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Chapter 12 Organic Compounds with Oxygen and Sulfur 12.1 Alcohols, Thiols, and Ethers 1 Alcohols An alcohol contains a hydroxyl group (—OH) attached to a carbon chain. A phenol contains a hydroxyl group (—OH) attached to a benzene ring. 2 Naming Alcohols The names of alcohols • in the IUPAC system replace the -e with -ol. • with common names use the name of the alkyl group followed by alcohol. Formula IUPAC CH4 methane CH3─OH methanol CH3─CH3 ethane CH3─CH2─OH ethanol Common Name methyl alcohol ethyl alcohol 3 More Names of Alcohols IUPAC names for longer chains number the chain from the end nearest the -OH group. CH3─CH2─CH2─OH 1-propanol OH │ CH3─CH─CH2─CH3 2-butanol CH3 OH │ │ CH3─CH─CH2─CH2─CH─CH3 5-methyl-2-hexanol 6 5 4 3 2 1 4 Some Typical Alcohols OH | “Rubbing alcohol” CH3—CH—CH3 2-propanol (isopropyl alcohol) Antifreeze HO—CH2—CH2—OH 1,2-ethanediol (ethylene glycol) OH | Glycerol HO—CH2—CH—CH2—OH 1,2,3-propanetriol 5 Phenols in Medicine Phenol • is the IUPAC name for benzene with a hydroxyl group. • is used in antiseptics and disinfectants. OH OH OH OH OH CH2CH2CH2CH2CH2CH3 Phenol Resorcinol 4-hexylresorcinol Carbolic Acid 8 Derivatives of Phenol Compounds of phenol are the active ingredients in the essential oils of nutmeg, thyme, cloves, and vanilla. OH OH OCH3 CH=CHCH3 isoeugenol (nutmeg) H C CH3 CH3 thymol (thyme) OH OH CH3 OCH3 OCH3 CH2CH=CH2 eugenol (cloves) H C O vanillin (vanilla) 9 Common Phenols/Alcohols Cl Cl OH Cl Cl HO Cl CH2 Cl ortho-phenylphenol (Lysol) C OH C OH 3,3',5,5',6,6'-hexachlorodiphenylmethane (hexachlorophene) C C C C C C C C C C OH trailmarker for termites HO CH2CH2CH2CH2CH2CH3 n-hexylresorcinol (sucrets) 10 Common Phenols/Alcohols C C C OH OH Cl H C C Cl C sex pheromone for male Boll Weevil C C C C C C C OH C C sex pheromone for Bark Beetle sex attractant for lonestar tick OH C C C C C aggregating pheromone for Bark Beetle 11 C Common Phenols OH OH (CH2)7 CH CH (CH2)5 CH3 oil of Poison Ivy 12 Herbicides produced by Phenols Cl Cl O O C C OH 2,4-dichlorophenoxy acetic acid (2,4-D) Cl Cl O O Cl C C OH 2,4,5-trichlorophenoxy acetic acid (2,4,5-T) 13 Learning Check Write the structure of each of the following: A. 3-pentanol B. ethyl alcohol C. para-methylphenol 15 Solution Write the structure of each of the following: A. 3-pentanol OH | CH3—CH2—CH—CH2—CH3 B. ethyl alcohol CH3—CH2—OH OH C. para-methylphenol CH3 16 Thiols Thiols • contain sulfur • are similar to alcohols • contain a thiol (-SH) group • often have strong odors • found in cheese, onions, garlic, and oysters • are used to detect gas leaks 17 Thiols are named in the IUPAC system by adding thiol to the alkane name of the longest carbon chain. (Methyl Mercaptan) 18 18 19 Striped Skunk (Mephitis mephitis) Thiols H CH2SH C C CH3 E-2-buten-1-thiol 38-44% 3-methyl-1-butanethiol 18-26% H CH3 CH3CHCH2CH2SH 2-quinolinemethanethiol N 3-12% CH2SH 20 For pets that have been sprayed, bathe the animal in a mixture of 1 quart of 3% hydrogen peroxide (from drug store), 1/4 cup of baking soda (sodium bicarbonate) and a teaspoon of liquid detergent. After 5 minutes rinse the animal with water. Repeat if necessary. The mixture must be used after mixing and will not work if it is stored for any length of time. DO NOT STORE IN A CLOSED CONTAINER - it releases oxygen gas so it could break the container. This mixture may bleach the pet's hair. 21 Why tomato juice is believed to eliminate skunk odor. Bathing an animal in tomato juice seems to work because at high doses of skunk spray the human nose quits smelling the odor (olfactory fatigue). When this happens, the odor of tomato juice can easily be detected. A person suffering olfactory fatigue to skunk spray will swear that the skunk odor is gone and was neutralized by the tomato juice. Another person coming on the scene at this point will readily confirm that the skunk spray has not been neutralized by the tomato juice. 