Chem220Midterm#2StudyGuide.pdf Chem 220
Popular in Organic Chemistry
Popular in Chemistry
This 12 page Study Guide was uploaded by Claira Notetaker on Sunday February 14, 2016. The Study Guide belongs to Chem 220 at University of Washington taught by Dr. Wiegand in Winter 2016. Since its upload, it has received 141 views. For similar materials see Organic Chemistry in Chemistry at University of Washington.
Reviews for Chem220Midterm#2StudyGuide.pdf
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 02/14/16
Chem 220 Midterm #2 Study Guide Chapter 14: Alcohols. Phenols, and Ethers Oxygen bonding • Can form either 2 single bonds or 1 double bond o Review: § Carbon forms 4 bonds § Hydrogen forms 1 bond § Oxygen forms 2 bonds Alcohols • Structural formula: R—OH o R = a carbon bonded to 3 other atoms (saturated carbon) o OH = hydroxyl group • Nomenclature (IUPAC) o Priority § Count the longest carbon chain that the hydroxyl group is attached to • Start the counting at the end closest to the hydroxyl group § Drop the ending (-e) and add (-ol) § Indicate the carbon number that the hydroxyl group is on § 2 hydroxyl groups • -diol § 3 hydroxyl groups • -triol § o In cyclo- shapes § The counting starts at the carbon hat is attached to the hydroxyl group • No need to put the number location in final name o As a substituent § Always takes priority over other substituent • Because of this it usually affects the ending and isn’t a substituent § Ending: -oxy o EX: § CH3—OH = methanol § CH3—CH2—CH2—CH2—OH = 1-butanol • Isomers o Constitutional isomers are possible for 3 carbon chain or more • Physical properties o Both polar and non polar § R group = non polar § OH = polar § Properties are determined by which group is dominate • Longer in length of carbon chain = more dominance • Multiple hydroxyl groups = dominance o Hydrogen bonding § Because of the OH group § Can bond to water molecules o Boiling point § High boiling point (higher than alkanes) • More carbons in chain increases boiling point • More hydroxyl groups increases boiling point o Solubility § Soluble in water • Because of the OH group § In carbon chain is more than 3 the solubility drops off dramatically because the R group is dominate • Classification of Alcohols o Primary (1 ) § Hydroxyl group is bonded to a carbon atom that is only bonded to one other carbon o Secondary (2 ) § Hydroxyl group is bonded at a carbon that is bonded to two other carbons o Tertiary (3 ) § Hydroxyl group is bonded to a carbon that is bonded to three other carbons o More R groups decreases the strength and ability of the OH group to perform hydrogen bonding • Chemical reactions o Combustion § R—OH > H2O + CO2 § O2 is required o Dehydration § Alcohol => Alkene + H2O § CH3—CH2—OH > CH2=CH2 + H2O § Needs heat (180 C) and H2SO4 to occur § This can happen in a ring structure too! § A form of elimination reaction • 2 groups or 2 atoms on neighboring carbon atoms are removed • This leaves multiple bonds between carbon atoms § This reaction is reversible • Hydration of an alkene = an alcohol o Zaitsev rule § The major product that is formed form the elimination reaction is the alkene that has the greatest number of alkyl groups attached to the carbon atoms of the double bond o Condensation § 1 Alcohol => ether + H2O • A hydrogen is removed from one reactant (removed from a bonded OH bond) • A hydroxyl group is removed from the other reactant • Water is formed from the new covalent bond § Need heat (140 C) and H2SO4 to occur o Oxidation and reduction § Oxidation: increase the number of C—O bonds and decreases the number of C—H bonds • —CH2—OH => C=O + H2O o The oxygen molecule is supplied form the oxidizing agent o The H2 is give from the alcohol • Primary alcohol o => Aldehyde => carboxylic acid • Secondary alcohol o => Ketone • Tertiary alcohol o => No reaction § Reduction: increases the number of C—H bonds and decreases the number of C—O bonds § The reaction will only occur with primary and secondary alcohols § A mild oxidation agent is needed for the reaction to occur • KMnO4 • K2Cr2O7 • H2CrO4 o Halogenation § 3R –OH + PX3 > 3R—X + H3PO3 • Heat is needed for the reaction to occur