PHA615 LAB: Classification Test for HC, Organic Halides, and Amines

Solublity in H2SO4

tests for alkenes

positive: reacts with alkenes thru Ae rxn

negative: all HC

Ignition Test

more soot = aromatic

less soot = aliphatic

Baeyer’s Test

does not colorized/brown ppt = active saturation

no rxn = alkanes, aromatic

Baeyer’s Test

uses 2% KMnO4

Bromine Test

orange-brown = alkene/alkyne (due to Ae)

no rxn = alkane/aromatic

Bromine Test

Br2 in CCl4

Iodine Test

I2 solution

Iodine Test

tan-colored solid; to confirm presence of alkene/alkyne

Nitration Test

yellow oily layer = aromatic

Nitration Test

H2SO4 and HNO3

Basic oxidation

decolorized = alkenes and alkyl side chain

Basic oxidation

2% KMnO4

10% NaOH

Beilstein/Copper Halide Test

green flame test = presence of halide

Rxn with Ethanolic AgNO3

classifies type of RX

faster in tertiary RX

Rxn with NaI in Acetone

classifies type of RX

faster in primary RX

Rxn with Ethanolic AgNO3

2% alcoholic AgNO3

Rxn with NaI in Acetone

15% NaI in anhydrous acetone

Hinsberg Test

tests for type of amine
1 - soluble

2- insoluble

3- no rxn

Hinsberg Test

10% NaOH and benzene sulfonyl Cl

Solubility w/ HCl and NaOH

HCl + Amine = Soluble

Solubility w/ HCl and NaOH

NaOH + Amine = insoluble

Hydrocarbons

is a one of the two general classifications of organic compounds. These compounds are composed entirely of C and H atoms that are arranged and bonded in specific ways.

Hydroxy

ROH and ArOH

Mercapto

thiol and sulfides

Amino

for amines

Amido

amindes

Halo

organic halides

Carbonyl

aldehydes and ketones

Carboxyl

carboxylic acid and derivatives

Branching

decreases HC length making the HC more compact and dense.

The # of carbon atoms

increases hydrophobicity = less polar.

H-bonding

-C=O, -COOH, -OH, -NH2

Dipole-Dipole

OH, -NH2, -X, -SH, -C=O, -COOH

London Dispersion / Hydrophobic

HC

Aromaticity

is based on distinct characteristics present in a hydrocarbon as well as its conformance to the Huckel’s rule.

Aromatic

is a hydrocarbon that contains one or more benzenelike rings and can be described as: • Cyclic • Planar • Possess conjugated double bonds (ex. C=C—C=C) • Possess 4n+2 π electrons (Huckel’s rule).

HC

are generally soluble in organic solvent / insoluble in water.

Solubility

is inversely related to melting point (↑ MP = ↓ solubility)

Combustibility

is a measure of how easily a substance bursts into flame through fire or combustion

Flammability

is the ease with which a combustible substance can be ignited causing fire, combustion, or even explosion.

Test of Unsaturation

It can be used to determine the presence of a double/triple bond (unsaturation) in a compound.

Test of Unsaturation

It can differentiate active unsaturation from aromatic compounds.

Test of Unsaturation

Baeyer’s test, Bromine test, and Iodine test

Baeyer’s test

uses KMnO4 and is a form of oxidation reaction which forms a brown suspension/sludge. It detects the presence of active unsaturation like in alkenes and alkynes

Bromine test

uses Br2 in CCl4 to confirm the presence of double/triple bonds. It is an addition reaction in which the Br2 solution is decolorized when mixed with unsaturated compounds.

Iodine test

uses I2 solution and is also an addition reaction used to confirm the presence of alkene/alkynes. The positive result for this test is the formation of a tan-colored solid while retaining the color of the I2 solution.

Nitration Test

is a common substitution reaction for aromatic molecules. It is used to detect the presence of benzene rings in a compound.

Nitration Test

The formation of a yellow oily layer confirms the presence of a benzene ring.

Basic Oxidation

This test uses KMnO4 in NaOH solution and is often referred to as mild oxidation.

Basic Oxidation

It can be used to detect the presence of alkene and benzylic carbon (must have benzylic hydrogen) that are both susceptible to oxidation.

Basic Oxidation

A brown precipitation or suspension confirm the presence of the target organic compounds.

Organic halides

or haloalkanes (RX) are organic compounds that contains a halogen moiety (-X = F, Cl, Br, and I).

RX

is soluble in organic solvent but are insoluble in water despite being polar.

RX

can exhibit dipole-dipole interactions because of the C-X bond where the polarity is shifted -X causing it to be polar.

RX

reacts via substitution and elimination reactions.

decreases

The bond strength of C-X _ as the size of the halogen increases. Iodine is a better leaving group during reactions compared to fluorine.

