| 摘要 |
PROBLEM TO BE SOLVED: To obtain the subject colorant remarkably soluble in a refrigerant and a lubricant for an air conditioning system, having high compatibility with them and useful for leakage detection in refrigeration and air conditioning systems by adopting a naphthalimide derivative existing in a pure liquid state at an ambient temperature and an ambient pressure. SOLUTION: This colorant exists in a neat and liquid state at an ambient temperature (20-30 deg.C) and an ambient pressure (0.75-1.25 atm) and is pref. obtained by reacting a 4-halo-1,8-naphthalic anhydride with a branched alkylamine. N-hexyloxypropyl-4-hexyloxypropylamino-1,8-naphthalimide is exemplified as the colorant. It is pref. to introduce a mixture of the colorant with a lubricant into a refrigeration system containing a halogenated hydrocarbon and to actuate the system, followed by irradiating the system with ultraviolet rays and by detecting the fluorescence with the naked eye to detect leakage. |
