Analysis of Oxygen Bearing Organic Compounds

Analysis of Oxygen Bearing Organic CompoundsBirung, De Leon, Gatdula, Joquico, Mallari KeywordsAlcoholAldehydeKetoneEsterCarboxylic AcidDichromate TestTollens TestLucas TestDNPH TestHydroaxamic Acid TestIodoform TestObjectivesDifferentiate the various types of oxygen-bearing organic compoundDevice a scheme to distinguish each functional groupCharacterize an unknown sample through parallel chemical testsFunctional GroupsAlcoholsn- Propanol2- PropanolButanolKetonesAcetoneAldehydesFormaldehydeEstersEthyl AcetateIntroductionn- Propanol primary alcoholCH3CH2CH2OH colorless liquidMolar mass: 60.09 g/molPolar solventcleaning fluid, adhesive and stain remover, preservative

2- PropanolIsopropyl AlcoholC3H8O or C3H7OH / CH3CHOHCH3colorless, flammable chemical compound with a strong odor secondary alcoholBoiling point: 82.6 CMolar mass: 60.1 g/mol

2-Butanol secondary alcohol CH3CH(OH)CH2CH3flammable, colorless liquidPolar Solvent Molar mass: 74.122 g/molBoiling point: 98 to 100 C

FormalinFormaldehyde CH2Ogas at room temperature colorless and has a characteristic pungent, irritating odornail hardeners and/or nail varnishBoiling point: -19 CMolar mass: 30.031 g/mol

Acetonepropan-2-one(CH3)2COcolorless, volatile, flammable liquidsimplestketonePolar Solventactive ingredient in nail polish remover and as paint thinner.Boiling point: 56CMolar mass: 58.08 gmol1

Ethyl Acetate C4H8O2colorless liquid, characteristic sweet smellglues, nail polish removers, decaffeinating tea and coffee, and cigarettes ester of ethanol and acetic acidPolar solvent

Chemical Tests Used in the ExperimentDichromate TestUsed to distinguish between primary, secondary, and a tertiary alcohol.Primary alcohol- oxidized to adehydes and then further oxidized to carboxyllic acidSencondary alcohol-oxidized to ketonesTertiary alcohol- not oxidized

R-CH2(OH)R-CO-OHR-CH(OH)-R R-CO-R

Tollens TestAlso called silver-mirror testUses Tollens reagent which contains silver ions coordinated to ammonia [Ag(NH3)2OH]Used to distinguish between an aldehyde and a ketoneTollens reagent oxidizes aldehydes to ammonium salts of carboxyllic acid

R-CHO R-COO-NH4+

This reaction is accompanied by the reduction of silver ions which in turn forms the silver mirror coat observed in the test tube.

Lucas TestUses Lucas reagent which is an aqueous solution of a strong acid (HCL) and zinc chloride.A substitution reaction where the chloride of the zinc chloride is replaced by the hydroxyl group of the alcohol takes placeUsed to classify alcohols in accordance with their reactivityPrimary- no visible reactionSecondary- solution turns turbid in 5-20 minutes with heatingTertiary- solution turns turbid rapidly and forms two layersThe formation of turbid solutions happens because of the formation of a chloroalkane

R-OH R-Cl

The reaction only happens when the alcohols used are soluble in the Lucas reagentDNPH TestDNPH stands for dinitrophenylhydrazineUsed to qualitatively detect the carbonyl group functionality in aldehydes and ketonesPositive result is a yellow or red precipitate known as the dinitroprhenylhydrazoneIt is a condensation reaction where two molecules join and lose water

R-CO-R R-C-RIodoform TestUsed to identify methyl ketonesNAOCl oxidizes a methylcarbonyl groupWhen iodoform is liberated from the mixture, it forms a yellow precipitate which indicaes that a reaction has occuredOnly ethanal aldehyde and methyl ketones can undergo this reaction

R-CO-CH3R-COO- + CH3IHydroxamic Acid TestTest for esters, whereby the ester is converted to a hydroxamic acid A positive result is a red-purple solutionIf the prior tests do not identify a sample as an aldehyde or ketone, then the sample could be an ester.

