Ch 05 Carboxylic Acids And Esters

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Chapter 5 Carboxylic Acids and EstersChapter 5Carboxylic Acids and EstersChapter Objectives: Learn to recognize the carboxylic acid, ester, and related functional groups. Learn the IUPAC system for naming carboxylic acids and esters. Learn the important physical properties of the carboxylic acids and esters. Learn the major chemical reaction of carboxylic acids and esters, and learn how topredict the products of ester synthesis and hydrolysis reactions. Learn some of the important properties of condensation polymers, especially thepolyesters.Mr. Kevin A. BoudreauxAngelo State UniversityCHEM 2353 Fundamentals of Organic ChemistryOrganic and Biochemistry for Today (Seager & Slabaugh)www.angelo.edu/faculty/kboudreaCarboxylic Acids Carboxylic acids are weak organic acids whichcontain the carboxyl group (RCO2H):OCOOHOa carboxylic acidCRCOHHRCOOHRCO2Hcondensed ways ofwriting the carboxylgroupOthe carboxyl group The tart flavor of sour-tasting foods is often causedby the presence of carboxylic acids.2

Chapter 5 Carboxylic Acids and EstersNomenclature ofCarboxylic Acids3Nomenclature of Carboxylic Acids Select the longest carbon chain containing thecarboxyl group. The -e ending of the parent alkanename is replaced by the suffix -oic acid. The carboxyl carbon is always numbered “1” but thenumber is not included in the name. Name the substituents attached to the chain in theusual way. Aromatic carboxylic acids (i.e., with a CO2Hdirectly connected to a benzene ring) are namedafter the parent compound, benzoic acid.OCOHBenzoic acid4

Chapter 5 Carboxylic Acids and EstersExamples: Naming Carboxylic Acids Name the following ples: Naming Carboxylic Acids Name the following 2COHCH2CH2CH36

Chapter 5 Carboxylic Acids and EstersExamples: Naming Carboxylic Acids Name the following compounds:OCCH3 OOHCH3CCH3CHCH3COHCH2CH2CHCH37Examples: Naming Carboxylic Acids Name the following compounds:CH3CO2HOCOHOCH3COHCH3CHCH3Cl8

Chapter 5 Carboxylic Acids and EstersMore Complicated Acids For molecules with two carboxylic acid groups thecarbon chain in between the two carboxyl groups(including the carboxyl carbons) is used as thelongest chain; the suffix -dioic acid is used. For molecules with more than two carboxylic acidgroups, the carboxyl groups are named as carboxylicacid substituents.OOOHOCCOHHOethanedioic arboxylic acidpropanedioic acid9Examples: Drawing Carboxylic Acids Draw structural formulas for the following molecules:– 2-methylpropanoic acid– 2,2,5-trimethylhexanoic acid– 4,5-dimethyl-3-nitrooctanoic acid10

Chapter 5 Carboxylic Acids and EstersExamples: Drawing Carboxylic Acids Draw structural formulas for the following molecules:– para-bromobenzoic acid– 2,4,6-trinitrobenzoic acid– 4-ethylpentanedioic acid(what’s wrong with this name?)1112

Chapter 5 Carboxylic Acids and EstersPhysical Properties ofCarboxylic Acids13Physical Properties of Carboxylic Acids Carboxylic acids hydrogen bond to themselves toform a dimer:ORHOCCOHRO Carboxylic acids also form hydrogen bonds towater molecules:HHOORCHOHOH14

Chapter 5 Carboxylic Acids and EstersPhysical Properties of Carboxylic Acids Since carboxylic acids can form more than one set ofhydrogen bonds, their boiling points are usuallyhigher than those of other molecules of the samemolecular weight (MW). Low-MW carboxylic acids are generally liquids atroom temp. (often, they are somewhat oily); higherMW carboxylic acids are generally waxy solids. Carboxylic acids with 12 to 20 carbon atoms areoften referred to as fatty acids, since they are foundin the triglycerides in fats and oils (more later). Short-chain carboxylic acids are also generally moresoluble in water than compounds of similar MW,since they can hydrogen bond to more than onewater molecule.15Physical Properties of Carboxylic Acids As the number of carbons in a carboxylic acid seriesbecomes greater, the boiling point increases and thesolubility in water decreases. Many carboxylic acids that are liquids at roomtemperature have characteristically sharp orunpleasant odors.– Ethanoic acid/acetic acid is the main ingredient invinegar.– Butanoic acid is partially responsible for the odorof locker rooms and unwashed socks.– Hexanoic acid is responsible for the odor ofLimburger cheese. Like most acids, carboxylic acids tend to have a sourtaste (e.g., vinegar, citric acid, etc.)16

