You can use File > Export as Catalog and the corresponding File > Import from Another Catalog.
However, 100k should not force you to fragment control of your workflow into separate catalogues. I routinely work on one that is over 5 times that size, and the only thing that's slower is backing up, which is done in non-working time. See http://kb2.adobe.com/cps/400/kb400808.html and above all, optimise your catalogue every so often.
AP Photo wrote:
Is there anyway I can move the old collections from an old catalog to the new catalog? Thanks for your reply.
Yes - here is one easy way:
Note: you can do publish collections too using this method (such is not the case via 'Import from Another Catalog').
PS - I recommend reading the documentation before embarking.