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O Chem Reaction Mechanisms > O Chem 2 Lab Final > Flashcards

O Chem 2 Lab Final Flashcards

(104 cards)

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1
Q

What does sodium hypochlorite do to the secondary alcohol in the oxidation of an unknown alcohol lab?

A

It turns the alcohol into a ketone

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1
Q

What is sodium hypochlorite in the oxidation of an unknown alcohol?

A

Oxidizing Agent

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2
Q

How was excess hypochlorite tested for in the oxidation of an unknown alcohol lab?

A

KI-starch paper

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3
Q

What indicated an excess of hypochlorite in the oxidation of an unknown alcohol lab?

A

The starch paper turned blue

(If the paper remained white, add NaOCl until paper turned blue)

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4
Q

What was used as a reducing agent in the oxidation of an unknown alcohol lab?

A

Sodium bisulfite

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5
Q

What was the role of sodium bisulfite in the oxidation of an unknown alcohol lab?

A

Used to quench excess hypochlorite remaining after the reaction has gone to completion

(Checking KI-starch paper to make sure it remained white)

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6
Q

What does quenching mean?

A

Forcing any residual oxidizer to react, stopping the reaction

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7
Q

What was used to achieve a basic solution in the oxidation of an unknown alcohol lab?

A

6M sodium hydroxide

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8
Q

What did the base do in the oxidation of an unknown alcohol lab?

A

Neutralized the residual acetic acid (forming acetate) allowing it to be water soluble while the product remained un-ionized

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9
Q

What type of extraction was used in the oxidation of an unknown alcohol lab?

A

Liquid/liquid

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10
Q

What was used to extract the product into the organic layer (bottom layer) in the oxidation of an unknown alcohol lab?

A

Methylene chloride

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11
Q

What method is used for liquid/liquid extraction?

A

Separatory funnel

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12
Q

What is used for the drying agent and how is it removed?

A

Magnesium sulfate (MgSO4) removed by gravity filtration

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13
Q

How is solvent often removed at the end of the experiment?

A

Using a rotary evaporator or hot plate/ snorkel

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14
Q

What conversion should occur in the IR stretches in the oxidation of an unknown alcohol lab?

A

O-H stretch to C-O double bond stretch

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15
Q

What is the solvent in the oxidation of an unknown alcohol lab?

A

Acetic Acid (CH3CO2H)

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16
Q

What happened in the conversion of carvone to carvacrol lab?

A

The carvone reaction converted a chiral compound to an achiral compound through an acid-catalyzed elimination

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17
Q

What is the catalyst/solvent in the conversion of carvone to carvacrol lab?

A

6M H2SO4

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18
Q

What is this reagent?

A

(R)-(-) Carvone

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19
Q

What is this product?

A

Carvacrol

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20
Q

What was used to run the reaction in the conversion of carvone to carvacrol lab?

A

Reflux

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21
Q

What is significant about reflux?

A

It is a boiling point reaction without losing solvent

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22
Q

What type of extraction was used in the conversion of carvone to carvacrol lab?

A

liquid/liquid

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23
Q

What was the product extracted into in the conversion of carvone to carvacrol lab?