Beilstein Test

This is a flame test that detects the presence of halogens from samples.

Beilstein Test

It uses CuO that reacts with the halogen forming copper-halide compounds which is visible via the formation of blue-green flame.

SN1

• unimolecular; reaction is dependent only on the RX

  • Tertiary RX with “stable” carbocation formed from their alpha carbons uses this mechanism.

SN2

bimolecular; reaction is dependent on the RX and the Nü. • This mechanism is common for primary and secondary RX.

SN1

Reaction with Alcoholic AgNO3. • The Ag in AgNO3 acts as a Lewis acid and promotes the formation of the carbocation. AgX is formed as a by-product together with the R+ .

SN2

Reaction with NaI in Acetone • The I- in NaI in acetone displaces the X in not sterically hindered RX (primary or secondary RX) resulting in R-I (alkyl iodide) and a NaX (Br or Cl) salt. • NaI is soluble in acetone but NaBr/NaCl are not and will form a precipitate indicating the occurrence of an SN2 reaction.

Amines

are nitrogen-containing organic compounds which can be classified as primary, secondary, or tertiary based on the number of alkyl (R-) groups attached to the nitrogen atom.

RNH2

are basic and have a characteristic fishy odor and can exist as liquids (low carbon) or solids (higher carbon) depending on the number of carbons.

hydrogen bonding

The presence of H atoms results into _ which cause higher boiling for primary amines (BP primary > secondary > tertiary).

Amines

_ are soluble in water due to its ability to undergo H-bonding. However, as the size of the alkyl group increases, water solubility decreases.

Aromatic

_ amines (ex. Aniline) readily undergoes atmospheric oxidation can gets colored as a result

Hinsberg Test

This uses benzene sulfonyl chloride to differentiate between primary, secondary, and tertiary amines

soluble

Primary amines forms alkali _ sulfonamide product.

insoluble

Secondary amines forms alkali _ sulfonamide product.

do not

Tertiary amines _ react.

blue-green

A _colored flame indicates the presence of Br, Cl, & I

Solubility with HCl and NaOH

Hinsberg Test

Reaction with NaI in Acetone

Reaction with Ethanolic AgNO3

Beilstein Test or Copper Halide Test

Basic Oxidation Test

Nitration Test

Baeyer’s test

Ignition Test

Solubility in H2SO4

Ignition Test

It can be used to classify aliphatic from aromatic hydrocarbons.

Aliphatic

HC burns with yellow flame that are less sooty

Aromatic

HC burns with yellow flame that are more soot

active unsaturation

A (+) decolorized result and (+) brown suspension/sludge in Baeyer’s test, confirms the presence of _ in cyclohexene.

Baeyer’s Test

KMnO4 with alkenes produces a vicinal diol or glycol. This is mild oxidation reaction.

Baeyer’s Test

KMnO4 does not affect alkanes (unreactive) and aromatic compounds (too stable, inactive unsaturation).

Bromine Test

will start as orange-brownish solution and will decolorize if the test is positive for the presence of alkenes or alkynes. • Br2 can undergo AE reaction mechanism to add itself to the double or triple bond. • Br2 can mix with aromatic compound in the presence of the appropriate catalysts, but will not react with alkanes upon mixing.

Nitration Test

The reaction occurs via SE mechanism which is specific for aromatic compounds. The nitrating mixture composed of H2SO4 and HNO3 creates the electrophile -NO2+ .

Basic Oxidation

Alkenes are able to undergo mild oxidation with KMnO4 resulting to a decolorized solution (similar to Baeyer’s test).

Alkyl side-chain on a benzene ring (benzylic position) is fairly resistant to oxidation but in an alkaline solution with KMnO4, the benyzlic hydrogen is easily oxidized into a -COOH moiety.

Chlorobenzene

_ did not react to either SN1 or SN2 because it is an aromatic halides.

SN1

Alkyl halide (RX) - faster reaction is observed with more stable carbocation. • Solvent - any polar solvent that increases the stability of the carbocation will also speed up the reaction rate. • Leaving group - best leaving groups are those that can stabilize the anion (eg., weakest bases).

SN2

Steric congestion - the more steric present, the slower the reaction. • Solvent - exposing the Nü to a more polar solvate = more reactive iodide. • Nucleophile - atoms from same family in periodic table, the larger members of the family are better Nü. • Leaving group - best leaving groups are those that can stabilize the anion (eg., weakest bases).

Hinsberg test

will differentiate primary, secondary, and tertiary amines based on the products they form.

HCl

In _ solutions, amine are soluble due to the ability to form H-bonding with the -Cl moiety. Amines + _ is a form of a neutralization reaction.

NaOH

In _ solutions, amines are insoluble due to lack of intermolecular attraction (amine only have weak H-bonding and dipole-dipole) to break the ionic bond within NaOH and the presence of hydrophobic moieties.