摘要
以白炭黑、硼酸等为主要原料,采用水热法合成了硼(B)-β分子筛,对其进行酸洗脱硼处理后使用浸渍法进行锌钇单稀土元素改性和锌钇铒(钕)双稀土元素改性,制备出一系列乙醇转化制丁二烯催化剂。采用SEM、TEM、XRD、N_(2)等温吸脱附、TG-DTA等手段对催化剂的表面结构进行表征,发现双稀土元素改性存在协同作用,能够提高催化剂的乙醇转化率和丁二烯选择性。分子筛母体经酸碱联合处理并进行锌钇化学改性后,以负载质量分数1%ZnO、4%Y_(2)O_(3)样品(B-β-AT 1-HCl-1Zn4Y)的乙醇催化活性最好,其在400℃、乙醇质量空速为6 h^(-1)反应条件下的乙醇转化率为98.53%,丁二烯选择性为55.58%。进一步分析表明:碱处理能够将介孔结构引入沸石中,增大催化剂的比表面积,改善积炭前驱体在分子筛孔道内的扩散性能,增加锌钇物种的分散程度;而高分散锌钇物种和介孔结构的存在,是该类乙醇一步转化制丁二烯催化剂具有高活性的关键因素。
Using white carbon black and boric acid as the main raw materials,the B-βmolecular sieve was synthesized by hydrothermal method.After the elution of boron with acid,the zinc-yttrium single rare earth element modification and the zinc-yttrium-erbium(neodymium)double rare earth element modification were carried out by the impregnation method to prepare a series of catalysts for the conversion of ethanol to butadiene.The surface structures of the catalysts were characterized and analyzed by SEM,TEM,XRD,N_(2)isothermal adsorption-desorption,TG-DTA and other methods.The results showed that the modification by dual rare earth elements had a synergistic effect,which improved the conversion rate of ethanol and the selectivity of butadiene.After the acid and alkali treatments of B-βmolecular sieve precursor and the chemical modification with zinc and yttrium,sample(B-β-AT 1-HCl-1Zn4Y)that loaded with 1%ZnO and 4%Y_(2)O_(3)(mass fraction)exhibited the best catalytic activity.When the reaction was carried out with a space velocity of 6 h^(-1)at 400℃,the ethanol conversion rate of B-β-AT_(1-)HCl-1Zn4Y reached 98.53%with the selectivity of butadiene being 55.58%.Further analysis demonstrated that the mesoporous structure can be introduced into the zeolite after alkali treatment,which increased the specific surface area of the catalysts,improved the diffusion performance of the carbon precursor in the zeolite pores,and enhanced the dispersion of zinc and yttrium species.The existence of these highly dispersed zinc and yttrium species as well as the mesoporous structures is a key factor for the high activity of the catalyst in one-step conversion of ethanol to butadiene.
作者
杨东元
黄肖杰
耿景龙
党舒轩
代成义
常春然
YANG Dongyuan;HUANG Xiaojie;GENG Jinglong;DANG Shuxuan;DAI Chengyi;CHANG Chunran(Shaanxi Key Laboratory of Energy Chemical Process Intensification,School of Chemical Engineering and Technology,Xi′an Jiaotong University,Xi′an 710049,Shaanxi,China;Shaanxi Yanchang Petroleum(Group)Corp.Ltd.,Xi′an 710065,Shaanxi,China;School of Chemical Engineering,Northwest University,Xi′an 710069,Shaanxi,China)
出处
《陕西师范大学学报（自然科学版）》
CAS
CSCD
北大核心
2022年第2期112-120,F0002,共10页
Journal of Shaanxi Normal University：Natural Science Edition
基金
国家自然科学基金(22078257,22108213)
延长石油青年专家联盟项目。
关键词
乙醇
丁二烯
B-β分子筛
稀土元素
ethanol
butadiene
B-βmolecular sieve
rare earth elements
作者简介
通信作者:代成义,男,西北大学化工学院,副教授,博士生导师,研究方向为C1催化。E-mail:daicy@nwu.edu.cn;通信作者:常春然,男,西安交通大学化学工程与技术学院,教授,博士生导师,研究方向为能源催化。E-mail:changcr@mail.xjtu.edu.cn。
