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32 Cards in this Set
- Front
- Back
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What are the various substances used to remove acids and bases in extraction?
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The HCl is used to remove bases
The NaOH is used to remove acids The NaHCO3 is used to remove carboxylic acids (Strong organic acids) |
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What do you want in extraction
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You are looking for the ether layer
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What are the exceptions in extractions
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Long hydrocarbons can't be extracted
Alcohols with 5 or less carbons always get extracted |
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What happens to the vapor pressure in extractions between the original solvent and the new solvent
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The vapor pressures are added
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What is occuring during distilation (what property is used to separate)
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The boiling point of substances
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What process is used to separate diasteromers
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Fractional distilation
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What is used to separate constitutional isomers
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Simple distilation
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What leaves first the lower or higher boiling point in distilation
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The lower boiling point
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What are two processes which use polarity
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Extraction and TLC
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Is TLC better for isolation or separation
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Separating
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Do polar molecules move higher or lower in TLC
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Lower
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Why do polar molecules move lower in TLC
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The polar molecules move with the polar stationary phase
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What chromatography is good for isolation
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Column chromatography
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How does column chromatography work, what is collect last?
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Polar is collected last
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What is Rf
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This is the ratio to front value, the ratio to front is - the substance that moved / distance front moved
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How does gas chromatography work
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It separates based on volaties
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In gas chromatography what will take longer
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Polar and less volatile compounds
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What is the way to separate enantiomers
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Resolution
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When is UV Spec used
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When evaluating conjugated systems
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What are two important numbers that should be remembered in IMR
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1700- C=O
3400ish and broad OH |
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Describe the 4 rules in proton nmr
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The signals represent each nonequivalent proton
The chemical shift will then show the environment of proton Integration tells how many prootons in each set in the molecule Splitting, split up based on the number of hydrogens (different non-equivalent) (n+1) Splitting |
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Describe how chemical shift works
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Downfield means, deshilded, to the left, less electrons but it is deshielded so next to an electronegative. Also the more (saint) s charachter in C-H bond more deshilded
Upfield, shieled, more electrons, less electronegative |
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A peak in the 6-8 region usually means that you have what
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A benzene
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How does acid and bases affect proton NMR
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They can cause a downfield trend, the nitrogen and oxygen make the downfield
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In a Cnmr what does a taller peak correspond to
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More Hydrogens
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Is integration or splitting seen in Cnmr
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No
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As electron density is increased NMR both C and H are you deshilded or shielded
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You are are shielded
Remember negative people (electronegtive) will not be your shield |
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What peak on proton NMR is a response to 3000
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A C-OH
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What is represented in a stretch from 2100-2600 peak.
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This is a C TRIPLE TO C
OR A C TRIPLE TO N. |
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How does the Gas Chromatography work, what will come out faster?
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The more volatile will emerge from the column fast and the less volatile will emerge slower.
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How does UV Spectroscopy work
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Conjugated systems absorb visible light, everything else absorbs UV
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Describe how hybirdization, En, Electrons, Acidity, and H-bonding effect chemical shift?
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En will make more deshielded
Electrons will make shield Greater S-orbital character will be more deshielded |
