KensyusyaのNew Japanese-English Dictionaryでは whileの接続用法は (1)−−−の間に、−−−と同時に While I was reading, I fell asleep. (2)−−とはいえ(although) While I admit his good points, I can see his bad. (3)−−ところが、一方(whereas, and) While I have no money to spend, you have nothing to spend money on.
whereasの接続用法は (主節と反対・対照の説を導いて)−−−のに、--ところが一方 例は、I hate, whereas you merely dislike him. One calls it politeness, whereas in fact it is nothing but weakness. というものでした。