Smart man's liquid nitrogen is dry ice mixed with 1,1-Difluoroethane. The boiling point of 1,1-difluoroethane is -11.29°F (-24.05°C) while it's
melting point is -178.6°F (-117°C). The sublimation point (the point at which a substance sublimes, or goes from a solid directly to a gas) of dry ice (solid carbon dioxide) is -109.2°F (-78.46°C). Smart man's liquid nitrogen stays at around -78°C as long as you keep supplying more dry ice. Then the dry ice runs out and it heats up until it reaches -25°C where it becomes
homeless man's liquid nitrogen. Then the 1,1-Difluroethane (can be found in computer duster) slowly boils away until it becomes gaseous 1,1-Difluoroethane. You can keep chemical reactions cool with smart man's liquid nitrogen and once it becomes
homeless man's liquid nitrogen, you can use a funnel and a plastic soda bottle to store the liquid difluoroethane under pressure and label it and put it in the lab freezer.