Chapter 5 Carboxylic Acids and EstersTable 5.2CommonNameFormic acidAcetic acidPropionic acidButyric acidValeric acidCaproic acidCaprylic acidCapric acidLauric acidMyristic acidPalmitic acidStearic acidPhysical properties of some carboxylic HBP( C)101118141164186205239270299Dec.Dec.Dec.MP( C)817-21-5-34-3173244586371Solubility(g/100 mL g Points of Various Functional GroupsFigure 5.4The boiling points ofcarboxylic acids comparedto 1 alcohols, aldehydesand ketones, ethers andalkanes.18

Chapter 5 Carboxylic Acids and EstersComparing Physical PropertiesBoiling Point:Carboxylic r Solubility:Carboxylic r Boiling Solubility in waterweightpointPentane72 g/mol35 CInsolubleDiethyl ether74 g/mol35 CInsolubleButanal72 g/mol76 C7.1 g / 100 mL H2O1-ButanolPropanoic acid74 g/mol74 g/mol118 C141 C9.1 g / 100 mL H2OInfinite19Examples: Predicting Physical Properties Arrange the following compounds in order ofincreasing boiling point. (All of the compoundshave about the same molecular weight.)– 1-pentanol– hexane– butanoic acid– pentanal Which member of each of the following pairs ofcompounds would you expect to have a highersolubility in water?– 2-butanone or propanoic acid– hexanoic acid or ethanoic acid20

Chapter 5 Carboxylic Acids and EstersSome ImportantCarboxylic Acids21Important Carboxylic AcidsHCOOOCH3OHCCH3CH2OHEthanoic acid(Acetic acid)(from Latin acetum, vinegar)Vinegar is a 5% solution ofacetic acid dissolved in water;acetic acid is also responsiblefor the taste of sour wine (fromthe oxidation of ethanol) andsourdough breadMethanoic acid(Formic acid)(from Latin formica, ant)A component of the venomof ants and caterpillars;produced in the body whenmethanol is consumedCOHPropanoic acid(Propionic acid)Found in Swiss cheese;salts of this acid are usedas mold inhibitorsOOCH3CH2CH2COHButanoic acid(Butyric acid)(from Latin butyrum, butter)This acid has a foul, rancid odor;produced from the breakdown ofsoft triglycerides in butterCH3CH2CH2CH2CH2COHHexanoic acid(Caproic acid)Responsible for the odor ofLimburger cheese.22

Chapter 5 Carboxylic Acids and arboxylic acid(Citric acid)Found in citrus fruits (lemons, grapefruit,oranges, etc.); commonly used in bufferingsolutions with sodium citrateOOHOOHOxalic acidFound in many leafy green plantssuch as rhubarb and spinach;combines with calcium ions in thebody to produce insoluble salts,which form kidney stonespara-Aminobenzoic aid (PABA)Used in sunscreens; absorbsshort-wavelength UV light. It is also requiredby bacteria for the production of folic acid,needed to maintain the growth of healthy cellwalls; sulfa drugs block the uptake of PABAby bacteria, causing them to be unable tomanufacture folic acid, and thus preventingthe bacteria from multiplyingOOHOOHTerephthalic acidA white, crystalline solid; used inthe manufacture of somepolyesters23OHOOHGlycolic acidAn alpha-hydroxy acid used incosmetics and skin creams;alpha-hydroxy acids are thought toloosen the cells of the epidermis andaccelerate the flaking off of dead skin;however these compounds can increasethe skin's sensitivity to UV lightOHOOHOOHMalic acidResponsible for the sharptaste of apples (genus Malus)OOHOH2-hydroxypropanoic acid(Lactic acid)Produced from the fermentation of sugarsunder anaerobic conditions; found in sweat,sour milk, fermented pickles, sauerkraut,and yogurt; produced in muscles fromglucose under anaerobic conditions (thebuildup of lactic acid leads to a heavy, weakfeeling, and muscle cramps); produced afterdeath during the breakdown of sugars in thebody by bacteria, inactivating the enzymesthat allow the transport of calcium ions,causing rigor mortis24

