...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Crystal growth & design >Kinetics of the Aqueous-Ethanol Solution Mediated Transformation between the Beta and Alpha Polymorphs of p-Aminobenzoic Acid
【24h】

Kinetics of the Aqueous-Ethanol Solution Mediated Transformation between the Beta and Alpha Polymorphs of p-Aminobenzoic Acid

机译：乙醇溶液的动力学介导的β和α-氨基苯甲酸的β和α多晶型物之间的转化

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

A quantitative kinetics analysis of the solution-mediated phase transformations in aqueous-ethanol between the enantiotropically related alpha and beta polymorphs of p -aminobenzoic acid (PABA) is presented. A new temperature-controlled transmission flow-cell design for use with a laboratory X-ray source which can be utilized for diffraction or scattering experiments is described. This transmission cell in combination with in situ slurry X-ray diffraction is utilized to provide a quantitative analysis of the percentage by mass of respective solid phases in flowing suspensions, coupled with solution concentration as measured with UV–vis spectroscopy. The separate phases are identified through individual fingerprint peaks, the (1 0 3) reflection at 2 θ = 15.6° relating to the alpha phase and the (0 2 2) reflection at 2 θ = 25.3° for the beta phase. Examination of the conversion of a slurry of beta PABA in a 70:30 water/ethanol solvent mixture to the alpha polymorph, at a temperature range of 24–30 °C reveals the rate of dissolution of the beta phase is consistent with zero order kinetics (rate constant k _(dβ) 6.80 × 10~(–4) to 8.17 × 10~(–5) wt % s~(–1)), while the growth of the alpha phase follows first order kinetics ( k _(gα) 1.00 × 10~(–3) to 2.50 × 10~(–4) wt % s~(–1)). Extrapolation of the growth and dissolution rate constants yields a transformation temperature for the phase interconversion of 22–24 °C. Overall the data are consistent with a fast de-supersaturation of the solution concentration indicating a dissolution-controlled polymorphic transformation process.
机译：介绍了对邻氨基苯甲酸（PABA）的脱色相关α和β多晶型不同乙醇中溶液介导的相变的定量动力学分析。描述了一种用于可以用于衍射或散射实验的实验室X射线源的新型温控传动流动单元设计。该传播电池与原位浆料X射线衍射组合用于在流动悬浮液中提供各自固相的质量百分比的定量分析，与用UV-Vis光谱测量的溶液浓度相结合。通过单独的指纹峰鉴定单独的相，（1 0 3）反射在2θ= 15.6°的反射与α相和（0 2 2）反射在2θ= 25.3°的β相。检查在70:30的水/乙醇溶剂混合物中βPABA浆料的转化为α多晶型物，在24-30℃的温度范围内显示β相的溶解速率与零级动力学一致（速率常数K _（Dβ）6.80×10〜（-4）至8.17×10〜（-5）wt％s〜（-1）），而α相的生长遵循一阶动力学（k _（ Gα）1.00×10〜（-3）至2.50×10〜（-4）wt％s〜（-1））。生长和溶出速率常数的外推得到22-24℃的相互连的转化温度。总体而言，数据与表明溶解控制的多态性转化过程的溶液浓度的快速去过饱和一致。

著录项

  • 来源
    《Crystal growth & design》 |2018年第2期|共9页
  • 作者

    Thomas D. Turner; Steve Caddick; Robert B. Hammond; Kevin J. Roberts; Xiaojun Lai;

  • 作者单位

    School of Chemical and Process Engineering University of Leeds Woodhouse Lane Leeds LS2 9JT U.K.;

    School of Chemical and Process Engineering University of Leeds Woodhouse Lane Leeds LS2 9JT U.K.;

    School of Chemical and Process Engineering University of Leeds Woodhouse Lane Leeds LS2 9JT U.K.;

    School of Chemical and Process Engineering University of Leeds Woodhouse Lane Leeds LS2 9JT U.K.;

    School of Chemical and Process Engineering University of Leeds Woodhouse Lane Leeds LS2 9JT U.K.;

  • 收录信息
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 晶体学;
  • 关键词

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号