Alkanes – list of problems
(a) Draw and name all possible isomers of molecular formula C5H12.
(b) Identify the primary, secondary and tertiary hydrogens in each of the structures.
(c) Deduce which isomer forms a single compound in the monobromination reaction, without considering possible stereoisomers.
Draw the profile of the chlorination reaction via radical of methane, including the most likely transition state that would be observed in such a profile.
The halogenation reaction via radical of propane and 2-methylpropane gives the products and percentages indicated. Justify these experimental results and determine the relative reactivities of each type of hydrogen as a function of the halogen used.
In view of the results of problem 3, predict what proportion of products will be obtained in the monochlorination of 2,3-dimethylbutane.
Assuming that the order of reactivity of the hydrogens in the bromination reaction is:
- 3º 1600
- 2º 82
- 1º 1
predict the major product in the monobromination reaction of propane, butane, 2-methylpropane, cyclopentane and methylcyclopentane.
State the major product(s) of the monobromination of the following compounds:
Draw the constitutional isomers resulting from the monochlorination of 2,4-dimethylpentane, indicating which ones present chiral carbons.
Assuming that the chlorination reaction of methylpropane with an excess of chlorine leads to the formation of a dichlorinated derivative, draw all the possible constitutional isomers that would be obtained.
The bromination of pentane leads to the formation of three products one of which is a racemic form. Describe each of them and justify the result.
Assuming in the racemic mixture of the previous problem a second bromination occurs, draw the most probable structure of the products obtained, justifying the result.
Starting from (S)3-methylhexane, when the radical monobromination reaction is carried out, a reaction crude is obtained which is optically inactive. Justify the result obtained.
If cyclobutane reacts with more than one mole of bromine, how many dibromocyclobutanes would be obtained?
Draw the structures of the hydrocarbons (alkanes) that would be obtained in the pyrolysis of heptane.
What are the products of complete combustion of n-pentane? Adjust the reaction.
Adjust the complete combustion reaction of n-hexane.
Adjust the partial combustion reaction of isooctane (CH3 )3CC(CH3 )3.
Draw all the constitutional isomers (disregarding stereoisomers), obtained in the monochlorination of the following compounds:
Indicate in what proportion each of them would be formed taking into account the relative reactivities indicated in problem 3.
Draw all the constitutional isomers, disregarding stereoisomers, obtained in the monochlorination of the following compounds:
Identify the products obtained in the monochlorination of 2,4-dimethylpentane. Indicate whether any of these compounds have chiral carbons. If the rotational power of the reaction crude is determined, what would be the result?
Identify the products obtained in the dibromination of 2,4-dimethylpentane. Indicate if any of these compounds have chiral carbons.
Calculate the relative reactivity of the hydrogen atoms of butane in the chlorination reaction, knowing that monochlorination of this hydrocarbon yields 1-chlorobutane (28%) and 2-chlorobutane (72%).
Calculate the relative reactivity of the hydrogen atoms of 2-methylbutane in the chlorination reaction, knowing that monochlorination of this hydrocarbon leads to the formation of 1-chloro-2-methylbutane (27%), 2-chloro-2-methylbutane (23%), 2-chloro-3-methylbutane (36%) and 1-chloro-3-methylbutane (14%).
From the following relative reactivity data [ 1 : 1 : 4 : 6 ] of the following types of hydrogens [(CH3-)3 : (CH3-)2 : CH2– : CH- ], indicate the products obtained and the expected percentage in the monochlorination of 2,2,4-trimethylpentane.
Predict what will be the major product(s) of the monobromination reaction for the following alkanes:
Assuming you have to prepare a monobrominated derivative by a radical reaction, which hydrocarbons would you choose from the following list, and which would you discard?
The bromination reaction of both 2-methylbutane and (R)-3-methylhexane leads in both cases to a reaction crude that is optically inactive. Justify the result.
Starting from propane, pentane and 2,3-dimethylbutane, draw all the possible alkanes that can be formed by combination of the radicals obtained in a pyrolysis reaction.
Adjust the complete combustion reaction of n-butane.
Fit the partial combustion reaction (CO + H2O) of n-dodecane.