Oil from wood

the Wheeler process, has two stages:

Add sulfuric acid to wood. This is a very old pretreatment process that dissolves/breaks down lignin making cellulose available.

Heat the pulp with calcium hydroxide at 450 degrees Celsius, to remove oxygen.

This produces a hydrocarbon mixture similar to crude oil.

Distillation produces a petrol fraction with an octane of 80.

The acid and calcium hydroxide are recovered.  More..