Organic Lab Final – Flashcards
question
What is a Qualitative Test?
answer
A test reaction that indicates a reaction took place. Positive test includes color change, precipitate or some other observable change.
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Br2 is toxic. Pyrimidium Tribromride (PBP) is safer. What color change would you see with an alkene?
answer
Orange-Brown to colorless
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Will PBP work with benzene or alkane compounds?
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No reaction
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KMnO4 Color change? What conditions needed?
answer
Purple oxidizing agent to colorless 2% KMnO4 & Low Temp
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Will KMnO4 work benzene or alkane compounds?
answer
No reaction
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Draw Pyridinium Tribromide
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Benzene with N(+) in a = Bond +Br3(-)
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SN1 Substrate Reactivity
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3>2>1>CH3 So a stable carbocation can be formed
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SN1 Leaving Group
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Cl-, Br-, I-, weak bases, OH-
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SN1 Nucleophile
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Weak Typically neutral molecules
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SN1 Solvent
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Polar protic
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SN1 Reaction mechanism
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2 Step: Carbocation then nucleophillic attack
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SN1 Rate Law
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1st order: Rate=k[substrate]
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SN1 steriochemistry
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Chiral -> Racemic Mixture
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SN2 Substate reacttivity
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Ch3>1>2>3 Nucleophile needs unhindered access to central carbon
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SN2 Leaving Group
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Cl-, Br-, I-, weak bases
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SN2 Nucleophile
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Strong(charged) nucleophile
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SN2 Solvent
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Polar aprotic [H is not attached to electroneg element], low temperature DMSO THF Acetone
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SN2 Reaction mechanism
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1 step
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SN2 Rate law
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2nd order Rate=k[substrate][nucleophile]
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SN2 Stereochemistry
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Inversion of R/S
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What did you do in the SN2 Lab?
answer
Tried to form 1-bromobutane from 1-butanol via SN2. 1-butanol +HBr was cooled with H2SO4 then boiled and condensed. Upper aqueous layer extracted & washed with with water, then NaHCO3 then water. CaCl2 was added to product.
question
Why wash with NaHCO3? SN2
answer
Sodium bicarbonate can be used as a wash to remove any acidic impurities from a "crude" liquid, producing a purer sample. NaOH neutralizes any traces of H2SO4 in the organic product layer.
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Why wash with H2O? SN2
answer
Washing with water simply removes any unreacted H2SO4 molecules.
question
What visual evidence can be gained to determine that 1-butanol is being converted to 1-bromobutane?
answer
Assuming that the reaction is done as an aqueous reaction, formation of 1-bromobutane would result in the formation of a second liquid layer because 1-bromobutane is not very soluble in water. 1-bromobutane has a higher density of water so it was always on the bottom.
question
Protonation of OH by HBr is _________ reaction
answer
Acid Base
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Procedure for dehydrating cyclohexanol
answer
H3PO4+ Cyclohexanol +H2SO4 - heated Two layers formed, removed bottom because aqueous was on bottom CaCl was added to product.
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E1 Rate Law
answer
Rate= [substrate]
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E1 Substrate
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Benzylic>3>2
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E1 Base
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weak
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E1 Leaving Group
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very important Cl-, Br-, I-, weak bases
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E1 Solvent
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polar protic water, alcohol, formic acid, hF, ammonium
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E2 Rate Law
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Rate=[substrate][Base]
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E2 Substrate
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1>2>>3
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E2 Base
answer
Strong Base Usually anions that are very sterically hindered, preventing them from attacking as nucleophiles Tert-butyl Lithium : tBuLi (also written as (CH3)3CLi) PotassiumTert-butoxide : KOtBu (also written as (KOC(CH3)3) Lithium Diisopropylamide : LDA (acronym) (also written as LiN(CH(CH3)2)2)
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E2 Leaving Group
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important Cl-, Br-, I-, weak bases
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E2 Solvent
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high temp
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Nitration of methyl benzoate Reaction
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1) Weaker Acid (HO-N=O-O-) attack Stronger acid (HO-S=O=O-OH) 2) water breaks off 3) nitronium ion is formed 4) Benzoate attacked Nitronium 5) 2 Resonase 6) H2O grabs H to restore aromaticity
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What kind of reaction is nitration of methyl benzoate?
answer
Electrophillic Aromatic Substitution
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What is the major/minor product of methyl benzoate nitration?
answer
Ortho: Major Para & meta: Minor
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How should acids be added together?
answer
Stronger acid to weaker acid
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Steps for nitrating methyl benzoate?
