Powdered coke prevent the heat loss. As a result, it prevents burning of carbon electrodes.
The structure of tofacitinib with explicit carbon and hydrogen is the first attached picture.
The number of carbon atoms in tofacitinib are 16.
The molecular formula of tofacitinib is
.
The structure of tofacitinib with all the filled hydrogen atoms is the second attached picture.
They work by lowering the activation energy