CHEM 262L Final – Flashcards

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lab coat; neck to ankles clothing; no sleeveless; no leggings; gloves; hair tied back

dispose of solvents and liquids in hazardous waste

corrosive; highly irritating vapors

flammable liquid and vapor, harmful if swallowed, severe skin burns and eye damage

flammable, eye irritation, drowsiness or dizziness

irritant

irritant

skin and eye irritant

harmful if swallowed, skin irritation, eye and respiratory

flammable, irritant

highly flammable liquid and vapor; toxic

highly flammable liquid and vapor, eye irritation

flammable, toxic; skin irritaion; damage to fertility and organs

irritant

no safety concerns

harmful if swallowed, skin and eye irritation, respiratory irritation

flammable, toxic

flammable, irritant

flammable, irritant

harmful if swallowed, skin and eye irritation, respiratory irritation

irritant

irritant

skin burns and eye damage, fire, oxidizer

sever skin burns and eye damage

serious eye irritant

harmful if swallowed, eye damage

serious eye damage; harmful if swallowed and to aquatic life

severe skin burns and eye damage; harmful to aquatic life

corrosive, toxic

severe skin burns and eye damage; harmful to aquatic life

skin and eye irritant

irritant

harmful if swallowed and harmful to aquatic life

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

process of heating a liquid until it boils, then condensing and collecting the resultant hot vapors

poor into funnel over flask, fluted filter paper; used to separate liquid solid mixture when you want liquid portion of mixture

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.

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

buchner funnel, connect to aspirator, air sucks impurities out; when you want solid portion of mixture

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

mass of material (g)/molecular weight (g/mol)

[density (g/mL) x volume (mL)]/ molecular weight (g/mol)

molarity (mol/L) x volume (L)

molarity (mol/L) x volume (L) x molecular weight of solute (g/mol)

mass of pure/ mass of crude x 100% used in purification methods

used when a chemical reaction occurred actual experimental yield/ theoretical yield x 100%

(moles of limiting reagent) x (moles product/ moles limiting reagent) x MW product

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.

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.

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.

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.

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

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

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

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.

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.

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

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.

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.

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

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

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.

1. The major product obtained was 4-methyl-2-nitroacetanilide, as evidenced by both the crude melting point range (71.3-73.7?C) and the pure melting point range (79.0-83.0?C), which are both closer to the literature value of 4-methyl-2-nitroacetanilide, 93? C. The other possible product for this reaction was 4-methyl-3-nitroacetanlide has a literature value melting point range of 143-145? 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.

2. a. Based on the data given, the sample does not appear to be pure. The melting point range of 115-125? 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.

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.

f the solvent level falls below the top of the gel, air pockets and cracks can develop in the gel, leading to uneven elution.

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,