Module 6: SIMPLE DISTILLATION AND CHROMATOGRAPHY Flashcards
- involves the process of “separating two or more liquids” homogenously mixed but with different boiling points (at least 20 degrees difference)
SIMPLE DISTILLATION
- when the mixture of liquids to be distilled is heated, the “liquid with the _________ boiling point” turns into vapors first
lowest
- as the distillation progresses, the concentration of the lowest boiling component will ___________
steadily decrease
- when the temperature again stabilizes, another pure fraction of the distillate can be collected
fractional distillation
- further acidification of the previous reaction of acetone with sodium nitroprusside and sodium hydroxide using acetic acid will convert the wine-red color into _______________, thereby confirming the distillate as acetone (as elaborated by Le Nobel)
magenta-red solution
- as the solution starts to boil, the liquid with the ______ boiling point turns to vapors first
lowest
- this vapor would then be “condensed back into
liquid” inside the condenser, which will then be
collected as the ________
distillate
lowering the pressure, thus, lowering the boiling point of the
substance
note!
separation of the liquid mixture can be detected through _______
ignition test
- an organic sample (acetone) will ignite, thereby can identifying what type of compound is the ____________
distillate
acetone (a ketone) will react with sodium nitroprusside and sodium hydroxide producing a ________________ due to the formation of acetone nitroprusside ion complex
wine-red solution
react with acetone (a ketone) producing a wine-red solution
CH3COCH3 + Na2[Fe(CN)5NO] [Fe(CN)5NO(CH2COCH3)] NaOH2+
SODIUM NITROPRUSSIDE TEST
reaction of acetone with sodium nitroprusside and sodium hydroxide using _____________ will convert the wine-red color into magenta-red solution
GLACIAL ACETIC ACID
- the process of separating the substances in a complex mixture by their “different affinities” to an “adsorbent”
CHROMATOGRAPHY
- derived from the Greek words, chroma meaning _____, and graphein meaning to _______
chroma = color
graphein = write
(literally means color writing)
Chromatography commonly used for analyzing mixtures of
______________
colored chemicals
- this technique involves separation of constituent elements of the mixture
Chromatography
Chromatography invented by a Russian botanist, _________________, in 1901, while researching on plant pigments
Mikhail Semyonovich Tsvet
- a liquid or solid that is fixed in a place during the process
STATIONARY PHASE
- usually a high quality filter paper, or an adsorbent
STATIONARY PHASE
- either liquid or gas which moves the samples through the stationary phase during the process
MOBILE PHASE
- solvent or a mixture of solvents
MOBILE PHASE
components of the sample will separate readily according to how strongly they “__________ on the stationary phase” versus how readily they “________ in the mobile phase”
- adsorb
- dissolve
- organic compounds interact with adsorbents at different
___________________
rates and interaction
- it can only have weak Van der Waals forces of attraction for the adsorbent
non-polar
interacts through “dipole-dipole interactions or hydrogen bonding”
polar
_________________ absorb strongly on stationary phase (adsorbent)
polar compounds
__________ will be only weakly absorbed, and thus, has higher affinity with the mobile phase (solvent)
non-polar compounds
the extent of separation is measure by the _______________
retention factor or the Rf value
Rf value depends on the
_____________ and
_______________ of the components of the sample
- relative solubility
- adsorptive properties
𝑅𝑓 𝑣𝑎𝑙𝑢𝑒 formula
𝑅𝑓 𝑣𝑎𝑙𝑢𝑒 =
𝑑𝑖𝑠𝑡𝑎𝑛𝑐𝑒 𝑡𝑟𝑎𝑣𝑒𝑙𝑙𝑒𝑑 𝑏𝑦 𝑡ℎ𝑒 𝑠𝑜𝑙𝑣𝑒𝑛t
_____________ draws a developing solvent up the TLC plate
capillary action
involves a stationary phase made up of an adsorbent (silica gel) coated over an “inert solid plate” (usually aluminum), and a mobile phase made up of a “solvent system” (mixture of appropriate solvents)
THIN LAYER CHROMATOGRAPHY
the adsorbent will also ______________ part or all the mixture (as more solvent comes by, the mixture will again go into solution, move further and be reabsorbed)
reabsorb
- as this solvent pass through the spot, the “mixture will be ________” and will begin to “move with the solvent front”
dissolved
- largely depends on adhesion and cohesion forces which allows the mobile phase to move along the stationary phase due to surface tension
PAPER CHROMATOGRAPHY
passage of the solvent front through the adsorbent is known as _____________
developing the plate
Paper Chromatography largely depends on __________ and __________
adhesion and cohesion forces
SIMPLE DISTILLATION
= DISTILLATE B
temperature:?
compound:?
polarity:?
ignition test:?
rxn with Na nitroprusside:?
rxn with acetic acid:?
temperature: collected at ~100°C
compound: water
polarity: polar
ignition test: no ignition
rxn with Na nitroprusside: light pink color
rxn with acetic acid: yellow color
- the paper is placed inside a ____________
closed chamber/container
- it is important that the solvent level is __________ with samples
below the spots
container should be covered during the process
prevent volatilization
PAPER CHROMATOGRAPHY
AMINO ACID: glycine
THEORETICAL Rf VALUE:?
0.57
spraying the paper with a solution that reacts with the sample allows ___________
visualization of the spots
the paper is _______________ and then just stands in the bottom of the container
coiled or formed into cylinder
_________ solution reacts with amino acids giving colored compounds usually brown or purple known as _____________
- ninhydrin
- Ruhemann’s purple
SIMPLE DISTILLATION
= DISTILLATE A
temperature:?
compound:?
polarity:?
ignition test:?
rxn with Na nitroprusside:?
rxn with acetic acid:?
temperature: collected at ~57°C
compound: acetone
polarity: non-polar
ignition test: burn with luminous flame
rxn with Na nitroprusside: wine red color
rxn with acetic acid: magenta red color
PAPER CHROMATOGRAPHY
AMINO ACID: lysine
THEORETICAL Rf VALUE:?
0.53
PAPER CHROMATOGRAPHY
AMINO ACID: phenylalanine
THEORETICAL Rf VALUE:?
0.91
