物理化学学报 >> 2016, Vol. 32 >> Issue (9): 2327-2336.doi: 10.3866/PKU.WHXB201606225

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二氧化硅负载的不同碱金属硝酸盐催化乳酸缩合反应制备2, 3-戊二酮的催化性能比较研究

孙良伟,李新利*(),唐聪明*()   

  • 收稿日期:2016-04-12 发布日期:2016-09-08
  • 通讯作者: 李新利,唐聪明 E-mail:lixinlitcm@163.com;tcmtang2001@163.com
  • 基金资助:
    化学合成与污染控制四川省重点实验室科研开放基金(CSPC-2014-3-1);西华师范大学博士科研启动基金(12B019);四川省教育厅重点科研基金(16ZA0175)

Comparative Study on Catalytic Performance of the Production of 2, 3-Pentanedione from Lactic Acid Condensation over SiO2-Supported Alkali Metal Nitrates

Liang-Wei SUN,Xin-Li LI*(),Cong-Ming TANG*()   

  • Received:2016-04-12 Published:2016-09-08
  • Contact: Xin-Li LI,Cong-Ming TANG E-mail:lixinlitcm@163.com;tcmtang2001@163.com
  • Supported by:
    the Scientific Research Fund of Chemical Synthesis and Pollution Control Key Laboratory of Sichuan Province, China(CSPC-2014-3-1);Scientific Research Fund of China West Normal University, China(12B019);Scientific Research Fund of Sichuan Provincial Educational Department, China(16ZA0175)

摘要:

考察了二氧化硅负载的不同碱金属硝酸盐催化乳酸缩合制备2, 3-戊二酮的催化性能。在考察的碱金属硝酸盐如硝酸锂、硝酸钠、硝酸钾和硝酸铯作为催化剂的前驱体中,重点关注的是碱金属阳离子对乳酸缩合反应的影响。通过对这些硝酸盐前驱体在反应中的作用研究,发现硝酸铯的催化性能最佳。为了探究影响催化剂性能的原因,对新鲜催化剂和用过的催化剂采用X射线衍射(XRD)、傅里叶变换红外(FT-IR)光谱进行表征,发现所有的硝酸盐在反应过程中快速地转变为乳酸盐,并认为乳酸盐才是催化活性物种。随后,又借助CO2程序升温脱附(CO2-TPD)表征手段对用过的催化剂的碱性进行表征,发现二氧化硅负载的硝酸铯具有最强的碱性。乳酸缩合反应制备2, 3-戊二酮被广泛认为是碱催化反应,因此,二氧化硅负载的硝酸铯展示了最佳的催化性能。此外,本文还讨论了反应温度、硝酸盐的负载量等工艺条件对反应的影响。以4.4%(x,摩尔分数)CsNO3/SiO2为催化剂,在反应温度为300 ℃条件下,2, 3-戊二酮的收率达54.1%。

关键词: 乳酸, 2, 3-戊二酮, 缩合反应, 硝酸盐, 乳酸盐

Abstract:

The production of 2, 3-pentanedione from lactic acid over SiO2-supported alkali metal nitrates under various conditions was investigated. Using nitrate (NO3-) as the anion, the effect of alkali metal cations on Claisen condensation of lactic acid into 2, 3-pentanedione was focused on. Among precursors such as LiNO3, NaNO3, KNO3, and CsNO3, CsNO3 displayed the best catalytic performance. Characterization of the fresh and used catalysts by X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) spectroscopy revealed that all MNO3 (M=Li, Na, K, Cs) salts were transformed into alkali metal lactates during the reaction. Alkali metal lactates were identified as active species for catalytic Claisen condensation of lactic acid into 2, 3-pentanedione. CO2 temperature-programmed desorption (TPD) results of the used catalysts showed that the CsNO3/SiO2 catalyst was the most alkaline. For that reason, the CsNO3/SiO2 catalyst displayed the highest catalytic performance of those examined. The effects of reaction temperature and loading amount of CsNO3 on reaction performance were also discussed. Over the 4.4% (x, molar fraction) CsNO3/SiO2 catalyst, a 54.1% yield of 2, 3-pentanedione was achieved at 300 ℃.

Key words: Lactic acid, 2, 3-Pentanedione, Condensation, Alkali metal nitrate, Lactate

MSC2000: 

  • O643