MethodologyBirung, Adriel T.Chemical TestsReaction 1: Dichromate TestReaction 2: Tollens TestReaction 3: Lucas TestReaction 4: DNPH TestReaction 5: Iodoform TestReaction 6: Hydroaxamic TestBirung, Adriel T.Dichromate TestDichromate oxidizes primary/secondary alcohols and aldehydes to ketones or carboxylic acids.

R-CH2 (OH) R-CO-OH

R-CH(OH)-R R-CO-R

Green solution Tollens TestTollens reagent [Ag(NH3 )2 OH] oxidizes aldehydes to ammonium salts of carboxylic acids

R-CHO R-COO- NH4+

Silver mirror coatLucas Test Alcohols are converted to alkyl chlorides with ZnCl2

R-OHR-Cl

Turns turbid fastDNPH Test DNPH reagent condenses with carbonyl containing molecules

R-CO-RR-C-R

Red-orange pptIodoform Test NaOCl oxidizes a methylocarbonyl group and in the process yield a yellow ppt of iodoform

R-CO-CH3 R-COO- + CH3

Yellow ppt

Hydroaxamic Test Hydrogen peroxide reacts with aromatic primary amides to form the hydroxamic acid, which then reacts with ferric chloride to form ferric hydroxamate complex having a purple color Purple ppt

