chapter 9

Chemistry 241 with Ngassa at Grand Valley State University

About this deck

By: Joe Mckeever
Textbook:

Organic Chemistry: Structure and Reactivity
Created: 2010-11-14
Size: 52 flashcards
Views: 48

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alcohol definition

compounds containing hydroxy group -OH

ethers definition

oxygen atom bonded to two carbon atoms

symmetrical ethers definition

an ether that has identical carbon groups

unsymmetrical ether definition

an ether that does not have identical carbon groups

epoxides definition

cyclic ethers in which oxygen is one atom of a three membered ring

alcohol PP (physical properties) polarity

more polar than alkanes of similar weights

alcohol PP bonding

can form H-bonds with H2O

alcohol PP solubility

more soluble in h2o than alkanes (like dissolves like)

alcohol PP boiling point

higher boiling point than alkanes of similar MW

alcohol PP B.P. trend

BP increases with increased MW

alcohol PP solubility within group

higher molecular weight alcohols are less soluble than lower MW alcohols

long hydrocarbon chain interferes with h2o molecules and prevents hydrogen bonding

alcohol prep alkyl halides

sn2 reactions using strong nucleophiles

alcohol prep from other functional groups

alkenes

aldehydes

ketones

carboxylic acid

esters

alcohol RXN acid-base

can act as acids or bases

alcohols as weak acids (w/ H20) compared to H2O

slightly weaker acids than H2O

alcohol as weak acids (w/ H20) carbon chain

acidity decreases with increase in carbon chain

alcohols as weak acids (w/ H20) electro-

acidity increases when electro- substituents are added to the carbon atoms near the hydroxyl group

inductive effect weakens H-O bonds

inductive effect decreases with distance away from O -->

the farther away an electro- substituent is away from the O, the less acidic

alcohols as weak bases (w/ H3O+)

when in an acidic content alcohols can act as a weak base

alcohols rxn with active metals which metals

Li, Na, K, Mg to form alkoxides and liberate H2 hydrogen gas

alkoxides

strong bases commonly used in organic reactions

alcohol substitution rxn from what to what?

alcohols form haloalkanes or alkyl sulfonates in sub. rxn

alcohol sub. rxn common reagents

HI, HCl, HBr, PBr3, SOCl2, RSO2Cl

alcohol sub. rxn LG

H20 because the H from the acid will react with the hydroxy group first then making a delicious LG and forming a carbo+ in which the electro- atom will react with

leaving group relevance

weak bases are better LG than strong bases

alcohol sub. rxn 1* mechanism

sn2

alcohol sub. rxn 2* mechanism

sn1

alcohol sub. rxn 3* mechanism

sn1

pyridine

forms a small amount of alkoxide (good nu:-) in solution

neutralizes HCl generated

alcohols to alkenes: dehydration type of catalyst

strong acid: H2SO4, H3PO4, TsOH

alcohols to alkenes: dehydration what type of rxn

elimination ---> Zaitsev's rule=the more stable alkene is the more substituted alkene 3*>2*>1*

oxidation

gain of O loss of H

reduction

gain of H loss of O

alcohol rxn oxidation: 1*

oxidized to aldehydes then to carboxylic acid

alcohol rxn oxidation: 2*

oxidized to ketones

alcohol rxn oxidation: 3*

no rxn because of lack of hydrogen atom on the carbon atom bearing the -OH group

jones reagent

oxidation

CrO3/H2SO4 in acetone

1* ---> C.A.

2* ---> ketone

chromic acid

oxidation

H2CrO4

1* ---> C.A.

2* ---> ketone

potassium dichromate in sulfuric acid

oxidation

K2Cr2O7/H2SO4/H2O

1* ---> C.A.

2* ---> ketone

pyridinium chlorochromate (PCC)

oxidation

CrO3/HCl/pyridine in CH2Cl2

1* ---> aldehydes

2* ---> ketones

periodic acids

oxidative cleavage

cleaves glycols to two carbonyl containing compounds

H5IO6, HIO4, 2H2O

MUST BE CIS AND MUST BE NEXT TO EACHOTHER

ether PP polarity

more polar than alkanes but less polar than alcohols

ether PP solubility

more soluble than alkanes but less soluble than alcohols

due to polarity and H-bonds

ether PP boiling point

boiling points are lower than comparable alcohols

---> can form h-bonds with H2O but not with each other

preparation of ethers Williamson Ether Synthesis

sn2 rxn between an alkyl halide and an alkoxxide ion in which the alkoxide ion displaces the halide ion

-just like sn2, doesn't occur with 3*

reactions with ethers reactivity

-used as solvents because generally unreactive-

only reaction is acid-catalyzed cleavage by concentrated HX

ether acid catalyzed cleavage by concentrated HX requirements

requires both a strong acid and a good nu:-

HI and HBr

ether acid catalyzed cleavage by concentrated HX products

haloalkane and an alcohol

ether acid catalyzed cleavage by concentrated HX excess

acid will kick out hydroxy group

R-O-R' + H-X(excess) --------> R-X + R'-X + H2O

ether acid catalyzed cleavage by concentrated HX normal

R-O-R' + H-X --------> R-X + R'-OH or R'-X + R-OH

when only 1* and 2* carbons are present (ethers)

cleavage will be sn2 like

when 3* carbon is present (ethers)

cleavage will be sn1 like

About this deck

By: Joe Mckeever
Textbook:

Organic Chemistry: Structure and Reactivity
Created: 2010-11-14
Size: 52 flashcards
Views: 48

About StudyBlue

“I have used this website for three exams, and I see a huge difference in my test results.”
Naj