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Synthesis and thermal decomposition mechanism of rare earth (RE=La, Y, Gd) salicylates
Author(s) -
Li LiangChao,
Zhou XiangChun,
Zheng RenWei
Publication year - 2004
Publication title -
chinese journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.28
H-Index - 41
eISSN - 1614-7065
pISSN - 1001-604X
DOI - 10.1002/cjoc.20040221113
Subject(s) - chemistry , thermal decomposition , dibenzofuran , monoclinic crystal system , decomposition , infrared spectroscopy , powder diffraction , evolved gas analysis , thermal analysis , elemental analysis , inorganic chemistry , crystal structure , crystallography , organic chemistry , thermal , physics , meteorology
The rare earth (RE=La, Y, Gd) salicylates were synthesized by the rheological phase reaction method. The complexes were characterized by elemental analysis, infrared spectra (IR), X‐ray powder diffraction (XRD) and thermal gravity analysis (TG). They can be represented by general formula RE(HSal) 3 (RE=La, Y, Gd; HSal= C 6 H 4 (OH)COO). The crystals of them are monoclinic and have layered structure. The mechanism of thermal decomposition of rare earth salicylates was studied by using TG, DTA, IR and gas chromatography‐mass spectrometry (GC‐MS). The thermal decomposition of the rare earth salicylates in nitrogen gas proceeded in three stages: firstly, they were decomposed to form RE 2 (Sal) 3 (Sal=C 6 H 4 OCOO) and salicylic acid; then, RE 2 (Sal) 3 were decomposed further to form RE 2 O(CO 3 ) 2 and some organic compounds; finally, RE 2 O(CO 3 ) 2 were decomposed to form rare earth metal oxides (RE 2 O 3 ) and carbon dioxide. The organic compounds obtained from the second step of the reaction are mainly dibenzofuran, xanthenone, 6 H ‐benzo[ c ]chromen‐6‐one, 6‐phenyl‐6 H ‐benzo[ c ]chromene, and 1,3‐diphenyl‐1, 3‐dihydro‐2‐benzofuran.