Synthesis of 2,6-dimethylpyrazine by dehydrocyclization of aqueous glycerol and 1,2-propanediamine over CuCrO catalyst: Rationalization of active sites by pyridine and formic acid adsorbed IR studies
Synthesis of 2,6-dimethylpyrazine by dehydrocyclization of aqueous glycerol and 1,2-propanediamine over CuCrO catalyst: Rationalization of active sites by pyridine and formic acid adsorbed IR studies
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DOI：
10.1016/j.apcatb.2016.04.018
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发表时间：
2016-09
影响因子：
22.1
通讯作者：
V. Krishna;G. Naresh;Vikas Kumar;R. Sarkari;A. H. Padmasri;A. Venugopal
中科院分区：
文献类型：
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作者：
V. Krishna;G. Naresh;Vikas Kumar;R. Sarkari;A. H. Padmasri;A. Venugopal
研究了不同Cu/Cr摩尔比的CuO单键CuCr_2 O_4（Cusingle bondCr single bondO）混合氧化物在甘油水溶液与1，2-丙二胺（1，2-PDA）反应合成2，6-二甲基吡嗪（2，6-DMP）中的应用。通过吡啶和甲酸吸附的漫反射红外傅里叶变换（DRIFT）光谱，合理化了酸碱（包括布朗斯台德和刘易斯）位置对产物分布的影响。吡啶吸附的DRIFT谱表明富铬（Cu 1 Cr 3）Cusingle键Cr单键O上的刘易斯酸中心数比富铜（Cu 2 Cr 1）Cusingle键Cr单键O上的多。甲酸吸附的红外光谱显示出强碱性位，归因于1584 cm− 1和1677 cm− 1处的振动带，这是由于甲酸物种在Cu 2Cr 1表面上的解离吸附。在甘油和1，2-PDA的脱氢环化反应中，建立了Cusingle键-Cr单键-O催化剂的Cu金属比表面积和酸碱强度与催化剂结构活性的关系。
The mixed oxides of CuOsingle bondCuCr2O4(Cusingle bondCrsingle bondO) with different Cu/Cr mole ratios were examined for synthesis of 2,6-dimethylpyrazine (2,6-DMP) by the utilization of aqueous glycerol in conjunction with 1,2-propanediamine (1,2-PDA). Influence of acid-base (both Bronsted and Lewis) sites on the product distribution is rationalized by pyridine and formic acid adsorbed Diffuse Reflectance Infrared Fourier Transform (DRIFT) spectroscopy. Pyridine adsorbed DRIFT spectra demonstrated relatively higher number Lewis acid sites on the chromium rich (Cu1Cr3) Cusingle bondCrsingle bondO than on copper rich (Cu2Cr1) Cusingle bondCrsingle bondO. The formic acid adsorbed IR spectra demonstrated strong basic sites attributed to the vibrational bands at 1584 cm−1and 1677 cm−1due to dissociative adsorption of formate species on Cu2Cr1surface. The structure activity relationship is established with Cu metal surface area and the acid-base strengths of the Cusingle bondCrsingle bondO catalysts in the dehydrocyclization of glycerol and 1,2-PDA.