Oil from coal was proven viable (yet completely uneconomical) by the Germans in WWII, and much of their war machine was fueled by it. Sasol, the South African chemical giant, has been making oil from coal for many decades on a large scale. The problem is that the Fisher-Tropsch process of WWII fame has not been improved upon much at all, and it is still totally uneconomical. If Sasol did not have many other chemical success stories, and if it was not being subsidized heavily for its Fisher-Tropsch process of turning coal to oil, it would have gone bankrupt long ago.
Of course, there will come a time when natural oil will be so expensive that making it from coal (or wood, or natural gas, biomass, etc...) will become economical.