Synthesis And Deep Desulfurization Performance Of Functional Materials Based On Hydrotalcite Carrier

In recent years,deep desulfurization of fuel oil has attracted worldwide attention.In order to reduce the sulfur oxides(SO_X)produced by the combustion of sulfur-containing compounds in fuel oil,the European Union has issued increasingly stringent environmental regulations(<10ppm)on the sulfur content of fuel oil,although the current hydrodesulfurization which is considered to be the most convenient and most important synthetic method in the industry,but the severe operating conditions(high temperature573-723 K,high pressure 3.0-4.5 MPa)and the inability to effectively remove aromatic sulfides limit its deep desulfurization Application prospects.What is gratifying is that oxidative desulfurization,which is milder(<373K,normal pressure)than the hydrodesulfurization reaction conditions,which can effectively remove sulfur-containing compounds at an ultra-deep level,which has attracted the attention of researchers as a branch of oxidative desulfurization.The extraction catalytic oxidation desulfurization is the most widely used method in oxidative desulfurization.Because of the atoms between the main layers of hydrotalcite are connected by covalent bonds,the guest anions of the main layer and the intermediate layer are combined by ionic bonds or hydrogen bonds,and they are stacked to form a layered structure.This kind of interaction between layers is weak,which makes it exhibit good scalability.In this paper,functional materials based on polyacid or metal-organic framework are synthesized by different methods:the polyacid is loaded on the solid hydrotalcite substrate modified with amphiphilic surfactant,and the metal-organic framework is loaded on the rod-shaped hydrotalcite.It is beneficial to improve the catalytic effects of polyacids or organometallic frameworks,and can also effectively increase the number of recycling of polyacids as well as effectively improve the agglomeration defects of organometallic frameworks.In recent years,polyacids have shown superior catalytic performance as catalysts in various catalytic fields,especially Keggin-type polyacids,which have outstanding catalytic activity in the field of deep desulfurization.The main experimental results of this paper are as follows:1.First,synthesize different Keggin-type polyacids with amphiphilic surfactant sodium dodecyl sulfonate(SDS)modified hydrotalcite MgAl-LDH-DS for chemical reaction to obtain three catalysts respectively:(1)[(n-C₄H₉)₄N]₃[PW₁₂O₄₀]@MgAl-LDH-DS,referred to as PW₁₂-LDH-DS(2)[(n-C₄H₉)₄N]₃[PMo₁₂O₄₀]@MgAl-LDH-DS,referred to as PMo₁₂-LDH-DS(3)[(n-C₄H₉)₄N]₄[H₃PMo₁₁O₃₉]@MgAl-LDH-DS,referred to as PMo₁₁-LDH-DS Compared with the other two catalysts,PW₁₂-LDH-DS has better desulfurization effect.At323K,the catalyst is 0.01g PW₁₂-LDH-DS,the oxidant is H₂O₂,and the extractant is ionic liquid 1-butyl-3methyl Based on imidazole hexafluorophosphate([Bmim]PF₆),the sulfur compounds in 500ppm DBT simulated oil can be completely oxidized to sulfones and sulfoxides in only 20 minutes.The desulfurization effect of different sulfides shows DBT>4,6-DMDBT>BT,and it is easy to recover and reuse the catalyst from the desulfurization system.Only the organic solvent acetonitrile is used for centrifugation.The desulfurization effect can be continued for 5 times without significant change,and It also showed a good desulfurization effect in the mixed simulated oil,indicating that it has a greater application prospect in actual industrial desulfurization.2.Synthesis The rod-shaped hydrotalcite was obtained by hydrothermal synthesis,and then a series of metal organic framework MOF76 was loaded on the rod-shaped hydrotalcite by in-situ hydrothermal self-assembly method to obtain a series of x wt.%MOF76@LDH,of which 49%MOF76@LDH has the best desulfurization effect.It is determined by inductively coupled plasma atomic emission spectroscopy(ICP-AES)and X-ray photoelectron spectroscopy that the heterogeneous catalyst 49%MOF76@LDH is Ca_0.03Mg_0.35Al_0.50Tb_0.12(OH)_1.72][C₉H₃O₆]_0.30[NO₃]_0.05·1.83H₂O,referredtoas49%MOF76@LDH.When the best reaction condition for this catalyst for desulfurization reaction is 333K,0.010g of 49%MOF76@LDH can convert all DBT into sulfone or sulfoxide in only 25min under the condition of O/S molar ratio of 3:1,The desulfurization effect of different sulfides shows DBT>BT>4,6-DMDBT,and after 5 cycles,the desulfurization effect is only slightly reduced,and it also shows good desulfurization effect in the mixed simulated oil,indicating its practical application in industry desulfurization has greater application prospects.This article also explored the desulfurization mechanism in detail.