Relative Rates: Free-Radical Bromination

BroIn this experiment of the relative rates of free-radical chain bromination, we were evaluate to be adequate to(p) to determine the relative reactivates of the many types of total heat atoms involved toward bromine atoms. Bromination is delimit to be a regioselective reaction meaning bromine has preference of making or breaking a bond over all separate directions that it may have had available.In this case, Markovnikovs rule is revealed to be the case in this situation that states that adding a protic acid represented as HX to an alkene (sp2 hybridized), the hydrogen from that HX would be attracted to a carbon with the least alkyl groups and the halide (X) would become much attracted and give attach to the carbon containing more alkyl groups. Within the intermediate stage of the bromination reaction, the bromine radical will have already form and the electronegatively steeringd radical will have a choice of how to protonate in order to create a enduring carbocation.In or der to determine these sp3 hybridized carbons stability, it lot be determined by knowing that while comparing, if there atomic number 18 less alkyl groups attached to a carbocation, then there would not be enough electrons to slightly mask over the positive institutionalise on that certain carbocation. Due to this, the more alkyl groups that are attached, the more stable the carbocation would be due to the circumstance that the electron flow in the electron cloud slightly donates to the carbocation making it almost completely stable.During the experiment, we were anticipate to organize both groups of tubes with methylene chloride with their respective hydrocarbon (10 drops) as well as the addition of a small amount of bromine. One group of tubes was deposit in the light and one was set in the dark and when compa loss, you were already able to see that the ethylbenzene and toluene were the fastest to react in twain situations.Due to this fact we can tell since they were the f astest reacting, they can be associated with the fact that they were more than likely secondary and primary benzylic carbons due to their brilliant stability and fast reactions. The only other tube that reacted through watching (by eye) by the end of the experiment was the methylcyclohexane and we could tell that it had slightly reacted by its slight orange color, but was not still completely passing like the others(sign of bromine).The next most stable carbocation form would be the tertiary aliphatic carbon, so we will infer that this is what has occurred in this case. Due to the fact that methylcyclohexane is sp3 hybridized, we can pin point that our assumption that the bromination is tertiary aliphatic because it is stable with there being three alkyl groups present which means that the electrons within these groups are delocalized and are contained within an orbital that extends over the adjacent atoms involved. The stand firm two tubes to react within the group were cycloh exane and t-butylbenzene in that order.When first added the bromine, these two were the only ones that seemed to remain red longer and remained the same shade of red even after all of the other tubes had reacted. The reaction of cyclohexane however was expected to react slightly more than the t-butylbenzene due to the fact that the positive charge on the carbocation is delocalized better when there are more alkyl groups involved. This will match up the two with secondary (cyclohexane) and primary aliphatic (t-butylbenzene) bromination.