多元醇固-固相变的变温红外光谱研究  

IR Spectra at Various Temperatures for Polyalchohols

作　　者：张建玲[1] 刘晓地[1] 何书美[2] 武克忠[1] 张建军[2] 冯海燕[1] 

机构地区：[1]河北师范大学化学系 [2]河北师范大学实验中心,石家庄050016

出　　处：《高等学校化学学报》2000年第6期937-940,共4页Chemical Journal of Chinese Universities

基　　金：河北省教育委员会专项科研基金项目 !(批准号 :97116)

摘　　要：利用变温红外光谱技术测定了 4种多元醇在 4 0 0 0～ 4 50 cm- 1 范围内的 IR光谱 ,分析了羟基的伸缩振动和面外变形振动随温度的变化情况 ,并结合 DSC对多元醇固 -固相变机理进行了探讨 .A set of series of polyalchohols derived from neopentane[C(CH 3) 4] by means of the substitution of —CH 3 by other groups such as —CH 2OH and —NH 2 exhibit crystalline transformations which reversibly absorb large amounts of heat and can be used in thermal energy storage. The solid solid phase transitions of pentylglycol(NPG), pentaglycerine(PG), pentarythritol(PE) and tris(hydroxymethyl)aminomethane(TAM) were studied by infrared spectroscopy at various temperatures and differential scanning analysis. Infrared spectra of four polyalchohols at room temperature show a strong absorption centered at 3 300 cm -1 which is identified as the —OH stretching band and indicate that between molecules there are hydrogen bonds which play a dominant role to the structure of low temperature phase(ordered phase). In the temperature range closely corresponding to the solid solid phase transition —OH stretching band shifts to a higher wavenumber, which indicate that the hydrogen bands between molecules are broken. The out of plane deformation of the OH group which is rather sensitive to molecular interactions was also analyzed. Its frequency deviation to lower wavenumber with the increase of the temperature also indicate that the hydrogen bands are broken. The enthalpies and temperatures of solid solid phase transitions for polyalchohols measured by DSC method are consistent with the results of IR which can declare the mechanism of solid solid phase transition of polyalchohols. With the breaking of hydrogen bonds between molecules and the introduction of vibrational and rotational disorder polyalchohols exhibt crystalline transition. The structure of the high temperature phase which are known as orientationally disordered crystals(ODIC) or plastic phase are face centered cubic for NPG, PG, PE and body centered cubic for TAM, which can be accounted for the difference between CH 2OH and NH 2 interactions. [WT5HZ]

关 键 词：多元醇 固-固相变 变温红外光谱 DSC法 热性质 

分 类 号：O623.413[理学—有机化学] O621.24[理学—化学]