Is the azeotropic mixture of biphenyl and diphenyl ether liquid at room temperature? Is there any difference between hydrogenated terphenyl and biphenyl-diphenyl ether azeotrope as heat transfer oil?

Biphenyl-diphenyl ether should be the highest temperature heat transfer oil, which can be above 350 degrees. But it must be a proprietary heat transfer oil system, and the general system cannot be used. It is in gas phase when used and liquid at room temperature. Hydrogenated terphenyls's system is a liquid phase system, which is no different from the general heat transfer oil system, and its highest working temperature is between 330-350℃. I don't understand your process. There are more than two kinds of heat transfer oils. I guess the first one is that the reaction temperature can only be met by biphenyl system. Second, there may be a cooling process, and the cooling effects of the two oils are different. Biphenyl and hydrogenated terphenyls are gaseous and liquid when working, and cannot be mixed.