The sulfonated H‐β zeolite was successfully prepared and used for the synthesis of levulinic acid (LA) from D‐fructose. The catalyst was characterized by powder X‐ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscope, N₂ physisorption, NH₃‐temperature programmed desorption and carbon–hydrogen–nitrogen–sulfur analysis. The total acid amount is increased with increase in sulfur loading, confirmed that the sulfonic acid group (SO₃‐H) is successfully grafted onto zeolite structure. The various parameters such as different amount of sulfur loading, reaction temperature, time, catalyst loading was studied for selective production of LA. The catalytic activity of sulfonated H‐β (S‐β) zeolite was found to be efficient for synthesis of LA from D‐fructose in aqueous media. Maximum LA yield of 43.5 mol%, low HMF yield (<1%) with 98.15% fructose conversion was obtained with 3% S‐β catalyst at 160°C for 7 hr. The catalyst was reusable for minimum three times by H₂O₂ regeneration. This study provides the new zeolitic catalyst for the efficient production of LA at shorter reaction time (7 hr) and low catalyst to substrate ratio (0.7:1).

中文翻译：

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水性介质中磺化H-β沸石将果糖一步转化为乙酰丙酸的较温和操作参数

成功地制备了磺化的H-β沸石和用于乙酰丙酸从合成（LA）d -fructose。该催化剂的特征在于粉末X射线衍射，傅里叶变换红外光谱，扫描电子显微镜，N ₂物理吸附，NH ₃程序升温脱附以及碳-氢-氮-硫分析。总酸量随硫载量的增加而增加，证实了磺酸基（SO ₃‐H）成功接枝到沸石结构上。研究了选择性生产LA的各种参数，例如不同的硫负载量，反应温度，时间，催化剂负载。发现磺化H-β（S-β）沸石的催化活性可有效地在水性介质中由D-果糖合成LA 。在160°C下使用3％S-β催化剂在7个小时内可获得最高LA收率为43.5 mol％，低HMF收率（<1％）和98.15％果糖转化率。通过H ₂ O ₂再生，该催化剂至少可重复使用3次。这项研究提供了一种新型的沸石催化剂，可在较短的反应时间（7小时）和较低的催化剂与底物比率（0.7：1）下高效生产LA。