ORGANIC CHEMISTRY

Definitions
Organic chemistry - study of carbon-containing compounds
Hydrocarbons - compounds made of only carbon and hydrogen
Biochemistry - organic chemistry involved in life processes

Bonding
(1) Single bond                                     H
                                                        H-C-H
                                                            H
                                            Each - represents 2 electrons

(2) Double Bond                         H-C=C-H
                                                        H H
Double and triple bonds are referred to as "unsaturated"

(3) Triple Bond                         H-C/ C-H         2 single bonds between C-H

Formulas
(1) Molecular formula-number and kinds of atoms, but no idea what it looks
like C4H10

Structural formula - order of attachment of atoms in a molecule.
        H H H H
    H-C-C-C-C-H                 CH3CH2CH2CH3
        H H H H                 Condensed structural formula
expanded structural formula

Dimensional formula - geometry stressed

ALKANES

Single Bonds
Paraffins

Types of Alkanes
Straight Chain                                 H H
                                                  H-C-C-H             CH3CH3 or C2H6
                                                      H H

                                                      H H
Cyclic                                         HC - CH
                                                      |     |
                                                  HC - CH
                                                     H   H
 


Branched                             C- C- C- C-C- C
                                                       |     |
                                                      C   C

Nomenclature
CH4 - methane                                                     C6H14 - Hex__________

C2H6 - ethane                                                     C7H16 - Hept_________

C3H8 - propane C8H18 - _____________

C4H10 - butane C9H20 - non__________

C5H12 - pentane C10H22 - dec_________

AlkANES end in ANE

Look at the numbers:
1,4; 2,6 ;3,8; 4,10; 5,12; 6,____; 7,_____

CnH2n+2 - general formula for alkanes
How many hydrogens are there in the alkane having 22 carbons?

CH4 - natural gas                                         C2H6 - also in natural gas
C3H8 - heating gas                                        C4H10 - heating
pet ethers - C5 C6                                        C7 mixture - solvent
alkanes 4 to 12                                             heating oils
lubricating oils                                               waxes
C12 C15                                                        C15Oils - C20
Waxes - C26-C30                                         straight chain

normal octane - straight chain                         C-C-C-C-C-C-C-C
branched chain                             C
                                                     |
                                                C-C-C-C-C
                                                     |    |
                                                    C  C


Names
methyl CH3                                 C
ethyl    C2H5                                |
propyl C3H7              C-C-C-C-C-C-C
           C4H9
                                                3-methyl heptane
                    C
                     |
            C C C C C C C         3,3 dimethyl heptane
                     |
                    C
Having the same molecular formula but different structural formulas

-isooctane

Isomers
the longest straight chain (you can count around corners)
groups on the chain
              C
               |
(a) C-C-C-C-C-C                 ________________________ hexane

              C C
               |   |
(b) C-C-C-C-C-C                 ________________________ hexane

              C
               |
(c) C-C-C-C-C
               |
              C - C                     _________________________


Drill
(1) n-pentane

(2) cyclopentane

(3) 2-methyl propane


(4) 3,3 dimethyl pentane

Name

(1) C-C
      |    |
C-C C-C
      |    |
 C-C C-C                     ________________________________

(4)             C-C
                  |
C-C-C-C-C-C
          |
         C                         ________________________________

Reactions of Alkanes
although generally unreactive, these reactions do occur
1. Halogenation
                              Ultraviolet
                                light
    CH4 + CCl2 ------> CH3Cl + CH2Cl2 + CHCl3 + CCl4 + HCl

2. Combustion burning in oxygen
                        spark    
    CH4 + 2O2 ------> CO2 + 2H2O + energy

Alkenes
Alkenes and in ENE
Have one or more double bonds

            C-C=C-C butene

Formula for alkenes Why? 2 hydrogens are replaced by a double bond.
CnH2n

Where can the double bond be?
C=C-C-C-C                 1-pentene
C-C=C-C-C                 2-pentene
C-C-C=C-C                 _________
C-C-C-C=C                 _________

2 double bonds - called diene
3 double bonds - called triene

Samples
CH2=CH-CH=CH2

4 carbons buta
2 double bonds butadiene
Where are the = located 1,3-butadiene

Name
(1) C-C=C-C=C-C-C-C-C

(2) C-C=C-C=C-C=C-C-C

(3) C-C-C-C-C-C-C-C
                        |
                       C=C

Which is the parent chain of #3? 8 C alkane or 7C alkene? Ans: Alkene

Isomers
C-C              Carbons can turn in a single bond (sigma bond).

