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首页> 外文期刊>Landbauforschung >Catalytic conversion of renewables:Kinetic and mechanistic aspects of the gold-catalyzed liquid-phase glucose oxidation
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Catalytic conversion of renewables:Kinetic and mechanistic aspects of the gold-catalyzed liquid-phase glucose oxidation

机译：可再生能源的催化转化：金催化液相葡萄糖氧化的动力学和机理方面

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Among the studies about conversion of renewable resources, glucose oxidation to gluconic acid received very much attention in recent years. The present paper describes kinetic and mechanistic aspects of the liquid-phase glucose oxidation. Therefore a0.3 % Au/Al_2O_3 catalyst prepared by the incipient wetness method was used. The reaction conditions were varied between 20 to 60 deg C, pH 7 to 10, catalyst concentrations between 50 to 1200 mg I~(-1) and initial glucose concentrations between 10 to 1000 mmol I~(-1). The concentration of dissolved oxygen was tracked for most experiments. An increasing activity was found with increasing pH value in the range between pH 7 and 10, and with increasing temperature in the range between 20 and 60 deg C, whereas the selectivity to gluconic acid remained unchanged at > 99 % under these conditions. The activation energy was determined to be 53 kJ mol~(-1). Analysis of the reaction orders with regard to glucose and oxygen leads to the conclusion that the Eley-Rideal model proposed by Beltrame et al. (2006) should be discarded for the gold-catalyzed glucose oxidation. Hydrogen peroxide is formed as by-product in glucose oxidation under oxygen atmosphere, whereas hydrogenated products are by-products under oxygen-free conditions. These observations have been explained by a modified oxidative dehydrogenation mechanism.
机译：在有关可再生资源转化的研究中，近年来葡萄糖氧化为葡萄糖酸受到了极大的关注。本文描述了液相葡萄糖氧化的动力学和机理方面。因此，使用通过初期湿润法制备的0.3％的Au / Al_2O_3催化剂。反应条件在20至60℃，pH 7至10，催化剂浓度在50至1200mg I〜（-1）和初始葡萄糖浓度在10至1000mmol I〜（-1）之间变化。对于大多数实验，跟踪溶解氧的浓度。发现随着pH值在7至10之间的范围内增加的活性以及随着温度在20至60℃之间的范围内的升高的活性而增加，而在这些条件下对葡糖酸的选择性在> 99％时保持不变。活化能确定为53 kJ mol〜（-1）。分析有关葡萄糖和氧气的反应顺序可以得出结论，即Beltrame等人提出的Eley-Rideal模型可以得出结论。 （2006）应丢弃用于金催化的葡萄糖氧化。过氧化氢在氧气气氛下在葡萄糖氧化中作为副产物形成，而氢化产物是在无氧条件下的副产物。这些观察结果已通过改进的氧化脱氢机理进行了解释。

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