發(fā)布時(shí)間：2019-02-24 20:44

【摘要】：甲醇作為煤化工和石油化工的產(chǎn)品在化工生產(chǎn)中具有極其重要的應(yīng)用,但是今年來(lái)由于甲醇生產(chǎn)過(guò)剩,所以將甲醇制備為下游高附加值化學(xué)品具有重要的研究意義。其中,甲醇選擇性氧化可以用于制備一系列具有工業(yè)應(yīng)用價(jià)值的化學(xué)產(chǎn)品。甲酸甲酯作為甲醇氧化的下游產(chǎn)品,具有重要的工業(yè)價(jià)值,不僅僅可以作為藥物生產(chǎn)以及有機(jī)合成的中間體,同時(shí)可以用于生產(chǎn)多碳分子碳?xì)浠衔�。傳統(tǒng)制備甲酸甲酯的方法需要多步反應(yīng),反應(yīng)副產(chǎn)物較多,不利于后期的分離。因此,利用雙功能催化劑通過(guò)一步反應(yīng)將甲醇轉(zhuǎn)化為具有高附加值的甲酸甲酯具有重要的經(jīng)濟(jì)意義。甲醇氧化反應(yīng)一步制取甲酸甲酯的合成路線(xiàn)由于其獨(dú)特的優(yōu)點(diǎn)已經(jīng)吸引了學(xué)術(shù)界和工業(yè)上的廣泛關(guān)注。雖然目前利用甲醇選擇性氧化法生產(chǎn)甲酸甲酯的工業(yè)化技術(shù)還遠(yuǎn)未成熟,但是利用該法可以直接一步制備甲酸甲酯,經(jīng)濟(jì)高效,其中,雙功能催化劑的設(shè)計(jì)以及制備具有重要的意義。本文使用等體積浸漬法將V2O5負(fù)載在SiO2、γ-A12O3、ZrO2和TiO2等載體表面,通過(guò)催化劑對(duì)甲醇氧化反應(yīng)性能的研究發(fā)現(xiàn)以Ti02為載體時(shí)催化劑的活性最高。之后,通過(guò)對(duì)催化劑制備過(guò)程中不同V205負(fù)載量和不同焙燒溫度條件的研究,優(yōu)化了催化劑制備的條件,并對(duì)催化劑進(jìn)行了改性,同時(shí)采用XRD、FTIR、TPR、TPD和XPS等方法對(duì)催化劑的結(jié)構(gòu)進(jìn)行了表征,并采用固定床反應(yīng)器對(duì)催化劑的性能進(jìn)行了評(píng)價(jià)。利用Ti02作為載體制備了 V205負(fù)載量分別為1wt%、5wt%、10wt%、15wt%和20wt%的一系列催化劑,結(jié)果表明:焙燒溫度為500℃,10wt%V2O5/TiO2催化劑對(duì)于甲醇氧化反應(yīng)的活性最高。之后,通過(guò)對(duì)反應(yīng)條件的優(yōu)化,表明在催化劑裝填量為0.10 g,氧氣流量為20 mL/min、氮?dú)饬髁繛?0 mL/min,190 ℃的反應(yīng)條件下,甲醇轉(zhuǎn)化率可以達(dá)到44.94%,同時(shí),甲酸甲酯的選擇性和收率分別為61.01%和27.42%。最后測(cè)試了 10wt%V2O5/TiO2催化劑的穩(wěn)定性,在持續(xù)催化反應(yīng)80小時(shí)后,甲醇轉(zhuǎn)化率和甲酸甲酯的選擇性均只略有下降,這說(shuō)明該催化劑對(duì)于甲醇氧化反應(yīng)具備一定的穩(wěn)定性。之后,本文研究了不同助劑對(duì)于催化劑改性的效果。分別添加MgO、La203、CeO2、CoO、CuO、ZrO2、Y2O3、Mo03 對(duì) Ti02載體改性制備出復(fù)合載體后,制備了一系列改性的10wt%V2O5/TiO2催化劑。結(jié)果表明,Zr02助劑對(duì)催化劑的活性具有最好的改進(jìn)效果。之后,優(yōu)化了 Ti02-ZrO2復(fù)合載體的制備條件,當(dāng)ZrO2添加量為10wt%,通過(guò)等體積浸漬法,在500℃下焙燒所制備的復(fù)合載體催化劑對(duì)甲醇氧化反應(yīng)具有最高活性,其甲醇轉(zhuǎn)化率可以達(dá)到50.34%,甲酸甲酯的選擇性和收率為61.77%和31.10%。
[Abstract]:Methanol, as a product of coal chemical industry and petrochemical industry, has very important applications in chemical production. However, because of the excess production of methanol this year, it is of great significance to study the preparation of methanol as a high value-added chemical downstream. Among them, methanol selective oxidation can be used to prepare a series of chemical products with industrial application value. Methyl formate, as a downstream product of methanol oxidation, has important industrial value, not only as an intermediate in drug production and organic synthesis, but also in the production of multi-carbon hydrocarbons. The traditional method for the preparation of methyl formate requires multi-step reaction, and the byproducts of the reaction are many, which is not conducive to the later separation of methyl formate. Therefore, the conversion of methanol to methyl formate with high added value by one step reaction with bifunctional catalyst has important economic significance. The synthesis of methyl formate by one step methanol oxidation has attracted much attention in academia and industry because of its unique advantages. Although the industrial technology for the production of methyl formate by selective oxidation of methanol is still far from mature, the method can be used to produce methyl formate directly in one step, which is economical and efficient. The design and preparation of bifunctional catalysts are of great significance. In this paper, V2O5 was supported on the surface of SiO2, 緯 -A12O3ZrO2 and TiO2 by the method of equal volume impregnation. It was found that the activity of the catalyst was the highest when Ti02 was used as the carrier for methanol oxidation. After that, the conditions of catalyst preparation were optimized by studying the different loading amount of V205 and different calcination temperature during the preparation of catalyst, and the catalyst was modified, and XRD,FTIR,TPR, was used at the same time. The structure of the catalyst was characterized by TPD and XPS, and the performance of the catalyst was evaluated by fixed-bed reactor. A series of catalysts with V205 loading amount of 1 wtand 5 wtand 10wt% and 20wt% were prepared by using Ti02 as the carrier. The results showed that the calcination temperature was 500 鈩，

本文編號(hào)：2429915