Chapter 5- Alcohols and Alkyl Halides- Orgo 2 Exam

functional group

substituent that causes the molecules chemical reaction

functional groups

same _____ _______ will undergo similar chemical reactions regardless of composition

covalent

functional groups are a group of atoms with distinct chemical properties and are linked by _______ bonds

alkyl halides, haloalkanes, halogenoalkanes

group of chemical compounds derived from alkanes containing 1 or more halogens

degree of alkyl halides

alkyl halides are classified according to the carbon the halogen is attached - halogen is on primary carbon → primary alkyl halide

secondary alkyl halide

carbon that carries halogen is attached to two other carbons

tertiary alkyl halide

carbon that carries halogen is attached to three other carbons

halogen

whichever degree the carbon that holds the ______ is, it shares the same degree for the whole alkyl halide

fluoroalkane - alkyl fluoride

name of alkane with a fluorine attached to it

1) identify longest continuous chain of carbon (parent)

2) identify carbon with hydrogen

3) number chain utilizing lowest numbering system (no priority→ just make sure overall lowest number)

• use prefixes o → bromo, chloro, fluoro etc

nomenclature of alkyl halides

1) longest chain of carbons containing OH group → use alkane with the same number of carbons

2) chain numbered on the end nearest the OH group (OH takes priority)

3) number that contains the OH group is prefixed to the parent hydrocarbon and e is replaced with ol → pentane → pentanol

4) OH TAKES PRIORITY OVER OTHER GROUPS

nomenclature of alcohols

general formula of alcohol

CnH2n+1OH

general formula of alkyl halide

CnH2n+1X (where X is a halogen)

hydrohalogenation of alcohols

First way to make a alkyl halide

substituting OH of alcohol with the halogen of a H-X (halogen)

• OH and Br are (-) charged → anions → electron rich → making them nucleophiles

what is hydrohalogenation of alcohol

nucleophiles

electron rich species that forms covalent bonds by donating an electron pair

• negatively charged

• free pair of electrons or atleast 1 pi bond

lewis bases

nucleophiles are electron rich and donate electrons → making them ____ _____

electrophile

opposite of nucleophile

• positively charged or neutral with no lone pairs of electrons

• form bonds with nucleophile by accepting the lone pair from the nucleophile

lewis acids

electrophiles accept electrons → ____ _____

nucleophilic substitution

in hydrohalogenation of alcohols → one nucleophile (OH) is being substituted for another (Br) → ____ _____

positive, negative

the C-OH bond in alcohols is polar covalent, meaning the carbon is partially _____ and the OH is partially ____

electrophile, nucleophile

the hydrogen - halogen bond is polar covalent, where H is the _______, and the halogen is the __________

substrate

the substituent that is being acted upon in the reaction (starting compound) ie: the initial alcohol compound

leaving group

the nucleophile that is leaving and being substituted for ie: the OH

reaction mechanisim

step by step mechanism/sequence of elementary steps by which overall chemical change occurs

weak bases (Br-, I-, Cl- or H20)

good leaving groups are _______ _______ (stable on their own and low EN)

strong bases

bad leaving groups are ____ ______ (high EN)

weaker

the ______ the base, the better the leaving group

• Unimolecular

• 1st order

• 2 steps

• yes carbocation

• 3 and 2

SN1 reactions are

• __________ reaction

• ______ order kinetic mechanisim

• ____ steps

• yes or no carbocation

• which degree of alcohol reacts via SN1

• Bimolecular

• 2nd order

• 1 step

• no carbocation

• 1 and CH3

SN2 reactions are

• __________ reaction

• ______ order kinetic mechanisim

• ____ steps

• yes or no carbocation

• which degree of alcohol reacts via SN2

3 > 2 > 1 > > > CH3

carbocation stability

carbocation rearrangement

SN1 reactions can undergo _______ ________

hydride and alkyl shifts (FROM ADJACENT CARBON)

two types of carbocation rearrangements

minor and major products

through carbocation rearrangement _____ and ________ products are formed

carbocation

major product (more substituted) comes from the more stable ______, and minor (less substituted) comes from the less stable _______

endothermic (takes heat)

rate determining step is ______ in hydrohalogenation of alcohols

direct halogenation of alkanes or cycloalkanes

second way to form an alkyl halide

• high energy substitution

• 3 steps (initiation: requires UV) (propgation - uses one product from initation → continous) (termination is hard)

direct halogenation of alkanes

diatomic (2 molecules)

halogens are

homolytic clevage

bond break between diatomic halogens is called

chain (can be stopped using a high concentration of substituent compared to the halogen)

direct halogenation of alkanes is a form of a _____ reaction