22 Quickly And Safely Eliminates Odors On Pets Thiotrol Spray is specially formulated to neutralize, not mask, offensive skunk odor on pets, people, clothing, carpets, and other contaminated surfaces. Directions Completely saturate affected areas with the high output pump sprayer. Work into fur, clothing, or carpet and allow to dry. Resaturate affected area and let dry. To avoid eyes, apply to face using a saturated cloth. Should any odors remain, locate odor source and reapply. Thiotrol Spray Caution For topical use only. Avoid contact with eyes. Sold Exclusively Through Veterinarians Ethers An ether • contains an ─O─ between two carbon groups. • has a common name that gives the alkyl names of the attached groups, followed by ether. CH3─O─CH3 CH3─CH2─O─CH3 dimethyl ether ethyl methyl ether Propyl People Ether 24 Ethers as Anesthetics Anesthetics • inhibit pain signals to the brain. • like diethyl ether, CH3─CH2─O─CH2─CH3, were used for over a century, but caused nausea and were flammable. • developed by the 1960s were nonflammable. F F C F O F F C C F H Ethrane (enflurane) Cl Cl Cl F C C H F H O C H H Penthrane 25 Chapter 12 Organic Compounds with Oxygen and Sulfur 12.2 Properties of Alcohols and Ethers 26 Boiling Points of Alcohols Alcohols • contain polar OH groups. • form hydrogen bonds with other alcohol molecules. • have higher boiling points than alkanes and ethers of similar mass. 27 Boiling Points of Ethers Ethers • do not have a polar group. • have an O atom, but there is no H attached. • cannot form hydrogen bonds between ether molecules. 28 Solubility of Alcohols and Ethers in Water Alcohols and ethers • are more soluble in water than alkanes because the oxygen atom can hydrogen bond with water. • with 1-4 C atoms are soluble, but not with 5 or more C atoms. Copyright © 2009 by Pearson Education, Inc. 29 Comparing Boiling Points and Solubility Copyright © 2009 by Pearson Education, Inc. 30 Chapter 12 Organic Compounds with Oxygen and Sulfur 12.3 Reactions of Alcohols and Thiols 31 Combustion of Alcohols Alcohols undergo combustion with O2 to produce CO2 and H2O. CH3—CH2—OH + 3O2 2CO2 + 3H2O + Energy 32 Dehydration of Alcohols Alcohols undergo • dehydration when heated with an acid catalyst. • the loss of —H and —OH from adjacent carbon atoms. H OH | | H+, heat H—C—C—H H—C=C—H + H2O | | | | H H H H alcohol alkene 33 Oxidation and Reduction In an oxidation, • there is an increase in the number of C-O bonds. • there is a loss of H. In a reduction, • there is a decrease in the number of C-O bonds. • there is a gain of H. 36 Oxidation and Reduction 37 Oxidation of Ethanol in the Body In the body, • enzymes in the liver oxidize ethanol. • the aldehyde produced impairs coordination. • blood alcohol over 0.4% can be fatal. O CH3CH2OH Ethyl alcohol CH3CH Acetaldehyde O CH3COH CO2 Acetic acid 38 Ethanol, CH3CH2OH Ethanol • acts as a depressant. • kills or disables more people than any other drug. • is metabolized at a rate of 12-15 mg/dL per hour by a social drinker. • is metabolized at a rate of 30 mg/dL per hour by an alcoholic. 39 Alcohol Contents in Common Products % Ethanol 50% 40% 15-25% 20% 12% 10% 3-9% Product Whiskey, rum, brandy Flavoring extracts ListerineTM, ScopeTM Formula 44DTM Wine, DristanTM NyquilTM, CepacolTM Beer, LavorisTM 41 Oxidation of Thiols When thiols undergo oxidation, • an H atom is lost from each of two –SH groups. • the product is a disulfide. [O] CH3─SH + HS─CH3 CH3─S─S─CH3 + H2O 42 Chapter 12 Organic Compounds with Oxygen and Sulfur 12.4 Aldehydes and Ketones 43 Carbonyl Group in Aldehydes and Ketones A carbonyl group • in an aldehyde is attached to at least one H atom. • in a ketone is attached to two carbon groups. 