difference between 化学工程 & 化学

Chemistry- you mostly do the discovery in the lab: synthesis of compounds, small molecule pharmaceutics, polymers, analysis of the above and their interaction with others. Basically chemistry is dealing with what's happening in a microworld at molecular level. CHemical company, pharmaceutical company, they need chemists.

Chemical engineering- dealing with synthesis at large scale, you have to consider a more different parameters such as: heating method, speed, time, vesicle shape and volume, fluid dynamics, tubing shapes and diameter,etc, mostly you know the experiment at bentch scale will happen, but need the chemical engineer to make it happen at large scale for commercial application. So big pharma, iol companies, they use a lot of chemical engineers.