English  |  正體中文  |  简体中文  |  Items with full text/Total items : 17776/20117 (88%)
Visitors : 11084920      Online Users : 614
RC Version 7.0 © Powered By DSPACE, MIT. Enhanced by NTU Library IR team.
Scope Tips:
  • please add "double quotation mark" for query phrases to get precise results
  • please goto advance search for comprehansive author search
  • Adv. Search
    HomeLoginUploadHelpAboutAdminister Goto mobile version
    Please use this identifier to cite or link to this item: http://ir.cnu.edu.tw/handle/310902800/28575


    標題: Extraction characteristics and kinetic studies of oleanolic and ursolic acids from Hedyotis diffusa under ultrasound-assisted extraction conditions
    作者: Wei, Ming-Chi
    Yang, Yu-Chiao
    貢獻者: 環境工程與科學系
    關鍵字: Hedyotis diffusa
    Oleanolic acid
    Ursolic acid
    Hyphenated procedure
    Ultrasound-assisted extraction
    日期: 2014-06
    上傳時間: 2015-05-06 21:21:14 (UTC+8)
    出版者: Elsevier Science Bv
    摘要: We report a hyphenated procedure for the extraction of oleanolic acid (OA) and ursolic acid (UA) from Hedyotis diffusa. The hyphenated ultrasound-assisted extraction (HUAE) procedure consists of heat-reflux extraction (HRE) followed by ultrasound-assisted extraction (UAE). This hyphenated technique uses a lower temperature, consumes less solvent and is faster than previous methods. Compared to heat-reflux and traditional ultrasound-assisted extractions, HUAE gave a 12% higher yield of OA and UA from H. diffuse and required less severe operating conditions. Thus, mild operating conditions can be used, which results in a higher quality product. HUAE is an effective and selective method for the extraction of OA and UA. Additionally, the HUAE of OA and UA from H. diffuse were interpreted using a second-order kinetic model to predict the extraction parameters at various temperatures. Furthermore, the activation energies for the extractions of OA and UA were 9.073 and 10.575 kJ/mol, respectively, based on the second-order extraction rate constants used to build the models. By fitting the main parameters of the model, we could compare the effects of the extraction parameters on the H. diffuse material and better understand the extraction process. (C) 2014 Elsevier B.V. All rights reserved.
    關聯: Separation and Purification Technology, v.130, pp.182-192
    Appears in Collections:[環境工程與科學系(所)] 期刊論文

    Files in This Item:

    File Description SizeFormat
    index.html0KbHTML694View/Open


    All items in CNU IR are protected by copyright, with all rights reserved.


    DSpace Software Copyright © 2002-2004  MIT &  Hewlett-Packard  /   Enhanced by   NTU Library IR team Copyright ©   - Feedback