The Benzidine and Allied Colours, Their Composition, Properties and Application

Hurst, George H.

doi:10.1111/j.1478-4408.1888.tb01210.x

Cited by 3 publications

(3 citation statements)

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“…3,4 The structure of Direct Yellow 4 in neutral conditions is shown in Figure 1A. 5,6 In basic conditions, a hydrogen ion is removed from each phenol group (shown in red). 5,6 In very acidic conditions, a hydrogen ion is added to each azo group (shown in blue).…”

Section: ■ Backgroundmentioning

confidence: 99%

“…5,6 In basic conditions, a hydrogen ion is removed from each phenol group (shown in red). 5,6 In very acidic conditions, a hydrogen ion is added to each azo group (shown in blue). 7 Some sources have pointed out that turmeric, with its yellow-colored compound curcumin, can be used to make a yellow-colored paper that changes to red in basic solution.…”

Section: ■ Backgroundmentioning

confidence: 99%

“…Most goldenrod-colored paper sold today does not have color-changing capability; however, the color-changing goldenrod paper is still available from suppliers such as Educational Innovations, Bethel, CT. , The specific dye used in this color-changing goldenrod paper was not divulged by the company, but a few Internet sources claim it is Direct Yellow 4. This dye has a CAS number of 3051-11-4 and has a number of other names, including Brilliant Yellow, Paper Yellow CB, Color Index 24890, and 2,2′-(1,2-ethenediyl)bis[5-[(4-hydroxyphenyl)azo]-benzenesulfonicacid disodium salt. , The structure of Direct Yellow 4 in neutral conditions is shown in Figure A. , In basic conditions, a hydrogen ion is removed from each phenol group (shown in red). , In very acidic conditions, a hydrogen ion is added to each azo group (shown in blue) …”

Section: Introductionmentioning

confidence: 99%

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Demonstration Extensions Based on Color-Changing Goldenrod Paper

Schorr

Campbell

2018

J. Chem. Educ.

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For many years, a type of goldenrod-colored paper has been used as an indicator to demonstrate acid–base behavior, turning yellowish in acidic conditions and reddish in basic conditions. This pH sensitive color change has been the basis of demonstrations involving making hidden messages and pictures using techniques such as printing (e.g., to make a “bloody” red handprint), spraying, wax resist, and electrolytic processes. Candidate dye compounds for the goldenrod paper that feature a pH sensitive yellow/red color change include Direct Yellow 4 and curcumin. Direct Yellow 4, curcumin, and the color-changing goldenrod paper also all exhibit additional changes to darker colors in very acidic solutions (pH < 0). This paper provides evidence that Direct Yellow 4 (or a closely related compound) and not curcumin is the dye present in the color-changing goldenrod paper. These color changes of the Direct Yellow 4 in the goldenrod paper, in conjunction with the fact that paper sheets can display two-dimensional images or shaped into three-dimensional objects, lead to novel ways to demonstrate acid–base and other chemical concepts to audiences. For example, paper flowers made from the goldenrod paper will change from yellow to red in basic solutions, to black in very acidic solutions, to off-white in sodium hypochlorite solutions, and to purple-black in iodine solutions.

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Section: ■ Backgroundmentioning

confidence: 99%

Section: ■ Backgroundmentioning

confidence: 99%