Organic

General Information-

Organic chemistry is the chemistry of compounds based on the element carbon. There are thousands of these compounds. Carbon compounds can be composed of several hundred carbon. These can be classified into many different groups. The diverse carbon compounds can be formed because: 1. carbon has four valence electrons; 2. carbon can form single, double and triple bonds; and 3. carbon can form an array of bonds with itself. When drawing organic structures, it is helpful to remember that carbon must have four bonds, hydrogen must have only one bond, oxygen must have two bonds, and nitrogen must have three bonds.

Many carbon groups differ from the previous and the succeeding member by some repeating unit, such as CH₂. These are called homologous series and general trends in chemical and physical properties can be found.

Carbon compounds are also characterized by isomerism. Isomers are compounds with the same formula but a different structure. There are different kinds of isomers: structural (different way to draw connecting carbons); geometric (functional or radical groups on the opposite, trans-, or the same, cis-, side of a double or triple bond); optical (can have the same properties but rotate polarized light in different directions, one rotates it the left and the other rotates it to the right, like glucose is levorotatory to the left and dextrose is dextrorotatory to the right, these are mirror images of each other); positional (when a functional group can occupy two or more positions); and functional (a nonhydrogen or noncarbon element is bonded in different).

Carbon compound formulas can be written in several different ways. A molecular formula only shows how many atoms of each element are present. A carbon skeleton shows only the relationship between the carbons and other nonhydrogen elements. A structural formula shows how many and where and how all the atoms of the elements are arranged. A condensed structural formula is and expanded molecular formula but a condensed version of the structural formula showing all the atoms but not exactly where and how they are arranged.

molecular formula structural formula condensed structural formula

or

Carbon compounds are generally named based on the number of carbons present in the parent chain. The parent chain is the longest carbon chain which contains the functional group or has the functional group attached to it. After the first four, the base, or parent, name comes from the Greek or Latin prefixes representing the number of carbons.

A substituent or side chain, is a group attached to the parent chain. This can be a hydrocarbon radical or a functional group. A hydrocarbon radical is formed when one hydrogen is removed from a hydrocarbon, -yl is added to the base name. Hydrocarbon radicals are represented by R, R', or R", etc. A functional group is a nonhydrogen part which increases the reactivity of the hydrocarbon. More than one functional group in a compound has an inductive effect. An inductive effect is the effect one functional group has on another. Many carbon compounds contain several radicals and more than one functional group.

number of carbons:		radical formed:
	meth = 1		methyl
	eth = 2		ethyl
	prop = 3		propyl
	but = 4		butyl
	pent = 5		pentyl
	hex = 6		hexyl
	hept = 7		heptyl
	oct = 8		octyl
	non = 9		nonyl
	dec = 10		decyl
	*benzene = 6		*phenyl

Hydrocarbons – largest group, contain only carbon and hydrogen.

I. Aliphatic – carbons joined in straight, branching chains

A. Alkanes

1. single bonds between carbons, called saturated

2. general formula: C_nH_2n+2

3. naming

a. longest carbon chain is parent chain = base name, ends in – ane

b. number the carbons so the side chains are attached to the lowest numbered carbon possible

c. indicate the number of the carbon that the side chain is attached : hyphen : side chain name

d. name side chains in alphabetical order of the side chain name, if more than one of a particular kind use di–, tri–, tetra–, etc. with carbon numbers separated by commas

4. example: named: 3-ethyl-2,4-dimethylhexane

CH₃ CH₃

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CH₃CHCHCHCH₂CH₃

|

CH₂CH₃

B. Alkenes

1. double bond between carbons, called unsaturated (also called olefins)

2. a double bond is stronger and less flexible than a single bond but more reactive

3. general formula: C_nH_2n

4. naming: same as alkanes except

a. ends in – ene

b. number carbons so the carbon where the double bond starts has the lowest carbon number possible, the number goes between the side chain names and the base name

c. if more than one double bond, use -adiene, -atriene, etc.