C=C             Carbons can't turn in a double bond so we get isomers (pi bond).

Cis - same side
Cl   Cl                            Cl   H
C - C                             C - C
H    H                             H   Cl
                                      Trans - across - opposite

trans have to have at least 2 different groups on the carbon atom

Reactions of Alkenes
Hydrogenation
        H     H            H        H
         |       |              |          |
        C = C ------> H C - C H
        H    H     H    H
ethene or ethylene

Animal fats are solid. The vegetable fats (oils) are liquid. Crisco in the can is solid but is made with vegetable oils. To make it solid, the oils are hy

Halogenation
                                                             Br Br
            H-C=C-H + Br2 ----------> H-C-C-H
                H   H                                     H H
Oxidation
(1) mild oxidation - alcohol OH
(2) strong oxidation - acid COOH

Polymerization
(1)
        H2C=CH2 -----------------------> -(CH2CH2CH2CH2CH2CH2)n

ethene or ethylene Polyethylene

(2)
        H    H                                     H   H    H   H    H   H
        C=CH -------------------> -(C - C - C - C - C - C-)
        H   Cl                                     H   Cl    H   Cl   H   Cl
    vinyl chloride                                   Polyvinyl Chloride
                                                                    PVC


(3)    H H                             H    H   H    H   H    H
        C=C ---------------> -C - C - C - C - C - C
        H F                             H   F   H    F   H   F
Styrene Polystyrene (styrofoam)

benzene ring F


ALKYNES

Presence of triple bond
Ending in 'yne'
HC         CH             ethyne or actylene
H3CC     CCH3 2-butyne         Triple bond very reactive

ORGANO HALIDES
Halides are the halogens Cl, F, Br, I
(a) Chain-straight, branched or cyclic - alkyl halide
(b) Aromatic ring (benzene) Aryl Halide
      Naturally occurring halogen compounds
      thyroxin
      chloroform CHCl3

Nomenclature
(a) find longest chain - parent - then give position of halogen
                    H   Cl H H
            H-C-C- C-C-H             2-chlorobutane
                    H    H H H

(b) sometimes use "ide"
            CH3Br methylbromide
            CH3CH2Cl ethyl chloride

Important halogenated hydrocarbons
            *(1) chloroform CHCl3
            *(2) carbon tetrachloride CCl4
            (3) freon CCl3F CCl2F2 C2F4Cl2
            (4) Vinyl chloride C2H3Cl
            (5) DDT dichlorodiphenyltrichlorethane

Reactions of halides
            Substitution
                CH3CH2Br + Na (OH)- -----> CH3CH2OH + NaBr-

                CH3CH2Br + H2O -----> CH3CH2OH + HBr-


AROMATIC RING STRUCTURES

Called aryl for aromatic. (Aroma - odor) Non-ring compounds are called alkyl.

Have a ring structure with double bonds.

Benzene

Benzene - a 6 carbon ring with alternating double bonds C6H6

When one hydrogen of a benzene ring is replaced by an element or ring, the ring is called phenyl (C6H5) or benzyl (C6H5). Phenylalanine = amino acid Benzyl oxide = zits medicine

Toluene also called methyl benzene Phenol

 

Naming ring structures (o,m,p order me pizza)
            ortho - two groups are adjacent
            meta - a carbon is between the groups
            para - two carbons are between the groups

Ortho                                                 Meta                                                 Para

1,2-dichlorobenzene                     1,3-dichlorobenzene                     1,4-dichlorobenzene

Naphthalene - two rings joined together
Anthracene - three rings joined together also known as PAH polyaromatic hydrocarbons.

 

Monday, February 04, 2008 11:17:46 AM