Unknown SampleDichromate RxnGreen sol?Non-OxidizableOxidizableNoYesTollens RxnMirror coat?NoYesAldehydes1o or 2o AlcoholDNPH RxnRed orange ppt?YesNo3o AlcoholsKetonesLucas Rxn.Turbid fast?YesNo1o Alcohols2o AlcoholsRESULTSGroup 1 & 2Dichromate TestTollens TestLucas TestDNPH TestIodoform Test Hydroxamis Acid Testn-PropanolBlue green solutionColorless solutionColorless solutionOrange solutionColorless solution with white precipitateReally light yellow solution2-PropanolBlue green solutionColorless solutionColorless solutionOrange solutionColorless solution with white precipitateColorless solution3-ButanolOrange solutionColorless solutionCloudyYellow precipitate in orange solutionRed bubbles in UL rusting yellow solutionColorless solutionFormalinBlue green solutionGrey precipitate (mirror) solutionColorless solutionYellow precipitate in orange solutionColorless solutionColorless solutionAcetoneOrange solutionColorless solutionColorless solutionYellow precipitate in orange solutionColorless solutionColorless solutionEthyl AcetateUL- Light orangeLL- orangeColorless solutionColorless solutionOrange solutionUL-reddish blackLL- Golden-like with white precipitateColorless solutionGroups 3 & 4Dichromate TestTollens TestLucas TestDNPH TestIodoform TestHydroxamic Acid Testn-PropanolBlue solutionColorless solutionColorless solutionOrange solutionWhite precipitate in light yellow solutionLight brownish yelllow solution2-PropanolBlue solutionOil-like substance in colorless solutionColorless solutionOrange solutionYellow precipitate in colorless solutionYellow solution3-ButanolBrownish orange solutionColorless solutionLight yellow solutionOrange precipitate in yellow solutionBlack precipitate in brown solutionBright yellow solutionFormalinBlue-green solutionSilver precipitate in colorless solutionColorless solutionYellow precipitate in yellow solutionWhite precipitate in colorless solutionYellow solutionAcetoneOrange solutionColorless solutionColorless solutionOrange precipitate in yellow solutionYellow precipitate in colorless solutionOrange precipitate in orange solutionEthyl AcetateOrange solutionColorless solutionLight-green solutionOrange solutionRed-orange upper layer, orange lower layerBlood red solutionGroups 5 & 6Dichromate TestTollens TestLucas TestDNPH TestIodoform TestHydroxamic Acid Testn-PropanolBlue green solutionColorless solution2 layers, clear and colorlessOrange solutionColorless solutionColorless solution; orange precipitate2-PropanolBlue-green solutionColorless solution2 layers; clear and colorlessOrange solutionColorless solutionColorless solution; orange precipitate3-ButanolOrange solutionColorless solution2 layers; turbidOrange solution; orange precipitateRed-orange solution; brown precipitateColorless solution; orange precipitateFormalinBlue green solutionGray precipitate cloudy white solutionColorless solutionYellow solution; yellow precipitateColorless solutionYellow solutionAcetoneOrange solutionColorless solutionColorless solutionOrange solution; orange precipitateColorless solutionYellow solutionEthyl AcetateBlue green solutionColorless solutionColorless solutionOrange solutionOrange solution with red upper layerRed solutionGroup 7 & 8Dichromate TestTollens TestLucas TestDNPH TestIodoform TestHydroxamic Acid Testn-PropanolBlue-green solutionColorless, no precipitateNo layers, no turbidityYellow solutionColorless solutionYellow solution2-PropanolBlue-green solutionColorless, no precipitateNo layers, no turbidityYellow solutionColorless solutionYellow solution with red-orange precipitate3-ButanolOrange solutionColorless, no precipitateTurbid Red-orange precipitateOrange solutionYellow solutionFormalinBlue-green solutionMetallic silver precipitate in colorless solutionNo layers. No turbidityYellow solution with yellow precipitateColorless solutionRed-orange solutionAcetoneOrange solutionColorless, no precipitateNo layers, no turbidityYellow solution with yellow precipitateColorless solution with green precipitateYellow solution with red-orange precipitateEthyl AcetateOrange solution; after 15 mins, turbid upper layer & dark brown lower layerColorless, no precipitateNo layers, no turbidityDark yellow solutionDark yellow lower layer and red-orange upper layerDark red solutionGroup 9 & 10Dichromate TestTollens TestLucas TestDNPH TestIodoform TestHydroxamic Acid Testn-PropanolDark blue green solutionColorless ColorlessOrange solutionColorlessUL-Dark yellowLL-colorless2-PropanolUL- Blue greenLL- ColorlessColorlessColorlessOrange solutionColorlessLight yellow solution3-ButanolLight orange solutionGray precipitate in colorless solutionUL-TurbidLL-ColorlessOrange precipitate in orange solutionDark red precipitate in orange solutionUL- Yellow solutionLL-Colorless solutionFormalinLight blue green solutionSilver mirror solutionColorlessYellow precipitate in yellow solutionColorlessLight reddish brown solutionAcetoneOrange solutionColorlessColorless Orange precipitate in orange solutionYellow green precipitate in colorless solutionUL- Light yellow solutionLL- Cloudy orange solutionEthyl AcetateUL- Cloudy orange solutionLL- Dark orangecolorlessColorless Orange solutionUL- orange solutionLL-Light orange solutionRed violet solutionSummaryDichromate TestTollens TestLucas TestDNPH Test Iodoform TestHydroxamic Acid Testn-PropanolBlue green solutionColorless solutionColorless solutionOrange solutionColorless solutionYellow solution2-PropanolBlue-green solutionColorless solutionColorless solutionOrange solutionColorless solutionColorless/Yellow solution3-ButanolOrange solutionColorless solutionTurbidOrange precipitate in orange solutionBrown precipitate in orange solutionYellow solutionFormalinBlue-green solutionSilver precipitate in colorless solutionColorless solutionYellow precipitate in yellow solutionColorless solutionYellow solutionAcetoneOrange solutionColorless solutionColorless solutionOrange solution in orange precipitateYellow/green precipitate in colorless solutionOrange precipitate in orange solutionEthyl AcetateOrange solutionColorless solutionColorless solution Orange solutionUL- Red- orangeLL- orangeDark red solutionSources of Error:Contamination of reagents due to chemical remains from previous experimentMedicine droppers were contaminated due to being used twice or more in different chemicalsInsufficient or excess amount of heat in some tests Conclusions:Objectives:Differentiate the various types of oxygen-bearing organic compoundDevice a scheme to distinguish each functional groupCharacterize an unknown sample through parallel chemical tests

Primary alcoholSecondary alcoholTertiary alcoholAldehydeKetone

Referenceshttp://www.organicchem.org/alcohols/reactions_of_alcohols/the_oxidation_of _alcoholshttp://www.chemguide/carbonyls/addeli m.htmlhttp://www.chemguide/carbonyls/iodoform.htmlhttp://www.reagenssi.kemia.helsinki.fi/nettilabria/tiedostot/introductory_course_analysis.pdf