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

O Chem 2 Lab Final Flashcards

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
Q

What was the ether extract used for in the conversion of carvone to carvacrol lab and why was it used?

A

Sodium Bicarbonate used to neutralize the acid

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25
Q

What was used to dry the product in the conversion of carvone to carvacrol lab?

A

Sodium sulfate (Na2SO4)

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26
Q

What peaks were changed in the IR of the conversion of carvone to carvacrol lab?

A

C-O double bond carbonyl changed for O-H stretch and arena peak/undertones

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27
Q

What is used to form an ether in Williamson-Ether synthesis?

A

An alcohol and alkyl halide under basic conditions

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28
Q

Why are primary alkyl halides typically used for Williamson Ether Synthesis?

A

The alkyl halide serves as the electrophile for an Sn2 reaction

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29
Q

What type of alkyl halide was used in the Williamson-Ether Synthesis lab?

A

Unknown primary Alkyl Bromide

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30
Q

What were the catalysts used in the Williamson-Ether Synthesis lab?

A

KOH (base catalyst) & TBAB (phase-transfer catalyst)

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31
Q

What does TBAB stand for in the Williamson-Ether Synthesis lab?

A

Tetra-N-butylammonium bromide

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32
Q

What does TBAB do in the Williamson-Ether Synthesis lab?

A

Phase transfer catalyst that works by helping ions cross between the organic and aqueous phase

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33
Q

What was used to run the reaction in the Williamson-Ether Synthesis lab and why?

A

Microwave reflux to speed up the reaction by holding the reaction at a constant temperature and pressure

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34
Q

What isolation method was used in the Williamson-Ether Synthesis lab?

A

Liquid/liquid extraction

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35
Q

What was used to extract the mixture in the Williamson-Ether Synthesis lab?

A

diethyl ether

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36
Q

What layer was the product in the Williamson-Ether Synthesis lab?

A

organic layer / washed with potassium hydroxide to remove impurities

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37
Q

What was used as the drying agent in the Williamson-Ether Synthesis lab?

A

sodium sulfate

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38
Q

What was used to purify the product in the Williamson-Ether Synthesis lab?

A

column chromatography to separate components of a mixture on a milligram-to-milligram scale

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39
Q

What is the mobile phase of the column chromatography in the Williamson-Ether Synthesis lab?

A

Methylene Chloride (DCM) (less polar)

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40
Q

What is the stationary phase of column chromatography in the Williamson-Ether Synthesis lab?

A

Silica gel (more polar)

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41
Q

What phase did the product remain in the Williamson-Ether Synthesis lab and why?

A

mobile phase because it is less polar than the highly polar stationary phase

42
Q

What stretch transition was seen in the Williamson-Ether Synthesis lab?

A

O-H stretch to C-O-C stretch

43
Q

What was used for characterization in the Williamson-Ether Synthesis lab?

A

Thin Layer Chromatography (TLC) used to check product formation and product purity

44
Q

What were the 3 spots on the TLC plate in the Williamson-Ether Synthesis lab?

A

4-bromophenol, unknown alkyl halide, and purified product

45
Q

What was the stationary phase of TLC in the Williamson-Ether Synthesis lab?

A

silica gel (polar) –> polar compounds bind to the silica gel and do not migrate to top of plate

46
Q

What was the mobile phase of TLC in the Williamson-Ether Synthesis lab?

A

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
Q

How do you calculate Retention factor?

A

Rf = distance from origin to spot / distance from origin to solvent front

48
Q

What side does the nucleophile attack on an epoxide in acidic conditions?

A

Most substituted

49
Q

What side does the nucleophile attack on an epoxide in basic conditions?

A

Least substituted

50
Q

Why was ammonium chloride used in the basic workup in the acid v base nucleophilic ring-opening of 1,2 epoxygexane lab?

A

To avoid ether cleavage (ethers cleave in strongly acidic conditions)

51
Q

What are the acidic reagents in the acid v base nucleophilic ring-opening of 1,2 epoxyexane lab?

A

H2SO4 & methanol

52
Q

What are the basic reagents in the acid v base nucleophilic ring-opening of 1,2 epoxyhexane lab?

A
  1. NaOCH3, methanol
  2. NH4Cl
53
Q

What was used to run the reaction in the acid v base nucleophilic ring-opening of 1,2 epoxyhexane lab?

A

Reflux

54
Q

What isolation method was used in the acid v base nucleophilic ring-opening of 1,2 epoxyhexane lab?

A

liquid/liquid extraction

55
Q

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?

A

Saturated sodium bicarbonate solution to neutralize the acid

56
Q

What was the product extracted from and into in the acid v base nucleophilic ring-opening of 1,2 epoxyhexane lab?

A

from the aqueous layer into diethyl ether

57
Q

How was the drying agent removed in the acid v base nucleophilic ring-opening of 1,2 epoxygexane lab?

A

Decanting

58
Q

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?

A

Saturated ammonium chloride to neutralize the base in solution

59
Q

What drying agent was used in the acid v base nucleophilic ring-opening of 1,2 epoxygexane lab?

A

magnesium sulfate

60
Q

What was used to characterize the product in the acid v base nucleophilic ring-opening of 1,2 epoxygexane lab?