Chapter 5 Carboxylic Acids and EstersOOHOHOOHOHONNiacinA water-soluble, B-Complex vitamin obtainedfrom fish, green vegetables, lean meat, poultry,whole-grain and enriched bread and cereal;produced in the body from tryptophan;essential for growth, healthy tissues, theproduction of energy from carbohydrates, andthe production of fatsOHTartaric acidFound naturally in wine, and isresponsible for some of the sharp taste ofwine; it is added to many sour-tastingsweet foods. The potassium salt, creamof tartar, has many cooking applications;the potassium-sodium salt, Rochelle salt,is a mild laxative.OOHOHOOHOHOOSuccinic acidAn intermediate along thecitric acid cycleFumaric acidOccurs naturally in many plants, and is essential forvegetable and animal tissue respiration; used in bakingpowders, and in some fruit drinks as a replacement forcitric acid25OH2NOHGamma-aminobutanoic acid (GABA)A inhibitory neurotransmitter; ethanol binds to the sameprotein as GABA at a neighboring location, distorting theprotein so that GABA binds more easily, further inhibiting thecell from firing; benzodiazepines such as Valium also bind tothe same protein but at a different site, inhibiting the cell stillfurther, and sometimes with deadly consequencesOHONOHOOHPantothenic acidA water-soluble B-complex vitamin;converted by the body intoCoenzyme A, which helps the bodyproduce energy from foodOHOO- Na HONH2Monosodium Glutamate (MSG)The sodium salt of the amino acid glutamate;produced in meat during the decomposition ofproteins; with inosine monophosphate (IMP), oneof the major substances responsible for the flavorof meat; MSG is also added to some foods toenhance their meaty flavor26

Chapter 5 Carboxylic Acids and EstersChemical Properties ofCarboxylic Acids27Acids and Bases Acids:– have a sour taste.– react with active metals to produce H2 gas.– turn blue litmus red. Bases:– have a bitter taste and a slippery feel.– turn red litmus blue. When they react with each other, acids and basescancel each others properties in a neutralizationreaction:acid base salt water28

Chapter 5 Carboxylic Acids and EstersAcids An acid gives a proton (H ) to another species.Acids produce hydronium ions, H3O , when theyare dissolved in water:H—A H2O A– H3O A strong acid is one that completely dissociates inwater (i.e., every molecule of the acid splits apart):H—Cl H2O Cl– H3O A weak acid is one in which only a smallpercentage of the molecules are dissociated at anyone time (in other words, there is also a backwardsreaction, where the acid molecule is regenerated):H—F H2O h F– H3O 29The pH Scale The acidity of a solution is measuredusing the pH scale. The pH of asolution is defined aspH - log[H3O ]Acidic:pH 7.00[H3O ] [OH-]Basic:pH 7.00[H3O ] [OH-]Neutral: pH 7.00[H3O ] [OH-]30

Chapter 5 Carboxylic Acids and EstersThe Acidity of Carboxylic Acids Carboxylic acids are weak acids; in water, theydissociate to produce hydronium ions andcarboxylate ions:OROOH CH2Ocarboxylic acidRC OH3Ocarboxylate ion A 1.0 M solution of acetic acid is about 0.5%dissociated into hydronium and acetate ions:OCH3OCOH H2OCCH3acetic acidO H3Oacetate ion31The Acidity of Carboxylic Acids The dissociation of a carboxylic acid is a reversiblereaction, and the position of the equilibrium can beaffected by the addition of acid (low pH) or byadding base (high pH):OR H2OCOObase(high pH)Hcarboxylic acidacid(low pH)R H 3OCOcarboxylate ion At the physiological pH of 7.4 (the pH of most bodyfluids) the carboxylate form of most carboxylic acidsis the predominate form.32

Chapter 5 Carboxylic Acids and EstersCarboxylate Salts33Carboxylate Salts Carboxylic acids react with strong bases such assodium hydroxide (NaOH) and potassium hydroxide(KOH) to produce carboxylate salts. Carboxylate salts are named by naming the metalfirst, and changing the -ic acid ending of thecarboxylic acid name to -ate.ORCOOH NaOHcarboxylic acidbaseRC O- Na H2Ometal carboxylateOCH3COO- Na sodium ethanoate(sodium acetate)CH3CH2CH2CH2CO- NH4 34

