Lab Final Chem 228
know mechanism for electrophilic substitution
**
look at what sunscreen compounds look like **
**
practice resonance with electron donating and withdrawing**
**
what are the two types of ultraviolet light
UVA and UVB (and UVC which typically gets absorbed in the atmosphere)
what are some examples of things with UVA and UVB
UVA- psychadelic posters UVA does penetrate glass UVB does (UVB causes tanning)
what do lah and nabh4 generally yield
a mixture of products
what kind of solvent do you use in a uv vis test
a sample that does not absorb above 200 nm (isopropyl alcohol) + cuvette made of pure silicon dioxide or polymethyl methacrylate (PMMA)
whats a positive test for tollens test
a silver mirror
what is the only aldehyde to give positive iodoform test
acetaldehyde
what helps esters and amides react
acidic and basic conditions (saponification)
how do you hydrolyze benzoyl chloride and ammonolyze benzoyl chloride
add benzoyl chloride to water and cool the solution and then collect by filtration add benzoyl chloride to ammonium hydroxide and pour into water, and collect benzamide by filtration
procedural steps for aromatic substi.
add methyl benzoate to sulfuric acid add sulfuric and nitric accids allow it to warm and stir pour over ice and collect solid wash with water and methanol
when making the tertiary alcohol, the reaction mixture was mixed with sodium chloride
decreases the solubility of the organic product in water (crowds water molecules)
what does nmr (nuclear magnetic resonance spec) measure
detects transitions between energy states of nuclei
how do laundry detergents make clothes white
detergents yellow clothing but blue compound is added to coat to make it appear white in visible light
how do you find concentration of A compared to concentration of B
divide them out and multiply by 100
what are the transition states in aromatic subst.
hydrogen leaving is second highest, and E adding is highest and E and H added on together is intermediate
what does the iodoform (haloform) test do
identifies methyl ketones
what can happen with aldehydes in air
it can be oxidized to a carboxylic acid
why will phenol react with 2,4 DNP
it has a tautomer resonance
what does the schiffs test do
it takes advantage of the fact that all aldehydes and ketones react with sulfur dioxide and distinguishes between aliphatic and aromatic aldehydes aromatic does not react and aliphatic turns purple ketones and aromatic take a long time
lah and nabh
lah-3 to a 1 nabh-2 to a 1
what happens if the glassware is not properly dried prior to the reaction
less ester is produced
what happens if the lid is left off the anhydrous alcohol bottle
less ester is produced
what can having a phenol or alcohol in the reaction due
lower the yield bc robs first equivalent grignard is fundamentally a base
what will decrease effectiveness of grignard
magnesium ribbon was not wiped and the glassware was not dried
why was the solution of benzoic acid and methanol heated on a steam bath in the derivatives of carboxylic acids lab
methanol which is a reagent and solvent is flammable
what is the mechanism of the iodoform reaction
methyl gets its h's ripped off by base and iodine added on. this complex hops away once OH adds and then grabs the H off the alcohol so its a deprotonated carboxylic acid. ChI3 is bright yellow
what are absorptions for substituated aromatics
mono: 770-715 1,2-disub: 770-730 1,3-disub: 820-760 1,4-disub: 870-800 1,2,3-trisub: 700--750 1,2,4: 850-800 1,3,5: 910-830
what happens if a drying agent is added to the reaction flask (drawing out water product
more ester is produced
what happens if an excess of methanol is used
more ester is produced
mechanism of 2,4 DNP
nitrogen adds to carbonyl and O gets minus charge O gets protonated twice and water leaves N forms double bond
what is the mechanism of the 2,4 DNP
nucleophilic nitrogen added to carbonyl and gives low ph
how can you tell between oh and ketone in camphor reduction
oh broad stretch and 1680 long stretch mixture: oh stretch and long stretch next to it plus 1680
what is SPF
the amount of sun protection a product will offer written in minimum erythemal dose or the amount of time one can stay in the sun before getting sunburn spf= med for skin with sunscreen/ med for skin without sunscreen
What does UV vis measure
the electronic transitions of conjugated π-systems and provides information about the length and structure of the conjugated part of a molecule.
