I've been living in Germany for about 2 years and am now approaching fluency in the language. There is no such thing as "darohne", if you want to use it in a Nebensatz, as detraraveller said, it is ohne das, or whatever accusative article you need.
You of course can not use a da compound for any sort of Genetiv preposition:
wegen, deshalb, trotz, etc...
The same goes for "wo" compounds.
German, just like English has a lot of rules, which were made to be broken, so sometimes you just have to learn them and practice like mad! I'd really recommend investing in a good grammar book, especially if you are preparing for a language certificate. This book, helped me quite a bit though it might be really difficult to buy outside of the EU.