I know the Nazis converted some of their ample coal reserves to fuel oil during WWII because of petroleum shortages, and the South Africans did the same during the embargo, so the technology not only exists, but has been around a long time. In the late 70s and early 80s I worked for an oil company that was working on coal-oil conversion schemes using government grant money, but they somehow could never get the process to work, in spite of a whole lot of money spent on a demonstration plant they constructed.

To be fair, perhaps the process is too expensive, or to polluting, to be competitive with petroleum, but no one seems to be talking about it.