Chapter 5 Carboxylic Acids and EstersExamples: Carboxylate Salts Draw the structure of pyruvate, the form of pyruvicacid which is found as an intermediate in energyconversion reactions in living organisms.CH3OOCCOHpyruvic acid Complete the following reactions and name thecarboxylate salt products.OCH3COH NaOHOHOCCH3CH2CHCH3 NaOH35Examples: Carboxylate Salts Complete the following reactions and name thecarboxylate salt products.OCOH NaOHOCOH KOHCH336

Chapter 5 Carboxylic Acids and EstersPhysical Properties of Carboxylate Salts Carboxylate salts are ionic compounds, and aretypically solids at room temperature. Because they contain charges, carboxylate salts aretypically much more soluble in water than thecarboxylic acids from which they are derived.– This is important in the formation of soaps (morelater).OCH3(CH2)16COOH NaOHCH3(CH2)16CO- Na H2OSodium stearate(sodium octadecanoate)soluble in waterStearic acid(octadecanoic acid)insoluble in waterfound in beef fat andsome butters37Important Carboxylate SaltsOOO- Na O- Na Sodium propanoate--2Calcium propanoateCommonly usedpreservatives; foundin bread, cakes, andcheesesCH3ONNCH3Zinc 10-undecylenateUsed to treat athlete's foot (Desenex)2 O NaHOC2H5 O- Zn2 O Na-Sodium citrateThe sodium salt of citric acid, sodium citrate, isused in buffers with citric acid to maintaindesirable characteristics of foams and gels (jelly,ice cream, candy, whipped cream, etc.) bycontrolling the pH of the product; also used inmedicines and blood for transfusions; alsofunctions as an anticoagulant in bloodO- Ca2 OONa OOOSodium benzoateFound in cranberries andprunes; commonly usedas a preservative inbaked goods, ketchup,carbonated beverages,etc.OHO-OC2H5Denatonium benzoate ('Bitrex')Benzyl diethyl ((2,6-xylylcarbamoyl)methyl) ammoniumbenzoateDiscovered in 1958, this is the bitterest-tasting compoundknown; as little as ten parts per million make substancesunbearably bitter to most humans. It is used as an aversiveagent, an additive that prevents accidental ingestion of atoxic substance. It is used to denature ethanol, methanol,and rubbing alcohol, and well as solvents, paints, arnishes,antifreeze, etc.38

Chapter 5 Carboxylic Acids and EstersEsters39Esters An ester (“carboxylic ester” in the textbook) is aderivative of a carboxylic acid in which there is acarbon group connected to the single-bondedoxygen:ORCester linkageOOR'RCOCcarbon group40

Chapter 5 Carboxylic Acids and EstersNomenclature of EstersORCacid partOR'alcohol part Name the alkyl or aromatic portion contributed bythe “alcohol part” first. The “acid part” is named as a carboxylic acid, withthe -ic acid suffix changed to -ate.OCH3COOCH3CH3CH2CH2COCH2CH341Examples: Ester Nomenclature Name the following compounds:CH3 OCH3CHCOOCH3HOCH3CH2OCCOCH3CH2CH3CH2CH2CHCH342

Chapter 5 Carboxylic Acids and EstersExamples: Ester Nomenclature Name the following ples: Ester Nomenclature Name the following compounds:OCH3CH2CH2COCH3OCOCH344

Chapter 5 Carboxylic Acids and EstersExamples: Drawing Esters Draw structural formulas for the following molecules:– methyl butanoate– ethyl 2-methylpropanoate– methyl 2,4-dimethylhexanoate45Examples: Drawing Esters Draw structural formulas for the following molecules:– propyl 2,2,3,4-tetramethylhexanoate– isopropyl benzoate– methyl para-nitrobenzoate46

Chapter 5 Carboxylic Acids and EstersSome Important Esters47Important EstersHOOHOHOOOHOOHVitamin C (ascorbic acid)A water-soluble vitamin found in citrusfruits; prevents scurvy; essential for healthyblood vessels, bones, and teeth; helpsform collagen, a protein that holds tissuestogetherOO–OONOPeroxyacetyl nitrate (PAN)Produced by the action of sunlight onfragments of unburnt hydrocarbon fuel,oxygen, and nitrogen dioxide; one of theirritants (lachrymator) found inphotochemical smogAmyl acetateAlso known as banana oil and pear oil; thecommercially available compound is amixture of amyl (pentyl) isomersOCH3CH3 NOCH3Acetylcholinean important neurotransmitterOOBenzyl acetateoil of jasmine48

