Understanding Organic Functional Groups: Halides, Alcohols & Ethers

1. Organic Chemistry • Functional Groups • Halogens, Alcohols & Ethers

2. Functional Groups Besides hydrogen or carbon bonded to carbon Many other atoms can bond to carbon and these Lead to the formation of what are called “Functional groups” Each Functional group has it’s own unique chemical And physical properties So what kind of functional groups are there? Check out Table R in your Reference Table.

3. TABLE R – Functional Groups • Halides • Alcohols • Ethers

4. Organic Halides • One or more of the hydrogen atoms in an alkane is replaced with a halogen • F, Cl, Br, or I • Not hydrocarbons! Often called halocarbons.

5. Properties of Alkyl Halides Alkyl halides are extremely unreactive • Often used when chemical inertness • is important • Examples: CFC’s (refrigerants, Aerosol • propellants, Teflon (polymer), Brominated • compounds (Fire retardant clothing) • -many of these compounds are now banned • from use for health and environmental • reasons.

6. Properties of Alkyl Halides • Alkyl halides due to there high molecular wt. have considerably higher B.P. than their corresponding alkanes • Bonds are polar but compounds are not soluble in water • Probably because they can’t form H bonds Is CHCl3 a polar compound? What about CCl4? Yes No

7. c-c-c-c-c Br Br Naming Organic Halides Use prefixes to specify substituent: • fluoro, chloro, bromo, iodo • If more than one, use di, tri, etc. to specify # of substituents. • If necessary, give locations by numbering C-atoms in backbone so that the halide has the lowest number. 2,3-dibromopentane

8. H H H H–C–C–C–H H F H H H–C–Cl H Naming Halides CH3ClCH3CHFCH3 Chloromethane 2-fluoropropane “Chloroform” C3H7F

9. Name the following Compound: CH3CCl2CHClCH3 HCl H H H –C – C – C – C– H HCl ClH 2,2,3-trichlorobutane C4H7Cl3

10. F Cl H-C C-H F Cl Name this compound: 3-Bromo-2-Iodopentane Name this compound: 1,1-dicloro-2,2-difluoroethane One of the “freons”

11. Alcohols • Alcohols contain the polar -OH functional group • OH groups are capable of Hydrogen bonding • This polar functional group affects physical properties • B.P is much higher than the corresponding Alkane • Ethanol (C2H5OH) +78C // Ethane (C2H6) -89C • Low Mol. Wt. Alcohols are very soluble in water

12. Hydroxyl groups Alcohols can hydrogen bond because they have a Hydrogen atom that is bonded to oxygen. This results in Much higher B.P.’s And higher water solubulity CH3–CH2–O-H CH3–CH2–O-H H-O-H

13. Physical properties of Alcohols

14. Naming Alcohols • Select as the parent structure the longest continuous carbon chain that contains the –OH • Drop the –e from the alkane name of the carbon chain and add –ol • Indicate by a number (if necessary) the position of the –OH group ethanol 2-propanol

15. Types of Alcohols • Alcohols are also considered to be either - primary, secondary, or tertiary alcohols • Designations correspond to which carbon atom the –OH group is bonded to - Affects Chemical Reactivity/Properties - Tertiary more reactive than Primary Primary alcohol: OH bonded to –CH20H Secondary alcohol: OH bonded to –CHOH Tertiary alcohol: OH bonded to -COH

16. Types of Alcohols Primary alcohol Secondary Alcohol Tertiary Alcohol

17. Even though ethers have an oxygen atom in their Structure they are unable to form hydrgen bonds with themselves - alkyl groups are bonded directly to Oxygen - No hydrogen bonded to Oxygen Ethers are not linear; They have a bent shape similar to water Ethers

18. Ether’s Properties • BP’s tend to be low • Comparable to similar MW hydrocarbons • No internal H-bonding • Solubility in water is reasonably high for lower M.W. ethers • H-Bonding to Water is possible

19. Name the groups (alkyl) on either side and add ether to the end. List attached alkyl groups in order of increasing size If they are the same the side chain is labeled “Di” NO NUMBERS NEEDED to designate location of Oxygen! Naming Ethers(common names)

20. Naming Ethers Name this compound: Dimethyl ether Name this compound: Ethylpropyl ether