how can i install Mac OS on toshiba intel celeron satellite L450-9P

No can do.

You can't. Mac OS only runs on Mac hardware. It is also not permitted by license agreement.

There are some folks who claim to have done it, but the results are not desirable.

But you can install Windows on a Mac via Bootcamp for dual boot.

But you can install Windows on a Mac via Bootcamp for dual boot.

For the purposes of Windows®, a Mac is just a generic piece of PC hardware, so installing on to it is permitted by Microsoft's EULA. On the other hand, Apple have explicitly stated in the EULA for OS X "Mountain Lion" that it should only be installed and run on Apple-branded hardware. Section 2, Paragraph B, Sub-section 1:

you are granted a limited, non-transferable, non-exclusive license […] to download, install, use and run for personal, non-commercial use, one (1) copy of the Apple Software directly on each Apple-branded computer…

(emphasis mine)

Section 2, Paragraph H:

The grants set forth in this License do not permit you to, and you agree not to, install, use or run the Apple Software on any non-Apple-branded computer, or to enable others to do so.

Also, discussion of how to run OS X on non-Apple branded hardware is against these forums' Use Agreement, Section 2 Paragraph 8, including Sub-section 1:

Keep within the Law

No material may be submitted that is intended to promote or commit an illegal act.

This thread'll be reported by someone if any salient advice is offered that enables the OP in his endeavour.