Aromatic compounds - PowerPoint PPT Presentation

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Aromatic compounds

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  1. Aromatic compounds Benzene

  2. Objectives

  3. What are they?

  4. Knowing what you know • Try to draw the atomic structure of Benzene C6H6. Think about the number of bonds each carbon atom has!

  5. Actual representations

  6. Trienes • Originally a scientist called Kekule suggested this structure for the benzene ring This is referred to as a triene Why?

  7. But • Benzene and chemicals made from benzene rings joined together (conjugated) such as Naphthalene are much more stable than you’d predict. • At the time Kekule could not have explained this as electrons were not known

  8. Modern representation After Robinson 1947 Referred to as cyclic conjugation In effect 6 πelectrons fly round the middle making it a very stable structure.

  9. Stability of Benzene

  10. Substitution

  11. Derivatives of Benzene (Learn these)

  12. More derivatives of benzene

  13. Benzene rings can be joined • By single bonds such as biphenyl:

  14. Or fused together: Polyaromatic hydrocarbons

  15. Physical properties Like other hydrocarbons they are:

  16. Aromaticsresearch: themes

  17. Produce a scientific poster containingthefollowing:

  18. Marks • 20 marks per chemical (1 aromatic and 1 polyaromatic) • 10 marksfortheproduction of fiveclearunambiguousquestionsbasedonyour poster • Chemicaldividedintofivethemes, eachworth 4 marks. • 4= outstanding • 3 = good • 2 = satisfactory • 1 = poor • Total out of 50. • Good posters to be displayed in school.