磷钨酸插层MgAl水滑石层间距的调变及催化酯化脱酸性能  

Preparation of tungstophosphoric acid intercalated MgAI layered double hydroxides with a tunable interlayer spacing and their catalytic esterification performance in the deacidification of crude oil

作　　者：王豪[1] 李冬梅 吴雁[1] 丁瑜 WANG Hao;LI Dong-mei;WU Yan;DING Yu(School of Chemistry and Chemical Engineering,Southwest Petroleum University,Chengdu 610500,China;State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Southwest Petroleum University,Chengdu 610500,China)

机构地区：[1]西南石油大学化学化工学院,四川成都610500 [2]西南石油大学油气藏地质及开发工程国家重点实验室,四川成都610500

出　　处：《燃料化学学报》2020年第1期44-51,I0004,共9页Journal of Fuel Chemistry and Technology

基　　金：国家自然科学基金(21506176)资助~~

摘　　要：通过改变离子交换温度和时间合成了具有不同层间距的磷钨酸(H 3PW 12 O 40,HPW)插层MgAl水滑石(LDHs),采用XRD、FT-IR、Raman、31 P MAS NMR、ICP-AES和Hammett指示剂-正丁胺滴定法等表征其性质,并研究其对模型原油的催化酯化脱酸性能。高的离子交换温度有利于形成较大的层间距(d 003约1.46 nm),较长的交换时间有利于形成较小的层间距(d 003约1.05 nm)。不同的层间距源自HPW在层间不同的存在形式,P 2W 18 O 6-62以C 2轴倾斜于层板和PW 11 O 7-39以C 2轴垂直于层板的方式排列于层间时,形成d 003约1.46 nm的层间距;PW 12 O 3-40与层板发生嫁接,并以C 2轴垂直于层板的方向排列于层间时,形成d 003约1.05 nm的层间距。层间P 2W 18 O 6-62和PW 11 O 7-39能产生更高比例的中强酸中心,同时大的层间距有利于反应物扩散进入层间与酸中心接触,能够提高LDHs的催化酯化脱酸性能。This study demonstrates the synthesis of MgAl layered double hydroxides(LDHs)intercalated with tungstophosphoric acid(H 3PW 12 O 40,HPW)by an ion exchange method,and different interlayer spacings(d 003)are obtained by adjusting the ion exchange temperature and time.The crystalline structures,molecular structures,atomic compositions,acidity,and specific surface areas of the LDH samples are rigorously characterized.A relatively high ion exchange temperature is demonstrated to be favorable for the formation of a large d 003 value of around 1.46 nm,while a long exchange time is favorable for the formation of a small d 003 value of around 1.05 nm.The different values of d 003 are the result of different orientations of HPW anions within the interlayer space.Here,d 003=1.46 nm is obtained when P 2W 18 O 6-62 and PW 11 O 7-39 anions are arranged in the interlayer with their C 2 axes respectively tilted toward and perpendicular to the LDH layer planes.In contrast,d 003=1.05 nm is obtained when PW 12 O 3-40 anions are grafted onto the LDH layers with their C 2 axis perpendicular to the layer planes.Furthermore,the catalytic esterification performance of the samples is investigated for the deacidification of a model crude oil.Compared with PW 12 O 3-40 anions,the presence of P 2W 18 O 6-62 and PW 11 O 7-39 anions in the interlayer produce a higher proportion of sites with intermediate acidity that function as catalytic sites.Moreover,a large value of d 003 facilitates the diffusion of reactants into the interlayer,which enhances their contact with the catalytic sites,and thereby increases the catalytic esterification performance of the LDHs in the deacidification of crude oil.

关 键 词：磷钨酸 水滑石 层间距 酯化 脱酸 

分 类 号：O643.361[理学—物理化学]