Chapter 5 Carboxylic Acids and EstersOOHOOCoumarinFound in lavenderoil, sweet cloverand tonka beansOOGeranyl acetategeranium oilOOWarfarinA potent rodenticideOOCH3(CH2)14O(CH2)15CH3SpermacetiAlso known as cetyl palmitate; found inthe spermaceti organ or case above theskull of the sperm whale (Physetermacrocephalus). Its exact function is notknown but it may be used as"cushioning," allowing the whale's head tobe used as a battering ram in fightsbetween males (see Moby Dick), as aregulator of the whale's buoyancy inwater, or as an aid in echolocation infocusing sound waves. Spermaceti washighly sought by whalers in the 18th and19th centuries, and was widely used49commercially.OCH3OHMethyl salicylateAlso known as oil of wintergreen and betulaoil; used as a flavoring and as an ingredientin deep heating rubs. It also fluoresces underultraviolet light, producing visible blue light.This is most apparent in Wint-O-GreenLifesavers, which contain methyl salicylateas their flavoring. It is also used in somesunscreen lotionsPolymers with Ester GroupsOOOCNMethyl cyanoacrylatePolymerizes on contact withsurfaces containing traceamounts of water andalcohols to form Superglue;superglue is also used insurgery in place of sutures,and by morticians to sealthe eyes and lips of theirclientsOOMethyl acrylate (vinylacetate)Polymerizes to form polyvinylacetate; used in acrylic paintsin combination with pigmentsand a surfactant which causesthe polymer to be suspended inan emulsion; also used insafety glass (a layer of PVAsandwiched between twolayers of glass) and chewinggumOOOMethyl methacrylatePolymerizes to formpoly(methyl methacrylate);trade names are Lucite,Plexiglass, and Perspex;the bulky methyl and methylester groups cause thepolymer to be orientedchaotically within the solidpolymer, allowing light topass through withoutscattering, rendering theplastic transparentLauryl methacrylateUsed to make the polymer poly(laurylmethacrylate); used as an additive inviscostatic engine oils, which keepsthe oild viscous at high temperatures.50

Chapter 5 Carboxylic Acids and EstersReactions of Esters51Synthesis of Esters: Esterification Reactions The simplest way to synthesize an ester is to heat acarboxylic acid with an alcohol or phenol (plus anacid catalyst); the oxygen of the alcohol adds to thecarboxyl group, splitting out a molecule of water inthe process (an esterification reaction).OOCRH HOa carboxylicacidOR'an alcoholora phenolH CRR' HOHOan ester52

Chapter 5 Carboxylic Acids and EstersSynthesis of Esters: Esterification Reactions Since this reaction is a reversible reaction, it oftenreaches an equilibrium with a large amount ofunreacted starting material still present. Better yields are obtained using either acidchlorides or acid anhydrides as starting materials.These reactions are nonreversible.OOCROCClCRORacid anhydrideacid chloride53Synthesis of Esters: Esterification ReactionsOOCR HORan alcoholora phenolacid chlorideOan esterO HOCOacid anhydrideClOOCRR' HCR'ClRR' CR'an alcoholora phenolOROan esterHCROa carboxylicacid54

Chapter 5 Carboxylic Acids and EstersExamples: Esterification Reactions Write both products of the following reactions:OCH3CH2CH2OH CH3CH2OHCOCH3CH OHCl 55Examples: Esterification Reactions Write both products of the following reactions:OOCH3COCCH3 CH3CH2OH56

Chapter 5 Carboxylic Acids and EstersExamples: Esterification Reactions Write both products of the following reactions:OHOCH3Cl CH3CCHCH357Examples: Esterification Reactions Write both products of the following reactions:OOOCOH CH3COCCH3OH58

