Phase diagrams and decomposition for systems of (C 2H 5) 2NH·HCl C 6H 10 O 4 (adipic acid) and (C 2H 5) 2NH·HCl C 10 H 18 O 4 (sebacic acid) have been investigated by DTA, DSC and visual polythermal methods. Both two systems are of the simple eutectic type. Eutectics are located in 50% of C 6H 10 O 4 at 94 ℃ and 55% of C 10 H 18 O 4 at 106 ℃ respectively. (C 2H 5) 2NH·HCl melts at 217 ℃ and decomposes as soon as it just melted. A polymorphic reaction of (C 2H 5) 2NH·HCl occurs at 98 ℃, the transition heat is 29.7 J/g. Experiments also revealed that adipic acid melts at 152.8—155.7 ℃ with melting heat 199.1 J/g, decomposes at 250.8—263.0 ℃ with decomposition heat 174.2 J/g; sebacic acid melts at 133.1—135.9 ℃ with melting heat 199.8 J/g and decomposes at 233.2—269.2 ℃, but no exact value of decomposition heat has been determined. [WT5HZ]
