How can a teacher who works from 1:0 PM to 5:0 PM uninterrupted maintain the Dhuhr and Asr prayers, what are the possible and preferred solutions, and is he considered sinful for delaying them?

A Muslim is required to observe prayer at its appointed time. Therefore, the questioner should ask the work administration to allocate time for prayer. If this is not possible, she should pray before the lecture after the time for prayer has begun, or inside the classroom. If even that is not possible, she should ask the administration to change the lecture time. If none of the above is possible, and the lecture extends over the times of Dhuhr and Asr prayers, and interrupting it would not lead to the loss of a legitimate benefit, then she may combine the two prayers by praying them early (jam' taqdeem) once Dhuhr time begins. If Dhuhr time has not yet begun, she should delay both prayers until the end of the working day and combine them by praying them late (jam' ta'kheer).