44 Naming Aldehydes An aldehyde • has an IUPAC name in which the -e in the alkane name is changed to –al. • has a common name for the first four aldehydes that use the prefixes: form (1C), acet (2C), propion (3C), and butyr (4C), followed by aldehyde. H C H Methanal (formaldehyde) O O O CH3 C H Ethanal (acetaldehyde) CH3CH2 C H Propanal (propionaldehyde) 45 •In a linear expression, the aldehyde group is often written as: CHO O C H3C H is equivalent to CH3CHO •In the linear expression of a ketone, the carbonyl group is written as: CO O C H3C CH3 is equivalent to CH3COCH3 Naming Aldehydes 48 Aldehydes in Flavorings Several naturally occurring aldehydes are used as flavorings for foods and fragrances. O C H Benzaldehyde (almonds) O CH CH C H Cinnamaldehyde (cinnamon) 49 Naming Ketones In naming ketones • in the IUPAC system, the -e in the alkane name is replaced with – one. • with a common name, the alkyl groups attached to the carbonyl group are named alphabetically, followed by ketone. O O CH3 C CH3 Propanone (dimethyl ketone) CH3 C CH2CH3 2-butanone (ethyl methyl ketone) 50 Ketones in Common Use Nail polish remover, solvent Propanone, dimethylketone, acetone Butter flavoring (Butanedione) 51 Aldehydes & Ketones in Nature 52 C C H O C C C C H O C OH C Violet (Irone) (Eucalyptus) O salicylaldehyde (meadowsweet) O C Piperonal (Heliotrope) O CH3(CH2)4C O H O CH3(CH2)10C (Citrus Fruits) H CH3 O O C C CH3 Raspberries 53 O C O H HO Benzaldehyde (Oil of Almonds) CH Oil of Cinnamon H CH3O Vanillin O CH C C H3C CH3 H CH3 O Camphor (Mothballs) 54 CH3 CH3 O C CHCH2CH2C CH C H CH3 Citral (Lemon Grass Oil) O O C C C C C C C C C (C)n C n = 4 or 6 CH3 Alarm Pheromones in ants 55 C C C Boll Weevil Sex Attractant C O H H C O H Citral (Honey Bee Recruiting Pheromone) 56 C (C)12 C C O C Musk Ox Sex Attractant (C)n C C O C (C)m m = 4, n = 10 m = 7, n = 7 m = 7, n = 9 Civet Cat Sex Attractant 57 Learning Check Name the following compounds: A. O CH3 CH2 CH2 C CH3 2-pentanone; methyl propyl ketone B. O CH3 CH3 C CH3 CH2 C H 3,3-dimethylbutanal 58 Learning Check Draw the structural formulas for each: A. 4-methylpentanal O CH3 CH3 CH CH2 B. 2,3-dichloropropanal Cl C. 3-methyl-2-butanone CH3 CH2 CH2 Cl O CH C CH3 O CH C C H H CH3 59 Chapter 12 Organic Compounds with Oxygen and Sulfur 12.5 Properties of Aldehydes and Ketones Hydrogen Bond Hydrogen Bond Acetaldehyde Acetone 60 Boiling Points Aldehydes and ketones have • polar carbonyl groups (C=O). + - C=O • attractions between polar groups. + - + - C=O C=O • higher boiling points than alkanes and ethers of similar mass. • lower boiling points than alcohols of similar mass. 61 Comparison of Boiling Points 62 Solubility in Water The electronegative O atom of the carbonyl group of aldehydes and ketones forms hydrogen bonds with water. Hydrogen Bond Hydrogen Bond Acetaldehyde Acetone 63 Tollens’ Silver Mirror Test In Tollens’ test, • Tollens’ reagent, which contains Ag+, oxidizes aldehydes, but not ketones. • Ag+ is reduced to metallic Ag, which appears as a “mirror” in the test tube. Ag+ + e– → Ag(s) 64 Benedict’s Test In Benedict’s test, • Benedict’s reagent, which contains Cu2+, reacts with aldehydes that have an adjacent OH group. • an aldehyde is oxidized to a carboxylic acid, while Cu2+ is reduced to give brick red Cu2O(s). 65 Increasing amounts of reducing sugar green orange red brown 66