A

Diethyl ether

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24
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
25
What was used to dry the product in the conversion of carvone to carvacrol lab?
Sodium sulfate (Na2SO4)
26
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
27
What is used to form an ether in Williamson-Ether synthesis?
An alcohol and alkyl halide under basic conditions
28
Why are primary alkyl halides typically used for Williamson Ether Synthesis?
The alkyl halide serves as the electrophile for an Sn2 reaction
29
What type of alkyl halide was used in the Williamson-Ether Synthesis lab?
Unknown primary Alkyl Bromide
30
What were the catalysts used in the Williamson-Ether Synthesis lab?
KOH (base catalyst) & TBAB (phase-transfer catalyst)
31
What does TBAB stand for in the Williamson-Ether Synthesis lab?
Tetra-N-butylammonium bromide
32
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
33
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
34
What isolation method was used in the Williamson-Ether Synthesis lab?
Liquid/liquid extraction
35
What was used to extract the mixture in the Williamson-Ether Synthesis lab?
diethyl ether
36
What layer was the product in the Williamson-Ether Synthesis lab?
organic layer / washed with potassium hydroxide to remove impurities
37
What was used as the drying agent in the Williamson-Ether Synthesis lab?
sodium sulfate
38
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
39
What is the mobile phase of the column chromatography in the Williamson-Ether Synthesis lab?
Methylene Chloride (DCM) (less polar)
40
What is the stationary phase of column chromatography in the Williamson-Ether Synthesis lab?
Silica gel (more polar)
41
What phase did the product remain in the Williamson-Ether Synthesis lab and why?
mobile phase because it is less polar than the highly polar stationary phase
42
What stretch transition was seen in the Williamson-Ether Synthesis lab?
O-H stretch to C-O-C stretch
43
What was used for characterization in the Williamson-Ether Synthesis lab?
Thin Layer Chromatography (TLC) used to check product formation and product purity
44
What were the 3 spots on the TLC plate in the Williamson-Ether Synthesis lab?
4-bromophenol, unknown alkyl halide, and purified product
45
What was the stationary phase of TLC in the Williamson-Ether Synthesis lab?
silica gel (polar) --> polar compounds bind to the silica gel and do not migrate to top of plate
46
What was the mobile phase of TLC in the Williamson-Ether Synthesis lab?
methylene chloride (less polar) --> less polar compounds remain in the mobile phase and migrate to the top of the plate with the solvent front
47
How do you calculate Retention factor?
Rf = distance from origin to spot / distance from origin to solvent front
48
What side does the nucleophile attack on an epoxide in acidic conditions?
Most substituted
49
What side does the nucleophile attack on an epoxide in basic conditions?
Least substituted
50
Why was ammonium chloride used in the basic workup in the acid v base nucleophilic ring-opening of 1,2 epoxygexane lab?
To avoid ether cleavage (ethers cleave in strongly acidic conditions)
51
What are the acidic reagents in the acid v base nucleophilic ring-opening of 1,2 epoxyexane lab?
H2SO4 & methanol
52
What are the basic reagents in the acid v base nucleophilic ring-opening of 1,2 epoxyhexane lab?
1. NaOCH3, methanol 2. NH4Cl
53
What was used to run the reaction in the acid v base nucleophilic ring-opening of 1,2 epoxyhexane lab?
Reflux
54
What isolation method was used in the acid v base nucleophilic ring-opening of 1,2 epoxyhexane lab?
liquid/liquid extraction
55
What was used to wash the reaction mixture in the acidic conditions in the acid v base nucleophilic ring-opening of 1,2 epoxyhexane lab?
Saturated sodium bicarbonate solution to neutralize the acid
56
What was the product extracted from and into in the acid v base nucleophilic ring-opening of 1,2 epoxyhexane lab?
from the aqueous layer into diethyl ether
57
How was the drying agent removed in the acid v base nucleophilic ring-opening of 1,2 epoxygexane lab?
Decanting
58
What was used to wash the reaction mixture in the basic conditions in the acid v base nucleophilic ring-opening of 1,2 epoxygexane lab?
Saturated ammonium chloride to neutralize the base in solution
59
What drying agent was used in the acid v base nucleophilic ring-opening of 1,2 epoxygexane lab?
magnesium sulfate
60
What was used to characterize the product in the acid v base nucleophilic ring-opening of 1,2 epoxygexane lab?
Gas chromatography
61
How are mixtures separated in gas chromatography?
Based on each components affinity for the non-polar stationary phase versus the inert gas mobile phase (each component will exit column at different times)