why must you use excess
the lialh4 gets more bulky as H gets added and it can react with water in the air
what does spectroscopy measure
the measurement of the interactions of electromagnetic energy with matter.
what does molar coefficient e reveal
the strength with which a solution of the sample absorbs at a given wavelength
why was the reaction mix washed with sodium carbonate solution in the derivatives of carboxylic acids lab
the unreacted carboxylic acid was neutralized under mild conditions
what does infrared spectroscopy (IR) analyze
the vibrations of molecular bonds,
in the camphor reduction reaction, why should lids not be screwed back onto containers?
the waste is still generating hydrogen gas that would get trapped in the container
what is true about benzenes
they do substitution reactions, their activation energies are high bc stable, they do not lead to loss aromacicity bc h replaces bond
what is sublimation
transition directly from solid phase to gas phase
how can you drive a fischer esterification which favors equilibrium to completion
use an excess of alcohol and remove the products
what are the contents of the 2,4 DNP reagent
sulfuric acid 2,4 Dinitrophenylhydrazine ethanol
what are the health problems of excessive ultraviolet radiation
sunburn, skin cancer, premature aging of the skin, cataracts, and immunosuppression
what is broad spectrum
sunscreens that have spf 15 or greater and provide good uva protection
what is the composition of the sunscreen solution
1 g of sunscreen with warm isopropyl alcohol, diluted to 100 ml, diluted again by a factor of 100 added 50 microliter and diluted it to 5000 ul (1:100)
what are procedural steps to the derivatives of carboxylic acid lab
1.) dissolve hte benzoic in methanol in a round bottom flask 2.) add sulfuric acid 3.) pour the reaction into ice and then extract with dichlorimethane 4.) dry with magnesim sulfate 5.) remove dichloromethane by distillation 6.) distill the remaining liquid ester
procedural steps of the camphor reaction
1/) dissolve camphor in ethanol 2.) add sodium borohydride 3.) let the reaction sit for 10 minutes 4.) heat to a gentle boil 5.) pour the reaction mixture in ice water 6.) collect precipitate by filtration 7.) recrystallize
when does ketone distill
122-215
when was grignard disvoered
1901
how do esters react with grignard
2 moles (the methyl adds twice and the other O breaks off to become its own alcohol)
which molecule dissolves first in water
2-napthol (instead of salicylic acid or acetaminophen)
what are the two absorbance regions that the spectra was recorded at
310 nm and 360 nm
what is the minimum and maximum wavelength for UVA
315-400
what are the health problems of UVC (100-290)
Can be lethal, but is almost totally absorbed by ozone in the earth's atmosphere
what are the health problems of UVB (290-315)
Delayed, more intense sunburn. Skin cancer, skin aging, cataracts, immunosuppression; somewhat absorbed by earth's atmosphere (most intense at high noon)
what is the relationship between energy and wavelength
E=hc/lambda=hv
what are the health problems of UVA (315-400)
Immediate sunburn. Penetrates deeply and may lead to premature skin aging (wrinkles, age spots); may contribute to skin cancer and cataracts sunscreen spf only describes uvb and not uva most uva suncreens only offer protection against higher energy uva
what are the units for e
L/molxcm
how to do iodination reaction
add the ethanol, to solid salicylamide and dissolve, add sodium iodide, cool, and then add bleach and watch color changes until pale yellow add sodium thiosulfate and then hcl to neutralize the acid collect product by filtration and wash with water and ethanol recrystallize and and get ir
how do you do hydrolysis in the grignard reaction
add water, and then sodium bicarbonate and then saturated sodium chloride
what did we do in the borohydride reduction of camphor
added nabh4 to camphor and put it in hot water to react. We poured this into cold water to recrystallize and then purified by adding ethanol and water and dissolving and then recrystallizing. we dried this pure product and then ran a mp and ir to see if the ketone group reduced
What is reduction
adition of hydrogen to an organic molecule or the increase in the electron ownership of a carbon atom that is achieved by breaking of a bond to an electronegative atom
