ochem 2 lab final
maleic anhydride + anthracene
"endo" diels-alder adduct
aldol reaction
-2 of C6H5CHO and 1 C5H8O -heat up with magnetic stirring bar
esters, synthesis of aspirin
-acetylsalicyclic acid (aspirin) -dont exceed temp (70-80C) in hot water bath twice.
anthracene
-aromatic hydrocarbon -diene when reacting maleic anhydride
dilantin step 1
-benzaldehyde to benzoin -just mix together and leave a week -NaOH to react with HCl and release thiamine
dilantin step 3
-benzil to dilantin -reflux
dilantin step 2
-benzoin to benzyl -reflux
polystyrene production
-heat in fume hood over metal block
polyurethane production
-just mix together -foam
nylon production
-mix together then grab out solid
which bromine in 1,2-dibromo-4-nitrobenzene would be substituted by a nucleophile
1-bromo would be substituted because it is in the para position and due to the movement of electrons it is the easiest way instead of the meta position
how to calculate the theoretical yield
1. take limiting reactant and both will be mol of limiting 2. add MW of both reactants together 3. multiply together to get grams
following progress of reaction by TLC in esterification
3 lanes would be spotted with different mixtures to help analyze the reaction. after some time you can observe under UV light how well the reaction worked by comparing it to others
phenol with Br reacts with aniline, EtOH/H2O
Br replaced by aniline attached at NH
phenol with Br reacts with CH3CH2NH2, EtOH/H2O
Br replaced with Nh2CH2CH3 at NH
phenol with Br reacts with KSCN, EtOH/H2O
Br replaced with SCN
how do you account for smell of vinegar when an old bottle of aspirin is opened
H2O enters eveytime you open bottle which begins hydrolysis reaction which creates acetic acid which smells like vinegar
source of acid that catalyzes esterification
H2SO4
HCl is as strong a mineral acid as H2SO4. why would it not be satisfactory catalyst for this reaction
H2SO4 is also a dehydrating agent, therefore, forces equilibrium to right and produces more products
purpose of washing ether solution of product with 5% NaHCO3 solution in esterification
NaHCO3 will remove the unreactive benzoic acid and help make the compound pure
chemical equation showing formation of aspirin from salicyclic acid and acetic anhydride
SA-Nu AA-E
saponification
The hydrolysis of an ester in the presence of a base. -irreversible
what is a meisenheimer complex
a 1:1 reaction between an arene carrying an electron withdrawing group and a nucleophile
esters made by
alcohols or phenols with organic or inorganic acids
what organic functional group do nylon and proteins have in common
amide
what does it mean to say that aspirin is an analgesic and an antipyretic
analgesic reduces pain and antipyretic lowers body temp. aspirin does both
rxn between urea and isocyanic acid strongly favors urea, why does it still go to completion?
because urea replenishes the isocyanic acid consumed
Cu2+ blue and Cu+ yellow, how do you account for color changes observed during oxidation of benzoin to benzil
copper used for oxidation starts out as Cu2+ and converted to Cu+ by NH4NO3
maleic anhydride
dienophile -limiting reactant based on MW into mmol
nucleophilic aromatic substitution
done in microwave -1980 -yellow to light yellow
common large scale use of both urea and ammonium nitrate
fertilizer
what causes solution to foam and expand in volume during polyurethane production
formation of gas
reflux
heating the chemical reaction for a specific amount of time, while continually cooling the vapour produced back into liquid form, using a condenser. -diels-alder reaction uses
advantage of generating a reagent in situ
in situ allows slow release of reagent and can control rate of reaction
2 things you could do to improve yield of esterification
increase conc of alcohol or CA to shift equilibrium to the right
why is 2,5-dibenzalcyclopentanone yellow?
it is highly conjugated, therefore energy state is in the range where molecule can absorb visible color and leaves yellow for us to see
would methanol or hexane be a better solvent when using microwaves to heat a reaction mixture
methanol is polar which works well with microwaves, therefore, the substance would heat quicker and better. Hexane is nonpolar and doesnt heat well
purpose of Na2CO3 in synthesis of nylon
neutralizes HCl allowing further bonding to take place
what types of reactants are needed for successful crossed aldo reaction
one molecule needs to be able to form an enolate ion and the other should be able to form alpha bonds and have no alpha hydrogens
synthesis of dulcin
p-phenetidine (p-ethoxyaniline) with isocyanic acid (by urea) -reflux
closer melting point is to theoretical melting point
purer the product
methyl benzoate by fischer esterification
reflux
hydrolysis of esters
reversed reaction of making esters -ester reacts with water
dulcin is artificial sweetener but can be toxic in large amounts because
starts converting to p-aminophenol in the body
why styrene soluble in toluene but not ethanol
styrene and toluene both non-polar. ethanol is polar
why do you need to grease joint between condensor and flask in dilantin synthesis
they become stuck after reflux and hard to separate
explain why the two sets of nitrogen protons in the H NMR spectrum of dulcin have such different chemical shifts
theyre connected to different atoms. one is amide and other is connected to two C's. gives a difference in shielding factors.
why is cold solvent used to wash product rather than room temp or hot solvent in Nu subs rxn
to prevent the exothermic or endothermic reaction from happening with 2 or more reactants
following progress of reaction by IR spectroscopy in esterification
use pure reactant and reactant mixture then obtain graphs and analyze
why is water detrimental to acid catalyzed esterification
water reacts with product of ester to hydrolyze it back to acid and alcohol. ensures reversibility
why does the initial yellow color of the reaction fade during the diels-alder reaction?
when the substance is heated, conjugated bonds are broken up which causes the color to fade