Polyoxymethylene dimethyl ethers(OMEs)with physical properties similar to those of diesel has received significant attention as green additives for soot emission suppression.Herein,series of SO_(4)^(2-)/ZrO_(2)-TiO_(2...Polyoxymethylene dimethyl ethers(OMEs)with physical properties similar to those of diesel has received significant attention as green additives for soot emission suppression.Herein,series of SO_(4)^(2-)/ZrO_(2)-TiO_(2)catalysts were developed for OMEs production from dimethoxymethane(DMM)and1,3,5-trioxane through sequential formaldehyde monomer insertion into C-O bond of DMM.Not Lewis but Bronsted acid sites were identified to be active for the decomposition of 1,3,5-trioxane into formaldehyde unit,however,both of them are effective for the chain propagation of DMM via formaldehyde unit insertion into C-O bond.Kinetic studies indicated each chain growth step exhibited the same parameters and activation barrier on corresponding Bronsted and Lewis acid sites due to the same reaction mechanism and very similar chemical structure of OMEs.Also,the catalytic stability investigation suggested the deactivation behavior was derived from the carbon deposition,and the decay factor could be exponentially correlated with the amount of coke accumulation.展开更多
Highly active solid superacid catalysts for n-butane isomerization, SZ/A1_2O_3-P, were prepared by supporting SO-(4-2)/ZrO2, (SZ) on y-A1_2O_3 carrier using a precipitation method. The activities of some catalysts wer...Highly active solid superacid catalysts for n-butane isomerization, SZ/A1_2O_3-P, were prepared by supporting SO-(4-2)/ZrO2, (SZ) on y-A1_2O_3 carrier using a precipitation method. The activities of some catalysts were enhanced significantly j The activity of the most active sample. 60%SZ/Al_2O3-P, was even about 2 times more active than that of the SZ catalyst.展开更多
SO4^2-/TiO2-MoO3, a novel solid superacid, has been prepared and its catalytic activity at different synthetic conditions was examined with esterification of n-butanoic acid and n-butyl alcohol as probing reaction.The...SO4^2-/TiO2-MoO3, a novel solid superacid, has been prepared and its catalytic activity at different synthetic conditions was examined with esterification of n-butanoic acid and n-butyl alcohol as probing reaction.The optimum conditions were also found, that is, the mass ratio of MoO3 used in the compound is 25%, the calcination temperature 450℃, and the soaked consistency of H2SO4 is 0.5mol.L^-1. Then it was applied in the catalytic synthesis of six similar important ketals and acetals as catalyst and revealed high catalytic activity. Under the condition that the molar ratio of aldehyde/ketone to glycol was 1:1.5, the mass ratio of the catalyst to the reactants was 0.5% and the reaction time 1.0 h, the yield of ketals and acetals reached up to 63.2%. The catalyst can be easily recovered and reused.展开更多
基金the fund from the National Natural Science Foundation of China(22208349)the Innovation Academy for Green Manufacture(Chinese Academy of Sciences,IAGM2020C20)+1 种基金Shandong Provincial Natural Science Youth Fund(ZR2022QB244)Japan Society for the Promotion of Science(P20345)。
文摘Polyoxymethylene dimethyl ethers(OMEs)with physical properties similar to those of diesel has received significant attention as green additives for soot emission suppression.Herein,series of SO_(4)^(2-)/ZrO_(2)-TiO_(2)catalysts were developed for OMEs production from dimethoxymethane(DMM)and1,3,5-trioxane through sequential formaldehyde monomer insertion into C-O bond of DMM.Not Lewis but Bronsted acid sites were identified to be active for the decomposition of 1,3,5-trioxane into formaldehyde unit,however,both of them are effective for the chain propagation of DMM via formaldehyde unit insertion into C-O bond.Kinetic studies indicated each chain growth step exhibited the same parameters and activation barrier on corresponding Bronsted and Lewis acid sites due to the same reaction mechanism and very similar chemical structure of OMEs.Also,the catalytic stability investigation suggested the deactivation behavior was derived from the carbon deposition,and the decay factor could be exponentially correlated with the amount of coke accumulation.
文摘Highly active solid superacid catalysts for n-butane isomerization, SZ/A1_2O_3-P, were prepared by supporting SO-(4-2)/ZrO2, (SZ) on y-A1_2O_3 carrier using a precipitation method. The activities of some catalysts were enhanced significantly j The activity of the most active sample. 60%SZ/Al_2O3-P, was even about 2 times more active than that of the SZ catalyst.
文摘SO4^2-/TiO2-MoO3, a novel solid superacid, has been prepared and its catalytic activity at different synthetic conditions was examined with esterification of n-butanoic acid and n-butyl alcohol as probing reaction.The optimum conditions were also found, that is, the mass ratio of MoO3 used in the compound is 25%, the calcination temperature 450℃, and the soaked consistency of H2SO4 is 0.5mol.L^-1. Then it was applied in the catalytic synthesis of six similar important ketals and acetals as catalyst and revealed high catalytic activity. Under the condition that the molar ratio of aldehyde/ketone to glycol was 1:1.5, the mass ratio of the catalyst to the reactants was 0.5% and the reaction time 1.0 h, the yield of ketals and acetals reached up to 63.2%. The catalyst can be easily recovered and reused.
