Antioxidant constituents from rhubarb structural requirements of stilbenes for the activity and structures of two new anthroquinone glucosides, Bioorg. Med. Chem., 9, 41-50, 2001. 

Photo-oxidation of DMS Aqueous DMS is readily photo-oxidized by visible light in the presence of photosensitizers (e.g., methylene blue, anthroquinone) or humic acid and rose bengal which are naturally... 

Methyl K-amyl carbinol, 7, 62 Methyl m-Amyl Ketone, 7, <5o, 62 i3-Methyl Anthroquinone, 4, 43 Methylation, 6, 64, 94, 96 Methylation by means of formaldehyde, 1, 75> 79 2, 17 3, 67 Methyl benzoate, 3, 71, 72 Methyl bromide, 3, 29 Methyl m-Butyl Ketone, 7, 62 Methyl mo-Butyl Ketone, 7, 62 Methyl scc-Butylmethyl Ketone,... 

Figure 5.15 Cyclic voltammograms obtained for a mercury electrode immersed in a 5 mM solution of 2,7-AQDS as the pH of the unbuffered contacting electrolyte solution (0.1 M UCIO4) is varied by using either HCIO4 or NaOH. The pH values, from left to right, are 2.8, 3.5, 4.8 and 6.1. The scan rate is 0.1 V s, with an initial potential of —1.000 V. The inset shows the dependence of the formal potential on the solution pH in unbuffered solution. Reprinted from. Electroanal. Chem., 498, R. J. Forster and J. P. O Kelly, Protonation reactions of anthroquinone-2,7-disulfonic acid in solution and within monolayers, 127-135, Copyright (2001), with permission of Elsevier Science...

Methyl anthroquinone, IV, 43-44 Methyl benzoate, III, 71, 72 Methyl bromide, III, 29 Methylene aminoacetonitrile, IV, 31, 47-48... 

Polyamide precoated plates are currently used for the separation of phenols and phenolic compounds (i.e., anthocyanins, anthoxanthines, anthroquinone derivatives, and flavones) using solvents of different elution strength (DMF > formamide > acetone > methanol > water). Such eluents and solutes compete for the hydrogen bonds with the peptide groups of the polyamide. 

Berglin, T. and Schoon, N., Selectivity aspects of hydrogenation stage of the anthroquinone process for hydrogen peroxide production, Ind. Eng. Process Des. Dev., 22 150-153 (1983). 

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