Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
158 Cards in this Set
- Front
- Back
|
CH4
|
methane
|
|
|
CH3CH3
|
ethane
|
|
|
CH3CH2CH3
|
propane
|
|
|
CH3CH2CH2CH3
|
butane
|
|
|
11 carbon chain
|
undecane
|
|
|
12 carbon chain
|
dodecane
|
|
|
formula for a straight chain alkane
|
C(n)H(2n+2)
|
|
|
n-propyl
|
n = normal, or unbranched compound... so CH3CH2CH2 is the substitutent
|
|
|
t-butyl
|
C(CH3)3
|
|
|
neopentyl
|
CH2-C(CH3)3
|
|
|
isopropyl
|
CH(CH3)2
|
|
|
sec-butyl
|
CH(CH3)CH2CH3
|
|
|
isobutyl
|
CH2CH(CH3)2
|
|
|
alphabetizing substituents?
|
ignore di, tri, tetra, tert/t, sec, n; but cyclo-, iso-, and neo- are used
|
|
|
olefin
|
alkene (CC double bonds)
|
|
|
common name of ethene
|
ethylene
|
|
|
common name of propene
|
propylene
|
|
|
vinyl-
|
monosubstituted ethylenes
|
|
|
chloroethene
|
vinyl chloride
|
|
|
allyl-
|
propylene substituted at the C3 position (2-propenyl-)
|
|
|
3-bromo-1-propene
|
allyl bromide
|
|
|
methylene-
|
refers to -CH2, e.g. "methylene cyclohexane"
|
|
|
conjugated system
|
a carbon backbone with alternating single and double bonds; conjugation stabilizes through electron delocalization.
|
|
|
acetylene
|
ethyne
|
|
|
t-butyl bromide
|
2-bromo-2-methylpropane
|
|
|
2-iodopropane
|
isopropyl iodide
|
|
|
when there are both double and triple bonds?
|
y-root-en-x-yne" where y is position of the double bond and x is the position of the triple bond. Choose so that x+y is minimized and y is the smallest number possible; ex: 2-hexen-4-yne
|
|
|
alcohol or multiple bond when giving number priority?
|
alcohol
|
|
|
methyl alcohol
|
methanol
|
|
|
glycol
|
diols = molecules with 2 hydroxyl groups
|
|
|
vicinal
|
diols with hydroxyl groups on adjacent carbons
|
|
|
geminal
|
diols with hydroxyl groups on the same carbon
|
|
|
hydrates
|
geminal diols, not commonly observed because they spontaneously dehydrate to produce carbonyl compounds
|
|
|
ether
|
common name for diethyl ether
|
|
|
oxiranes
|
epoxides, or three-membered cyclic ethers
|
|
|
ethyl methyl ether
|
methoxyethane
|
|
|
name of the ether functionality..
|
alkoxy- (where alk = the smaller alkyl group)
|
|
|
ethylene oxide
|
oxirane
|
|
|
propylene oxide
|
2-methyloxirane
|
|
|
THF
|
tetrahydrofuran
|
|
|
methanal
|
formaldehyde
|
|
|
ethanal
|
acetaldeyhde
|
|
|
propanal
|
propionaldehyde
|
|
|
prefix for a substituent ketone
|
oxo-
|
|
|
acetone
|
2-propanone or dimethyl ketone
|
|
|
3-butene-2-one
|
methyl vinyl ketone
|
|
|
formic acid
|
methanoic acid
|
|
|
acetic acid
|
ethanoic acid
|
|
|
propionic acid
|
propanoic acid
|
|
|
ethanamine
|
CH3CH2NH2
|
|
|
ethylpentylamine
|
N-ethylpentanamine
|
|
|
IUPAC prefix/suffix for an ester
|
alkoxycarbonyl- / -oate
|
|
|
IUPAC prefix/suffix for an amide
|
(R-CONH2) amido- / -amide
|
|
|
IUPAC prefix/suffix for cyanide
|
(R-CN) cyano- / -nitrile
|
|
|
imine, general
|
R2 - C=NR'
|
|
|
sulfide, general
|
R2S
|
|
|
nitro, general
|
R-NO2
|
|
|
azide, general
|
R-N3
|
|
|
diazo, general
|
R-N2+
|
|
|
IUPAC prefix/sufix for a thiol
|
(RSH) sulfhydryl- / -thiol
|
|
|
isomers
|
compounds with same molecular formula but different structure - in atomic connectivity, rotational orientation, or the 3D position of the atoms
|
|
|
structural isomers
|
or constitutional isomers; only share the molecular formula. Since they differ in atomic connectivity, they may have very different chemical properties
|
|
|
stereoisomers
|
same connectivity, different orientation - includes diastereomers (geometric isomers), enantiomers, and conformational isomers.