Chapter 5 Carboxylic Acids and EstersPain, Pain, Go AwayOOOHOHOOHOSalicylic acidFound in the bark of the willowtree (Salix); a tea brewed fromthe bark reduces fever andrelives pain and inflammation,but is very acidic, and causesirritation of the mucousmembranes in the mouth, throat,and stomach, and can causepainful ulcers and stomachbleedingCH3Aspirin (acetylsalicylic acid)Produced by reacting salicylic acid with aceticanhydride, giving a compound which is lessacidic, and does not cause as much irritation,but still retains all of the beneficial medicalproperties; aspirin seems to work by blockingthe production of prostaglandins, hormoneswhich may be responsible for producing pain,fever and inflammation; one of the mostcommonly used pharmaceutical drugs; over 40million pounds are produced in the UnitedStates per year59More Pain RelieversOOHNCH3OHOOHAcetominophenDoes not cause stomachirritation, and hasanalgesic and antipyreticproperties that are similarto aspirin, but noanti-inflammatoryfunctions; available underthe trade names Tylenol,Excedrin Aspirin Free,Panadol, and Anacin-3OHCH3OIbuprofenAn analgesic, antipyretic,and anti-inflammatorydrug; it is also notirritating to the stomachlining; available under thetrade names Motrin,Advil, Ibuprin, Nuprin, andMediprinNaproxenAn analgesic, anti-pyretic,and anti-inflammatorydrug; active ingredient inAleve60

Chapter 5 Carboxylic Acids and EstersCondensation Polymers: Polyesters Condensation polymers are polymers which formwith the loss of a small molecule (typically water orHCl). Condensation polymers, such as polyesters andpolyamides (Nylon, Ch. 6), form when each of themonomers contain two of the same functional group,so the reaction can take place at both ends.61Condensation Polymers: PolyestersOHOCH2CH2OHEthylene glycolOHOCH2CH2OHCCOHHOEthylene glycolTerephthalic OCCOCH2CH2OCOH62

Chapter 5 Carboxylic Acids and EstersCondensation Polymers: PolyestersOOCHCOOCH2CH2 OHnPolyethylene terephthalate(PET)A polyesterOver 3 billion pounds of PET are made every year. It forms avery linear chain, and is very inert. It can be melted and pulledthrough spinnerettes to make fibers, threads, or yarn (Dacron,Fortrel, Terylene), where it can be used in automobile tire cord,permanent press clothing, sutures, replacements for damagedsections of blood vessels and the esophagus, etc. PET melts canalso be forced through narrow slits to produce thin sheets orribbons known as Mylar; this form is used as the supportmedium in audio and video tape.63Reactions of Esters: Ester Hydrolysis Esters may be broken apart under acidic conditionsby water (a hydrolysis reaction) to form acarboxylic acid and an alcohol.OO HRCOR' H2Oan esterRCOH a carboxylic acidR'OHan alcohol This is essentially the reverse reaction of thesynthesis of esters from carboxylic acids andalcohols.64

Chapter 5 Carboxylic Acids and EstersReactions of Esters: Saponification Esters may be broken apart under basic conditionsby sodium hydroxide (lye) or potassium hydroxideto form carboxylate salts and alcohols.OROCOR' NaOHan esterbaseRCO- Na a carboxylate saltR'OHan alcohol This reaction is important in the production ofsoaps.65Examples: Splitting Esters(Because Breaking Up Is Hard To Do) Complete the following reactions:OH CH3COCH2CH3 H2OOCH3COCH2CH3 NaOH66

Chapter 5 Carboxylic Acids and EstersTriglycerides and Soaps67Triglycerides Long-chain carboxylic acids, often referred to asfatty acids, are stored by living organisms bycombining them with glycerol to produce tri-esterscalled triglycerides. Triglycerides at room temperature are usually eithersolids or semi-solids (fats), or viscous liquids c acid(a fatty 3glyceryl tristearate (tristearin)a triglyceride68

Chapter 5 Carboxylic Acids and EstersSome Saturated Fatty AcidsOOHStearic acidA saturated fatty acid found in lard, beef fat,butterfat, cottonseed oil; the sodium salt, producedby heating lard with sodium hydroxide, can be usedas a soapOOHLauric acidFound in coconut oil;commonly used in soapsOOHMyristic acidA fatty acid found in butterfat,coconut oil, and nutmeg oilOOHArachidic acidA fatty acid found in peanut oil69Some Saturated Fatty AcidsOOHPalmitic acidA fatty acid, found in lard, beef fat, butterfat, and cottonseed oil;the triglycerides in cocoa butter have oleic acid attached to thecentral oxygen, with stearic acid or palmitic acid on the otheroxygens; this more regular composition gives cocoa butter a muchsharper melting point than is usually observed in fats, andchocolate remains brittle almost up to its melting point of 34 C (justbelow body temperature); the sudden melting of chocolate in themouth gives it a pleasant feeling of coolness70

