CHEM 262L Final

Flashcard maker : Oscar Hall
Eye Protection
googles
Skin Protection
lab coat; neck to ankles clothing; no sleeveless; no leggings; gloves; hair tied back
Waste disposal
dispose of solvents and liquids in hazardous waste
acetic acid
corrosive; highly irritating vapors
acetic anhydride
flammable liquid and vapor, harmful if swallowed, severe skin burns and eye damage
acetone
flammable, eye irritation, drowsiness or dizziness
alumina
irritant
p-anisaldehyde (4-methoxybenzaldehyde)
irritant
o-, m-, and p-anisic acid
skin and eye irritant
aspirin (acetylsalicylic acid)
harmful if swallowed, skin irritation, eye and respiratory
camphor
flammable, irritant
o-, m-, and p- chlorobenzoic acid
ethanol
highly flammable liquid and vapor; toxic
ethyl acetate
highly flammable liquid and vapor, eye irritation
hexane
flammable, toxic; skin irritaion; damage to fertility and organs
isoborneol
irritant
magnesium sulfate
no safety concerns
4-methylacetanlide
harmful if swallowed, skin and eye irritation, respiratory irritation
2-methylcyclohexanol
flammable, toxic
2-methylcyclohexene
flammable, irritant
1-methylcyclohexene
flammable, irritant
3-methyl-4-methoxycinnamate
harmful if swallowed, skin and eye irritation, respiratory irritation
4-methyl-2-nitroacetanilide
irritant
4-metyl-3-nitroacetanilide
irritant
nitric acid
skin burns and eye damage, fire, oxidizer
phosphoric acid
sever skin burns and eye damage
potassium carbonate
serious eye irritant
salicylic acid
harmful if swallowed, eye damage
sodium bisulfite
serious eye damage; harmful if swallowed and to aquatic life
sodium hydroxide
severe skin burns and eye damage; harmful to aquatic life
sodium hypochlorite
corrosive, toxic
sulfuric acid
severe skin burns and eye damage; harmful to aquatic life
toluic acid
skin and eye irritant
trimethyl phosphonoacetate
irritant
wintergreen oil
harmful if swallowed and harmful to aquatic life
column chromatography
crystallization
used for isolation and purification of organic solids; relies on differing solubilities of organic solids in solvent; when a saturated solution of dissolved mixed organic solids is cooled, that compounds that are least soluble will crystallize first
dissolve in solvent or solvent mixture, remove insoluble by gravity filtration; isolate by vacuum filtration; cool to form crystals
distillation
process of heating a liquid until it boils, then condensing and collecting the resultant hot vapors
extraction
gravity filtration
poor into funnel over flask, fluted filter paper; used to separate liquid solid mixture when you want liquid portion of mixture
reflux
involves heating a reaction mixture to the boiling point temperature of the reaction solvent and inducing the solvent to recondense back into the reaction flask using a condenser. Refluxing a reaction mixture is a simple and efficient way to maintain a constant reaction temperature.
sublimation
direct conversion of solid to a gas; solids that readily vaporize at relatively low temperatures are good for sublimation, cooled and isolated as solid
use gentle heat
constantly change ice water to make sure cold
aspirator
inside of sidearm flask must be dry
suction filtration
buchner funnel, connect to aspirator, air sucks impurities out; when you want solid portion of mixture
thin-layer chromatography
dehydration of alcohols
nitration of an aromatic compound
oxidation of secondary alcohol to ketone
hydrolysis of ester
esterification of an alcohol
Wittig reaction
microscale reactions
reduction in time required to conduct a procedure (allows repeats or additional runs)
reduction of safety hazards
minimization of waste generation
lower cost of chemicals and glassware replacement
number of moles=
mass of material (g)/molecular weight (g/mol)
number of moles (liquid)=
[density (g/mL) x volume (mL)]/ molecular weight (g/mol)
number of moles (given Molarity and volume)=
molarity (mol/L) x volume (L)
solute mass=
molarity (mol/L) x volume (L) x molecular weight of solute (g/mol)
percent recovery
mass of pure/ mass of crude x 100%
used in purification methods
percent yield
used when a chemical reaction occurred
actual experimental yield/ theoretical yield x 100%
theoretical yield
(moles of limiting reagent) x (moles product/ moles limiting reagent) x MW product
What is the difference b/t precipitation and crystallization?
