INTRO CHEMISTRY I

CHEM 1405

ORGANIC CHEMISTRY

ORGANIC CHEMISTRY

Organic Chemistry - the chemistry of most compounds of carbon. Organic chemistry is a major division because of the possibility of multiple carbon arrangements in organic compounds.  Almost all known organic compounds   contain hydrogen.

The major source of the raw materials for industrial organic chemicals is the fossil fuels.

Organic chemistry is very dependent on structural theory.  By knowing the structure of a compound, we can predict physical properties (boiling and melting points, etc) and chemical behavior (reactions, solvents, etc).

COVALENCE NUMBERS

Covalence numbers are the number of bonds an element will typically form.  Covalence numbers (the number of bonds) are used to draw the structures of organic compounds and determine molecular formulas.

C = 4  (CH4)

N = 3  (NH3)

H = 1  (HBr)

O and S = 2  (H2S and H2O

Halogens = 1  (HBr)

For example, carbon normally forms four bonds with other compounds (CH4) while hydrogen only forms one bond.

HYDROCARBONS

Hydrocarbons contain hydrogen (H) and carbon (C).

CLASSIFICATION BY STRUCTURE: THE FAMILY

Structural theory relies on the structures of the molecules. These structures are divided into families.

ALKANES

Alkanes are hydrocarbons which only contain single bonds between carbons. Alkanes are also referred to as paraffin or saturated hydrocarbons.

Structure formulas show how the atoms are bonded to each other.  Below is called a full structural formulas.

Formulas can also be written in a condensed form:

or in a skeleton form:

ALKANE SERIES

 

ALKANES

ALKYLS

methane

CH4

methyl

CH3

ethane

C2H6

ethyl

C2H5

propane

C3H8

propyl

C3H7

butane

C4H10

butyl

C4H9

pentane

C5H12

pentyl

C5H11

hexane

C6H14

hexyl

C6H13

heptane

C7H16

heptyl

C7H15

octane

C8H18

octyl

C8H17

nonane

C9H20

nonyl

C9H19

decane

C10H22

decyl

C10H21

-ane at the end of the name indicates the compound is an alkane

-yl indicates that the alkane is short one hydrogen and is a fragment that will attach to something else.

ISOMERS

Isomers are compounds with the same molecular formula but different structures.

The two structures below both have a molecular structure of C5H12 but they have different structures.  One is straight and the other is branched.

CYCLIC HYDROCARBONS - rings

Alkanes can also be arranged into a ring.  These are called cycloalkanes.  Sometimes a geometric pattern is used in place of the actual carbons.  The compound below would be called cyclopropane since it is in a ring and only has 3 carbons.

UNSATURATED HYDROCARBONS

Unsaturated hydrocarbons have some carbon - carbon bonds that are multiple bonds: two or three pairs of electrons (bonds) between carbon atoms.

Compounds that have double bonds are called alkenes and most alkenes end with -ene.

Compounds that have triple bonds are called alkynes and most alkynes end with -yne.

AROMATIC HYDROCARBONS

Benzene is the principle structure of all aromatics compounds.  Benzene is a ring structure with 6-carbons and 6-hydrogens and three double bonds.  The structure can be drawn three ways.

Aromatic compounds contain the benzene ring as part of their structure.

CHLORINATED HYDROCARBONS (contain Cl)

Chlorinated hydrocarbons contain hydrogen, carbon, and chlorine.

CH2Cl2 methylene chloride

(solvent, paint remover, etc)
CH3Cl methyl chloride (silcon polymers)
CHCl3 chloroform (anesthesia)
DDT   (pesticide)

CHLOROFLUORCARBONS and FLUOROCARBONS (CFC)

Chlorofluor and fluorocarbons contain either fluorine or fluorine and chlorines.  They are used as aerosol gases in spray cans, to make foam plastics, and refrigerants.

Teflon is an example of a fluorocarbon:

FUNCTIONAL GROUPS

Functional groups are unique structural components that a similar within a family of organic molecules. An "R" in a structure represents an string of carbons.

ALCOHOLS  (R-OH)

All alcohols have a characteristic -OH attached to a carbon.  All alcohols have names ending in -ol or the word alcohol.

methanol = methyl alcohol = wood alcohol = CH3OH (solvent and chemical intermediate)

ethanol = ethyl alcohol = grain alcohol = C2H5OH (solvent and chemical intermediate)

Denatured ethyl alcohol is ethanol made chemically unfit to drink.

1 percent alcohol is the equivalent of 2-proof.  Example: 100 proof rum is actually 50% alcohol.

isopropyl alcohol = rubbing alcohol

ethylene glycol = antifreeze (toxic)

propylene glycol = antifreeze used for foods and medicines - not toxic)

glycerol = glycerin (lotions, explosives, food additive to keep cake moist)

phenol (first antiseptic - 1867)

ETHERS (R-O-R)

Common ethers have names ending in "ether"

diethyl ether (first anesthetic 1847 - solvent)     C-C-O-C-C

methyl t-butyl ether (MTBE - antiknock for gasoline)

ethylene oxide (used to make antifreeze and to sterilize medical instruments)

ALDEHYDES   ( )

Names of aldehydes end in either -al or the word aldehyde.

Formaldehyde = methanal  (a gas at room temperature normally used in labs in which the gas is a 40% solution of formaldehyde in methanol which is called formalin.  Industrially used to make plastics.)

KETONES (  )

Names of ketones end in either -one or the word ketone.

   acetone = propanone (solvent, paint remover)

     ethyl methy ketone (MEK - degreaser)

CARBOXYLIC ACIDS   (    or   )

The names of carboxylic acids end in either -ic acids or -oic acid.  Carboxylic acids are weak acids.

The common names of carboxylic acids are derived from their original source. Smaller carboxylic acids have sharp pungent unpleasant orors.

   formic acid (latin for ant) = methanoic acid (ant bites and warp, bee stings)

    acetic acid = ethanoic acid (5% vinegar)

   butyric acid (latin for butter) = butanoic acid (rancid butter and body odor)

  benzoic acid

sodium benzoate (derived from benzoic acid used as a food additive to prevent mold)

ESTER ( )

The names of ester end in -ate or the word ester.  Many esters are fragrant and have fruity odors.  Are used in a artificial flavors.

AMINES  ( )

Amines end in the word amine or has the word amino in the name.  Amines often have the odor of ammonia from which many are derived.  Amines are organic bases.

   aniline  (aromatic amines are toxic and carcinogenic - used to make dyes)

   amphetamine

   cadaverine

       amino acids (found in proteins)

AMIDES  ( )

Amide normally have the word amide in the name.  Amides are found in proteins and manmade polymers.

   urea

HETEROCYCLIC COMPOUNDS

Heterocyclic compounds are rings with atoms other than carbon within the ring structure.  Some of the more common heterocyclics are alkaloids (bitter taste) that include morphine, caffeine, nicotine and cocaine and the bases of nucleic acids which are a structural feature of DNA and RNA.

  pyrimidine

 

  purine