Do these sentences emphasize differrently ?
What do you emphasize, when :
- "Esst nicht im Bett,"
- "Nicht im Bett essen," ?
No, the emphasize is the same. The difference lies in the addressee and the tone. "Esst nicht im Bett!" is used informally towards a group of people. "Nicht im Bett essen!" is used like a rule or advise, it does not say to whom this is directed.
I hope I could be of help.
"Nicht im Bett essen" can also be a direct spoken order, not only a general rule (like those you would find on signs for example). But used orally it would sound quite annoyed and unfriendly without a "bitte".