Investigation of Hydrolysis in Poly（ethylene terephthalate） by FTIR-ATR

The hydrothermal aging of poly(ethylene terephthalate)(PET) was investigated at 70 95 °C. A new method to investigate the hydrolysis degree of PET by Fourier transform infrared spectroscopy(FTIR) was proposed. The spectra during the hydrothermal aging were measured using attenuated total reflection accessory(ATR). Peak resolving of carbonyl regions was performed, and the ratio of two groups of bands representing carboxylic acids and esters respectively were calculated to show the hydrolysis degree of ester groups in PET. The acid/ester ratio shows exactly the same trend as the average chain scission number per unit mass at various temperatures and thus can be used as a parameter to characterize the hydrolysis and random chain scission of PET. This method related to the hydrolysis mechanism directly, is simple, fast and convenient compared to the traditional methods such as viscometry, end-group titration and size exclusion chromatography(SEC). It may also be useful in hydrolysis characterization of other polyesters.     

Effect of Molecular Weight on the Properties of Poly（butylene succinate）

Poly（butylene succinate） （PBS） with different molecular weight was synthesized from 1, 4-butanediol and succinic acid by direct melt condensation. The synthesized PBS was identified by IH-NMR and FTIR spectrometry. The molecular weight was calculated from the intrinsic viscosity, and its value was between 20000 and 70000. The crystallization behavior and crystal morphology as function of molecular weight were investigated by DSC and PLM, respectively. The mechanical properties and hydrolytic degradation behaviors related with change of molecular weight were also studied in this work. The results demonstrated that the properties of PBS were determined by both molecular weight and crystallization properties （crystallinity as well as crystal morphology）. Our work is important for the design and preparation of PBS with proper molecular weight for its practical application.     

保护的二糖半乳吡喃糖基(α1→2)葡萄吡喃糖苷的合成

建立了一种新的保护的二糖半乳吡喃糖基(α1→2)葡萄吡喃糖苷的合成方法.甲基-4,6-O-苄叉基-β-D-葡萄吡喃糖苷(1)经区域选择性地苯甲酰化,得到受体甲基-3-O-苯甲酰基-4,6-O-苄叉基-β-D-葡萄吡喃糖苷(2).该受体与供体异丙基-2-O-苯甲酰基-3-O-烯丙基-4,6-O-苄叉基-β-D-1-硫代半...     

毛细管电泳分离-激光诱导荧光检测血清中的巴氯芬

首次将新合成的柱前衍生试剂6-氧-（N-琥珀酰亚胺乙酸酯）-9-（2′-甲氧羰基）荧光素（SAM F）用于巴氯芬（B aclofen）的衍生标记,并采用毛细管电泳分离-激光诱导荧光（CE-L IF）法分离检测衍生物。研究表明,在磷酸盐缓冲溶液（pH=7.5）介质中,30℃下10m in即可完成衍生反应。反应物在pH 5.6,35mm o.lL-1的磷酸盐缓冲溶液中12m in内达到分离,检出限为6×10-10m o.lL-1。本法用于血清中巴氯芬的分析测定,回收率为95.8%—101.0%。     

α-苯甲胺基-β-(3-吲哚基)-丙酸甲酯的合成

以L-色氨酸为原料经过4步得到α-苯甲胺基-β-(3-吲哚基)-丙酸甲酯,它是一种具有潜在的抗肿瘤活性的吲哚二酮哌嗪化合物的中间体,首先通过“酰氯法”合成L-色氨酸甲酯盐酸盐,再脱去盐酸,与苯甲醛发生缩合反应形成希夫碱,最后选择性还原,得目的产物,得率54.9%.     

牛磺酸Schiff碱及其Cu（Ⅱ）配合物的合成与表征

用牛磺酸与2-吡啶甲醛反应合成了一种牛磺酸Schiff碱,并制备了它与Cu（Ⅱ）的配合物[CuL（H2O）].NO3,其中HL=C8H10N2O3S,利用元素分析,红外光谱,紫外光谱,差热-热重分析及摩尔电导的测定等方法对Schiff碱及金属配合物进行了表征。     

铈(V)与左旋多巴的荧光反应及其分析应用

研究了左旋多巴与Ce(Ⅳ)在碱性体系中的荧光特性.实验发现,左旋多巴具有弱的内源性荧光,在pH为9.15的伯瑞坦-罗比森Britton-robinson(BR)缓冲介质中可与Ce(Ⅳ)发生反应,使其荧光强度显著增强,据此提出了测定左旋多巴含量的荧光分析新方法.左旋多巴含量在0.08-3.6μg/mL范围内与其荧光强度呈...     

混合表面活性剂-铬天青S与铜显色反应研究及应用

在曲拉通X-100(TritonX-100)和乳化剂(OP)存在下,基于Cu2+-铬天青S(CAS)的显色反应,建立了分光光度法测定微量铜的新方法.通过Cu2+与CAS-Triton X-100-OP形成灵敏度较高的多元配合物,来测量铜含量.络合物的最大吸收波长为618nm,表观摩尔吸光系数为ε=6.62×105L·m...     

紫草的提取工艺

对紫草提取工艺中各参数进行了优化,为紫草工业化提取提供一定的参考;以左旋紫草素含量的测定为工艺指标,通过正交设计试验,对乙醇浓度,乙醇体积,浸泡时间,及渗漉时间各因素进行了考察;紫草最佳提取工艺为：5倍量80%乙醇浸泡16h,再加10倍量80%的乙醇渗漉4h;适宜工艺为：5倍量80%乙醇浸泡12h,再加10倍量80%的乙醇渗漉4h;本工艺设计合理,工艺稳定,左旋紫草素提取率高,质量可控,适宜于工业化生产。     

流动注射分光光度法测定煤灰中的微量铀

在稀硝酸介质中,以2-(3-羧基苯偶氮)-7-(4-氯-2-膦酸基苯偶氮)-1,8-二羟基-3,6-萘二磺酸(CPA-mK)作为显色剂,建立了一种测定微量铀的流动注射分光光度法,在最佳实验条件下,该方法的线性范围为0-35mg/L,检出限为0.026mg/L,应用该方法测定煤灰样品中的铀,其相对标准偏差为1.8%-3....