5. example: named: 4-ethyl-3,5-dimethyl-2-hexene

CH₃ CH₃

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CH₃CHCHC=CHCH₃

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CH₂CH₃

6. common names: ethylene (ethene) and propylene (propene)

C. Alkynes

1. triple bond between carbons, called unsaturated

2. a triple bond is stronger and less flexible than a double bond but more reactive

3. general formula: C_nH_2n–2

4. naming: same as alkanes except

a. ends in – yne

b. number carbons so the carbon where the triple bond starts has the lowest number possible, the number goes between the side chain names and the base name

c. if more than one triple bond, use -adiyne, -atriyne, etc.

5. example: named: 4-ethyl-3,5-dimethyl-1-hexyne

CH₃ CH₃

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CH₃CHCHCHC=CH

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CH₂CH₃

6. common names: acetylene (ethyne)

D. Alkenes and Alkynes

1. when double and triple bonds are present in the same compound, the ending becomes - enyne, -adienyne, -enediyne, etc.

2. number carbons so the carbons where the double and triple bonds start has the lowest number possible; if there is a choice, the double bond gets the lowest number

3. example: HC=CCH=CHCH=CH named: 1,3-hexadien-5-yne

II. Cyclic – carbons joined in rings

A. Cyclo –

1. regular geometric shapes

2. base name corresponds to number of carbons in ring

3. add cyclo– to front of base name

4. indicate side chains with lowest carbon numbers possible, in alphabetical order

5. double or triple bonds within a ring are numbered as lowest carbon

6. a stylized representation of cyclic compounds is to use the geometric shape

7. example: named: 1,2-dimethylcyclobutane

CH₂–CHCH₃

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CH₂–CHCH₃

B. Aromatic

1. based on benzene (1,3,5-tricylohexene: a hexagon with alternating double bonds)

2. formula: C₆H₆

3. represented as a regular hexagon with a ring inside or as

a regular hexagon with alternating double lines

4. name with groups on lowest number carbon possible and side chain names with benzene, in alphabetical order

5. example: a. named: 1,4-dimethylbenzene

CH₃

CH₃

b. when benzene is used as the radical, it is named as phenyl attached to a chain

named: 2-phenylhexane

CHCH₂CH₂CH₂CH₃

|

CH₃

6. common names: toluene (methylbenzene)

Halogen Derivatives

1. have a halogen attached, such as F, Cl, Br, or I

2. named as fluoro-, chloro-, bromo-, and iodo-.

3. name with functional groups on lowest carbon number possible

4. side chains follow the numbering of carbons established by the halogen functional group, in alphabetical order

5. example: named: 1-bromo-5-chloro-4-fluorohexane

Cl Br

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CH₃CHCHCH₂CH₂CH₂

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F

6. common names: chloroform (trichloromethane), carbon tetrachloride (tetrachloromethane), teflon (tetrafluoroethene), and CFC's or chlorofluorocarbons such as freon (dichlorodifluoromethane)

Oxygen Derivatives

I. Alcohol

A. have hydroxyl group ( –OH )

B. general formula: R – OH

C. naming: named like alkanes except

1. add –ol to base name ending

2. carbon with hydroxyl group must have lowest number possible

3. side chains follow the numbering of carbons established by the hydroxyl functional group, in alphabetical order

4. examples: a. benzene with a hydroxyl group is called phenol

b. named: 4,5-dimethyl-2-hexanol

CH₃ OH

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CH₃CHCHCH₂CHCH₃

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CH₃

5. common names: isopropyl or rubbing alcohol (2-propanol), ethyl alcohol (ethanol), ethylene glycol (1,2-ethanediol), glycerol (1,2,3-propanediol), hexylresorcinol (4-hexyl- 1,3-phenediol), Lysol^® or cresol (3-methyl-1-phenol), and oil of roses (2-phenylethanol)

