Hydrocarbon Derivatives:

Halocarbons, Alcohols, & Ethers

Hydrocarbons

• Contain only carbon & hydrogen • carbon can also form strong covalent bonds with other elements such as: O, N, F, Cl, Br, I, S, & P

Functional Group

• functional group: atom or group atoms in organic molecule that always behaves the same way • Adding functional group changes chemical & physical properties in specific ways – depends on type functional group added

Intermolecular Forces

• Determine Boiling Point & Solubility • Van der Waals or dispersion: weakest – nonpolar molecules • Dipole-dipole: intermediate strength – molecule has atoms with different electronegativities – atoms not arranged symmetrically • Hydrogen bonding: strongest – molecules contain H bonded to F, O, or N

Functional Groups

1. Halocarbons 2. Alcohols 3. Ether 4. Aldehydes 5. Ketones 6. Carboxylic Acid 7. Ester 8. Amines 9. Amide 10.Amino Acid

Organic Halides

• One (or more) hydrogen atoms in alkane is replaced with halogen atom (F, Cl, Br, or I) • No longer • hydrocarbons! called halocarbons, alkyl halides or organic halides

Naming Halides

• Figure out backbone name • prefixes specify substituent: fluoro, chloro, bromo, iodo • use di, tri, tetra (if more than one same thing) • Give location(s) of halogen(s) – tell # C attached to in backbone

CH 3 Cl H  H–C– Cl H  chloromethane CH 3 CHFCH 3 H H H  H–C–C–C–H H F H  2-fluoropropane C 3 H 7 F

Naming Halides

CH 3 CCl 2 CHClCH 3 H – H Cl H H C – C – C – C – H H Cl Cl H 2,2,3 trichloro butane C 4 H 7 Cl 3

Ranking Halogens

• If more than 1 kind halogen atom present – name them alphabetically • # C’s so lowest number goes to halogen alphabetically first

Different Halogens

4 3 2 1

Chlorine is 1 st numbering: alphabetically, so it determines 2-chloro-4-fluoro-3-iodobutane

Name:

Br CH 3  CH 2  CH  CH  CH 3 I 3-bromo 2-iodo pentane F Cl H  C  C  H F Cl 1,1-dichloro-2,2-difluoroethane

Properties of Halocarbons

• alkane & alkyl halide of similar size & shape: – alkyl halide has higher bp & higher density Why?

Stronger intermolecular forces • CH 4 : bp = -162  C density = 0.423 g/ml • CH 3 Cl: bp = -24  C density = 0.911 g/ml

CH 3 CH 2 CH 2 CH 2 CH 3 pentane CH 3 CH 2 CH 2 CH 2 CH 2 F 1-fluoropentane CH 3 CH 2 CH 2 CH 2 CH 2 Cl 1-chloropentane CH 3 CH 2 CH 2 CH 2 CH 2 Br 1-bromopentane CH 3 CH 2 CH 2 CH 2 CH 2 I 1-iodopentane Boiling Point (  C) 36 63 108 130 155 Density (g/ml) 0.626

Inc 0.791

0.882

1.218

1.516

Inc

Uses of Alkyl Halides

• Cleaners & solvents • Examples: – Teflon & PVC’s – Refrigerants (used to be chlorofluorocarbons- now hydrofluorocarbons)

Halogen Derivatives

• CH 3 Cl = local anesthetic • CHCl 3 = solvent, general anesthetic • CHI 3 = antiseptic • CCl 4 = dry cleaning solvent • CF 2 Cl 2 = refrigerant • Fluorocarbons = teflon, lubricants, synthetic blood • Chlorofluorocarbons = aerosol propellants, refrigerants

Table R

• General Formula halocarbons: R-X – R represents entire hydrocarbon part of molecule – X represents halogen (F, Cl, Br, or I)

Alcohols

• • OH group replaces H in hydrocarbon OH group called: hydroxyl group H  H C H    H OH H  H C   OH H 

Alcohols are

non

electrolytes!

• hydroxyl group = hydroxide ion of inorganic bases - does not form ions in water!

• hydroxyl group is polar – alcohols soluble in water

Naming Alcoh

OL

s

• Based on alkane name • Name parent chain – Drop the –e and add – ol • If parent chain has 3 + C’s, # which C OH group(s) attached to

Naming

H H H H H  C  C  C  C  H OH H H H H H H H H  C  C  C  C  H H OH H H 1-Butanol bp = 100  C 2-Butanol Bp = 115  C Note: Never more than one OH group per C

More than 1 hydroxyl group

• Prefixes di-, tri-, tetra- used before ending tell # of hydroxyl groups ol

Classifying Alcohols

• By # of hydroxyl groups –Monohydroxy: 1 hydroxyl group –Dihydroxy: 2 OH groups –Trihydroxy: 3 OH groups • By position of each hydroxyl group on main carbon chain

Monohydroxy Alcohols

• Primary : hydroxyl group attached to end C of chain or branch • Secondary : hydroxyl group attached to C in chain bonded to 2 other C’s • Tertiary : hydroxyl group attached to C at a branch point (C bonded to 3 other C’s)

H H H H H-C-C-C-C O-H H H H H H H H H H-C-C-C-C-H H H O H H 1-butanol (primary) 2-butanol (secondary)

H-C-H H H 2 H-C-C-C-H H H O H H 2-methyl 2-propanol (Tertiary)

H H H-C─C-H O O H H Dihydroxy H H H H-C─C─C-H O O O H H H Trihydroxy

Properties of Alcohols

• Contain: H bonded to O atom – Hydrogen Bonding • Alcohols have higher bp corresponding alkane than • ‘Like dissolves Like’ – Alcohols tend to be very soluble in water

R H  + O  H-bond R H  + O  -

Which compound has the highest boiling point?

A. CH 4 B. C 2 H 6 C. C 3 H 8 D. C 3 H 7 OH Correct response = D

Table R

• General Formula Alcohols: R  OH • R represents entire hydrocarbon part of molecule • OH is hydroxyl group

Ethers

• General formula R  O  R  – where R  may or may not be same as R • R and R  are hydrocarbon branches • O is oxygen bridge • Ethers are not linear – they are bent, like water

Properties of Ethers

• Pure ether: no hydrogen bonding – weak dipole-dipole interactions – bent, like H 2 O • Ethyl ether once used as anesthesia

Properties of Ethers

• Compared to alkanes (same # C’s): – Higher bp’s than similar alkanes – More soluble in water than alkanes • Compared to alcohols (same # C’s): – Lower bp’s than similar alcohols – Much less soluble in water than alcohols

Naming Ethers

• If both hydrocarbon branches are identical: – name the branch (once) & add the word ether • If 2 branches are different: – list them in alphabetical order followed by the word ether

H H H  C  O  C  H H H Methyl Ether H H H H H H H  C  C  C  O  C  C  C  H H H H H H H Propyl Ether

H H H H H  C  O  C  C  C  H H H H H Methylpropyl Ether