液态石油烃的脱砷及砷化物与亚铜探针的相互作用

Dearsenication of Liquid Hydrocarbons and Interaction between Arsenic Compounds and Cuprous Probes

采用密度泛函理论B3LYP方法,在6-311+G(2df,2p)基组水平上研究了液态石油烃体系中甲基胂化合物与过渡金属探针Cu+和CuCl的相互作用.结果表明,甲基胂化物与亚铜离子作用的最稳定模式为四面体构型,随着烃基取代数增加,砷化物同Cu+或CuCl的相互作用能(E0)更负,配合物更稳定,同时二者的相互作用轨道的能级差(△E)与E0值线性相关(R2≥0.99).Cu+配合物中,As—Cu成键轨道向C—As和/或H—As反键轨道形成电子反馈,但是CuCl配合物中类似电子反馈则没有形成.烃基取代并不降低活性组分对砷化物的吸附活性,在活性组分满足砷化物选择性吸附的条件下,液态石油烃脱砷的主要控制因素为砷化物在脱砷剂内部孔道中的扩散传输.有机硫化物噻吩并不影响砷化物的选择性吸附分离,硫醇类化合物则会影响单烷基砷化物的选择性吸附.在进行脱砷剂开发时,应拓宽载体孔道以提高流体传输效率,并选择活性相组分与砷化物作用的△E相对较小,配合物容易形成电子反馈,且对硫醇类化合物的作用能力相对较弱,对单烷基砷化物的作用能力相对较强的过渡金属组分.

The interaction between alkylarsines and transition metal probes （Cu^＋ and CuCl） in liquid hydrocarbon was studied using density functional theory, the B3LYP method and the 6-311＋G（2df,2p） basis set. Results showed that the most stable interaction mode of the alkylarsines with Cu^＋ or CuCl was a classic tetrahedral structure. A higher alkyl substitution number led to a more negative interaction energy （E0） and more stable alkylarsine-Cu^＋ or alkylarsine-CuCl complexes. The energy difference （AE） between the interaction orbital of arsines and Cu^＋ or CuCl had a linear correlation to E0 （R2≥0.99）. A feedback of electrons from the As--Cu bond to the C--As bond and/or H--As anti-bond in alkylarsine-Cu^＋ complexes existed while a similar feedback phenomenon did not appear in alkylarsine-CuCl complexes. Alkyl substitution did not decrease the interaction capability between the arsines and the active purification component. If the selective adsorption for arsines can be achieved, even if competing compounds exists, the key factor that affects arsenic removal performance will be the diffusion of arsines into the pores of the purificants. Thiophene compounds in the liquid hydrocarbon did not affect the selectivity of the arsinic adsorptive separation, however, the existence of mercaptans such as CH3SH decreased the adsorption of monoalkylarsines. For the development of new purificants for the removal of arsenic, an expansion of the support pore to increase diffusion should be considered and the active component should have a relatively lower AE, stronger electron feedback in formed complexes, weaker interactions with mercaptans and stronger interactions with monoalkylarsines.