异构丁醇在四氯化碳、正庚烷、苯和1,2-二氯乙烷中的红外光谱研究

利用FT-IR,测定了四种异构丁醇十四氯化碳、 正庚烷, 苯和1,2-二氯乙烷稀溶液在3800—3000cm~(-1)内的红外吸收光谱。缔合峰与自由羟基峰的面积之比与溶质、溶剂的性质有关,且在极稀溶液区与溶质的质量百分比浓度之间有良好的直线关系。本文又运用1-n(环状)模型对有关体系进行了对比研究。结果表明,丁醇分子支链度的增加以及丁醇分子与苯和1,2-二氯乙烷之间的特殊相互作用,降低了醇分子的缔合能力。稀溶液中,丁醇分子在苯和1,2-二氯乙烷中主要以单体和环状二聚体形式存在,在四氯化碳中以单体和环状三聚体形式存在,而正丁醇分子在正庚烷中主要为单体和环状四聚体,异、仲、特丁醇主要为环状三聚体和单体。

INFRARED SPECTRA STUDIES OF BUTANOLS IN CARBON TETRACHLORIDE, n-HEPTANE, BENZENE AND 1,2-DICHLOROETHANE

The self-association of isomeric butanols in carbon tetrachloride, n-heptane, benzene and 1,2-dichloroethane has been studied by infrared sprectrometry in the range of 3800-3000cm~(-1). It has been found that the area ratios of polymer band to monomer band are related to the characteristics of the solutes and solvents, and the plots of the ratios against mass percent of the alcohol show good linear relation in the measured concentration range. The IR data have also been treated by use of 1-n (cyclic)association models. According to the results obtained,branched chain causes a decrease in some extent of the self-association. In addition, the specific interaction between isomeric butanols and benzene or 1,2-dichloroethane leads to much less selfassociation of butanols. In diluted solutions, butanol molecules mainly exist in the form of monomer-dimer in benzene and 1,2-dichloroethane, and of monomer-trimer in carbon tetrachloride. In heptane, however, the monomer-tetramer for n-butanol and the monomer-trimer for the other butanols may be the best models accounting for the IR data.