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用于合成聚对苯二甲酸乙二醇酯的KF/Al2O3催化剂研究

Study of KF/Al2O3 Catalyst in Synthesis of Poly(ethylene terephthalate) by Esterification
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摘要 采用浸渍法制备了KF/Al2O3催化剂,研究了KF含量和焙烧温度对KF/Al2O3催化剂结构、活性和性能的影响,采用X射线衍射(XRD)、扫描电子显微镜(SEM)和N2低温物理吸附对KF/Al2O3催化剂的结构进行表征,也用Hammett indicator测定了KF/Al2O3催化剂的碱度和碱量.探讨了KF含量、焙烧温度与KF/Al2O3催化剂结构、碱度和碱量的关系以及KF/Al2O3催化剂结构、碱度和碱量与其用于酯化法合成聚对苯二甲酸乙二醇酯(PET)催化活性的关系.研究结果表明,KF/Al2O3催化剂中出现了K3AlF6、KAlO2和K2CO3等新的物相,催化剂中的中等强度的碱性有利于PET的聚合反应、强碱性会促进PET的降解反应. KF含量为25%,在400°C焙烧的25-KF/Al2O3-400催化剂中含γ-Al2O3、K3AlF6和少量K2CO3,碱性和碱量适中,催化活性最好,制备的PET的特性黏数为1.07 dL/g、端羧基值为20.29 mol/t、二甘醇含量为2.85%、聚酯黄度(L)值为86.6和聚酯白度(b)值为4.6. A series of KF/Al2O3 solid base catalysts were prepared by a wet impregnation method and applied to the synthesis of poly(ethylene terephthalate)(PET) from 1,4-dicarboxybenzene and ethylene glycol. The effect of KF content and calcination temperature on the structure, active components and properties of the catalysts were investigated. The structure of KF/Al2O3 catalysts was characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM) and BET. The basic strength and basicity of KF/Al2O3 catalysts were measured by Hammett indicator. The relationship between KF content, calcination temperature and the structure, basic strength and basicity of KF/Al2O3 catalyst was investigated. The relationship between the structure, basic strength and basicity of KF/Al2O3 catalysts and the catalytic activity in PET synthesis was also studied. The results showed that KF/Al2O3 catalysts could be used to synthesize high-molecular-weight PET. It was found that several types of basic centers such as K3 AlF6, KAlO2, K2 O and K2CO3 existed in the catalyst. The specific surface area of KF/Al2O3 was reduced with increasing KF content. The particle size of KF/Al2O3 increased with increasing KF content. The basic strength and basicity of KF/Al2O3 increased with increasing KF content and calcination temperature. The activity of KF/Al2O3 was related to the basic strength and basicity and was not really influenced by the specific surface area and particle size. Medium strength basic sites were responsible for the higher intrinsic viscosity, and strong basic sites could cause decomposition of the obtained polymer. Strong basic sites were mainly due to potassium carbonate, potassium aluminate and potassium oxide. The catalytic effect of 25-KF/Al2O3-400 was better than that of Sb2O3. It contained γ-Al2O3, K3 AlF6 and a small amount of K2CO3. It had moderate basic strength, basicity and high activity. Based on the obtained results, the possible active site was K3 AlF6. The intrinsic viscosity of 1.07 dL/g, with carbox
作者 蔡志锋 王庆印 刘绍英 王公应 Zhi-feng Cai1, 3 Qing-yin Wang1, 2 Shao-ying Liu1, 2,, Gong-ying Wang1, (1.Chengdu Institute of Organic Chemistry, 2.Chendu Organic Chemicals Co. Ltd., Chinese Academy of Sciences, Chengdu 610041;3.University of Chinese Academy of Sciences, Beijing 100049)
出处 《高分子学报》 CSCD 北大核心 2018年第9期1184-1193,共10页 Acta Polymerica Sinica
基金 国家重点研发计划项目(项目号2016YFB0301900) 四川省科技支撑计划项目(项目号2015GZ0065)资助
关键词 KF/AL2O3 碱度与碱量 构效关系 聚对苯二甲酸乙二醇酯 KF/Al2O3 Basic strength and basicity Structure-activity relationship Poly(ethylene terephthalate)
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