Chapter 5 Carboxylic Acids and EstersSome Unsaturated Fatty AcidsOOHOleic acidAn unsaturated fatty acid; the chain is much less flexible than that ofstearic acid because of the double bond, and cannot pack as tightly,so the triglycerides it forms are oils and not fats; found in olive oil,cocoa butter and chocolate, beef fat, lard, and peanut oilOOHLinolenic acidA omega-6 polyunsaturated fatty acid found in linseed oil and corn oilOOHArachidonic acidAn omega-6 polyunsaturated fatty acid found in corn oil, linseed oil, animal tissues71Some Unsaturated Fatty AcidsOOHEicosapentaenoic acidA omega-3 polyunsaturated fatty acid found in fish oil and seafoods; omega-3 fattyacids may, according to some studies, help to lower the risk of heart diseaseOOHPalmitoleic acidAn unsaturated fatty acid found in butterfat and cod liver oilOOHDocosahexaenoic acidAn omega-3 polyunsaturated fatty acid found in fish oil and seafoods72

Chapter 5 Carboxylic Acids and EstersTriglycerides (Fats and Oils)OOROOOOROROOOOC(CH2)12CH3OTriglyceridesfats and oils (lipids)ROROOROC(CH2)12CH3OTristearinOne of the principlecompounds in beef fat andcocoa butter; triglycerides suchas this lubricate meat fibers,and make the meat moretender when cooked; theyellow color of beef fat comesfrom carotene dissolved intristearin.OC(CH2)12CH3OTrimyristinFound in nutmeg, a spiceobtained from the seed ofthe nutmeg tree, found inIndonesia and the WestIndies, and other 73OOOOOOOOOOOOOOOOOOOOOlestraA substitute for dietary fats developed by Procter & Gamble after 30 years and 200 million dollars worth of research; it is a combination of sucrose and fatty acidsobtained from soybean oil and cottonseed oil; it is too hindered for digestiveenzymes to react with; can carry small amounts of fat-soluble vitamins out ofintestinal tract74

Chapter 5 Carboxylic Acids and EstersSaponification of Triglycerides(Chewing the Fat) Triglycerides can be broken apart under basicconditions (a saponification reaction) to producelong-chain carboxylate salts.OCH2OC(CH2)16CH3OCHOC(CH2)16CH3NaOHNa -OC(CH2)16CH3 CHSodium stearatea carboxylate saltOCH2CH2OCH2OC(CH2)16CH3OHOHOHglycerolglyceryl tristearate (tristearin)a triglyceride Unlike their carboxylic acid forms, the carboxylatesalts are at least somewhat soluble in water.75Fatty Acid Salts Salts of fatty acids combine two different solubilitycharacteristics:– a long, nonpolar, water-insoluble (hydrophobic)hydrocarbon “tail.”– a charged, water-soluble (hydrophilic) “head.”OO- Na Nonpolar, hydrophobic tail(water insoluble)CO2-Polar, hydrophilic head(water soluble) When these substances are placed in water, their“tails” become tangled, thereby dissolving eachother, leaving the charged, hydrophilic portionssticking out into the solution, allowing the wholemicelle to dissolve in water, acting as a soap.76

Chapter 5 Carboxylic Acids and EstersSoap(Cleanliness, As They Say, Is Next To Impossible)CO2-Grease77a soap micelleSoaps and DetergentsOO- Na Sodium stearateOO- 2Ca2 Calcium stearate"soap scum"Sodium Alkylbenzenesulfonatea synthetic detergentSO3- Na Sodium para-Dodecylbenzenesulfonatea biodegradable detergentOPolyoxyethyleneA nonionic synthetic detergent; causes less foaming.SO3- Na OH78

Chapter 5 Carboxylic Acids and EstersEsters of InorganicAcids79Esters of Inorganic AcidsOROHHOPOH OHROPOHan alcoholOHOHphosphoric acida phosphate ester(monoester)ROORROPOHORORa phosphate triesterOHROPOHORa phosphate diester80

