||How was the first artificial dye made?
In these activities a Directed Activity Related to
Text (DART) describes the making of mauve, the first artificial
aniline dye, as a setting for organic synthesis. Students compare Perkin’s
original patent with a more modern technique, identifying the compounds
and methods involved.
These activities will work within a series on aromatic chemistry,
providing an historical context for work on reactions of benzene and
developing reaction pathways, as well as exploring practical constraints.
Students will recognise that
- organic synthesis involves a series of steps using set techniques
- mauve was made from ‘coal-tar’, a by-product of the gas industry
- chemical nomenclature has changed as chemists developed greater
understanding of the formulae and structures of the materials they use.
Sequence of activities
||As an introduction, invite students to look at the
colours in the clothes they and you are wearing, or discuss the latest
colour fashions and how these change seasonally. Find out if students
are aware of indigo as an ancient dye still used in producing denim,
using this as a link into looking at the first ever artificial dye to
be made commercially.
Relate their responses to the learning objectives.
||Give each student a copy of the sheet How was
Arrange for students to work individually on the
first two sections, but in pairs or groups for the third section.
Note: students can peer review responses to the first two
||Circulate and support as students work through the
first two sections of the DART.
The most difficult part will be
working out the modern chemical names of the compounds listed in the
procedures. Additional resources will be needed to support this
Ask the students to
- get into groups or pairs.
- review each other’s responses to the first two sections
- discuss answers to the final section, agreeing on responses
- decide who should feedback to the class.
||In a plenary:
- review responses to any contentious aspects of the first two
- check flowcharts for completeness
- check chemical names are correct
- check the reaction pathways for chemical sense
- clarify points to confirm understanding
- review responses to the third section
- draw out relevant points.
- Perkin’s lack of detailed measurements – why was this?
- Use of phrases like ‘sulphate of’ and ‘base enough’ chemical
names were not accurate – why have these changed?
- Small measurements used in the modern process – how are these
- Techniques such as suction filtration, evaporation and
mechanical mixing developed since Perkin’s day. How do techniques
affect the outcomes of chemical procedures?
- Our understanding of structures and formulae has developed
enormously since 1856 (prior to the existence of the Periodic
Table), for example, communication and collaboration between
chemists has developed; and these changes meant we had to
develop systems for naming compounds consistently.
- Perkin can be regarded as the world’s first chemist
involved in synthesis of new organic compounds – an entire branch of
chemistry developed from his work.
||Collect responses for written feedback. Focus on
understanding of chemical nomenclature, reaction pathways and
Assessment for learning commentary
Students work alone, then have their work peer reviewed in pairs or
small groups. This permits development of ideas in a secure way as
students compare their answers to the questions. Group work enables
pooling and sharing of ideas learned through the individual work.
Teacher written feedback supports the development of understanding
about organic synthesis.
For each student
||How was mauve made?
S. Garfield, Mauve: How One Man Invented a Colour That Changed the
World. London: Faber and Faber, 2000.