1. Crystallization occurs in a closed system, where solution is heated while adding solvent then cooled down and covered to induce the formation of crystals. Crystallization is a method of purification, while precipitation also forms a solid within a liquid, but can still contain impurities.
What problem arises if you add cold ethanol?
2. If cold ethanol was used, crystals would not have formed and impurities would not have been filtered off. During the cooling process is when crystals are formed. If impurities are more soluble, they will stay in solution while the crystals form during the cooling process.
What is the role of water in the crystallization process?
3. The role of water in this recrystallization procedure is as the crystallization solvent. Water induces the formation of crystals since the acid is not soluble in water.
What problem arises if you rinse the crystals with warm water?
4. If the crystals were rinsed with warm water, the warmth of the water can cause the compound to dissolve, leading to a reduced yield.
two uses of camphor
1. Camphor can be used as an ointment to treat pain and itching due to minor skin irritations. It can also be used against fungi that causes infection in toenails
key peaks in H1 and 13C NMR spectra
2. A key peak that would be looked for the in the 1H spectra would be the disappearance of the OH peak exhibited in the Isoborneol spectra, since it is usually extremely downfield since the oxygen shields the hydrogen. A key peak in the 13C spectra would be the different peak exhibited by the camphor, since a carbonyl peak will look different than a C-OH peak, with a shift of about 205 ppm for the former and 60 ppm for the latter
describe another type of spectroscopy that might be useful for determining success or failure of reaction
3. Infrared spectroscopy could also have been used to determine the success of the reaction. In Infrared spectroscopy, different functional groups have specific absorptions. OH groups absorb in the 3000-3500 cm-1 region, while carbonyls absorb in the 1600-1800 cm-1 region
Green Chemistry of experiment 2
4. Principle #3, Less Hazardous Chemical Syntheses makes this reaction green since bleach is used as an oxidant rather than chromium compounds, which are toxic and carcinogenic.
Principle #4, Designing Safer Chemicals, makes this reaction green since using bleach is a safer oxidant than chromium, minimizing toxicity.
Principle #10, Design for Degradation, makes this reaction green since using bleach does not produce harmful environment persistency, unlike chromium, which can leach into waterways.
Why do you remove excess water from salicylic acid?
2. Excess water was removed from the salicylic acid because water can also react with the acetic anhydride to form acetic acid. If excess water is left with the salicylic acid, more of the water will react with acetic anhydride, providing a greater yield of acetic acid rather than the desired aspirin.
two uses of wintergreen oil
3. Wintergreen oil can be used to stimulate digestion and gastric secretion if taken orally. If used topically, wintergreen oil can be used as a counterirritant, which makes sense since it is a precursor to aspirin
green chemistry of experiment 3
4. This reaction was made green by principles 5, 7, and 9. Five, safer solvents and auxiliaries, made this reaction green since water was used as solvent both during the salicylic acid and aspirin synthesis, instead of singularly using sulfuric acid. Seven, the principle of use of renewable feedstocks, made this reaction green since wintergreen oil was used to synthesize salicylic acid from benzene instead of using non-renewable crude oil extracts to extract benzene. Nine, the principle of catalysis, made this reaction green since sulfuric acid and phosphoric acid were used in this reaction to help speed it up and ensure the complete incorparotion of all synthetic materials into the final product.
justify stereoisomer formed using NMR
1. Based on analyzing a proton NMR spectrum, the stereoisomer synthesized was the E stereoisomer. The proton drawn in the chemical formula would have the signal most downfield, 7.65, since it is most deshielded by the aromatic ring and the double bond. The aromatic ring protons would have the signals of 7.47 and 6.90. The same coupling constant of 15.9 Hz indicates the alkene protons the 7.65 and 6.31 ppm. The value of 15.9 Hz indicates that this is the E stereoisomer, since the cis isomer would only produce a signal of ten. The protons on the aromatic ring have a splitting signal since they have different environments, either the CH3O group or the double bond and carbonyl.
why is phosphonate so acidic
2. Phosphonate is so acidic because of the direct oxygen hydrogen bond that is being broken, transferring the electron density of the phosphorous ion, which can handle more than eight electrons around it. RESONANCE
What properties make methyl 4-methoxycinnamte a sunscreen analog?