|
|
|
geometric isomers
|
isomers that differ in the position of substituents attached to a double bond (cis, trans, Z, or E)
|
|
|
Z or E?
|
highest priority (determined by atomic #) on same side = Z (zusammen); opposite sides = E (entgegen)
|
|
|
chiral
|
an object that is not superimposable upon its mirror image, e.g. the left and right hands
|
|
|
enantiomers
|
chiral objects that are non-superimposable mirror images
|
|
|
R or S?
|
R = high to low priority is clockwise (rectus = right); S = counterclockwise (sinister = left)
|
|
|
orienation in a Fischer projection
|
horizontal lines project out, vertical point into the page
|
|
|
diastereomers
|
isomers that differ in their chirality but are not mirror images
|
|
|
meso compounds
|
contain chiral centers but are not optically active due to an internal mirror plan of symmetry
|
|
|
chemical properties of enantiomers?
|
are identical except for they rotate plane-polarized light in opposite directions
|
|
|
specific rotation
|
[alpha] = observed rotation(alpha) / concentration(g/mL) * length(dm)
|
|
|
a compound that rotates plane-polarized light to the right is called...
|
dextrorotatory or (+), vs. levorotatory (-)
|
|
|
racemic modification
|
or racemic mixture = a mixture of equal concentrations of both (+) and (-) enantiomers resulting in no optical activity
|
|
|
for n chiral centers, there are ____ possible stereoisomers
|
2^n
|
|
|
conformational isomers
|
compounds that differ only by rotation about one or more single bonds; can be depicted by Newman projection
|
|
|
straight-chain conformations
|
staggered or anti (lowest energy) -- eclipsed (methyl and hydrogen groups overlap) -- gauche (2 methyl groups are 60* apart) -- totally eclipsed (the two methyl groups overlap = highest energy)
|
|
|
cause of ring strain in cycloalkanes
|
angle strain (bond angles deveiate from ideal values), torsional strain (eclipsed interactions), and nonbonded strain or van der Waals repulsion (due to competition for same space)
|
|
|
envelope conformation"
|
cyclopentane
|
|
|
comformations of cyclohexane
|
chair, boat, and twist/skew-boat
|
|
|
conformation of cyclobutane
|
puckered (a "V" shape)
|
|
|
axial vs. equatorial position
|
perpendicular to the plan of the ring vs. parallel
|
|
|
boat vs. chair confomations
|
all atoms are eclipsed vs. all three types of strain are eliminated
|
|
|
bulky groups and ring conformation?
|
bulky groups prefer equatorial positions and can prevent chair "flipping"
|
|
|
trans in a chair conformation?
|
place substituents so that they point in opposite directions relative to the plan of the ring
|
|
|
a node (as related to orbitals)
|
an area where the probability of finding an electron is zero
|
|
|
number of nodes for a p vs. d orbital
|
1 and 2, respectively
|
|
|
energy of a bonding orbital?
|
lower than the molecular orbitals that add to make the bonding orbital
|
|
|
double bond consists of...
|
a sigma bond and a pi bond; with sp2 hybridization; the three sp2 orbitals are 120* apart
|
|
|
can a pi bond exist independently?
|
no, only after the formation of a sigma bond will the p orbitals of adjacent carbons be parallel; without the bond the three p orbitals are orthogonal to one another.
|
|
|
are pi or sigma bonds stronger?
|
sigma bonds are stronger
|
|
|
a triple bond consists of...
|
a sigma and two pi bonds; sp hybridized orbitals are 180* apart
|
|
|
alkanes
|
fully saturated hydrocarbons, consisting only of hydrogen and carbon atoms joined by single bonds
|
|
|
isobutane
|
HC(CH3)3
|
|
|
neopentane
|
C(CH3)4
|
|
|
as chain length of an alkane increases...
|
bp, mp, and density increase
|
|
|
at RT, straight-chain alkanes are in what state?
|
C1-4 are gases, C5-16 are liquids, and >16 are waxes and harder solids
|
|
|
increased branching in an alkane...
|
lowers bp (decreased surface area = decreased van der Waals) and density
|
|
|
symmetry and melting point?
|
the more symmetric molecule will have the higher mp (easier to pack into a tight, 3D structure)
|
|
|
free radical halogenation
|
initiation (homolytic cleagage of a diatomic halogen by heat or light) -- propagation (Xradical attacks RH to form XH and an alkyl radical, which attacks X2, regenerating the halogen radical) -- termination (two free radicals combine to form a stable molecule)
|
|
|
bromine and free radical halogenation?
