本文選題：原子經(jīng)濟性　切入點：HPPO　出處：《華東師范大學》2017年博士論文

【摘要】：鈦硅分子篩(TS)/H2O2體系因其優(yōu)異的催化性能而受到廣泛重視,而如何實現(xiàn)其催化丙烯環(huán)氧化高效生成PO是HPPO工藝技術發(fā)展的趨勢。論文以綠色化學核心思想-原子經(jīng)濟性為指導,針對TS/H2O2體系催化丙烯環(huán)氧化生成PO的反應,從提高反應體系中的C原子經(jīng)濟性和O原子經(jīng)濟性角度出發(fā),對反應體系中Ti活性中心的構建及其反應行為進行探究,試圖闡明TS/H2O2體系中酸中心本質、高性能Ti活性中心構筑以及影響O有效傳遞的關鍵因素,期望形成的科學認識和技術方法將為研發(fā)新一代HPPO過程高效生成PO工業(yè)技術提供有力的支撐。主要內容包括以下三部分工作。(1)首先,基于建立的HPPO反應體系網(wǎng)絡,設計PO與CH3OH和H2O的溶劑解開環(huán)反應并結合IR光譜的表征,對TS/H2O2體系中的酸中心類型、酸強度以及影響溶劑解開環(huán)反應的因素等進行探究,并提出相應的策略抑制酸中心的影響。結果表明造成HPPO體系中PO溶劑解開環(huán)反應的酸中心有四種,且其醇解開環(huán)反應活性依次呈現(xiàn)Ti-OOHSi-OH(Ti)Ti4+ ≈ Ti-OH。鈦硅分子篩結構中的Si-OH(Ti)基團和TS/H2O2體系中形成的Ti-OOH基團所顯示的Br(?)nsted酸是導致PO發(fā)生醇解開環(huán)反應的主要酸中心。進一步,首次將酸中心類型與相應的醇解產(chǎn)物(1-甲氧基-2丙醇(PPM)和2-甲氧基-1丙醇(SPM))分布進行關聯(lián),發(fā)現(xiàn),Br(?)nsted酸中心催化傾向于生成SPM,而顯示出Lewis酸中心的Ti4+中心傾向于生成PPM。PPM和SPM的產(chǎn)物分布有助于指導對鈦硅分子篩和TS/H2O2體系酸中心的選擇性抑制。通過精細的離子交換和添加劑的引入可以選擇性地對催化劑和催化體系中的酸中心進行抑制,達到PO的高選擇性合成、提高C原子經(jīng)濟性的目的。(2)其次,基于C原子經(jīng)濟性的另一個角度-即提高反應活性,從高性能Ti活性中心的構建出發(fā),成功的定向構建出具有六配位"TiO6"活性中心的TS-1+和開放的四配位Ti(OSi)3OH活性中心的TS-1s催化劑,并對相應的活性中心形成機理以及催化性能進行探討。通過對TS-1進行TPABr和EA水熱處理,成功地合成出具有六配位"TiO6"物種的TS-1+分子篩。過UV-Vis、UV-Raman以及IR等表征結果表明TS-1+中六配位"TiO6"物種是通過骨架四配位"TiO4"物種定向轉變而來。而對其形成過程中微觀結構變化的跟蹤,證明了 "TiO6"物種是通過對Ti周邊的Si進行選擇性地溶解并同時將溶解的Si遷移至外表面晶化而得到,整個過程中未流失骨架Si和Ti物種。通過對"TiO6"物種形成條件的考察,發(fā)現(xiàn)"TiO6"物種形成的關鍵在于控制Si溶解速率與晶化速率的平衡。進一步的催化性能表明具有"TiO6"物種的TS-1+在烯烴環(huán)氧化和環(huán)己酮氨肟化反應具有優(yōu)異的催化氧化性能,并且"TiO6"物種在正己烯環(huán)氧化反應的TON約是傳統(tǒng)"TiO4"物種的2-3倍,是一個具有潛在工業(yè)應用前景的催化劑。通過對TS-1進行小分子胺(EA等)水熱處理,成功地合成出具有開放狀態(tài)的四配位Ti(OSi)3OH活性中心的TS-1s催化劑。通過對其結構的表征及形成過程的跟蹤,發(fā)現(xiàn)Ti(OSi)3OH活性中心是來源于堿對鈦硅分子篩表面閉合的Ti(OSi)4活性中心周邊的Si進行選擇性地溶解轉化而來,且處理過程中未明顯溶硅產(chǎn)生介孔。TS-1s在烯烴環(huán)氧化以及環(huán)己酮氨肟化反應具有優(yōu)異的催化氧化性能,且進一步的半定量分析表明Ti(OSi)3OH活性中心在不同Ti物種中具有最高的催化性能,不同Ti物種之間催化性能依次呈現(xiàn)出Ti(OSi)3OH"TiO6"Ti(OSi)4。(3)最后,由于TS/H2O2體系催化的本質在于H2O2的活化與傳遞,因此基于建立的H2O2反應路徑,以氧化劑(H2O2和t-BuOOH等)利用率作為O傳遞的評價指標,對影響Ti-OOH中間體的形成與穩(wěn)定的Ti活性中心、溶劑、氧化劑、添加劑和反應底物五個因素進行探究。結果表明,對于烯烴環(huán)氧化反應,提高O原子經(jīng)濟性的關鍵在于提高Ti活性中心活化H2O2形成Ti-OOH的能力,并同時通過溶劑和添加劑等的氫鍵作用對其進行穩(wěn)定,促進Ti-OOH中的O異裂形式,進而抑制競爭副反應中H2O2或Ti-OOH的無效分解,實現(xiàn)O的高效傳遞。
[Abstract]:Titanium silicon molecular sieve (TS) /H2O2 system because of its excellent catalytic properties have attracted wide attention, and how to realize the efficient generation of propylene epoxidation catalyzed by PO is HPPO technology development trend. Based on the core idea of green chemistry and atom economy as a guide for generating PO propylene epoxidation catalyzed by TS/H2O2 system. From the point of improving the reaction system C O atom atom economy and economic point of view, construction of the Ti active center in the reaction system and reaction behavior study, attempts to clarify the acid center TS/H2O2 system in essence, the key factors of high performance Ti and O activity center to construct the effective transfer of scientific knowledge and technology method of expectations formation for the development of a new generation of HPPO process for the efficient generation of PO technology to provide strong support. The main contents include the following three parts. (1) first, the establishment of HPPO reaction system based on Network design of PO and CH3OH and H2O of the solvent and ring opening reaction combined with characterization of IR spectra, in the system of TS/H2O2 acid type, acid strength and the influence factors of the reaction solvent and ring opening of inquiry, and puts forward the corresponding strategy effect of inhibiting acid center. The results showed that PO caused by acid solvent and ring opening reaction the HPPO system has four kinds, and the alcoholysis reaction of ring opening activity were presented Ti-OOHSi-OH (Ti) Ti4+ = Ti-OH. titanium silicon molecular sieve structure in Si-OH (Ti) Ti-OOH group and TS/H2O2 group formed in the system shown in Br (?) nsted Acid is the main cause of PO acid sites by ring opening