Cheat Sheet Organic Chemistry Laboratory

Exp. 1 Fisher Esterification RCO2H+ROH=RCO2R+H2O Exp.2 Nitration of Methyl Benzoate Esters, derived from replacement of -OH group with an alkoxy -OR group. Fabrics plastic bottles and insulators. Inability to function as a hydrogen donor, prevents associating with other ester molecules - >-1 more volatile than carboxylic acids of similar molecular weight. IR band @ 1730-1750cm . Carboxylate acid+alcohol. Replaced -OH no H-bond donor. Reversible Le Chatelier’s, under basic conditions Saponification. Procedure: off nucleotide, add H2SO4 (catalyze), reflex, cool and add H2O, rinse w/ether, drain H2O, wash w/bicarbonate, wash w/saturated NaCl, decant dry. Caution: methanol is flammable and toxic. Conc H2SO4 -> is corrosive. Vent the separatory funnel frequently after swirling and subsequent shaking since CO2, gas is evolved and will build up pressure in the funnel. If attempting to distill high BP esters, don’t circulate H2O in the condenser as it may crack from thermal stress. *Reflux involves the condensation of vapors. The reagents /solvents which boil under high temperatures will return to the flask, allowing us to speed up a reaction using higher temperatures while maintaining a constant volume. Solvent extraction2 is a separation method using a separatory funnel. The product (methyl benzoate) is soluble in ether whereas the methanol and sulfuric acid will dissolve in the water layer. Separate into layers based on their density. Exp.3 Friedel Crafts Acylation of Ferrocene Requires aluminum chloride, ferrocene needs weaker catalyst phosphoric acid, highly colored TLC analysis, stationary phase, mobile phase Rf = Procedure: ferrocene + acetic anhydride +H3PO4. Warn gently, reflux. · Over ice rinse. Stir neutralize (NaOH, Biocarbon). Filter, TLC-recrystallized TLC. Acylation: adding an acyl group (R-C=O) to a compound. Acyl halides, used as acylating agents (for strong electrophiles) when treated with a metal catalyst. Electrophilic aromatic SUB. Acyl halides, acid chlorides and acid anhydrides also used as acylating agents Lewis ACIDs are acids and aluminum trichloride. FOOD stock, fine chemicals, and synthetic intermediates. Ferrocene (Fe(C5H5)2) “Super aromatic compound ORANGE solid, soluble in most organic solvents. 2 cyclopentadienyl rings w/ central iron atom. Very stable, unaffected by strong bases water air and can heat to 400C. Created Organometallic chemistry. Not large-scale applications, lots of niches. CATALYST: AlCl3 or H3PO4 (milder conditions). Addition of deactivation group, -> if you add another it will happen on other ring ONE MONOACETYL derivative and ONE DIACETYL derivative. Acetylferrocene and ferrocene both HIGHLY colored= separate easy TLC. THIN LAYER CHROMOTOGRAPHY: used to separate nonvolatile mixtures: Done on INERT substance (plastic or glass), Coated with ABSORBANT layer (silica gel/ aluminum oxide)STATIONARY PHASE, Solvent= MOBILE PHASE to draw up plate via CAPILLARY ACTION. Separations dependent: Absorption and separation. Compounds with HIGH attraction to absorbent = slow, LESS attraction to absorbent = move FAST. CAUTION: Set origin above solvent, Close chamber to make sure TLC runs smooth, Don’t let solvent front run off edge of TLC plate, Don’t look into UV lamp. Mixed acid (H2SO4+HNO3), introduces nitro group (-NO2), produces nitronium (NO2 ), H2SO4 not consumed, electrophilic aromatic substitution (H2SO4 catalyzed), attach by electron rich ring (nucleophile), nitronium electron poor electrophile. Selective: deactivating groups have e withdrawing electrons. Slow the reaction, meta director. Procedure: H2SO4 + methyl benzoate. Cool, nitration mix. Warm + ice. Filter, wash, recrystallize. Why use an ice bath? To prevent the NO2 ion from destabilizing and avoid the formation of side products. Nitration= chemical process to introduce (-NO2). Rare in nature, used in explosives (TNT). Synthesis= “mixed acid” of conc. Nitric and sulfuric acid mixture produces nitronium ion(active species) H2SO4 not consumed= catalyst, and absorbent for water. Electrophilic aromatic sub.