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Aldehydes Ketones Carboxylic Acids Esters. Hydrocarbon Derivatives. Carbonyl Group. >C O o xygen attached to carbon by double covalent bond s trong dipole-dipole forces. O. . Al dehydes. g eneral formula: R C H or RCHO c arbonyl group always at end of aldehyde
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Aldehydes Ketones Carboxylic Acids Esters Hydrocarbon Derivatives
Carbonyl Group • >CO • oxygen attached to carbon by double covalent bond • strong dipole-dipole forces
O Aldehydes • general formula: RCH or RCHO • carbonyl group alwaysat end of aldehyde • find name of alkane with same # of C’s • change the -e (in ane ending) to -al • never need #’s for aldehydes • functional group always on end C
O OH = HCH + H2 aldehydes created by dehydrogenating an alcohol HCH H
HCH O methanal O H HCCH H ethanal common name = acetaldehyde common name = formaldehyde
Acetaldehyde • carcinogenic compound • natural component of many ripe fruits • contributes to odors such as: • rosemary, daffodil, bitter orange, camphor, angelica, fennel, mustard, & peppermint • component of cigarette smoke
CH3CH2CH2CHO 4 carbons so base name is butane drop -eand addal butanal CHO ending indicates aldehyde
- O R H H R - - + C=O C=O + + H H Properties of Aldehydes aldehydes are polar! ↑ bp over alkane with same C’s H-bonding with H2O which ↑ solubility in water
O = RCR' Ketones • carbonyl group: >C=O • located onC in middle of chain instead of at end • general format: R and R‘: represent hydrocarbon chain - may or may not be the same
Naming Ketones • nearly always have number • take corresponding alkane name: • drop -e (from ane ending) & add -one • # gives location of functional group: >C=O • (lowest possible #)
H O H HCCCH H H = propanone common name = acetone = CH3CH2CH2CCH3 2-pentanone O
Aldehydes & Ketones • known for appealing tastes & smells • used as flavorings in food & candy • used as fragrances in perfumes • vanilla & cinnamon are aldehydes
Properties of Aldehydes & Ketones • aldehydes & ketones: • contain C=O group • molecules polar (soluble in water) • boiling point: • higher than alkanes (same # C’s) • lower than alcohols (same # C’s)
O Acidic H+ = Carboxylic Acids • general formula: RCOH • contains: carbonyl group AND hydroxyl group bonded to same C • H is acidic; so ionizes in water! • carboxylic acids are electrolytes!
Ionization of Acetic Acid CH3COOH(l) + H2O(l) CH3COO-1(aq)+ H3O+1(aq)
O = Carboxylic Acids • general format: R-C-OH or R-COOH
alcohol aldehyde ketone Which of the following is an electrolyte? • CH3OH • CH3COOH • CH2O • C3H6O correct answer is B (carboxylic acid)
Correct answer is D (alcohol) Which of the following is a non-electrolyte? • HCl • CH3COOH • NaOH • CH3OH
Naming Carboxylic Acids • never needs number: • functional group always at end • find name corresponding hydrocarbon • drop -e (from ane ending) & add -oic + acid
O 1 C methane methanoic acid sting from red ants, bees H HCCOH H = ethanoic acid acetic acid 2 C ethane = HCOH O
CH3CH2CH2CH2COOH 5 C’s pentane so the name ispentanoic acid
Common carboxylic acids • acetic acid – vinegar • produced in doughs leavened with specific yeast (ex: sourdough bread) • citric acid • tannic acid • ascorbic acid • lactic acid • produced in overworked muscles & causes pain • poly(lactic acid) – biodegradable polymers used as sutures in internal surgery
Properties of Carboxylic Acids • contain -COOH group • H bonded to O therefore hydrogen bonding • bp ↑ over corresponding alkane • form H bonds with water so smaller acids are very soluble in water
O = Esters • general format: RCOR‘ • R and R‘ = hydrocarbon branches • can be same or different • esters contain carbonyl group and an O bridge • both in middle of chain • esters are POLAR • no H-bonding
O = Esters • RCOR‘ or RCOOR’ combination of carboxylic acid & alcohol: • carbonyl group &“R” come from carboxylic acid • bridging O & R’ come from alcohol
Esters • responsible for many distinctive odors • pineapple • banana • orange • apple • wintergreen
Naming Esters • name hydrocarbon branch bonded to O bridge first • branches end in –yl • base name derived from branch containing carbonyl group • count up all C’s in this branch including the C in the carbonyl • find the hydrocarbon base name • drop the -e (from ane ending) & add -oate
O = CH3CH2C─O─CH3 bridge O methyl propanoate name this branch 1st carbonyl group
bridge O O = CH3CH2CH2COCH2CH3 name this branch 1st ethyl butanoate pineapple
bridge O O = CH3COCH2CH2CH2CH2CH3 name this branch 1st pentyl ethanoate banana
O = CH3OCCH2CH2CH3 bridge O name this branch 1st 4 C’s on the other side: but methyl butanoate apple
O = CH3CH2CH2CH2CH2CH2CH2CH2-O-C-CH3 bridge O name this branch 1st 2 C’s on the other side: eth octyl ethanoate orange