Phenols • Def: an aromatic compound with an –OH group attached to it o AR—OH • Nomenclature o Root: phenol o Start number carbons with the –OH group being on carbon #1 o Methyl derivatives of phenols are called cresols • Physical properties o Low melting solids or oily liquids are room temperature o Only slightly soluble in water (thanks to the –OH group) • Chemical properties o Flammable o Phenols cannot be dehydrated! o Readily oxidize (not in the same way as alcohols) o Undergoes halogenation § Hydroxyl group is replaced with a halogen atom o Acidity - + § Benzene ring—OH +H2O ó Benzene Ring –O + H3O • Phenol ó Phenoxide ion § Benzene ring –OH + NaOH => benzene ring –NaO + H2O • Phenol => sodium Phenoxide § Reaction undergoes in aqueous solutions and only produces small amount of products • Polyphenols o 2 or more phenol rings are present in a given compound Ethers • Def: organic compound that has an oxygen atom bonded to 2 carbon atoms by single bonds o -–C—O—C— § General formula: R—O—R ’ • R = alkyl group different from R • Nomenclature o Unsymmetrical ethers § Name both hydrocarbons bonded ot the oxygen in alphabetical order § Then just add the word ether at the end • EX: CH3—O—CH2—CH3 o Ethyl methyl ether o Symmetrical ethers § Name alkyl group add the prefix (di-) § Then add the word ether • EX: CH3—O—CH3 o Dimethyl ether o As substituent § Smaller hydrocarbon group attached to the –O is considered the substituent and the longer hydrocarbon chain is the root • Called a Alkoxy group (-OR) § Steps • Identify the longest hydrocarbon chain • The alkyl ending of the smaller carbon chain to –oxy o Indicate which carbon it is located on § EX: • CH3—O—CH2—CH2--CH2—CH3 o 1-methylocybutane • Benzene ring—O—CH3 o Methoxybenzene • Isomers o A lot of possibilities o Can be functional isomers with alcohols § EX: • CH3—CH3—CH3—OH o Propyl alcohol (C3H8O) • CH3—O—CH2—CH3 o Ethyl methyl ether (C3H8O) • Physical properties o Comparable boiling points to alkanes § Much lower than alcohols § Cannot hydrogen bond o Soluble in water § The oxygen can form a hydrogen bond with the water molecules • Chemical properties o Flammable o React slowly with air to form unstable hydroperoxides and peroxides § This is an explosion hazard! o Unreactive towards acids, bases, and oxidizing agents o Undergo combustion and halogenation • Cyclic ethers o Represents a heterocyclic organic compound § A compound din which one or more carbons in the ring is replaced with a different atom of another element Thiols • An organic compound where a oxygen atom is replaced by a sulfur atom o A sulfur analogy of an alcohol § R—SH • Nomenclature o Named the same way as alcohols except –ol becomes –thiol • Physical properties o Cannot form hydrogen bonds § Lower electronegativity o Lower boiling points than alcohols o Lower solubility than alcohols § But higher solubility than alkanes o Have a strong disagreeable odor • Chemical properties o Easily oxidized § R—SH + HS—R => R—S—S—R + 2H • 2 thiols => disulfide Thioethers (sulfide) • def: a sulfur atom bonded to 2 carbon atoms by single bonds o R—S—R • Nomenclature o Named the same way as ethers § Ether => sulfide § Alkoxy => alkylthio o EX: § CH3—S—CH3 • Dimethyl sulfide • Physical properties o Strong odor o Water soluble • Chemical properties o Flammable o More reactive than there alcohol and ether counter part • Isomers o Thiols and Thioethers are isomers as alcohol and ethers are isomers Chapter 15: Aldehydes and Ketones The carbonyl group • Carbon double bond to an oxygen o C=O § Both ketones and aldehydes contain a carbonyl group • The bond is a polar bond o Because of the oxygen molecule o A trigonal planar arrangement § Only 3 bonding groups because of the double bond Thiocarbonyl compounds • Sulfur containing carbonyl groups o Can replace the oxygen atom or the carbon atom • Very unstable and readily undergo decomposition Aldehydes • The carbon atom must be bonded to at least one hydrogen atom • Functional group o H o Other bond: § Hydrogen, alkyl group, or cyclo-alkyl group o Condensed form: § RCHO • Cannot form carbon ring structures • Nomenclature o Suffix –al o Steps § Select longest