= aromatic ring attacks. Sulfuric acid in present experiment = solvent, and cat, to make nitronium ion. Caution: use ice bath and add slow since its exothermic. carosive Exp.4 Thiamine Catalyzed Benzoin Condensation Caution: control ph and temp of solution, NaOH corrosive. Addition reaction including 2 aldehydes, benzaldehyde to benzoin, catalyzed by nucleophiles, classic is cyanide, non-reversible. Procedure: Thiamine HCl-safer, heat sensitive, thiamine to H2O, ethanol, cool, NaOH, ph 10-11. chill, benzaldehyde reflux. Cool, crystalize filter recrystallize. Benzoin condensation: (+) reaction of (2) aldehydes usually between (2) aromatic aldehydes, makes acyloin. Benzaldehyde \-> benzoin. CAT= CN (nucleophile) Or THIAMINE hydrochloride (vitamins B). MECH. Cyanide anion, (NaCN). *Reacts with the aldehyde in a nucleophilic addition l. Rearrangement of the intermediate2 allows addition of the second carbonyl group in a second nucleophilic addition3. Proton transfer4 and elimination of the cyanides affords benzoin as the product. REVERSABLE, distribution of products depends on relative thermodynamic stability of the reagents and product. Exp.5 Dibenzaldehyde by Aldol Condensation Aldol reaction + dehydration, base or acid catalyzed, solvent dissolves reactant + intermediate (benzol acetone). Aldol Condenation: enol/enolate ion reacts with carbonyl compound to make a B- Hydroxyaldehyde (Aldol[ALDehyde and alcoh-OL]) or B-hydroxy ketone followed bydehydration to form a conjugated enole. 1st part is aldol reaction. 2nd part is dehydration (eliminate or remove water/alcohol) CAT: Can use acid or base(NaOH). Aldol condensation can be carried out via kinetic or thermodynamic control. Caution: use correct amount for each step. Time strict, or will make benzalacetone. Experiment: CAT: base NAOH; Solvent Ethanol; Aldehyde and Ketone with NaOH base CAT,= MIXED ALDOL condensation Clauses-Schmidt reaction(AKA); Dibenzalacetone is made by condensation or acetone with (2) equivalent benzaldehyde’s; Aldehyde carbonyl is more reactive than ketone carbonyl and reacts with anion of ketone -> makes hydroxyketone via base cat Dehydration. Benzaldehyde-> benzalacetone+ benzaldehyde-> Dibenzalacetone. WASHING with water to react with all NaOH. -M chich = = -E P2N B C D Classification tests: Alcohols 1. Jones oxidation 2. Cerium (IV) nitrate 1. unk+acetone+jones reagent 2. unk+H2O or Dioxane+cerium nitrate reagent * 1. green color appears within 5sec -> 1 or 2 * 1. Aldehydes also give a positive test w/Jones reagent. * alcohol. No reaction -> 3 alcohol. 2. color changes from yellow to red. Aldehydes 1. 2,4-dinitrophenylhydrazones 2. bisulfite 3. tollens 1. unk+ethanol+2.4-DNPH reagent 2. unk+methanol+NaHSO3 25% 3. AgNO3+NaOH+ammonia+unk 1. Formation of yellow, orange or red precipitation. 2. precipitate forms within 10min. 3. silver mirror or ppt of silver is formed on the side of the test within 2min. Amines Hinsberg Unk+benzenesulfonyl chloride+methanol+NaOH+HCl 1.Precipitate after addition of 6M HCl -> 1* or Use a boiling H2O bath to het the content tube of unk amine & 2* amine. benzenesulfonyl chloride for 2min before adding 6M NaOH. 2. no precipitate->3* amine 3. after addition of 1.5M NaOH, heat & shake for 2min, ifprecipitation dissolves->1* amine not dissolve->2* amine. Anhydrites & acid Acidic iron (III) hydroxamate halides Unk+hydroxylamine HCl+HCl+iron (III) chloride Red-blue color appears Use hydroxamine HCl prep in ethanol. Ketones 1. 2,4-DNPH 2. bisulfite 3. iodoform 1.unk+ethanol+2,4-DNPH 2. unk+methanol+NaHSO3 3. unk+HCl+I2 in KI+dichloromethane+methanol-H2O mixture 1. formation of a yellow, orange or red precipitation. 