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Aldehydes and Ketones Even more fun stuff! The Carbonyl Group Alds and Kets contain the carbonyl group-in carbohydrates, common in living things. • Carbohydrates are called polyhydroxyaldehydes/polyhydroxyketones • Naming alds and kets and diffs-see board – Include cyclic ketones – Weird ones alds/kets to know • • • • • Methanal-formaldehyde Ethanal-acetaldehyde Propanal-propionaldehyde Propanone-acetone-dimethyl ketone Butanone-methyl ethyl ketone (MEK) • *know both names and structures! Common aldehydes • Formaldehyde-the most common aldehyde • A gas at room temp • very toxic, denatures proteins, is immediately absorbed by the body • used to make plastics, adhesives (carpet) • Kills bacteria, sterilizes surgical instruments • Technically, not the exact stuff used in embalming Formalin • This is a 37% aqueous solution of formaldehyde • Is a biological preservative, used in embalming • Formalin reacts with proteins so that decay is inhibited and tissue becomes firmer • Funeral home story • http://www.youtube.com/watch?v=CBxu7fkhgt0 links for these 2 may not work • http://www.youtube.com/watch?v=vzhiKpmqvsA • Green burials http://videos.howstuffworks.com/planet-green/30105-gword-forever-fernwoods-green-burials-video.htm • Embalming school http://www.youtube.com/watch?v=SGSQ903qSAo&feature=fvw More alds • Acetaldehyde-toxic, but not as toxic as formaldehydecauses hangovers • Paraldehyde – once used as a hypnotic agent-not used much today b/c stinky and nasty tasting – Hypnosis videos http://videos.howstuffworks.com/discovery/31646-conspiracy-testrecalling-abductions-with-hypnosis-video.htm – http://videos.howstuffworks.com/sciencentral/2922-hypnoticsuggestion-video.htm – Show this one below-hypnosis in dentistry – http://www.youtube.com/watch?v=it_UfJ2by4k Common Ketones • alpha-chloroacetophenone • Structure • Alpha stuff • It’s a lachrymator-very stinky/irritating-is used in tear gas and Mace • Marines in gas chamber • http://www.youtube.com/watch?v=9Z5EQiNZ7I&feature=related • http://www.youtube.com/watch?v=obL3RPpCBM&feature=related Acetone • • • • good solvent, flammable, may cause cancer infinitely soluble in HOH Used to dry out wet lab glassware produced in the body during metabolism of lipids • Normally is metabolized, but not in diabetics • acetone can be excreted in urine and breath More diabetic stuff • When ketones in your body build upKetosis • If you have a very high level of ketones, you can go into a diabetic coma. • a high level of ketones can hurt the kidneys. Misc story-don’t write this • People have passed out on the street during diabetic comas. Police find them, smell acetone on their breath and throw them in jail thinking they were drunk. • Unfortunately, they sometimes die. Progesterone-a girl ketone • Norethynodrel-first oral contraceptive for womenmimics action of progesterone • Progesterone-hormone that preps uterine wall to accept fertilized egg • Depo Provera-injectable contraceptive works in 3 ways – prevents sperm from reaching egg – inhibits ovulation – makes uterine lining unfriendly to fertilized egg • *why some religions are opposed to the pill Testosterone-a boy ketone • Primary male sex hormone • Resp for 2ndy sex characteristics-what does that mean? • Also anabolic steroid • Girls have it also, but guys 40-60 x > More alds/kets • Dihydroxyacetone-in tanning lotions • Retinal-form of Vitamin A-too much can cause birth defects • other forms of vitamin A are retinol, retinoic acid • Capsaicin-gives red peppers their hotness-found in pepper spray • RTX (resiniferatoxin)-nose & skin irritant, used in sneezing powder • Both RTX and capsaicin have been used to treat bladder hyperreflexia-a need to go even when the bladder is empty Physical Props of Alds/Kets • Low Bpts b/c they don’t form H bonds w/each other-have no HO-’s! • They’re polar molecules b/c carbonyl group is polar-many are soluble in HOH • Have strong distinctive odors Prep of Aldehydes/Ketones • 1st degree alcohols aldehydesCA’s (like vinegar) • 2nd degree alcohols ketones • aldehydes go on to oxidize into CA’s but Ketones don’t oxidize • Aldehydes and kets can be changed back into alcohols by reduction (opp of oxidation) • Aldehydesreduced intoprimary alcohols • Ketonesreduced intosecondary alcohols Rxns of Alds/Kets • Alds must be kept in air-tight containers or else they will oxidize – Ethanolacetaldehydeacetic acid (vinegar) 99% of Ketones don’t oxidize(alpha hydroxy ones do) – **why is this significant??? B/c it allows us to have 2 common tests to tell them apart (alds from kets) 1. Benedict’s Test • Add unknown to the B’s solution (blue b/c of Cu in the Cu SO4 it contains), heat & look for a color change • Cu+2(blue) + 2 e-sCu0 (metallic, reddish-brown) • In the presence of an ald, the copper ion gains electrons-it is reduced! Charge decreases (chem I?) • The aldehyde(sugar) is oxidized • A color change from blue red is positive for ald • Kets give a neg test, no color change • Pregnancy test story 2. Tollens Test • • • • This is how they used to make mirrors Also called the silver mirror test Tollens solution contains AgNO3 unknown is added to the Tollens solution, heated, a silver precipitate is a positive test for an ald • http://www.youtube.com/watch?v=hUX_cp FWNso&feature=fvw
