Critical temperature of paraffin oil

Critical temperature (1) Definition or explanation: ① The temperature at which a substance is in a critical state. ②The highest temperature at which a substance exists in a liquid state. (2) Explanation: ① Each substance has a specific temperature at which, no matter how much the pressure is increased, the gaseous substance will not liquefy; this temperature is known as the critical temperature. Therefore, to liquefy the substance ； First, it is necessary to manage to reach its own critical temperature. Some substances such as ammonia and carbon dioxide have critical temperatures that are higher than or close to room temperature; such substances can be easily compressed into a liquid at normal temperatures. Some substances such as oxygen, nitrogen, hydrogen, helium, etc., have very low critical temperatures; the critical temperature of helium is -268. C. To liquefy these gases, appropriate cryogenic technology is necessary in order to reach their respective critical temperatures, after which pressure is increased to liquefy them. ②Gaseous substances at temperatures above the critical temperature are usually called gases, while those at temperatures below the critical temperature are called vapors. Critical temperature: The temperature at which a substance is in a critical state is called the “critical temperature”. Lowering temperature and increasing pressure are the conditions for liquefying a gas. However, applying pressure alone does not necessarily liquefy the gas; it depends on whether the gas is below its critical temperature at that time. If the gas temperature exceeds the critical temperature, the gaseous substance will not liquefy no matter how much the pressure is increased. For example, the critical temperature of water vapor is 374°C, which is much higher than normal temperatures; therefore, water vapor can easily be cooled into water under normal conditions. Others such as ether, ammonia, carbon dioxide, etc., have critical temperatures that are higher than or close to room temperature; such substances can be easily compressed into a liquid at normal temperatures. However, there are also some substances with very low critical temperatures; gases such as oxygen, air, hydrogen, and helium are all extremely difficult to liquefy. Among them, the critical temperature of helium is -268°C. To liquefy these gases. Certain cryogenic technologies and equipment are necessary to bring them below their respective critical temperatures, and then liquefaction is achieved by increasing the pressure. It seems that all of the above refer to pure substances. Wax oil is a mixture with a wide boiling range; to determine its critical temperature, isn’t it necessary to analyze its dry point and initial boiling point as well?