chem / organic.mdon commit perpendicular vector resolute (1e6715b)
   1# Organic Chemistry
   2
   3Organic compounds > 90% of known chemicals
   4Carbon makes living systems possible
   5
   6Carbon forms 4 covalent bonds (4 valence pairs)
   7Strong bonds with other non-metals
   8Bonds with itself with single, double or triple
   9Can form chains or rings
  10
  11Large number of compounds due to:
  12- 4 valence pairs
  13- single / double / triple bonds
  14- cyclic (ring) structures
  15
  16## Hydrocarbons
  17
  18Hydrocarbons - only carbon and hydrogen
  19If all C-C bonds are single, the hydrocarbon is saturated
  20
  21Hydrocarbons
  22- linear (aliphatic)
  23- - saturated (all single C-C bonds)
  24- - - alkane ($C_n H_{2n+2}$)
  25- - unsaturated
  26- - - alkene ($C_n H_{2n}$)
  27- - - alkyne ($C_n H_{2n-2}$)
  28-
  29- cyclic (ring)
  30- - saturated
  31- - - e.g. cyclohexane
  32- - unsaturated
  33- - - e.g. benzene
  34
  35Carbon compounds with 4 branches are tetrahedral
  36
  37Compounds with $C-H$ are insoluble in water
  38These compounds are almost non-polar due to similar electronegativities
  39
  40Only dispersion forces (between electrons on the outside of two molecules) hold each molecule together
  41Dispersion forces increase with size (chain length), therefore MP and BP of straight molecules increases with length
  42
  43Branched molecules have lower MP and BP due to lower density (molecules are further apart due to their shape, so dispersion forces are weaker)
  44
  45Homologous series - formula for molecules (e.g. alkanes, alkenes, alkynes) where each member differs by some increment
  46
  47Structural isomers - same molecular formula, different configuration (structural formula)
  48
  49## Alkanes
  50$$C_n H_{2n+2}$$
  51- Single bonds between carbon atoms
  52- ending in *-ane*
  53
  54methane $CH_4$
  55ethane $C_2H_6$
  56propane $C_3H_8$
  57butane $C_4H_10$
  58pentane $C_5H_12$
  59hexane $C_6H_14$
  60$\dots$
  61
  62Alkanes burn in oxygen forming $CO_2 + H_2O$ (oxidation / combustion reaction)
  63
  64Alkanes react with chlorine or fluorine (substitution reaction) - Cl or F replace H. Result is a haloalkane.
  65
  66## Alkenes
  67
  68$$C_nH_{2n}$$
  69
  70- C-C double bond
  71- ending in *-ene*
  72
  73methene $CH_2$
  74ethene $C_2H_4$
  75propene $C_3H_6$
  76butene $C_4H_8$
  77pentene $C_5H_10$
  78hexene $C_6H_12$
  79$\dots$
  80
  81Alkenes burn in oxygen forming $H_2O + CO_2$.
  82
  83Alkenes react with hydrogen or a halogen (addition reaction) - additive breaks the double bond (catalyst is required).
  84
  85## Alkynes
  86
  87$$C_nH_{2n-2}$$
  88
  89- C-C triple bond
  90- ending in *-yne*
  91
  92Alkynes undergo combustion (oxidation) and addition reactions (same as alkenes).
  93
  94## Rules for naming HCs
  95
  961. Find longest chain of C atoms (incl. branches)
  972. Start at end nearest a branch or double/triple bond
  983. Name carbon atoms from end chosen
  994. Branches end with *-yl*
 1005. When there are $\ge$ 2 branches, number of C atom is indicated before each branch, and names are in alphabetic order.
 1016. When there are $\ge$ 2 identical branches, *di-*, *tri-*, and *tetra-* are used.
 102
 103## Combustion
 104$$C_xH_y+z0_2 \to\ xCO_n+{y \over 2}H_2O$$
 105**Complete**
 106$z=x+{y \over 4}, n=2$
 107
 108**Incomplete**
 109$z={{2x+y} \over 4}, n=1$
 110$z={{x+y} \over 4}, n=0$
 111
 112## Functional groups
 113
 114Atom(s), or a bond, which give a properties to an organic molecule.
 115
 116### Alcohols / hydroxyls
 117
 118- ---OH functional group
 119- ends in *-ol*
 120- alcohols have multiple isomers
 121- combustible with oxygen
 122- BP and MP are affected by H-bonding
 123- **H-bonds are represented by dotted lines**
 124
 125### Carboxylic acids / carboxys
 126
 127- ---COOH functional group
 128- ends in *-oic acid*
 129- first portion of name (e.g. **methan**oic acid) refers to **total** number of carbons
 130- weak acids (proton from O is donated)
 131- high BP
 132
 133### Esters
 134- carboxylic acid reacts with alcohols to form esters (condensation / esterification)
 135- catalyst is $H_2SO_4$
 136- low boiling points
 137- intermolecular bonding is dipole-dipole and dispersion rather than H-bonding
 138- ends in *-oate*