Activity 9: Cinnamaldehyde & Aldehyde Flashcards
a carbon is double bonded to an oxygen atom and single bonded to two other atoms
carbonyl group
formula of aldehyde
RCOH
formula of ketone
RCOR
- carbonyl-containing organic compound in which the carbonyl carbon atom has at least one hydrogen atom directly attached to it
- The carbonyl carbon of all other aldehydes is bonded to a hydrogen and to an alkyl (or aryl) group (R)
- Note that the carbonyl carbon of the simplest aldehyde, formaldehyde, is bonded to two hydrogens
aldehydes
- carbonyl-containing organic compound in which the carbonyl carbon atom has two other carbon atoms directly attached to it
- two carbon groups are attached to the carbonyl carbon, while in aldehydes at least one hydrogen is attached to the carbon.
Ketones
isolation of cinnamaldehyde
steam distillation
aldehyde common name
meth
eth
prop
but
pent
hex
hept
oct
non
dec
form
acet
propion
butyr
valer
capro
enanth
capryl
pelargon
capr
- The position of the carbonyl carbon does not have to be designated because it is always at the end of the parent hydrocarbon so it always has the 1-position
- Parent chain is the longest with the carbonyl group.
- In naming of the parent chain, remove the -e of the alkyl and change to -al.
- Number the parent chain in which carbon number 1 is the carbonyl group of the RCHO
- For cyclic aldehydes in which the CHO group is directly attached to a ring, the suffix -carbaldehyde is used.
- Identity and locate the substituents placed before the parent name. Follow the correct punctuation.
If in the same molecule you find:
- -OH groups, treat them as substituents with the name “hydroxy”.
- Other carbonyl (ketone) groups, treat as a substituent with the name “oxo”.
I. STEAM DISTILLATION Objectives
- Apply steam distillation in the isolation of cinnamaldehyde from cinnamon powder.
- Confirm via chemical tests the aldehyde which has been isolated.
- Compare the results in the chemical tests of the isolated cinnamaldehyde with other aldehydes and ketones.
- To determine the solubility of acetone in organic & inorganic solvents
- To analyze the chemical reactions undergone by acetone
R-OH —> RCHO —> R-COOH —> CO2 (product)
ALDEHYDES
- Aldehydes have ______ BP than alkanes while they have ______ boiling points than the corresponding alcohols because no hydrogen bonding occurs as it does with alcohols.
- As the hydrocarbon portion of aldehyde gets larger, the water solubility of aldehydes
________.
The lower members (up to 4 carbons) of aldehydes are ______ in water due to H-bonding.
The higher members do not dissolve in water because the hydrocarbon part is larger and resists the formation of hydrogen bonds with water molecules.
- higher
- lower
- decreases
- soluble
ALDEHYDES
- They have pungent, penetrating, unpleasant odors, higher-molecular-mass (_____).
The ____________ posses certain odour and flavour hence they are used as ________.
- As to state, the ___ & ___ aldehydes are gases at room temperature while the ___ through ____ straight-chain saturated aldehydes are liquids, and the higher aldehydes are solids.
- above C8
- aromatic aldehydes
- flavorants
- C1 and C2
- C3 through C11
KETONES
- Just like aldehydes, ketones have ____ BP but ____ BP compared to the corresponding ROH due to absence of hydrogen bonding.
- As to solubility, as the hydrocarbon portions get larger, the water solubility of ketones _________.
This hydrogen bonding causes low-molecular-mass aldehydes and ketones to be water _______.
- high
- lower
- decreases
- soluble
KETONES
- Ketones generally have pleasant odors, and several are used in perfumes and air
fresheners. - As to state, lower-molecular-mass ketones (___-___) are colorless liquids at room temperature.
C4-C8
Chemical Tests
- Oxidation Reaction with Tollen’s Test (Silver Mirror Test)
- Chromic Acid Test (Aliphatic or Aromatic)
- Fehling’s Test (Activity 10)
- Schiff’s Test
- Cannizzarro’s Reaction (NaOH)
- Addition of Sodium Bisulfite
- Phenylhydrazine Test (AKA: 2,4-Dinitrophenyl Hydrazine Test)
- Iodoform Test (Aldehyde vs. Ketone)
- Oxidation Reaction w/ Potassium Permanganate (Aldehyde vs. Ketone)
- Milk Test (Presence of Formaldehyde in Milk- Adulteration)
- Oxidation Reaction with Tollen’s Test (Silver Mirror Test)
Procedure: for Aldehyde
Cinnamaldehyde/ F / A / B + Tollen’s Reagent + Heat
ALDEHYDE
- BLACK PRECIPITATE or SILVER MIRROR on the glass wall’s container
KETONE (ACETONE): NO REACTION
- Chromic Acid Test (Aliphatic or Aromatic)
Cinnamaldehyde/ F / A / B + Potassium dichromate + Heat
Expected Observable Result: BLUE-to-GREEN COLOR PRECIPITATE (Cr+3)
- Fehling’s Test
Fehling’s Reagent:
*________: blue aqueous solution of copper(II) sulfate pentahydrate crystals
*________: clear solution of aqueous potassium sodium tartrate (also known as Rochelle salt) and a strong alkali (commonly sodium hydroxide)
Acetone + Fehling’s Solution + Heat
- Fehling’s A
- Fehling’s B
Expected Observable Result:
A. Upon heating the aldehyde is oxidized, its corresponding carboxylic acid, while cupric oxide
(CuO) is reduced to cuprous oxide (Cu2O-RED PRECIPITATE) while a negative result with a ketone.
