STUDIES IN THE POLYOXYPHENOL SERIES: VII. THE OXIDATION OF VANILLIN WITH SODIUM CHLORITE AND CHLORINE DIOXIDE

1955 ◽  
Vol 33 (1) ◽  
pp. 68-81 ◽  
Author(s):  
R. M. Husband ◽  
C. D. Logan ◽  
C. B. Purves
Keyword(s):  
Chlorine Dioxide ◽  
Crystalline Substance ◽  
Sodium Chlorite ◽  
Effect Of Ph ◽  
Aqueous Sodium ◽  
White Crystalline Substance

Vanillin almost instantly reduced 1.2 to 1.5 moles of aqueous chlorine dioxide at 20 °C. or 5 °C. and any pH between 1.2 and 6.5, and a white crystalline substance with the composition of a dihydroxyvanillin, C7H5O4(OCH3), was isolated in roughly 25% yield independently of the pH. When oxidized with aqueous sodium chlorite at 20 °C. and pH 0.5, these crystals gave another crystalline substance with the composition of a dihydroxyvanillic acid, C7H5O5(OCH3). Although both these substances decomposed readily to red oils and then to brown powders free of methoxyl groups, seven well characterized derivatives were prepared. The results showed that the substances were unsaturated, monohydroxy, diketone tautomers of a dihydroxyvanillin and the corresponding dihydroxyvanillic acid, but precise structures could not be assigned. Parallel oxidations of vanillin with aqueous sodium chlorite at 20 °C. and pH 6 proceeded at a negligible rate, but near pH 5 a reaction that often seemed autocatalytic produced about 19% of 5-chlorovanillin. At pH 4 the aldehyde C7H5O4(OCH3) was isolated in 19% yield; at pH 1 this aldehyde (15%) was mixed with 7.7% of the corresponding acid C7H5O5(OCH3), but at pH 0.5 the latter alone was produced (28%). Chlorine dioxide and sodium chlorite therefore differed markedly in their oxidizing action and in the effect of pH upon it. When acting on vanillin, both oxidants also produced deep red, unstable oils with quinone-like properties and often containing chlorine.

STUDIES IN THE POLYOXYPHENOL SERIES: VIII. THE OXIDATION OF SUBSTANCES RELATED TO VANILLIN WITH SODIUM CHLORITE AND CHLORINE DIOXIDE

1955 ◽  
Vol 33 (1) ◽  
pp. 82-96 ◽  
Author(s):  
C. D. Logan ◽  
R. M. Husband ◽  
C. B. Purves
Keyword(s):  
Hydrogen Peroxide ◽  
Chlorine Dioxide ◽  
Sodium Chlorite ◽  
Veratric Acid ◽  
Simultaneous Formation ◽  
Aqueous Sodium ◽  
Sharp Distinction ◽  
Slow Reaction ◽  
Ph Values ◽  
Chlorous Acid

The research confirmed the fact that chlorine dioxide and sodium chlorite were not equivalent in their oxidizing properties. At 22 °C. or less, the oxidation of pyrogallol by aqueous sodium chlorite at pH 6 was very slow, but became very rapid on the acid side of pH 3.5. The amorphous, colored products probably did not include purpurogallin. Under similar circumstances p-hydroxybenzaldehyde was unaffected at pH 6; 22% was oxidized to p-benzoquinone (Dakin's reaction) at pH 5, and this amount increased to 39% at pH 1. The yield of benzoquinone was about 24% regardless of pH within the above range when aqueous chlorine dioxide was the oxidant. Sodium chlorite at pH 0.9 produced a 91% yield of methoxy-p-quinone from methoxy-p-hydroquinone; at pH 4 this product was mixed with 56% of 4,4′-dimethoxydiquinone, but near pH 6 a slower oxidation did not proceed beyond 4,4′-dimethoxyquinhydrone. Aqueous chlorine dioxide yielded at least 92% of monomeric methoxyquinone at all pH values between 1 and 6, probably in accord with the equation,[Formula: see text] The simultaneous formation of hydrogen peroxide was suspected, but not proved. In sharp distinction to the behavior of free phenols, veratraldehyde was not oxidized by aqueous chlorine dioxide between pH 6 and pH 3, but at pH 1 a slow reaction yielded up to 15% of veratric acid. Sodium chlorite produced about 92% of the same acid at pH 1 and pH 4, but its action was negligible at pH 5. Since by-product chlorine dioxide was ineffective at pH 4, it was possible to confirm the validity of the Jeanes–Isbell equation for the reduction of chlorous acid:[Formula: see text]The oxidation of acetylated vanillin was complicated by the occurrence of deacetylation. Red, chlorinated oils with quinoidal properties were also formed in most of the above oxidations.

scholarly journals IX. On parasulphide of phenyl and parasulphobenzine

1870 ◽  
Vol 18 (114-122) ◽  
pp. 542-543 ◽  
Keyword(s):  
Crystalline Substance ◽  
Vacuum Filter ◽  
Carbonaceous Matter ◽  
Isomeric Compound ◽  
White Crystalline Substance ◽  
Iron Tube

When sulphide of phenyl, C 6 H 5 C 6 H 5 }S, was passed several times in succession through an iron tube filled with nails and heated to low redness, a considerable amount of carbonaceous matter was deposited, and a portion of the sulphide was converted into an isomeric compound, which I propose to call Parasulphide of Phenyl. In order to obtain this substance from the dark-coloured distillate which collected in the receiver when sulphide of phenyl was submitted to the action of heat in the manner above described, it was transferred to a copper retort and distilled. The clear dark-yellow oil was then cooled for several hours in a freezing-mixture, when a considerable quantity of a white crystalline substance separated in nodules; this is freed from undecomposed sulphide of phenyl by thoroughly draining it on a vacuum filter. It can readily be purified by repeated crystallization from boiling alcohol, in which it is rather soluble.

An Evaluation of Historical Bleaching with Chlorine Dioxide Gas, Sodium Hypochlorite, and Chloramine-T at the Fogg Art Museum

2012 ◽  
Vol 33 (3-4) ◽  
Author(s):  
Theresa Smith
Keyword(s):  
Twentieth Century ◽  
Formic Acid ◽  
Sodium Hypochlorite ◽  
Chlorine Dioxide ◽  
Art Museum ◽  
Sodium Chlorite ◽  
Chlorine Dioxide Gas ◽  
Brightness Reversion ◽  
Chloramine T

AbstractIn the mid-twentieth century, drawings by Jean-Auguste-Dominique Ingres at the Fogg Art Museum were treated with chemical bleaches such as chlorine dioxide gas, sodium hypochlorite, and chloramine-T. Fifty years later, the darkened condition of the drawings was attributed to bleaching with chlorine dioxide gas. This paper discusses the three methods developed by Rutherford John Gettens to generate chlorine dioxide gas from sodium chlorite, formaldehyde and formic acid, examines the use of these bleaching methods to treat Ingres drawings at the Fogg, and discusses the sodium hypochlorite and chloramine-T bleaching methods also in use at the time. The treatments of two Ingres drawings are compared and evaluated in light of later bleaching studies and the current condition of each drawing. All of these historical bleaching methods, as practiced on the works studied, contributed to the darkening and colour/brightness reversion of drawings.

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