3. Methyl 4-methoxycinnamte is an effective sunscreen because of its high molar absorptivity value, it can also absorb UVB rays by only using small concentration of the sunscreen.
however, lambda max is small
green chemistry of experiment 4
4. This reaction was made green by principles 5, 1 and 9. Five, safer solvents and auxiliaries, made this reaction green since by preparing a phosphonate ylide, the phosphorous byproduct is a phosphate ester and soluble in water. One, prevention, made this reaction green, since by using the Horner-Wadsworth-Emmons modification, only one stereoisomer is formed which prevents the waste of an excess stereoisomer. Nine, catalysis, made this reaction green, since potassium carbonate was used as a catalytic reagent to reduce the waste of another stoichiometric reagent.
major product of nitration
1. The major product obtained was 4-methyl-2-nitroacetanilide, as evidenced by both the crude melting point range (71.3-73.7̊C) and the pure melting point range (79.0-83.0̊C), which are both closer to the literature value of 4-methyl-2-nitroacetanilide, 93̊ C. The other possible product for this reaction was 4-methyl-3-nitroacetanlide has a literature value melting point range of 143-145̊ C, which is much higher than the experimental values obtained. This also holds consistent with the expected product of a nitration of 4-methylacetanilide. In nitration of benzene, -NHCOCH3 is a moderately activating group, while -CH3 is only a weakly activating group. When a benzene ring has two competing substituents, the one with greater activating ability will govern the placement of the added substituent. -NHCOCH3 is an ortho-para directing group, and since the para position at 4 is already occupied by the -CH3, the new substituent, -NO2 will be directed to the ortho position at carbon 2, which is consistent with the experimental data of the major product obtained of 4-methyl-2-nitoracetanilide.
The expected major product of the nitration of 2-methylacetanilide is 2-methyl-4-nitroacetanilide. Similar to the nitration of 4-methylacetanilide, -NHCOCH3 will act as an ortho-para directing group since it is a moderately activating group over the weakly activating -CH3 group. However, in this case, the -NO2 group will be directed to the para position, since the -CH3 group in the 2 position causes steric hindrance around the second ortho position.
purity of sample
2. a. Based on the data given, the sample does not appear to be pure. The melting point range of 115-125̊ C is a broad range, while pure compounds are indicated by narrow ranges. The one spot on the TLC indicates purity, since only one compound The small Rf value indicates that the compound did not travel far compared to the solvent, indicating that separation proceeded ineffectively. This could have been due to using the wrong solvent for the compound. For example, the 10:1 hexanes: ethyl acetate solution could have had too low of an ethyl acetate concentration for the selected sample, leading to the ineffective separation.
b. If a sample of the pure compound is available, the melting point range could be obtained for the pure compound and compared to the experimental range to see if the pure compound also had a wide range and to see if the experimental is close to the purified range. Another TLC analysis could take place to see if a different Rf value will be obtained using a better solvent, for example the 1:1 hexane ethyl acetate solvent used in the previous experiment.
what fractions contained desired compound
The fractions that contained the desired compound were indicated by the displaying only one TLC spot, since the purified product was desired. Fractions 1-5 displayed this spot, while fractions 6 and 7 had a second spot, indicating impurities. The movement of the spots also was similar to the movement of the crude product in Part 1.
falls below gel
f the solvent level falls below the top of the gel, air pockets and cracks can develop in the gel, leading to uneven elution.
starting material position on column
The starting material would appear higher on the column relative to the product because it is more polar, therefore having a higher affinity for the solvent. This is evident because of the smaller Rf value obtained relative to the product during TLC analysis,

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