Luna Juan, Alcoutlabi Mataz, Fletes Elizabeth, Morales Helia, Parsons Jason G
School of Integrative Biological and Chemical Sciences, University of Texas Rio Grande Valley, 1 West University Blvd, Brownsville, TX 78521, USA.
Department of Mechanical Engineering, University of Texas Rio Grande Valley, 1201 W University Drive, Edinburg, TX 78539, USA.
Molecules. 2025 May 6;30(9):2065. doi: 10.3390/molecules30092065.
In this study, a vanadyl phthalocyanine was synthesized and characterized using XRD, FTIR, and XPS, confirming the successful metalation of the phthalocyanine ring. XRD analysis showed the vanadyl phthalocyanine crystallized in the P-1 crystal lattice, with unit cell parameters a = 12.058 Å, b = 12.598 Å, and c = 8.719 Å, and the lattice angels were 96.203°, 94.941°, and 68.204°. FTIR spectroscopy supported the metalation by the disappearance of the N-H stretch of the non-metalated phthalocyanine. The vanadyl phthalocyanine was tested as a heterogenous catalyst for the conversion of fructose into methyl levulinate in HSO-methanol and HCl-methanol systems. The HSO-methanol reaction system catalyzed with the vanadyl phthalocyanine, and a zeroth-order rate constant of 1.10 × 10 M/s was observed, which was 1.74 times faster than sulfuric acid alone. The HCl-methanol system showed a zeroth-order of reaction with a rate constant of 2.33 × 10 M/s, which was 1.3 times faster than the HCl-methanol alone. While the HCl-methanol system showed a faster reaction rate, product distribution favored methyl levulinate formation in the HSO-methanol system. The main products identified were methyl levulinate and hepta-2,4-dienoic acid methyl ester, with a minor amount of hydroxymethylfurfural formed. These results suggest that vanadyl phthalocyanine can be effectively used as a catalyst to increase the rate of fructose conversion to methyl levulinate in either HSO or HCl-methanol.
在本研究中，合成了一种钒氧基酞菁，并通过X射线衍射（XRD）、傅里叶变换红外光谱（FTIR）和X射线光电子能谱（XPS）对其进行了表征，证实了酞菁环金属化成功。XRD分析表明，钒氧基酞菁在P-1晶格中结晶，晶胞参数a = 12.058 Å，b = 12.598 Å，c = 8.719 Å，晶格角分别为96.203°、94.941°和68.204°。FTIR光谱通过未金属化酞菁的N-H伸缩振动消失来支持金属化。在HSO-甲醇和HCl-甲醇体系中，对钒氧基酞菁作为果糖转化为乙酰丙酸甲酯的多相催化剂进行了测试。钒氧基酞菁催化的HSO-甲醇反应体系，观察到零级速率常数为1.10×10 M/s，比单独使用硫酸快1.74倍。HCl-甲醇体系显示出零级反应，速率常数为2.33×10 M/s，比单独的HCl-甲醇快1.3倍。虽然HCl-甲醇体系显示出更快的反应速率，但在HSO-甲醇体系中产物分布有利于乙酰丙酸甲酯的形成。鉴定出的主要产物是乙酰丙酸甲酯和2,4-庚二烯酸甲酯，还形成了少量的羟甲基糠醛。这些结果表明，钒氧基酞菁可有效地用作催化剂，以提高在HSO或HCl-甲醇中果糖转化为乙酰丙酸甲酯的速率。