B. Aromatic aldehydes do not respond to Fehling’s test (DEEP TRANPARENT BLUE SOLUTION) .
- Schiff’s Test
Acetone + Shiff’s Reagent + Heat
Schiff’s Reagent:
* Chemical Formula: C19H21N3S2O7.4H2O
- Composition:
- Water (H2O) >98%
- Hydrochloric Acid (HCl) <1%
- Sodium Metabisulfite <1%
- Basic Fuchsin Hydrochloride <1%
Expected Observable Result:
ALDEHYDE:
BISULFITE ADDUCT: PURPLE or
MAGENTACOLORED SOLUTION
KETONE (ACETONE): NO REACTION
- Cannizzarro’s Reaction (NaOH)
Acetone + 6N NaOH + Heat
- Addition of Sodium Bisulfite
Acetone + Saturated Sodium Bisulfite
Expected Observable Result: CRYSTALLINE PRECIPITATE (presence of Carbonyl Group)
- Phenylhydrazine Test (AKA: 2,4-Dinitrophenyl Hydrazine Test)
- _________ is used which reacts with carbonyl groups, forming phenylhydrazones.
- _________ are colored compounds, and their color differs according the whether the sample contains an aldehyde or ketone.
*The condensation reaction results in the formation of a ____________, which precipitates out of solution.
- 2,4-dinitrophenylhydrazine
- Phenylhydrazones
- hydrazone
Expected Observable Result:
The formation of a yellow,
orange or orange-red
precipitate.
- Iodoform Test (Aldehyde vs. Ketone)
- ________ is used to check the presence of carbonyl compounds with the structure R-CO-CH3.
- It can be used to identify aldehydes or ketones.
If an aldehyde gives a positive iodoform test, then it must be __________ since it is the only aldehyde with a CH3C=O group or ketone in which a methyl group is one of the groups immediately connected to the carbonyl carbon.
Such a ketone is referred to as ___________ such as acetone
- Iodoform test
- acetaldehyde
- methyl ketone
- Oxidation Reaction w/ Potassium Permanganate (Aldehyde vs. Ketone)
Cinnamaldehyde/ F / A / B + Acidified KMnO4
R-CHO + KMnO4 → R-COOH
H+
- reaction is relatively slow and requires a high temperature to proceed at a reasonable rate
- Milk Test (Presence of Formaldehyde in Milk- Adulteration)
Cinnamaldehyde/ F / A / B + Milk + H2O + 10% FeCl3 + H2SO4 + Heat
Expected Observable Result:
Formaldehyde (Methanal): Violet Color Solution
Important Aldehydes and Ketones
- Formalin
- Aromatic Aldehydes as Flavorants
- Acetone
- Acetophenone
- Carvone
- Cinnamaldehyde
- aqueous solution containing 37% formaldehyde by mass or 40% by volume
- most widely used preservative chemical in embalming fluids used by morticians
Mechanism of action:
- involves reaction with protein molecules in a manner that links the protein molecules together;
- the result is a “hardening” of the
protein
formalin
- vanilla flavoring (_______)
- almond flavoring (_______)
- cinnamon flavoring (_______)
- vanillin
- benzaldehyde
- cinnamaldehyde
ALDEHYDE
- Antiseptic: 80% solution
- Cleansing solution with ROH
- Menstruum/Solvent for Plant Extraction: preparation of _________ in place of ether
- Industrial Solvent for dissolving fatty bodies, resins, pyroxylin, mercurials, manufacture of chloroform, chlorobutanol, and ascorbic acid, can also be used to remove water from glassware in the laboratory & major component of some nail polish removers
- oleoresins
ACETONE
- characteristic sweet odor (such as cherry, jasmine, honeysuckle, almond, strawberry, etc.), so they are included in perfume industries
acetophenone
- chief odoriferous constituent Spearmint (Mentha spicata or Mentha cardiaca)
- Uses: Primarily as a flavoring agent
- used as a carminative in doses of 0.1 mL
carvone
- The flavoring in oil of cinnamon; obtained by steam distillation from the bark of the cinnamon tree
- has a carminative action
Cinnamaldehyde
