Oc2englteil2

8/6/2019 Oc2englteil2

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III. Classification of organic compound

1. Hydrocarbons

CH3-CH3; CH2=CH2; CHCH;

CH2=CH-CH=CH2

CH2conjugated isoladouble bonds doub

2. Compounds with single-bonded functional groups

R-OH alcohols; R-O-R ethers; R-NH2 amines; R-CH2-X alky

(X= -F; -Cl;

3. Carbonyl compounds

R CO

R'

R' = -H aldehydes;

-R (alkyl, aryl) ketones;

-OH carboxylic acids

4. HeterocyclesN

;


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Hydrocarbons

Hydrocarbons aromat

aliphatic hydrocarbons

alkanes alkenes alkinesC Hn 2n+2 C Hn 2n C Hn 2n-2ethane ethene ethinee.g.

e.g

CH

CH

CH3

CH3

CH2

CH2

CH CH


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Aliphatic hydrocarbons

Alkanes CnH2n+2 Alkenes CnH2n

Number ofC-atoms

Summationformula

Name Summationformula

Name

1 CH4 Methane

2 C2H6 Ethane C2H4 Ethene

3 C3H8 Propane C3H6 Propene

4 C4H10 Butane C4H8 Butene

5 C5H12 Pentane C5H10 Pentene

6 C6H14 Hexane C6H12 Hexene

7 C7H16 Heptane C7H14 Heptene

8 C8H18 Octane C8H16 Octene

9 C9H20 Nonane C9H18 Nonene

10 C10H22 Dekane C10H20 Dekene


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III. Classification of organic compounds1. Hydrocarbons 4

AlkanesCnH2n+2

Properties

poor reactivity

formation of structural isomers

C1 - C4 gases; C5 - C16 liquids; from C17 solids

non-polar compounds, hydrophobic

Natural sources

methane: natural gas, biogas,in rumen (from cellulose)

ethane, propane, butane: natural gas

higher alkanes, petroleum,cycloalkanes: plants(terpenes)


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Isomerism of alkanes

Isomers are compounds with equal summation formula,

but different molecular structure.

Structural isomers are compounds with a differentconstitution (constitutional isomers)They differ in the order in which their atoms areconnected to each other.They have different chemical and physical properties.

Chain isomers are compounds with different chainstructure (chain branching).

Summationformula

Name Number ofisomers

CH4 Methane 1

C2H6 Ethane 1

C3H8 Propane 1

C4H10 Butane 2

C5H12 Pentane 3

C6H14 Hexane 5

C7H16 Heptane 9C8H18 Octane 18

C9H20 Nonane 35

C10H22 Dekane 75

C20H42 Eicosane 366319


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Structural isomerism

greek: isos equalmeros part

n- compound i -compound

C4H10 C C C C

n-butaneC C C1 2 3

C

2-methylpropane

isobutane

C5H12 C C C C C

n-pentane

C C C1 2 3 C4

C

2-methylbutane

isopentane

C C C1 2 3

C

C

2,2-dimethyl-propane

C6H14 C C C C C C

n-hexane

C C C1 2 3

C4

C

C5 2-methylpentane

isohexane

C C C1 2 3

C4

C

C5

3-methylpentane

C

C C C1 2 3

C4

C2,3-dimethylbutane

C

C C C1 2 3

C4

C

2,2-dimethylbutane


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Names of different carbon atoms

C C C C

C C

C

C1

2345

6

78

primary C-atoms: 1, 5, 6, 7, 8

secondary C-atom: 3

tertiary C-atom: 4

quaternary C-atom: 2


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Application of alkanes

for heating purpose(ox. with O2)

methane, ethane, propane,butane, fuel oil, petroleumhydrocarbons

fuels (ox. with O2) gasoline (octan number),diesel fuel, kerosene

solvents,extracting agents (e.g. forvegetable oils)

pentane, hexane, heptane,cyclohexane

surfactants C12-C18 n-alkanes

preparation of ethylene,propylene

dehydrogenation of ethane,propane


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Reactions of alkanes

Halogenation of alkanes:

C6H

14Br

2+

C

6H

13Br + BrH

Oxidation of paraffines:

CH3

C C C C CH3

H

H

H

H

H

H

H

H

O2 / cat.