2. precipitate forms within 10min. 3. the brown color of the reagent disappears&yellow iodoform separates. This ppt when dried has MP 119*C. 1. yellow derivatives are formed from isolated carbonyl groups. Orange-red derivatives are formed from aldehydes, unhindered cyclic&methyl ketones give a pos test. 2. A pos test is given by substances such as CH3COR, CH3CHOHR, CH3CH2OH, CH3CHO, RCOCH2COR Esters Alkaline iron (III) hydroxamate Unk+hydroxylamine Red-blue color appears HCl+NaOH+HCl+ethanol+Iron (III) chloride Us ehydroxylamine HCl prep in ethanol Polyhydric alcohols Periodic acid Periodic acid+HNO3+unk+AgNO3 Instantly appearance of a white precipitation + test given by alpha hydroxy aldehydes, alpha hydroxy ketones, alpha hydroxy acids Amides 1.hydroxamic acid 2. unsubstituted amides 3. substituted amides 4. anilides 1. unk+ethanol+hydroxylamine HCl 2. NaOH+unk+CuSO4 3. unk+NaOH+ethyl ether+HCl 4. unk+H2SO4+K2Cr2O7 1. Red-blue color 2. blue color on filter paper 4. blue-pink color 1. + test for all nitriles&amides except benzanilide. 4. test is + for an anilide that doesn’t have substituents on the ring. Phenols 1. Iron (III) chloride 2. sensitive test 1. unk+H2O-alcohol mixture+iron(III) chloride 2. unk+chloroform+iron (III) chloride+pyridine Iron(III) chloride+KSCN+unk+toluene Ethers & diaryl ethers Unsaturated hydrocarbons Alkyl & aryl halides Aromatic hydrocarbons 1. yellow derivatives are formed from isolated carbonyl groups. orange-red derivatives are formed from aldehydes or ketones conj w/double bonds or aromatic rings. 2. shake the mixturewell for 10min. aldehydes, unhindered cyclic&methyl ketones give a + test. For liquid or solid sample that is very sparingly soluble in H2O, add=5 drops of methanol before addition of bisulfite solution. 3. the test is used to distinguish aldehydes from ketones. 1. Appearance of either red, blue, green, purple 1. use iron(III) chloride prep in H2O color 2. use iron (III) chloride prep in chloroform 2. if phenols or enols are present-> produce a color (blue violet) Ferrox Appearance of a red-purple color Diphenyl ether doesn’t five a + test. Alkyl ethers are soluble in HCl, alkyl aryl & diaryl ethers are insol in HCl&H2SO4. 1.bromine in carbon tettrachloride 1.unk+carbon tetrachloride+bromine in carbo 1. bromine solution added dropwise -> 2. potassium permanganate tet+hydrochloric acid. decolorizes 2. unk+acetone+potassium permanganate 2. color change form purple to brown MnO2 Alcoholic silver nitrate Unk+ethanol+silver nitrate saturated Precipitation -> alkyl bromine, iodine, allyl halides. No recipitation then heat to boiling. Friedel-crafts Aluminum chloride Orange or red color -> benzene& its White smoke inside the test tube anhydrous+unk+chloroform derivatives. Blue or purple -> naphthalene. Purple color -> biphenyl or phenanthrene. Green -> anthracene Derivatives: Acids Alcohols& phenols Aldehydes& ketones Primary& secondary amines Tertiary amines 1. anilides 2. amides 1. 3,5-diitrobenzoates 2. phenylurethanes 1. semicarbazones 2. 2,4-DNPH 1. benzamides 2. acetamides methiodides 1. unk+thionyl chloride+aniline+toluene+HCl+NaOH+CaCl anhy.+ethanol 2. unk+thionyl chloride+ammonia conc+ethanol 1. 3,5-dinitrobenzoyl chloride+unk+Na2CO3+ethanol 2. unk+phenyl isocyanate+pyridine+ligroin 1. unk aldehyde/ketone+semicarbazide HCl+methanol+pyridine 2. unk aldehyde/ketone+2,4-DPH prep in H3PO4+ethanol+HCl conc 1.unk+NaOH+benzoyl hydrozide+HCl+ethanol 2. unl amine+acetic anhydride+HCl+ethanol+pyridine+H2SO4 Unk amine+methyl iodide+ethanol+ethyl acetate Aromatics nitration H2SO4 conc+unk aromatic+HNO3 conc+methanol Aryl halides 1. nitration 2. sisechain oxidation products hydrolyze 1. H2SO4+unk aryl halide+HNO3 conc+methanol 2. Na2Cr2O7+H2SO4 conc+unk aryl halide+ammonia conc+methanol H2O mixture 1. acids 2. amides 3. anilides 1. unk anhyd+Na2CO3+ethyl ether+H2SO4 2. ank anhyd+ammonia conc+ethanol 3. unk anhyd+aniline+toluene+HCl+NaOH+ethanol Esters& amides Anhydrides& acid chlorides Ank amide+NaOH+ethyl ether+HCl conc+Na2SO4 anhydr 1. u must make a solution of aniline in toluene before adding it to the reaction mixture 2. phenyl isocyanate or alpha naphthalurethane 0 = c - - OH Y Benzoa + H2SOy CHz0H & 10-CH3 , 4 methyl benzoate Q- OCH3 · xc- OCH3 ↳ None -ch I = chi =