A

Gas chromatography

61
Q

How are mixtures separated in gas chromatography?

A

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
Q

What equation is used to ration peaks in gas chromatography?

A

% P = (A1/ (A1 + A2 + A3)) * 100

63
Q

What compounds have longer retention times in the acid v base nucleophilic ring-opening of 1,2 epoxygexane lab?

A

polar

64
Q

How are esters generally synthesized under Fisher conditions?

A

From a carboxylic acid and an alcohol under acidic conditions

65
Q

According the Le Chatlier’s principle, what will drive the reaction toward the products?

A

Increase concentration of alcohol or remove water as it is formed

66
Q

All Fisher esterification reactions proceed via _____

A

microscope reversibility (the forward and reverse pathways in the mechanism are identical)

67
Q

What was used for basification in the Fischer Esterification lab to neutralize the organic layer and what does it result in?

A

Sodium Bicarbonate (NaHCO3), resulting in the formation of CO2 which bubbled out of solution

68
Q

What was used as the drying agent in the Fischer Esterification lab?

A

Sodium sulfate

69
Q

Why are acid halides not able to be used for amide synthesis?

A

They are moisture sensitive and not fit for moisture rich environments

70
Q

What is the catalyst in the amide synthesis lab?

A

Aluminum oxide (Al2O3)

71
Q

Why is aluminum oxide used in the amide synthesis lab?

A

Allows for admiration of a carboxylic acid in high yields without having to use an acid halide

72
Q

What type of extraction was used in the amide synthesis lab?

A

solid/liquid extraction

73
Q

What was used to extract the product from the reaction mixture in the amide synthesis lab??

A

Ethyl acetate

74
Q

Why is ethyl acetate used in the amide synthesis lab?

A

The unknown amine and aluminum oxide are not soluble in ethyl acetate; only the product goes into ethyl acetate

75
Q

What was used to separate the ethyl acetate from precipitate in the amide synthesis lab?

A

gravity filtration

76
Q

What was used to identify the final product in the amide synthesis lab?

A

Melting point determination

77
Q

What is sodium borohydride used to reduce?

A

aldehydes, ketones, acyl halides, thiol esters, and imines

will NOT reduce esters, amides, or carboxylic acids

78
Q

What was the reducing reagent used in the reaction of an unknown ketone/aldehyde lab?

A

sodium borohydride (NaBH4)

79
Q

What was used to run the reaction in the reaction of an unknown ketone/aldehyde lab?

A

reflux

80
Q

What method of extraction was used in the reaction of an unknown ketone/aldehyde lab?

A

liquid/liquid extraction

81
Q

What was used to extract the mixture from the aqueous layer in the reaction of an unknown ketone/aldehyde lab?

A

methylene chloride (goes to bottom)

82
Q

What happens in the Wittig reaction?

A

Forms a double bond via reaction of a phosphorus ylide with an aldehyde or ketone

83
Q

What is the by product of the witting reaction?

A

O double bond PPh3

84
Q

What is added dropwise into the reaction in the wittig reaction lab?

A

sodium hydroxide resulting in formation of ylide

85
Q

The aldehyde is ___ and the ylide is ____ in the wittig reaction lab?

A

hydrophobic/ hydrophilic

86
Q

What was used as the drying agent in the wittig reaction lab?

A

Calcium Chloride

87
Q

What was the product purified from using recrystallization in the wittig reaction lab?

A

1-propanol

88
Q

Why is the product favored in the aldol condensation lab?

A

Due to conjugation throughout the molecule

89
Q

What was added dropwise to the stirring solution of aldehyde and ketone

A

sodium hydroxide

90
Q

What formed in the reaction vile during the aldol condensation lab?

A

white/yellow precipitate

91
Q

What helped with crystallization in the aldol condensation lab?

A

ice bath

92
Q

How were the crystals collected in the aldol condensation lab?

A

suction filtration

93
Q

What were the crystals washed with in the aldol condensation lab?

A

DI water to neutralize residual sodium hydroxide

94
Q

What was the product purified using recrystallization from in the aldol condensation lab?

A

ethanol

95
Q

How were the crystals collected in the aldol condensation lab?

A

suction filtration

96
Q

When do EAS reactions proceed quickly?

A

When strongly electron donating groups are attached to the ring

97
Q

What was the electrophile formed from in the Friedel-Crafts Alkylation lab?

A

tertiary alcohol and a Bronsted acid catalyst

98
Q

What was the catalyst in the Friedel-Crafts Alkylation lab?

A

sulfuric acid

99
Q

The electrophile was generated ____ (in the reaction mixture) in the Friedel-Crafts Alkylation lab?

A

in situ

100
Q

What happens after the electrophile is added in the Friedel-Crafts Alkylation lab?

A

benzene undergoes E1 elimination to reform aromaticity

101
Q

How was the reaction quenched in the Friedel-Crafts Alkylation lab?

A

Addition of ice cold water to the reaction mixture (neutralizing acid catalyst)

102
Q

What formed from the quenching of the reaction in the Friedel-Crafts Alkylation lab?

A

white precipitate

103
Q
A

O Chem Reaction Mechanisms (2 decks)

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