coal tar

plural coal tars

1. countableuncountableA black, viscous tar made by the destructive distillation of coal (to make coke and town gas); it contains a great number of compounds including hydrocarbons and phenols; used in the preparation of medicinal soap and shampoo, and industrially for the manufacture of many products.

   Phenol can be obtained from coal tars by two methods : (a) Directly by separation of the product contained in this type of feedstock, at the rate of 0.5 to 1.5 per cent weight.

   1989, Alain Chauvel, Gilles Lefebvre, Petrochemical Processes: Major Oxygenated, Chlorinated And Nitrated Derivatives, page 123

   1 more example

   Lewis Kirk, the inventor of the steam hammer, and John Dodsworth, of Reading, Penn. have invented a new compound which they say "experience has proved to be a superior compound for preventing friction. The invention is the union, under a high degree of heat, of oil with asphaltum, or with coal tar, or with both together.

   1847, editorial staff, “New Lubricating Compound”, in Scientific American, series 1, Volume 3, Issue 9, page 68