Govt Polytechnic Sonipat is affiliated by Haryana State Board of Technical Education. So you have to visit the official website of  Haryana State Board of Technical Education in order to get the syllabus.

To download the official syllabus for Diploma In chemical Engineering visit the link below:

http://hsbte.org.in/syllabi/study-scheme-and-curriculum-contents-for-2018-batch-onwards

or,

https://drive.google.com/file/d/1uG2SsL3FLqEUwP-zi-88g-12AAN8pcGC/view

I hope this answer helps. All the very best for your future endeavors!