It's only possible to execute the chown command from the root user. Here is a very interesting reference post http://www.ale.org/pipermail/ale/200...er/099333.html
, but as it's quite long, I will post the part that is interesting for us.
The default with most OS's is for chown to be restricted to root only.
And there is a consensus that it should stay this way for security
considerations. If a non-root user does change the owner of a file and
any execute bit is on, the SUID and SGID bits must be cleared. This may
or may not happen with root.