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Halogenated Hydrocarbons and Addition Polymers

Halogenated Hydrocarbons and Addition Polymers. Halogenated Hydrocarbons. Halogens want to form 1 bond like H Can substitute directly for H on HC’s Many used to form plastics (polymers) Examples Methyl bromide Natural in the oceans Sterilizes soil Damages the ozone layer.

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Halogenated Hydrocarbons and Addition Polymers

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  1. Halogenated Hydrocarbonsand Addition Polymers

  2. Halogenated Hydrocarbons • Halogens want to form 1 bond like H • Can substitute directly for H on HC’s • Many used to form plastics (polymers) • Examples • Methyl bromide • Natural in the oceans • Sterilizes soil • Damages the ozone layer

  3. Chlorinated Methanes • Methylene Chloride (dichloromethane) • Volatile liquid – common solvent • Used to extract caffeine from coffee beans • Possible carcinogenic • Chloroform (trichloromethane) • Volatile liquid – common solvent • First medical anesthetic • Carbon tetrachloride – solvent – fire extinguisher – no longer used

  4. CFC’s • Chlorofluorocarbons or freons • All methane hydrogens replaced • Very unreactive • Boiling points below room temperatures • Used for air conditioning and refrigerators • May damage the ozone layer

  5. Chlorinated Ethenes • Vinyl chloride (chloroethene) • Starting point for common plastics • Carcinogen • Trichloroethene, TCE • Very stable solvent – not used much • Tetrachloroethene, PCE • Dry cleaning solvent • Common water pollutant

  6. Plastics • Flows under heat and pressure • All plastics are polymers • Not all polymers are plastics • Very prominent in our lives • 24 of top 50 chemicals used for polymers • Rising labor costs • Dwindling resources • Better properties

  7. Synthetic Polymers • Involved in 80% of organic chemical industry • Since 1976 US has produced more polymers than steel • More than 200 lbs per person per year

  8. Synthetic Polymers • Some copy nature: • Rayon ↔ cellulose • Synthetic rubber ↔ natural rubber • Nylon ↔ protein • Many more don’t: • Polystyrene, Dacron, Teflon, Kevlar, polyesters

  9. Polymers • There are many polymers in nature – life • Proteins, starch, DNA, RNA, silk, wool, cotton • Herman Staudinger – 1920’s • Coined word “macromolecules” • Polymer comes from • Poly – many • Mer – parts • Polystyrene – one of first synthetic polymers • Why?

  10. Addition Polymers • Monomers must have C=C as in styrene • Monomers are all derivatives of ethene (ethylene) • Simplest is polyethylene –CH2(-CH2-CH2)n-CH2- • Molecular weight ~ 1 million g/mole • Branched – LDPE – sandwich bags – soft • Linear – HDPE – milk jugs – hard – tough • X-linked – CLPE – soft drink bottle caps – very rigid

  11. H13 – C5 • 1, 3 - 6, 9 - 15, 18, 27, 50, 51, 53, 54, 62, 63, 70, TiF-Ex’s 5.8, 5.9

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