Term
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Definition
| hydrocarbon that contains a C=C bond |
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Term
| the 2 most important organic chemicals produced industrially |
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Definition
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Term
| how ethylene, propylene, and butylene are synthesized |
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Definition
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Term
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Definition
| involves homolytic breaking of C-H and C-C bonds |
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Term
| thermal cracking reactions are dominated by... |
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Definition
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Term
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Definition
| describes the number of multiple bonds and/or rings in a molecule |
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Term
| how to calculate the degree of unsaturation of a compound |
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Definition
1: determine the equivalent hydrocarbon formula of the compound
2: add the number of halogens to the number of H's
3: subtract 1 H for every N
4: ignore the number of O's
5: calculate the number of paire of H's that would be present in an alkane that has the same number of C's as the equivalent hydrocarbon of the compound of interest. te difference is the degree of unsaturation. |
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Term
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Definition
| 1: find the longest chain containing the 2bl bond, and name it using "ene" as the suffix
2: number the C atoms in the chain, beginning at the end nearer the double bond
3: number the substituents and write the name
4: for cycloalkenes, the double bond is between C1 and C2, and substituents receive the lowest possible numbers
5: a -CH2- substituent is a methylene group, a H2C=CH- group is a vinyl group, and a H2C=CHCH2- group is an allyl group |
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Term
| the hybridization of VC atoms in a double bond |
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Definition
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Term
| the bonds formed in the 2bl bond between 2 C's |
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Definition
| 1 sigma bond and 1 pi bond |
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Term
| does free rotation occur around 2bl bonds? |
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Definition
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Term
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Definition
| disubstituted alkene that has substituents on the same side of the double bond |
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Term
| trans isomer of an alkene |
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Definition
| disubstituted alkene that has substituents on different sides of the double bond |
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Term
| do cis and trans isomers of alkenes interconvert? |
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Definition
| no because of the rigidity of the 2bl bond |
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Term
| when cis-trans isomerism in an alkene doesn't occur |
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Definition
| when one C in the 2bl bond is bonded to identical substituents |
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Term
| what the E, Z system of isomerism is used for |
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Definition
| it's used to describe the arrangement of substituents around a 2bl bond that can't be described by the cis/trans system |
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Term
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Definition
1: for each 2bl bonded C, rank its substituents by atomic number (kinda like you assign priorities in R and S configurations)
2: if a decision can't be reached based on the 1st atom, look at the 2nd or 3rd atom until a difference is found
3: multiple bonded atoms are equivalent to the same number of single bonded atoms |
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Term
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Definition
| has the higher ranked groups on the same side of the 2bl bond |
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Term
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Definition
| has the higher ranked groups on opposite sides of the double bond |
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Term
| which alkenes are more stable, cis or trans? |
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Definition
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Term
| why are trans alkenes more stable than cis alkenes? |
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Definition
| because cis alkenes have steric strain between the double bond substituents |
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Term
| stabilities of alkenes can be determined experimentally by measuring... |
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Definition
-cis-trans e'librium constants
-heats of hydrogenation |
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Term
| the most useful method for determining the stability of alkenes |
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Definition
| by measuring the heats of hydrogenation |
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Term
| heat of hydrogenation of a cis isomer vs that for a trans isomer |
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Definition
| the heat of hydrogenation of a cis isomer is a larger negative number thatn the heat of hydrogenation of a trans isomer |
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Term
| which alkene is of higher energy, cis or trans isomer? |
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Definition
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Term
| alkene 2bl bonds become more stable with... |
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Definition
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Term
| why alkene 2bl bonds become more stable with increasing substitution |
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Definition
| -hyperconjugation
-more substituted double bonds have more of the stronger sp2-sp3 bonds |
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Term
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Definition
| stabilizing interaction between the antibonding pi orbital of the C-C bond and a filled C-H sigma orbital oh an adjacent substituent |
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Term
| electrophilic addition reactions |
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Definition
| addition of an electrophile to a C=C bond to yield a saturated product |
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Term
| mechanism of the electrophilic addition of H-X to alkenes |
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Definition
| 1: the electrons of the nucleophilic pi bond attack the H atom of the electrophile H-X (X = Cl, Br, I, OH)
2: 2 electrons from the pi bond form a new sigma bond between -H and an alkene C
3: the carbocation intermediate reacts with X- to form a C-X bond |
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Term
| description of the energy diagram for the electrophilic addition of H-X to alkenes |
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Definition
-has 2 peaks separated by a valley (carbocation intermediate)
-the reaxtion is exothermic
-the first step is slower than the second step |
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Term
| Markovinikov's rule of orientation of addition reactions |
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Definition
-in the addition of HX to a double bond, H attaches to the C with fewer substituents and X attaches to the C with more substituents (regiospecific)
-if the C's have the same number of substituents, a mixture of products results |
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Term
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Definition
| describes a reaction that occurs with a specific regiochemistry to give a single product rather than a mixture of products |
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Term
| the structure of carbocations |
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Definition
| planar; the unoccupied p orbital extends above and below the plane containing the cation |
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Term
| the stability of carbocations increases with... |
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Definition
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Term
| carbocation stability can be measured by... |
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Definition
| studying gas phase dissociation enthalpies |
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Term
| carbocations can be stabilized by... |
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Definition
-inductive effects ofg neighhboring alkyl groups
-hyperconjugation |
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Term
| how a carbocation can be stabilized by hyperconjugation |
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Definition
| the mnore alkyl groups on the carbocation, the more opportunities there are for hyperconjugation |
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Term
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Definition
| postulate stating that we can get a picture of what a given transition state looks like by looking at the structure of the nearest stable species |
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Term
| exothermic reactions have transition states that resemble... |
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Definition
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Term
| endothermic reactions have transition states that resemble... |
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Definition
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Term
| why the transition state for an endothermic step resembles the product of that step |
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Definition
| because it is closer in energy |
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Term
| why the transition state for an exothermic step resembles the reactant of that step |
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Definition
| because it is closer in energy |
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Term
| in an electrophilic addition reaction, the transition state for alkene protonation resembles... |
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Definition
| the carbocation intermediate |
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Term
| more stable carbocations form faster because... |
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Definition
| their transition states are also stabilized |
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Term
| reactions in which products from carbocation rearrangements are formed |
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Definition
| some electrophilic addition reactions |
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Term
| the formation of products from carbocation rearrangements supports... |
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Definition
| the 2 step electrophilic addition mechanism, in which an intermediate carbocation is formed |
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Term
| how intermediate carbocations can rearrange to more stable carbocations |
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Definition
-a hydride shift
-an alkyl shift |
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Term
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Definition
| the shift of a H atom and its electron pair to a nearby cationic center |
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Term
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Definition
| the shift of an alkyl group with its electron pair to a nearby cationic center |
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