|
Br radicals react fairly slowly and primarily attack the most substituted carbon atom
|
|
|
combustion
|
alkanes + O2 = carbon dioxide + water + heat
|
|
|
pyrolysis
|
also called cracking, most commonly used to reduce average MW of heavy oils and increase the production of the more desirable volatile compounds (C-C bonds are cleaved by heat and produce smaller-chain alkyl radicals that can recombine)
|
|
|
disproportionation
|
a radical transfers a hydrogen atom to another alkyl radical, producing an alkane and an alkene
|
|
|
nucleophiles and electrons
|
nucleophiles are electron rich (and thus are attracted to positively polarized atoms)
|
|
|
nucleophilicity and basicity
|
roughly correlated if the attacking atom is the same
|
|
|
nucleophilicity of oxygen-containing nucleophiles
|
RO- > HO- > RCO2- > ROH > H2O
|
|
|
solvent and nucleophilicity
|
large atoms are better in protic solvents (they can shed their solvent molecules and are more polarizable), but more basic compounds are better in aprotic solvents
|
|
|
nucleophile strength of halides
|
in an aprotic solvent, correlated to basicity: F- > Cl- > Br- > I- (the opposite is true in a protic or polar solvent)
|
|
|
size order of typical nucleophiles
|
CN- > I- > RO- > HO- > Br- > Cl- > F- > H2O
|
|
|
best leaving groups?
|
are the weak bases, because these can accpet an electron pai and dissociate to form a stable species (largest > smaller halides)
|
|
|
Sn1
|
unimolecular (rate is dependent on only one species... usually the formation of the carbocation or carbonium ion) nucleophilic substitution
|
|
|
solvents and carbocations
|
carbocations are stabilized by polar solvents that have lone electron pairs to donate (e.g. water, acetone)
|
|
|
increasing the rate of an SN1 rxn
|
in order to accelerate the formation of the carbocation consider 1) structural factors = more substitution means more charge delocalization; 2) solvent effects = polar protic solvents stabilize the intermediate and isolate ions; 3) nature of the leaving group = wk bases dissociate more easily
|
|
|
Sn2
|
bimolecular nucleophilic substitution
|
|
|
transition state of an SN2 rxn
|
Nu attacks the reactant from the backside to form a trigonal bipyramidal transition state
|
|
|
isobutylene
|
(CH3)2C=CH2
|
|
|
degree of unsaturation
|
number of double bonds or rings (for a compound CnHm), N = 1/2(2n +2 - m)
|
|
|
physical properties of alkenes vs. alkanes
|
alkenes show similar trends to alkanes - mp and bp increase with MW and are similar in value to the corresponding alkane
|
|
|
physical properties of trans vs. cis-alkenes
|
trans generally have higher mp (higher symmetry allows better packing in the solid state) and lower bp (less polar)
|
|
|
E1
|
unimolecular elimination, favored by highly polar solvents, highly branched carbon chains, good leaving froups, and weak nucleophiles in low concetration.
|
|
|
E1 and SN1
|
same factors favor both, so directing the rxn is difficult although high temperatures tend to favor E1
|
|
|
E2
|
bimolecular elimination; rate is dependent on the concentration of the substrate and the base
|
|
|
E2 mechanism
|
strong base (e.g. ethoxide ion) removes a proton while a halide ion anti to the proton leaves. If there are two possible products, the more substituted double bond is formed preferentially.
|
|
|
E2 vs SN2
|
steric hindrance does not greatly affect E2 rxns, and strong base favors E2 over SN2 (strong nucleophiles, or weak Lewis bases, favor SN2).
|
|
|
synthesis of an alkene
|
elminitation of either alcohol (with H+, heat) or alkyl halide (with base, heat) -- see E1 or E2
|
|
|
catalytic hydrogenation
|
the reductive process of adding molecular hydrogen to a double bond with the aid of a metal catalyst such as Pt, Pd, or Ni (usually Raney nickel, a special powdered form), but also Rh, In, or Ru; This is a syn addition.
|
|
|
syn addition
|
both atoms are added to the same face of the double bond
|
|
|
electrophilic additions
|
since the electrons of the pi bond are somewhat exposed, they are easily attacked by molecules that seek to accept an electron pair = Lewis acids or electrophiles
|
|
|
alkene + HX
|
proton accepts electrons of the double bond (acting as a Lewis base) to yield a carbocation which combines with the halide ion. This addition follows Markovnikov's rule b/c the initial protonation proceeds to produce the most stable carbocation.
|
|
|
Markovnikov's rule
|
the addition of something to the most substituted carbon in the double bond
|
|
|
alkene + X2
|
(a rapid process, often used to establish the presence of double bonds) Dbl bond acts as nucleophile and attacks an X2 molecule, displacing X- and forming a cyclic halonium ion. X- then attacks in a standard SN2 displacement - therefore the addition is anti
|
|
|
addition of X2 and the solvent
|
in a nucleophilic solvent, the solvent molecules can compete in the displacement step, producing different products (other than the dihalo compound).
