波谱分析教程_第2章_红外光谱(IR)改.ppt

解答 IUPAC Name: N-methylacetamide (N-methylethanamide) Analysis: C4H8O2 红外光谱技术的进展及其应用 红外显微镜(IR microscope) 漫反射傅立叶变换红外光谱技术（diffuse reflectance spectroscopy, DRS） 衰减全反射傅立叶变换红外光谱技术（attenuated total internal reflectance FTIR,ATR-FTIR） 光声光谱技术（photoacoustic spectoscopu, PAS） 红外联用技术：气相色谱/红外联用（GC/IR）技术、超临界流体色谱与红外光谱联用 图4-47 人毛发的截面图象 （a）可见图象 （b）3300 cm-1的NH伸缩振动红外成象 红外显微镜 全反射光路图（n1 光密物质 n2光疏物质 dp 光在光疏物质中入射深度） 光线在样品和棱镜间多次全反射 图中上层为样品，下层为棱镜 衰减全反射傅立叶变换红外光谱技术具有以下优点 不破坏样品，不需要对样品进行分离和制样，对样品的大小、形状没有特殊要求。 2）可测量含水和潮湿的样品。 3）检测灵敏度高，测量区域小，检测点可为数微米。 4）能得到测量位置物质分子的结构信息，某化合物或官能团空间分布的红外光谱图象及微区的可见显微图象。 5）能进行红外光谱数据库检索以及化学官能团辅助分析，以确定物质的 种类和性质。 6）操作简便、自动化，用计算机进行选点、定位、聚焦和测量。 红外定性分析 化合物的红外光谱鉴定 未知物化学结构的测定 红外光谱在宝石学上的应用 图 天然翡翠与B货翡翠的红外光谱图 I 天然翡翠 II B货翡翠 * Alcohols and amines display strong broad O-H and N-H stretching bands in the region 3400-3100 cm . The bands are broadened due to hydrogen bonding and a sharp non-bonded peak can often be seen at around 3400 cm . Alkene and alkyne C-H bonds display sharp stretching absorptions in the region 3100-3000 cm . The bands are of medium intensity and are often obscured by other absorbances in the region (i.e., OH). Triple bond stretching absorptions occur in the region 2400-2200 cm . Absorptions from nitriles are generally of medium intensity and are clearly defined. Alkynes absorb weakly in this region unless they are highly asymmetric; symmetrical alkynes do not show absorption bands. Carbonyl stretching bands occur in the region 1800-1700 cm . The bands are generally very strong and broad. Carbonyl compounds which are more reactive in nucleophilic addition reactions (acyl halides, esters) are generally at higher wave number than simple ketones and aldehydes, and amides are the lowest, absorbing in the region 1700-1650 cm . Carbon-carbon double bond stretching occurs in the region around 1650-1600 cm . The bands are generally sharp and of medium intensity. Aromatic compounds will typically display a series of sharp bands in this r