Chapter 5 Carboxylic Acids and EstersSome Important Phosphate EstersOOCH2O P OOOOHROOPOO-OPOO-PO-O-a phosphate nineOOPO-ONNCH2OO-RiboseAdenosine TriPhosphate (ATP)OHOH81NH2NNadenineO-OONNO CH2PNH2Odeoxyribose-NcytosineO-OPOO CH2NOOONHNO-OPH2NO CH2guanineNNOOOCH3HNthymineO-ODeoxyribonucleic Acid(DNA)POO CH2NOO82OH

Chapter 5 Carboxylic Acids and EstersReactions of Carboxylic Acids1. Reaction of a carboxylic acid with water to form a carboxylate ion.OOR H2OCR H3OC Ocarboxylate ionO Hcarboxylic acid2. Reaction of a carboxylic acid with a base to form a carboxylate salt and water.OOR NaOHCR H2OC- O Nacarboxylate saltO Hcarboxylic acid3. Reaction of a carboxylic acid with an alcohol to produce an ester and water.OOH CH H O R'CR' H O H ROROalcoholestercarboxylic acidor phenol4. Reaction of an acid chloride with an alcohol to produce an ester and HCl.OOCRClacid chloride H O R'alcoholor phenolCRR' H ClOester835. Reaction of an acid anhydride with an alcohol to produce an ester and a carboxylic acid.OOOO CORacid anhydrideCRH O R'alcoholor ph

Chapter 5 Carboxylic Acids and Esters 17 Common Name Structural Formula BP ( C) MP ( C) Solubility (g/100 mL H2O) Formic acid H—CO2H 101 8 Infinite Acetic acid CH3—CO2H 118 17 Infinite Propionic acid CH3CH2—CO2H 141 -21 Infinite Butyric acid CH3(CH2)2—CO2H 164 -5 Infinite Valeric acid CH 3(CH2)

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The acylating reagents: carboxylic acid anhydride, acid chlorides, carboxylic acids, esters, thioesters. Classification of poly- and heterofunctional compounds. Polyalcohols, dihydric phenols, dicarboxylic acids, amino alcohols, amino phenols, hy-droxy-acids, oxo-acids (aldehyde and keto acids). Examples. Acid-base prop-erties.

UNIT 12 ALDEHYDES KETONES AND CARBOXYLIC ACIDS 1) What are aldehydes ? 1 Aldehydes are the organic compounds containing carbonyl group,linked with one hydrogen and one alkyl /aryl group. 2) What are carboxylic acids? 1 Carboxylic acids are the organic compounds containing carboxyl(-COOH) group/s 3) Between aldehyde and ketones which one is .

Lithium aluminium hydride will also reduce ketones, aldehydes esters, nitriles, amides, acid chlorides alkyl halides, epoxides and nitro groups Borane reacts most rapidly with carboxylic acids to give primary alcohols and it is possible to reduce carboxylic acids in the presence of some oth

10 tThe carboxyl group is the parent group of a family of compounds called acyl compounds or carboxylic acid derivatives tEsters are named from the corresponding carboxylic acid and alcohol from which the ester would be made lThe alcohol portion is named first and has the ending -yl lThe carboxylic acid is na

Ch21 Carboxylic acid Derivatives(landscape).docx Page 1 Carboxylic acid Derivatives Carboxylic acid derivatives are described as compounds that can be converted to carboxylic acids via simple acidic or basic hydrolysis. The most important acid derivatives are esters, amides and nitriles, although acid halides and anhydrides are also derivatives (really activated forms of a File Size: 2MB

Properties of Acids and Bases Return to the Table of contents Slide 5 / 208 What is an Acid? Acids release hydrogen ions into solutions Acids neutralize bases in a neutralization reaction. Acids corrode active metals. Acids turn blue litmus to red. Acids taste sour. Properties of Acids Slide 6 / 208 Properties

Oxy acids or ternary acids have the hydrogen attached to an oxygen atom: Carboxylic acids have COOH group the hydrogen attached to the COO group is acidic: *ADD THE LONE PAIR ELECTRONS TO THE PICTURES OF SULFURIC ACID, NITRIC ACID AND CARBOXYLIC ACID GROUP. Structure of Ba