O Chem 2 Lab Final Flashcards
What does sodium hypochlorite do to the secondary alcohol in the oxidation of an unknown alcohol lab?
It turns the alcohol into a ketone
What is sodium hypochlorite in the oxidation of an unknown alcohol?
Oxidizing Agent
How was excess hypochlorite tested for in the oxidation of an unknown alcohol lab?
KI-starch paper
What indicated an excess of hypochlorite in the oxidation of an unknown alcohol lab?
The starch paper turned blue
(If the paper remained white, add NaOCl until paper turned blue)
What was used as a reducing agent in the oxidation of an unknown alcohol lab?
Sodium bisulfite
What was the role of sodium bisulfite in the oxidation of an unknown alcohol lab?
Used to quench excess hypochlorite remaining after the reaction has gone to completion
(Checking KI-starch paper to make sure it remained white)
What does quenching mean?
Forcing any residual oxidizer to react, stopping the reaction
What was used to achieve a basic solution in the oxidation of an unknown alcohol lab?
6M sodium hydroxide
What did the base do in the oxidation of an unknown alcohol lab?
Neutralized the residual acetic acid (forming acetate) allowing it to be water soluble while the product remained un-ionized
What type of extraction was used in the oxidation of an unknown alcohol lab?
Liquid/liquid
What was used to extract the product into the organic layer (bottom layer) in the oxidation of an unknown alcohol lab?
Methylene chloride
What method is used for liquid/liquid extraction?
Separatory funnel
What is used for the drying agent and how is it removed?
Magnesium sulfate (MgSO4) removed by gravity filtration
How is solvent often removed at the end of the experiment?
Using a rotary evaporator or hot plate/ snorkel
What conversion should occur in the IR stretches in the oxidation of an unknown alcohol lab?
O-H stretch to C-O double bond stretch
What is the solvent in the oxidation of an unknown alcohol lab?
Acetic Acid (CH3CO2H)
What happened in the conversion of carvone to carvacrol lab?
The carvone reaction converted a chiral compound to an achiral compound through an acid-catalyzed elimination
What is the catalyst/solvent in the conversion of carvone to carvacrol lab?
6M H2SO4
What is this reagent?
(R)-(-) Carvone
What is this product?
Carvacrol
What was used to run the reaction in the conversion of carvone to carvacrol lab?
Reflux
What is significant about reflux?
It is a boiling point reaction without losing solvent
What type of extraction was used in the conversion of carvone to carvacrol lab?
liquid/liquid
What was the product extracted into in the conversion of carvone to carvacrol lab?
Diethyl ether
What was the ether extract used for in the conversion of carvone to carvacrol lab and why was it used?
Sodium Bicarbonate used to neutralize the acid
What was used to dry the product in the conversion of carvone to carvacrol lab?
Sodium sulfate (Na2SO4)
What peaks were changed in the IR of the conversion of carvone to carvacrol lab?
C-O double bond carbonyl changed for O-H stretch and arena peak/undertones
What is used to form an ether in Williamson-Ether synthesis?
An alcohol and alkyl halide under basic conditions
Why are primary alkyl halides typically used for Williamson Ether Synthesis?
The alkyl halide serves as the electrophile for an Sn2 reaction
What type of alkyl halide was used in the Williamson-Ether Synthesis lab?
Unknown primary Alkyl Bromide
What were the catalysts used in the Williamson-Ether Synthesis lab?
KOH (base catalyst) & TBAB (phase-transfer catalyst)
What does TBAB stand for in the Williamson-Ether Synthesis lab?
Tetra-N-butylammonium bromide
What does TBAB do in the Williamson-Ether Synthesis lab?
Phase transfer catalyst that works by helping ions cross between the organic and aqueous phase
What was used to run the reaction in the Williamson-Ether Synthesis lab and why?
Microwave reflux to speed up the reaction by holding the reaction at a constant temperature and pressure
What isolation method was used in the Williamson-Ether Synthesis lab?
Liquid/liquid extraction
What was used to extract the mixture in the Williamson-Ether Synthesis lab?
diethyl ether
What layer was the product in the Williamson-Ether Synthesis lab?
organic layer / washed with potassium hydroxide to remove impurities
What was used as the drying agent in the Williamson-Ether Synthesis lab?
sodium sulfate
What was used to purify the product in the Williamson-Ether Synthesis lab?
column chromatography to separate components of a mixture on a milligram-to-milligram scale
What is the mobile phase of the column chromatography in the Williamson-Ether Synthesis lab?
Methylene Chloride (DCM) (less polar)
What is the stationary phase of column chromatography in the Williamson-Ether Synthesis lab?
Silica gel (more polar)