II. Ether

A. have an oxygen in between two carbons

B. general formula: R – O – R'

C. naming

1. name shortest chain first, without an ending

2. name longer chain as normal

3. join the two names by placing an – oxy – between them

4. example: CH₃–O–CH₂CH₂CH₂CH₂CH₂CH₃

named: methoxyhexane

5. common names: diethyl ether (ethoxyethane) and methyl phenyl ether (methoxybenzene)

III. Aldehyde

A. carbonyl group, a double bonded oxygen that is always on the first carbon O

^{| |}

B. general formula: R – C – H OR R – CHO

C. naming: named like alkanes except

1. add –al to end of base name

2. side chains are named from the carbonyl first carbon, in alphabetical order

CH₃ O

^{| | |}

3. example: CH₃CHCH₂CH₂CH₂CH named: 5-methyl-hexanal

4. common names: formaldehyde (methanal), acetylaldehyde (ethanal), and benzaldehyde (benzene with a carbonyl attached or phenylmethanal)

IV. Ketone

A. carbonyl group but not on the first carbon in a chain

O

^{| |}

B. general formula: R – C – R'

C. naming: named like alkanes except

1. add –one to end of base name

2. carbon with carbonyl group must have lowest number possible

3. side chains follow the numbering of carbons established by the carbonyl functional group, in alphabetical order

CH₃ O

^{| | |}

4. example: CH₃CHCH₂CCH₂CH₃

named: 5-methyl-3-hexanone

5. common names: acetone or dimethyl ketone (2-propanone), MEK or methylethyl ketone (2-butanone), acetophenone or methyl phenyl ketone (1-phenyl-1-ethanone), testosterone, and progesterone

V. Organic Acids

A. carboxyl group: comes from carbonyl and hydroxyl on the same carbon and it is always the first carbon in a chain

B. many organic acids are found in foods (benzoic: cranberries; tartaric: grapes; citric: citrus fruits; lactic: sour milk; oxalic: rhubarb; malic: green apples; and acetic: vinegar), acids with higher carbon numbers have unpleasant odors

O

^{| |}

C. general formula: R – C – OH OR R – COOH

D. naming: named like alkanes except

1. add –oic acid to ending of base name

2. side chains are named from the carboxyl first carbon, in alphabetical order

3. some acids have a carboxyl group on each end of the compound

CH₃ CH₃ O

^{| | | |}

3. example: CH₃CHCH₂CHCH₂C–OH

named: 3,5-dimethylhexanoic acid

4. common names: acetic acid (ethanoic acid), formic acid (methanoic acid), butyric acid (butanoic acid: smell of rancid butter), and benzoic acid (benzene with a carboxyl group or phenylmethanoic acid)

VI. Esters

A. derived from the reaction of an organic acid and an alcohol, many with pleasant flavors and fragrances

O

^{| |}

B. general formula: R – C – O – R' (where R' is from the alcohol and R is from the acid)

C. naming: named like alkanes except

1. name the side from the alcohol first, but as a radical with ending -yl

2. name the side from the acid (with the carbonyl) second, but add –oate (or just –ate) to end

O

^{| |}

3. example: CH₃CH₂C–O–CH₃ names: methyl propanoate

4. common names: n -amyl acetate (pentyl ethanoate: banana), n -octyl acetate (octyl ethanoate: oranges), ethyl butyrate (ethyl butanoate: pineapple), and n -amyl butyrate (pentyl butanoate: apricots)

Nitrogen Derivatives

I. Amine

A. based on ammonia, NH₃

B. many have an unpleasant odor, some have a fishlike smell

C. replace hydrogens of ammonia with one or more R groups

1. replace one hydrogen: primary amine

2. replace two hydrogens: secondary amine

3. replace all three hydrogens: ternary

D. general formula

1. primary: R – NH₂

2. secondary: R – NH

|

R'

3. ternary: R – N – R"

|

R'

