Nachweisreaktionen mit Indikatorstäbchen

„Chemie en miniature”︁ also includes a method for qualitative analysis. A new interpretation of some classical detection reactions for copper, iron, magnesium and nickel ions is given. These reactions take place on a reaction zone of a few mm² on self made test sticks. In order to present these reactions in front of a large audience they are projected onto a screen.     

Über primäre Disazofarbstoffe mit Aminonaphtol-sulfonsäuren

Disazo dyes from 6-amino-1-hydroxy-naphthalene-3-sulfonic acid (J acid) were synthesized by coupling ortho-hydroxy monoazo dyes with different diazonium compounds in acid medium (dyes No 3 – 14 . A second coupling to the ortho position of the amino group was also possible with the copper complexes of o,o' -dihydroxy monoazo dyes from 8-amino-1-hydroxynaphthalene-3,6-disulfonic acid (H acid) dyes No 19 – 22 ). This is a reversal of the well known rule that the formation of disazo dyes with aminonaphthol-sulfonic acids is only practicable when an acid coupling is followed by an alkaline one. 5-Amino-1-hydroxy-naphthalene-3-sulfonic acid (M acid), which is said to form no disazo dyes, could be coupled twice with several diazonium compounds to yield disazo dyes (dyes No 24 , 26 , 27 , 29 ).