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Orgo Chem Lab Exam 1

Terms in this set (54)

terpenes are composed from
5-carbon isoprene units
citrus oils are primarily
D-limonene
heating in presence of acid converts limonene to
terpinene
terpenes are polar or non polar organics that are soluble in organic solvent
non-polar
what organic solvents are terpenes soluble in
pentane, liquid CO2
in gas chromatography analyte is injected into a column, where it is in equilibrium between a
mobile gas phase (helium) and stationary liquid phase
in gas chromatography the gas/liquid equilibrium is related to boiling point, but is NOT a
direct measurment of BP
how are peaks recorded in gas chromatography
detector signals when compound exits the column
factors that affect retention times in GC
carrier gas flow rate, length and size of column, nature and amount of liquid phase, temperature of the column, structure and functional groups in compound
what are immiscible liquids
compound has different solubilities in two liquid phases
steps in a typical aqueous/organic extraction
dissolve mixture in H2O add CHCl3, mix, separate layers
true or false organic compounds which are not converted to salts will stay in the organic phase
true
change solubility of selected organic compound in a mixture by
converting it to a salt
Extraction experiment step 1
Dissolve mixture of p-toluic acid, p-tert-butylphenol, and acetanilide in tert-butyl methyl ether, pour into separatory funnel
extraction experiment: mixture of p-toluic acid, p-tert-butylphenol, and acetanilide in tert-butyl methyl ether, pour into separatory funnel then what
Add aqueous base (NaHCO3 or NaOH), invert, vent gas that forms
in the extraction experiment, acidic components turned into __ and go in to the ___ phase
salt, aqueous
how do you neutralize the aqueous phase in the extraction experiment
HCl (vacuum filtration to collect)
how do you isolate the organic phase in the extraction experiment
drying agent Na2SO4 then rotovap
how do you recrystalize p-toluic acid
dissolve in minimum amount of hot ethanol, cool, vacuum filtrate
in H NMR down field is which way and up field is which way
left (big numbers), right (small numbers)
in H NMR electronegative atoms shift in which direction
left
porphyrins are composed of
4 pyyrole units
how are Rf values determined
distance traveled by compound divided by distance traveled by solvent
in mixtures the most volatile liquid changes to gas
first
when is simple distillation used
when two substances have boiling points which differ by 80 °C or more (separation is easy)
when is fractional distillation used
usually required when two substances have boiling points within 25 °C of each other (separation is difficult)
after several cycles, the material at the top of the fractionating column is mostly the___ boiling component
lower
cyclohexanol to adipic acid green chemistry
no fumes, no waste, no extra steps, reusable catalyst
ylides can only be made fromalkyl halides capable of
SN2
why is liquid CO2 used for terpene extraction
non flammable, readily available, non toxic, reusable, easy to remove from product
p-toluic acid is converted to a salt by
aqueous sodium bicarbonate (NaHCO3) or sodium hydroxide (NaOH)
p-tert butylphenol is converted to a salt by __ but not ___
NaOH, NaHCO3
can acetanilide be converted to a salt
no (neutral functional group stays in organic phase)
using sequential extraction in experiment 2 of extraction, name the steps
aqueous NaHCO3, then aqueous NaOH
describe the p-toluic isolation
to NaHCO3 extracts add HCl dropwise (neutralizes NaHCO3) until ph <3 and vacuum filtrate
describe acetanilide isolation
add Na2SO4, gravity filtrate, rotovap
unlike alkenes, benzene and aromatic heterocyles undergo ___ reactions instead of ___ reactions
substitution, addition
in synthesis of tetraphenylporphyrin electrophilic aromatic substitution reactions on ___ synthesizes it in the gas phase (purified by column chromatography)
pyrrole
for Tetraphenylporphyrin experiment what are the green principles
minimized use of hazardous materials and solvents (requires no additional reagents or solvents and air is used as oxidant)
for TLC of tetraphenylporphyrin what was the solvent
7:1 PE/EA
how do you purify tetraphenylporphyrin
column chromatography
what is the purpose of a UV spectrum
calculate the concentration of product, evidence both confirm identity and purity
dehydration of cyclohexanol is what type of mechanism
E1
for cyclohexanol to adipic acid, why is phosphoric acid used instead of sulfuric acid
less reactive and less corrosive (less hazardous)
what type of distillation was used for dehydration of cyclohexanol
fractured
adipic acid is important for the synthesis of
nylon
what is wrong with using nitric acid for synthesis of adipic acid
highly corrosive, violent reactions, release greenhouse gas, metal oxide waste
how can the oxidative cleavage in alkenes in experiment cyclohexanol to adipic acid be made catalytic (avoid waste)
sodium tungstate (catalyst) with hydrogen peroxide ( recycles metal oxides back into tungstate and byproduct of H2O2 is water and reagents soluble in water)
green chemistry of cyclohexanol to adipic acid
minimal waste, no extra steps, recyclable catalytic
how is the crude adipic acid recrystalized
minimal amount of water
The Wittig reaction provides an invaluable method for the conversion of an ___ to ___
aldehyde or ketone, olefin
how do you form triphenyl(4-pyridylmethyl)phosphonium chloride (1) that will form the ylide
4-pyridylmethyl chloride and triphenylphosphine (limiting reagent)
Because the ylide is very reactive it is generated in the presence of
4-pyr-CHO by treatment of the phosphonium salt with a strong base (NaOH) to generate the alkene
once the organic layer is removed in the witting reaction what do you do with the aqueous layer in the separatory funnel
neutralize acidic water by adding Na2CO3 collect via vacuum filtration
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