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33 Cards in this Set
- Front
- Back
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Tetraphenylphthalic Anhydride
IR spectroscopy |
Aromatic (C-H): 2850-3100
Anhydride: 1630-1780 Aromatic (C=C): 1450-1650 C-O-C: 1100-1200 |
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Tetraphenylphthalic Anhydride
NMR spectroscopy |
Several peaks 6.5-8.5
From individual hydrogens on aromatic compound |
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Tetraphenylphthalic Anhydride
UV spectroscopy |
Phenol group: 280
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Tetraphenylphthalic Melting Point:
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289-290
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Dilantin
IR spectroscopy |
N-H bond : 3200
C=O bond: 1700-1800 C=C bond: 1450-1650 C-H bond: 2850-3100 |
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Dilantin
NMR spectroscopy |
Aromatic group (with keto): 6.5-8
N-H bond: 1-5 Aldehyde (with enol): 9.5-10.5 Phenol group: 4.5-7.7 |
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Dilantin
UV spectroscopy |
Max peak 280
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4-tert-butylcyclohexanol
IR spectroscopy |
Alcohol: 3200-3500
Alkyl: 2700-3300 Butyl: 1385-1395 |
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4-tert-butylcyclohexanonol
NMR spectroscopy |
CH3 : 07-1.3
CH2 : 1.2-1.6 CH : 1.4-1.8 OH : 3.4-4.0 -- 3.5 ppm trans -- 4.0 ppm cis |
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4-tert-butylcyclohexanonol
Mass spectroscopy |
M+ 154
m/z 57 (responsible for tertbutyl) |
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The conversion of benzaldehyde to benzoin is frequently referred to as the benzoin condensation and is catalyzed by the cyanide ion. Suggest a reason for using thiamine instead.
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Biochemical reactions in the body use thiamine.
Cyanide is toxic even in small amounts. |
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How does the hydroxide ion help to catalyze the conversion of benzaldehyde to benzoin in the presence of thiamine?
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Catalyzes the conversion. Because deprotonates the thiamine ring and creates a nucleophilic carbanion to react in the condensation
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During TLC benzoin has a smaller Rf value than benzil. Which compound moves more rapidly on the TLC plate? What is the structural feature responsible for this observation?
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Benzil travels quicker then benzoin.
Benzoin is an alcohol and more polor (lower position) |
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Suggest a function for KOH in the synthesis of 5,5-diphenylhydratoin.
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When urea is added to benzil, the nuclephilic attack by the nitrogen atom causes a loss of a H atom. KOH must be present as a catalyst to cause the rearrangement to occur.
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Which isomer, cis or trans, of 4-tert-butylcyclohexanol was formed in greater yield in the reaction. Explain why.
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trans
There was a large signal at 3.5 and there case a greater number of peaks than at the cis(4.0) |
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LiAlH[OC(CH3)3] is much milder reducing agent than LiAlH4. Why?
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Because LiAlH[OC(CH3)3] is a bulky reducing agent, and a more hindered molecule.
LiAlH4 is a very small unhindered molecule. |
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Why is 95% ethanol not a suitable solvent for reductions using LiAlH4 but works well with NaBH4 as a reductant.
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LiAlH4 reacts violently with protic solvents and must be used in dry aprotic solvents.
NaBH4 is milder and is not a strong H donor. |
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Oxidations with sodium hypochlorite are refered to as green chemistry, why?
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Because the by products of the reaction are salt and water, which is harmless
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What is the thermodyndamic driving force for the loss of CO from the intermediate in step 2 to form the product dimethyl tetraphenylphthalate?
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heat
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Why is HCL added as the final step in the synthesis of tetraphenylphthalic acid?
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Because the base has cause carboxilic acid to deprotanate towards equilibrium. The addition of HCl causes a shift in the equalibrium to make the final product.
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Suggest two reasons why the reagents must be dry and the presence of water be avoided in the synthesis of the anhydride.
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Because anhydride is very reactive and is combustible. Acetic anhydride reacts readily with water to form acetic acid. May cause irritation of body tissues. The acetic anhydride reacts with water to yield acetic acid.
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During the oxidation of benzoin, what species is the reductant?
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benzoin
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2-propanol, rather than sodium bisulfite, can be used to destroy excess sodium hypochlorite. What organic compound would be formed by this reaction?
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acetone
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Melting point of Dilantin:
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295-298
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Benzoin rxn conditions:
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Ice water bath
Heated while refluxing Cooled |
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Benzil rxn conditions:
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Apparatus allowed NO2 trapped in ice water bath while heating mixture.
TLC to see if complete Cooled |
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Dilantin rxn conditions:
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Heated while refluxing
Percipaitate removed pH 4-5 Cooled |
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Ox of 4-tert-butylcyclohexanol rxn conditions:
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3 neck flask with cold water condenser and separatory funnel while stirring
TLC to see complete Stop stirring Cooled to room temp Dried over anhydrous MgSO4 Distillation on hot water bath Cooled |
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Red of 4-tert-butylcyclohexanone
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Cool water bath and warm water bath to maintain temp bw 25-35
TLC for complete Heated Cooled to room temp Ice-water bath Separatory funnel Dried over MgSO4 |
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Step 1 Tetraphenylphthalic Anhydride rxn conditions:
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Heated and stirred
Cooled to 100 Cooled to 80 and put in water bath Cold-water bath and stirring |
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Step 2 Tetraphenylphthalic Anydride rxn conditions:
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Flask with cold water condensor
Heated rapidly to reflux Gentle reflux Cool to 80 Cooled to room temperature Ice water bath |
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Step 3 Tetraphenylphthalic Anhydride rxn conditions:
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Heated while refluxing
Cooled to room temp pH below 2 Cooled in ice water bath Vacuum filtrated Dried in oven to next class period |
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Step 4 Tetraphenylphthalic Anhydride rxn conditions:
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Cold water condenser with calcium chloride drying tube - Heated while refluxing
Cool to room temp Ice water bath Vacuum filtrated Dried in an oven |