answer
Chilled nitric acid and sulfuric acid Acids were added to methyl benzoate and chilled mixture was vaccum filtrated washed with 10 ml of water then recrystalized with ethanol
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Steps of adol reaction to make dibenzalacetone
answer
1. Ethanol and NaOh mixed and cooled 2. Benzzaldehyde and actone mixed. Both 1 & 2 mixed vacume filtrated recrystalized with ethanol
question
enolating is ________ reaction and is faster than ___________
answer
acid base nucleophillic addition
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Example of Polar solvent
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Water (aqueous)
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Example of Nonpolar solvent
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Ether, hydrocarbon (organic), CH2Cl2(Less dense than water)
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polar and nonpolar solvent are ____
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mutually immisable (dont dissolve each other)
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What is emusion? When does it happen
answer
phase where substance forms small particles Happens with intermediate polarites
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How do you increase polarity?
answer
Add ionic compound
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Where is the hydrocarbon usually located and why?
answer
USually above aqueous because it is less dense
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What does a rotavapor do?
answer
extracts volitile solvent as it rotates
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p-tert-butylphenol
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Methyl is para tho
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p-toulic acid
answer
methyl is para
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What did we do in separating acids and neutral compound lab?
answer
Premixed acetanilide, p-tert-butylphenol and p-toluic acid in tertbutyl methyl ether. 1) NaHCO3 was added to separating funnel, aqueous layer was drained 2) NaOH was added to ether, aqueous layer drained A) 1) & 2) was reacted with HCl to precipitate p-toluic acid and filtered tertbutyl methyl ether was reacted with anhydrous na2so4 to remove water
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Why was NaHCO3 added? Lab 4
answer
to remove any p-toluic acid
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What was NaOH added? Lab 4
answer
remove any p-tert-butylphenol
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Why does para-toulic acid react with NaHCO3?
answer
strong to weak acid favorable
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What is the difference between extraction and washing?
answer
Extraction and Washing are is the processes of selectively removing a compound of interest from a mixture using a solvent. Extract:you remove a product from the mixture, leaving the impurities behind. Wash: you remove unwanted impurities from a mixture, leaving the product in the original solution.
question
Why is the NaOh extract heated before acidification?
answer
To remove any trace of tert-butyl methyl ether that can inhibit crystilzation of phenol.
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What two visible evidences of reaction will you see when you acidify the NaHCO3 extract with HCl solution?
answer
Foaming Precipate of p-toluic acid
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In which layer would p-toluic acid be more soluble if p-toluic acid added to a two-layer mixture of tert-butyl methyl ether and water?
answer
tert-butyl methyl ether
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How do you know when your done adding acid?
answer
No new percipitate or pH stays the sam
Unlock all answers in this set
Unlock answersquestion
What is a Qualitative Test?
answer
A test reaction that indicates a reaction took place. Positive test includes color change, precipitate or some other observable change.
question![]()
Br2 is toxic. Pyrimidium Tribromride (PBP) is safer. What color change would you see with an alkene?
answer
Orange-Brown to colorless
question
Will PBP work with benzene or alkane compounds?
answer
No reaction
question![]()
KMnO4 Color change? What conditions needed?
answer
Purple oxidizing agent to colorless 2% KMnO4 & Low Temp
question
Will KMnO4 work benzene or alkane compounds?
answer
No reaction
question
Draw Pyridinium Tribromide
answer
Benzene with N(+) in a = Bond +Br3(-)
question
SN1 Substrate Reactivity
answer
3>2>1>CH3 So a stable carbocation can be formed
question
SN1 Leaving Group
answer
Cl-, Br-, I-, weak bases, OH-
question
SN1 Nucleophile
answer
Weak Typically neutral molecules
question
SN1 Solvent
answer
Polar protic
question
SN1 Reaction mechanism
answer
2 Step: Carbocation then nucleophillic attack
question
SN1 Rate Law
answer
1st order: Rate=k[substrate]
question
SN1 steriochemistry
answer
Chiral -> Racemic Mixture
question
SN2 Substate reacttivity
answer
Ch3>1>2>3 Nucleophile needs unhindered access to central carbon
question
SN2 Leaving Group
answer
Cl-, Br-, I-, weak bases
question
SN2 Nucleophile
answer
Strong(charged) nucleophile
question![]()
SN2 Solvent
answer
Polar aprotic [H is not attached to electroneg element], low temperature DMSO THF Acetone
question
SN2 Reaction mechanism
answer
1 step
question
SN2 Rate law
answer
2nd order Rate=k[substrate][nucleophile]
question
SN2 Stereochemistry
answer
Inversion of R/S
question
What did you do in the SN2 Lab?
answer
Tried to form 1-bromobutane from 1-butanol via SN2. 1-butanol +HBr was cooled with H2SO4 then boiled and condensed. Upper aqueous layer extracted & washed with with water, then NaHCO3 then water. CaCl2 was added to product.
question
Why wash with NaHCO3? SN2
answer
Sodium bicarbonate can be used as a wash to remove any acidic impurities from a "crude" liquid, producing a purer sample. NaOH neutralizes any traces of H2SO4 in the organic product layer.
question
Why wash with H2O? SN2
answer
Washing with water simply removes any unreacted H2SO4 molecules.
question
What visual evidence can be gained to determine that 1-butanol is being converted to 1-bromobutane?
