acid/base or chemical extraction
what reagent is added to the test tubes to produce the solid?
HCl
what is the drying agent for this lab?
MgSO₄
what reagent reacts with benzoic acid?
NaHCO₃
what reagent reacts with 2-napthol?
NaOH
what is the pKa of 2-naphthol?
-10
what is the IR peak for C=O bonds?
-1700 cm⁻1
what is the IR peak for C-H bonds?
-3000 cm⁻1
what is the IR peak for O-H bonds?
-3300 to 3600 cm⁻1
what is the pKa of benzoic acid?
-4.1
other common drying agents?
-CaCl₂ -CaSO₄ -MgSO₄ -K₂CO₃ -Na₂SO₄
what should be added to test tubes B and C to form benzoic acid and 2-naphthol?
-HCl
emulsion
-a drop or suspension of liquid in another -they are very stable once they are formed -countered by stirring/mixing well and vacuum filtration/centrifugation
what do drying agents do?
-absorb or remove water
what is an example of liquid drying agent?
-aqueous NaCl pull water into the aqueous layer
what is backwashing?
-backwash with ether to remove and organic components from the test tubes
what is the conjugate base of benzoic acid?
-benzoate -same structure but with hydrogen proton removed
what is in the ternary mixture?
-benzoic acid -2-napthol -1,4-dimethoxybenzene
intermolecular forces for 2-naphthol?
-can hydrogen bond in water -polar
intermolecular forces for benzoic acid?
-can hydrogen bond to water -polar
what are the three functional group from this experiment?
-carboxyl group -phenol -ether
the aqueous layer
-contains the organic impurities
what is the ternary mixture dissolved in?
-diethyl ether -test tube A
inter molecular forces for 1,4-dimethoxybenzene?
-dipole dipole attractions -polar
why do you have to vent the separatory funnel?
-gas is produced during the reaction which will cause a pressure buildup
what kind of filtration is used for test tube A, 1,4-dimeothoxybenzene?
-gravity filtration
extraction
-isolation technique based on the solubility of various components in solvent(s)
what are the three types of extraction?
-liquid/solid: for example, the extraction of a flavor and odor from dried veggies (tea) -liquid/liquid: where the two liquids react, the reaction goes to completion, and creates to distinct layers -acid/base: performing a series of acid/base reactions to yield a strong acid, weak acid, and a neutral compound (can also be done to produce bases)
magnesium sulfate
-molar mass: 120.36 g/mol
benzoic acid
-molar mass: 122.12 g/mol -melting point: 122.4 C
1,4 dimethoxybenzene
-molar mass: 136.16 g/mol -melting point: 54-56 C
2-naphthol
-molar mass: 144.17 g/mol -melting point: 122 C
hydrochloric acid
-molar mass: 36.46 g/mol
sodium hydroxide
-molar mass: 39.99 g/mol
sodium bicarbonate
-molar mass: 84.00 g/mol
what is the conjugate base of 2-naphthol?
-naphthalen-2-olate -same structure with hydrogen proton removed and negative charge on oxygen
ionizable proton?
-on 2-naphthol and benzoic acid -meaning there is a proton that can be ionized -their conjugate bases have a negative charge on the oxygen, meaning they will be more soluble in water
properties of a good extraction solvent?
-same properties as a recrystallization solvent -should consider its solubility in relation to other components -should consider its reactivity in relation to other elements -should easily dissolve compound to be extracted -low boiling point -should NOT react w/solute or other solvents -inexpensive -NOT flammable or toxic -NOT miscible in water -need to know the solubility to know which layer comes out on top
what goes in test tube C after sodium hydroxide is added?
-the aqueous layer is removed and put into test tube -test tube C contains naphthalen-2-olate
what goes on test tube B after sodium bicarbonate is added?
-the aqueous layer is removed and put into test tube B -test tube b contains the sodium benzoate
what remains in test tube A after sodium bucarnonate and sodium hydroxide were aded and the aqueous layers removed?
-the neutral, organic layer -test tube A contains 1,4-dimethoxybenzene
what are the two layers produced in liquid/liquid extraction?
-the organic/ether layer and the aqueous layer
the organic/ether layer
-this layer contain the organic component, will not be soluble in water and will separate itself from the aqueous layer, it is less dense and will rise to the top
what type of filtration is used for test tubes B and C, benzoic acid and 2-naphthol?
-vacuum filtration
diethyl ether
-very strong odor -very flammable -hard to extract
diethyl ether
molar mass: 74.12 g/mol