carbon chain that contains carbonyl group • Change ending to –al • The numbering of the parent chain starts so carbon#1 is the atom bonded to the oxygen molecule § Name substituents and on what carbon they are on • If the functional group is attached to a carbon chain, name the ring with –al suffix and then finish the word with –aldehyde • Oxidation o Aldehyde => carboxylic acid o Oxidation agent: KMnO 4 § Supplies the oxygen atom • Increases the number of C—O bonds o R H ó R OH o Tollen’s test § Causes a positive reaction if an aldehyde is present • Uses AgNO a3 NH 3 § Aldehyde => Carboxylic acid + silver metal o Benedicts test § Will detect an a+dehyde or a ketone with a positive reaction • Uses Cu § Aldehyde => carboxylic acid + brick-red solid • Reduction o Aldehyde => Primary Alcohol o o Ni, Pt, or Cu is the catalyst needed for the reaction to occur Ketones • Both of the additional bonds must be to a carbon atom • Functional group o R R o Condensed form § RCOR • Can form carbon ring structures • Nomenclature o Suffix –one o Steps § Select longest carbon chain that contains carbonyl group • Change ending to –one • The numbering of the parent chain starts so the carbonyl group has the lowest possible number § Name substituents and on what carbon they are on • Oxidation o No reaction! • Reduction o Ketone => Secondary alcohol o o Ni, Pt, or Cu is the catalyst needed for the reaction to occur Isomers for Aldehydes and ketones • Aldehydes and ketones have the same number of carbon atoms and same degrees of saturation o They can be functional isomers of each other Physical properties • Have a lower boiling point than alcohols o No hydrogen bonding occurs • Solubility o Have fewer than 6 carbons they are soluble in both water and organic solvents • Aldehydes o C1 and 2C are gas at room temp. o C3-C11 are liquid o C12< are solid • Ketones: generally have a pleasant odor • Aldehydes (low molecular mass) generally have pungent/unpleasant smell (high molecular mass) generally are more fragrant Reactions (aldehydes and ketones) with alcohols • Ketone or Aldehyde + Alcohol => Hemi-acetal + alcohol => acetal o Acid catalyst is needed for both steps o Hemi means half = half way to final product • Hemi-acetals formation o Formed from the addition of the carbonyl group (from aldehyde/ketone) and the molecule of alcohol § H (from Alcohol) + Carbonyl oxygen atom (from Aldehyde/ketone) § R—O (from alcohol) + Carbonyl carbon atom (from Aldehyde/ketone) § § o hemi-acetal must be bonded to § -OH group § -OR group o Found cyclic shapes in nature § The acyclic shape isn’t stable • Acetal Formation o Acetal must be bonded to § 2 –OR groups § • Acetal Hydrolysis o Acid catalyst is needed for reaction to occur o Acetal +H O2ó Aldehyde/ketone + R—OH + R —O—H 2 Chapter 16: Carboxylic acid, esters, and the derivatives Carboxylic acid • One of the 2 additional bonds must be attached to a hydroxyl group (-OH) • Functional group o OH o Condensed form § -COOH and -CO H 2 • Cant be in a cyclic shape Derivatives • Acyl group o Functional group § R § The carbon in the group is polar o All carboxylic acids and the derivatives must have this group. o Condensed structure § RCO- o Not that both ketones and aldehydes have this structure • General form • Z o Z = OR, Cl, NH ,2 Nomenclature • Steps o Select parent chain that contains the carboxylic group § Change the name ending to –oic § Number chain with carbon #1 as the carboxylic group o Identify and locate any substituents *if carboxyl group is bonded to a carbon ring, name the ring and then add “carboxylic acid” to the ending • Di carboxylic acid o Def” has 2 carboxyl groups at each end of the carbon chain § EX: • OH CH2—CH 2 OH o Butanedioic acid o Same naming but the ending is –dioic acid instead of –oic acid • Carboxylate ions o Produced from a hydrogen proton donation reaction o Mono carboxylic acids carry a (-1) charge o Di-carboxylic acids carry a (-2) charge o Naming, change –ic acid to –ate Physical properties • Most polar of the compounds we have learned about o Creates hydrogen bonds with water molecules § Aromatic carboxylic acids are generally not soluble in water! • Very high