reaction for the first time. Further, the acid type and corresponding alcoholysis products (1- methoxy propanol (-2 PPM) and 2- methoxy propanol (SPM) -1) Distribution Association, found that Br (?) nsted Acid Catalyzed tend to form SPM, which showed that Lewis acid A selective guide to the titanium silicon molecular sieve and TS/H2O2 acid center product distribution center inhibit heart Ti4+ tend to generate PPM.PPM and SPM. Through the introduction of ion exchange and fine additives can inhibit the acid catalyst and catalytic system selectively, high selective synthesis of PO, improve the C atom economy. (2) second, another point of C atom economy -- Based on enhancing the activity, starting from the construction of high performance Ti active center, successfully constructed has six directional coordination "TiO6" activity in the heart of TS-1+ and open the four coordinated Ti (OSi) TS-1s catalyst 3OH active center, and the active center of the corresponding formation mechanism and Catalytic Performance were discussed. Based on the TS-1 TPABr and EA hydrothermal treatment was successfully synthesized with six coordinated TS-1+ molecular sieve TiO6 species. UV-Vis, UV-R Aman and IR characterization results show that TS-1+ in the six coordination "TiO6" species by four coordinate framework "change TiO4" species orientation. And the formation of microstructure changes in the process of tracking the show "TiO6" species is selectively dissolved by Ti and Si at the same time will dissolve around Si migration to the outer surface crystallization by skeleton Si and Ti species without loss in the whole process. Through the investigation on the formation of "TiO6" species, found that the "TiO6" key species in the formation of Si dissolution rate and the crystallization rate control balance. Further catalytic performance showed that the "TiO6" species TS-1+ has excellent catalytic performance in the epoxidation of olefin and ammoximation of cyclohexanone, and "TiO6" species in the epoxidation of n-hexene TON is about 2-3 times of the traditional "TiO4" species, is a potential industrial application prospect through the catalyst. TS-1 small molecular amine (EA) hydrothermal treatment was successfully synthesized with the open state of the four coordinated Ti (OSi) TS-1s 3OH catalyst active center. Through the formation and characterization of its structure, the process of tracking, Ti (OSi) 3OH activity center is derived from alkali on titanium silicon molecular sieve surface closed Ti (OSi) activity center 4 surrounding Si selective dissolution and transformation to process, and no obvious solution silicon mesoporous.TS-1s has excellent catalytic performance in the epoxidation of olefin and ammoximation of cyclohexanone, and further semi quantitative analysis showed that Ti (OSi) 3OH activity the center has the highest catalytic performance in different Ti species, the catalytic performance between different Ti species appeared in order Ti (OSi) 3OH "TiO6" Ti (OSi) 4. (3) finally, due to the nature of TS/H2O2 catalyst system is activated and transfer of H2O2 based on H2O2, so the reaction path established, The oxidant (H2O2 and t-BuOOH) using O transfer rate as the evaluation index, the Ti activity center, influence the formation of Ti-OOH intermediate and stable solvent, oxidant, additive and substrate five factors were explored. Results show that for the epoxidation of olefins, provided the key high atom economy is O increase the activity of Ti activated H2O2 Ti-OOH center formation ability, and at the same time by hydrogen bonding solvents and additives on the stability of Ti-OOH in O, promote heterolytic form, thereby inhibiting invalid decomposition of H2O2 or Ti-OOH in the competition side reaction, efficient delivery of O.

【學位授予單位】：華東師范大學
【學位級別】：博士
【學位授予年份】：2017
【分類號】：O643.36

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本文編號：1721953