what happens under uv light
an electron is excited from its highest molecular orbital (HOMO) to its lowest unoccupied molecular orbital (LUMO)
what can lah and nabh4 be used with
aprotic solvent (reacts with water) but nabh4 can be used with protic solvent (in excess)
what suncreen provides the best protection against long term uva exposure
avobenzone (parsol 1789 or sunblock containing TiO2 or ZnO) . zinc and titanium provide a physical barrier to suns rays and reflect rather than absorb
whats a positive test for the iodoform test
bright yellow precipitate
what is pyrophoric and what are some examples
burst into flame upon exposure to air potassium and sodium
what are organometallic compounds
carbon to metal bond
how can you make an acid chloride
carboxylic acid and socl2
whats something that is meta directing
carboxylic acids, tetraamine with plus charge, and nitrile
which organic halide cannot be used with grignard
chloride, iodine is best
how can you use grignard to add one more carbon
co2
procedural steps of grignard reaction
dry with heat gun add 1 bromopropane to magnesium reaction must turn cloudy add ketone add ammonium chloride to quench mgx wash with sodium bicarbonate and sodium chloride dry with magnesium sulfate and distill from thf
why does 2,4 DNP work so well for this experiment
easily purified crsytals with sharp melting points
what are some of the uses of amides
enzymes, proteins, coatings (urethanes), and as solvents.
whats the only alchol to give a positive iodoform test
ethanol
what solvent do you need for grignard
ether bc oxygen on ether coordinate with the magnesium once it leaves rmr that these are explosive when highly concentrated (do not distill)
what are some of the uses of esters
fats, oils, waxes, fragrances, and solvents.
why do you use a round bottom flask in the derivatives of carboxylic acids lab
flat bottomed flaks transfer heat in an uneven fashion, and may fracture
whycanyounotuseacetonetocleanglasswareringrignardexperiment
grignard reacts with acetone
how do you do the derivatives of carboxylic acids lab
heat water to boiling and dissolve 3 g of benzoic acid in methanol and pour sulfuric acid into the flask extract with dichlorimethane wash with water and then sodium carbonate and sodium chloride and then dry the water with magnesium distill the solution and distill of sichloromethane methyl benzoate distills around 200 celcius
why is diethyl ether or THF such a great solvent for grignard
highly flammable, acts as a barrier and prevents water from entering, does not contain water (thf less flammable than water)
whats true of ether
highly flammable, flash point of 60, can form peroxides with air and sunlight, anesthetic, very low miscibility in water
why must grignard always be done in acid
protanate alcohol
how do we do the aldehydes and ketones lab
purify it by distillation test the solubility in water and get the IR do the 2,4 dnp test add the reagent to the thing dissolved in ethanol and vacuum filter this orange shit do the tollens test add silver nitrate and sodium hydroxide to the test tube and ammonium hydrozide and shake and disolve and warm gently rinse with dilute uric acid how to do the schiffs test do the iodorn test add semicarbazone
how can you turn alkynes into grignard
react with existing grignard
how does 2,4 DNP work
reacts with semicarbizide, hydrazine, phenylhydrazine or 2,4 DNP to produce solid products mmore conjugated are darker colors
how does grignard react with water
rh and mgx
what must you do in the aldehydes and ketone lab to avoid contamination
rinse with water
what is the mechansim of the schiffs test
rosaniline hydrochloride (c with three aminophenyls attached) reacts with so2 to give tetrahedral intermediate which reachts with aldehyde to add sulfate to aldehyde but produce another purple product
what is suitable for recrys solvents
should not react with the compound, should dissolve it hot, should not when cold, should dissolve the impurities at all temps or not dissolve at all
what is the tollens test
silver nitrate in aquoeus ammonia oxidizes aldehydes to carboxylic acids doesnt work with ketones bc its too mild for c-c bonds
what are the contents of the schiffs test
sodium bisulfite rosaniline hydrochloride
what is special about grignard reagents
strong nucleophiles but non toxic and dissovle in water