CH

3C C C C

H

H

H

H

H

H

H

H

COOH

Sulfochlorination:

CH3

C C C C CH3

H

H

H

H

H

H

H

H

SO2Cl

2

- HCl

CH3

C C C C SO2Cl

H

H

H

H

H

H

H

H


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Cycloalkanes

cyclopropane cyclobutane(bp. -34,5C) (bp. 11C)

bond angle: 60

strong ring strain

cyclopentane cyclohexane(bp. 49,5C) (bp. 80,8C)

bond angle: 109free of tension

Stress theory by BAYER

chair-form boat-form(more stable)


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Alkenes - olefins

CnH2n

Natural sources

like alkanes: petroleum, natural gas, plants (terpenes)

Application

products starting materials

synthetics (polymers)(PE, PP, PVC)

H2C=CH2; H2C=CH-CH3;H2C=CHCl

synthetic rubber H2C=CH-CH=CH2

isooctane (OZ=100) isobutene

alcohols (2-Propanol) propene


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Typical reactions of olefines

addition:

BrBr Br +

polymerisation:

CH2 CH2 CH2 CH2n

cycloaddition:

+

ethene 1,3-butadiene cyclohex


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Unsaturated cyclic compounds

cyclohexene 1,3-cyclohexadiene

1

2

3

4

5

6


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Aromatic hydrocarbons

benzene

aromaticity

cyclic conjugation is a necessary but non sufficientrequirement

Hckels rule: number of-electrons must be equal to 4n + 2,

where n is an integer

benzene: 6 -electrons (n = 1)

mesomerism of benzene

H

H

H

H

H

H


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Positional isomers of dichloro benzene

Cl

Cl

Cl

Cl

1,2-dichloro benzene

o- dichloro benzene

1,3- dichloro benzene

m- dichloro benzene

1,4-

p- d

o = ortho position m = meta position p


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Technical important aromatic compounds

CH3

O

2

BENZENEin the past: solvent

TOLUENEsolvent, production of insecticides

and TNT, additive for fuels

T

BIPHENYL

preserving agent (E 230),production of PCB(polychlorinated biphenyl)

NAPHT

production of pharmaceutical p


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Toxicity of aromatic compounds(cause long-term demage)

CH3

Cln

NH2

R

BENZENE

blood, nervoussystem

carcinogenic

TOLUENE

blood,nervous system

CHLOROBENZEN

E

liver, kidney

DERIVATIVES OF

ANILIN

blood,nervous system

NHNH2

R

OH

R

NO2

R

DERIVATIVES OF

PHENYLHYDRAZIN

carcinogenic

DERIVATIVES OF DERIVATIVES OFPHENOLE NITROBENZENE

liver, kidney, blood bloodcarcinogenic?

ClCl

BIPHENYL, PCB

liver, kidney, blood, nervous system

carcinogenic

BENZ[a]-PYRENE

strong carcinogenic


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Alkines

CnH2n-2

most important: acetylene (ethine) HCCH

Preparationpyrolysis of hydrocarbons

Properties of acetylene

colourless gas

mixtures with air are explosive (content of acetylene3 -70 %)

Application of acetylene: preparation of 1,4-butanediol, trichloroethylene, acrylic acid

vinylation of higher acids and alcohols

welding of steel


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III. Classification of organic compounds

Addition to the triple bond

C C

2 H 2, NiC C

C CCH

H

Na, fl.NH 3 trans

H2, PdC CC

HHcis

Cl2

C C

ClCl

C CCl2

Cl Cl

ClCl

HClC C

Cl

C C

Cl

Cl

HCl

H

H

H

H2O

HgSO 4, H 2SO 4C C C C

H

H

OH H O

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