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Mechanism of chain propagation for the synthesis of polyoxymethylene dimethyl ethers 被引量:36
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作者 Yupei Zhao Zheng Xu +2 位作者 Hui Chen Yuchuan Fu Jianyi Shen 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2013年第6期833-836,共4页
Polyoxymethylene dimethyl ethers(PODE)were synthesized from the reaction of paraformaldehyde with dimethoxymethane(DMM)over different acid catalysts at different conditions.Products were found to follow the Schulz-Flo... Polyoxymethylene dimethyl ethers(PODE)were synthesized from the reaction of paraformaldehyde with dimethoxymethane(DMM)over different acid catalysts at different conditions.Products were found to follow the Schulz-Flory distribution law.The chain propagation proceeds through the insertion of an individual segment of CH2O one by one,while the simultaneous insertion of a few CH2O segments or their assembly is unlikely.Due to the restriction of this law,it is difficult to increase the selectivity to the desired products(e.g.,PODE3 4). 展开更多
关键词 polyoxymethylene dimethyl ethers (PODE) diesel additive chain propagation product distribution Schulz-Flory law
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Studies on polyoxymethylene dimethyl ethers production from dimethoxymethane and 1,3,5-trioxane over SO_(4)^(2-)/ZrO_(2)-TiO_(2)
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作者 Haoyu Yao Jiangcheng Li +3 位作者 Jiangyan Li Xiangfeng Liang Gang Wang Haiyan Luo 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2023年第9期24-36,共13页
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
关键词 Polyoxymethylene dimethylethers SO_(4)^(2-)/ZrO_(2)-TiO_(2) chain propagation Kinetics Deactivation behavior
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Nondilute 1,2-Dichloroethane Solution of Poly(9,9-dioctylfluorene-2,7-diyl):A Study on the Aggregation Process 被引量:1
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作者 Meng-na Yu Bin Liu +6 位作者 林进义 Tao Li 陆丹 Feng Liu Wen-sai Zhu Ling-hai Xie 黄维 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2016年第11期1311-1318,共8页
Molecular aggregates in conjugated polymer(CP) solution can propagate into mesoscale morphology of the relevant film and further dominate the optoelectronic property. Herein, we probed the aggregation behavior of p... Molecular aggregates in conjugated polymer(CP) solution can propagate into mesoscale morphology of the relevant film and further dominate the optoelectronic property. Herein, we probed the aggregation behavior of poly(9,9-dioctylfluorene-2,7-diyl)(PFO) and studied its influence on the photophysical property in 1,2-dichloroethane(DCE) solution, where the contents of β-phase or-aggregates increased with prolonged aging time. Thereinto, high quality β-film was fabricated from DCE solution with critical aggregate time of 6 min. The film exhibited excellent surface morphology and characteristic emission of β-phase. Meanwhile, films prepared from aged DCE solutions exhibited high crystallinity, which was promising to obtain higher photoluminance efficiency and charge transport ability simultaneously. Therefore, it is significant to get deep insight into the aggregation behavior of CP, which is involved not only with the solution-processing technology of plastic device, but also with the optoelectronic property of CP. 展开更多
关键词 aggregation crystallinity conjugated aggregate optoelectronic chains propagate mesoscale insight stacking
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