In an embodiment, a method of producing phosgene in a tube reactor comprises introducing a feed comprising carbon monoxide and chlorine to a tube of the reactor, the tube having a particulate catalyst disposed therein, wherein a thermally conductive material separate from the tube contacts at least a portion of the particulate catalyst; to produce a product composition comprising phosgene, and carbon tetrachloride in an amount of 0 to 10 ppm by volume based on the volume of the phosgene.