2 added 32 characters in body edited Dec 22 '16 at 15:31 Nilay Ghosh 10.5k1010 gold badges4747 silver badges114114 bronze badges First, let's take a look at your proposed carbocation intermediate: $$\ce{Ph-O-CH2-CH2+}$$ This is a primary carbocation, which makes it very unstable. It's unlikely to form, so the reaction can't involve going through this stage. Primary halides are much more likely to undergo $$SN2$$$$\ce{S_N2}$$ or $$E2$$$$\ce{E2}$$ reactions. Whether it's the former or the latter will depend on the nucleophilic and basic charachter of the other reagent. Bases (specially if sterically hindered) tend to favor $$E2$$$$\ce{E2}$$, while nucleophiles of low basicity tend to favor $$SN2$$$$\ce{S_N2}$$. However, many reagents may and will give a mix of both products. With all this information, since $$KOH$$$$\ce{KOH}$$ is a very strong base and the reaction happens at high temperature, the result will be the $$E2$$$$\ce{E2}$$ product, in your second picture. First, let's take a look at your proposed carbocation intermediate: $$\ce{Ph-O-CH2-CH2+}$$ This is a primary carbocation, which makes it very unstable. It's unlikely to form, so the reaction can't involve going through this stage. Primary halides are much more likely to undergo $$SN2$$ or $$E2$$ reactions. Whether it's the former or the latter will depend on the nucleophilic and basic charachter of the other reagent. Bases (specially if sterically hindered) tend to favor $$E2$$, while nucleophiles of low basicity tend to favor $$SN2$$. However, many reagents may and will give a mix of both products. With all this information, since $$KOH$$ is a very strong base and the reaction happens at high temperature, the result will be the $$E2$$ product, in your second picture. First, let's take a look at your proposed carbocation intermediate: $$\ce{Ph-O-CH2-CH2+}$$ This is a primary carbocation, which makes it very unstable. It's unlikely to form, so the reaction can't involve going through this stage. Primary halides are much more likely to undergo $$\ce{S_N2}$$ or $$\ce{E2}$$ reactions. Whether it's the former or the latter will depend on the nucleophilic and basic charachter of the other reagent. Bases (specially if sterically hindered) tend to favor $$\ce{E2}$$, while nucleophiles of low basicity tend to favor $$\ce{S_N2}$$. However, many reagents may and will give a mix of both products. With all this information, since $$\ce{KOH}$$ is a very strong base and the reaction happens at high temperature, the result will be the $$\ce{E2}$$ product, in your second picture. 1 answered Dec 22 '16 at 15:13 Variax 87855 silver badges1515 bronze badges First, let's take a look at your proposed carbocation intermediate: $$\ce{Ph-O-CH2-CH2+}$$ This is a primary carbocation, which makes it very unstable. It's unlikely to form, so the reaction can't involve going through this stage. Primary halides are much more likely to undergo $$SN2$$ or $$E2$$ reactions. Whether it's the former or the latter will depend on the nucleophilic and basic charachter of the other reagent. Bases (specially if sterically hindered) tend to favor $$E2$$, while nucleophiles of low basicity tend to favor $$SN2$$. However, many reagents may and will give a mix of both products. With all this information, since $$KOH$$ is a very strong base and the reaction happens at high temperature, the result will be the $$E2$$ product, in your second picture.