answer
Assuming that the reaction is done as an aqueous reaction, formation of 1-bromobutane would result in the formation of a second liquid layer because 1-bromobutane is not very soluble in water. 1-bromobutane has a higher density of water so it was always on the bottom.
question
Protonation of OH by HBr is _________ reaction
answer
Acid Base
question
Procedure for dehydrating cyclohexanol
answer
H3PO4+ Cyclohexanol +H2SO4 - heated Two layers formed, removed bottom because aqueous was on bottom CaCl was added to product.
question
E1 Rate Law
answer
Rate= [substrate]
question
E1 Substrate
answer
Benzylic>3>2
question
E1 Base
answer
weak
question
E1 Leaving Group
answer
very important Cl-, Br-, I-, weak bases
question
E1 Solvent
answer
polar protic water, alcohol, formic acid, hF, ammonium
question
E2 Rate Law
answer
Rate=[substrate][Base]
question
E2 Substrate
answer
1>2>>3
question
E2 Base
answer
Strong Base Usually anions that are very sterically hindered, preventing them from attacking as nucleophiles Tert-butyl Lithium : tBuLi (also written as (CH3)3CLi) PotassiumTert-butoxide : KOtBu (also written as (KOC(CH3)3) Lithium Diisopropylamide : LDA (acronym) (also written as LiN(CH(CH3)2)2)
question
E2 Leaving Group
answer
important Cl-, Br-, I-, weak bases
question
E2 Solvent
answer
high temp
question![]()
Nitration of methyl benzoate Reaction
answer
1) Weaker Acid (HO-N=O-O-) attack Stronger acid (HO-S=O=O-OH) 2) water breaks off 3) nitronium ion is formed 4) Benzoate attacked Nitronium 5) 2 Resonase 6) H2O grabs H to restore aromaticity
question
What kind of reaction is nitration of methyl benzoate?
answer
Electrophillic Aromatic Substitution
question
What is the major/minor product of methyl benzoate nitration?
answer
Ortho: Major Para & meta: Minor
question
How should acids be added together?
answer
Stronger acid to weaker acid
question
Steps for nitrating methyl benzoate?
answer
Chilled nitric acid and sulfuric acid Acids were added to methyl benzoate and chilled mixture was vaccum filtrated washed with 10 ml of water then recrystalized with ethanol
question
Steps of adol reaction to make dibenzalacetone
answer
1. Ethanol and NaOh mixed and cooled 2. Benzzaldehyde and actone mixed. Both 1 & 2 mixed vacume filtrated recrystalized with ethanol
question
enolating is ________ reaction and is faster than ___________
answer
acid base nucleophillic addition
question
Example of Polar solvent
answer
Water (aqueous)
question
Example of Nonpolar solvent
answer
Ether, hydrocarbon (organic), CH2Cl2(Less dense than water)
question
polar and nonpolar solvent are ____
answer
mutually immisable (dont dissolve each other)
question
What is emusion? When does it happen
answer
phase where substance forms small particles Happens with intermediate polarites
question
How do you increase polarity?
answer
Add ionic compound
question
Where is the hydrocarbon usually located and why?
answer
USually above aqueous because it is less dense
question
What does a rotavapor do?
answer
extracts volitile solvent as it rotates
question
p-tert-butylphenol
answer
Methyl is para tho
question![]()
p-toulic acid
answer
methyl is para
question
What did we do in separating acids and neutral compound lab?
answer
Premixed acetanilide, p-tert-butylphenol and p-toluic acid in tertbutyl methyl ether. 1) NaHCO3 was added to separating funnel, aqueous layer was drained 2) NaOH was added to ether, aqueous layer drained A) 1) & 2) was reacted with HCl to precipitate p-toluic acid and filtered tertbutyl methyl ether was reacted with anhydrous na2so4 to remove water
question
Why was NaHCO3 added? Lab 4
answer
to remove any p-toluic acid
question
What was NaOH added? Lab 4
answer
remove any p-tert-butylphenol
question
Why does para-toulic acid react with NaHCO3?
answer
strong to weak acid favorable
question
What is the difference between extraction and washing?
answer
Extraction and Washing are is the processes of selectively removing a compound of interest from a mixture using a solvent. Extract:you remove a product from the mixture, leaving the impurities behind. Wash: you remove unwanted impurities from a mixture, leaving the product in the original solution.
question
Why is the NaOh extract heated before acidification?
answer
To remove any trace of tert-butyl methyl ether that can inhibit crystilzation of phenol.
question
What two visible evidences of reaction will you see when you acidify the NaHCO3 extract with HCl solution?
answer
Foaming Precipate of p-toluic acid
question
In which layer would p-toluic acid be more soluble if p-toluic acid added to a two-layer mixture of tert-butyl methyl ether and water?
answer
tert-butyl methyl ether
question
How do you know when your done adding acid?
answer
No new percipitate or pH stays the sam
