Carbon chemistry

• Scheikunde
• Middelbare school
• vwo
• Leerjaar 4,5

Koolstofchemie 4-VWO

Carbon Chemistry

• Hydrocarbon structures

• Functional groups
• Esters/Amides
  
  
• (Lewis Structures)
• (Reaction mechanisms)
• (Biochem)

Hydrocarbon structures

"Saturation" (Alkanes/Alkenes/Alkynes)

Cycloalkanes/Aromatics

Branching

Isomerism

Saturation

• Refers to "hydrogen saturation": A saturated hydrocarbon (an alkane) only has single bonds between carbon atoms. 
• In an unsaturated hydrocarbon there may be double or even triple bonds (resp. an alkene(6.4a) of an alkyne(6.4b)).
• 
  

Homologous series

• Alkanes, Alkenes and alkynes are examples of homologous series. These can be described by an arithmetic relationship between the atoms in the molecule.
• Alkane: CnH2n+2
• Alkene: CnH2n
• Alkene: CnH2n-2
• There are others besides these...

Branching

• A hydrocarbon is branched if at least one C atom is connected to 3 or 4 other C atoms.
• The 2 hydrocarbons on the right have the same molecular formule (C4H10), but very different structures (in this particular case due to branching)
• These 2 molecules are isomers: same molecular formula, different structures.

Cyclic structures

• A closed loop of C atoms.
• The 2 structures shown are isomers (both C4H8), where the bottom one is branched.

Aromatics

• Cyclic hydrocarbons with a benzene structure in them (C6H6) are called aromatic 
• Hydrocarbons without a benzene ring are called aliphatic.

Nomenclature: How to name them?

Stappenplan:

1. Find and name the longest uninterrupted carbon chain. This is the "stem" (main chain).
2. (Find and name the side groups.)
3. Give these groups their numbers (by position) and give them Greek numerals (by frequency).

Use Binas table 66C+D.

Naming alkanes

• Name = stem + ane
  
• General formule: C_nH_2n+2

Naming alkenes

• Name = stem + ene
• General formule: C_nH_2n (for 1 double bond)
• e.g. but-1-ene (but = 4C, 1-ene = double bond on C1).

NAMES:

ethene

propene

but-1-ene

but-2-ene

Multiple double bonds

Name: stem+diene (or triene, or...)

buta-1,3-diene

Alkyl groups

• A side chain with only C atoms is called an alkyl group.
• Naming is similar to alkanes, just -yl instead of -ane
• 
  
• e.g.: methylbutane.
• Why not 2-methylbutane?

Multiple alkyl groups

• Again, just as before, we use Greek numerals (di, tri, etc.).
• 
  
• e.g.: 2,3-dimethylpentane.

Several different alkyl groups

• Name the side groups alphabetically, ignoring the Greek numerals.
  
• 
  
• e.g.: 2-methyl-3-ethylpentane.
• Note that there is always a dash (-)
  between a number and a letter!

What's the name of this little monster? 

(I like to call him "Sulley")

Use BINAS 66C!

1. stem = longest chain = 9 C , nonane
     
2. 2x ethyl = diethyl, 3x methyl = trimethyl
    
3. Lowest possible numbers for positions: 33567 < 34577
    
4. names in alphabetical order:
   3,7-diethyl-3,5,6-trimethylnonane

1

2

3

4

5

6

7

8

9

Functional groups

Halogenalkanes

Alkanoles/alkane amines

Aldehydes/Ketones

Alkanoic acids

Esters/Amides

Halogenalkanes

• Halogen atoms can be side groups.
• Halogens: bromine (Br), iodine (I), chlorine (Cl), fluorine (F).
  
  
• e.g. tetrachloromethane ("tetra", for short)

Examples

2,2-dichloropropane

1,1,1,2-tetrachloroethane

alkanols (-ol)

• O-H side group
• Either hydroxy- or -ol, depending on group priority
  (Binas 66D)

Ethanol

Amine

NH2 side group

Either amino- or -amine, depending on priority

E.g.          propane-1-amine 

Aldehyde (-al)

• C=O group
• An aldehyde always has C=O at the end of a chain
  

Ketone (-one)

• C=O group
  
• A ketone always has C=O somewhere in the middle of a chain
  

Alkanoic acids

An organic acid has this group: 

• An acid is often at the end of a chain,e.g. in butanoic acid,
• The C of the acid group is part of the chain!
• Molecular formula: C3H7COOH

4           3            2            1

Esters

Esters are formed by reacting alkanols with alkanoic acids

Esters

• An ester is formed by a condensation reaction of an alcohol group with an acidgroup, which also releases water.
• The reverse reaction is hydrolysis: An ester can be split up using water.
• Many fruity fragrances and flavourings are esters!
• E.g. methylbutanoate is strawberry

                                    

Condensation

Hydrolysis

 

+ H2O   

                                           +