|
|
|
alkene + H2O
|
only under acidic conditions!! Double bond is protonated according to Markovnikov's rule, carbocation formed, water attacks. Also performed at low temperature b/c the reverse reaction is an acid-catalyzed dehydration favored by high temp.
|
|
|
better way to add water to a double bond?
|
use mercuric acetate (Hg(CH3COO)2)
|
|
|
alternative mechanism to add HX to an alkene
|
through a free radical addition when there are peroxides, oxygen or other impurities present. The halide radical adds first to the double bond (so the addition is anti-Markovnikov). This rxn is useful for HBr but not HCl or HI.
|
|
|
presence of peroxides
|
think free radical reactions (that do not follow Markovnikov's rule)
|
|
|
hydroboration
|
diborane (B2H6) is a Lewis acid and attaches to the less sterically hindered C, followed by oxidation-hydrolysis with peroxide and aqueous base to produce an alcohol with overall anti-Markovnikov, syn orientation
|
|
|
potassium permanganate
|
KMnO4
|
|
|
oxidation of alkenes with potassium permanganate
|
if cold, dilute, aqueous KMnO4 used -- vicinal diols (glycols) with syn orientation produced + MnO2 (s); if a hot basic solution is used, followed by acid, then nonterminal alkenes are cleaved to form 2 molar equivalents of carboxylic acid and terminal alkenes ar ecleaved to form a carboxylic acid and CO2 (if the nonterminal double bonded carbon is disubstituted, a ketone is formed)
|
|
|
ozonolysis
|
1) alkene + O3, CH2Cl2, 2) reduction by zinc and water = cleavage of the double bond produces aldehydes -- or -- 2) reduction by soidum borohydride in methanol = cleavage of double bonds produces alcohols
|
|
|
sodium borohydride
|
NaBH4
|
|
|
examples of peroyxcarboxylic acids
|
peroxyacetic acid (CH3CO3H) and m-chloroperoxybenzoic acid (mcpba)
|
|
|
oxidation of alkenes by peroxycarboxylic acids
|
alkene + mcpba = oxirane or epoxide
|
|
|
polymerization of an alkene
|
ethylene + alkyl radical (R*), heat, high pressure = R-CH2-CH2-(CH2CH2)n-CH2CH2-R
|
|
|
methylacetylene
|
propyne (CH3CCH)
|
|
|
physical properties of alkynes
|
similar to analogous alkanes/alkenes; shorter-chains are generally gases that have higher bp than corresponding alkenes; have asymmetrical distribution of e- density = small dipole moments
|
|
|
effect of position of triple (double) bonds on physical properties
|
internal alkynes have higher bp than terminal alkynes; and terminal alkynes are fairly acidic with a pKa's around 25.
|
|
|
synthesis of an alkyne
|
1) elimination of 2HX from a geminal or vicinal dihalide, use heat and base -- or 2) convert a terminal triple bond into a nucleophile by removing the acidic proton with a strong base (e.g. n-BuLi), which can then perform nucleophilic displacements on alkyl halids at RT
|
|
|
Lindlar's catalyst
|
Pd on barium sulfate (BaSO4) with quinoline
|
|
|
reduction of alkynes to alkenes
|
1) H2, Lindlar's catalyst = cis-alkene -- or 2)sodium in liquid ammonia below -33* (Na, NH3) = trans-alkene via a free radical mechanism
|
|
|
boiling point of ammonia
|
is -33 degrees celsius
|
|
|
electrophilic addition to alkynes
|
occur according to Markovnikov's rule, use 1 equivalent of Br2 to stop at alkene stage
|
|
|
free radical addition to alkynes
|
anti-markovnikov orientation; product is usually the trans alkene isomer because the intermediate vinyl radical can isomerize to its more stable form
|
|
|
hydroboration of an alkyne
|
B adds first (can coordinate to three substrate molecules) in a syn mechanism; the B atom can be replaced with a proton from acetic acid to produce a cis alkene -- or a disubstituted borane (R2BH) can be used to prevent further boration of the vinylic intermediate which is then oxidatively cleaved with H2O2 to create an intermediate vinyl alcohol, which rearranges to the more stable carbonyl compound
|
|
|
aldehyde from an alkyne
|
(for a terminal alkyne) use R2BH, hydrogen peroxide, base -- produces a vinyl alcohol which can undergo keto-kenol tautomerism to form the aldehyde.
|
|
|
oxidation of alkynes
|
vis basic potassium permangenate (followed by acidification) -- or -- ozone, CCl4 (follow with water); both cleave the multiple bonds to produce carboxylic acids
|
