Orgo Prelim 3

General Formula for Alkyl Halides
R-X
where X=F, Cl, Br, I
(not a principal functional group)
General Formula for Alcohols
R-OH (*is a principal functional group. dictates name and gets lowest number when numbering the principal chain)
General Formula for Thiols
R-SH
(*also a principal functional group)
General Formula for Ethers
R-O-R’
(derivative, not a principal functional group)
General Formula for Sulfides (aka thioethers)
R-S-R’
(derivative, not a functional group)
In hydrogen bonding, what are the most important donors
acids, alcohols, amides
in hydrogen bonding, what are the most important acceptors
aldehydes, ethers, amines, alkyl fluorides
What are the three different properties to consider when choosing a solvent
Bronsted properties, Lewis properties, Polar properties
What are examples of polar aprotic solvents?
DMSO, DMF, compounds that have good + stabilization but no – stabilization
What are examples of polar protic solvents?
H2O, alcohols, excellent + / – stabilization
What examples of nonpolar protic solvents?
acetic acid, CH3COO
Name examples of aprotic polar solvents that are donors
THF, diethyl ether, dioxane
Name examples of aprotic polar solvents that are nondonors
hexane, benzene, CH2Cl2
What kinds of solvents have good (+) / (-) stabilization?
polar protic solvents, nonpolar protic solvents,
Which solvents have good (+) stabilization but no (-) stabilization?
polar aprotic and nonpolar aprotic solvents
What inluences acidity?

  • periodic trends
  • element effect
  • resonance
  • polar effect
  • solvation

How does solvation influence alcohol acidity

  • salvation stabilizes A and increases acidity

A-H —> A + H+

  • the higher the pKa value the weaker the acidity

 

How are alkyl halides classified

as methyl, secondary, or tertiary, depending on the number of alkyl groups attached to the carbon bearing the halogen

 

methyl-no alkyl groups

primary-one

secondary-two

tertiary-three

in an alcohol, where is the hydroxy (OH) group bonded to
bonded to the carbond of the alkyl group. also classified as methyl, primary, secondary, or tertiary.
what are glyols
compounds that contain two or more hydroxy groups on adjacent carbons
what does it mean to be a “polar” molecule

has a permanent dipole moment

ex: methyl chloride, methanol, diethyl ether, propane

what is the relationship between polarity and boiling points
as polarity increases, the boiling point also increases.
what is true about molecular masses and boiling points

even though two compounds may have similar molecular masses, their BPs might be different because they have different molecular shapes and sizes.

 

large intermolecular attractions translate into high BPs so alkanes have higher BPs than alkyl halides

what are three ways dissolved ions are stabilized
charge-dipole interactions, hydrogen-bonding interactions, donor interactions
what is an amphoteric substance (also give example)

a substance that can either lose or gain a proton.

 

ex: alcohols and thiols

how does the gain or loss of a proton affect acidity/basicity

the acidity of an alcohol is the loss of a proton

 

the basicity of an alcohol is the gain of a proton

organometallic compounds

compounds that contain carbon-metal bonds

 

ex: oxymercuration and organoboranes

grignard reagent

a compound of the form R-Mg-X

X= Br, Cl, I

 

ex: ethylmagnesium bromide

CH3CH2-Mg-Br

Organolithium reagents

compounds in the form R-Li

 

ex: butyllithium

CH3CH2CH2CH2-Li

How are Grignard and organolithium reagents formed?

using ether solvents to add an alkyl halide to a metal

 

CH3CH3-Br + Mg ———–> CH3CH2-Mg-Br

(C2H5)2O

Why aren’t solvents required for the formation of organolithium reagents

they are soluble in hydrocarbons.

;

Grignard and organolithium reagents react violently with oxygen and vigorously with water

What are carbanions and which compounds react as if they were carbanions

Carbanions are carbons bearing three bonds, an unshared pair of electrons, and a negative formal charge.

;

Grignard and organolithium reagents react as if they were carbanions:

R3-C-MgX —-> R3C:–     MgX+

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