褐煤树脂中游离酸的化学组成与结构特征

CHEMICAL CONSTITUENTS AND STRUCTURAL CHARACTERISTIC OF FREE ACIDS IN BROWN COAL RESIN FROM CHINESE BROWN COAL WAXES

对云南潦浒、寻甸、吉林舒兰褐煤树脂中游离酸的化学组成及结构特征进行了对比研究。结果显示 ,潦浒和寻甸游离树脂酸主要是由去氢松香酸组成 ,其它三环二萜酸 ,如松脂酸、三达松脂酸、氢化松香酸、松香酸以及五环三萜酸均有分布 ,但含量低。正构烷酸C1 2 ～C2 8也存在着分布 ,且集中在C1 6、C1 8和C2 0 上。低碳数支链烷酸也被检出。因此 ,去氢松香酸是潦浒、寻甸游离树脂酸的特征代表物 ,与此相反 ,舒兰游离树脂酸则主要是由C1 2 ～C2 8正构烷酸构成 ,且集中到C1 6、C1 8和C2 0 上 ,其中C1 6含量最高 ,三环二萜及五环三萜酸等环状化合物不是该族组成的主要化合物。

The free acids, LHYLS, XDYLS and SLYLS, one of group fractions in brown coal resins in brown coal waxes extracted from Liaohu, Xundian (Yunnan province) and Shulan (Jilin province) brown coals respectively, were derived by CH2N2 to methyl ester and their chemical constituents and structural characterstics were studied on GC-MS The experimental results demonstrate that dehydroabietic acid (C20H30O2, MW302) is the dominant compound in both LHYLS and XDYLS Besides dehydroabietic acid, other tricyclic diterpanoic acids and pentacyclic triterpanoic acid, such as Pimaric acid, Isopimaric acid, sandaracopimaric acid, tetrahydroabietic acid, abietic acid and C32-hopanoic acid and C33-hopanoic acid, etc, are also existed in LHYLS and XDYLS A significant amount of fatty acids with normal long chain from C12 to C28 and branched fatty acids (low carbon number) are found in LHYLS and XDYLS, and the main compound among fatty acids is eicosanoic acid in LHYLS, hexadecanoic acid in XDLYS, but the total amount of fatty acids is much lower than cyclic compounds Therefore, dehydroabietic acid could be regarded as the characteristic compound of LHYLS and XDYLS Compared with TIC of LHYLS and XDYLS (methyl ester), the tricyclic diterpanoic and pentacyclic triterpanoic acids are not predominant in SLYLS It consists primarily of normal long chain and branched fatty acids from C12 to C28, with C16,C18,C20,C22 and C24 as major compounds. The order is C16>C18>C20>C22>C24 Benzoic acid, 3-methyl benzoic acid, 3,5-dimethyl benzoic acid and 4-ethyl benzoic aicd are also existed in SLYLS The chemical constituents suggest that the original resource of Liaohu brown coal wax would be similar to that of Xundian brown coal wax, but quite different from Shulan brown coal wax