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Hydrocarbon Derivatives

Hydrocarbon Derivatives. Aldehydes, Ketones, Carboxylic Acids, & Esters. Functional Group #4. Aldehydes. Carbonyl Group. >CO Oxygen attached to a carbon by a double covalent bond. Strong dipole. Al dehydes. O. General formula: R CH or RCHO

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Hydrocarbon Derivatives

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  1. Hydrocarbon Derivatives Aldehydes, Ketones, Carboxylic Acids, & Esters

  2. Functional Group #4 Aldehydes

  3. Carbonyl Group • >CO • Oxygen attached to a carbon by a double covalent bond. • Strong dipole

  4. Aldehydes O • General formula: RCH or RCHO • Carbonyl group is always at the end of the aldehyde (C on one side, H on the other). • Find the name of the alkane with the same # of carbons. Change the final e to -al. • Never need #’s for aldehydes – always at end. 

  5. O H = HCO H  HCH H Aldehyde comes from Alcohol Dehydrogenated

  6. HCH O  Methanal Common name = formaldehyde O H HCCH H  Ethanal = acetaldehyde 1 metabolic product of ethanol on its route to acetic acid.

  7. Acetaldehyde • Evidence that it is carcinogenic. • Natural component of many ripe fruits. • Contributes to odors of rosemary, daffodil, bitter orange, camphor, angelica, fennel, mustard, & peppermint. • A component of cigarette smoke.

  8. Ends in CHO so it’s an aldehyde. CH3CH2CH2CHO 4 Carbons so base name is butane. Drop final -e and add –al  butanal.

  9. Properties of Aldehydes - O R H H R - -  +  C=O C=O   + + H H Aldehydes are polar! Bumps up the boiling point. 1-way Hydrogen bonding in H2O. Bumps up solubility.

  10. Functional Group #5 Ketones

  11. Ketones • Carbonyl group , >C=O, located within a C chain instead of at the end. • General Format: R and R' may or may not be the same. O = RCR'

  12. Naming Ketones • Nearly always have a number. • Take the corresponding alkane name. • Drop final –e. • Add –one. • Number in front gives location of >C=O. (Lowest possible #.)

  13. H O H HCCCH H H = 2-propanone Common name = acetone O = CH3CH2CH2CCH3 2-pentanone

  14. Aldehydes & Ketones • Known for appealing tastes & smells. • Used as flavorings in food & candy. • Used as fragrances in perfumes. • Vanilla & cinnamon = aldehydes

  15. Properties of Aldehydes & Ketones • Aldehydes & ketones contain C=O group, which makes the molecules polar. • Boiling point: Higher than alkanes, lower than alcohols. • In pure aldehydes & ketones, hydrogen bonding does NOT occur. No H bonded to O. • Can have 1-way Hydrogen bonding in water, so they are pretty soluble in H2O.

  16. Functional Group #6 Carboxylic Acids

  17. Carboxylic Acids O Acidic H+ • General Formula = RCOH • Contains a carbonyl group & a hydroxyl group bonded to same C. • The H is acidic. It ionizes in water! • Carboxylic Acids are electrolytes! =

  18. Ionization of Acetic Acid CH3COOH + H2O  CH3COO- + H3O+

  19. Table R O = • General Format: R-C-OH or R-COOH

  20. Which of the following is an electrolyte? • CH3OH • CH3COOH • CH2O • C3H6O alcohol aldehyde ketone Correct answer is B, the carboxylic acid.

  21. Which of the following is a nonelectrolyte? • HCl • CH3COOH • NaOH • CH3OH Correct answer is D, an alcohol.

  22. Naming Carboxylic Acids • Never need a number – functional group always at end. • Find name of corresponding hydrocarbon. • Drop final –e. • Add the ending –oic + the word acid.

  23. O = HCOH 1 C  methane. Methanoic acid Sting in red ants, bees O H HCCOH H = Ethanoic Acid or Acetic acid 2 C  ethane

  24. CH3CH2CH2CH2COOH 5 C’s  pentane so the name is pentanoic acid.

  25. Common carboxylic acids • Acetic acid – vinegar. Also produced in doughs leavened with a specific yeast  sourdough bread • Citric acid • Tannic acid • Ascorbic acid • Lactic acid • Poly(lactic acid) – biodegradable polymers used as sutures in internal surgery.

  26. Properties of Carboxylic Acids • Contain –COOH group. • H is bonded to O. Hydrogen bonding occurs. Leads to increases in boiling point over corresponding alkane. • Also can form hydrogen bonds with water so the smaller acids are pretty soluble.

  27. Functional Group #7 Esters

  28. Esters O • General format: RCOR‘ • R and R‘ = hydrocarbon branches. Can be the same or different. • Esters contain a carbonyl group and a bridge O, both in the middle of the chain. • Esters are POLAR, but NO H bonded to O however. =

  29. Esters O = • RCOR‘ or RCOOR’ • Combination of a carboxylic acid & an alcohol. • The carbonyl group and “R” come from the carboxylic acid. • The bridging O and the R’ come from the alcohol.

  30. Esters • Responsible for many distinctive odors • Pineapple • Banana • Orange • Apple • Wintergreen

  31. Naming Esters • Name the hydrocarbon branch bonded to the bridge O first. Branches end in –yl. • The base name is derived from the branch containing the carbonyl group. Count up all the C atoms in this branch, including the C in the carbonyl. • Find the hydrocarbon base name. Drop the final –e and add –oate.

  32. O So you name this branch 1st. = CH3CH2COCH3 Carbonyl Group Bridge O Methyl Propanoate

  33. Bridge O O = CH3CH2CH2COCH2CH3 Name this branch 1st. Ethyl Butanoate Pineapple

  34. Bridge O O = CH3COCH2CH2CH2CH2CH3 Name this branch 1st. Pentyl Ethanoate Banana

  35. O = CH3OCCH2CH2CH3 Bridge O Name this branch 1st. 4 C’s on the other side = but Methyl butanoate - apple

  36. O = CH3CH2CH2CH2CH2CH2CH2CH2-O-C-CH3 Bridge O Name this branch 1st. 2 C’s on the other side: ethane Octyl Ethanoate orange

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