General principle of physics:

When using any vacuum drying solution (vacuum oven, rotary evaporator, freeze dryer ...) then the level of vacuum controls the boiling point of the solvent(s) and therefore the temperature of the sample, while it is still wet.  The available heat energy and rate of energy supply, drives the speed of evaporation, on the assumption that the vacuum pump (and cold trap / condenser) can remove the vapour produced at the same rate. 

Vacuum ovens are normally recommended for a solid product that is wet, e.g. wet sand.  Problem with using a liquid sample is that there is no control over which portion of your liquid will boil first, and when a big bubble tries to boil all at the same time, it will blast all over the inside of your oven.

A rotary evaporator can help prevent this by spinning the flask and making a thin film, but if you over fill the flask or pull the vacuum too fast the same thing can happen.  You can avoid this in a centrifugal evaporator (g force keeps the sample in the tube) or a freeze dryer where the sample is immobilised by freezing.

Could you adsorb the water on an excess of anhydrous sodium sulphate and centrifuge to remove?

Kind regards,

Rob

The First answer is really good. When I re-read again your question I understand that your problem is you have both impurities and water, from my own experence that is something normal. Is very likely that you will have to purify trough a cromatography procedure.

Another option is crystallize the product of the reaction, when i did solvent free synthesis I was able to obtain some compounds them in that way. It has the advantage that you quit some impurities of your final product and some humididty.

Good luck, i hope that you succeed.

By passing through the dessicants and by solar irrediations,