OK, thank you.
An alternative to TEL is Methyl Tertiary Butyl Ether.
I have now idea if it will work. But I do not advise the use of tetraethyl lead, which is an extremely toxic substance.
Anyway the higher the temperature the greater the chance of side reactions.
I fail to see how MTBE can be an alternative to tetraethyl lead!!!!!
As I said
many times before you will get a mixture using these conditions.
Can you not utilize two starting materials and couple them?