para-Dimethylaminobenzaldehyde

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para-Dimethylaminobenzaldehyde
Para-Dimethylaminobenzaldehyde.png
Identifiers
CAS number 100-10-7 YesY
PubChem 7479
ChemSpider 7199 YesY
Jmol-3D images Image 1
Properties
Molecular formula C9H11NO
Molar mass 149.19 g mol−1
Appearance yellow-white powder
Density 1.1 g/mL
Melting point 74 °C (165 °F; 347 K)
Boiling point 176–177 °C
Solubility in water 0.3 g/L
Hazards
MSDS External MSDS
EU classification Harmful Xn
Flash point 164 °C (327 °F; 437 K)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
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Infobox references

para-Dimethylaminobenzaldehyde is an organic compound containing amine and aldehyde moieties which is used in Ehrlich's reagent for determination of hydrazine and Kovac's reagent for microbiology's indole test.

Urobilinogen determination[edit]

It is used in Ehrlich's reagent, which may be used as a stain in thin layer chromatography, or as a reagent to detect urobilinogen in fresh, cool urine. If a urine sample is left to oxidize in air to form urobilin the reagent will not detect the urobilinogen. By adding few drops of reagent to 3 mL of urine in a test tube one can see a change of color from above, to dark pink or red. The degree of color change is proportional to the amount of urobilinogen in the urine sample.

Ehrlich's reagent is a strong electrophile which reacts with the electron-rich α-carbon of indole rings to form a blue-colored adduct.[citation needed] It can be used to detect the presence of indole alkaloids. Not all indole alkaloids give a colored adduct as result of steric hindrance which does not allow the reaction to proceed.[citation needed]

Hydrazine determination[edit]

p-Dimethylaminobenzaldehyde reacts with hydrazine to form an azo-dye, which has a distinct yellow color. It is therefore used for spectrophotometric determination of hydrazine in aqueous solutions at 457 nm.[1]

Isaac Asimov essay[edit]

Isaac Asimov, in a 1963 humorous essay entitled "You, too, can speak Gaelic,",[2] reprinted in the anthology Adding a Dimension among others, traces the etymology of each component of the chemical name "para-di-methyl-amino-benz-alde-hyde" (e.g. the syllable "-benz-" ultimately derives from the Arabic lubān jāwī (لبان خاوي, "frankincense from Java"). Asimov points out that the name can be pronounced to the tune of the familiar jig "The Irish Washerwoman", and relates an anecdote in which a receptionist of Irish descent, hearing him singing the syllables thus, mistook them for the original Gaelic words to the jig. This essay inspired Jack Carroll's 1963 filk song "The Chemist's Drinking Song," (NESFA Hymnal Vol. 2 2nd ed. p. 65) set to the tune of that jig, which begins "Paradimethylaminobenzaldehyde, / Sodium citrate, ammonium cyanide, / ..."[3]

See also[edit]

References[edit]

  1. ^ G. W. Watt, J. D. Chrisp (1952). "A spectrophotometric method for determination of hydrazine". Anal. Chem. 24 (12): 2006–2008. doi:10.1021/ac60072a044. 
  2. ^ Asimov, Isaac (March 1963). "You, too, can speak Gaelic". The Magazine of Fantasy and Science Fiction 24 (3): 72–81. 
  3. ^ Carroll, John A. (1963). "The Chemist's Drinking Song". Dagonell's Bardic Notebook. David P. Salley. Retrieved 14 May 2013.