62
What equation is used to ration peaks in gas chromatography?
% P = (A1/ (A1 + A2 + A3)) * 100
63
What compounds have longer retention times in the acid v base nucleophilic ring-opening of 1,2 epoxygexane lab?
polar
64
How are esters generally synthesized under Fisher conditions?
From a carboxylic acid and an alcohol under acidic conditions
65
According the Le Chatlier's principle, what will drive the reaction toward the products?
Increase concentration of alcohol or remove water as it is formed
66
All Fisher esterification reactions proceed via _____
microscope reversibility (the forward and reverse pathways in the mechanism are identical)
67
What was used for basification in the Fischer Esterification lab to neutralize the organic layer and what does it result in?
Sodium Bicarbonate (NaHCO3), resulting in the formation of CO2 which bubbled out of solution
68
What was used as the drying agent in the Fischer Esterification lab?
Sodium sulfate
69
Why are acid halides not able to be used for amide synthesis?
They are moisture sensitive and not fit for moisture rich environments
70
What is the catalyst in the amide synthesis lab?
Aluminum oxide (Al2O3)
71
Why is aluminum oxide used in the amide synthesis lab?
Allows for admiration of a carboxylic acid in high yields without having to use an acid halide
72
What type of extraction was used in the amide synthesis lab?
solid/liquid extraction
73
What was used to extract the product from the reaction mixture in the amide synthesis lab??
Ethyl acetate
74
Why is ethyl acetate used in the amide synthesis lab?
The unknown amine and aluminum oxide are not soluble in ethyl acetate; only the product goes into ethyl acetate
75
What was used to separate the ethyl acetate from precipitate in the amide synthesis lab?
gravity filtration
76
What was used to identify the final product in the amide synthesis lab?
Melting point determination
77
What is sodium borohydride used to reduce?
aldehydes, ketones, acyl halides, thiol esters, and imines will NOT reduce esters, amides, or carboxylic acids
78
What was the reducing reagent used in the reaction of an unknown ketone/aldehyde lab?
sodium borohydride (NaBH4)
79
What was used to run the reaction in the reaction of an unknown ketone/aldehyde lab?
reflux
80
What method of extraction was used in the reaction of an unknown ketone/aldehyde lab?
liquid/liquid extraction
81
What was used to extract the mixture from the aqueous layer in the reaction of an unknown ketone/aldehyde lab?
methylene chloride (goes to bottom)
82
What happens in the Wittig reaction?
Forms a double bond via reaction of a phosphorus ylide with an aldehyde or ketone
83
What is the by product of the witting reaction?
O double bond PPh3
84
What is added dropwise into the reaction in the wittig reaction lab?
sodium hydroxide resulting in formation of ylide
85
The aldehyde is ___ and the ylide is ____ in the wittig reaction lab?
hydrophobic/ hydrophilic
86
What was used as the drying agent in the wittig reaction lab?
Calcium Chloride
87
What was the product purified from using recrystallization in the wittig reaction lab?
1-propanol
88
Why is the product favored in the aldol condensation lab?
Due to conjugation throughout the molecule
89
What was added dropwise to the stirring solution of aldehyde and ketone
sodium hydroxide
90
What formed in the reaction vile during the aldol condensation lab?
white/yellow precipitate
91
What helped with crystallization in the aldol condensation lab?
ice bath
92
How were the crystals collected in the aldol condensation lab?
suction filtration
93
What were the crystals washed with in the aldol condensation lab?
DI water to neutralize residual sodium hydroxide
94
What was the product purified using recrystallization from in the aldol condensation lab?
ethanol
95
How were the crystals collected in the aldol condensation lab?
suction filtration
96
When do EAS reactions proceed quickly?
When strongly electron donating groups are attached to the ring
97
What was the electrophile formed from in the Friedel-Crafts Alkylation lab?
tertiary alcohol and a Bronsted acid catalyst
98
What was the catalyst in the Friedel-Crafts Alkylation lab?
sulfuric acid
99
The electrophile was generated ____ (in the reaction mixture) in the Friedel-Crafts Alkylation lab?
in situ
100
What happens after the electrophile is added in the Friedel-Crafts Alkylation lab?
benzene undergoes E1 elimination to reform aromaticity
101
How was the reaction quenched in the Friedel-Crafts Alkylation lab?
Addition of ice cold water to the reaction mixture (neutralizing acid catalyst)
102
What formed from the quenching of the reaction in the Friedel-Crafts Alkylation lab?
white precipitate
103

O Chem Reaction Mechanisms (2 decks)

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