E. naming

1. name carbon chain(s) as a radical and add amine

2. example: CH₃CH₂NH₂ = ethyl amine

3. common names: putrescine and cadaverine

II. Amide

A. carbonyl and amine group on the same carbon, always at the first carbon

O

^{| |}

B. general formula: R – C – NH₂

C. naming

1. name carbon chain and add amide

2. side chains are named from the carbonyl/amine first carbon, in alphabetical order

O

^{| |}

3. example: CH₃CH₂C–NH₂ named: propanamide

III. Nitriles

A. triple bonded nitrogen, must be on first carbon in chain

B. general formula: R – C – N

C. naming

1. name carbon chain and add nitrile

2. side chains are named from the nitrile first carbon, in alphabetical order

2. example: CH₃CH₂C = N named: propanenitrile

IV. Nitro

A. contains a nitro group

B. general formula: R – NO₂

C. naming

1. name with nitro functional group on lowest carbon number possible

2. side chains follow the numbering of carbons established by the nitro functional group, in alphabetical order

NO₂

^|

3. example: CH₃CH₂CHCH₃ named: 2 – nitrobutane

4. common names: TNT or trinitrotoluene (1-methyl-2,4,6- trinitobenzene)

V. Amino acids

A. contains a carboxyl and an amine group

O

^{| |}

B. general formula: NH₂ – R – C – OH

C. naming: amino acids have special names such as – glycine (2-aminoethanoic acid) and alanine (2-aminopropanoic acid)

Biochemistry

I. Sources of organic compound

A. Major source: petroleum (crude oil)

B. Other sources: natural gas, coal tar, fermentation

C. Fractional distillation: separates petroleum into compounds by the difference in their boiling points

D. Gasoline

1. Sources

a. Small chains being joined

b. Cracking

2. Octane rating: percent comparison between the fuel and a standard that causes "knock"

II. Types of organic reactions

A. Oxidation (burning or combustion): O₂ reacts with hydrocarbons at high temperatures to produce CO₂ and H₂O, if complete; CO may be produced in incomplete combustion

B. Substitution: one group changes places with a hydrogen or another group, problem - can't control which hydrogen is substituted and get many unwanted products

C. Addition: add something to a molecule at the carbons of a multiple bond (double or triple) by breaking one of the bonds between the carbons and freeing them up to make another bond with something else or another carbon (reverse of elmination)

D. Elimination: remove an atom from each of two adjacent carbons forming a double bond and splitting out a smaller molecule: H₂SO₄ is used as a dehydrating agent and/or catalyst: H-OH,

H-Cl, and H-NO₂ are common small molecules removed (reverse of addition)

E. Esterification: a dehydration reaction that removes a water molecule (H-OH) from between an organic acid and an alcohol joining them to form an ester and a water molecule

organic acid + alcohol –> ester + water

F. Hydrolysis and Saponification

1. Hydrolysis: add water to an ester to split it and form an organic acid and an alcohol (reverse of esterification)

ester + water –> organic acid + alcohol

2. Saponification: hydrolysis of an ester in the presence of a base produces the metallic salt of the acid or soap

G. Polymerization: formation of polymers (large numbers of carbon atoms held together by covalent bonds and linked in huge molecules of a few thousand to several million carbons); made of monomers (small units that form a repeating pattern in the polymer)

1. Addition polymerization: monmers with double or triple bonds adds to similar units forming chains or cross-linked chains; the double bond breaks freeing the carbons to bond together

a. natural rubber: repeating units of isoprene (2-methyl-1,3-butadiene) molecule is coiled so it can stretch and bounce back

b. synthetic rubber

1. chloroprene units (2-chloro-1,3-butadiene) commonly called neoprene

2. "SBR" (styrene butadiene rubber) used in tire tread

c. polyethylene (ethene units) flexible plastic used as insulation on wires

d. polyvinylchloride, PVC (chlororethene units) tough plastic used in credit cards, phonograph records, floor tiles and sprinkler pipes

e. polypropylene (acts like methylethene units) used in carpet backings and upholstery fibers

f. methyl methacrylate,