melting and boiling point o Strong intermolecular forces Chemical properties • Acidity o Is a proton donor because as it names implies it is an acid § R—COOH + H O =2 H O +3R—COO - § Carboxylic acid + water => Hydronium ions + Carboxylate ions o Considered a weak acid o Reaction with a strong base § Will produce a salt • Reaction can be reversed if salt is reacted with a strong acid § EX: - + • CH 3 OH + NaOH => CH 3 O Na + H 2 • Carboxylic acid + Strong base => carboxylic acid salt + water • Decarboxylation o Def: carboxylic acid is converted into a smaller molecule and carbon dioxide § Rest of molecule—CH 2 H => rest of molecule—CH + 3O 2 Esters • The one of the additional bonds must be a oxygen bond • Functional group o OR’ o it’s a carboxylic acid with the –OH becoming a –OR o from acid parent: R o from alcohol parent: --OR • Nomenclature o Acyl group: R o Alkyl group: -R o Steps § Name the alkyl group simple as you would any R group (this will be the first part of the name) § Then name the acryl group by dropping the -ic acid ending and adding –ate o EX: § CH 3 OH _ HO—CH => 3 3 O—CH 3 H O2 § Ethanoic acid + methyl alcohol => methyl acetate + water • Esterification o A condensation reaction o R OH + H—O—R ó R OR’ + H2O § Carboxylic acid + alcohol ó ester + water o Hydrogen ion are needed for this reaction to occur • Physical properties o Low boiling and melting point § Cant form hydrogen bonds (no hydrogen bonded to an oxygen) o Solubility § Low molecular mass ester are soluble in water • Chemical reactions o Hydrolysis, the opposite reaction of esterfication § Ester + water => carboxylic acid and an alcohol § R OR’ + H2O => R OH + H—O—R • The bond between the C and the single bonded O breaks § A strong acid catalyst is needed for the reaction to occur o Saponification § Def: a hydrolysis reaction under basic conditions, where a salt is one of the products § R OR’ + NaOH => R O Na + R’—OH § Ester + a strong base => a carboxylic salt + an alcohol § Water is needed for this reaction to occur Thio-esters • A sulfur containing ester o EX: § CH 3 S—CH —2H + H3 2 • Naming o Follow the same steps as you do for esters, just add a thio- in front of the word ester Acid chloride • General formula o R Cl • Naming o Change the –ic acid with –oyl chloride o Acid Anhydrides • General formula o R O R’ § Basically 2 acryl groups bonded togeterh with a singel oxygen atom • Naming o Symetrical (have the same R group) § Replace the acid aending with anhydride § EX: • CH 3 O CH 3 • Ethanoic anhydride o Unsymmetrical (different R groups) § CH —CH O CH 3 2 3 § ethanoic propanoic anyhdride Phosphoric acids • The carbon atoms that is in the carbonyl group is know replaced by a phosphorus atom • Reactions o A whole phosphate group can be transferred from one molecule from the next Acyl Transfer reactions • A compound containing a acyl group is reacted with an alcohol will for an ester and water o EX: o R OH + R’—OH => R O—R’ + H O 2 Free response problems 1. Nomenclature 2. Reactions (2 questions) a. Alcohols i. Dehydration 1. Heat is needed and temp of 180 C 2. Mechanism!! 3. Zaitsev rule a. Choosing where the double bond goes ii. Condensation 1. Heat is needed and a temp of 140 C 2. A primary alcohol iii. Oxidation 1. Know both the organic and inorganic products 2. Know the difference when it is primary, secondary, or tertiary alcohol; 3. An enzyme (NAD+) is needed for the reaction to occur iv. Halogenation v. Oxidation of Thiols 1. Disulfide reactions vi. Acid dissociation with phenols vii. Ether reacting with O2 b. Aldehydes and ketones i. Oxidation of aldehydes 1. Tollens and benedicts test ii. Reduction 1. NaBH4 or Ni +H2 is needed for the reaction to occur iii. Formation of hemi-acetals and acetals c. Chapter 16 i. Acid dissociation of carboxylic acid ii. Neutralization of acids and bases iii. Decarboxylation iv. Acyl transfer reaction v. Esterification 1. Mechanisms! vi. Acid hydrolysis 1. Mechanisms! 3. Isomers- stereoisomer a. Enanteomer: mirror image b. Distereomer: not mirror images 4. Mechanisms a. Alcohol dehydration, Esterification, acid hydrolysis of esters
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'